300 4bbl Spark Plug Threads

M

Matty-boy

Member
Hi - I noticed one of my spark plugs went in a little funny today. Turns out that the threads on the aluminum head went south. I want to do the thread insert thing but don't want to leave any metal in the cylinder. Has anyone inserted the thread inserts? How did you make sure you didn't get any metal inside? What is the trick? Yes - I know I can take the head off, but to be honest - I'd rather not...
Any suggestions on tech tips and or parts manufacturers?

Thanks,
Matty-boy

1964 LeSabre convertible
 
You are never going to be able to do it without getting some metal in the cylinder. Luckily aluminum is soft and shouldn't do much damage while it's blowing out the exhaust after you re-fire it. If you use a "Heli-Coil" style insert they recommend that you pack the flutes on the tap with grease to hold the shavings that are cut off while you are screwing it in. You could try to roll that cylinder around to where the exhaust valve is open while you are tapping for the insert and then try to blow a bunch of compressed air through the spark plug hole when you're done to try to blow the cuttings out into the exhaust manifold before you fire it. Make sure that only the exhaust valve is open and not the intake as that will just blow stuff up into the intake and possibly into other cylinders. There are several brands and types of repair inserts available. All will work if installed properly. Are you using an anti-seize on the spark plug threads when you replace them? This is very important on aluminum heads. If you use it and never over tighten the plugs the threads should never give any problems.
 
I'll give it a try

Thanks, I'm headed to the parts store today. Didn't use anti-seize just oil on the threads. The exhaust valve and compressed air sounds like a reasonable approach. I will let you know how it works today.
I just bought the car in January - this was my forst plug change (among many (many) other things).
Thanks again,
Matty-boy
 
Rivvy
thanks for that tip on using anti sieze for alum heads.

I was going to suggest bringing the piston to TDC, stuff a piece of oil soaked cheese cloth into the cylinder - something you could get hold of with needle nose, plus having the shop vac running next to the tap..

I hope i dont run into that problem - I'm just putting the 310 back together
:shield:
 
Matty-boy said:
Yes - I know I can take the head off, but to be honest - I'd rather not...
1964 LeSabre convertible
Click to expand...

I would *NEVER* do this unless the head was off. I mean, really,
how much extra hassle is it to remove a head on these cars,
versus the painful result if things don't go as you wish.

There's a right way and a wrong way to do things. Leaving the
head on and installing a heli-coil is, IMO, the rwong way.

If it were my car, I'd yank the head and bring it to a shop and
have them fill it in, bore, and tap it - i.e., no heli-coil.

Of course, we're talking about your '64 LeSabre convertible
and not my '64 LeSabre convertible :)
 
You are right

In thinking about this... you are right. In fact, I have the head in the back of my Trailblazer now. I am bringing it into the machine shop today.
If you're gonna go - go - don't go halfway. I have some questions about your '64. I'll email you later...

Thanks again everyone...
Matty-boy
 
Rivy Has It Right

It's off now but I've done Olds and Buick 215's and 300's his way. Most of the meat is striped out anyway. Be sure to use full length 44FFS plugs or you'll be doing it some more.
 
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