Who has a 82-84 Liq handy?

[kenwaters]

Joe,

I have found out the same information about squish band clearance. Even with the stock head gaskets, the squish band is still 0.010" too high to take minimum advantage of the squish area. Deere was EXTREMELY conservative with squish band clearance, probably to prevent the burn down issues with the Kawasaki Invader engines. I haven't turned any Deere heads and then measured the compression ratio, but the measurements I did take on my race engine suggested that if the squish band was corrected, the motor would have to run on premium fuel.

[Horicon Joe]

I checked the squish on my stock 84 liq and it was about .103. I need to check a few of my other stock original engines yet.
Kenny .. do you know what the stock squish band should be?

Joe

[Joliet Jake]

Joe don’t confuse squish with high compression.
Modern two strokes usually use a 50% squish band.
But the problem with engines having large bands is because of mass assembly.
If a crank has a tolerance of a few thousands gets assembled with a rod of the longest tolerance and that coupled with a piston with a wrist pin hole tolerance low and a dome height high, now insert them in a cylinder with a long height on a high deck height ………………….well you get the picture!
All these pieces are manufactured so no matter what part or parts are used the pistons don’t strike the head and a reasonably reliable engine is produced.

Most engines will run fine with .100 or so squish or even bigger …….the engine will waste a percentage of it’s charge and not produce max power but run fine.
Now when that engine is run to it’s limits that large squish will allow end gases to ignite and detonation to occur.

You can with proper gasket and machine work tighten up those tolerances.
but you can’t just mill off a few thousandths of the head as you may close the squish you may raise compression to a unacceptable level.
A good machine shop will mill the head but also mill the squish chamber itself thereby giving you a tight squish without a overly high compression ratio.

[AirborneX4Special]

Joe,

Ebay #110820912774

NOS set.

Bob

That kit looks correct, but the part number AM55588 does not show up in the Feb 84 Liquifire parts book, so I'm confused.

[harleysportster]

Joe,

Ebay #110820912774

NOS set.

Bob

That kit looks correct, but the part number AM55588 does not show up in the Feb 84 Liquifire parts book, so I'm confused.

It's correct, I boought the same kit last year from him.

[kenwaters]

Joliet Jake,

You are correct with your statements about squish as related to compression. Aaen Performance suggests that at 50% squish band area, the measured squish band should be between 0.055" and 0.070". I made the statements to Joe in relation to what Deere has done. When assembling the last Deere motor I put in my race sled, the measured squish band clearance with stock gaskets was about 0.105". When using a gasket thickness that actually uses the squish band to make power, the gasket thickness was 0.025" thinner, and made the compression so high that I had to run race fuel in it.

Joe,

I don't know what the stock squish band area is, I will have to draw it up on Solidworks to figure it out accurately. I can answer that the stock squish band clearance is about 0.105" (obviously plus or minus a little), when using stock Deere gaskets. When using aftermarket gaskets, the squish clearance is a little bigger yet, at least that is what I have found.

If anyone takes any material off of their heads, please do so under the guidance of someone that has significant engine building and tuning experience. Please don't assume that taking 0.010" off of your heads will fix these motors. Joliet Jake is right about interference tolerance stack-up and overly high compression ratios.

[shanes66charger]

Hey guys, I don't know if anyone in this thread is still here but here goes.

I recently sent my 82 liquifire motor up to Nothern Crankshaft in MN. I orginally told them to take .010 off the heads to bump compression up a bit. Upon further reading I'm not certian of that. To further confuse things I had 2 sets of Wiseco pistons both listed for JD applications and others. 2313M06800 & 2084M06800. I called wiseco tech support and was told that the only difference was the 2084s have a higher dome. .040 higher I was told. So .125 vs .165.

I sent both pistons to Northern as said to use whichever ones he thought best thinking maybe the higher domes would eliminate the need to pay to mill my heads. Now after finding all this squish band information I'm not sure what to do.

I sent NOS gaskets for the build and know they do a ton of custom work up there so Im sure they will check and correct squish as needed. Or I hope anyways. I'm not opposed to running higher octane if needed as I run 91 non eth currently. I just wanna be sure I know if I need to and that it will be done properly. I'm guessing the shape of the higher dome may be incorrect as well.....I'm ok paying for machining the heads in either case. Just concerned that whichever route he goes it gets done and matched properly and I'm not smashing a piston at 8k

Do you guys have any thoughts on this?