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Head milled incorrectly?

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gofast63

10+ Year Contributor
382
28
Apr 22, 2011
Manchester, Michigan
Hey guys, I just had my head milled and I'm getting different measurements. This was a almost perfect head before I gave it to them. The reason for getting the head milled is I had a chip in the combustion camber in cylinder four. Here are the measurements. I think they forgot to check the head to see if it was leveled first. Also they told me they only took off .006. Would this be ok to run?
 

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You have a variation of almost .010". Hell the f*** no I wouldn't run that head. Even for a composite gasket that's too much variance.

*edit* I just realized those are thickness numbers. Take a precision straight edge and measure lengthwise in 3 sections to see if the surface is still warped. Then measure diagonally corner to corner. Then in between the combustion bowls. If you can stick .003" feeler gauge underneath I wouldn't use it.
 
I know its not warped. I can't find my feeler gauge to check it for shit and giggles. Any other options. It was $380 to get this head done. I need more advise before I contact the BBB.
 
You know its not warped, yet you are saying that you're worried about the different thicknesses? I'm assuming you just used calipers to get those numbers around the perimeter yes? The advice above to use a straight edge and a feeler gauge across the surface of the head would be the best way to identify potential problems with sealing. Even if they used a belt surfacer and the head is at a slight angle giving you a slightly larger combustion chamber on one end compared to the other, if its still flat you shouldn't have issues it just won't be perfect. If on the other hand the surfacing process left high and low spots and you can slide that feeler gauge in, prepare for some trouble...

If in doubt, take it back to the shop and make them show you how they identify that it is true. If its not, they better stick it back on for another pass to clean it up assuming there is plenty of room left to still be in spec on the height.
 
I agree with all the above comments and would recommend looking up some of bogusSVO's tech articles on head work.

Just make sure to check the head out before you get on to the shop. I have seen some pretty crappy work done from shops (its like they look at our dsm stuff like its alien technology or something) and yes it is possible they screwed it all up but just make sure you know they did.

A local shop I have taken stuff to has no idea what I want done or how so I have to tell them everything exactly how I want it. They do good work but have to be instructed on all specs, tolerances, and what not to do. I only use them when I have no choice and can't wait to send stuff to a real dsm shop. Best bet is to send your stuff to a respectable dsm shop like some on here. In a pinch you have to use a local shop more than likely they will need all instructions of what to do and how. Write them a book. LOL
 
By the numbers it looks like this was done with a belt surfacer, as the head is placed on the table it rides against the end of the table and usually more force is applied to the free end, that is indicated by the low numbers on one end.
The head is probably straight and the feeler gauge method would not apply since there are no low or high spots, it is at an angle, by the numbers and their sequence, it could affect the cc volume, I would try to get some money back in order that you could take it to another shop with the proper machinery
 
I used a digital calipers to measure and just used a metal ruler as a straight edges with a feeler gauge. I need to find another straight edge though ( I measured it the second time and flipped the ruler around to see if i would get the same results, Failed) I'm sick to my stomach because this was a virgin head. I do have a spare, but still. I didn't even check the valve job because I was so pissed. Before I had this machined, the surface was well with in spec. So this makes me think that they didn't have the table level before they milled it, correct? what do you guys normally used for a straight edge?

Thanks
 
By the numbers it looks like this was done with a belt surfacer, as the head is placed on the table it rides against the end of the table and usually more force is applied to the free end, that is indicated by the low numbers on one end.
The head is probably straight and the feeler gauge method would not apply since there are no low or high spots, it is at an angle, by the numbers and their sequence, it could affect the cc volume, I would try to get some money back in order that you could take it to another shop with the proper machinery

Here are some pics. It looks like they milled it. What do you think?
 

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Find out what type of equipment they use, if a belt sander the table could be level but still the pressure applied to the head would be by hand.
Machinist ruler are not cheap.
 
If i have the head leveled off to 5.180 could i even run it? I'm going to need this car to last when I'm done. I would like to keep my spare head a spare. I've read a lot of bogusSVO threads over the years. But hes even seen our car run and drive with the head 5.160! Not sure how they would make up for the timing loss.( probably adjustable cam gears). I just don't know what to do. Use my spare and try to get my money back or try to work with this and see if they can give me a discount.
 
