Hybrid

Yo fella's, this one is for the fellow techies.

Ok I have a D16Z6 with Y8 head, plus new Arias pistons set up for the Y8 head to bring compression to 8.5:1 plus they and the rings can handle the boost.

Anywho, you guy's with forged pistons, what piston to cylinder wall clearnance are you running. I know for my motor it is 0.0004 to 0.0016 stock clearance. Now Arias recommend 0.003 to 0.0025 range, some where around there. Now I think the pistons have the same diameter as my stock ones, have to confirm with my vernier caliper. Why do these pistons need such clearance in the bore? I mean I don't want terrible piston knocking. I know I'll get some of this with forged pistons anyway until warm up.

I will not complain about a new bore or align hone on the block, but is this necessary? This is for a mild street turbo application, 7-10psi. Also can anyone recommend a decent ring gap? I know arias recommend way over the stock ring gap for the 1st and second rings. Again I'm mild street turbo, not all out race.

Anyone want to go into this with me? The sooner the better as if I gots to haul the block I will be doing it tonight so I can get it bored and honed tommorrow and have it back for the weekend so I can rebuild and be rolling again by monday.




[Modified by Hybrid, 8:42 PM 5/30/2002]

BROOD

My turbo engine is using: (not JE pistons)
0.0028-0.0029" piston wall clearance
0.012-0.013" piston ring gap
It would more so depend on the piston manufacture's recommendation so I'd start with what they specify.

Turbo=more heat, more thermal expansion. Using those specs sounds like a good idea to me. Besides you have to hone the bores anyways to ensure a good ring seal.


[Modified by SLPR, 6:24 AM 5/31/2002]

Full-Race Geoff

2 to 3 thousandths is perfect (0.002-=0.003)

forged pistons need to be a bit looser than stock.

Hybrid

Hey guy's thanks for the quick responses, its much appreciated.

I was talking with the tech department at Arias last night but I just wanted to confirm with the people who actually use this **** ya know what I'm saying.

boosted3g

I follow JE's directions and went with 0.004 and i do get some rattle during start up and during decel in lower RPMs. I would go alittle tighter like was stated.

Full-Race Geoff

Hey how much does modified motorsports charge for dyno time? I am looking to go to a different dyno than ive been going to for a few personal reasons not particularly my car, but customers cars.

edit: BTW, dont use JE recommendations for anything. As far as ring gap goes, use stock honda gaps. 12 thou on the upper ring and 14 on the second ring works really well.




[Modified by FFgeoff, 6:09 PM 5/30/2002]

boosted3g

They charge 75 an hour with no charge for set up liek most places do. Its a nice set up, Mustang dyno and they have all the wide band stuff. I have known them guys for years and they recently started sponsering me. They were Honda techs for a combined 15 years or so then left to start the shop and its going good. Give them a call, we get a ton of guys that come from Jersey.

jeremyG2teg

Whatever you do, dont make the clearances too small. Or else your engine will sound like this.... http://rely.net/~dustin/jeremyengine.wav and your pistons will look like this....

This block was originally built by Comptech USA ( ), with Benson sleeves and Arais pistons. After the motor was disassembled we (Dustin and I) found that the bore was slightly smaller than stock. This put the clearances at about .001. I have no idea how many two year olds they have working at Comptech but one deffinitely built this block.


[Modified by jeremyG2teg, 2:29 PM 5/31/2002]

SiRkid

OUCH....ahahahahahahahaha
sounds like a diesel truck

Full-Race Geoff

as far as i know, all the old benson's sleves did this to pistons. EVERY single bensons block ive seen has this scarring on the skir to fthe piston. This is due to their use of cheap, poor quality grey iron sleeeves, not the nodular ductile iron tha GE uses. Golden eagle sleeves do not have this problem. detonation also causes this to happen, as can piston slap when the piston to walls are too big.