Issues with shaving .018in off of my head?
 

So for some background information I have a fairly stock '99 miata with 136,000 miles on it. This is the second time Ive rebuilt the engine on this car. In between now and the last time I rebuilt the engine, the engine has become warped, most likely from oil getting into the coolant and causing the hoses to weaken and break causing the engine to overheat a few times.

Now Ive just received my engine back from the shop after getting it machined, and was also given the news that the shop had shaved .018in past spec off my head and .005in off of my block and that I needed to order a .02in spacer to get my engine back under spec and that it would not run if I did not do this, they told me that they had a few Honda engines where they shaved their heads and they had problems running.

So I started doing research to see If our engine's are the same and if it would cause problems with my engine. but so far most to the info I have found has to do with 1.6's or guys that are running e85 and have engine management and such. I understand that it will raise my compression to 10:1 and that I may have to start using 91 octane gas and my timing maybe a bit off but should I have any other problems? or should I be fine and not worry about it and gain a little hp at the same time.

Thanks

That is way too hard to read. Rewrite your question with proper paragraphs, punctuation etc., and we will be glad to help you.

What you have written does not bode well here.

It would be fine if you were talking a good head and decking it .018" to raise compression. If a head requires that large of a shave to eliminate warping, the cam journals are bent too and even if you heat and straighten the entire head, it's likely to simply re-warp as soon as it gets hot again.

Your machinist is an idiot, you should never install a spacer to compensate for a decked head, since it just increases squish clearance and causes other issues. Since he didn't know this, I'm not so sure he knows that you can't deck a heavily warped head. It might be time to find a new head, and it's definitely time to find a new machinist.

>2014 years after the birth of our lord and savior
>spacers

Agree with needing new machinist.

Thank you Reddon for editing your post.

Your question has already been answered. The prices are starting to rise on Miata parts, so the sooner you find one the better.

If you think you will stick around this forum, make an introduction in the Meet and Greet.

Good luck.

Thanks to everyone that has responded I appreciate it.
I forgot to mention that my machinist used a hydraulic press to straightened the head out before shaving it. Would that have fixed it enough so that it will not warp again and should it be fine to put together without the 0.02 shim? I ended up calling my machinist, to ask him some questions and he said everything is will be alright and advised that I should use the shim because he felt that with the head being shaved the timing would be to far off and unable to run and that the compression would be to high.

I did some research on the matter and all I could find is that it would maybe retard the timing 2 degrees at most and have a CR of 10:1. Would that be a huge problem?

Thanks in advance

u wot m8? are you serious? isn't this usually used for engines where coming across a new cylinder head is almost impossible, old italian cars, etc.?

i would seriously just pick up a new head.

eeeerrrrrr ahhhh... thats not the normal procedure for straightening a warped head...

Thanks guys! New head it is then :(