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Discussion Starter · #1 ·
I use the V6 engine series 2 in a marine racing application and am suffering from high oil temperature, it has peaked at 345 F and as a consequence we have had a fair bit of bearing damage and re builds. My question is, has anyone any information or advice regarding the passage of oil through the engine that might cause this problem. We have an external oil cooler that I can touch the oil return line to the engine. Oil pressure is around 80 PSI. This is seriously modified engine, stroked to 4.2 L, custom rods and pistons, intense stage 3 heads, thrasher cam, vortech supercharger 21 psi, mondao intercooler, 1000cc injectors.
any information would be greatly received, and my first ever post...
 

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Discussion Starter · #4 ·
thanks for the info, we will go through it all and see what relates to our engine. Each time we take the engine apart the bearings are perfect, even with a little running with zero oil pressure, but the oil is always burnt, we have been using mobil 1 racing 4t 15w-50 which is now sold as a motorcycle oil
 

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Howdy all,


I hope I can help a little here. I have to wonder if tight bearing clearances are a contributing factor here, or perhaps oil thickness. For example:
stock engines use 5w30 oil and have approx. .0005 to .0015 rod bearing clearance, and .001 to .002 main clearance.Using a thicker oil here will increase presssure, but will decrease flow. Flow is the key to cool bearings.
In our race engines we run almost .003" clearance on main and rod bearings
in addition to using 10w30 oil. we have yet to have a failure. One of our engines ran at the Bonneville salt flats several passes of several miles at over 7000 r.p.m. and was then put into a drag car and made approx 100 passes in the mid to low 11 second area without bearing failure.
With this setup, I would be confident that you would be seeing lower oil temps unless yous cooler has an issue. Hope this helps.

BIG JEFF
 

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Discussion Starter · #6 ·
Hello Jeff, thanks for the reply, we run .0035 clearance on the mains and .00275 on the rods and based on your oil suggestion we will try a redline or purple oil at 10w30 and see what happens. The cooler is working as we can hold the return line to the engine for a while. :)
 

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jetboat said:
thanks for the info, we will go through it all and see what relates to our engine. Each time we take the engine apart the bearings are perfect, even with a little running with zero oil pressure, but the oil is always burnt, we have been using mobil 1 racing 4t 15w-50 which is now sold as a motorcycle oil
Alot of guys on the west coast of OZ are finding that Castrol synthetic 10-60w R is working very well for the turbo modified L67's. They reported a soot and burning problem with the mobil 1. Also the redline get a very high thumbs up by everyone who says they use it.
 

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Discussion Starter · #8 ·
OZ38 said:
Alot of guys on the west coast of OZ are finding that Castrol synthetic 10-60w R is working very well for the turbo modified L67's. They reported a soot and burning problem with the mobil 1. Also the redline get a very high thumbs up by everyone who says they use it.
We are going to try a 30 weight Redline oil for our next race 20th November as well as enlarging the sump by a couple of litres in volume and add a temp sensor to the sump as well. Will post results after race.
 

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jetboat said:
One other question what sort of power are the turbo modified L67s making?
Its varied of course by the different turbos being fitted but one well known West Ozzie punter has dynoed his turboed L67 at 440rwhp.

I think they wound the boost up around 30psi for a short burst while they were tuning.
It's running a Garrett GT35/40R with FMIC, 1.9:1 ratio rockers and a larger fuel parts etc.

Visit the site who own the car, it's a Test Mule for their business.
www.v6supercharged.com.au

or the street commodore forum ( street talk ) and look for the sponsers section with F.I.T. ( Forced Induction Technologies )
www.streetcommodores.com.au

Cheers
 

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Discussion Starter · #11 ·
results of last race, 4 destroyed pistons,,but oil temp stayed low and oil pressure around 60 PSI. It was interesting to see the sump temperature was 140F a little to low and the temp after the oil pump showed 210F on its a way to the oil cooler. Definately sticking to the Redline oil and a 30 weight.
 
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