Rebuilding Zenith-Stromberg CD-175 Carburetors - Disassembly
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- Опубликовано: 4 июн 2020
- This is the next in a series of videos showing how a TR6 was rescued from a garage and put back on the road. Many cars used Zenith-Stromberg Carburetors. While there were many variations, and while this was done on carburetors from a Triumph TR6... it's the same principles that would apply to your MG, Lotus, Jaguar--you name it. If your car runs something similar to these CD-175s, these videos will help!
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One of the best videos I have seen, no blah blah off topic, no awful background music, just good quality training and explanation. Thanks for taking the time. Richard
Wow, thanks! I know what you mean about background music and such. A tripod and microphone both help a lot!
I put the points back in and it runs great as before. Thanks for all your help. Keep up the great videos!
Great to hear! Keep that car on the road!
I'm loving your videos keep them coming. Thanks alot
Thanks, will do! The wife and I had a few foster children, so I didn't have much time to create these. The kids are back with their family now though, so you can expect more!
Wow! What an awesome video. Incredible tutorial and such a huge help in figuring out my carbs on my ‘80 triumph TR7. Thank you!👍🏻
Glad to be able to help! The TR7 is underrated.
Thank you so much, and my 1972 Jaguar XJ6 says thank you also! Great explanation, so easy to follow.
I was actually just reorganizing my Jag shop manuals (because I'm that boring).... if you think you might want more tech support now that the carbs are done, consider joining as a member. Thanks for the comment!
Great video. Clear, well shot.
My wife bought me a DSLR camera years ago, and I decided to pick up a better microphone to play with. There's advice out there on the internet, but it's either photos or often poor video quality (shaky camera, etc). I kept thinking "a tripod would go a long way!" Then the pandemic hit, and I found myself bored with information in my head. Glad the videos are helpful!
Great video, learned alot as I'm rebuilding my 175cd for my 82 Tr7.
Glad I could help. The TR7 carbs may have some additional stuff such as a water choke. Depending on whether you'd like to keep the car original, you might consider throwing that away and replacing it with a manual choke kit (I believe a few vendors carry those). Thanks for watching!
I may have some work to do on my SD1’s carbs and this video could not be more helpful!
Note the FASD is usually quite reliable and I found my starting issues were more to do with the unit’s exhaust into the manifold and perished hoses/o-rings. Basically, the fuel/air mixture wasn’t getting to the manifold and venting into the engine during cranking! Scary.
Excellent!
Thank you for sharing your expertise.
I'm hardly an expert, but I've done enough of these that I hope I'm being helpful to the community. Glad you enjoyed it!
Well done my friend.....Awesome
Thank you! Hopefully this gets another car back on the road.
Great video and tutorial ! I now have the courage to put new carb parts and clean up the carbs on my 1970 Jaguar XJ6. It sat since 2014 had nasty gas in the fuel filter but luckily the two tanks were clean n rust free.
Thanks , I just subscribed with complete gratitude :)
Glad I could help. I love old XJs! I think my favorite bit has to be the button on the dash to switch between fuel tanks. What other car has that?
Great video! On my Volvo 164 there are two of these, that needs some work. This will help me a lot, even better then the workshop manual i have.
Glad it helped. Definitely reference the workshop manual for the measurements, as things like the float height might be different in your car than in a Triumph. Good luck!
great video I am rebuilding mine on my 69 TR6 ...great tips .
Thanks very much!
Nice and detailed video
Thank you! I'm hoping it helps solve a number of questions that keep popping up in forums.
This is brilliant, I'm struggling to get the needle seat out of the carb damper piston body and was afraid to just pound on it until I saw exactly that at the 8:00 mark. Full speed ahead now! And the expert shop that rebuilt the carbs has blocked off peripheral functions that the owner decided my TR7 didn't really need, so now I see how to put them back to original functionality. Many thanks!
Glad it helped. A hammer is sometimes your friend.... And "expert" is a word that's thrown around pretty frequently.
Thanks for posting this, and explaining everything as you went. I had a 175 CD in a series Land Rover that's had rough starting since pulling contaminated fuel through it. Once I saw you explain how the choke worked I knew that that would be the problem, and right enough the jets were blocked!
