build question

okay well here is my situation. i have about 4 motors to choose from for my rebuild, right now in the car im running a d15 block and a y8 head with full obd1 conversion, and a mild comp cam, all sorts of xtras, blah blah blah. any ways i have a sohc ZC block with fresh bearings in the bottom end but a bad piston in cyl 4, block is fine though. then i have a complete d16a6 that i got for free that i havent touched yet, and i have an extra d15b2 block layin around. i just picked up some p28 pistons

if you were in my situation what motor would ya use? the 1.5 or the 1.6 since im going higher compression i can make more in the 1.5 with the work im going to do, i belive. but the zc is apealing too. anybody got any input on this? i probly will go with the 1.6 but would like some input.... if anybody still uses this fourm anymore that is

Thanks,
Paul

nobody is home = go with the a6 bottom w/ the y8 head

1.5 more compression? hey im kinda in the same situation...except w/ only an a6 and a d15b2...oh yeah and both of the cars to go w/ it. b15b2 sedan (which im fond of), and a d16a6 hatch( rusted out).sorry...but i would say stick w/ the A6 use any thing u can from the other motors, or even do some reserch on that zc, and what its capable of.

well i did the reaserch using the d series compression calc from zeal works and im going to get a more manegable compression ratio for my buget using the 1.5 block witch was 11.66 to 1. with the 1.6 block and the head work that i have planned, and the p29 pistons i was 13.54 to 1 witch may be a bit much for the buget i have for tunning afterward. anyways i apperciate the input. keep it coming i dont have to decide witch block im going to use for about another week, when the head comes back,

Ok, I'm confused here. Haven't looked into building a high c/r d in awhile, but going off the zeal calc, its showing p28s as stock d16z6 pistons, which are not the high compression pistons. Those would be the pg6 pistons from the d16a1...unless zeal has them backwards, but I don't think they do.

Even then, on a d15 block with a y8 head, I'm coming up with 10.63:1 c/r without using a 2 layer head gasket, or decking/milling the block and head. Now with a d16 block and y8 head I'm coming up with 12.22:1, which is still workable, just takes a little more tuning, which either one will take.

The biggest thing you haven't answered though, and yes anytime you ask for help on a build, you have to answer this: what are you wanting to do with it? There is no perfect answer to all of them, it all depends on what you really want to do.

yeah sorry the p28 was a typo, they are p 29s, the car isnt on the road much, mostly just on track days, i really dont have a specific goal with the motor, just want to make something more than what i have, and can beat on, i decided to go with the 1.6 block,just casue they already have new bearings in the bottom end

Still check the bearings, do you know what happened to the piston? Fresh bearings don't mean anything if something major happened and they ended up getting damaged right afterwards. Always double check the measurements, especially if your building a motor trying to get everything you can out of it.

Still, what kind of track? Getting a full answer on this will help you on your build. To get the best setup for what YOU want to do with it, you have to know what you want to do with it, where you want to mainly race it, where the engine is going to be spending most of its time, what RPM range you are planning on staying in. If you find all this out, find out what tires your gonna be running, what transmission gears, etc. any little detail, you can a setup you want. The cam is the biggest deciding factor on where the engine is going to make its power, if you know these things, you can call a cam company and talk to them and they will get you setup on what you need, but you have to know your plans and everything else first.

If your drag racing the car, Torque is greater than HP, HP only determines top speed, torque gets you there. Torque is real, horsepower is a mathematical equation.

any body know the service limit for a y8 head off the top of your head, i have had to take a lot off my head to get some pits out, so how much can you take and still be safe? im going to clay my pistons and see where im at but was wondering if anybody knew off the top of your head. but as of now with the head work compression via the zeal werks Calc was abou 14.5 to 1 witch is redicoulus i know, think it can be run reliably? i know theres going to be a lot of tuning to go along with it and ill be running 110 octane fuel. looking for some input, i still can go with the d15 and would be runnign someware around 12 to 1 compression, the cars going to be daily driven ocasionally, and its going to spend a lot of time getting the shizzle revved out of it