Re: Anyone ever pop a head gasket?

[Jack H.]

If your '66 is a small block, did you replace the press-fit rocker studs with screw-in's when the heads were rebuilt? It's not uncommon for pressed rocker studs to begin to 'lift' with the worst consequence being swallowed valve(s)....

Easy to check...pull the valve covers and sight horizontally down the line of rockers. Are one or more 'high' compared to the others? If so, STOP driving the car, pull the heads and return them to the machine shop that did the work for you. I personally don't trust anything other than screw-in studs for these used/classic head castings. But, standard studs can be pinned....

[Mike McKown]

I'm just kinda' curious how "pulled" rocker

studs can cause you to drop a valve?

I guess I'm also curious why you don't trust the factory pressed studs. Once you got past the early '55 V-8 with the short studs, I don't recall any particular problem of any significance with the studs lifting.

Please advise.

[Gary #41345]

Re: Anyone ever pop a head gasket?

The car had some engine work done on it by the previous party who had it before I bought it in the Jan. of 2004, all efforts on my part to find out who did the work...(new valve seats etc.) and what exactly they did came up blank after many calls and inquiries. It's the last thing I expected though was to find oil on the spark plugs after a period of rough idleing over a week/week and a half period..... Reading a past post by Sean Blake on Sept. 5 at 4:32pm is similar to my situation...which by no means takes away from the severity of the problem. Right now I'm hoping for the misalignment theory to be the extent of the problem...... Should have maybe looked at that oil pump also that liked to always read between 50-60 psi but I just figured they installed a higher pressure pump and left it at that. The adventure continues....

[G B.]

My experience

I've encountered only a few SBC press-fit rocker studs that were starting to pull out. Those were caused by aftermarket Zoom valve springs with God-knows-what seat pressure. The high spring tension caused the studs to lift maybe an eigth inch or so. Of course the valve lash increase was the most obvious symptom of the problem.

None of these studs pulled completely out. It would take a...umm...less than smart...owner to continue to tighten the lash until the stud came all the way out. I'm not even sure that's possible with the valve cover in place. It would be possible, however, for the rocker to become so loose that it would start to press on the valve keeper occasionally rather than the top of the stem. I guess that could release the keepers. Maybe.

I still don't understand how a pulling stud would lead to a blown head gasket, but possibly someone else will explain that to me.

[Bill Stephenson]

Re: My experience

-----Big Pontiac motors are known for pulling studs out. I had to yank the heads on my 421 and have them all pulled and threaded. Actually used big-block Chebby rocker-arm studs. I guess this is fairly common in Pontiac land but cant say for small block chebbys.........Bill S

[Gary #41345]

Re: My experience

Seems the noise and idleing condition I was speaking about was the distributor after all......doesn't make the noise right away on start-up but within 3-5mins of running time..it does. Anyways my mechanic checked it out and time for a new distributor tomorrow.....imagine that could lead to some oil on the spark plugs if the firing sequence is being compromised.

[Mike McKown]

I gone to bed late the last two nights,

guess this is why my head is spinning. I can't for the life of me figure out what's going on.

[Gary #41345]

Re: I gone to bed late the last two nights,

Mike, I pulled my spark plugs after about three weeks of use because the motor was starting to run rough.....you could hear the misfiring out the exhaust and found oil along the threads of each plug. On a trip to a local car show last friday night a noise started from the engine compartment that didn't sound very motor like...almost like a rubbing sound but loud that started and stopped frequently. This noise was nonexsistant when the motor started but came as it heated up.....to make a long story short it ended up being the distributor and now I'm assuming that the fact that I was in the process of losing my distributor that must have lead to the oil around the threads of the plugs. I pulled my first post on this topic which at the time I believed I may have had a cracked head gasket or worst...sorry for the confusion.