neagan

iTrader: (7)

My 1988 IROC 350 is in the shop getting an adjustable fuel pressure regulator,plenum cleaned,9th injector bypassed, inline pressure guage installed, ect. It was blowing lots of fuel fumes out the exhaust prior.

The mechanic told me that now these items are taken care of, I'm still getting smoke and it's oil. I mentioned the valve guide seals, and he said that he thinks in this year L98 it's the valve guides instead. Does that make sense? I know nothing about Heads (other than what my girlfriend has taught me). Are there engines without valve guide seals? Are some year GM V-8's prone to having the guides wear instead???

I could really use some education here. Thanks, NITRO

Apeiron

Valve stem seals are easy and cheap to replace. Valve guides are most decidedly not. It sounds like your mechanic could be trying to make some money.

sqzbox

I would say it's both. When the seals wear out they leave more oil on the valve stem which goes straight to the valve guide. The valve guide operates on strict tolerances and when they wear more oil will get sucked past the valve stem every time the intake valve opens. Permanent fix; Valve job Temporary fix; change to synthetic oil like Mobile-1. It has a high flash point that doesn't burn and smoke as bad as Arab oil !!

Dialed_In

iTrader: (3)

When does it smoke? If it smokes only on startup then it's the valve seals. If it smokes on decelleration then it's the guides.

midniteplowboyy

iTrader: (1)

What weight oil are you running? Have you changed the oil since the fuel problem? How many miles on the engine?

neagan

iTrader: (7)

Good Questions. Now that I've just taken care of the leaking Cold Start Injector, I can easily tell that it is smoke at start up. If I shut it off and go back out in a few minutes to restart, it blows a cloud of smoke again. The smoke clears up within a few seconds.

When I got the car in January, the guy got raving drunk as the deal progressed and I was not able to determine what type of oil he used. I put in Redline 5-30wt. The car has 146k miles, although they are fairly gentle miles (he was older and not a hot rodder- original owner). It sure ran significantly better with the oil change. The smoke issue didn't really happen when I purchased it, but progressed as my 9th injector continued to fail, so I thought they were directly related. Nitro

irocalot

Honestly, even at $2 a quart, it'll be cheaper to just keep an eye on the level and add as necessary with what you're describing. You don't need fancy oil in an engine that old, if it was properly maintained it'll go 200k, if not the damage is already done, and synthetic isn't going to repair worn bearings...

Stem seals are the biggest culprit for start-up smoke, but at 150k, the guides are probably also worn pretty badly as well, and I wouldn't waste any money on a "partial" repair.

Great flowing aftermarket heads are about $1k, and even a minor valve job on old heads is going to cost $250-$300 at the machine shop, plus labor to R&R them + gaskets and incidentals. Stem seals might be $10 for the seals + $200-$300 labor, but they aren't likely to completely fix the problem.

You could install stem seals yourself, but you'll need tools that almost equal the labor to have the work done, and most of a weekend in labor if you've never done it before ....or........

Buy some tint for the back window (so you don't have to look at the smoke)and a case of oil for the summer & start saving for a fresh motor...

neagan

iTrader: (7)

The engine sure runs quiet with no noise or vibration. With all my imports I'm used to owning, if there was a worn bearing, I'd drop the oil pan and replace the rod bearings that way- Much easier and by far cheaper.

However, it makes sense that I would save the band-aid money from the valve seals and put it towards a set of high flowing, high revving heads. I guess that's one more thing I'll have to research!

I've been trying to replace the brakes for four months, but there's allways something else demanding to be fixed. Can any of you point me to a worthwhile SEARCH thread for an Autocross oriented set of heads???

I'll get the gas masks and the rear window tint next week!
Thanks, NITRO

sofakingdom

iTrader: (1)

Heads = $1000-2000

Valve guide seals + valve cover gaskets = $25

I don't think there's much point in NOT replacing the seals. The savings aren't going to make much difference in getting you closer to a set of replacement heads. Might as well put an end to enjoying the mosquito-fogger effect.