How to increase Performance HP and TQ on a Budget and 350 SBC Chevy step by step assembly tips
HTML-код
- Опубликовано: 24 ноя 2023
- 3 basic steps to improve performance on a budget and step by step assembly of Will Casey’s 350 small block for his 1981 Corvette.
Авто/Мото
So nice to get wise advice from a seasoned instructor.
Nice compliment Mattew. Thanks AG
Ain't that the Truth!
Great content, and tip of the day!!
I was suprised to see that big dent in the oil pan was not dealt with though AG.
Thanks Alleyoop. AG
Great job as always. God bless you and your family
Very nice, thanks Richard. And to you as well. AG
Hey, I really like your show, I think you could get more views instead of making one hour long video make to half hour videos and then once you get your views up and maybe make some longer ones but just some advice not that I know anything but I do know what kind of videos I prefer to watch. Keep up the good work.
Thanks for your comments User. AG
If you put the heads on the block with no pistons in it, you will see that the edges of the chambers are smaller than the bores. That is where the valves are close to the chambers. If you unshroud the edges of the chambers you might be surprised at the free power you can gain
Thanks for the tip David. AG
Nice little engine. Should run strong. I enjoy the longer videos.
Thanks Chad, glad you enjoyed it. AG
Every body has different ways and tricks I like to watch to see if I can pick up something different. I like fitting the timing gear and balancer to the crank before I install,timing gear no problem but balancer can be a problem. I also check pan to pickup with only it installed no crank you can look down the cylinder and see exactly what you have Thanks for your info
Thanks for the tips John. AG
You are correct on the machine shop. It doesn't take long to eat up your budget pretty quickly there. I have an L-31 Vortec there now. To have the block hot tanked and magged and to R&R soft plugs and cam bearings and dimensionally check block and ball hone the block is $400. They wanted so much to go through a set of Vortec heads I just ordered a set of AFRs from Skip White and traded the Vortec cores to them for the other work. Contemplating just ordering the complete rotating assy from Skip White and they will check and size the rods there and the come already ballanced with a polished crank for a reasonable add. charge and just drop it in. At least that way I get a Scat crank, Scat bushed I beam rods, Wiseco pistons and Hasting Rings and King Bearings and a Pro street SFI balancer and Flex Plate for around $1450. If you're not caeful you will spend what you could have ordered a new blueprint engine for. Heck for $4600 you can get a new 4 bolt L-31 Vortec 350 with a 3 year 100k warranty delivered to your house and add a cam and manifold and headers and be done with it. The only reason it went to the machine shop at all was the fact it was an unknown engine with 150k miles on it. thanks for the video.
Thank you Mark for taking the time to comment. Our thinking is pretty well aligned on this subject. AG
MR Gold put a dab of ultra black silicone behind timing tab so they don't vibrate makes keeping track of timing easy . Luv the videos
thanks for the tip and the nice compliment Larry. AG
Looks great so far
Thanks! AG
Like your vids. Keep doing what you are doing
Thanks so much Dennis. AG
I'm going through my old '73 Nova engine this winter. Its just a 2 bolt main block that I'll upgrade to ARP studs. I'm probably gonna order a complete rotating assembly, rather than spend money grinding the stock crank and resizing the rods for ARP bolts. The pistons are always the tricky part of a pump gas street bound engine build. I already have some rebuilt 882 heads that have been modified for up to .500" lift cam. Most stock style dished or flat top pistons won't create enough compression with factory heads. If your trying to use a bigger cam and factory heads, you definitely need to build some more compression into the engine somehow. The only way to do it without zero decking the block for true flat tops, is steel shim head gaskets of .015 compressed thickness with KB domed claimer pistons. The kit I'm looking at should make about 9.5 to 1 compression ratio. With the Comp 280 magnum cam that has .480" lift I should be able to make 300+ HP. Should be plenty for the tiny litte S10 pickup its going in.
