SDPC Tech Tips: SBC Vortec Coolant Bypass
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- Опубликовано: 9 сен 2021
- Nick goes over an important aspect with the cooling system that can be easily overlooked when going from an earlier SBC 350 to a Vortec, or swapping components so you don't end up with one big paperweight.
EDIT: Nick points at the Fuel Pump midway through the video and says Oil Pump. That was a gaffe and we blame it on the heat as the shop was an oven that day.
#SDPC #SDPCRaceShop #SDPCTV #TechsualHealing #SBC #Chevrolet #SmallBlockChevy #Vortec 
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The reason we are going back to small block is the LS engines either leak oil out of every orifice or they are equipped with cylinder deactivation Afm system that are prone to cause early failure. The reason we are going back is reliability
L31 Block is the Vortec 350, I have one in my 99 Tahoe. The L31 block does not have the bypass port and uses a different water pump than engines with the bypass port. The Vortec heads do not have a coolant bypass provision so keep that in mind if upgrading to Vortec heads and you have the third port on your block. Thanks for the video
Drilling a hole in the thermostat is to help bleed the air pockets out of the block after draining the cooling system. That way while you are filling the radiator back up you don't have to wait for the thermostat to open and suck the radiator down. An 1/8" drill bit works just fine. Just my 2cents worth thanks.
Thanks for the information I didn’t know that. After going through all rebuild hours and money i don’t want loose time and money over a $2.00 hose and clamps. I’m two days older than dirt, but never to old to learn something new. Keep up the good work guys
Man I'm only 28 but I've been messing with these engines for about 10 years, done many water pumps and I've always wondered what that third hole was all about ever since the first water pump I changed. I've got a rebuilt vortec im about to put in a truck and it's my first vortec so this video just helped me out alot. Thanks for the knowledge.
Very helpful! Thank you. I just purchased a 350 Crate Vortec and that was the exact question! Thank you!
cool vid bro. i built a 5.7 merc cruiser boat motor and put it in my truck, it had the 3rd internal by pass, but the vortec heads and water pump didnt use that application so we just apoxied it shut on the block. i havnt had any over heating issues so far . going on 2 years now running. so this is what i did in case any one wants to follow suit. the motor as i said is a 350 merc cruiser boat engine i put in my 98 k1500. i used 5.0 vortec heads. big roller cam, roller rockers and lifters, up graded the fi system and as i said earlier, when we were building it we noticed it had that 3rd bypass. we apoxied it and no trouble so far
Awesome videos as usual. I've got 4 sets of vortec heads. 5 880 blocks. So far so good.
Very useful information. Thank you so much for the heads up!
Great vid. Looks like this should solve my issue on my 86' block.
Drilling a couple holes in the thermostat is a common thing done to big block Chevy’s for years as I have done on my turbo 555 to avoid the using external hose and works great so can’t see the problem on a vortec
Came across this and it may be the solution to a problem I’m about to tackle at the shop thanks for the info hopefully it solves a problem
I’m feeling alone out here building the old school engines, hard to find people still doing it, I’m currently building a 86 C10 Stepside 350 with a 142 B&M supercharger, (yep it’s B&M) I had to give you a follow and the bell is on, This is the 8th one I built to show as a everyday driver and do a documentary on it..but hey them are great tips on the cooling.. great video and thanks for sharing with us 👍
this video probably saved me a lot of regret. thank you very much for making it.
Thanks for posting! Been scratching my head for a week over whether my 350/330 turn key has internal or needs external. Maybe just making more work for myself, but taking your advice and running an external just in case.
I've always drilled an 1/8" hole in the thermostat to give just a slight bit of flow "bypass" during warmup. Works great and never had overheating issues
I've always put two 1/8" holes 180 apart.
marine and industrial vortecs also have this bypass. they also have all of the original style steel timing cover bolt holes drilled and tapped.
