Need suggestions on rods and pistons

[milby43]

So Im burning oil, and we did a compression and leak down test.
Cylinder 3 i believe it was, has bad rings. So right now i wanna get some suggestions on what rod/piston combos i should get.
( sad thing is, good compression across the bored though. i know the numbers were 170 165 150 and 170)

Im looking at 1g big rods with 2g or evo pistons.
But for 1g big rods, you have to do something to them to make them fit a 7 bolt crank dont you?

I cant spend alot, so try to keep it cheap,

Also how long, or would it even come to, would it take for the rings to be completely beat and not hold any compression. And basically become a dead cylinder.

Ive been looking around for piston/rods. The only question I really have is, how do you know if certain pistons and rods will work together? And how do i know it will be alright with my crank, etc, etc.

i couldnt really find anythink like a write up about selecting pistons and rods.

Any other advice or ideas would help greatly.

Thanks.

 

[motozachl]

150 compression is not bad at all. Did you put oil in the cylinders to confirm it was the rings? Aka the compression went up...

 

[milby43]

150 compression is not bad at all. Did you put oil in the cylinders to confirm it was the rings? Aka the compression went up...

yea the one went up to 175. My brother whos good with these cars was helping me with it too.

Its got 130k miles on the internals, and Im sure the previous owners beat it.

 

[ziggo0]

What did the leak down say about cyl 3? Meanwhile 150 isn't as great as 170, it's not below the service limit (130 IIRC). I say run it till it gets worse, in that time frame you can save some cash. Does your motor already have 1g rods? I don't know when they switched over to 7 bolts...I think it was right around that time.

 

[motozachl]

...it's not below the service limit (130 IIRC). I say run it till it gets worse, in that time frame you can save some cash.....

120 and ditto

 

[BoostedBeaver]

Like stated above the 150 reading is not within 10 of the other reading but it is not that bad or below the service limit. Also you did the check with the motor at operating temp correct??? As far as your question goes we need to know your goals!!! Daily Driver??? Weekend Warrior??? HP??? As far as cheap goes think of these three words Cheap Fast and Reliable now pick two. All piston rod combo's are going to cost something there really is no cheap route. Then you will have to have machine work done. Just trying to put things into perspective before you get into a build and can't finish it.

 

[milby43]

leak down put #3 to 180 i think it was.
Yea im running it till it goes, so i can save cash.
Just to clerify, does that mean when im using the car its running good compression correct?

What are the chances that the bore or cylinder itself is ####ed?
And machining is a must when replacing rods/cylinders?

Mines a 93, I thought 1g rods were on the 6 bolt motors. But maybe im wrong.

RobertBaxley
Yea i understand, it was done with operating temp.
Anyway, what would a cheap street/Daily setup be. I would think the cheapest yet strong combo would be 1g rods and 2g pistons right?

And yea the cheap, reliable, fast thing i knew of .

 

[DSMTyson]

You would need to get the cylinders honed to ensure that the rings will seat properly/fully. Your cylinders are probably fine, just need to be honed. If I were you, and this car is just a fun daily driver, I would just stick with 7 bolt rods and 7 bolt pistons. They will hold plenty of power for a daily driver and won't require an machining.

BUT, if you decide to use forged internals.. Ross piston/Eagle rod combo is the best bang for the buck.

 

[JacksonAuto]

Just do it right and go .020" over with a set of good pistons. Chances are that honing wont bring them back into round. Kinda' defeats the purpose of a "build" if your new rings don't seal. If you're on a budget, buy a set of oversized replacement pistons. Have the block decked, bored and honed. Check the rods and resize if necessary and assemble with new bearings. It'll be 100x better than new.

 

[herms99gst]

I know a lot of people will use the standard bore if its within limits, but I've read several times that if u want a proper ring seal than u should go up to the next size.....20 over. This way the rings have a fresh surface to seal against. Like stated above, just because u rehone the cylinder does not mean the rings will seal properly. The cylinder could be out of round or have a slight taper like most engines will with miles on them. I paid 225 for my machine work on my block, its cheap insurance if u ask me. And for the best seal possible, have them use a torque plate.

 

[milby43]

Yea, what would be a round about cost of the machining needed. I just kinda want to get a little beefier rods to be a little more safe. And of course when i do all this im getting ARP head studs and a 4 layer head gasket.

 

[JacksonAuto]

It's going to vary depending on where you take it. Make sure you find a shop that specialized in mitsus and has a torque plate. Shoot me a PM if you want to get you a quote.

 

[milby43]

well you know what, Im going to Automotive Training Center in June. Itll last till then, ill get head studs and a gasket in the mean time. They have all the machining tools and such. Plus itll be free and i can learn to do it (not by my self of course).

MMMM, free port and polishing