Help! Oil on exhaust manifold bolt & spark plug???

[retired ralph]

74 350 SB. I pulled the 3rd manifold bolt off to detail the A/C bracket and it had oil on the threads. #4 (2nd cyl. on right.) Also the spark plug had oil on it. The good news is the compression is 170! Iam hoping it's only a head gasket. The engione was rebuilt around 15000 miles ago. Let me know your opinion. Thanks Ralph

 

[Crimson Thunder]

Could be just a leaky valve cover gasket.

 

[GRAND SPORT #12]

I would start too with valve cover gaskets since is common to leak

 

[retired ralph]

Not a valve cover gasket

The oil on the bolt is at the tip and the plug has oil at the spark end in the cylinder. I guess I'll have to pull the head. Any advise? Thanks for responding. Ralph

 

[damoroso]

I saw this in another post with pics. You don't have head gasket problem, at a minimum you have valve seal issues. As I recall, all the plugs looked the same right? That being the case, it's either the valve stem seals or probably more likely, rings were installed upside down.

 

[Hib Halverson]

Whoa, whoa...
If the rings were "upside down" the engine would not only burn oil, but a lot of oil, like...a quart every 100 miles or so.

A little oil in the tip of an exhaust manifold bolt is nothing to worry about. If the spark plugs have been in the engine a while, oil on the threads below the tapered sealing service is common.

The important question is the engine's oil consumption. You said you had the engine rebuilt 15,000 miles ago. Since then, how much oil have you added.

 

[retired ralph]

Oil consumption

I have added about a 1/2 quart every 3000 miles. The #4 plug is the only one with oil on it. I suspect its a valve seal. I hope!

 

[Hib Halverson]

A quart every 6000 miles?

You have no oil consumption problem. Put the exhaust bolt back in then wipe of the plugs and reinstall them.

As I said earlier, a little oil on the bolt end and oil on the plug threads is not unusual.

 

[damoroso]

Hib, your not getting "The rest of the story" here. The OP posted this issue on another site (nothing wrong with that) and posted pics of the plugs. They were oil fowled pretty badly and wet too. He said all of them were like that. That's why my thought is that there might be a valve stem seal problem or one of the rings on each piston upside down. If it were only a manifold bolt, I'd be suggesting valve cover gaskets and such...

 

[Hib Halverson]

The engine discussed here on the CAC does not have an oil consumption problem.