Old school 355 with double hump heads single plane with a 750 carb simple and still looks good 👍
outstanding! good info
Wicked informative last thing you need on a vortexc swap is a over heat problem to drive you Cuckoo. Thanks
Ooh.. had to go look at my new project block. I must have one of those performance crate version 880 blocks. It has everything. 4-bolt, fuel pump provision, the coolant bypass...
just learning the Vortec motors thanks I would have just pluged it
880 casting vortec 5.7 came with the internal bypass and are drilled for a fuel pump rod. Usually found in 1500’s with the engine code R .
ok i have something to add here.
i have a vortec 5.7 block and heads and a 1994 s10 blazer its squarebody last year. it had the bypass on the block but nothing on the water pump.
i have the 5.7l water pump and it did have the outlet and 90* coolant elbow that always leaks.
i reused the s10 water pump and capped the port on the intake for the coolant.
i use electric fans and a thermostatic switch to turn them on and have never ran it hot per say. has it gotten warm barely. but 90% of the time it runs cool. too cool. like replace the temp sender cool. when it had stock motor same thing it was always cool. i think im gonna swap pumps soon and see if it keeps a consistent temp finally.
for anyone with a similar experience. it has been reliable as heck for close to 30k miles so literally no problems other than too cool.
So the external bypass is essentially the same as what the big block used since the 60s? Would a heater hose going from the manifold to the heater core, and one from the water pump to the heater core, not do the same thing?
I’m not sure I’m having this issue myself right now building my l31 vortec I have a heater core in my cutlass and wonder if running that to the intake normally would keep the engine cool and use that as a bypas instead of drilling holes in the t stat a motor needs to get up to operating temperatures
@@rockfordhx2768 if you only drill a single small hole in the thermostat, it won't have any issue getting up to temp and staying there. I use just a single hole the size of an uncooked spaghetti noodle. Smallest bit I have. It still operates like normal. Using a heater hose going from the manifold to the heater, then heater to the pump should be ok I would think. It works fine on the big block when using the bypass hole on the manifold to go up to the heater instead of directly to the pump?
I'm a old school mechanic, I started with a Chevy dealer in 1966, I always put a hole in the thermostat to bleed off air, we use to get thermostats with holes already in them, I don't recall if they were OEM thermostats. Never had a problem with this doing this
About 15 years ago, I did a vortec head swap on a 1991 c1500 TBI engine. I tried several different thermostats and it would just run hot, the thermostat would never open. Without a thermostat, it wouldn't overheat, but barely moved the temp gauge. I know it's not ideal, but I ended up putting over 100,000 on that engine with no thermostat and no problems, but no heat lol. Wonder if this was the problem?
I have a 88 Camaro with a vortec 350, but with TBI heads and intake. So far so good on overheating. Had issues with heater though
did you just have the vortec kicking around and just used the shortblock Or? shot yourself in the foot with the tbi heads
@@matthewgraham2129 well it was in the car when I got it. Did some research on the block numbers, but I do have 2 sets of Vortec heads and a vortec short block that I’m building.
@@deviantrebel6326 88 Camaro was an LT engine, not a Vortec.
I've had guys tell me I was full of it when I told them they had to drill this bypass hole if you put a virtec engine into there tbi trucks as the tbi trucks have the bypass hole built in to there water pumps. And if you use a pre vortec block in a vortec truck, you can tap this bypass hole with an 1/8" npt, and plug it.
I have an old school Chevy 350 built out to a 355 using the 062 casting vortec cast iron heads. As I understand, the water jackets walls are thin and can cause cracking. My question is what antifreeze do you recommend using to cool with these vortec heads?
They are flat out tougher than the LS. Not my opinion but it’s what I see in here from fellows that I know that drag race.
Good info i was wondering about this as when people are going to use an oem serpentine system on a gen 1 sbc like i want to do ........that bypass hole below the water pump has to be plugged or coolant will pour out. I heard about drilling the thermostat...you seem to raise an eyebrow slightly as maybe its not enough to do only that.
Ah-HAAA! So I picked up a great deal on a 57 Chevy two door hardtop years ago with a mystery engine and been putting a lot of time and money into it lately. Ran numbers today and found it has a 87 vette L 98 block with 96 vortec heads. Just like you said, could not figure out that extra port on the Chevy performance intake manifold. It was blocked off and I was having all kinds of problems. I will chase this down tomorrow!
87 Vette was an LT engine, not a Vortec.
@@TOMVUTHEPIMP It's an 87 block with 96 Vortec heads.
