Looking for some Help...SBC Oil fouling plug

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Horder
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Looking for some Help...SBC Oil fouling plug

Post by Horder »

Looking for some help on my new engine with less than 500 miles. It developed a misfire and I discover #1 plug was oil fouling. I changed the plug and pulled it after a ride and noticed it’s got some oil on it again. I went with a 1 heat range hotter plu. I had Autolite 3924 in that the head manufacture suggested as a starting point.

Engine as follows

327(Chevy II block) .040” over with forged and balanced rotating assembly.
Just over 10:1 with flat tops, 60cc and .039” quench
Trick Flow double hump look a like heads. 260 cfm intake and 208 cfm exhaust at .550 lift
67 Z28 winters intake with a 600 Holley Double Pumper
Howard’s retro roller cam 275/278 adv, 223/226 @ .050”, .540” lift 110 LSA
Headers, 2 1/2 exhaust
Muncie, 12 Bolt, in a 66 Chevy ii

Some background

Trick Flow heads have rocker studs that enter the intake ports. I sealed bolts with Kleen Flo antiseize and sealing compound. Maybe a mistake???

I used Fel Pro intake gasket with print o seal

I had some oil seepage from the second from the front intake bolt on the drivers side closest to the #1 cylinder. I pulled it, cleaned and applied sealant and retorqued Nothing since

I have 160-170 compression

All other plugs look great with # 8 “possibly” having a touch of oil on it.

A few times after I have shut the engine off, I have heard a quiet, high pitched ringing noise that lasts for a few seconds. Unable to locate as of yet.

Was hoping to get some hints on where to start...

Pull rocker studs and reseal?
Pull and reseal intake?
Valve seals?
Rings?

Any help is appreciated...

Rob
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Re: Looking for some Help...SBC Oil fouling plug

Post by Walter R. Malik »

Horder wrote: Tue Aug 02, 2022 11:48 pm Looking for some help on my new engine with less than 500 miles. It developed a misfire and I discover #1 plug was oil fouling. I changed the plug and pulled it after a ride and noticed it’s got some oil on it again. I went with a 1 heat range hotter plu. I had Autolite 3924 in that the head manufacture suggested as a starting point.

Engine as follows

327(Chevy II block) .040” over with forged and balanced rotating assembly.
Just over 10:1 with flat tops, 60cc and .039” quench
Trick Flow double hump look a like heads. 260 cfm intake and 208 cfm exhaust at .550 lift
67 Z28 winters intake with a 600 Holley Double Pumper
Howard’s retro roller cam 275/278 adv, 223/226 @ .050”, .540” lift 110 LSA
Headers, 2 1/2 exhaust
Muncie, 12 Bolt, in a 66 Chevy ii

Some background

Trick Flow heads have rocker studs that enter the intake ports. I sealed bolts with Kleen Flo antiseize and sealing compound. Maybe a mistake???

I used Fel Pro intake gasket with print o seal

I had some oil seepage from the second from the front intake bolt on the drivers side closest to the #1 cylinder. I pulled it, cleaned and applied sealant and retorqued Nothing since

I have 160-170 compression

All other plugs look great with # 8 “possibly” having a touch of oil on it.

A few times after I have shut the engine off, I have heard a quiet, high pitched ringing noise that lasts for a few seconds. Unable to locate as of yet.

Was hoping to get some hints on where to start...

Pull rocker studs and reseal?
Pull and reseal intake?
Valve seals?
Rings?

Any help is appreciated...

Rob
Personally, I would remove the intake rocker studs and clean them very well ... then re-install them, sealing those threads into the head with "Right Stuff".
That may not be your issue however, I have seen that being the problem numerous times.
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Re: Looking for some Help...SBC Oil fouling plug

Post by Tom68 »

Are you running rocker cover breathers with no vent holes between the pushrods ?
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Re: Looking for some Help...SBC Oil fouling plug

Post by Tom68 »

Can't imagine enough oil getting past a rocker stud even if you fitted it dry.

What ring package ?

An upside down second ring ?

What's your breather system ?
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
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Re: Looking for some Help...SBC Oil fouling plug

Post by golden_commando »

A too loose valve on its guide can make this as it moves sideways an let oil past the valve seal, did you checked the head before the assembly? Even a new head could be off specs sometimes, I would double check the valve seal if the guide is ok. Did the head or block got milled for compression/quench if yes did you remove material from the intake side as well? the vaccum with this cam should be ok to run with power brakes, if it is low the problem could be the intake gasket side. If it is consuming a lot of oil could be an upside down ring as mentioned before or a broken ring, do the compression on all cylinder are within 25 psi?
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Re: Looking for some Help...SBC Oil fouling plug

Post by BillK »

Horder wrote: Tue Aug 02, 2022 11:48 pm
A few times after I have shut the engine off, I have heard a quiet, high pitched ringing noise that lasts for a few seconds. Unable to locate as of yet.