Thanks Andrew. Sounds like toy have given it a lot of thought. Planning is the most important part. Good luck with your buils and let us know how it turns out. AG
I remember Car Craft did a compression ratio dyno test on a Chrysler big block. IIRC they were getting around 5 percent increase per point. 9 to 1 was 400 hp, 10 to 1 was 420, and 11 to 1 was 440 hp.
Makes sense Robert. I used 4% because based on our experience. The numbers may vary based on the engine and other factors. AG
Love your channel. Can you please tell me if there's a way to calculate compression ratio on an assembled motor?
Thanks for the question 66. The best indication is the cranking compression pressure. If you know your camshaft intake valve closing point, bore, stroke, combustion chamber volume etc. you can work it backwards to find static compression ratio, or come pretty close. I use the Wallace Dynamic Compression Calculator and Summit static Compression Calculator. Actually cranking compression pressure is more important. I plan for 180PSI max for street pump gas engines. Hope this helps. AG
My quinch I keep at .042 to .046 street performance, and 2 bbl carburator race engine I run between.034 to .044 . As David Vizard said you can go tight as .022 but they made A Lot of desk paper weights getting there.
Thanks Larry, it's all good until the piston hits the head! AG
Built a dirt car pure stock I use .026 mahle gasket the guy's won many times that year they decided to freshen up and put .015 steel shim and shal we say they found out , every piston had exhaust valve contact said it didn't want to turn over very easy , need less to say they brought it back and freshen turned into rebuild .
Thanks Larry, lucky it didn't brake a valve, you know what happens after that. AG
You could have radials the two oil holes in the oil.pump and would have helped it. Also, it should have .004" clearance between the oil pump cover and the gears on the case... AG. What you showed looks like the pump gears were running against the cover because the dist. was too deep in the engine trying to drive the gears out of the oil pump.
Thanks Leonard. That was the original OEM pump assembled by GM in 1981. Some wear on the thrust plate is normal and will not hurt performance. AG
when it comes to chasing compression, it's good to remember as you said, a full point increase is "only" 4% power increase--so how much does one want to spend to get 4%? (anything less than 10 bhp rarely is felt by the "butt dyno"). A pair of poor-burning cylinder heads (on a budget build, compared to say Vortec heads) might want more ignition timing and so having a relatively lower CR to allow more timing on pump gas might pay off. And then there's the wear in, as 'rings and/or valve seals loosen up, letting some more motor oil into the combustion chamber, a lower CR may offer a tuning cushion.
If we begin with a complete engine, get the pistons at all four corners to TDC and measure their distance from the deck--this can tell you if you need to get the block decked because things are way too off. some will reassemble with an "overthick" rod bearing on the 'rod side and an undersize (by the same amount) on the rod cap side, to shift the connecting rod higher up the cylinder, if a thinner head gasket worries the customer. If the builder wants to get fancy, some will use a higher intake rocker arm ratio on the outside four cylinders since the intake runners are longer and so the air/fuel mix takes longer to reach them than the inside 4 cylinders, but that depends on intake design (port fuel injected engines of course aren't having this issue). this may help give a "high compression" cylinder get the fuel to burn on outer cylinders rather than try to melt their aluminum piston, and play with spark plug temperatures since octane defines the length of burn.
if someone wants to chase high compression on a budget, they better have a spot-on way to measure CC in each piston and combustion chamber in the cylinder head, and know the crush thickness of the head gasket they're using. A cheap way to increase CR is to find a Vortec 305 head that isn't cracked. the smaller ports won't help hp at high RPMs but for street driving with an overdrive transmission and the right rear gear ratio, it can help with fuel economy.
good point about the piston rings--I like to use a fish scale when pulling the piston combo into a cylinder rather than tap it in, if i get a reading different from the other cylinders, i know i have a problem. easy to catch and fix at that time.
some builders will mix and match big block oil pump parts with the small block, but the thing to remember, don't use a high volume pump with a stock oil pan--you'll just empty it out too quick. Chevy used basic pumps with different springs for their engines designed for high RPM (the early Z28 stuff meant to be raced). Cleaning up the passages will reduce interference and help the oil get out, and sometimes that will be enough without having to go to a high-pressure pump on an engine design with a great oiling layout.