Cheers,
Steve
Thank you! I'm happy to be helpful with such a variety of cool cars!
Outstanding set of videos, both theoretically and practically. Thanks for taking the time to do them. Moss Motors owes you.
(1969 Volvo 1800S)
Thanks very much! I'm still waiting for them to send a commission check... :)
Good video! I have this carburator on my Volvo pv and this video Will Come in handy when i decide to clen it, good video for learning since i havent done this before😄
Most of these jobs are actually pretty simple. They don't even take expensive tools. Just some patience and a lot of rags/paper towels!
Thank you so much, was gonna do a conversion because their was no good videos out there rebuilding and I don’t wanna pay someone else to do it. But after this video I’m subbing and so excited to finish my car!
(1969 tr6) have a few videos on my RUclips of it running rough right now all custom color design not another like it, can’t wait to get it on the road!
I love a good TR6! Actually, I think these carburetors are easier to deal with than some of the alternatives. Switching to downdraft Webers is technically worse, and SUs or DCOEs make more work elsewhere or it won't run right. Good luck!
@@midwestmotoring thanks for the advice, I was really looking at all of those options and even ti the point of finding a way to do a four barrel holly or some thing along those lines. But....... this car was my dads dream he hit a stop sign and dented the front up drove it home parked in his garage where it sat for 38 years absolutely ZERO rust. He started to re do it and got it 90% done. White tail, red body, white top, all white interior including carpet. Rebuilt the motor and dropped it back in and it was almost finished just odds and ends left drove it to 1 car show maybe 40 miles on the car in all that time but it’s been sitting for about 8 years again now, so I gotta finish it and go through it so my dad can see it before he passes. Was beyond excited to find this video so I can do it myself and keep the car for years to come. Wish I could send you a pic of it at the car show! But cheers man please keep the videos coming. So much more a lot of need to learn to do :)
midwmotoring@gmail.com is the email. I'd love to see pics at the car show!
This video is a life saver, i got a volvo 140 im trying to get inspected and have to fix the carb on, and this video was perfect nice of you to describe what everything does aswell🙂
There are a lot of Volvo and Mercedes guys that apparently have the same or similar carbs on their cars. Pretty cool how the knowledge transfers!
@@midwestmotoring yep they do, and older saabs have them aswell :)
Truly great video. Great explanations of what does what and what may occur. Just like being there and I agree no blah blah. Just good overview. These carbs scare me. I'd love to send both to you for rebuild BUT I then be faced with the black magic portion of adjustments and such. Also scary.
Thanks
If you haven't gotten around to rebuilding them yet, I'd be happy to help. I'll also send them back with written instructions on the black magic adjustments!
Thanks for the reply. I just had the points replaced with an electronic ignition and coil from pertronics. That’s when this all started. Pertronics coil had to be replaced with a Lucas one ( their suggestion) as it got heated. The Lucas coil seems to work fine but I still have the engine issues when I’m accelerating between 3 - 4 thousand rpms. I got the car in March and drive it often for pleasure. I didn’t have any issues until I replaced the points. The oil is 20w 50 Vavoline which has less than 500 miles on it. Fuel pump was replaced as was several fuel filters and still the same issue. This is peculiar as it runs great than 15 minutes in the sputtering and hesitation starts at the high rpms while accelerating. Also the engine is at temperature before I pull off. Thanks again your feedback is appreciated
I would strongly suspect ignition since you're telling me that that's when the problems started. Petronix ignitions are generally the sort that it either completely works or completely doesn't. A more common fault would be complete failure when the engine gets hot and then starts working again after cooling down for a few minutes. What you're describing sounds like you're not getting sufficient advance or the timing isn't set right to begin with. When a Pertronix module is installed, it doesn't replace the mechanical advance of the distributor. It does, however, add some wires that go inside the distributor that weren't there before. Try pulling the distributor cap and adding a little slack in the wires. The plate the ignition module is mounted on needs to be able to turn 15 or so degrees, and if the wires are holding it in place then you won't get enough distributor advance.
