I have a 1989 L98 G92 Iroc-Z with about 117,000 miles on it. I Just started getting heavy blue/ white smoke @ start up for about the first 4-5 min of running but then goes away. I suspect valve seals. My question is, while I am there to replace valve seals, I wanted to replace valve springs and possibly change rockers. I need recommendations... What size springs???, Replace rocker arms??? and if so with what??? 1.5, 1.52, 1.6 ??? Not trying to spend alot of money. Just get bang for buck. Car runs really good now other than smoke.
I have stock heads, 083's I think, a ported stock intake with stock exhaust manifolds with all A.I.R. "stuff" removed. I also have Magnaflow cat-back exhaust with dual Magnalow Cats. I have a Comp XR264HR or 08-501-8 cam installed.
Basic Operating RPM Range: 1,200-5,200
Intake Duration at 050 inch Lift: 212
Exhaust Duration at 050 inch Lift: 218
Duration at 050 inch Lift: 212 int./218 exh.
Advertised Intake Duration: 264
Advertised Exhaust Duration: 269
Advertised Duration: 264 int./269 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.495 in.
Valve Lift with Factory Rocker Arm Ratio: 0.488 int./0.495 exh.
Lobe Separation (degrees): 112
Any help or recommendations
would be helpful. amfornal
Re: Gonna replace valve seals... New springs and/or Rockers????
Replacing the seals provides you with the perfect excuse to throw a set of full 1.6 roller rockers in there IMO. looking at your ride,..... I'm guessing the original springs are just fine.
Re: Gonna replace valve seals... New springs and/or Rockers????
I've got the Proform tool that I've been lazy about selling. Used on my job a few months ago. I don't plan on doing it again in this life. This is THE tool to do this on the car. I PM'd you.
Re: Gonna replace valve seals... New springs and/or Rockers????
What do you need commented about? It's a valve stem seal replacement. You get seals and optionally new springs and you spend an afternoon getting it sorted.
You may want to check max lift on your guides, etc before installing 1.6 rockers. You are already pushing it for stock head lift numbers - in fact that may be why your stem seals are leaking - they got smashed by the spring retainers due to excessive lift from that cam.
It is generally accepted that stock L98 heads are only good for .480 lift without modification.
Re: Gonna replace valve seals... New springs and/or Rockers????
Quote:
Originally Posted by GeneralDisorder
What do you need commented about? It's a valve stem seal replacement. You get seals and optionally new springs and you spend an afternoon getting it sorted.
You may want to check max lift on your guides, etc before installing 1.6 rockers. You are already pushing it for stock head lift numbers - in fact that may be why your stem seals are leaking - they got smashed by the spring retainers due to excessive lift from that cam.
It is generally accepted that stock L98 heads are only good for .480 lift without modification.
GD
Wow, I am an idiot... my coment on no coments was posted on the wrong post..... sorry
Re: Gonna replace valve seals... New springs and/or Rockers????
Dude put headers on that thing! The stock exhaust manifolds effectively neutralize any engine mods, they're terrible. I picked up 4 mph in the 1.4 with Dyno Dons on a stock L98. If your not going to do headers I wouldn't even consider spending money on rockers, just do the seals and save the cash.
Re: Gonna replace valve seals... New springs and/or Rockers????
Quote:
Originally Posted by amfornal
I have a 1989 L98 G92 Iroc-Z with about 117,000 miles on it. I Just started getting heavy blue/ white smoke @ start up for about the first 4-5 min of running but then goes away. I suspect valve seals. My question is, while I am there to replace valve seals, I wanted to replace valve springs and possibly change rockers. I need recommendations... What size springs???, Replace rocker arms??? and if so with what??? 1.5, 1.52, 1.6 ??? Not trying to spend alot of money. Just get bang for buck. Car runs really good now other than smoke.
I have stock heads, 083's I think, a ported stock intake with stock exhaust manifolds with all A.I.R. "stuff" removed. I also have Magnaflow cat-back exhaust with dual Magnalow Cats. I have a Comp XR264HR or 08-501-8 cam installed.
Basic Operating RPM Range: 1,200-5,200
Intake Duration at 050 inch Lift: 212
Exhaust Duration at 050 inch Lift: 218
Duration at 050 inch Lift: 212 int./218 exh.
Advertised Intake Duration: 264
Advertised Exhaust Duration: 269
Advertised Duration: 264 int./269 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.488 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.495 in.
Valve Lift with Factory Rocker Arm Ratio: 0.488 int./0.495 exh.
Lobe Separation (degrees): 112
That cam lift is too much for stock heads without some modifications. The retainers probably beat up the seals and is why they are bad. The same thing will happen if you put new seals on. If you increase the rocker ratio for more lift the problem will just happen much quicker, and you might also break springs.
If you're going for high performance then you need to pull the heads and change a few things. Most people just buy a complete set of aftermarket heads and replace them.
If you're going for the cheapest fix and upgrade, then you can get some smaller retainers with more clearance and increased installed height, springs, your new seals, and whatever rockers you want. That is with leaving the heads on the engine.
One of the previous posters was right about the exhaust manifolds. To get good gains from a cam like that you really need headers to allow for scavenging. It will make a large difference on that engine.