Thanks for all the helpful advice Albert. AG
305 vortec heads down pretty much 20+cfm compared to 350 vortec across the entire rpm range I just don’t think it’s worth it if someone is buying heads the 305 heads will be maxed out not leaving room for any future upgrades. The 350 heads can be worked some as well but in reality you can buy cheap Chinese aluminum heads for 400 bucks and work them and install your own hardware and then have heads that are pretty much as good as any manufacturers make flow wise and for less money.
@@Thumper68 agreed, 305 Vortecs aren't a great choice, they often crack between the 'seats. but that's the point with going cheap (versus affordable), you're giving up some benefits. the problem with the cheap ebay "chineseum" heads has been covered on video channels that deal exclusively with head porting (pisscutter, erik weingarter, etc). some will have porosity issues at operating temps, or the casting has sand core shift issues, or quality control on the valve seat areas, spring pockets, and other spots is so poor the head has to be rewelded and remachined before swapping over valves and deburred rocker arms (springs likely shouldn't be reused, you may want a better valve guide and seal installed, but a used Vortec head is going to have similar costs too) .
not all are like this, and of course there are people who run into similar QC issues with Edelbrock heads and carbs, so i'm not trying to make a case against what you suggest. far easier to weld up an aluminum head (but a pain to mill and machine, aluminum really fills up a grinding bit) and there's benefits to aluminum (if one knows how to lash the valves properly for aluminum's expansion rate). detonation resistance, weight, etc.
as we all know, being cheap is a roll of the dice--sometimes it pays off big and sometimes we total up the bill and realize we should have paid more up front.
thanks for contributing to the discussion :)
@@albertgaspar627 I agree on all those fronts. Your response is exactly what I expected I also watch all those same channels.
I do think that there’s better sellers to buy the Chinese heads from to get better castings though.
Even though they are only 305 Vortec heads they still out flow conventional SBC heads by a wide margin. I like that trick about using thinner/thicker connecting rod bearings to adjust your deck height! That never crossed my mind.
Hi Allan, really like your show. I have a question. I am building a 1971 sbc 400 4.185 bore. Standard deck height and was already bored when I got the block. Trying to do this on a budget so I don't want to have to get it decked. My piston rod crank measurements come out to be 9.005 and deck height is 9.025. That leaves me .020 below deck. My question is can I use a .020 or .025 head gasket to get my quench. Trying to find out if this will cause any problems on this 400 and if I can get a good head gasket that is that thickness. Let me know what you think and If I have to I can get it 0 decked and then use a head gasket to get the quench.
Thanks for the question Patrick. Cometic makes a .028" MLS head gasket. That would give you .048" quench. Maybe not perfect but acceptable. I think you will be fine with that. There may also be thinner gaskets available. I suggest also that you mock it up and actually measure the deck height to confirm your measurements. Hope this helps. AG
🦃 HAPPY THANKSGIVING 🍽 !!!
Thanks Jimmy! and same to you! Thanks for being a supporter!
How do u calculate cylinder pressure from quench & compression measurement? Or where can I look this up? I know how to measure & calculate for compression, but I just do a compression test to find cylinder pressure? I'm unaware of a formula to calculate it??
thanks for the question Jesse. Summit has a great on line calculator for compression ratio. Wallace has a good one for dynamic compression and PSI cranking pressure. Just google it and enter the values. AG
Where did you get the engine build spreadsheet to record all the clearances please? Thanks
Thanks for the question BigAl. Just an Excel spreadsheet that i created. I will put up a screenshot in a future video. AG
Allan, I am using that same set of pistons, but my piston and rod combo is 25 grams less each than the stock L98 (IROC Camaro) pistons and rods. Did you have this problem? Is this 25 grams less gonna cause balance issues for the crank? It's a truck engine that will probably never spin 6000 rpm.
