Machine Shop Panic!!!

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Hey all, this is the most ridiculous thing I've ever seen..... I had pulled a head off a 80 Fairmont to put on my 69 Mustang 250, then dropped it off a local machine shop to do a valve job and some milling. They told me when I dropped it off that they would clean it then magnaflux it to check for any cracks etc. Then he told me he would call me and tell me if anything needed to be fixed and I could then tell him how much to mill off. Well, I get a call this morning telling me that my head is ready to be picked up and I told them that I never spoke with anyone about how much I wanted shaved off. The guy on the phone then told me they had already done the milling, and I asked how much they had taken off. He told me they took off .14!!!!! He said they had assumed, and just done a "standard milling job". I was going to have them do only .04, as to not shoot my CR through the roof. Is this head even usable now?? If it is structurally sound, and not to thin, does anyone even make a gasket that thick?? Has anyone ever stacked head gaskets?? This makes me sooooo mad!!! I just hope they didnt ruin my head...... Thanks for the help.
 
I would ask them to replace it and take my business elsewhere.

Mine has been at the shop for over a week and we haven't done a thing cause we're waiting for parts (Hey Mike!) for fitment. The shop shop keeps second-guessing me, which I appreciate, as in "are you sure you want us to do this..?"
 
Are you sure it wasn't .014 that was taken off. Most machine shops just take off what is needed so the surface is flat. Unless they are told different.
 
Yeah, 14 thou would probably just take out a warp and flatten things. Mine had a warp of 6 or 8 thou.

If that's what they did then you're probably OK, but communication is the issue.
 
Put it in writing, every time. Fax it, and you will have a confirmation slip. Always add the old rider: Any questions - call, don't make assumptions, or a variant of this. Be available to discuss during regular biz hours and don't drop in unannounced (simple courtesy there).
 
I sure hope he meant .014 instead of .14, but something tells me he didnt. But regardless I should have been called and asked how much I wanted taken off instead of them just guessing... I'd really hate to scrap the head, it took my Dad and I 4 hours in the 115* Arizona heat to get that thing out! Does anyone make a head gasket that thick? Is is even possible to stack 2 head gaskets together or is that just a stupid question?
 
Maybe David Shjeldal or someone can help you calc out the remaining CR to see if you are seriously over the limit with the machining.
 
It had to be .014, if he took off .140 on my head he definitely would owe me a head. No doubt about it, we would go a few rounds :!: I am sure he meant .014. Dennis helped me calculate my cr and it came to around .012 to get me into the cr range I wanted, using the hi comp corteco gasket.
 
Ya I'll just have to call in the morning to find out, I'll let you guys know....
 
Howdy Laxman41 and All:

LAxman- First verify exactly how much was milled from the head.

IF, indeed it was .140" you will be breaking new ground. I've known of a head successfully milled .100", but it was dangerously thin in critical areas. .090" is a big a cut as we would ever consider and then only with sonic testing to verify no thin casing spots.

014" is within the "Normal" range for truing the mating surface on a builder head.

Know that an '80 head casting will have the same large 62 cc chambers as the '69 250 "M" castings.

What is your compression ratio goal for this engine?

Darwin- Please tell me about the "hi comp corteco" gasket. I only have details on Fel Pro, Victor/NAPA, Fomoco composites and steel shim head gaskets. What type of construction? How thick? etc....

Adios, David
 
Ya, I called this morning and it did turn out to only be .016 not .14, like the machine shop originally told me. It seems some people nowadays cant use the decimal system they learned in elementary school... But thanks for the help anyways guys. The Corteco High Compression gasket has a crush thickness of .038 correct?? If I used this gasket with the head the way it is now (at .016), I'll get just above stock CR right?
 
Glad to hear you still have a usuable head. I don't know enough to give you advice on your cr-ratio. I am estimating based on Dennis and David's book that .005 takes off approximately 1cc per chamber and .050 takes off about 10cc's a chamber. If you have a piston to deck height clearance like mine 'about .013 at TDC and you add the thickness of your gasket 'say the .038 corteco gasket and you add these together you get around .051 (approx. volume of 10cc and if you add in the 7cc for dished pistons---if you have them then you are looking at 17cc to the deck plus what ever the space is around the outside of the piston (maybe 2 to 3 cc's or so) "I am estimating here". You then have to consider what your combustion chamber size is 'mine is around 53cc on average per chamber. Now take all of this (using your numbers not mine) and go to dennis's website.

http://falconperformance.sundog.net/compcalculator.asp

It will tell you what you need to get your compression ratio and you can get a fairly close estimate of how much you need to mill and/or what thickness of gasket you will need. Then do like I did and get Dennis or one of these smarter guys to double and triple or quadruple check your figures. :) Just to clarify one point---in the piston to deck clearance category don't add the gasket in as I did in the upper paragraph---the calculator does that for you---just put in the clearance from piston to deck. In my case it was .013. I hope I haven't thoroughly confused you. In my calculations .015 removal equates to about 3cc's per chamber--but check this with others here.
 
He was just trying to help you cut weight. Hah, good thing it wasn't true.
 
Ya, but I'm a skinny white kid so I dont need any extra weight savings ;) Just got the head back the other day and it looks nice and its ready to go, I just need gaskets and headers....

But I have another question, will the stock pushrods work or do I need shorter rods??
 
Howdy;

Between the thicker aftermarket head gasket and the hydraulic lifters you should be just fine with your stock OEM pushrods.

Did you ever check the difference in thickness of the head gaskets?

Adios, David
 
Thats the thing, I've never heard a definitive answer on the thickness of the stock gasket... I knew they were thin metal things, so I've just always asumed .025. Is this anywhere close??
 
Howdy:

.025" is typically compressed thickness for a stock OEM steel shim type gasket. If the replacement gasket is an aftermarket composite type know that it will be .045" to .055" compressed thickness- And you should have milled an amount equal to the difference between the old and new just to maintain stock CR. That is .020" to .030". At at a mill cut of .016" you will lose CR. (Not much) and you will actually have more clearance for your lifters to make up.

Adios, David
 
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