I'm sure you can work with the head just fine, worse case you can use a thick HG and gears but I doubt you'll even have to go that far. Are you planning on some crazy cams and OS valves? If they use a real machine then they should be able to line up the head again properly and shave a few thou each pass until the high spots come down to the low ones. If they directly told you that they don't use a belt surface setup, it would seem that they are completely incompetent to machine it off axis or maybe the head was already screwed up from the previous build, you say its a virgin head, but that doesn't mean it was perfect going in? If they gave you back a flat surface, just off axis at least the machine works they just didn't set it up with enough care. Talk to them and get some answers, and be sure to politely ask those Q's as most machinists I've known are hard headed and don't like to admit mistakes!
 
Here's jafro's head checking vid:
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I think the poor machinist missed a shaving or two cleaning off his table that got pinched between the backside of your head and the table. Things happen & he could even have found it when checking his cuts. I feel sorry for machinist though. Unlike everyone else, they don't have an eraser or an undo button. They don't have extra parts. They make their living playing cut throat on everything they have to do. I'd be nice because their job is a bi*** and you'll have a better of him wanting to try & help & what he can do.
 
I'm sure you can work with the head just fine, worse case you can use a thick HG and gears but I doubt you'll even have to go that far. Are you planning on some crazy cams and OS valves? If they use a real machine then they should be able to line up the head again properly and shave a few thou each pass until the high spots come down to the low ones. If they directly told you that they don't use a belt surface setup, it would seem that they are completely incompetent to machine it off axis or maybe the head was already screwed up from the previous build, you say its a virgin head, but that doesn't mean it was perfect going in? If they gave you back a flat surface, just off axis at least the machine works they just didn't set it up with enough care. Talk to them and get some answers, and be sure to politely ask those Q's as most machinists I've known are hard headed and don't like to admit mistakes!

It's a stock build. The head was inspected before going to the machine shop. The head was straight as it could be. The only problem was that there was a chip of metal missing on cylinder four that connected to the head surface.
 
I think the poor machinist missed a shaving or two cleaning off his table that got pinched between the backside of your head and the table. Things happen & he could even have found it when checking his cuts. I feel sorry for machinist though. Unlike everyone else, they don't have an eraser or an undo button. They don't have extra parts. They make their living playing cut throat on everything they have to do. I'd be nice because their job is a bi*** and you'll have a better of him wanting to try & help & what he can do.

I don't have any intentions of being a dick. It's just going to make the situation worst. What irritates me is that he told me he only took .006 off. But if I had it leveled off to 5.180 what head gasket do I need to use? Or would the head still be useable at that point?
 
Mello: No offense but in my line of work there is FAR more pressure and no "undo" button either. When a mistake is made the company or individual responsible needs to step up and repair or replace the affected component. I dont necessarily feel sorry for the machinist, i feel sorry for the dude who just got pounded for upwards of a grand. The machinist lost NOTHING, financially.
Ive had bad machining cause failures THREE times now. It really is like the 4g63 is from another world, as stated above!! WTF?

OP: If it is what you think it is then have him show you it is fine, while you watch him measure and explain each measurement. Thats gonna make him very uncomfortable. Let him do all the talking. Stay as quiet as possible and leave those uncomfortable silences in there! Ask a question and just sit back and relax. Basic psychology. If hes not savvy, he'll cop to his mistake and offer you far more than he would if you immediately go on the offensive.
 
I don't have any intentions of being a dick. It's just going to make the situation worst. What irritates me is that he told me he only took .006 off. But if I had it leveled off to 5.180 what head gasket do I need to use? Or would the head still be useable at that point?
http://www.dsmtuners.com/threads/how-to-measure-a-4g63-for-cylinder-head-for-thickness.413757/

You're out by at least .005". From a quick view, Cometic and HKS makes a 1.6mm thick MLS gasket. Should work for you. Felpro has their MLS thickness at .055. Power Enterprise makes a 1.5mm thick MLS.
 
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