Thanks for the question Lee. Following is how I think about it.
First if you have any imbalance, better to have the pistons lighter as yours are. Also 25 grams is only about 2% of the total weight of the piston and rod.
A reciprocating mass like a piston, with the forces of combustion acting on it, is never really in balance, compared to an electrical armature or fan impeller where the forces are tangential.
Especially for a street engine that spends most of its time under 3,000RPM you will be fine.
When is the last time you saw a crank break in a street engine? AG
The chain should stretch around 3° after running the engine... AG
Thanks Leonard. AG
Will the compression go up after 5000 miles when the rings are totally broken in?
Good question Steven. Not very much. We consider the rings broken in after 3 pulls on the dyno. You can check it and find out. AG
The 1/2" head bolts are torque to yield, the 5/8" head bolts are the traditional head bolts... If you didn't know that you better check into it so you understand and know your heads are torqued correctly...
thanks for the comment J.AG
I agree too long a vid I kinda shy away from
Those GM lifters with the "cap" are the only lifters i would use, comp cams make some "copies" but i would only use the GM lifters...
Summit Compression Calculator for compression. Google Wallace Dynamic Compression Calculator for dynamic compression and cylinder cranking pressure. AG
@@goldsgarage8236 I think you replied to the wrong person...
Allan - On more that one occaision you refer to the distributor of choice you use for your SBC builds. What brand are you referring to? I'm looking for one for my 383 stroker. Thx Al
Thanks Al
Bravex Super High Performance HEI for Chev Big Block and SB Ready to run. With Melanized gear. They are on Amazon. AG
They have them for other engines as well. AG
Thanks!@@goldsgarage8236
As a new subscriber who stimbled on your site, I really like your no nonsense approach to building engines. On a related topic, I installed a BP 383 in my Corvette a ffew years ago, and have been running it without vacuum advance per their instructions ( I see GM recommends doing the same with their crate 383) Why is that? You mentioned in a video that it causes hard starting, which has been the case sometimes. My 383 has gobs of power. so, I'm at a loss to understand what vacuum advance really does. Thanks.
Thanks for the question Al. This might be a good subject for a future video. i will get back to you soon with a detailed response. AG
Do you build 100% Chevys or do you work on other stuff occasionally?
Thanks Brian. i do a lot of Chevy's because that is what customers ask for but I have done Pontiac's, 6 cylinders, even and Austin Healy. I would love to do a Ford or Mopar. AG
Where did you get that pushrod tool? I've been figuring out pushrod length usiing Straub Technologies method.
Both Amazon and Summit have it. AG
That "tool" does not take valve lift into account. Straub's method does.
That "tool" does not take valve lift into account. Straub's method does.
@@jeffreydurham5342 I knew it was too good to be true 😄
Cylinder pressure can always be increased by running a narrower LSA
Actually it's the other way around. Wider LSA makes for higher pressure, narrow LSA is for overlap, scavenging of cylinders, and midrange/higher RPM power.
@@erikturner5073 An engine will have more cylinder pressure with say a 108° LSA verses a 112° LSA. BTW this is a friendly disagreement. 😆
@@rogerstill719 there's no argument. 😉, no need to be afraid.
Probably and running a wider LSA bleeds some off?
I like your videos and the information you give, but please get a lapel microphone! I have such a hard time understanding you over the reverbe in the audio of your videos.
Thanks for the comment PJ. I did have a microphone and we did a sound check. We will work on the sound quality. AG
@goldsgarage8236 Wow, I thought that you were running on the camera microphone. I hope you figure something out because I think the information that you have to share will be valuable for future generations.
Maybe a different style of microphone with noise canceling would help.
I have trouble picking out individual words when I am talking to people in places with lots of background noise, like restaurants. The reverbe/echo in the audio of this video was giving me a similar effect.
The stock balancer has slipped. And please stop right now and change out the timing set so you and properly set cam timing. Those 2 degrees can have a large effect on power curve.
