I'm currently building a a6/y8 Vitara setup, I'm gonna be using the FJ custom length rods and according to the honda compression calculator, my piston to deck height is gonna be .003" in the hole.

The head that I am using is a rebuilt head so it has been milled but I don't know how much.

And according to the machine shop guy, He normally takes .005" off when decking the block.

That will put my pistons out of the hole a bit at -.002"

Am I gonna run into any problems with this setup or is this ok? Will I need to clay the piston to valves or am I pretty safe?

Thanks for any help.

 

You'll be MORE than fine with that 7.4:1 compression

 

i ran my vitara motor at that 7.4:1. i tell you what the car was loving timing on the dyno. it made good power for what it was, and ran 13's no problem.

the Only downside to it was i noticed a decrease in mpg a bit because even with adding a few degrees back in the map in vacuum i felt that i was always driving around at like 5" vacuum rather than at 10 or 15 inches

 

Actually, the compression ratio is gonna be like 9:1 with the FJ rods, These rods are longer than the stock rod length.

 

So since the vitara's are dished I should be ok? Even with the longer rods?

 

By how much? I'm curious as I'm not a D-series aficionado

 

Well the stock are 137mm and the fj rods are 138.63 mm according to the site. They are made so that the compression isn't so low. According the the compression calculator I should be right at 9:1 compression because of the smaller y8 head chamber. From what I've read the stock piston/deck height is at 0.0 So I'm guessing I should be good because if anyone has had a stock motor decked, that would put them at least a couple thousands out of the hole as well.

 

Really need a definite answer on this before I send my block off to get machined.

 

have a nice day

 

I was going to use the y8 2 layer gasket which is .025"

 

If you piston is out of the hole its going to slap the head especially since its vitaras there have alot of PTW clearence. Take it from me ive been down this road with pistons out of the hole. There is a minimum clearence for a reason. stick to it.

 

Well, went ahead and ordered some eagle normal 137mm rods. When I get everything in I will check my actual piston to deck height and if their out of the hole with the FJ rods then I'll throw in the eagles instead.

 

You can do that or run a thicker HG but thats not something i personally like to do