@@TOMVUTHEPIMPREAD THOROUGHLY BEFORE YOU COMMENT!!! SMMFH
@1mattbutch You put that in your comment originally. People are so quick to check someone about something, and they can't read for sh@t!!!
@@grandam haha! Well, calls himself “KING TROLL”! Obviously, just a little kid still developing his reading comprehension skills. Or at the very least is intellectually challenged.
Am I right by saying that you could have either a bypass hose from water pump to intake or thermostat with 1 or 2 holes drilled in them, or both of these options? I'm trying to do away with a hose from WP to Intake and plug the ports.
I have that same Edelbrock Performer intake with that threaded port available but unused. It came on a Vortec Crate motor with the added "third hole" port on the water pump.
Wouldn't it be a good idea to double up and use the third hole AND the added port on the intake?
I have an 87 to 95 block 4 bolt 1 pc seal and has the extra hole and I'm using 062 heads. Can I use the 96 and up water pump serpentine setup? I'm also an air gap intake.
Recently inherited an 84 Elco from my dad. Has a 383 ...edelbrock everything. He always complained about dealing with over heating. I see where the heater hoses connect but there is no bypass....just plugs in the water pump and intake. And there's no hole in the tstat. I should probably run that bypass anyways huh?
You guys need to make a aluminum marine intake for the l31's
My 1998 l31 doesn’t have a coolant 3rd hole bypass I have a 880 block with 062 heads I wonder why I took the water pump off today it’s the normal 3 hole on each side of the pump
Any advice for this Vortec bypass with an electric water pump? Have an 1985 Jeep CJ7, Vortec long block RPM Air Gap like in the video, but i have no bypass port on an electric water pump to connect to the front facing 3/8NPT port like described in this video. I want to use factory heater core as well. I have spliced in a cheap aluminum coupling to lower hose, with a sensor port drilled out bigger and tapped for a 1/2npt to 5/8 barb. I plan to connect it to 1 port on heater core, and then other port on heater core to 1 of the 4, 1/2npt ports, or the front facing 3/8npt front facing port, on the intake manifold. Anyone see an issue with this? Routing these hoses currently so nothing is permanent yet. I would like something a little more reliable than a few holes in my thermostat.
They are going back because they are becoming extinct. Where I'm from everyone pulled their old school 350 to drop in a LS. The LS motors have their own unique sound BUT they will never have that ol skool hydraulic flat tappet sound.
Hello, i hav a slow antifreez leak in my 2005 vortec, gmc denali, maybe a head gasket, amd this tank is cracked??? A mechanic says this iz the seal . It feels like a crack on top of tank near cap...
Could i use the front 3/8 port for the sensor and run the top 1/2 port to the water pump or do i have to use the front 3/8
I have a question I have a 1994 Chevy Silverado K 1500. 5.7 leader can I take A rebuilt 350 out of a 69 Camaro and bolted up my head and intake off my vortex while that work
Those are the best always will be.
I have a gen 1 small block with new GM performance Vortec heads, Edelbrock performer intake. During flat tappet cam break in water temps were near 220-230 degrees. I kept a water hose on the radiator to keep it cool. It is my understanding that the Vortec heads do NOT have the bypass hole drilled in the heads. Making the Gen 1 water pump bypass hole worthless because it is blocked off by the head. Would adding the bypass from the intake to the water pump eliminate my heating problem? I assume it won't hurt.
too bad no replied to your question. I am about to install a similarly build engine and it would be great to know the answer so I can avoid any possible problems.
@@Gords_Garage_AB most Vortec manifolds have a small bypass port in front. Plumb this to the water pump. Othere have punched several holes around the perimeter of the thermostat flange to accomplish the same thing. I plan to use the bypass hose when I get back to my hot rod
I have a 350 vortec also..my Temps while cruising would run around 200°then jump up to about 230°..I put a bypass hose from the top of the water pump to the hole right under the the thermostat on the intake and now I run at a consistent 180° while cruisin and around 190°-200° at idle
@@jameshardy8797 Thank you for posting James! I'm working on a 1950 Chevy COE but will get back on my Model A with that engine soon after
I have an 87 tbi truck that i am installing a new l31 350 with the tbi to vortec intake conversion. Would this require the external bypass? The heater hose run from the back of the intake directly to the radiator unlike the earlier 350s that ran back to the water pump. Isn't the heater core acting like a bypass?
