What oil to use GM 3.4L for a ChumpCar?

[09_GXP]

Alright so I have rebuilt a 3.4L pushrod motor out of a 1995 Firebird for use in my Fiero that is running the ChumpCar series. For those not familiar it is for "$500" cars and runs endurance races ranging from 7 hours to 25+ hours.

The motor is spec'd for 5W30. During the rebuild the average bearing clearance was 0.04 (Spec is 0.03-0.08). Currently the motor has 300 miles on it with Defy 5w30 for break-in. Oil pressure is around 55-60 PSI at 2000 RPM (Spec is 30-55).

I originally thought about going with Rotella T6 5w40 but with the clearances on the tight side and oil pressure on the high side I'm not sure if I want to go any thicker. Thoughts?

 

[440Magnum]

I'd go with a racing 5w30, personally. Pick your brand- Redline, Royal Purple, Joe Gibbs, etc.

 

[pbm]

They have Rotella 10w30 in gallon jugs at Walmart for $12.XX.
The 3.1 and 3.4 are known to run well on just about any oil (as long as the I-M gaskets aren't leaking).
I'd probably run a good 10w30 synthetic like M1, PP, QSUD, etc...

 

[dave1251]

Since you like to use M-1 judging from your signature. M-1 5W30 it should be easy for you to pick up.

 

[Nickdfresh]

VR1 10W-30...

 

[SEMI_287]

The older Gen 1 motors don't have roller lifters I'd use Defy or some Rotella T5 10w30 in it.

 

[A_Harman]

Since it's a 1995 engine, it should have roller lifters, so it doesn't need a high-zddp oil such as VR1. As long as the engine is pretty much stock, and running in a normal rpm range, good 5w30 synthetics will be OK. 10w30 would give a little more insurance against shear-related viscosity loss. M1 10w30 High Mileage is a very good oil that has 1000ppm of Phosphorous and slightly higher HTHS than regular M1. As long as you keep the oil temp below 300F, and can maintain at least 40 psi oil pressure, you should be OK.

 

[09_GXP]

It does not have roller lifters, other engines had converted but not this platform. Unfortunately I will not have oil temp in place for our first race next weekend. Sounds like equal votes so far for a syn PCMO and Rotella 10w30. I want the higher ZDDP so am leaning towards the Rotella 10w30 if it will hold up to the heat.

 

[4x4chevydude]

SOunds like something that RP would be good for a high perfarmance oil like that would certainly stand up to the test...IVe seen it in 15w40 if you were thinking thicker..

 

[dave1251]

Originally Posted By: 09_GXP
It does not have roller lifters, other engines had converted but not this platform. Unfortunately I will not have oil temp in place for our first race next weekend. Sounds like equal votes so far for a syn PCMO and Rotella 10w30. I want the higher ZDDP so am leaning towards the Rotella 10w30 if it will hold up to the heat.


I personally do not buy into just the lack of ZDDP is a cause of failure. SAE studies has shown that 500PPM and above is more than sufficient to prevent wear and more is not better along with blenders are using more expensive anti-wear agents other than ZDDP. IMO failed cams and blaming modern oils was more often than not a cop out.

ftp://ftp.astmtmc.cmu.edu/docs/gas/seque...%2002-24-04.pdf

 

[A_Harman]

Originally Posted By: 09_GXP
It does not have roller lifters, other engines had converted but not this platform. Unfortunately I will not have oil temp in place for our first race next weekend. Sounds like equal votes so far for a syn PCMO and Rotella 10w30. I want the higher ZDDP so am leaning towards the Rotella 10w30 if it will hold up to the heat.


Does the car have an oil cooler on it? If not, I'm thinking that you need a very oxidation-resistant oil. Valvoline NSL 10w30 would stand up to the heat better than VR1 conventional. Don't know if you can find it. My local NAPA has it. NSL stands for Not Street Legal, so it is a dedicated racing oil, and will not go for extended drain intervals. But the Phosphorous is nice at 1200 ppm, and the Flash Point is a very nice 248 C.

If you really want Rotella, make it T5, which is semi-synthetic, not Rotella T, which is conventional.

I'd stay away from RP.

I still think that M1 10w30 HM would be good for this application.

 

[09_GXP]

The car does not currently have an oil cooler on it. I'm not too worried about extended drains, it will be getting a change after each race.

However, I did find some gallons of SL Royal Purple for $20 at Meijer this evening so I think that may be the direction that I will be heading.

 

[lilred67]

we ran straight 30 in a Mazda during a 24 hr. Chump Car Race @ Texas Motor Speedway in June 2010. Wasn't concerned about a multi-vis oil with the abient temps. being 90f + during the entire race. we finished 11th out of 40+ that started. we run Mobil 1 10-30 in a ford probe. oil selection has not been the problem with the ford, over heating issues have.