oil leaking from intake valve seat, Serious?

tbitz · 08:32 PM

I just removed the CIS system and intake runners on my 78SC in preperation for my CIS-to-EFI project (by the way this can be done with the engine in the car, no partial drop needed). It is winter here and the car has been sitting for a while now.

After the runners were removed I looked at all the intake valves and saw oil on top of the intake valve #1. The valve also had carbon deposits around it. The only place oil can get there is from the valve guide, correct?

Is this serious? Here is a pic:

RoninLB · 02-21-2003, 08:30 PM

Quote:

Originally posted by tbitz
I The only place oil can get there is from the valve seat, correct?

Is this serious? Here is a pic:

you do mean valve guide, right

tbitz · 02-21-2003, 08:33 PM

Correct, guide is what I meant to say (12:20am and I'm tired...

.
I've edited my post.

RoninLB · 02-21-2003, 08:42 PM

OK.. well if that's the intake.. then the exhaust must be worse.. if it's the only valve to show the oil and you measured the valve to valve guide play to be OK.. then I suspect a valve guide seal.. a replacement job is no big deal.. and cheap/maybe $.50

RoninLB · 02-21-2003, 08:46 PM

woops.. you only eyeballed the intake valves... so you don't know about the exhaust valves.. so a check of all exhaust valves to exhaust valve guides is what I would do next...

tbitz · 02-21-2003, 08:53 PM

I went back and looked at the other intake valves again. They all show signs of carbon deposit on them, but only #1 actually has oil on top.

How can I measure the valve, to valve guide play? Can this be done with the engine in the car?

Looks like I need Waynes engine rebuild book, ASAP....

RoninLB · 02-21-2003, 09:16 PM

Quote:

Originally posted by tbitz

How can I measure the valve, to valve guide play? Can this be done with the engine in the car?

the routine is to have the valve off its seat and use a screwdriver as a lever to move it around/engine in the car.. I never had to do it.. so I can't say what's allowable, if any play is allowable at all.. but if I had an exhaust valve w/ a few thousandths of play I'd do a valve job.. you gotta check with someone who would know what you can get away with.. I figure your not loading spark plugs w/oil or you would have said it.. anyway, exhaust valve play is a serious concern

tbitz · 02-22-2003, 07:47 AM

I removed the spark plugs this morning. Here is the evidence

Spark plug #1:

Spark plug #2:

Spark plug #3:

Spark plug #4:

Spark plug #5:

Spark plug #6:

RoninLB · 02-22-2003, 07:52 AM

cocky poo.. probably a valve job in waiting.. I'd start w/ the valve guide test.. how many miles on this engine anyway?

yelcab1 · 02-22-2003, 08:03 AM

if you are this deep into it, I would do a valve job too. Then, when the EFI is done, you have a perfect engine with it.

Then again, that is just me.

RoninLB · 02-22-2003, 08:34 AM

Quote:

Originally posted by yelcab1
if you are this deep into it, I would do a valve job too. Then, when the EFI is done, you have a perfect engine with it.

Yep, me to..

but for S&G the max valve play in the '77 Tech Spec book is intake .15mm/.0059in, and exhaust .20mm/.0078in.. max means they are shot/kaput

APKhaos · 08:48 AM

Be prepared to find that carbon build up is more widespread than just the valves & heads. You valve job might need to include some heavy duty piston cleaning, new rings, and it makes sense to do the rod bearings while you are in there.

This might give you an idea of what to expect........

john walker's workshop · 02-22-2003, 08:45 AM

could be as little as a stem seal that came loose from the guide. they act as a nice little oil pump as they ride along with the valve stem. intake guides wear at a slower rate than exhaust guides. often at valve grind time, the intake guides are still in decent shape.

RoninLB · 02-22-2003, 08:50 AM

Quote:

Originally posted by APKhaos
Be prepared to find that carbon build up is more widespread

maybe we can keep the benefit of the doubt before his brain goes kaput.. I hope it's only guide seals.. gotta test the play in those valves.. and I don't like the factory specs for max play.. seems to much, IMO...................Ron

tbitz · 02-22-2003, 08:56 AM

Thanks for the input guys.

If replacing the valve stem seal can be done with the engine in the car, this is what I'll do. Then drive for a while a check the plug again. To see if it fixed the problem.

The question is can the seal be replaced with the engine in the car? I would use the Teflon seals instead of the Viton as recommened by many...

Odometer shows 115,000 Km (but I cannot be sure this is true).

RoninLB · 02-22-2003, 08:59 AM

Quote:

Originally posted by tbitz
[B
The question is can the seal be replaced with the engine in the car? [/B]

I think the question is what is the valve play

tbitz · 02-22-2003, 09:23 AM

With intake valve #1 fully opened I tried to move it side-to-side using a screw driver. No movement at all. Just to compare, I also tried #6, same thing, no movement at all.

I think it's time to open the valve covers. I'm guessing the valve guide seal can be replaced from there?

john walker's workshop · 02-22-2003, 09:58 AM

often on early SCs, the valve spring breaks, mostly on intakes. worst case, both the inner and outer springs go, and they can chew up the spring seat, the stem seal and the top of the guide, to the point where there's nothing left to attach the seal to. pelican probably sells the tool to remove the spring with the engine in the car. just have a good look down there with a mirror when it's out.

Doug Zielke · 02-22-2003, 10:17 AM

Interesting coincidence, JW .......
I saw some SC cylinder heads in the state (chewed up) you described, at the shop that recently did my heads.

tbitz · 02-22-2003, 12:36 PM

I removed the valve cover. I looked inside with a mirror. I could not see any broken springs or anything, mind you it is difficult to see in there. It looks like the rocker has come out before you can get to the springs and valve guide seal.

I'll probably leave this job for the summer and try and finish up my CIS-to-EFI now.