Indy Aluminum Block Oil Pressure Issues

A friend of mine emailed me asking me about an issue he's having with his motor. I don't have any experience with Indy Aluminum blocks I was wondering if anyone on here can give us some ideas what to look for.

Thanks

Indy aluminum RB block with 572-13 indy heads with Comp elite roller lifters, non bushed lifter bores pushrod oiling, titan oil pump, new build 1st starup 85 lbs. psi cold and as the engine warms up, the oil pressure gets lower and lower. The oil temperature at the start of the burnout box is 140 and water temperature is 115-120 degrees.
At the starting line oil psi is dropped to 45 psi and as it accelerates goes to 60-63 psi at 6500 rpm's and then steadily starts going lower and lower.

Right at the stripe oil pressure is 33-35 psi and going down the return road is 18-20 psi at 1500-1700 rpms.

I have never seen this issue before with the Mopar Performance iron block. Nothing has changed except MP Megablock had lifter bores bushed, all internals the same except the Indy block lifter bores are not bushed this go around.

Any ideas on what the problem is and what it's going to take to fix it.

I've talked to a couple of guys who had problems with oil pressure in an Indy aluminum block. The lifter bores were the problem in both cases that I know of.

I'd suggest calling the guys at Best Machine and see what they say. They build a lot of engines with that block so they probably have a good handle on the issues.

I bet they will tell him to bush the lifter bores to fix those leaks. Probably the issue.

We had an issue with a cam bearing walking out on our Indy block causing low oil pressure.

I have seen it several times. Does the motor have a vaccuum pump?
You or he can call the shop and I will help you out.
336 283-0800
Todd

Yeah, that would do it too!

The big problem with aluminum blocks is the thermal expansion. If the engine builders aren't used to building with aluminum blocks they might not select the correct clearances. When the block grows the clearances open up. In some cases the clearances can open up enough to cause problems.

Thanks guys, You gave him some direction.

If it's not the cam bearings look at the crank for possible cracks.

I put in restrictors feeding my lifter galleys. But I don't pushrod oil.

I had this problem about 10 years ago...We put restrictors feeding the lifter galleys and we do oil feed through the push rods

Oh some of us mentioned the oil drain holes but I did it over the phone 3 times yesterday.......Todd

opened up the drainback holes only to loose a broken lash cap down there. glued a strainer over the hole for safety now.