Piston rings replacement help

[ivanr4g63]

My motor is 168k bone stock, well except for the head rebuild like 26k miles ago, I need piston rings really bad, the car runs fine at driving speeds, but as soon as I step on the gas and build boost smokes the hell out of the whole neighborhood, although its crazy because I do compression tests often and compression has never gone any lower than 150 psi, but the leak down test comfirmed piston rings... The thing is that beeing that motor is high mileage I checked crank and rod bearings and they seem in rather good shape, so Im replacing main and rod bearings and piston rings,

But can I do this all in standard size?

I guess I would love to go to a propper bore size, but im really on a tight budget, plus I cant have the car down for long...any input is gladly apreciated.

 

[Eclipsethis90]

Your rings wear the cylinder bores over time and when it is time for new rings...I would bore oversized to ensure perfect sealing and bedding of the new piston rings and fix the uneven bore of the cylinder walls . (uneven bore-the bore is larger where the rings have sealed in the last hundred thousand + miles, but where the rings haven't gone, such as the very top of the cylinder bore or the very bottom, the cylinder bore is smaller. Note, it isn't a lot of difference but I wouldn't rebuild without boring. You'd need to talk to your local machine shop also, sometimes if the taper of the bore isn't much the shop can use hone stones to take out most of it and give you a good surface to seal the rings too...and honing is cheaper than boring and oversized pistons .

 

[HybridAWD]

the only way you can be sure that you can is mic everything... then plastigauge everythign when doing the new bearings... thats the only thing i can tell you

 

[DragGSX]

Also along with what there saying...if your head still has stock internals it would be a good time to have valve stems seals and valve guides replaced(also a place where engine smoke comes from, more so at idle and taking off after idleing fer awhile)...again its not that expensive but since its allready off the car WHY NOT?
I relize you might not have the funds but the quick and cheap way is never the best when dealing with engine internals. If the car just smokes but runs fine...you probally could wait for a little bit longer and save up the money to do it right

 

[ivanr4g63]

yeah I did mention doing the rod bearings beeing replaced, and the head was fully done a while back, but thanks anyway, and thank you guys for your tips.

the cylinder walls are going to be honed of course, I've done a few high mileage engines in standard bore before (non 4g63), and they worked just fine surprinsingly, I guess what I was expecting is to hear from people who had rebuild their engines and leaving them in standard bore with the proper clearance check up and such, I totally agreed though that go overbore its best, but like I said Im in a tight budget and time is against me, so the car can't be down for a long time, and since I plan on doing a full rebuild as soon as time lets me im just looking to rebuild what I have and still leave it in good shape. Like I mentioned above the cylinder walls look in rather great shape for their age thats the main reason why I decided to go standard everything. I also find out that I'll need a new harmonic balancer so im in the market for that.

Thanks again, and if theres any more comments I'll gladly apreciate it.

 

[HybridAWD]

if you want a set of valve guide, ill sell you a brand new set i have, i didnt use them on my head. $75 + shipping.... they were bought from turbo trix last year... $9 each oh well i need the money .

 

[DragGSX]

as for the harmonic balancer...My engine is currently tore down and im goin to use underdrives when it gets back together so i have a used 92gsx harmonic balancer...if ya want it lemmy know...its just gonna sit here and collect dust...just pay for shipping and a lil of my time

 

[half-cocked]

It can be done in a day, pull the head, drop the pan and pull all the pistons/rods. You can get a 3 bar hone with 240 or 280 grit stones for around $25. Just make sure to cover up the rod journals to minimize contaimination. Make sure to get some new bearings, you can get Cleavites @ autozone for $7.99 a pop. If you can hold out get some ARP headstuds and decent headgasket and you'll be good.

 

[Bostedquest]

When I got my '63 last summer the engine had 20X,XXX on it. Stock everything. The kid blew the turbo 90K miles ago so the motor was fine. Everything was still in spec, but the bore out of round was higher then I wanted, so I had it bored out. Even the machine shop guys gave me flak about it. But hell it was only good by a few hunderdths. And I was prepping this motor for a T4E damnit.

Moral, it all depends on what you want to do, and how you drive. You running stock, or close to it... just re ring it do the bearings and call it done.
Then you can find another '63 and slowly build it up. I suggest everyone that owns a car rebuild a few engines. You learn alot. Just take your time, follow the book and your gold. It's really not hard.

 

[ivanr4g63]

Yeah, thanks, I did had a spare block but I had to sell it for space reasons, but I'll most likely find me another one down the road and rebuild it with time.

My pistons seem to have some kind of wrist pin play, so I'll end up spending more time with the car down... well I have to do what it takes to get it right...


thanks again for the replys.

 

[HybridAWD]

Yeah, thanks, I did had a spare block but I had to sell it for space reasons, but I'll most likely find me another one down the road and rebuild it with time.

My pistons seem to have some kind of wrist pin play, so I'll end up spending more time with the car down... well I have to do what it takes to get it right...


thanks again for the replys.

wrist pin play wtf

 

[WhiteAWDtsi]

My motor is 168k bone stock, well except for the head rebuild like 26k miles ago, I need piston rings really bad, the car runs fine at driving speeds, but as soon as I step on the gas and build boost smokes the hell out of the whole neighborhood, although its crazy because I do compression tests often and compression has never gone any lower than 150 psi, but the leak down test comfirmed piston rings... The thing is that beeing that motor is high mileage I checked crank and rod bearings and they seem in rather good shape, so Im replacing main and rod bearings and piston rings,

But can I do this all in standard size?

I guess I would love to go to a propper bore size, but im really on a tight budget, plus I cant have the car down for long...any input is gladly apreciated.

What were the results from the leakdown? sounds like your turbo seal is blown to me. at 150+ in all 4 i dont see how your rings are bad, thats great compression for that many miles. Could it just be your oil rings that are bad??? doesn't make any sense...try taking your lower i/c pipe off the turbo and have someone start and rev the engine(it will hardly run obviously), see if any oil spits out of the compresser side. could check shaft play too.

 

[ivanr4g63]

wrist pin play wtf

Happens when you have play between the piston itself and the conecting rod, sounds like a light knocking sound from the head. im surprised you've never heard of it.

What were the results from the leakdown? sounds like your turbo seal is blown to me. at 150+ in all 4 i dont see how your rings are bad, thats great compression for that many miles. Could it just be your oil rings that are bad??? doesn't make any sense...try taking your lower i/c pipe off the turbo and have someone start and rev the engine(it will hardly run obviously), see if any oil spits out of the compresser side. could check shaft play too.

I dont have the exact numbers of the leak down because it was done at a shop like 2 weeks ago, but yeah the leak down confirmed bad piston rings, they could be some how aligned or yeah maybe the oil rings went bad dont know exactly, now my rings aren't extremely bad, the compression test is high because the head is milled and also probably high carbon deposits, the car is still very driveable but when I stomp on the gas smoke goes all over, and no, its not the turbo, no shaft play, no leak of any kind, the turbo was also rebuild not long ago. valves and valve guide where all replaced 20k miles ago, the pcv valve has been blocked a while back so no oil going to the intake thru there either. I know for a fact that the rings need replacing, and I just decide to take my time and replace pistons and rods all at once.

Thanks for all the replys.

 

[Bostedquest]

Happens when you have play between the piston itself and the conecting rod, sounds like a light knocking sound from the head. im surprised you've never heard of it.
Thanks for all the replys.

The wrist pin is in the piston/connecting rod joint...
Your talking about rod knock... that is "usually" bearing play (sliding back and forth) against the crank.