Checking squish clearance

[D-1]

I'm checking the squish on a 80 cube evo. I normally use plasticine or solder on twin cams which works great, but I'm finding on the evo with the single side squish band it's a bit inconsistent.

With the solder on the one side, the piston must rock to that side and the clearance is 0.050" with a 0.036" gasket. But if I have a straight edge along the top of the barrel (no gasket) and rock the piston past TDC, there is basically no clearance.

Bottom end has been done and wrist pin clearance is good, I think my testing method is flawed? On a TC, I think the solder placed on both sides of the combustion chamber balance out, but the single side evo not so much. How do you all do it?

[Ohio HD]

Best way is have the rings installed. I use clay or a dial indicator. Dial indicator works best.   

[attach=0]

[D-1]

So you bolt the bracket down and zero it on the barrel, then swing it over to the flat section of the piston? Sounds good, I'll make one tomorrow, thanks.

[Ohio HD]

Close, I use a known thickness flat bar across the cylinder bore. Mine happens to be 0.080" thick. I set the dial indicator to 0.080" while it rests on the bar stock. Then when the bar stock is removed, the virtual 0.000" depth is calculated from the actual piston height or depth. +/-

[D-1]

Roger, thanks.

[thumper 823]

The squish as you probably know is one of the biggest factors in good performance.
I run 0.30  thou on mine.
I checked it with mock up and clay.
I did not like that,  and the soft solder is no longer available.
SO, I ended using body filler as in drops around the edge.
Its much more EZ to measure and fool proof if there was inconsistency in machining.

[FSG]

Best way is have the rings installed.  ........   

  or put a wrap of masking/gaffer tape around the upper part of the piston

[D-1]

Made this today and it works great. Put 2 wraps of electrical tape around the ring lands so it was a neat fit in the bore. At TDC the indicator read 0.001" out of the hole, and trying to rock the piston side to side didnt have any effect on it, so im pretty happy its accurate.

Thanks for the help everyone. 

[Ohio HD]

Nice work.   

[thumper 823]

what number are you trying to achieve? (squish clearance )

[D-1]

Was aiming for zero with a 0.030" gasket, but it's already 0.001 out of the hole on the front and I haven't checked the rear yet. Depending on what the rear is, I may put the pistons 5 thou hi and use a 36 or 40 thou gasket.

[thumper 823]

ZERO ?
WOW
And everyone has always said my thirty thou was way too tight.
Next point-
I have always been under the impression the squish (a good one )
on the tight side,  is was gave the lift off  (OK push dwn ) .
So, no squish is what you are shooting for ?

[D-1]

The piston at zero deck height and a 0.030" gasket giving 0.030" squish clearance

[Deye76]

"0.030" squish clearance"

Make sure you warm it up before flogging it.

[thumper 823]

Now I got ya.
I was a little worried about 30 thou.
However, it has worked very well for me!
That and a 9 lb ring pack !

[koko3052]

Have 27 thou on my TC 95" & 70K kms on it now, never had an issue.

[thumper 823]

I guess I  now have a new goal line.
Is it double plugged?
Or ?

[Burnout]

Have 27 thou on my TC 95" & 70K kms on it now, never had an issue.

A TC has a shorter stroke, shorter cylinder less growth.
You can't compare a soulless-short-stroke-small-valve motor to a BT EVO.

[Deye76]

"You can't compare a soulless"..........

What Knuckle owners said about Pans, & Pan owners about Shovels, and Shovel owners about Evo's, and Evo about TC and TC about M8, and the beat goes on. 

[thumper 823]

I have Axtell Cast iron cylinders on my EVO with the o3o squish .
No base gasket just Yamabond.
They work purrfect!
The iron is much more stable than the aluminum.
If I had to use aluminum cylinders I would have them cut for an "O" ring on the bottoms.

[Hillside Motorcycle]

Axtell cyls on our racer.
No gasket on base or head.
Mini fire-lip interference crush.
.040" lip, .038" c/bore in the head.

[thumper 823]

I now have 0.026 and have run it a total of a couple of minutes with no obnoxious noises.
This remains to be seen if it holds or not.
It has 0.026 over a  3/4  to a one-inch area outside (of course) radius one the long side of the angle tops  [attach=0] 

[thumper 823]

Try this one more time

[attach=0,msg1300798]

[Burnout]

That looks like it uses a shovelhead piston?

[thumper 823]

Axtell angle tops with their redesigned combustion chamber.

[thumper 823]

angle tops

The best pics I have as of right now-
In this pick I am fusing with the oil control spacer attempting to get less drag.
I made a special tool to get a nice slow push dwn through on an electric scale.
The tool is a snowmobile clutch tool, but seriously a couple of sticks of wood bolted to gather would do the same thing.
I got front piston dwn to 11 lbs and the rear to 10 lbs.!
She will either be an oi blower or a real goer.
The weird part after the cylinders was installed- pistons,  rings and all
it took less the 5lbs to spin the engine over .
I thought the drag would be cumulative  (times two)
That is a lot less than a stocker which can be as high as 30 and more!

