flier129

iTrader: (7)

Got a cheap motor that shows undesirable low compression numbers. Put a little oil down the sparkplug holes and each cyclinder increased around 30psi. This points to rings, according to the good ole hayne's manual lol.


I've done some searching about piston rings and I can't find much recommendation on brands.

All I cam across was Ross Racing rings for brands.

On rockauto is shows two different types. One, Berk/Arnley at $72 and Sealed Power (premium) at $105. Are the more expensive ones just chrome moly coated or something? This engine won't be seeing any boost, just some N/A autox time, with the occasional track event with my ITB setup. I'll be being another one of my engines for boost in the mean time.

Does anyone else have any suggested on where else to buy piston rings?

Braineack

iTrader: (62)

I had bought the sealed power ones myself. good thing they were only $60 for the 1.6L

18psi

iTrader: (76)

Braineak got chrom moly ones and suggested them to me.
I got em and they're great.
I'd get those if I were you.


*edit: oh **** beat me to it

flier129

iTrader: (7)

Damn a $40 dollar difference between 1.6 and 1.8.

Question, I can still see the cross-hatches, which is surprising on a 150k mi engine. Will I still need to hone the block for the new rings?


Heres a pic of how the cyclinder walls look.


oh and yes there was massive carbon build-up everywhere. I think thats what led to the failed rings. I got most of the buildup off with some wd40 and elbow grease.

18psi

iTrader: (76)

make sure to clean them REALLY good. can't stress this enough.

and its always a good idea to hone when replacing rings. can't hurt

IHI

Got the same question here.
Did this: Took first motor appart as a cranck bearing failed. All was lost so bought a second engine. That was pitch black on the inside so I decided to pull that one appart too. In the end the first engine was the better one so now I am using both internals to create one engine.

I brought the engine to the machine shop and had it rehoned as the cilinder was like a mirror. It wasn't worn too far the machinist told me so just renewing the surfice did the job.

Now I haven't bought rings yet. I was looking on E-bay and ran into NPR rings. I haven't found the above rings so If please give me some adresses where to purchase them ? But does anyone knows anything about NPR ?

For a re-hohned engine, what rings could be used best ?

By the way:
I dropped my pistons in the ultrasonic cleaner that was new $150 and they came out as new.
In fact: I dropped in about any part that fitted in it and it wen't in very dirty and black sludge all over it, came out as it was just made at Mazda's plant...

flier129

iTrader: (7)

RockAuto Auto Parts is the supplier were talking about.

A ultrasonic cleaner would come in handy lol.

While were talking about pistons, what do you guys think about the condition of these pistons:

looks like some dentation


scoured sideskirts


Could I put some new rings on these JE pistons or are they shot? I can provide more pictures if the condition is in question. I'd also be willing to sell these at a reasonable price if they are reusable.

IHI

Looks like they are gone to me. The ones I considdered ready-to-bin were in better shape. I don't know what happened to the top one, all my eight pistons were in good condition on top. I had wear marks like you on the engine that still ran, but the one that had a bigend failure did not have those marks, or just a tiny bit.

Someone told me: the piston is just to close the hole. The rings will stop the leak. So you can renew them but it is a waste of money. But I do not think he would say that if he saw these pistons...

Thanks for the link.

flier129

iTrader: (7)

Yeah, my first thought when I pulled them was "**** they're trashed". But I started to talk to a local raceshop owner and he said they may be salavagable. I really need to take them to him so he can look them over. Pictures over the internet can only do so much.


On the plus side the top of the pistons looked fine. Just some carbon from way too much fuel when I installed the 550cc injectors.

IHI

I wan't studs like that !
I have a lot of things to do on my engine but I am stuck on not heaving piston-rings at the moment. I was looking at that engine-parts shop and it looks like a big candy shop to me. Thanks again. Saddly I am in Europe. Here is a set of rings €100. That would be like 135 dollar or so. And you will get some unbranded stuff. So for me it is a lot cheaper to look for good shops in the US that do a lot of volume and have therefore reasonable pricing.

I can spend like a ton on that little engine. Plain stupid but it all adds up.

johnmatt

iTrader: (8)

I'm actually going through the same thing with pistons right now. So if the top is starting to look like that they're not good anymore?

magnamx-5

iTrader: (7)

nah man look at the side on the first piston you can see how it looks eaten away this would indicate to me that maybe the bore piston clearance was to tight and he was getting abit of slap on cold startups. Detonation would have pounded the top of the piston and eventualy disintegrated the ring lands. Just like mine and braineacks first motors did.

johnmatt

iTrader: (8)

yeah I saw the wear on the sides. I'm talking about the damage on the top above the ring.

miata2fast

iTrader: (2)

Those pistons will make I nice addition to your scrap pile. Get new pistons and sleep well at night.

magnamx-5

iTrader: (7)

well considering he didnt show us the piston out of the motor from a top down view we cant realy tell but i say replace em and be done with it. any sign of damage whatsoever is nothing i want to keep in my engine voluntarily.

miata2fast

iTrader: (2)

Piston skirts are designed to hold oil. The bad scratches will prevent oil from floating between the piston and cylinder walls. It will undoutedly cause premature wear to the cylinder walls.

A good piston has grooves that collect oil. Worn pistons are smooth, and do not collect the oil to keep the piston away from the walls. A badly scratched piston will let oil leak away from the grooves and allow the piston to come in contact with the walls.

Use them as paper weights or practice your free throws into a garbage can.

flier129

iTrader: (7)

Took them to a local machine/race shop, took my rods as well. He had decent hopes for them until he saw the pin boss on #4, trashed.

I really wasn't wanting to reuse these JE's myself, I hoping maybe someone might want them for a cheap engine build for their weekend toy or something.

The shop owner said I could reuse the 3 and buy a single new one, if I really wanted to. Then he started to ask about costs for new pistons and he immediately said get all new pistons, lol.

The rods I thought were 100% fine, but turns out the guys who first assembled the engine (yet another stupid decision to buy a "assembled" motor with no paperwork) had put the rod end-caps on backwards, causing abnormal wear. The bushings on the little end are also worn, so the rods need to be refurbished, which will probly run $50-$60 per rod. I'm considering this since the Crower rods are around $750 new, although the m-tuned rods are close to same price as doing a refurbish.

Hopefully my troubles can help someone else not make the same mistake, heh.

IHI

Just bought a set of prenium rings for the 1.6. I hope they are good. Now I have to look out for some springs for the small-end. I don't wan't to re-use them.

Amazing how hard it is to source all the parts required for an engine rebuild. Seems like no one has all the right bits.

93whiteMiataJDM

How have those rings lasted over the time for you? I see those same rings on rock auto and am thinking about buying them, but with all the options am skeptical.

Midtenn

iTrader: (15)

We've used Sealed Power rings in motors we've built for Champ Car (naturally aspirated BPs) and never had a problem with ring wear or failure.