I'm posting this here since this is my first post and I don't really know much about the 4G61 platform, so I am hoping that I am not making a fool of myself.

I come from a 4G63 background and I have recently become very interested in the issue of increased oil pressures seen in the 4G63 engines following a rebuild. Now I know it is well established that in almost every case that this phenomenon occurs, the culprit is the removal of the 4G63 balance shafts which accounts for a sharp increase in oil pressure. Now people have had varying amounts of success in addressing this issue by porting the oil filter housing pressure relief valve and using Kiggly's HLA pessure relief distribution block at the head.

What I am here for however is to ask you guys specifically about the 4G61 block. When we remove the balance shafts from the 4G63 we use a balance shaft eliminator kit which is essentially just an oil pump shaft for a 90 Mirage without the rear shaft attached. So, if the oil pumps on the 4G63 and 4G61 are the same (as I've been told!) then since your engines came stock without balance shafts, you should all be seeing the same insane oil pressures that we see when we remove the balance shafts. I just find it hard to believe your engines came stock from the factory like that.

If any of you have logged oil pressures, I'd be interested to know what pressure you guys see at: -

Cranking on a cold start
Idle
Cruise
WOT

If as I suspect you are not seeing 100+ psi on a cold start and 140+ psi at WOT could anyone who knows these engines suggest how the 4G61 block regulates oil pressure without balance shafts?