[attach=0,msg1300805]

[attach=1,msg1300805]

[thumper 823]

 [attach=0]  [attach=1]

[thumper 823]

I use dental plastic as it will it mar the ceramic coatings on the pistons and the top of the combustion chamber



[attach=0]  [attach=1]

[Hillside Motorcycle]

How is the helicopter coming along?

[thumper 823]

 [attach=0,msg1300867] .


It is all almost.
need one more roof built here (wood blades)
And its dwn to the valve train on the other engine.
It was all cockeyed and imposable   to get centered
the enginamaneer went with 1/2 longer rods
a redo in the oiling system so oil to the top main bng.
line bore
and a bunch of other boring things..

[thumper 823]

Finaly did the dyno !
1994 EVO, std stroke, 80 inch (20 over)
Hill side gets the thank you for the final volly and tune   [attach=0,msg1359921]

[Adam76]

Finaly did the dyno !
1994 EVO, std stroke, 80 inch (20 over)
Hill side gets the thank you for the final volly and tune   [attach=0,msg1359921]

Wow, nice result thumper.  👍
What was done with the voes?

[Adam76]

I'm currently aiming for .030" myself, with zero deck and .030 HG..... From everything everyone's told me so far, this is ideal for performance and burn efficiency as far as safe before running into possible detonation problems?? 
I've been aiming for .030 -  0.032 from the beginning.... Should have it all together soon -- but now I'm thinking I should be checking piston to valve clearance? I didn't think it would be a problem worth checking for with my build?
Thanks

[kd]

 

[RTMike]

.030 is a little tight..035-.040 is what I shoot for

[kd]

.040 is oem 

[turboprop]

I'm currently aiming for .030" myself, with zero deck and .030 HG..... From everything everyone's told me so far, this is ideal for performance and burn efficiency as far as safe before running into possible detonation problems?? 
I've been aiming for .030 -  0.032 from the beginning.... Should have it all together soon -- but now I'm thinking I should be checking piston to valve clearance? I didn't think it would be a problem worth checking for with my build?
Thanks

If there is any doubt then there is no doubt. Unless you just enjoy not sleeping and having endless  online discussions based on conjecture and what others are simply repeating as fact. Check that piston to valve clearance. The other person that sleeps in you bed will thank you.

[kd]

   You'll find it interesting to do and it will be a huge stress relief knowing as turboprop has pointed out.

[Adam76]

I'm currently aiming for .030" myself, with zero deck and .030 HG..... From everything everyone's told me so far, this is ideal for performance and burn efficiency as far as safe before running into possible detonation problems?? 
I've been aiming for .030 -  0.032 from the beginning.... Should have it all together soon -- but now I'm thinking I should be checking piston to valve clearance? I didn't think it would be a problem worth checking for with my build?
Thanks

If there is any doubt then there is no doubt. Unless you just enjoy not sleeping and having endless  online discussions based on conjecture and what others are simply repeating as fact. Check that piston to valve clearance.The other person that sleeps in you bed will thank you.

Ok, thanks. I guess I just made an assumption and I was wrong..  Never done any of this before, so everything is a learning curve. Appreciate the advice.
I don't  sleep at night much, but that's another story.

[Adam76]

  You'll find it interesting to do and it will be a huge stress relief knowing as turboprop has pointed out.

Yep,  will do. And it will be an interesting exercise to do and learn for this and future builds. 
Cheers

[Adam76]

Close, I use a known thickness flat bar across the cylinder bore. Mine happens to be 0.080" thick. I set the dial indicator to 0.080" while it rests on the bar stock. Then when the bar stock is removed, the virtual 0.000" depth is calculated from the actual piston height or depth. +/-

Ohio, is it still an ok method to set up the dial indicator and zero it out using the top of the barrel surface like D-1 mentioned?  I was going to use this method to check my deck height once my cylinders go back on. Kind of like the picture you posted.
Thanks.

[Ohio HD]

Close, I use a known thickness flat bar across the cylinder bore. Mine happens to be 0.080" thick. I set the dial indicator to 0.080" while it rests on the bar stock. Then when the bar stock is removed, the virtual 0.000" depth is calculated from the actual piston height or depth. +/-

Ohio, is it still an ok method to set up the dial indicator and zero it out using the top of the barrel surface like D-1 mentioned?  I was going to use this method to check my deck height once my cylinders go back on. Kind of like the picture you posted.
Thanks.

The reason I do it as I mentioned is I have a fixed indicator bracket for use on HD motors. Once bolted to the cylinder I don't want to move it. This is why I do it as I explained. Moving the indicator base once zeroed might be accurate, it might not be. It's just not good machining practices to move your point of reference. 

