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Some months ago I did the post on my friends SBC that has RHS vortec heads, 880 Vortec block, hydraulic roller cam, etc. The issue is ever since we`ve installed the Vortec heads it has a smoking problem. At idle smoke just boils out. The funny thing is it doesn`t smell like oil, but it`s not coolant, it`s not tranny fluid, it`s oil confirmed. He drives it daily to work and it uses about a half a quart a week, his work is a 40 mile round trip per day. Today we pulled the head studs on the intake valves to make sure they had sealant on them as the stud boss goes into the intake runner. This didn`t help matters any. The machinist told me he didn`t put valve stem seals on the exhaust valves and I`ve found real conflicting answers on it. Some say since there is no vacuum on the exhaust port it won`t pull oil in, others say this is why it smokes because the exhaust port creates a venturi effect when exhaust gas passes through it. I also pulled a few plugs today and they were very clean, the mixture is close to spot on.
I didn`t pull all the plugs as we didn`t have time. My friend said we`ll try the remaining issues of what it maybe such as a leaking intake and we`ll install seals on the exhaust valves. If this doesn`t stop it he wants to pull it out next spring and find what the issue is and I have to agree with him. The car has outstanding power, starts quickly, and is a pleasure to drive. The smoking issue wasn`t happening with the old camel back heads we had on it, the smoking didn`t start until we installed the Vortec heads. The mysterious part to this is if we change the oil the smoking just about completely stops, it`ll smoke very little for about a week, as the oil breaks down and gets thinner the smoking returns. This is just a update on things. I`m really at a loss on what`s causing this. It has good compression and runs fine but the smoking has got to go.
 

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oil

I assume it’s smoking out of the exhaust?? Both sides, or is it a single exhaust application?

What intake??? Is it a Vortec style or a non-Vortec that was made to fit???

There are some design heads where the placement of the drain back holes are way to high on the head. This allows the top of the guides to swim in oil. I have never had a set of the RHS Vortec’s in my shop so I do-not know if this could be an issue, but you should look at it. Added to it, if thee machine shop cut the guides down for greater clearance it can make the problem worse. IMO anything that goes out my doors gets a positive seal on it. Unless it a stock build.

Sucked, Intake gaskets would also be top of the list to look for…

Keith
 

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Discussion Starter · #3 ·
Thanks Keith. It has a edelbrock performer Vortec intake. It has true dual exhaust with no X or H pipe and it smokes out of both sides. As far as I know when we got the heads they came with the guides clearenced for higher lifts. I checked the drainback and it`s working as it should. He and I already agreed we`d pull the intake next and install some valve seals. I gathered that if it were coming from the intake we`d see oil on the plugs and if it were the exhaust guides leaking there wouldn`t be any oil deposits on the plug.
The few plugs I took out all were really clean. Another odd thing is the smoke doesn`t come out of the exhaust quickly like it`s being pushed out, it just dribbles out slowly and lazily in thick blue clouds. It`s puzzling to me why the smoking stops for a while after we change the oil.
 

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DoubleVision said:
Some months ago I did the post on my friends SBC that has RHS vortec heads, 880 Vortec block, hydraulic roller cam, etc. The issue is ever since we`ve installed the Vortec heads it has a smoking problem. At idle smoke just boils out. The funny thing is it doesn`t smell like oil, but it`s not coolant, it`s not tranny fluid, it`s oil confirmed. He drives it daily to work and it uses about a half a quart a week, his work is a 40 mile round trip per day. Today we pulled the head studs on the intake valves to make sure they had sealant on them as the stud boss goes into the intake runner. This didn`t help matters any. The machinist told me he didn`t put valve stem seals on the exhaust valves and I`ve found real conflicting answers on it. Some say since there is no vacuum on the exhaust port it won`t pull oil in, others say this is why it smokes because the exhaust port creates a venturi effect when exhaust gas passes through it. I also pulled a few plugs today and they were very clean, the mixture is close to spot on.
I didn`t pull all the plugs as we didn`t have time. My friend said we`ll try the remaining issues of what it maybe such as a leaking intake and we`ll install seals on the exhaust valves. If this doesn`t stop it he wants to pull it out next spring and find what the issue is and I have to agree with him. The car has outstanding power, starts quickly, and is a pleasure to drive. The smoking issue wasn`t happening with the old camel back heads we had on it, the smoking didn`t start until we installed the Vortec heads. The mysterious part to this is if we change the oil the smoking just about completely stops, it`ll smoke very little for about a week, as the oil breaks down and gets thinner the smoking returns. This is just a update on things. I`m really at a loss on what`s causing this. It has good compression and runs fine but the smoking has got to go.
So much for the theory that exhausts don't need seals. But before we get there; chasing K-Star's thought of the oil level in the head being high enough to flood the tops of the guides is worth taking a look at. If the drain back stays under the tops of the guides, you could try the simple factory umbrella seal on the exhausts. This can be done without removing the heads which makes it fairly easy to do. Then you can take a look at if the oil consumption changed with little expense and effort. If the drain back oil is above the guide, then you need to either modify the drain holes to alliviate the problem or install positive guide seals. We're assuming the guides and stems have proper clearance here, obviously excessve clearance will pull oil no matter what type seal is used.

