Road Race Engine and Oil Restrictors
 

I have an SCCA ITE Road Race car that I have raced for a few years. It has a 383 with Ai heads that has a solid roller in it.

Recently, I have an issue with oil pressure in my car. At the end of long straights it seems to lose pressure slowly towards the end. It will run 65 lbs. all over the place and at the end of the long straights it will slowly drop to about 45 lbs. It does not move in any turn due to sloshing. The problem has persisted across two blocks and oil pumps. (A motor failure last year) Oil pump is a Melling MV 10555 HV pump. The oil pan is a Canton Road Race pan.

I put in a Accusump over the winter in hopes of correcting this issue. It seems to have had no effect. The engine builder set the pickup height at 3/8". He is recommending oil restrictors drilled out to between .070 and .090 to help keep excess oil off the top of the motor. As usual, upon doing a search for something such as this, I get folks who recommend them and those that swear the sky will fall if I DO use them! Problem is the only folks using them are drag racers, and the folks who cry foul are street guys......

I have a solid roller set up with Xldyne components.....which given the cost of, I don't want to mess it up!

Anybody have any experiences with them? I would love to cure my little "bug" in the car.....

Thanks!

What are the oil temps doing when you go down the straights. Is the block filled at all and do you have an oil cooler?

What are you using to monitor oil pressure a mechanical gauge or an electric sending unit. If you really wan to see that its doing use a mechanical gauge with a 1/4" line run to it. Thats what i usually do on the racier engines I deal with, it'll show you quick if pressure falls off.

Tell us more about the oil pan setup, is there a scraper or windage tray or something to stop the oil from climbing the back of the pan? Whats the capacity of the pan and what are you running in it. Slosh left and right is alot different than under dive and acceleration. It could also be that the oil is foaming up. What kind are you running? You are also running quite a bit higher rpm for sustained time on the straights vs other places.

Fwiw I have not run oil restrictors in anything besides a big block olds.

Oil temps are in the high 200's.

The block is not filled.

I have an oil cooler in a new AFCO Racing radiator. Capacity is like 11 quarts with all the lines and such.

The guage is a mechanical Autometer Sport Comp with -4 line to the fitting above the stock oil filter.

The oil pan is the standard Canton Road Race pan with trap doors all around the pick up. No windage or scraper on the back of the pan. It has a baffle though....lemme see if the website has a pic of it.

I am running Redline 40 wt. race oil

Yes, I am running it right up to the 7,000 PCM limit most of the time....car screams down the straights.

Any other input would be helpful....

If you did put in oil restrictors do you think drilling them to .100 is enough??

Thanks!:cool:

Best photo I could find is the model 15-242t on this page:

http://www.cantonracingproducts.com/...road_race.html

We put oil restrictors in all our solid roller road race motors, you don't want all that oil going up to the top end since the lifters are not using it. At refresh time the bearings and valvetrain parts look like new.

That is good to hear. The motor builder told me to just look for bluing on the push rods to indicate too much heat/not enough oil.

Do you drill out the restrictors? If so to what size?

Thanks!

Could be a good idea,but I like the oil up top to help cool the valve springs. Especially since your at WOT a lot.

I've used them and recommend them. Drill them out to .090" and all will be good.
In drag engines, I usually tap the lifter feed holes in the rear cam bearing oil groove, and install a pair of set screws drilled out to .035". Your road racer will need a bit more oil to the rockers and(as mentioned) cool the springs, than an 8 or 9 second drag car.

Good Luck