You can test this theory with a timing light too. Plug it in and have a helper rev the engine slowly up to the trouble area at 3 or 4000. Watch the timing mark, and you might find that it only goes so far. If you add some slack into the wires, that could fix your trouble. If not, then I'll bet a weight might be sticking. You can definitely fix this yourself with a little time and a couple screwdrivers, but if you're not feeling up to it I can also clean and lubricate your distributor as well.
One other thing to look for is to see if the Petronix module is working at all at the higher RPM. You might notice that the timing light stops flashing altogether, which indicates your plugs have stopped firing. It could be improperly installed, or it could be just a failing module. They're generally reliable (at least for a while), but even brand new units can be junk. I've had a couple fail in the past, and I suspect it's due to the heat produced under the distributor cap. Others have been much luckier, so I guess it's largely an experience and preference thing. I am running points in my TR6 and have no issues.
Just what I needed for my 1975 MG Midget carb. I have all the rebuild parts but was afraid to tear it apart!
Glad to help! Let me know if you have trouble.
Great, just what I'm looking for.
Don't use a philips head driver in a pozi-drive screw - they fit, but they round-off and strip the head, too!
Definitely good advice!
After you've installed the carborater back in the car, what do I need to know about connecting the throttle cable? Does the engine need to be at operating temperature with the auto choke "off" before connecting the cable?
Unfortunately, I don't know much about auto chokes. I don't think the auto choke mechanism physically moves the throttle. I think instead it creates a bypass circuit somehow to raise the idle, but I could be wrong on that. If it's not connected to the throttle, then it shouldn't matter what temperature the engine is when you connect the cable. When the engine is warm and the auto choke is inactive, you can always look to verify the throttle is fully home. If it's not, it should be fairly simple to adjust the cable, and turn in the idle speed screw at the same time to keep the RPM where you want it.
Good
Thank you! I hope it helps the community!
I'm beginning to believe the kick piston in the water choke does what the the appendage with the diaphragm that keeps the engine from popping during deceleration does- shown about 19 minutes in on this video. They place all enrichment needs; cold start ect. In one unit.
It'd be similar except that it would change the mixture. The bypass valve takes mixed fuel and allows it to bypass the throttle plate at a certain vacuum. The kick piston seems to change the mixture, almost more like an accelerator pump. You are correct that it's a complex device though. Fortunately my Triumphs are all too old to have one!
I had a piece of wire in the head of the metering needle, is it suppose to be there or was it used to temporarily hold the spring in place?
You might mean the piece that holds the needle in place. So it might be that it's supposed to be there... but if that's not it then no, take it out.
Question? Would you want to JB weld the gaskets for the float chamber, etc?
Definitely not. You may need to get it apart again in the future, and the gaskets shouldn't leak if assembled correctly.
Thank you for your very complete and clear tuto.
Do you know where I can find or order the little O Ring gasket you mention at 32'15, please ?
It's for a E Type V12 (looks like the same Stromberg carb). I am in France...
Thank you !
I usually just order my carb parts from Moss or Rimmer Bros.
@@midwestmotoring Thx so much.
Thank you so much for your videos. Could you please help me with two questions? I have a 1968 TR250 and the 175 CD-2 Zenith-Stromberg carburetors have fixed needles and non-adjustable jets. I plan to install adjustable jets -- do you think that installing those will be helpful? The other question may be more difficult. I am having trouble removing the existing fixed metering needles. They are worn and need to be replaced. In your video, you removed the needles by tapping them out with a brass rod. Unfortunately, the hollow cylinder that the needles slide into does not go through (or at least that is how it appears to me and I have found diagrams that seem to show this) so I can't drive the needles out the way you did. Any help would be greatly appreciated. Thank you! Clive
For the first part, yes. I think having the ability to adjust your carbs is important. That said... it's not important if you don't drive very far from home. I only ever adjust my carbs if I'm changing altitudes (such as driving from Chicago into the Rocky Mountains). As for removing the needles, you're correct in your car that the hole doesn't go all the way through. That through-hole was machined in to accommodate the adjuster. I'm afraid the only way to get the needles out if they're stuck is to pull harder (make sure the set screw is removed of course).
