Head milling

giddyup306

Registered User
I'm putting new head gaskets in my 89 so I decided I might as well have them milled (they're probably warped a little bit anyways). My question is how far can i go (as far as compression) so I can still run 87 octaine.

Thanks all

Mike
 
I believe you can go down 0.020 before you run into valve/piston clearance problems. Take them down about 0.010 if this is the first time you have had them milled. Do you own a dremel tool with a cutting bit and a polishing bit? You can port the exhaust and polish it yourself to match the opening size of the gasket for the exhaust manifolds. Also change the valve stem seals and freshen up the valve seating surfaces with some valve grinding compound.

87 octane? You better be talking about a 3.8L N/A bird and not an SC. If you run 87 in your SC, well I will just say its not too bright. Kinda like pissing on an electric fence.
 
you you are putting 87 octane in an SC, thats why your headgaskets blew.... next you will probably either blow them again or blow a hole in a piston. put 91+ in there asap.
 
typically...

Typically when heads are milled they only remove enough to make them flat again. Which can be as little as .002 or as much as .005 of an inch. Be sure the place that does the milling puts a very very smooth and slick cut on them.

If it were me and you are going to the trouble of having the heads milled send them in for a full valve job as well. This will reface valves, recut the seats, install new guides that could be worn out, and replace the valves seals themselves. Typically around $150 - $200 for both heads with the resurface.

Chris
 
Here is a piece of an article from a previous Chargin Thunder :::

So now you know what a head gasket is and what it does. So why do they fail? Well, here is a list of common causes. Ranked by what I saw at the shop.

Overheating. By far the most common. Could be as simple as a defective $5 thermostat or a plugged radiator, but run the motor hot and bad things happen.

Detonation. This could be a result of low octane fuel, carbon buildup, too much ignition timing, or overheating. A combination of these will produce failures in a hurry. In the combustion chamber, the only thing that keeps the pistons from melting is a small layer of gas that "clings" to the piston dome. Detonation sends a shockwave and flame spike through the cylinder that rips this layer away exposing the actual metal surface to the combustion temperatures. My head gaskets failed from detonation. The detonation actually split the fire ring. Severe detonation can burn holes through pistons too.
 
The head gaskets were out when I bought it. I just picked up the car like a week ago.

Also I thought you could run 87 octaine in a sc because

A) they have aluminum heads
B) they have intercoolers
 
Nope, 91 Octane minimum unless you pull the octane plug to retard timing or remove the supercharger belt.

87 octane and forced induction don't go together.

David
 
octane

Well did you guys know that some areas you can run 87 with no problems. Why? Well not all places rank the gas the same and the octane rating is actualy higher. They list that as the lowest it could possibly be.

Also different areas the gas is different and has a much higher rating than is listed.

I will try and find some of the places I have seen it.

Crazy XR7
 
REGARDLESS 87 oc is a no no..Hell maybe it will work 110 ft below sea level..WHo knows :O)..Run premium man..You haev no choice!
 
ainnn't worth it

i'm helping my friend replace his head gaskets (in an unheated barn in the winter!) and one thing he did that very likely contributed to it, was use 87 a few times. i myself used it one time and my car jsut didn't feel right...something felt wrong, so i never did again, now i'm glad i felt that!!! what's a dollar or two every few weeks to save you all the trouble (and/or money) of tear ing apart your engine?? think of it as cheep insurance ;) take care everyone! :)

DrFish
 
Damon Slowpoke Baumann said:
REGARDLESS 87 oc is a no no..Hell maybe it will work 110 ft below sea level..WHo knows :O)..Run premium man..You haev no choice!
Like I said I've never put any gas in the car!! I only drove it on the trailer then off the trailer finally into the shop!
 
Re: octane

hepcat said:
Well did you guys know that some areas you can run 87 with no problems. Why? Well not all places rank the gas the same and the octane rating is actualy higher. They list that as the lowest it could possibly be.

Also different areas the gas is different and has a much higher rating than is listed.

I will try and find some of the places I have seen it.

Crazy XR7

I noticed you are from NE too. Are you going to the get together the 15th in Lincoln??
 
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