1.2mm mhg

[black89t]

can you run a 1.2mm mhg 7m on the stock ecu? i know hks sells them and people have ran them. so does it ruin the timing? or what?

couldn't seem to find anything about it. i remember reading wesbeech's build where he shaved the hell out of the head with a 1.2mm saying his compression way up there running fine. i can't remember if he was on the stock ecu. i'm more worried about timing though. and yeah the stock compression is ideal but what about all those motor that get the 1.2mm or 1.4mm with .025" total shaved?

any thoughts or knowledge on the subject would be great.

 

[suprahero]

1.2mm hg is fine. Did you have your head and block shaved?

 

[kamikazemkiii]

If your looking for boost i deff wouldnt use a 1.2mm hg, its already thinner than stock

 

[suprahero]

Sizing a 7MGTE Headgasket: In some cases, the engine will require machining due to warping on the head or block. Find out how much needs to be trimmed in thosandths of an inch, and convert it to millimeters (40 thousanths of an inch is equal to one 1mm). You need to compensate for this amount with the gasket width -- a stock gasket is 1.0mm. Convert the total amount that was trimmed from your block and head to millimeters and add it to 1mm and you'll have the gasket size you need. Try to stay as close to this number, since it is crucial in order to run the proper compression. If you don't understand this, ask your machine shop or engine builder and they should be able to provide this numner.

This was taken from this link here.
http://www.jscspeed.com/mk3/engine/headgaskets.htm

 

[black89t]

suprahero i understand that. its just i'm looking at this motor that has already been built. the guy selling it says it run great, but i'm pretty sure he has an AEM. i'm just wondering if i should buy this motor or not. i don't want the 1.2mm hg to be a problem. now you see my situation.

thanks for the responses

 

[Zumtizzle]

As long as it's under 8.7:1 and you know what youu're doing you'll be fine.

 

[Shaz]

can you run a 1.2mm mhg 7m on the stock ecu? i know hks sells them and people have ran them. so does it ruin the timing? or what?

couldn't seem to find anything about it. i remember reading wesbeech's build where he shaved the hell out of the head with a 1.2mm saying his compression way up there running fine. i can't remember if he was on the stock ecu. i'm more worried about timing though. and yeah the stock compression is ideal but what about all those motor that get the 1.2mm or 1.4mm with .025" total shaved?

any thoughts or knowledge on the subject would be great.

Did everyone miss this and forget to mention that the two are pretty much unrelated?

 

[Kai]

Hang on, i was under the impression the stocker was 1.37mm compressed?

 

[7M-KDL]

Hang on, i was under the impression the stocker was 1.37mm compressed?

i thought so too...

 

[BrandonW]

http://www.supramania.com/forums/showpost.php?p=1328009&postcount=1

stock hg is 1.37mm compressed

 

[Tanya]

stock HGs on JZ engines are thinner I believe.


suprahero is just trying to confuse you all

 

[lewis15498]

Hang on, i was under the impression the stocker was 1.37mm compressed?

Yes, I distinctly recall Ian saying this.

 

[gaboonviper85]

Suprahero fails 7m:-(

 

[suprajztwenty]

i was told the engine in mine was rebuilt about 20-30k ago with the 1.2 in it and arp's
im going to do a retorque soon but what do you guys think, new gasket to be safe...my goal is 400 to the wheels, how much should i worry with the 1.2, probly good till 300 atleast.

i understand the head is going to flex but i dont see how that .1mm is going to mean the life and death of the project. can i get more details as to why the 1.2 is a bad idea?

 

[gaboonviper85]

Cause it reduces cylinder volume which increases compression which in turn reduces the detionation point...high compression+boost=bad news unless one is very very careful and has equipment to raise the det point....such as meth/water injection, race fuel, engine management, etc...

Low compression is a turbo cars best friend!

 

[Hmong_1G]

I'm in this boat right now. My rebuild consisted of a block and head got shaved (machine didn't supply info about HOW MUCH TAKEN OFF). On top of that I'm running the 1.4 cometic MHG. After some careful readings I find out that the Probe .040 pistons have a 8.6:1 compression. I'm still unable to find out how much they've taken off as the person who did the shavings is on medical leave and no records were kept. <--- ( WEIRD). Taken all into aspect that my head was warped and the block was shaved plus the probe pistons.... numbers should be some where around 8.7:1 to 8.9:1. This only a guesstimate.

PS. I'm never ever gonna use this shop ever again.

 

[gaboonviper85]

I measured my head myself after it was decked.... 6" dial caliper cost about $30...

The block you just take it back to them and tell them to measure it...the Toyota specs are sticky in the headgasket thread by IJ

it's not rocket science people...

I measured a locals block and head for him a little bit ago so he could order his headgasket....he was smart and purchased his gasket last such as myself...perfect example of people building engines without doing prior research:nono:

 

[Shima]

i ran a 1.2 hks on mine and it worked a treat just depends on what mods your wanting done. big power i wouldnt recommend using it though.

-shima

 

[7M-KDL]

dont want to hi-jack(completely) but what do you think about a 1.4mm. still think detonation will be a problem at higher boost levels. btw, i plan to have meth injection when i get to that point, i just had my motor built so i have to break it in for a lil while

 

[jdub]

A 1.4mm MHG is basically stock HG thickness. With a good tune (and not going boost crazy) that thickness is fine.