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smoking problem found.... maybe

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the seals on the intake valves seem ok but there are none on the exhaust valves. So if the guides are to lose the oil will just run down the valves and blow out of the exhaust. Maybe i have a combination of bad guides and to much oil pressure?
 
obrut said:
the seals on the intake valves seem ok but there are none on the exhaust valves. So if the guides are to lose the oil will just run down the valves and blow out of the exhaust. Maybe i have a combination of bad guides and to much oil pressure?
Click to expand...

I would say yes.
I started a poll about a year ago on this EXACT same issue to determine if there was any correlation between the HVP and smoke. No one replied to it.

I run the HVP and my guides are not the best shape. There is a bit of smoke at during start-up, but no smoke after that. The best fix for this is to open the oil drain holes (you can see the Head gasket material blockage) and that should resolve most of this. I DID in fact FORGET to drill mine out :mad:

You can also reduce some of the oiling on the top by drilling the center oil feed to the crank.

FWIW;
Exhaust valves (as you know) do not have seals. Some have had good luck, but I would advice against installing them. Same with bronze guides - They do not last. Cast iron guides are proven and have a similar expansion rate as the stem.

Edit:
If the root cause of smoke is oil through the exhaust guide, the issue is not pressure, but flow. Supply vs return flow.
 
Its unlikely for the engine to smoke while its running because of a bad exhaust guide. It may puff smoke on a start up after sitting for a while or overnight due to a worn guide. However while its running there is pressure in the exh port which would tend to push the oil away from the combustion chamber, unlike the intake guide which has a vacuum pulling on it.
 
lazaris said:
Its unlikely for the engine to smoke while its running because of a bad exhaust guide. It may puff smoke on a start up after sitting for a while or overnight due to a worn guide. However while its running there is pressure in the exh port which would tend to push the oil away from the combustion chamber, unlike the intake guide which has a vacuum pulling on it.
Click to expand...
Exactly! :biggrin:
 
lazaris said:
Its unlikely for the engine to smoke while its running because of a bad exhaust guide. It may puff smoke on a start up after sitting for a while or overnight due to a worn guide. However while its running there is pressure in the exh port which would tend to push the oil away from the combustion chamber, unlike the intake guide which has a vacuum pulling on it.
Click to expand...
Sure: BUT- the stem passes through the exhaust runner on it's way into the chamber. It doesn't take much sneaking into the runner to make a bunch of smoke. It wouldn't show up on the plugs either. The flow in the runner would draw the oil, just like flow in the throat of a carb pulling gasoline from a jet.
 
the spark plugs were always clean. The gauge i brought home from work wont fit. But i have a friend that has one that i can use. So tomorrow or wednesday i will have some measurements and we will see how bad they are. From what i can see now, it is way more than .002 I will get some pics with the valve out and you will be able to see how bad the oil is leaking down the guide. Next i will have to find a good machine shop in the chicago land area. I tried to call ANS but the number has been disconected. Any suggestions?

Tim
 
i called a machine shop that was recommended by a few members and it looks like i have a few options.

1 I can have the guides sleeved with bronze and then a valve job

2 They can sleeve the guides and cut the exhaust guide to except seals which would mean changing to new exhaust valves.

3 Replace the guides with new ones and then a valve job.

Anyone have any input on sleeved guides? Should i have the guides cut to except seals?

I was just going to have the guides changed and then just have the rest of the head done.
 
Jerryl said:
FWIW;
Exhaust valves (as you know) do not have seals. Some have had good luck, but I would advice against installing them. Same with bronze guides - They do not last. Cast iron guides are proven and have a similar expansion rate as the stem. ............
Click to expand...
IMHO ........ Since the engineers at GM did not see the need for them (as stated in previous threads), and there are many engines out there that do not smoke without the seals installed. This was the main reason I did not install exhaust stem seals on my heads. The seals will get rid of the smoke in this area, but, there is no data how long the guides / valves last with them.
 
Do NOT sleeve the guides. Have them install brand new IRON guides...to hell with bronze....JUNK!!!!Racing hype no good for street engines.
To check your guide clearance, buy a "gauge pin" from McMaster.com, sized exactly to what the size should be. Buy one a couple thousandths oversized as well. Slip it into the guides and tell us how they fit. This is a cheap way to check...no need for bore gauges. Mcmaster delivers next day.
Totally sounds like guides. I cant tell you how many "machinists" down know how to do heads right. There are so many things that can kill a set of heads.
 
I've got some gauges that will work. So i'm going to pull all the valves and measure everything hopefully tonight. I really wanted to just have new guides installed, new seals on the intake valves, and a valve job. I will post the measurements tonight if i get time to take them apart.

Tim
 
i checked one head last night. I only did the exhaust valves each guide measured out at .342 and it looks like the valves measured at .340 which means there fine. I'm going to check them again because i still think there is a problem.
 
obrut said:
i also wanted to add that i had the turbo rebuilt twice and installed the pvc catch can and still had a smoking problem. I will be pulling the heads this week, can anyone recommed a good machine shop in IL?
Click to expand...

This is interesting, as I'm in the same boat. Previous owner chased a turbo and I chased PVC, and I'm still smoking a bit on start up and idle as you say. I'm going to try chasing intake gasket first and if that doesn't work off come the heads......

I'm in IL too, have a good machine shop in the southern part of the state. Very reasonable prices compared to Chicago, top quality and worth the drive.

sg333e@yahoo.com
 
ya i did the same thing, two turbos, two intake gaskets and i tried the pvc catch can. I really think this is my problem, it obvious that oil is running down the guide and that would explain the smoke on start up.
 
I'm off to the machine shop tomorrow. I think i'm going to have the guides cut for exhaust seals. Are there any types of seals i should stay away from? Is there anything else i should consider before having this done?

Tim
 
obrut said:
ya i did the same thing, two turbos, two intake gaskets and i tried the pvc catch can. I really think this is my problem, it obvious that oil is running down the guide and that would explain the smoke on start up.
Click to expand...

I think your on the right track.;)
I got a place here in Mokena just for future reference. Romuto Racing. they have done a few tb motors in the area. ANS is shut down. Where are you located in Il.?

Rick
 
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