I tried giving the wires a little more slack. Although it took a little longer to start hesitating it wasn’t as bad. Am I on the right track? Thanks again
Hi Phil, if the problem got better, I'd go with even a little more slack and see if it helps. The only real way, unfortunately, would be to see if your timing is changing at different RPM. Does the car need to be driving to create the problem, or will it still hesitate even while stopped? If it's acting up while stopped and in neutral, you can pull out the timing light and see what's happening. Otherwise, you could try driving it with a vacuum gauge to see how the needle moves.
Great video. Hoping you can help me with a problem I’m having. I have a 75 TR6. About 15 minutes into a drive the engine starts sputtering and hesitating at 3 - 4 thousand rpms. Know what this problem could be? Thanks
So I'm making a few guesses here. When you're hitting 3-4k RPM, are you accelerating or cruising at higher speed? If it's happening on acceleration, check the oil level in the dashpots. Also, if you have an oil in that's too thin, then it may be even thinner when the engine is warm. That could have an affect on acceleration.
More likely, though, is that your timing is not working as it should. The distributor will advance the timing using a combination of weights and vacuum signals from the engine. If something is sticking internally, the timing might be off at the higher RPMs, which would make your engine run poorly. If you're in the US, I do look at distributors for people and would be happy to make sure yours is working properly.
Other than that, I might suspect a fuel delivery problem. Maybe the pump isn't quite doing its job and is less efficient when things heat up. It could be poor carburetor adjustment as well, as you'd possibly be putting the choke in once everything warms up (though I would expect that to be an issue sooner than 15 minutes). You can pull a spark plug or two to see if that might be the issue, but it's misleading because poor fuel adjustment can still be ignition-related. I'm rebuilding a set of carburetors for someone now and may have found their running issues there.
Driving with some gauges attached would be helpful. Modern cars have check engine lights and sensors, but you can mimic the sensors. A vacuum gauge and a fuel pressure gauge might tell you what you need to know. You can plug them in (I use a t-junction for the fuel pressure gauge so the engine can be running while driving) and put the gauges under a windshield wiper, then go for a drive. Note what's happening when you have trouble. For example, if the fuel pressure drops at 3500 RPM while the engine is stumbling, you know that's where the problem is. Good luck!
thanks for this and other related videos - question - I am rebuilding two 175-CD from a 1975 TR6 - on my carbs, the starter box / choke does not have the spring that is visible in this video, and also shown in the additional video where you disassemble the choke from another carb. I don't understand the purpose of the spring as the choke is manually operated from dash control using a cable to open and then gradually close the choke. Did some versions of these carbs not have the spring, and what function does the spring perform?
That's right, not all versions got the spring if memory serves. It's meant to help the unit to return to a "non choke" position. Older versions had a much stiffer cable instead of the wire strands, and the cable did the job of pushing the starter box into position.
@@midwestmotoring wow - that was quick - I was just about to send a clarification that I was talking about the spring visible on the outside of the assembly, not the internal one that keeps pressure to seal.... but your response indicates you knew what I meant. I can't tell you how glad I am that I found your carb videos for the Zeniths - so much better than the so called "instructions" or diagrams that come with the rebuild kits. I have a '75 TR6 that I have owned for 40 years that I am getting running again (been sitting in my garage for 5+ years) so I can sell it - I plan to use Craigs, Ebay, and maybe British Car Classifieds to list. Any other good places to list? Thanks again!!!!!
Bring a trailer does pretty well, but I don't know about the process or costs.
My zenith stromberg carburetor has a water choke. What is the function of the kick piston?
I'm not super familiar with the operation of the water choke, but the kick piston is basically controlled by engine vacuum, and can somewhat control whether the mixture is enriched or not.
The float seems to be molded at an angle along the bottom side. I'm having difficulty getting it to 17mm front to back.
Front to back isn't important. It's side to side you need to be aware of. You're measuring at the highest point on both sides.
