How to Set Squish Area Harley EVO Twin Cam M8 head to piston clearance

This is very important part of building a motor that most people overlook. You must set up the squish area to have maximum combustion chamber efficiency. With combustion chamber efficiency you get two benefits. 1 - Maximum horsepower per given engine combination. 2 - Better gas mileage. These both happen because you get better atomization of the fuel. In other words you burn all of the fuel getting your engine to do more work from the same given amount of fuel.
The squish area must be set between .030 - .040 inch. It's best to shoot for .035 inch. This way if your measurements are a little off you will still fall in-between the .030 - .040 inch.
The formula for figuring out the gaskets you need are as follows:
If you piston protrudes from the cylinder - Base Gasket crush thickness (BG) + Head Gasket crush thickness (HG) - Piston Protrusion (PP) = Squish Area (SA) or (BG+HG) - PP = SA
In other words if my Head gasket is .020 inch. My Base gasket is .020 inch and my piston sticks out of the cylinder .005 inch my squish area would be .035 inch. (.020 + .020) - .005 = .035 inch
If you have all the measurements but you need to figure out the thickness of the Head Gasket that you will need, the formula is: (BG - PP) - SA = HG
So if you want a squish area of .040 inch and your Base gasket is .020 inch and your piston protrudes .005 inch you will need a Head gasket .025 inch. (.020 - .005) - .040 = .025 inch
If you have all the measurements but you need to figure out the thickness of the Base Gasket that you will need, the formula is: (HG - PP) - SA = BG
So if you want a squish area of .033 inch and your Head gasket is .020 inch and your piston protrudes .005 inch you will need a base gasket .018 inch. (.020 - .005) - .033 = .0.018 inch
If your piston is below the cylinder deck surface (Piston Recess) of (PR) then on the above formulas you must change the Piston Protrusion to Piston Recess and make the number a positive number and add it instead of subtract it.
Formula for Squish Area - (BG+HG) + PR = SA
Formula for Head Gasket - SA -(BG + PR) = HG
Formula for Base Gasket - SA -(HG + PR) = BG
If you need further help email me your phone number to [e-mail]. It's easier to help over the phone.
Thank you for watching and please like and subscribe.
James Gaskets - Part #JGI-17033-83-A - GASKET KIT TOP END
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[@ziparillomcmf1822]

Every video I watch and then rewatch I learn something new ..Thank You vey much for putting all the effort and patients into making these videos ..

[@Rapsgarage]

Thank you for recognizing how much effort I have put into these videos. Making them slows me down but editing SUCKS!! I edit them a lot! When I’m watching other technical videos I don’t want the extra talking I just want the information and nothing more. That’s how I make my technical videos. Again thank you for the kind words and thank you for watching.

[@ziparillomcmf1822]

@@Rapsgarage As a semi retired old fart I'm spending a lot of extra time on my bikes these days and your videos are the best I've found .Thank You ..From up here in Vancouver Canada..Cheers

[@theodavies8754]

It gets more tempting every time. While the tank's off and it's winter for the next few months.

[@Rapsgarage]

Do it!! It’s worth the effort.

[@michaeljanssen5089]

Great videos. You definitely do them like a professional should. No stupid music or dogs barking in the background, and you show that your work is more important about than where your beer is. As far as I’m concerned, your videos and videos like them are the only ones I would consider to be real, credible teachings. Thank you, sincerely, for taking the time out of your life to PROPERLY share your immense knowledge. I look forward to seeing more of your “classes”. Where can I send you an apple, teach?! God bless!

[@Rapsgarage]

Wow! Thank you so much! You’re making my head swell. Thank you for the kind words and thank you for watching. I’m glad I could help.

[@flshovelhead]

Very informative. I definitely learned something new today! The goofy thing is once you showed / explained the concept it almost seems like common sense, but I've missed this piece of info for years.

[@Rapsgarage]

Thank you! I appreciate your input. Most guys think I’m crazy when I tell them that this is important.

[@JCcanU]

KB are good I ran Forged and it was tight at under 150.00 a set . I always use 40th head gasket I like a 1/2 inch cam I know I have the little extra clearance . I only have Feller gage I stop there with a strait edge . Useless for me to use my run out gage with no deep gage . Great Video

[@Rapsgarage]

Thank you for watching.

[@goodboyringo9716]

I had KB piston in my Vette , worked great.

[@Rapsgarage]

They make a great product! Thanks for watching

[@johnliotta2583]

Used solder on the hammer 1275 kit to do this never thought much of it but it is key to not leaving any horsepower behind

[@Rapsgarage]

If it works… it works.

[@insideout2600]

Great videos . Rare someone makes them this accurate and good !! Thanks

[@Rapsgarage]

Thank you!! If you haven't, please subscribe. Thx

[@roncoburn7771]

but what about movement at the wrist pin because mine does have some movement great video

[@Rapsgarage]

It should have some side to side movement. You can get the amount from your manual for your model. It should definitely not have any up and down movement. Furthermore, when you rotate the wheels the rods should be free the entire way around. I’ve seen r rod get slightly tight when rotating it. If that happens then you have to pull it apart and do the bottom end. Thx for watching and if you need further help, let me know.

[@roncoburn7771]

@@Rapsgarage Hey thanks for responding Iam building a 131 ci m8 flywheels have been built by stanley gardner & grc with H beam rods deck height came out at 2.7 in the hole front cyl and 2.3 in rear..your video is the best on you tube

[@Rapsgarage]

@@roncoburn7771Thank you!! I appreciate that. Good luck with your build.

[@timryan7198]

Doing this tomorrow perfect timing! Thank you!

[@Rapsgarage]

That's awesome! Thank you for watching and if you're not subscribed, please do.

[@hardtailsuicidaljockey6827]

Learning more thanks for sharing 👍

[@Rapsgarage]

Thank you for watching.