New day New Problem--1988 GM 5.7/Cobra oil at the plug wells---

[ab59]

I noticed after my break in oil change that I seemed to be using or leaking oil. When I changed the cap rotor and wires I saw what was to me an alarming amount of fresh oil in the bilge. I cleaned the bilge and started the engine running on muffs in its stall . With a good light and engine running , I inspected the Pan and drain plug and hose but found nothing. I looked up and saw that the plug wells had what looked to be fresh oil on them and it appeared to be weeping quite a bit . Not squirting but a steady oozing and the oil did not smell like gas so I tightened up the rocker arm covers and re checked. the oil at the plugs seemed to be stopped or significantly slowed but then I noticed that # 2 plug was bubbling at the threads . I have NGK tapered Plugs in the engine they have no O ring but are tapered with no seal .
I am not sure that tightening the covers stopped the problem of the oil leaking but since it slowed it down at least , I will pull the covers and dope up the gaskets . I am more than a little concerned about the bubbling at # 2 however.
Do you guys think that I should dump the new NGK plugs and go back with the regular thread plugs with a seal ? If so What Plug would you recommend for this year engine . I have some information that the timing should be set at 3* BTDC to burn 87 % gas , what would the consensus on this be ??

 

[Lou C]

No plugs for Chevy small blocks use a gasket, at least none I’ve ever seen, they use taper seat plugs. Are you sure those are the right NGK plug for that engine? I always used AC marine plugs in mine...

 

[ab59]

Hey Lou , thanks for your reply--- I bought the Plugs Represented as being for a 1988 GM 5.7 OMC but of course that does not mean that they are. They thread in just fine and snug down good . Is there a remedy for the bubbling at the threads short of something drastic like Helicoils ?

 

[alldodge]

Instead of NGK I would suggest MR43T

Bubbling on threads is just the oil getting hot (right?). Now if the is combustion gases escaping then you need a new head. I would not use helicoils, just not enough room form the threads

 

[Lou C]

yes that is odd, any problem with the threads? Bubbling suggests combustion gases are leaking past the threads...
Are your valve cover gaskets leaky?
In the old days when we had the perimeter bolt valve cover gaskets made of cork they always leaked, the modern center bolt ones with the OE or the Fel Pro gaskets rarely if ever leak.

 

[ab59]

First off thank you both for your replies ---- I went out and cranked the rocker arm covers down a little more and then dug out a torque wrench and went through the plugs . I loosened them first and re tightened them to 18 ftlbs. I found that for some reason that about 1/2 of the plugs were not tight at all ???? Odd because I installed them with the engine out of the boat and torqued them to spec then as well . I just finished running the engine on muffs again for 10-12 minutes and I don't see the problems of the leaking oil or any bubbling . I do not like the way that these NGK plugs feel with they tighten up , there is just something that does not feel right about them. If I have any more problems with them loosening off I will just replace them.

 

[Lou C]

I've changed plugs on Chevy small blocks many many times and all had taper seat plugs and I just got them snug and then maybe a 1/16th to 1/8th turn more. Never used a torque wrench. The loose plugs explain it. Maybe the way they are tightening up is fooling the torque wrench into reading correct torque when its not.

 

[PITBoat]

I pulled the plugs on my 400sbc the other day, and man some were really tough to break loose. My 14 year old had cleaned them for me last time, and got carried away when he put them back in.

I agree there's a correct feel to when it's right that equates to easy to get back out, but no leaking either.