Thread: Need advice on engine build.

So, here's the deal:

Pistons 1, 2, and 4 chipped on me a few weeks ago, so now my car is down with the block removed and stripped bare.

I'm having to put another set of pistons in it and am trying to get some suggestions on a direction to go with it for now. I am a college student and will be getting outside money to fund this, so I want to mix reliability, performance, and low cost.

I've considered buying the Diamond 9.5:1 pistons (since I found them almost as cheap as a new set of factory pistons) and slowing my blower back down to a more efficient level since I'm still using the Gen3 and no intercooler. Good idea or not?

Also, will I make the same power with the potential for more, or should I stick with the stock compression ratio and just continue from where I am?

Next question: Will I be safe reusing my stock connecting rods as long as they check out okay for reuse? Is it necessary to upgrade to the Series III rods?

Question #3: Valves. There is some trash trapped in the exhaust seat of #1, so I know it will have to be reworked somewhat. Also, all 6 of my ex valves are burned a slight bit. Should I get a new set of stock valves, or should I go with some aftermarket ones? What brand and size?

I'm sure I'll have more questions as I get further into this, but this will get me started for now. Thank you all in advance for your help. My current mods (collection of aftermarket parts no longer on my car) are in my signature.

How much you paying for the forged pistons? I found a new set of uncoated forged pistons for under $550.

if youre sticking with the m90 then go big with the compression ratio. it is much better to run a bigger pulley and make the same amount of power and it makes the car much more driveable out of boost.

rods dont break unless something major is wrong, there is nothing wrong with stock ones.

so long as you dont want to go with bigger valves im sure the stock ones are fine as long as they are still straight and seal okay when youre valve job is done. if youre looking for more power, bigger valves are where it's at for more flow. if i bought anything i would buy manley valves.

are you gonna opt for some headers??

thats all i got.

Scotty, the place you speak of for the pistons is where I'm going to get them from. You sent me the link not too long ago.

Bio, thank you for your info. That's exactly what I wanted to hear.

Rus, I do plan on going with headers within the following months of getting my car back up and running. I will most likely go with some of the cheaper ebay headers just for the value factor, however.

Originally Posted by DanGTP

Scotty, the place you speak of for the pistons is where I'm going to get them from. You sent me the link not too long ago.

Ahh, I forgot about that I guess. Sorry about that.

what is wrong with AFCs and happy knobs? i use both.

Higher compression would definetly be in you're favor with any M90. Stock rods should be fine although I just broke a rod in half...and a cam in half...and a block...and an a/c compressor...and a valve.....and destroyed a head and i'm assuming the piston is somewhere in the bottom of the oil pan


But that's another story that you guys will hear about soon.

say whaaaaaa?

Dangit Parker!! There you go getting me worried!

This isn't exactly a track car. It's my DD, and my only one, at that.
I think I'll go with the high comp pistons and slow the blower down. Anyone want to buy a 3.1" pulley?

Any other suggestions for what else I should do?

Okay, guys. I've been doing some parts and machine work shopping this past week and have some more questions.

1)Are there other manufacturers that make rods for, or that will work in, our engines? I've found plenty for the old buick 3.8.

2)How balanced are our cranks from the factory, and why are some shops unable to balance my crank? What's a good price to balance the crank?

3)I got a price quote on some work from a performance engine shop that didn't seem too outrageous. $325 for a tank, magnaflux, line bore, cam bearings and installation, new freeze plugs and whatever else needs to be done to the block. $30 to polish and check the crank. Do these prices seem too high or are they about right?

Originally Posted by TDCRacing

Stock rods should be fine although I just broke a rod in half...and a cam in half...and a block...and an a/c compressor...and a valve.....and destroyed a head and i'm assuming the piston is somewhere in the bottom of the oil pan


But that's another story that you guys will hear about soon.

Huh? Do tell.... Linky??

BTW, while you got the motor apart and have options, now is the time, get the forged slugs. As long as the motor is built right, it should be better than stock. Your pistons will be stronger making pistons less likely to chip as easily as stocks ones do. Its extra insurance I think thats worth doing, especially if your planning on going bigger and better in the future.

I am getting the Diamond forged pistons in a 9.5:1 CR and .020" over.

i disabled my balancer and left it in there. my car runs just fine without it and the only reason my car shakes is from the poly upper mounts i have. i dont see a reason to get rid of it on a DD.

hay Dan see if you can find a guy named Eddie Martin up there he is from Siloam.
he has got the bead on all the machine shops up there and if Im not mistaken he has one of his own, I know he has a fab shop where he builds and sells race cars.