[Adam76]

Close, I use a known thickness flat bar across the cylinder bore. Mine happens to be 0.080" thick. I set the dial indicator to 0.080" while it rests on the bar stock. Then when the bar stock is removed, the virtual 0.000" depth is calculated from the actual piston height or depth. +/-

Ohio, is it still an ok method to set up the dial indicator and zero it out using the top of the barrel surface like D-1 mentioned?  I was going to use this method to check my deck height once my cylinders go back on. Kind of like the picture you posted.
Thanks.

The reason I do it as I mentioned is I have a fixed indicator bracket for use on HD motors. Once bolted to the cylinder I don't want to move it. This is why I do it as I explained. Moving the indicator base once zeroed might be accurate, it might not be. It's just not good machining practices to move your point of reference.

Ok thanks, that makes sense.

I was going to use a traditional deck bridge like this one.

[thumper 823]

A tight Squish is part of what is needed to combat spark knock with High comp, and low octain gas .
I am at an honest .026 and have about a 1000 miles on it.
(Plus Scott @ Hillside said it would work.)
This is Dual plugged-  225  front and 235 rear CCP, @ 65F -OAT,    1700 feet above seal level.   W8 Cam
Keep in mind most pistons will not give a constant number through the outside radius (Uness they have been chucked up)
I have measured the leak dwn @TDC (minus a couple of deg)  and it is near zero.
I am not exagerating.
Now keep in mind I have nodular cylinders and all the graphs I have read say Nodular does not have near the growth that AL jugs do.
You will have to do your own math to figure out what you get with al @ operating temps.
A std Evo head comes with a lot of area to be removed as a virgin head can have .050 to .070 to get it to pefomance area. AFAIK.

Yes STD  VOS hooked up.

[Ohio HD]

Close, I use a known thickness flat bar across the cylinder bore. Mine happens to be 0.080" thick. I set the dial indicator to 0.080" while it rests on the bar stock. Then when the bar stock is removed, the virtual 0.000" depth is calculated from the actual piston height or depth. +/-

Ohio, is it still an ok method to set up the dial indicator and zero it out using the top of the barrel surface like D-1 mentioned?  I was going to use this method to check my deck height once my cylinders go back on. Kind of like the picture you posted.
Thanks.

The reason I do it as I mentioned is I have a fixed indicator bracket for use on HD motors. Once bolted to the cylinder I don't want to move it. This is why I do it as I explained. Moving the indicator base once zeroed might be accurate, it might not be. It's just not good machining practices to move your point of reference.

Ok thanks, that makes sense.

I was going to use a traditional deck bridge like this one.

That's fine to use. Put it in place over the center of the piston, use a precision thickness flat stock, set the indicator to the flat stock thickness, not zero, Then when the flat stock is pulled out, you have a zeroed indicator for over the bore.

I prefer a bolted down or magnetic base indicator so I can slowly roll the motor back and forth to make sure I have a good reading as to what the piston measures at TDC.

[kd]

Close, I use a known thickness flat bar across the cylinder bore. Mine happens to be 0.080" thick. I set the dial indicator to 0.080" while it rests on the bar stock. Then when the bar stock is removed, the virtual 0.000" depth is calculated from the actual piston height or depth. +/-

Ohio, is it still an ok method to set up the dial indicator and zero it out using the top of the barrel surface like D-1 mentioned?  I was going to use this method to check my deck height once my cylinders go back on. Kind of like the picture you posted.
Thanks.

The reason I do it as I mentioned is I have a fixed indicator bracket for use on HD motors. Once bolted to the cylinder I don't want to move it. This is why I do it as I explained. Moving the indicator base once zeroed might be accurate, it might not be. It's just not good machining practices to move your point of reference.

Ok thanks, that makes sense.

I was going to use a traditional deck bridge like this one.

That's fine to use. Put it in place over the center of the piston, use a precision thickness flat stock, set the indicator to the flat stock thickness, not zero, Then when the flat stock is pulled out, you have a zeroed indicator for over the bore.

I prefer a bolted down or magnetic base indicator so I can slowly roll the motor back and forth to make sure I have a good reading as to what the piston measures at TDC.

Very important.  Measurements at each side and above the pin can vary when the piston rocks in the bore.

[Adam76]

Very important.  Measurements at each side and above the pin can vary when the piston rocks in the bore.

Thanks kd, my piston being a KB forged with a small dome (9.5 pistons) don't have many areas on the actual top surface of the piston to measure from? I'm only really able to use one section on the right hand side of the  piston top that isn't affected by the dome or the valve reliefs?

[thumper 823]

Your squish is the closest area to the head,   no matter where it is.
AFAIK you want it as tight as posable, and there is endless theory on it.
Even maching groves to the other side.
The importatnat part is close, but not so close they kiss each other.

[kd]

What year and type cylinder head are you using?

[Adam76]

What year and type cylinder head are you using?

If asking me?  I'm using 1996 softail motor with stock heads that now have 0.010" off them just back from the machine shop. Because it wasn't a high performance precision build, I didn't cc the heads, so I have no idea where they're at.... but they looked virgin to me when I pulled then off. Then again, how would I know?
Cheers