okay I just want to start off by saying that if I can't get this issue fixed I am just gonna give up on her. ok maybe not but I am mad right now, I am supposed to be at the Corvette races at Capitol Dragway but instead ..

Little info on the car it is a 1980 with a crate motor dropped in there heres the important parts the crate motor is the "385" fast burn 350 motor.
Aluminum Vortec heads that have angled spark plugs
all the internals are still set from factory
750 cfm holley carb
ummm. sorry I am tired thats all I can think of right now that might be relevant

Ok heres the problem about 2 months ago I had a spark plug rattle loose in the head and blow out while driving down the road. Now I'm not so fanatical that I pop the hood and check everything out every time I start the car but I do work on her a lot so I am usually under the hood once every 1 or 2 weeks. after that occurred I took it to a shop had them drill, tap, and Helicoil the hole so now it works good. Today I go to the car haven't ran her in a while about 3 weeks (I have started her once a week though) walked around the car listening for new sounds or anything and popped the hood to see the front left spark plug shaking.

I really don't want to have to pay for all that work again does anyone have any recommendations to hold these things in any better they are Autolite spark plugs I don't remember exactly what kind but if it is relevant go ahead and ask and I will see what I can dig up around here.

Like I said this has already been a Thorn in my side once and really would like to put an end to this those aluminum vortec heads are pricey and I like them but I don't want to pay for them.

 

I am not a mechanic, but it would seem to me you are not tightnening them up enough.

 

yes.
get a torque wrench and practice, even if u can't use it on the plugs u will be closer.
i use anti-seize as they are more likely to get stuck, than loosen.

 

Possibly but then my concern is stripping the threads.
Does anyone know the torque rating on aluminum vortec heads???

 

I know nothing about vortec heads but,

do you need plugs with built-in crushable washers?

 

that would be good but I don't know if they will work with what I have or not I think I am just gonna call Jeg's or someone like that and ask about the heads and what kind of plugs to use with them.

 

The 80's heads will take a plug with a angled seat not the crush washer. What plug # are you running?
A Helicoil is a stainless steel thread and will hold better than the original aluminum.
You might still be able to strip the helicoil from the head but thats doubtful

 

crate motor so specs from an 80 vette do me no good no offense and it is a different plug this time then the one repaired with the helicoil

 

I would think the spark plug boot would be enough resistance to keep the spark plug from backing all of the way out of the engine. I have never heard of a spark plug backing out to the point that it blew out of the engine.

Something doesn't add up.

BigBlockk

Later.....

 

My guess is that the plugs were tightened too much when they were first put in...and the threads were stretched and damaged. Aluminum and steel [together] don't require as much torque as steel with steel. The aluminum isn't as strong of a material; and the dissimilar metals "grab" each other. If a normal torque (for steel heads) was used to install the plugs, the threads were likely damaged. You may have to helicoil them all. {I would have thought that the heads had instructions that told what torque to use...}

 

Ran into something like this.....question, IF the engine has/had a somewhat sloppy idle, kind of raggedy but no known reason....

check that the plugs you are using are not the angle bevel type sealed ones,....in a head with longer shank...aluminum threads being deeper, and using a washer.....

dont ask.....

 

I know it sounds odd but thats actually exactly what happened the first time driving down the road at about 35 MPH and had been hearing a popping of air sound I thought it was a leaky exhaust checked it out and the plug was loose decided I would try to tighten it in a parking lot and gimp it home tried and it wouldn't tighten just kept spinning, already stripped but it was holding (odd huh?) drove about a mile on it and the plug came flying out still attatched to the wire landed on the brake fluid container

unfortunately I am just going off of what I can collect cause like I said this was a one peice crate motor and I haven't done any hardware swapping. the only way I know what plugs to use are I am using the same ones I pulled out of it so I hope I am using the right ones but like I said I am gonna call up Jeg's today and ask them about the specific heads.

my idle has always been kinda sloppy but I think that has to do with my timing not so much with my spark plug sitting where it is sitting but I could be wrong.

 

MY problem was I had a set of iron heads 993 I think, and they took a certain plug with short threads and a bevel on the body seal area.....

but the 113 aluminum heads needed longer plugs with washer on theim....so the engine ran, but sloppy as hell....plugs damn nearly 1/2 inch too short...but then again, you sure as hell don't want anything too long either....get hold of the head maker and find out WTF you need put in there, that would be my first move at this point....

 

Thank you very much Mrvette for the advice I think I am gonna call Jegs right now and ask them after all I am at work and there is nothing more satisfying then burning up company time instead of mine

By the way I am still all ears for more advice or recommendations

 

Ok gentelmen heres the verdict, I called jegs and they said they recommend an:
Accel 111-526

or any spark plug with-
460 reach
14mm
and 5/8 tapered seat