Awesome video!!! maybe you can help me, i´ve a 1975 mercedes benz 230 with a stromberg 175CD carburetor, i´m having problems with the cold start, i really can´t start the car at morning, but the same day after noon the car starts really easy and that happens every day, any chance you can help with this problem, and also i really don´t know what mesure should i buy to change the jet and needle jet, i live arround 2500 meters above the sea level, thank you.
I get a lot of questions from Merc guys, but unfortunately I think the carbs are a little different and beyond my expertise. Sounds like you may have an issue with the choke and not with the mixture, since it works well later in the day.
WoW! You are very knowledgeable on these things... Is it possible to just send a carb to you for a rebuild? A Zenith 175 CD
Yep, it sure is. I do that all the time. The address and pertinent info is at www.MidwestMotoring.com. Turnaround time is usually about 2 weeks including shipping, and for anyone that sends carbs for a rebuild, I'll check the distributor operation for free.
Hi, so I'm having some issues with my carb, it seems to not want to start. once started and warm it runs lovely, if turned off and turned back on within minutes it will be fine, but if left to get cold, the car won't start properly again. I wasn't quite sure what's causing the issue. I've adjusted the main pot needle. After watching your video, I was wondering could it be the bypass valve?
The old carb i had just kept over fueling and pissing fuel out the mouth of the carb. I didn't block anything off but now I'm wondering if something got jammed. These things are older than me so if you could be kind enough to give me some pointers, it would e greatly appreciated. I've been restoring a volvo 244 1979. I've nearly finished the interior, I have an oil leak on a pulley to sort and then just bodywork... well apart from the carb issue :D
Thanks for the video by the way! very informative.
They're older than I am too--I was born in 82. Anyway, I had a similar problem a couple times, and it might not be the carb. Sometimes it has to do with heat expansion and some of the emissions components. Make sure all of your vents are venting, and note whether it happens when the tank is full or not. Otherwise, unless it gets fully cold and then has trouble starting, I'm not sure it's a mixture issue.
Hola. Necesito un asesoramiento. En el caso de este Stromberg con aguja dosificadora regulable. Al cambiarla, ¿también hay que cambiar el pozo por donde se inserta la aguja cuando baja el piston?, como en el caso de los CDS de aguja fija. Desde ya muchas gracias.
No, generalmente no es necesario cambiar el "jet" al mismo tiempo que la aguja. De hecho, generalmente no es necesario cambiar la aguja si no está corroída o dañada. Gracias por la pregunta!
Was curious, i have special tool to remove needle, but the hex tool can only move a few degrees in either direction. Im afraid to really put any muscle in to it. About the 10 minute mark. 1980 mgb
The special tool is not supposed to remove the needle. It's only for adjusting it. You need to disassemble the carburetor to remove the needle, and need a small screwdriver and a long, thin punch.
@midwestmotoring Yep figured that out. Needle assembly was just stuck. Appreciate you getting g ack with me. One more question: Where the throttle blade shaft goes through carb, are those aluminum bushing replaceable? Where the spring sits has worn into aluminum circle. I have the square cut orings and copper washers coming.
Hi there, love your videos! Thanks for such an informative video on taking the carb apart. I do not have the tool you use to take the needle out starting at 6:20. Do you have a recommendation on where I can find that or what its called to order it? Thanks!
Moss Motors has them. It should be somewhere in the carb section on www.mossmotors.com.
@@midwestmotoring Thanks I just ordered one!
On another point, it must be noted that when you removed the carb piston, please note the jet ports adjacent to the needle must face INTO the intake manifold when fitting the piston back into the carb again..
thanks for pointing that out - I am in the middle of a carb rebuild and studying this video and reading comments - it appears to me that when the two little rubber male tabs on the diaphram are lined up with the female indent on carb body and female indent on the piston that ensures the two ports I think you are refering to at the bottom of the piston are facing the intake manifold side - right?
@@MrALBOBALBOB yes.. a reminder, do not tighten the diaphragm cap, the aluminium housing threaded screw holes are delicate. The rubber diaphragm seals good enough..
Correct. The tabs on the diaphragms will only fit in one way, so just pay attention to those if you're not sure.
Question i have same tool to adjust needle but left carb when put tool spin like 5 5 time the right carbs only spin 2 and half before stop on left side and right side what can be?
