I'll try to make a long story short. I have my gsr motor built by a ex-friends shop. They let their machine shop build the short block. They said they have to deck the block and shave the head. They also said the shaved the pistons to bring the compression back down. Well the oil pump failed and spun 3 rod bearings. Well I got new rods and a new crank. I'm going to rebuild it myself.

I'm trying to figure out what the compression ratio is. When I did a wet compression test it was 170 170 170 170. The pistons are suppose to be 9.0. I'm really just trying ti figure out what head gasket I need to go with.

Please post what your piston comp. is and what your compression test results are. Trying to get an idea of what my compression will be once I get it back together. Heres a pic of the piston to deck clearances.

 

Last time I did mine I was around 175-185. I have 8.9 compression weisco pistons. Having about 170 across the board is not bad at all

 

Thanks alot man. That makes me feel alot better.

 

I am around 8.6-8.7 and I was reading high 180's..... also with Wiseco's and an 81.5mm Bore.

The numbers are supposed to go up a little once the motor is broken in if everything seats correctly.

 

So if I was around 170 its prolly around 8.4?

 

um, your block guard needs be lower in the sleeves...being ontop like that will cause heating issues later down the line.

 

Thats how the shop did it. We drove it in the summer on almost 100 degree weather and had not problems at all. I'm trying to figure out if I should run a thinner then stock head gasket and try to get the comp up some. But then I'm dealing with the piston to valve issues.

 

how long did you drive it or how many miles until it spun the bearing?

 

It lasted around 1800 miles and it spun a bearing on the dyno. So it was shut off and put on the trailer. The cylinder walls are fine as the rest of the block. Got the new crank the other day and the new rods will be here next week. Shouldn't the pistons be closer to the deck?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BoostedEgHatchFl &raquo;</TD></TR><TR><TD CLASS="quote">So if I was around 170 its prolly around 8.4?</TD></TR></TABLE>

If you know what has been cut off your head and/or block if that has ever been done then you can use one of the many online comp calculators and get an accurate comp ratio instead of guessing based on a comp test.

It looks like your pistons are at least .015 in the hole, and if you have low comp dished pistons if my memory is correct that equals a pretty low compression with a stock HG.

For comparison my pistons are .016 out of the hole with a dished piston, I have had a few cuts on the head too and I run a .065 Cometic which leaves me below 9.0:1, but the car pulls just fine like that, my boost comes in pretty quick.

 

I have no idea whats been cut. The shop told me 8 thousands off the block. But I don't know that seems like alot. I could measure everything. Theres the deck measure point on the deck of the block, the biggest feeler gauge I could get in there was .016. But I don't know what it is suppose to be stock. The I could measure the pistons and call JE and get the specs.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96 GSR-T &raquo;</TD></TR><TR><TD CLASS="quote">

It looks like your pistons are at least .015 in the hole, and if you have low comp dished pistons if my memory is correct that equals a pretty low compression with a stock HG.</TD></TR></TABLE>

It was a cometic gasket. Which the only on listed on there site is .030 which I was told was stock think ness

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by methos713 &raquo;</TD></TR><TR><TD CLASS="quote">um, your block guard needs be lower in the sleeves...being ontop like that will cause heating issues later down the line.</TD></TR></TABLE>

Can you clarify to me how will this cause heating issues?

 

I have no idea man, I never has any issues.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yakuza &raquo;</TD></TR><TR><TD CLASS="quote">

Can you clarify to me how will this cause heating issues?</TD></TR></TABLE>

You won't literally see the temp gauge running hotter all the time.. Having the block guard at the highest point of the deck (also the area which all the combustion events are happening), it makes the engine run hot internally and more prone to detonation and knock.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yakuza &raquo;</TD></TR><TR><TD CLASS="quote">

Can you clarify to me how will this cause heating issues?</TD></TR></TABLE>

https://honda-tech.com/zerothread/2363747

Read the whole first page.

https://honda-tech.com/zerothread?id=2054965

https://honda-tech.com/zerothread?id=1905088

I don't know how the machine shop installed your guard, but if it was me, I have it check...since your saying they f-up on the build.

 

The block guard was installed b4 it ever went to the machine shop.

 

Just measure my HG and its a .030. What would be the next thinnest? So I could raise the comp. some.

 

bump

 

Cometic's thinnest gasket is .030, Honda oem is .026. You can use Toda/spoon/mugen gaskets to raise it even more if you need.

 

Do you think an OEM head gasket, would raise it up too much?

 

brand new broken in 81.5mm gsr with 9.0:1 compression 190psi accross the board as far as I recall. Stock headgasket. As long as your numbers are all about the same you will be fine. I never heard of anybody shaving the pistons.

 

I looked up the mugen head gasket but they don't make it in a 81.5. I'm going to do a cc test on the head and block and go from there. In the pic the pistons should be a little high since the bearings were spun and it was the top ones.

 

I'm pretty sure you can run stock bore gasket even if it's a mugen one. Besides I wouldn't try to calculate your compression doing a compression check. It can go up with motor being broken in more, or it could be off because of the gauge or because you didn't open the throttle. Also like other people said the block guard has to be a 1/4" in the block, but it's too late to do that now because the motor has to be bored and honed with it installed.

 

I can prolly tap it down little by little and get it down. Its gotta go back to the machine shop anyways to get rehoned since I'm getting new piston rings. I was just trying to get a rough idea of what the compression was but that compression test results. I want as close too 9.0 or higher I can get.