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Small block Chevy endurance racing failures.


Indysupra
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I've been racing SBC since the very first Chump Series race. I've encountered about every type of failure possible. 

 

Once I decided to run a factory Roller cam engine and had every rotating part balanced my failures stopped. 

 

I run the engine to 6 grand every shift and do not use the engine compression just braking for down shifts. Engine now stays together.

 

Hope that helps

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On 8/18/2019 at 5:48 PM, Indysupra said:

What types of issues have you all had with endurance racing a SBC. Don’t expect people to give up the secrets on the fix but just curious of problems. 

 

Been running SBC's for almost 10 years in Chump, usually 2-3 events a year. NEVER scattered a motor. Ever. (find me some wood to knock on...) Lincoln motor was stock iron-head Vortec, original motor was literally 200k+ miles (only thing we did was change valve springs) we decided it was tired and bought GM long block, was amazed that really all it would have needed was a valve job, bottom end was pristine. Camaro is stock LT1, rebuilt. Super big fan-boi of Amsoil, only because of some poor decisions and precarious things we've done over the years and never had any oil-related failures (like run 21 hours @ VIR with a broken oil pick-up...).

 

Only time we've had any mechanical parts failures is when we've used anything Chinesium. Stick to quality OEM/OEM-equivalent US sourced fasteners and parts and you will be fine. Keep it cool, run a pan with some sort of basic oil control, and probably an oil cooler. We never ran an oil cooler on the Lincoln, but I put one on the Camaro. Not sure if we really need it but it certainly can't hurt. Never shifted beyond the mid to upper 5k area (runs out of steam with a stock cam anyways...).

 

Nothing really to talk about privately, but feel free to PM if there is anything you don't want to post in the forum. To be quite frank, I really don't know anything special. 

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4 hours ago, pintodave said:

Only time we've had any mechanical parts failures is when we've used anything Chinesium. Stick to quality OEM/OEM-equivalent US sourced fasteners and parts and you will be fine.

This is sage advice. We don't skimp on fasteners, fluids, replacement parts, etc.. When we assembled the long block, we used ARP fasteners on everything. @MoparBoyy uses all good fluids/filters, etc.. 

FWIW...this is our SBF. 

See you at Sebring!!! 😜

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our 1st 305 took the course with 149k on the clock. All we did was change the time chain, added a cam, larger oil pan w/ trap doors after the 3rd race, headers remote oil filter and used good oil. That engine lasted about 6 weekends and some "testing" here and there. It ran great all day Sat at an event, then start up Sunday morning and it had a rod knock.  the new engine is a 88 roller 305 (129k), we did some head work, again changed the cam, t-chain. This motor got all new rings and bearings...good ones not the cheap stuff. It runs killer. It has about 2 weekends on it.  The only down side to the roller motors is compression. The pre-rollers are like 9.5:1 and use flat-tops.  The rollers are around 9:1...maybe a tad higher w/ a dish.. 

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21 minutes ago, TiredBirds said:

  The only down side to the roller motors is compression. The pre-rollers are like 9.5:1 and use flat-tops.  The rollers are around 9:1...maybe a tad higher w/ a dish.. 

 

If you have a milling machine or know anyone with one, you can cure that....

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Remember that engine mods are value added here in this series. Swapping parts of compression change is a mod. Do what you think you can get away with of afford with you budget.

 

Back to what I originally posted. Oil is huge. I used Total high zinc oil with the non roller lifter cam then when I found the factory roller engine I went to the Total synthetic. Best decision ever. 

 

Compression swap is easier to swap heads than to machine plus cheaper. Push rod/rocker alignment is critical while sustaining high rippems. Slowing the water pump/power steer pump is also important. Plus I only use Stewart brand water pumps. 

 

My weirdest fail was from the little assignment pin on the front of the cam shaft/pulley pushed it self out into the timing cover and deposited fine metal shavings into the pan and bearings. Wiped out all the bearings. 

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Are you running an 88-92 Camaro?

 

I dumped the tune port intake just to make life easier. Removing the intake quickly is a hassle to do a repair. We broke a rocker arm and a lifter came out and had to pull the intake during the race. Nay nay never again a wise one said. With a carb intake 5 mins to remove and 5 to install. 

 

Just a thought!

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A machinest friend if mine swears by align honing the cam bearings for power and reliability. Cannot speak for it myself but his knowledge and experience has always been right. Just pointing it out because this is something you will not find in a crate motor.