Another thing you could try is a colder range spark plugs. We're dropping the temp on the plugs to make it easier to to foul them, just to see if this is a combustion chamber problem, that would isolate whether the problem was on the intake gaskets, guides and or piston rings from whether it's a problem of oil getting down the exhaust guide. the thought being that oil being pulled into the chambers will at some point oil foul the plugs as they won't run hot enough to keep themselves clean. but if they stay clean or only fuel foul, then it's a fair bet that oil is getting down the exhaust side where very little if any oil would get into the combustion chamber from there.


Bogie
 

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Discussion Starter · #5 ·
The heads were purchased new from a online source and they were dirt cheap. I think the total was around $479 a little over $500 with shipping.
They were brand new in the box. The machinist said the guides checked out perfect. They were made of Quality cast iron and were real heavy castings.
I had a set of Manley street master 1.94 1.50 valves that had around 15,000 miles on them and I let him use them. We took the heads to my machinist and he set them up. We installed the heads and was really wondering why it was smoking so much. So I went back to see my machinist and asked him what valve seals did he use and he said "I installed seals on the intake valves but not the exhaust, the exhaust had ideal clearence and since it doesn`t pull a vacuum it doesn`t need a seal" When he told me that it went against what I had always been taught which was use them on intake and exhaust.
So since then, we`ve been chasing the gremlin. We checked the compression, 190 to 195psi on all cylinders. We checked the modulator valve to make sure it wasn`t pulling in tranny fluid. We checked the pcv with a clear hose so if any oil was being pulled in we`d see it. I checked every valve`s movement to make sure none were sticking open. We did a pressure check on the cooling system and it held pressure perfectly. 1BAD80 very generously said I could use his leak down tester but I turned him down as we live a 1000 miles away from each other and I didn`t want to take the chance of it getting broken in shipping. Next on the list is to install valve seals and if that don`t stop it, we pull the intake next. If it still smokes afterwards means it comes out next spring as I must have made a mistake when I did the build.
I`ve chased problems in the past before but never one like this one. You can stall it to around 2400, nail the throttle to the floor and let off the brake and the rear end will squat way down and the back tires will lite off, the car pulls so hard on launch it plants you in the seat. We love the power and how it runs, but he feels like I do, I can`t stand to ride in a smoking car. Thanks for the help Keith,, Thanks also to you Bogie. If I have any hair left after this one I`ll be lucky.
 

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oil

What puzzles me are the plugs. If it's smoking from the pipes that means the oil has to be entering the cylinders. If it is sucking oil from the valley, AKA intake gaskets. The oil will be entering the ports as a vapor. I believe that I would yank the carb and get a flex light and a mirror and see if you can look into the ports past the intake face.

On the oil drain back hole. Not sure if i explaned that well enough. It's not a issues with the drain back hole being open. The hole is placed to high in the head causing the oil level to be higher then the top of the guide even with a open hole. If thats the case and there is no seal on there, that can cause a problem.

Can you talk him into yanking a header so you can see the ports on the exhaust side...

Keith
 

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Discussion Starter · #7 ·
A update. Today I pulled more plugs and found they all look the same, They also showed high speed glazing so I got my nephew who works at a parts store to pick us up some plugs that are 2 steps colder. It was obvious the plugs were getting a little too hot. None of the plugs show any sign of oil burning. I have a theory that could be wrong but if oil is getting past the exhaust valve guides is the valve hot enough to burn the oil?
Another part of this mystery is how funny the smoke smells, it don`t smell like oil but it is. I was thinking if it`s getting cooked off the exhaust valves and not burned in the combustion chamber then it would smell different but that`s just a guess. This weekend we plan on replacing the header gaskets so I`ll have a chance to look in the exhaust ports with a real close eye as I want to find out if oil is getting in past the guides due to there not being a seal. We`ve kept a constant check on coolant and tranny fluids and neither is low, it uses a half quart a week on oil so we know it`s oil. It`s also funny how we can do a oil change and the smoking almost stops completely for a week. This has been one of the biggest challenges for me since I`ve been in hot rodding but I won`t give up until I find the answer. Thanks for the help guys.
 
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