Thanks Dennis. AG
Good info..but this is video format. Talking you can do in a podcast. Show what you are taking about. Then we get better understanding. Keep up your good work.
Thanks for the comment, we will work at getting better. AG
on the subject of compression...how would a person go about determining deck height of a block that you know has been decked - but don't know by how much ? To get the desired compression ratio, how can one order pistons, head gaskets, etc or do the "math" if the factory quench distance is gone? really enjoy the videos! thanks in advance...
Thanks for the question Job1, actually a lot of questions. I will make a video about all this in the future but for now i will do my best to answer your questions.
First, the OEM spec for a SBC for deck height for example is usually about .035". Often machine shops will deck the block just to get it flat and square so they will only remove .005" or so.
To determine your deck height first you need to be sure the piston is at TDC. The most accurate way to do this is with a degree wheel and a dial indicator, but if you don't have a degree wheel the dial indicator will be close enough.
Set the indicator up in the center of the piston and rotate the engine slowly to determine TDC.
Now that you have TDC, there are a few ways to measure deck height. I use a depth micrometer, zero it on the block and measure as close to the center of the piston as you can.
If you don't have one, you can use a straight edge across the top of the block and feeler gauges. If you do it carefully you should be able to get close enough.
Check all four corners, #1,2,7,8 pistons until you get consistent results.
Now add your deck height to the thickness of your head gasket and you have your Quench.
One way to improve your quench with stock deck height is with thinner head gaskets.
OK, now to determine compression ratio. You need t know your bore and stroke, deck height, combustion chamber volume, piston dome volume and head gasket thickness.
Google Compression calculator and enter these numbers. The Summit calculator works well and is easy to use.
Now google Dynamic Compression Calculator. Wallace has a good one. Now you need to know the intake valve closing point of your camshaft to determine your dynamic compression and cranking pressure PSI.
For a street engine I like to be 160-180PSI, closer to 180 if you can get there.
Now you select your parts or combination of parts to get the result you want.
when the engine is done and broken in measure your compression cranking pressure with a gauge to verify that you got it right.
Hope this helps. Let me know if you have any more questions and watch for future videos on this subject.
AG
@@goldsgarage8236 thank you very much for taking the time to respond. That is a very helpful! In my case I know the block has been decked but I don’t have the pistons (I am ordering a stroker kit ) and trying to determine what to select regarding dish size to get around 10:1. Is it best to err on the bigger dish size just to be safe and use a thinner head gasket after things can be mocked up?
Glad it was helpful. Take it a step further and calculate your dynamic compression and cranking pressure first. The deliverable is cranking pressure. You can play what if's with the algorithms until you get the result you want. Don't guess! AG
Not pushrod tool... SILLY ME!! I'm referring to the rocker arm replacer😂
Hi Al,
Love your videos, but I had to stop watching this one because I really couldn't hear you. Pretty sure you had a lapel microphone in your other videos.
Bart
Thanks Bart. I did have a microphone and we did do a sound check. Sorry you couldn't hear. AG
R is spelled wrong, phone done it AG
Hello Sir! I'm in Houston Texas and I'm having trouble finding a reputable Engine Builder. Can I have your email address to send you some information about this Engine Builder who claims to build good Engines. "Gordon Engines " . I want to make sure that the parts that he uses are good quality parts.
sure: allangoldconsulting@rogers.com
This channel is great, I love this stuff eat it up you are very knowledgeable but having to skip to 2;30 to avoid the subscribe to me Jedi Mind Tricks. JC this must be Canada "USA'' doesn't beg like this. Lol lighten up and when you stop asking, we will click it. Just a brief "Subscribe you bastards and send money if you can!" would be sufficient and we won't spend all the time hearing the voice of The Peanuts cartoon teacher flow through our minds over and over. I'd love to see you build a sbc 302 or that set up for the highest rpm ever recorded online that would send this channel to the moon! I'm a Dick, but it works for me. Thank you for all your hard work.