I've heard of rust problems before with crate motors.  Are you sure you didn't 
have rust to begin with?
 
-Jon



--- On Wed, 10/7/09, Blake Thompson <[email protected]> wrote:


From: Blake Thompson <[email protected]>
Subject: Re: 2008 Crate head failure
To: "<[email protected]> <[email protected]>" 
<[email protected]>
Date: Wednesday, October 7, 2009, 12:37 PM


I spoke with Stewart today and they said EVERY valve had rust on it.  I'm 
wondering if I got bad gas that was full of water?


On Mon, Oct 5, 2009 at 3:52 PM, Jason C <[email protected]> wrote:





Lack of lubrication in the valve guides? 






 
 
 
 
Larry Alster
 
91 Miata  White Knight
92 Miata  Silver Bullet
92 Miata  Honey B
04 MSM MX-5 Whooosh
06 WRX STi Subie
 

From: [email protected] 
[mailto:[email protected]] On Behalf Of Blake Thompson
Sent: Monday, October 05, 2009 1:19 PM
To: <[email protected]> <[email protected]>
Subject: 2008 Crate head failure
 

wtf did i do this thing after only 10 races?  Any ideas?

 

Cylinder 4 - exhaust valves unseated

http://btdtracing.com/gallery/d/10706-2/head2.jpg


Cylinder 1 - exhaust valve extended or bent:

http://btdtracing.com/gallery/d/10703-2/head.jpg

 

Labor day weekend (a month ago, now) I raced.  The car performed well, I didn't 
notice any power issues.  I brought the car home and parked it.  About two 
weeks ago I started and it sounded like shit, like it was running on two 
cylinders.  I assumed the coil had GTSd.  I didn't bother with it until this 
weekend when it wouldn't start at all.  I started with the CAS then the Coil 
then the ignitor before I got it running again, but she still ran like shit. 

So I started a leak down.  Cyl 1 - 30%, Cyl 4 - 100% (yes, on the compression 
stroke).  Attached is a picture of the exhaust valve in cylinder 1.  Cylinder 4 
it looks like both valves are out about 1/16" or more.  Cylinder 1 is at least 
3/16"

So the head is off my car, on its way to Gasoline alley.  But my question is, 
what did I do to cause this?  I've not missed a shift and I dont rev past the 
limiter.  The motor is a Mazda crate which I bought in May of last year.  It 
has maybe 10 races on it.  I run Royal Purple XPR 10w30 (i think, off the top 
of my head) in the car and religiously change the filter every race and oil 
every 2.

I noticed my header was cracked as well, i donno if this was the cause or the 
result of bad valves.

The valve springs look fine and dandy, all operating well, the cams move 
smoothly.  The valve, however, is very stiff and I couldn't move it with my 
bare (bear!) hand, nor did it move when i rotated the cam.

There is a picture attached of cyl 4 here, the ex valves again are the ones in 
question, they don't seem to be seated properly.  I have a feeling one of the 
cylinders has been screwed for a while

To answer your other questions, the AFM is untuned and I thought I was using a 
pretty conservative timing.  I ran 87 for practice and qual at the mile and 
then switched to 110 from a  nearby pump for the race.  I typically run 
whatever the track gas is but that wasn't available at the mile.

 

BTW, this is a 90 spec miata with a 1.6L crate bought from mazda in May of 
2008.  It's got maybe 1000 miles on it, 400 of which were break in miles on the 
interstate :p

 

-Blake

SM#97

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-- 
http://BTDTRacing.com -  World Champion Miata Parts Sales.  Now in HD!

Our ebay store:  http://stores.ebay.com/btdtracing-36
or Subscribe to our active listings page:
http://esssl.ebay.com/GetListings/btdtracing36?fmt=g

This is our decision, to live fast and die young.
We've got the vision, now let's have some fun.

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