I'd guess it's the retainer being loose, but I'd have to take apart the carb to see.
@midwestmotoring I'm be able to set carb properly even if that think its loose?
Maybe or maybe not. I would need to disassemble part of the carb to see if it's working properly.
Hi! do you know what kind of oil goes into the carburetor?
The same as for your engine. I have an oil can of 30w in my garage that I use, but you can top it off when you do an oil change with the same oil if you need.
Would you be so kind as to tell me more about the bowl vent tube? I'm helping a friend with his newly purchased '74 TR6 and It leaks fuel out of the jet even when not running. It has added almost 2 quarts of gas to the oil level. The carbs have new float needle valves and they aren't stuck. The floats are not defective and are at correct levels. The vent tubes have rubber caps over them. Is that why they leak fuel and run rich? If so, can I connect them to the air filter? There is no carbon canister. Thank you for any suggestions. Excellent video.
Remove the rubber caps and you're done. If that doesn't work, you have more than 1 issue going on.
@@midwestmotoring You are correct about that, the small electric fuel pump is putting out about 4.5 PSI not 2.5. I will be adding a pressure regulator and gauge to it soon. One last important question: Where should the needles be set initially? All the way down, or up, or someplace in the middle, when beginning to tune? Thank you for the quick reply.
@@novakenss 4.5 is definitely way too high, so you'll need to address that too. Needles should have the base flush with the bottom of the air piston as a starting point, but that's meaningless unless the float height is set properly first.
@@midwestmotoring I put on an accurate pressure gauge and the electric pump is exactly 2.5 psi. No worries. I will change the filters. Floats are the white plastic type and buoyant, level is 17mm, needle valves are new and clean. The culprit like you said must be the fuel vapor tubes being capped off. I'm also removing all corrosion inside. Thank you for the needle position information. Oil and filter replaced. The oil reeked from the 2 quarts of gasoline. I'm going to make Brian, the TR6 owner, join your channel.
Great video! this will be my guide for my carb rebuild. I have a stromberg carb on my Volvo 145 and Im looking to rebuilding it. I want to know what's the difference between a CD, CD-2S and CD-2SE, it's just so I can buy the right repair kit. My one is just a CD-2 and I couldn't find any info online. Is my one a 2S? or a 2SE? I might have missed something. Thanks :D
Thanks, I'm happy someone's watching! The difference is basically the addition of more stuff. Original CD carburetors were much like SUs are. They adjusted from the bottom, had no emissions stuff, and were extremely simple. CD2s added a starter box (the choke) instead of having a rod lift up on the pistons slightly. Then came the bypass valves, then the water chokes, and so forth. I don't know where each of the changes came in, but that's basically how more letters got added. All of them operate on the same basic principle though, and if you have a shop manual for the car it should tell you things like how high to set the floats. I think the rebuild kits are pretty standard too--there are usually a fair number of gaskets that aren't for your specific application left over. Just put on what you take off the carbs and you'll be fine.
I tried removing my float chamber bit it seems to be so hard to take off. There's this brass plug that jas groove for a flat head screw driver. Can i still remove the float chamber without removing the brass plug? Or im still missing another screw so i can remove it easily? I dont want to pry it out, i might break something. Thanks
Hi Joseph--sorry for the delay. Apparently RUclips doesn't notify me except for the first message! Anyway, yes, you can remove the float without the brass plug. You can also take out the plug first (which I find to be easier on my cars). A screwdriver with a large, flat head will do the trick, or you can use a pair of pliers on the plug. So long as you're grabbing it below the o-ring, you can't really damage it except cosmetically. Shoot me a message through www.mwmotoring.com if you have more questions. Thanks!
maybe i missed something but he didn't talk about float adjustments?
Might have been in a different video, but you're right that it's important! Make sure the gasket is out when measuring.
Do you know why the fuel does not go in to the engine? It gets to the carb and then it's just stuck. The fuel line gets so high pressure that when I remove it it spits fuel.
Either your engine isn't creating a vacuum or the carburetor needs to be rebuilt. We do that service if you need, and if you're a member of the channel you'll get a discount as well.
