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-   Engine Performance (https://www.miataturbo.net/engine-performance-56/)
-   -   Bought a 99 head with bent valves. Input needed. (https://www.miataturbo.net/engine-performance-56/bought-99-head-bent-valves-input-needed-65656/)

Tyler01 May 17, 2012 09:30 PM

It wasn't warped, there was a nick that extended into the combustion camber on #4 and out into the circumference where the HG seals. The plan is to do a stock rebuild with 99 head, msm intake cam, 01 pistons with arp main and head studs, with acl bearings. The cams will be degreed upon assembly to alleviate any miss- timing of the valvetrain/rotating assembly. It was prep'd for a MLS HG, the machinist that did the work does the machine work for all the local dealers, so I have no worries.

I will post a pic of the finish if you would like, but my camera isn't the best and I doubt it would have enough clairty to see that fine of detail.

BogusSVO May 17, 2012 09:50 PM

Ok

Do your surface finishes look like this?

https://www.miataturbo.net/showthrea...818#post863818

https://www.miataturbo.net/engine-performance-56/how-deck-4-cylinder-engine-block-64577/

Tyler01 May 18, 2012 09:03 AM

2 Attachment(s)
Here is the best pic I could get of the surface

BogusSVO May 18, 2012 10:54 AM

Your head has been belt surfaced..... Sorry I would not run a MLS gasket with that.

https://www.miataturbo.net/engine-performance-56/why-not-let-your-head-belt-surfaced-64394/

Tyler01 May 18, 2012 11:35 AM

Well this sucks. Its had to much taken off to take anymore, So it looks like im back at square one, unless you know of a fix.

flounder May 18, 2012 11:45 AM

If you're going turbo or plan on it in the future, why not throw in some $200 h-rods while you have it apart? Almost silly not to do so.:brain:

BogusSVO May 18, 2012 12:21 PM

if you stay NA having another .005-.010 will not hurt, just bump the compression some more.

But if turbo, find another head, or get a custom thickness (cometic) head gasket

Tyler01 May 18, 2012 04:36 PM

Thanks BogusSVO for all your input. I'm staying NA for sure, when I find another machine shop around here that will do this properly- I'll post another pic of the finish and the amount removed and so forth.

BogusSVO May 18, 2012 05:27 PM

I posted this for you

https://www.miataturbo.net/showthrea...191#post879191

Measure your head and see where you are.

Tyler01 May 25, 2012 10:26 PM

Sorry for taking awhile to reply, my wife and I just got back in town the other day.

Looks like I'm back to square one,
Measurements are:
IF: 5.223
IR: 5.220
EF: 5.241
ER: 5.241

While I don't fully trust my calipers- they are a dial type, that was given to me by my grandfather and they don't always return to zero when you close them up. I did the best with what i have, zero'd them before each measurement and closed them afterward to ensure that "zero" was maintained. Also beforehand I measured a few feeler gauges to make sure they were still some what accurate. That being said I will NEVER use these for any sort of engine assembly- these measurements are way below the minimum thickness. The variation from Intake to exhaust side is supported by the "tabs" in the picture. They are the cast circles on the head that presumably tell you that you are stupid and machined the head to far. Notice that the one in the foreground of the picture has clearly been ground down while the one in the background still hasn't been machined at all.

BogusSVO May 26, 2012 10:15 AM

The tilt in the head is from the way the machinist applied pressure to the head when he had it on the belt surfacer.

The tabs you speak of are not milling stop points,that is a wives tail, they are injection points from where the aluminium pourd into the sand mold of the head.

On the dial calipers, blow som compressed air on the teeth, sounds like you have a piece of grit in there that causes them to skip, that is common.

You are correct about not using them for engine building, such as checking the crank, or other detail measurments. But they are great to use to let you know if you are in the ball park.


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