Need help with piston rings!

[Brian O Conner]

Okay, this post is going to be hard to follow but this question is also for 4g63 people as well a matter of fact your help will be as helpful as the 420a guy in this question so I do need you. When I bought my car it was not running a guy with a 420a turboed eclipse cut me a deal for a trade for my 600 dollar camaro(2 years ago) When I took my block and head to the machine shop.

I had them check the parts out. I also had them order the valve springs, locks and all the aftermarket parts for the head. I had the Crower cams and the Machine shop owner offered to put the head together. So I let him. At the very start of me going over there I mentioned my car was a 1998 eclipse gs. I did state it was the 420a to not get them confused with the 4g63 at the start. As time went by when I called to check up on it. I always called it the 4 cylinder 2.0 l chrysler engine to help avoid the confusion of the Japanese counter part the 4g63.(they were a small machine shop in the middle of the country they worked 95 percent on muscle cars big v8s and v6s.)

So there wasnt any 4 cylinder engines at the time. When months would fly by. I got concerned. I would call and they would say the same thing. They got the parts checked out and parts showed up but they still were assembling the head. I waited patiently ANOTHER 2 MONTHS! Friends and people I knew that were into cars were getting concerned finally. I thought about it. These people werent familiar with the import world. So they could of easily got the 4g63 parts instead of the 420a parts. I called the shops owner and I asked them. What parts did they order and I also asked that they werent 4g63 parts were they and he said I thought you had a 4g63? I said no its the 420a engine thats why I kept reffering to the Chrysler 4 cylinder engine to throw off the mitsubishi 4g63 getting mentioned to not confuse you and get things mixed up. He said no problem I will send those parts back and order you the right parts.

In two weeks they finished the engine. The head was assembled good and precise. I checked almost everything to make sure nothing was for the 4g63 like the melling oil pump, waterpump, timing belt and other things. They all were right. Me and my stepdad just started working on the engine after I was buying all the parts I wanted to get. We were doing the preparation of cleaning the block along with tap cleaning the holes where the main studs and the head studs go. After that we started assemblying the Pistons to the connecting rods.

Then we went to put the piston rings on. He noticed the rings were really big. He asked me to get my digital caliper to measure the top groove rings. It measured about 3.670 inches. Then we measured the old top groove rings that were on the pistons originally and they measured 3.620 inches and He knew we would have to file some off of the new piston rings but almost 0.050. My engine is bored 40 over. I also am wanting to know the piston top groove ring measurement for a 40 overbore 420a. AND WHERE I GET AT HERE DID THE MACHINE SHOP ORDER RINGS FOR A 40 OVERBORE 4G63? Thats where I need the 4g63 guys to come in.

Anyways thanks for awnsering this long thread. I am trying to figure out if these piston rings are for the 4g3 or not. The after market rings are total seal rings any questions on part numbers to help get my question awnsered feel free to ask.

 

[BogusSVO]

What brand and part number do you have on the ring box?

 

[Turbotsiawd]

Wow did they AT the very least give
You a discount for the long wait?

 

[Brian O Conner]

I wish but they were good at price matching. Not to mention they were nice people just a confusion on the DSM world. I saw it coming but I thought my speachcraft would throw them off of the 4g63 by saying Chrysler 4 cylinder and telling them it was a 420a the engine in the neons but I did say eclipse and thats how they got confused. Anyways as of the update on this I did indeed look. They ordered me the right rings for my car but my problem now is the rings are standard size while my block was bored and honed .040 over wouldnt I need rings that were 3.485 instead of the standard 3.445? It doesnt make since the whole thing I am about to make a video to explain my problem here.

UPDATE To my knowledge if my cars block was bored and honed 0.040 over woudnt my rings have to be 0.040 bigger? The rings he ordered for me were in the standard size but I dont think that will work. I think they mis ordered the rings not sure.

I ALSO REMEASURED EVERYTHING MY ENGINE IS 3.485 inches for the cylinder diameter

 

[erock1399]

I well call them up and fight with them.

 

[necrotopsy]

you can buy pistions designed for the bigger bore (88mm is stock, you can get 88.5mm), or over sized rings, or both.

Bottom line:
If you're bored .040 over, then you need to compensate for that bore.
.040 rings + stock pistons = good
0.020 pistions + .020 rings = good
stock rings + stock pistons = BAD

 

[dsmcrzy]

you can buy pistions designed for the bigger bore (88mm is stock, you can get 88.5mm), or over sized rings, or both.

Bottom line:
If you're bored .040 over, then you need to compensate for that bore.
.040 rings + stock pistons = good
0.020 pistions + .020 rings = good
stock rings + stock pistons = BAD

That does not sound right at all!! The whole reason they sell bigger pistons is for the bore! You put in .02 rings and .02 pistons in a .04 bored engine your pistons will slap the head for sure! Everything u posted was wrong.

Brian is bored 40 over so he needs 40 over pistons and 40 over rings for it to work right.#

 

[2gnt]

you can buy pistions designed for the bigger bore (88mm is stock, you can get 88.5mm), or over sized rings, or both.

I'm pretty sure the stock piston size for the 420A is 87.5mm so 88mm would be .020 over.

As for rings, i would think that if you don't know what size piston they are for you can try sliding them into the block and measuring the ring end gap.

 

[Brian O Conner]

I found out it is bored .20 over The whole time I thought 0.040 over but that was because the machine shop told me that. I think they got it all mixed up. I did not know the stock bore size and on top of that I did not bore it over(the person before me did). Man they made this confusing. As for the pistons they are the 8:8:1 pistons that are 88mm. Yesterday I looked all over the internet for the je part number and there site would not read it. On top of that the search showed only two options then today I searched some more and found the P/N on a option all the way down the page. Man I hope the bearings they ordered were right.