Have a del sol with a comp reading of 180 in 3 cylinders and 60 in the 4th in a d16z6. Dropped some oil down the spark plug hole and the comp went up to 120psi so i know the rings are shot. Wanting to replace the whole motor but having troubles finding a good one, so is changing the rings and bearings only on the bad piston the worst idea possible? But only fixing it temporarily until a good swap candidate comes along

 

Don't half *** it, Ring and bearing the rest as well. It's all right there anyhow.

 

x2 for young tom

 

i understand what your saying but its $100 verses $200 when i'm just gona pull the motor out in a month or 2 anyway to build for boost and replace EVERYTHING. Just wanting to drive it a little and not have to jump on the first motor that comes up that could be good or bad

 

Clearly you don't understand. Why are you asking when you know the answer but don't want to do it. If you're going to half *** it just do it and don't waste peoples time asking for advice on common sense stuff. Do them all. Just in case you missed the point: REPLACE ALL.

 

As long as you have the head off I would change all the piston rings because you'll probably buy a set of four rings anyways. I wouldn't worry about the bearings at all as long as the oil pressure was okay and there wasn't any metal pieces in the oil. Make sure you take a good look at the cylinder walls in that low cylinder for damage...60 psi is pretty low and who knows what the problem is. Check out the valves faces and the seats in the head to make sure there isn't any nightmares there. Slap it all together and it should hold until you find a new (used) engine.

 

I don't see how I'm wasting peoples time asking a question on a tech forum with a VERY specific title. But I'm only doing one because this will be a dd or sunny day car till the motor is FULlY rebuilt in about 3 months. Don't see the point in spending 4x the money when this is just a quick fix until everything is replaced anyway. Ill check out the cylinder and head for any unforseen damage before I throw it back together. But Ill let u know if the car bursts into flames as soon as I put the head back on after only doing 1

 

Hi there, sorry for breaking in with my rookie question when you are actually looking for answers to yours, but I really need your advice. You said "dropped some oil down the spark plug hole and the comp went up to 120psi so i know the rings are shot." How does that work? Why does compression go up when you put oil down the hole?

I am asking this because I suspect my piston rings are going out, too. I have a 2.3 liter engine with 195,000 miles on it and I've noticed that it eats motor oil! I've driven about 800 miles since I bought that car and today I had to top it up with about a half a liter of motor oil... I am going to measure the compression as soon as I can, but what's this trick with oil down the hole? Thanks!

 

just replace one all its gonna do is offset the balance and wear down your bearings faster is all.

 

it helps the rings seal against the cylinder wall. its a backyard trick to let you know if you need rings or not. a compression test will not determine if you NEED to replace your rings. it could be valve seals too. but the oil is a good informant of required repairs.

 

this was something i was thinking could happen. If the bearing doesnt show any signs of wear i'll just reuse since this is TEMPORARY and by no means a permanent fix.

 

So why even bother doing anything now? I'm sure as a DD it will last another 30-60 days...

 

^ exactly,
if your going to rebuild it why the hell would put a new rings in it now? the block has to be honed for proper seal anyways, and i have never seen a place sell only 1 ring set.

 

Honda sells rings and bearings by the set, the car was justbought by mygf and wants todrive it one way or the other, felt we got lucky on the 5hr drive home, no one has a z6 motor around here to swap in it and the amount of oil coming out the tail pipe isn't to reassuring to drive at all

 

Don't do anything at all, wait until you are doing the "fully built" if you truly are. I suspect you aren't or you are "hoping" to have the funds to do it in 3 months.

 

dude seriously? it costs like, 30 bux for a set of (that's rings for ALL FOUR pistons) npr rings on ebay. if you are THAT worried about keeping cost down, and are totally convinced that you are replacing the motor soon, simply mic the crank and plastigauge the existing rod bearings, and have a machine shop re hone the block. it cost me 350 to have my head resurfaced, have the crank mic'd and micropolished, hot tanked the block, checked all clearances, honed the block, and had them order me all new rings and bearings. then i bought new head bolts from napa and a full gasket set from ebay.

or better yet, just buy this. it's cheap, it will get the job done, and you'll atleast be able to re sell the z6 when you're done for a decent price.

http://cgi.ebay.com/ebaymotors/92-95...Q5fAccessories

oh and one more thing, if you have the money to spend on a random used motor, what do you have to lose by rebuilding your current one instead?