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5 hours ago, wd6681 said:

A machinest friend if mine swears by align honing the cam bearings for power and reliability. Cannot speak for it myself but his knowledge and experience has always been right. Just pointing it out because this is something you will not find in a crate motor.

 

Good points. When we were kicking around the idea of rebuilding the Lincoln motor, we had made the determination up front that if we weren't going to use a GM Crate motor that was truely brand new and not a re-man, then we would rebuild it ourselves. No way I'd trust a generic rebuilder for something we are going to whoop on like we do in Champcar. All for those same reasons - inferior machine work, inferior parts.

 

Much to our surprise, not only was a NOS Vortec long block still available, it was something stupid like 1100 and change (with our buddy's discount) from the local GM stealership! We could not do a full rebuild using "good" parts and a "good" machine shop for the price, so we got lucky on that one. Heck for anyone using a generic GM application, I don't know if those are still available or not, but it's a bargain. 

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We had a pretty steep learning curve with our SBC in our Corvette.  We went through 3 motors in 3 events. The first one was the original motor that came in the car from 86 (we had no idea of the condition of it just had faith).  That one spun a rod bearing on the #1 main, It was an oiling issue at Daytona.  On dismantle we found cracked block and head (hairline cracks but not worth risk).

The 2nd motor was a cheap crate motor (as stated above we would never do that again), you have no idea how it’s put together or what bearings, rings, etc.  This time we wanted to remove all weak links, so we added good oil pan, acusump, new injection PCM and ignition systems for a stand alone TPI and also a new radiator.  Result, broke a piston and spit parts through whole motor, and cracked block. 

The 3rd motor was a local rebuild from an unknown shop that took 6 months.  That one also broke a piston but held together a lot better than the first last one.     

 

Finally we went to an old trusted friend to the rebuild.  Now we have something…  we take good care of it with high quality oil ($10/quart), keep the revs low (no more than 5K, but with TPI motor runs out of steam there anyway).  

 

As proven from the posts above, the SBC can be run successfully but you do need to take care of it.  Good oil pan, good Oil, and keep RPM reasonable.  

 

 

 

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On 8/20/2019 at 8:33 PM, cagedruss said:

Are you running an 88-92 Camaro?

 

I dumped the tune port intake just to make life easier. Removing the intake quickly is a hassle to do a repair. We broke a rocker arm and a lifter came out and had to pull the intake during the race. Nay nay never again a wise one said. With a carb intake 5 mins to remove and 5 to install. 

 

Just a thought!

we retained the factory 4bbl intake and carb from the 84. It will spin over 6 w/o much issue. the TPI tops out at about 5. The OEM 4bl intake is aluminum and it cleans up real easy. 

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  • Technical Advisory Committee
3 hours ago, mender said:

Back in the day on the oval I ran Pennzoil 25W-50 GT Racing oil in a well-baffled pan. 

Aren't oil viscosity requirements determined by the main and rod bearing clearances for a given engine?

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16 hours ago, wd6681 said:

What weight oil do most of you guys run in your smallblocks for endurance racing?

 

 

I use about 7-8 qts and I usually use 5 of the Amsoil Dominator 15-50 and then cut the rest with Amsoil 10-40.

 

For everything else (trans & rear) I use the heaviest of whatever recommended selection is possible. Heat is thy enemy, higher weight is thy savior for breakdown. 

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45 minutes ago, pintodave said:

 

I use about 7-8 qts and I usually use 5 of the Amsoil Dominator 15-50 and then cut the rest with Amsoil 10-40.

 

For everything else (trans & rear) I use the heaviest of whatever recommended selection is possible. Heat is thy enemy, higher weight is thy savior for breakdown. 

How often you change engine oil?

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1 hour ago, Team Infiniti said:

How often you change engine oil?

 

I get itchy if I let it go more than "a race". In reality it could probably go longer. For example, the Dec race, we only ran about 7 hours so I will not change it before this Sebring. Wait - I did have a test day though... I dunno, I might change it LOL. I ordered Blackstone Lab sample kit, never sent it off 🤣

 

Tranny is more of a toss up. I am to the point of letting it go a couple of events, unless I know it was getting nuclear hot like Charlotte a couple years ago when the exhaust was touching it. 

 

Rear end, I've worked up my confidence to 30-40 hours. That Amsoil Severe Gear 140 or whatever weight it is is ridiculous. It always dumps out darn near clear & clean. Nothing scientific about my visual test, a Blackstone analysis would be more appropriate... 

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