Low Mileage stock bore Rod/Piston swap
 

Procedure: Yank off the head, drop the oil pan, unbolt stock rods, remove piston/rod assy's, hone cyl walls, install aftermarket rods/pistons into block w/o detaching the crank at all. Install new headgasket and timing components, and then go wreak havoc on the streets with a stronger (but not fully 'built') motor.

So I've heard rumors about this flying around on various forums, and was wondering if anyone has done this and with what results. Obviously this isn't like swapping out an alternator, and it's not the same as doing it 'the right way' and doing a full build, but this would be for strengthening the bottom end before disaster strikes, not waiting until there's a hole in the block :D Also, any comments on the procedure to make it work better, etc etc. Just looking for comments, clarity, and advice.

And for the record, I'm not thinking about doing this myself.

Re: Low Mileage stock bore Rod/Piston swap
 

This is what SleepyDSM did with his when the side of his piston melted. But he only did one new piston and all new rings. The only thing you need to do is make sure the oil holes on the head gasket surface are taped over or pluged so you dont get any of the metal from honing down there. Also we scrubed the block with hot soapy water to get rid of all the left over metal chunks.

But I would say its just as easy to pull the block out. I mean you have what 4 motor mounts to unbolt and the thing would "fall" out. To me taking it out would be less work then actually doing it that way. Just because then you can tip the eninge over and you have all the space in the world and dont have to worry about metal chunks maybe getting into the engine and staying there.

Re: Low Mileage stock bore Rod/Piston swap
 

You mean it would fall out if it wasn't attached to the trannyand thus the xfercase, axles, driveshaft, etc.

Re: Low Mileage stock bore Rod/Piston swap
 

I did rod bearings with only dropping the transfer case, oil pan and a cross member. But that's not quite pistons/rods.

When you think about it, you could swap them without even taking the head off, though.

Re: Low Mileage stock bore Rod/Piston swap
 

Yeah, I've done it, it can be done.

Re: Low Mileage stock bore Rod/Piston swap
 

Steve, do you have anymore to comment on? Longevity? Ease vs. yanking the motor, etc?

Re: Low Mileage stock bore Rod/Piston swap
 

How do you get the pistons past the crank? What about compressing the rings to install the new pistons?
Joe

Re: Low Mileage stock bore Rod/Piston swap
 

Right, gotta yank the head off, pistons come out the top!

Re: Low Mileage stock bore Rod/Piston swap
 

You don't need to take the pistons out if you're just replacing the rod bearings.

Re: Low Mileage stock bore Rod/Piston swap
 

Anyone else have any comments?

Re: Low Mileage stock bore Rod/Piston swap
 

:wontshare:

I really don't like the idea of ball honing motors in car.
I REALLY REALLY do not like the idea of half assing a motor build.

But if someone is on an extreme budget, I have seen it done, with scattered results.
:flamethrower:

Re: Low Mileage stock bore Rod/Piston swap
 

Like what? I know this isn't an ideal, stage 5, 8-second, bulletproof motor build, but bear with me. These tech threads are quiet and I *know* there are people here with experience here. If you have actual examples, please share!

I may not consider this myself, but other veterans have testified that this is a great way to add some insurance to your bottom end w/o going through a full motor build.

I have to say though, for someone like me, it's a pretty attractive option! This would open up the window to safely run a big turbo on my DD car w/o the hassle of pulling the motor and dealing with the hassle of several weeks of downtime while the motor is being disassembled, on it's way to the machine shop, at the machine shop, coming back from the machine shop, waiting on assembly, etc.


Think of it, a one or two-day job instead of weeks of downtime in a traditional motor build. Sure it it wouldn't be built to rev out to 10k rpms, but hey I'd have something stronger than the factory stuff and the wife would buy it if I told her that the car was in for a timing belt job :)

Re: Low Mileage stock bore Rod/Piston swap
 

Well it does have its pro's and cons.
It is cheaper than a full build and does involve less downtime..unfortunally with just a ball-hone you will be hard pressed to get the optimum surface finish on the cylinder walls, not that most shops even care about that.

I mean it does have its pro's and con's, I just feel weird towards the thought of doing something like that. It will allow someone to do it on the cheap, and the added insurance is much better than the factory stuff.

Re: Low Mileage stock bore Rod/Piston swap
 

I think that it's doable in a day. But like you're already thinking, it's not a bullet proof motor.

Re: Low Mileage stock bore Rod/Piston swap
 

Honing is very very messy. I would be most worried about the dirty, metal filled goo that is created when you hone. It's probably the last thing you would want in your motor. You need to somehow try to keep the honing residue from seeping down the cylinders onto the crank and into the crank case. You also have to try to avoid the oil squirters with the hone, unless you remove them. With a 1G or 2G, it is easy to pull the motor and you could still avoid removing the crank and oil pump assembly, but flip the motor upsidedown while you hone it. Pulling the motor on an Evo on the other hand does suck. If you wanted to try to do it with the motor in the car, I would try stuffing some rags around the crank, then cut a stock piston apart, leaving the rings, then inserting the piston back into the hole that you are going to hone upside down. Put some heavy oil around the edge of the piston and hope the rings stop most of the gunk from running down. I don't know if using a pistons in that way is feasible with the Evo though. The pistons rings might not be close enough to the crown, because it's a turbo piston or the whole thing might be too tall and end up keeping you from reaching the entire length of the cylinder wall that the rings contact.

Re: Low Mileage stock bore Rod/Piston swap
 

I know it's late but I did this with a minivan, I know it's not really performace minded but I did it in the driveway. I just made sure all the surfaces were really clean after and continued on check and rechecking bearing clearance. I had it done in about 6 hours work time. To add to ecoli's idea what if you just used a top ring wit ha bead of silicon arond to make a small reservior to catch that crap. That van has put 40,000 on since then and still running strong.

Re: Low Mileage stock bore Rod/Piston swap
 

Bump, just found an interesting article on this here:

http://forums.evolutionm.net/showthread.php?t=248904

Also, Buschur has boasted doing this on his bro's car with 50k miles on the stock bottom end. If I'm not mistaken, this is the same bro and same car that ran a 9.7 1320 on a BBT67...

http://evolutionm.net/forums/showthr...=256341&page=2

Re: Low Mileage stock bore Rod/Piston swap
 

The cross hatch looks realy shallow on the pics posted. There is more then one way to skin a cat, but I would not do a motor build that way.

~John

Re: Low Mileage stock bore Rod/Piston swap
 

In my opinion, this seems like a fairly half-assed way of doing a built motor and is just asking for premature failure.

Re: Low Mileage stock bore Rod/Piston swap
 

But then again you can have failures on new fully build motors. Slowhites motor was fairly new(I think) and It blow up (oil problem I think again) Nashs new motor popped. So fully build or half assed rebuild there all dsms in the end.
Joe