Hey does anyone know the piston height for stock b18b pistons? Also the squish area for a stock b18b motor? Piston height is the distance from the center of the piston pin to the top of the piston. I can't really give an accurate description of what squish is at the moment. Please hit me up if you know these values, thanks.

J

 

can you explain better. not sure about the piston height. compression height, deck clearance, rod length, deck height,...got all that. not sure what you mean on the piston height though LOL

 

ya i guess what i described is compression height lol


i guess im really not sure what piston height is then lol, im using automated design engine simulation software. On the other engines ive done i have always had the specs I needed and at the moment I do not have the values for "piston height" or "squish clearance". Il do more research tomorrow and let you know what I find.

 

Compression height is 30 mm
Can't remember if its the right technical term but the "squish clearance" is about 0.039 inches

I used this link to get the information
http://www.zealautowerks.com/

 

squish clearance? WTF?? LOL did you mean deck clearance? (it will be a -number) or should be LOL

 

Its meaning is the top of the compression height to the the bottom of the head. It needs to be in a certain range to help fight off detonation. I was using the term that the original poster used. I can recall the actual name of it though.

So if you take the piston to deck height
0.013 inches

And the head gasket thickness
0.026 (OEM)

It leaves you with the
0.039 inches

If I can recall the range should be anywhere from 0.030 to 0.040

 

k so found an article about head porting that mentions "squish" or queching as it seems to be commonly called. Squish clearance is basically the distance between the top of the piston at TDC to the top of the combustion chamber.

"Some head specialists also modify the quench zones of the cylinder head's combustion chamber. The quench zones are the flat areas of the cylinder head where the piston comes in close proximity to TDC. Pentroof DOHC cylinder heads typically have four quench zones at the ends of the combustion chamber. Quench zones promote more complete burning and reduce the likeliness of detonation by increasing turbulence of the fuel air mixture as the piston comes to TDC by squishing the fuel air mixture toward the sparkplug and away from the end zones of the combustion chamber. This reduces the amount of fuel-air mixture near the ends of the combustion chamber where it does not completely burn (thus being wasted) by pushing or squishing it toward the centrally located sparkplug where it can easily be ignited. When heads have additional quench area, they normally need less timing advance to make power. Thus a skillful tuner can tune the engine to be further from the detonation threshold, making the engine more reliable.

The quench zones can be welded, milled and reshaped by hand to make them bigger, shaping the combustion chamber like a cloverleaf instead of the stock pentroof rectangle. This reduces the combustion chamber volume, increasing compression as well as making the quench zone more effective. This can also make the combustion chamber less likely to promote engine-damaging detonation because the turbulent air/fuel mixture squished by the bigger quench zones burns completely and smoothly. AutoPowerDesign's Stage 6 modification is a good example of a modified quench zone. In fact, AutoPowerDesign pioneered this technique for modifying four valve heads." Mike Kojima-modified.com

yea that sounds about right for the squish clearance, .039 in or .9906 milimeters. thanks man

 

you are correct on that i generally like a -0.002 deck clearance and a 0.040 cometic head gasket (MLS) with a stepped deck (+0.002) using darton dry sleeves in my builds. mainly N/A or turbo set ups.

 

Thats what the program asks for "squish clearance".

 

damn thats a good article. i could get rid of my machinist LOL but i wont cause i'll probably screw it up LOL

 

ya i can assemble fine but wouldnt trust myself to machine the head.

 

yeah those machinists are a dying breed it seams LOL

 

The set up I'm about to start running has a piston to deck height of 0.004 and I'm still going to use the stock head gasket. I wish I would have gone with the B16 pistons and have a little more piston to head clearance. I really like inline 4's B16 pistons and If I have to replace my pistons I'll end up going with them. Here's the link

http://www.inlinefour.com/il4peprpi.html

 

yeah i'm on the custom je pistons with teflon coated skirts, and double oiler wrist pins using K-1 connecting rods. 87 mm for turbo and 89 mm for N/A. 13:1 for N/A and 9:1 for turbo. these have been great but pricey. maybe i'll try some other piston (like the one in the link) in a build soon