Deck height questions???

Jeff Alton · 04-23-2006, 08:43 PM

Okay, so I mock up the motor tonight to get a rough idea on the deck height. I have never used the solder method before, only the caliper depth method. Soooooo, I try both and get very different numbers!! WTF. Here are some pics, tell me if I have the solder in the correct spots or not. I even checked both sides of the case and used two different cylinders on both sides to double check my work. So which is the accurate number?? Using the solder, I got .050 inch. Using the depth caliper I got .022......
This was done with a spare set of heads, not the ones that will be on the motor and NO base gaskets were used.

What should I think here??

Here are the pics

Mock up

Solder

Solder caliper measurement

Depth caliper measurement

Cheers

Mike Juzenas · 04-23-2006, 10:13 PM

Hi Jeff,

Some ideas..

Its hard to tell from your pictures....did the solder go right to the edge of the piston? From what I can see it looks like the solder is on the crown of the piston but not in the deck area.....or is it the angle? Then I did mine the solder gets squeezed into a tapered shape and you have to be carefull to make sure you are measuring the right spot.

Is there any space on the heads that you are not allowing for when you use the depth guage?

Cheers,

Mike

JeremyD · JeremyD's Garage

I didn;t think you could use caliper dept method with 3.2 - and like Mike said - I think it has to be to the lip of the piston... so = with .25 base gasket you ** might ** barely have enough room. I'm guessing from your measurements and crown these are high comp pistons?

Jeff Alton · 04-24-2006, 04:33 PM

JE 10.5 to one pistons. I have both .25 and .50 gaskets here, so that is no problem, and lots of them too!! The JE as you know has a small flat section before the dome starts, and that is where I measured using the caliper.

Cheers

Mike Juzenas · 04-24-2006, 04:47 PM

Hi Jeff,

Are you using the magic bronze tool or something else?

Cheers,

Mike

Jeff Alton · 04-24-2006, 05:08 PM

The magic tool won't work, I have had some success on the bench using the two screwdriver method......... I even modded the tool abit, but all to no avail!

Cheers

stevepaa · 04-25-2006, 09:05 AM

Be sure to get the solder right up to the cylinder wall for your measurement. I did all 4 quadrants.

Jeff Alton · 04-25-2006, 02:15 PM

Hmmm, I guess I will give that a try, kinda tough though as the piston has a very small flat surface around the outside.

Cheers

bbh03 · 04-25-2006, 04:27 PM

I was able to use the caliper method with repeatable results on my JE 9.5:1s. The flat lip allows this if your caliper is narrow enough. The lip allows the 98mm piston to clear the 95mm head so it should be about 1.5mm wide. I cleared the method with Henry and ended up running on the wider end of the recommended deck height range to be safe. Checking piston/valve clearance will be the final check.

Good luck!

JeremyD · JeremyD's Garage

Quote:

Originally posted by bbh03
I was able to use the caliper method with repeatable results on my JE 9.5:1s. The flat lip allows this if your caliper is narrow enough. The lip allows the 98mm piston to clear the 95mm head so it should be about 1.5mm wide. I cleared the method with Henry and ended up running on the wider end of the recommended deck height range to be safe. Checking piston/valve clearance will be the final check.

Good luck!

Did the same thing - solder on each quadrant.

Jeff Alton · 04-25-2006, 06:54 PM

I guess I will do it both ways again. The caliper method showed the measurement about what I expected......

Cheers, thanks for the help