That sounds like a vacuum leak. What do you have as far as PCV / breathers setup ?
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Re: Looking for some Help...SBC Oil fouling plug

Post by dannobee »

Use a bore scope camera (or buy one from Home Depot) and after removing the carb, see if there's oil in the intake tract of #1. It could be the intake gasket or the intake itself, or a valve stem seal, or the aforementioned rocker stud. If you find nothing, look through the spark plug hole for anything obvious, although with good compression in all holes, it's likely something up top.

Rocker studs should be installed with teflon pipe sealant paste. The thick white GM stuff, PN 19333512/12346004 or equivalent.
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Re: Looking for some Help...SBC Oil fouling plug

Post by Horder »

Appreciate all of the responses!

here are the answers to the questions

The engine is built as a clone of a 66 L79 Nova. The Z28 intake looks similar to the L79 but flows better. Thats why it was used instead, the PCV system is the stock looking system as used on the L79. It was referred to as a closed system
The 1966 "closed" PCV system had a PCV valve that was threaded into the oil filler tube on the front of the intake manifold and a hose that ran to a vacuum port. Another hose went from the back port in the block and ran to the air cleaner. Hence the term "closed" because the breather was not open to the atmosphere. The air cleaner was the breather and any additional blow-by fumes that might escape were drawn into the carb or if the PCV valve became worn-out or clogged. Fresh air entered the back of the block and the blow-by was evacuated out of the front. The oil filler tube was sealed and did not have a breather on it. The PCV valve is not stuck and appears to be functioning. Valve covers are not vented and have no holes.

Ring pack is Mahle Plasma-Moly ductile 1/16. 1/16, 3/16.

Block had not been previously decked. Machinist/engine builder who built the short block took less than .012" off the decks. No material was removed from intake side. He installed the rings. Hes highly regarded in our city so I would bet its good but everyone does make mistakes.

Vacuum is 13-14 in/hg at 750-800 idle. Seems right to me for a small engine with a 275 adv cam on 110 LSA???

Compression seems very close. all within 10 PSI

The high pitched noise at shutoff is not something Ive heard before. Its happened a few times. Not loud but high pitched and dies off in 5 seconds or so.

I will buy a borescope.

Rob
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Re: Looking for some Help...SBC Oil fouling plug

Post by BillK »

Horder wrote: Wed Aug 03, 2022 8:31 am
The engine is built as a clone of a 66 L79 Nova. The Z28 intake looks similar to the L79 but flows better. Thats why it was used instead, the PCV system is the stock looking system as used on the L79. It was referred to as a closed system
The 1966 "closed" PCV system had a PCV valve that was threaded into the oil filler tube on the front of the intake manifold and a hose that ran to a vacuum port. Another hose went from the back port in the block and ran to the air cleaner. Hence the term "closed" because the breather was not open to the atmosphere. The air cleaner was the breather and any additional blow-by fumes that might escape were drawn into the carb or if the PCV valve became worn-out or clogged. Fresh air entered the back of the block and the blow-by was evacuated out of the front. The oil filler tube was sealed and did not have a breather on it. The PCV valve is not stuck and appears to be functioning. Valve covers are not vented and have no holes.

Rob
Ok,
Pull the pcv hose off its vacuum fitting and plug the end of it. Put a cap over the vacuum fitting so you dont have a vacuum leak there. Start the engine and take the oil fill cap off. Put your hand on it or a piece of paper. There really should not be any vacuum there to speak of. If there is take a can of carb cleaner and shoot about a 5 second shot of it into the oil fill tube. If the idle changes a few second later it usually means you have an intake gasket leaking internally. Normally I do this test at the valve cover hole.

Who assembled the engine ? If its not the intake gasket the only other thing I can think of is if you have the second ring on that cylinder on the piston upside down it will do the same thing. Instead of scraping oil down off the cylinder wall it will scrape it up and it will foul a plug real quick. Ask me how I know :(
Bill Koustenis
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Waldorf Md

www.enginerepairshop.com
Horder
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Re: Looking for some Help...SBC Oil fouling plug

Post by Horder »

Bill:

I will do that test this evening and report back. Thanks for that! Really appreciate it.

The engine builder put the short block together. I installed the heads, intake, valve train etc...

