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2jzge 6spd
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133 Posts
Discussion Starter #1
The machine shop screwed up milling the deck. They took .006 off the deck and scored deeper lines than normal on there first pass. Its affected a 1/4 of the decking surface. 3/4 is normal an smooth with the .006 taken off other parts have grooves deeper than the smooth parts.

There are deep enough grooves your finger nail can feel it/slightly fall in an out of it. sad thing is some of these grooves run right to the piston hole.

If I were to leave this and run it I would just be asking for blown head gasket.

I am having them mill it again until the groves go away, might be another .006 or more.

How much is too much Milling?

**Question is how much will this affect my compression ratio? 8.5:1 pistions, TT head gasket 1.2mm, NA Head.

**Will I still be able to run 25 to 28 PSI safely on this motor with stock TT head gasket, TT pistons and the appropriate supporting parts/mods?
 

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2jzge 6spd
Joined
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133 Posts
Discussion Starter #3
NA block had 100k on it rebuilding fresh block with TT pistions, new bearings seals etc.

I had it honed and the deck was too nasty to get good seal on next head gasket even with hot tanking it.
 

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Banned
Joined
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566 Posts
True that, get a .091 gasket, will cover the difference and then some.

I can get custom thickness cometic MLS gaskets for the NA for right cheap, pm me.

Josh
 

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2jzge 6spd
Joined
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133 Posts
Discussion Starter #6
I went a head and got the TT head gasket since I was getting other things from toyota.

I picked up the block again after the first time was a really rough cut and some scored mistake grooves. This time they sent it off to another person that has a the $80,000 Fly Cut Machine and they said that they took off less than .003. I'll never really know. It did come back smooth like from Toyota. No lines or grooves now.

.006 first cut
.003 or so second cut

Puts me at .01 8.51:1 Shouldn't limit my ability to boost 25lbs right?


I just wasn't going to boost 25lbs on finger nail grooves that go right up to the cylinder wall.

Its pretty smooth now, some people say that too smooth can make the headgasket move around and because its too smooth it doesn't have anything for the gasket to bite to like grooves.

It it recommended to sand paper the deck with a fine grit and flat block to give it some bite or it shouldn't be a problem?????

I just wasn't going to boost 25lbs on finger nail grooves that go right up to the cylinder wall.
 

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Lexotic Garage
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1,470 Posts
I run a 2000 grit emory pad across my block deck on every rebuild. it helps take off leftover black HG goo, and it clean up the deck nicely.
 

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Cheifbootknocka
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1,944 Posts
Since they messed up I would ask that they either buy you the thicker cometic gasket or the difference between the regular thickness and the thicker, if there is one.

The machine shop screwed up milling the deck. They took .006 off the deck and scored deeper lines than normal on there first pass. Its affected a 1/4 of the decking surface. 3/4 is normal an smooth with the .006 taken off other parts have grooves deeper than the smooth parts.

There are deep enough grooves your finger nail can feel it/slightly fall in an out of it. sad thing is some of these grooves run right to the piston hole.

If I were to leave this and run it I would just be asking for blown head gasket.

I am having them mill it again until the groves go away, might be another .006 or more.

How much is too much Milling?

**Question is how much will this affect my compression ratio? 8.5:1 pistions, TT head gasket 1.2mm, NA Head.

**Will I still be able to run 25 to 28 PSI safely on this motor with stock TT head gasket, TT pistons and the appropriate supporting parts/mods?
 
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