@@midwestmotoring well I live in Sweden, so it's a bit long hahaha. So I just gave up and bought a su carburetor hahaha
what is the size Alan wrench that is used to adjust the needle?? I lost mine and wanted to get something
You really need the special tool. An Allen wrench won't hold the piston in place while you make adjustments and you're likely to damage the diaphragm.
@@midwestmotoring I have the tool as you said that hold the piston in place, I lost the allen wrench that came with it.
1/8 inch allen works on my 175 CD Stromberg, just make sure it's long enough to reach the adjustment screw.
@@denniskwahl I have the tool but can't find the allen wrench.
Where can I buy the tool to remove injector
Might just be a miscommunication, but what do you mean by injector? Do you mean the adjusting tool to remove the metering needle or are you asking how to remove the jet? If you have jets that are pressed in place it is very unlikely you need to remove them unless they're damaged.
Where can I purchase the Service Kit for Stromberg CD 175 for My Mercedes Benz W123
I would try a classic Mercedes parts supplier. Unfortunately I'm not familiar with that, but maybe someone else will respond?
@@midwestmotoring Thanks a lot for your respond .
I have the exact same carburetor on my 76. And very much appreciate your videos. But I have a problem with this one. Maybe you could clear it up for me.
At 20 minutes and 22 seconds on this video you talk about the bypass valve ports on the next video at 12:52 you talk about the gasket your putting on lookin weird but that’s the way it supposed to be.
I believe it looks weird because there should be gasket material between the two ports, the inlet and outlet, otherwise you’re going to be getting air fuel mixture completely bypassing the bypass valve through the gasket gap between the ports. Gasket material between the two ports forces the air fuel mixture to squeeze past the diaphragms brass valve disc and enter the lower port going to the intake manifold.
Evidence of this air fuel mixture bypassing the bypass valve is right on the casting of the carburetor between the two ports and your bypass valve.
No gaskets for the bypass valve that I have purchased have the correct gasket material between the two ports, looks like I’m making a couple gaskets like I did for many years during my military service. What are your thoughts?
Thanks again for all your videos I have learned much.
What you say makes sense, but I suspect it was designed that way. Unfortunately, my knowledge on fluid dynamics is lacking, so I couldn't say why that would be the case. Anyway, at idle the throttle isn't completely closed, so a little "permanent" bypass is just part of that and doesn't have a bad effect. It's the change in the flow that makes the difference.
@@midwestmotoring thank you for getting back to me. I’m going to continue doing research on this and if I find out anything else, I will let you know. Thank you.
Hello MIDWEST
I dessambly my jet for change him and i dont Known the Good rotation for the jet .
You can help me please ?
It is not necessary to remove the jets in most ZS CD175 rebuilds, so I don't do it very often. You'll want to check your shop manual, since there is a specification for where to locate the jets. Unfortunately I don't know what that is offhand. Also make sure you use the proper tool for installation or you can damage the new jets.
@@midwestmotoring thanks
I’ll try to find the Shop manuel stromberg
at 8 mins it seems that you only need an allen hex key and that the only need for the special tuning allen key ... Is tuning .. Is this right as that is when you have the diaphragms assembled not when you are doing it Ta good vid
I think what you're asking is whether you need the special tool for assembly and disassembly purposes. No, you do not. The special tuning key is only necessary to adjust the needle when the carb is already put together. The tool does 2 things at the same time. 1. The barrel of the tool slots into the air piston to keep it from rotating. 2. The allen key slots into the needle adjuster to raise and lower the needle when it's turned. That way you can adjust he needle without turning the air piston... which would damage the rubber diaphragm by twisting it. If the air piston/diaphragms are not installed in the carburetor, then the dashpot isn't holding the diaphragm in place--so you can turn the needle adjuster to your heart's content without breaking anything. I hope this helps! Thanks for watching!
@@midwestmotoring Ta mate Yep this is exactly what i was asking. I have ordered the tool but want to get to the o ring so i can find size and fix. Have 2 carbs sitting on me bench from a TR7
What is the difference between 175 cd and 175 cd-2?
