Piston Height Question

[HotFoot]

Is This the right way to check for squish hieght of 30 thou ???

 

[Jay]

You might want to make up some sleeves to go over the four corner studs ( And really fine looking studs, I might add) and run nuts down to make sure the block is firmly seated so you won't get a bogus measurement. Then I would check it with a depth mic.

Jay

 

[HotFoot]

So Jay
I am measuring at the right place
and just looking for a 30 thou clearance
from the deck height to the top of the piston

Next question
right now I have the 80 spacer plate on
If I add the gasket do I put It on first and
then the plate or vice versa

 

[OB_John Noonan]

The way you are doing it is incorrect however may yield close enough results, the pistons you are using appear to be part number 213918 from je and are a standard bore Hayabusa 81mm (3.189") bore size.

The pistons you have call out for .004" of piston to cylinder clearance which ina properly tuned engine is 25% more clearance than you need.

You need to do like APE MAN said and tighten down the block to get the correct piston to head clearance however you also need to check your V-P clearance (Valve to piston) if you have a stock head and cams with less .395" of lift or less you should be fine.

You may also want to measure the exhaust and intake clearances and average them however remember the exhaust side will grow/expand more due to heat so watch your clearances.
The proper deck height is .036" street to .041" race however depending on the rods, RPM, racing type and bearing clearances it will vary.

If I am correct on guessing the part number of your pistons then yes you will need to run a .080" thick base spacer from Cometic (also available from APE) as a minimum and also perhaps a .005" thick base shim, it is a Copper base gaskets and at times when building an engine they come in handy due to machined cylinders (after a repair or decking) or when you need to have more piston to valve clearance or piston to head clearance.

I have built dozens of these turbo Busa engines so if you need more info please PM or email me at q u i c k t u r b o @ a o l . c o m <-----no spaces.

John Noonan.

PS, I also use the APE internal engine components like valve springs and clutch springs, adjustable cam sprockets, a piston stop for dialing in your cams, HD nuts and HD engine studs, HD main studs and Titanium valve retainers.

These APE parts have been tested and proven at 259 and 260 mph by two different riders.

J

 

[GoldenChild]

The way you are doing it is incorrect however may yield close enough results, the pistons you are using appear to be part number 213918 from je and are a standard bore Hayabusa 81mm (3.189") bore size.

The pistons you have call out for .004" of piston to cylinder clearance which ina properly tuned engine is 25% more clearance than you need.

You need to do like APE MAN said and tighten down the block to get the correct piston to head clearance however you also need to check your V-P clearance (Valve to piston) if you have a stock head and cams with less .395" of lift or less you should be fine.

You may also want to measure the exhaust and intake clearances and average them however remember the exhaust side will grow/expand more due to heat so watch your clearances.
The proper deck height is .036" street to .041" race however depending on the rods, RPM, racing type and bearing clearances it will vary.

If I am correct on guessing the part number of your pistons then yes you will need to run a .080" thick base spacer from Cometic (also available from APE) as a minimum and also perhaps a .005" thick base shim, it is a Copper base gaskets and at times when building an engine they come in handy due to machined cylinders (after a repair or decking) or when you need to have more piston to valve clearance or piston to head clearance.

I have built dozens of these turbo Busa engines so if you need more info please PM or email me at q u i c k t u r b o @ a o l . c o m <-----no spaces.

John Noonan.

PS, I also use the APE internal engine components like valve springs and clutch springs, adjustable cam sprockets, a piston stop for dialing in your cams, HD nuts and HD engine studs, HD main studs and Titanium valve retainers.

These APE parts have been tested and proven at 259 and 260 mph by two different riders.

J

 

[OB_John Noonan]

Kevin,

Good talking with you today, should you need any further information please call me.

John

 

[HotFoot]

Thanks for clearing up things for John

 

[Allan McD]

The way you are doing it is incorrect however may yield close enough results, the pistons you are using appear to be part number 213918 from je and are a standard bore Hayabusa 81mm (3.189") bore size.

The pistons you have call out for .004" of piston to cylinder clearance which ina properly tuned engine is 25% more clearance than you need.

You need to do like APE MAN said and tighten down the block to get the correct piston to head clearance however you also need to check your V-P clearance (Valve to piston) if you have a stock head and cams with less .395" of lift or less you should be fine.

You may also want to measure the exhaust and intake clearances and average them however remember the exhaust side will grow/expand more due to heat so watch your clearances.
The proper deck height is .036" street to .041" race however depending on the rods, RPM, racing type and bearing clearances it will vary.

If I am correct on guessing the part number of your pistons then yes you will need to run a .080" thick base spacer from Cometic (also available from APE) as a minimum and also perhaps a .005" thick base shim, it is a Copper base gaskets and at times when building an engine they come in handy due to machined cylinders (after a repair or decking) or when you need to have more piston to valve clearance or piston to head clearance.

I have built dozens of these turbo Busa engines so if you need more info please PM or email me at q u i c k t u r b o @ a o l . c o m <-----no spaces.

John Noonan.

PS, I also use the APE internal engine components like valve springs and clutch springs, adjustable cam sprockets, a piston stop for dialing in your cams, HD nuts and HD engine studs, HD main studs and Titanium valve retainers.

These APE parts have been tested and proven at 259 and 260 mph by two different riders.

J

Why do you have to run a 2mm spacer with these pistons ?
Would a 1mm be ok if running methanol ?

Allan

 

[Hayabusa Wannabe]

Welcome to the forum @Allan McD.