Rob
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Re: Looking for some Help...SBC Oil fouling plug

Post by Walter R. Malik »

Tom68 wrote: Wed Aug 03, 2022 3:05 am Can't imagine enough oil getting past a rocker stud even if you fitted it dry.
At over 19 inches of manifold vacuum on deceleration and the constant running at 12/14 inches of vacuum in the intake port will be the cause of more oil dilution in the cylinder than you evidently realize.
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Re: Looking for some Help...SBC Oil fouling plug

Post by golden_commando »

Horder wrote: Wed Aug 03, 2022 8:31 am Appreciate all of the responses!

here are the answers to the questions

The engine is built as a clone of a 66 L79 Nova. The Z28 intake looks similar to the L79 but flows better. Thats why it was used instead, the PCV system is the stock looking system as used on the L79. It was referred to as a closed system
The 1966 "closed" PCV system had a PCV valve that was threaded into the oil filler tube on the front of the intake manifold and a hose that ran to a vacuum port. Another hose went from the back port in the block and ran to the air cleaner. Hence the term "closed" because the breather was not open to the atmosphere. The air cleaner was the breather and any additional blow-by fumes that might escape were drawn into the carb or if the PCV valve became worn-out or clogged. Fresh air entered the back of the block and the blow-by was evacuated out of the front. The oil filler tube was sealed and did not have a breather on it. The PCV valve is not stuck and appears to be functioning. Valve covers are not vented and have no holes.

Ring pack is Mahle Plasma-Moly ductile 1/16. 1/16, 3/16.

Block had not been previously decked. Machinist/engine builder who built the short block took less than .012" off the decks. No material was removed from intake side. He installed the rings. Hes highly regarded in our city so I would bet its good but everyone does make mistakes.

Vacuum is 13-14 in/hg at 750-800 idle. Seems right to me for a small engine with a 275 adv cam on 110 LSA???

Compression seems very close. all within 10 PSI

The high pitched noise at shutoff is not something Ive heard before. Its happened a few times. Not loud but high pitched and dies off in 5 seconds or so.

I will buy a borescope.

Rob
The noise at shutoff is probably the brake booster losing its vacuum.
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Re: Looking for some Help...SBC Oil fouling plug

Post by Horder »

Test is done and we are learning things....I think

When engine was running I pulled off vacuum line to PCV in oil fill tube creating a major vacuum leak. Engine RPM picked up.
I shut off the engine, capped the vacuum line, removed the cap on the oil fill tube. Started the engine. RPM was lower than when PCV system was fully functional.

I then checked to see if I could feel any vacuum on the oil fill tube. I did not. A piece of paper did not seem to stick to the opening. Even so, I sprayed the carb cleaner down the tube... RPM dropped. Repeated 3 times. Dropped each time. A 5 second shot would stall the engine. Keeping in mind that the cylinder I am having trouble with is a straight shot to the oil fill tube.

I assume my next step is to pull the intake and see where I screwed up. Lol

Again, this help is very much appreciated.

Rob
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Re: Looking for some Help...SBC Oil fouling plug

Post by Horder »

golden_commando wrote: Wed Aug 03, 2022 8:17 pm
Horder wrote: Wed Aug 03, 2022 8:31 am Appreciate all of the responses!

here are the answers to the questions

The engine is built as a clone of a 66 L79 Nova. The Z28 intake looks similar to the L79 but flows better. Thats why it was used instead, the PCV system is the stock looking system as used on the L79. It was referred to as a closed system
The 1966 "closed" PCV system had a PCV valve that was threaded into the oil filler tube on the front of the intake manifold and a hose that ran to a vacuum port. Another hose went from the back port in the block and ran to the air cleaner. Hence the term "closed" because the breather was not open to the atmosphere. The air cleaner was the breather and any additional blow-by fumes that might escape were drawn into the carb or if the PCV valve became worn-out or clogged. Fresh air entered the back of the block and the blow-by was evacuated out of the front. The oil filler tube was sealed and did not have a breather on it. The PCV valve is not stuck and appears to be functioning. Valve covers are not vented and have no holes.

Ring pack is Mahle Plasma-Moly ductile 1/16. 1/16, 3/16.

Block had not been previously decked. Machinist/engine builder who built the short block took less than .012" off the decks. No material was removed from intake side. He installed the rings. Hes highly regarded in our city so I would bet its good but everyone does make mistakes.

Vacuum is 13-14 in/hg at 750-800 idle. Seems right to me for a small engine with a 275 adv cam on 110 LSA???

Compression seems very close. all within 10 PSI

The high pitched noise at shutoff is not something Ive heard before. Its happened a few times. Not loud but high pitched and dies off in 5 seconds or so.

I will buy a borescope.

Rob
The noise at shutoff is probably the brake booster losing its vacuum.
No power brakes. Only vacuum lines are to PCV and vacuum advance
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Re: Looking for some Help...SBC Oil fouling plug

Post by BillK »

Horder wrote: Wed Aug 03, 2022 8:31 pmEven so, I sprayed the carb cleaner down the tube... RPM dropped. Repeated 3 times. Dropped each time. A 5 second shot would stall the engine. Keeping in mind that the cylinder I am having trouble with is a straight shot to the oil fill tube.

There you go. The carb cleaner is getting sucked into the cylinder somehow :) I cant remember who taught me that trick probably 40 years ago but it has come in very handy.
Bill Koustenis
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Waldorf Md

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