The heater does not act like a bypass, you will still need to run the bypass on the front of the intake to the pump.
@@Sdpartscenter Have you found any good ways to do this with the original water pump from 87?
@@Blakep7704 87 must've been a damn good year for water pumps if she's still going strong!
If using the coolant by-pass port on the front of these vortec style intake manifolds like the one he displayed in the video, how does one route the heater hoses to have a functional heater? I'm assuming there's a certain water pump that can be used for this application. Wanting to run a V belt water pump, not serpentine.
3 way outlet for intake bypass hose to water pump and heater hose
@@biscowild4949 Thanks. The only three-way water pumps I found were either older short-style pumps or the vortec truck pumps which are huge and don't look right on clean SBC hotrod. I ended up using a standard Chevy long pump. I'm just letting the water flow through the heater-core as a bypass when the thermostat is closed. I also drilled a small hole in the 180 degree thermostat to keep a little water passing through. So far, so good. Doesn't overheat or puke water etc.
So it shouldn't be a problem putting a vortec water pump and serpentine system on an older block as long as the external bypass is hooked up like it it would have been on the newer engine?
Where is the best place to find vortec l31 performance parts? Jeggs? Summit? Paw?
Say Brother..which water pump goes with that engine..I seem to can't find the 3 hole pump
5:35 he means 'fuel pump pushrod hole'.
At 5:37 that is the fuel pump pushrod, not the oil pump.
What if you put Vortec heads on an old school small block?
Ok. Might not plug the hole now and try to just get the pulley from the junkyard for my older pump.
I want to install an electric water pump and the bypass needs to be blocked. What should I do?
How about showing what you recommend we do? Drill the missing buypass hole, in the block? Run a hose from the intake manifold hole you pionted to the the water pump? If so, please show where in the pump it should connect. Thanks
Run the hose from the intake to the water pump..it works
Can you be more specific, for those without first hand knowledge of the fittings. Which intake manifold fitting to which location on the waterpump, Thanks. @@jameshardy8797
Vortec bypass is like a BBC bypass . Coolant has to keep moving. My 880 block reman engine has that hole in block and a 95 638 block has the bypass hole in block.
What if I have a gen 1 sbc with vortec heads?
Awesome video, I'm stuck with my 5.7 vortec carb conversion, don't know where and what to plug on the intake manifold, and what vacuum lines go where? Do you have a diagram for the intake manifold and what size the thread and pitch is for the bypass fitting
I got a second gen Camaro a 1980 Z28 Camaro I'm trying to look for a good motor
YOU HAVE A GOOD MOTOR, THROW SOME VORTEC REBUILT HEADS ON IT AND AN XE268 COMP CAM, YOU WILL BE PLEASED!!
Or did it come without an engine?
I drill the head to make the internal bypass open
Just did one today infact
People aren't "going back" to the sbc. Some people never left. The LS is meh.... and fugly... and the SBC can still do the job.
Yes the LS is better....
Mine L31 HAD THE JUNK PLASTIC INTAKE AND INJECTION SYSTEM AND IT CAUGHT ON FIRE AND I ALMOST LOST MY CAR THANK GOD I DIDNT NOW IM GOING CARB AND INTAKE SHOULD HAVE TO BEGIN WITH VERSUS UPDATING INJETORS NEW FUEL RAIL GOING IN AND ALL SEALS FOR NOTHING IT MELTED THE INJECTOR PLUG OFF WHEN IT POIRED GAS ALL OVER MANIFOLD NOW IM DOING IT RIGHT
Yeah well some of us can afford old school!!
What the fuck is scoggin dickey
Very uninformative no bypass there bud.
Fuel pump pushrod hole.....good info though.
That hole is there so the heater will start working while the engine heats up, instead of waiting for the thermostat to open. Plug that bitch and move on for performance apps. I've done it to many builds. Most aftermarket electric pumps don't even allow for it. just my .02
Thanks. I'm betting you are right and this video is wrong. Mostly because he did not give one valid reason (that I heard) how that bypass is going to keep you cooler. Doesn't a bypass cause hot water to "bypass" the radiator and go back around the system? Your version makes a LOT more sense.