Quoting cheekychimp:
I'm confused here. Surely if this is true, all the 4G61T engines would be seeing insane oil pressures in stock form if they have no balance shafts. I'm beginning to think there must be a solution here.
Paul.
Quoting Alpha Male:
Yeah, porting the relief valve..
But aside from that, maybe they have some part of the engine that is slightly different to relieve pressure .
Either way, I've ported the relief valve and had great results.
Yeah but Josh that's just it. Porting the relief valve is a band aid and it's solving a symptom not the cause. If you guys don't want to discuss it,I understand. It isn't that you aren't trying to help and yes I know sometimes (alright a lot of the time) I DO over complicate things, but I think this is a pretty big issue that everyone really seems unconcerned with.
Quite a few years ago, people decided that it was a good idea to drop the balance shafts because you got 10 extra horsepower, it was one less belt and failure to worry about and they really didn't do much anyway. It raised oil pressures a bit but hey what the hell. You guys all know what oil pressures of 140 psi can do to an engine. Magnus has pages of tech articles on their site talking about oil supply issues relating to crankwalk and yet everyone breezes over this issue as if it is unimportant.
Porting the relief hole does work yes, but people have also documented that even after porting out the hole they have further reduced oil pressures by either cutting coils of the relief port plunger spring or backing out the retaining bolt using crush washers. This suggests to me that the plunger isn't depressing enough and even if you port the hole you aren't getting the full benefit because the plunger isn't going far enough to take full benefit of it.
And where are we measuring oil pressures? If we are taking a reading off the oil filter housing does it come prior to or after that oil relief port? If it is before the restriction, it is hardly surprising oil pressure is high and doesn't necessarily indicate what pressure is in the block and at the head.
I know nothing about 4g61s but I am damn sure they are not running around ten a penny with 140 psi oil pressures from the factory just because they aren't using balance shafts. Is no-one interested in why that is? I realize it is over complicating things if 10 minutes with a dremel "solves" the issue, but a lot of good mods evolved from people taking some time to think things through. I know you understand that Josh or you wouldn't be fussing around with EVO VIII axles when people have run 11s or faster on 1G and 2G stuff.