The 2. Seriously though, it's just a more modernized version of the same thing. The carbs are the same size. I believe they moved the choke, and started adding things such as the bypass valve and the temperature compensators.
@@midwestmotoring thanks for answer. Mine is literally looking same as yours in the video (choke,bypass etc..). But on top it reads only 175cd🤔 temperature compensator is white colored and the float bottom is more ”boxy”. Maybe the top has been replaced idk.. i have also seen some 175cd without bypass, temperature comp and with different choke.
Pretty much, yeah. They made changes over time, but I'm not 100% on the CD vs. CD2 if it's not the chokes at least. Maybe later CDs started some of the changes.
Me explico mejor. Al decir el pozo donde se inserta la aguja al bajar el pistón, me estoy refiriendo al Jet.
Gracias! Mi espanol era mejor en anos pasados, pero "Google Translate" es muy util!
@@midwestmotoring Gracias por las repuestas. Saludos Desde Argentina.
my oil leaks out any idea
Yep. The adjuster at the base has an o-ring around it. That's where the oil is getting through. You need to disassemble and replace the o-ring.
@@midwestmotoring I've been using 3 in1 oil in my dashpot with a new o-ring and it spewing out everywhere,obviously too thin. John of University Motors recommends using 80-90 W gear oil in the dashpot...Your thoughts?
80w90 gear oil is the same viscosity as 30w (similar to 3 in 1), so it's not thicker. The oring should not leak with 3 in 1, so something is wrong.
@@midwestmotoring, OK thanks, I'm thinking maybe I'm over filling the dashpot then. I bought this 77 MGB 3 months ago and have been trying to get it roadworthy since. I've gotten it to the point where it will idle on it's own, but if I give it throttle it backfires and wants to die. When it idles it also it goes up and down in rpm. It's turned into my hobby now and I'm having fun while learning.
Hmmm... that could easily be timing. See where it is with a timing light at idle. Then have someone increase and decrease the RPM up to about 3000 and watch the timing mark. It should move one way and then back. If it doesn't, then your distributor isn't advancing properly, which will cause backfiring and a lack of power. The best carb adjustments are always under the distributor cap. Remember that advice and you'll have a reliable MG!
Don’t use a Phillips screwdriver on a pozidrive screw. It is guaranteed to damage the screw. Get a PZ screwdriver!
That's a pozidriv bit I'm using. Good point though, and it can't be stressed enough.
@@midwestmotoring yep, I myself learned this the hard way, experience is a dear teacher. Great video.
At 26.35 you Said not to plug it off, if i dont have a coal canister can i plug it off? Or how would i modify it?
Good question! So in older versions of the carburetor, the vent would go from the float bowl straight into the air cleaner, where it would get drafted into the carburetor. In the later versions (which it sounds like you have), the valve that opens and closes with the throttle just switches between venting to the air cleaner and venting to the charcoal canister. If you choose to modify your carbs, you would simply drill so that the vent to the air cleaner was always open. You could also just leave the vent unplugged and let it vent to atmosphere. That said, you'll still have some problems either way.
For starters, if you have vents on your carburetors, you probably have a car that originally had a charcoal canister. The canister is part of the crank case venting system and also part of your fuel tank vent. Without it, you'll be venting fuel fumes under the bonnet since there's no vacuum to purge the canister. If you have removed the piping that goes from the rocker cover to the carburetors, then you'll also have disabled your crankcase vent. While it still might work (for example with a filter on the rocker cover), it will be less efficient and may cause oil leaks since the build up of pressure will have nowhere to go. The system is designed to have everything work together, so I recommend NOT disabling the venting system. It does not really have an effect on power.
@@midwestmotoring Thanks for a great answer, appreciate it.
@@Splodder glad I could help! In short, the carbon canister is a receptacle for the fumes venting from the float bowls. Once the throttles open up, though, the canister would be purged and the fumes pulled into the carburetors anyway. I think about the only emissions component on a TR6 that has a negative effect would be the air pump they put on later ones. Possibly the EGR, but I don't know enough about how that system works to answer that. Other than that... they really just retarded the timing and lowered compression, but that can be easily fixed by skimming the head and advancing the timing again.