New rings won't go back in old pistons???

[Newboatowner]

Putting my 76 Evinrude 115 back together. The new piston and rings went in smoothly (well, tapping it in with a rubber mallet) I was going to re-use the other 3 pistons but the rings will not fit in the ring grooves. It fit perfectly on the new one. I took one end of an old ring to clean out any carbon build up and still no go. I hold the ring up to the groove and the ring appears to be just a bit too thick. I know I got the right rings. Does this make sense to anyone? I'm going to have to replace the rest of the pistons aint I??

[mackeral5]

had a similar problem when rebuilding an old merc 4cyl 100hp. ordered oem rings only to find they weren't compatible with the std bore wisecos that were already in the bores I was going to re-ring. in the end i had to order rings from wiseco. this may not be exactly what you're dealing with, but it is a possiblity.

[E-tec1]

the omc or pro type aftermarkets use the same ring that they have had for years, its the only thing i can think of

[Newboatowner]

I don't know what pistons I pulled out of it. Could be anything, they are .020 over so clearly not stock. Something strange with the piston itself. I had a very hard time getting the rings out of a couple of them. And with those same rings, I can get part of the ring in on one side of the piston but it won't fit back in on the other as if somehow the ring groove partially collapsed on one side. I don't know, I'm an ASE certified auto tech and have been up to the elbows in all sorts of motors.....never have I come accross a situation like this. This was suppose to be a $350 ring job that has already turned to $700 and now with this, I'll probably be adding another $225.

[bigbore]

With wire wheel,that'll b the only thing acurate enough 2 get the job done.:cool::thumbsup::cool:

[TheRickster]

Call around to some of your local machine shops and ask them if they have a ring groove cleaner.. It looks like a big clamp with a wiper on one saide and a wheel with several different thickness cutters for cleaning out the groove.. If you find one match the cutter to the new rings thickness and run it around it.. It will be a little difficult around the locator pin area but it might be an option rather than buying new slugs...

Rick

[Tom Foley]

Measure the old rings cross section thickness with a micrometer or very good caliper , should be dam near identical within a tenth or so ( .0001 - .0002 ) then look at the cross sectional shape of the ring and make sure its the same . If not ....you have some ash trays for the shop !!

[baja200merk]

the omc or pro type aftermarkets use the same ring that they have had for years, its the only thing i can think of

:iagree: i and ive seen the wrong rings in a looper :eek: no wonder it was such a deal on craigs list :rolleyes:

[Newboatowner]

Thanks fellas, the advice is appreciated.

[wrechin2]

If you had a hard time getting the rings out, then they are carboned up. Don't tap them in as they need to be loose and able to move. I bead blast pistons I reuse making sure the ring grooves are clean. I use PB blaster to remove the carbon in merc exhaust chest. You may spray them, let them sit, aggetate them with a tooth brush and it may remove it. The dremel ideal sounds good, just make sure you don't remove any material. Just my opinon.

[YELLOWSS]

i know in the late 70 or early 80's omc changed there design of pistons........
the cheap gas we had they decided to lower the location of the rings on the piston....
they could have changed the thickness too.......... just a thought.... i know in 77 was the older style, and i changed to the newer ones... check it out......

[Newboatowner]

I have some PB in my garage, haven't tried it though. I did let each of the pistons sit in a gallon of chem-dip for about a day. lol actually, I already did try to tap it in with my ring compressor over the rings...bent up the ring too. (i have an extra set though) Taping the ring in was scraping away at the top and bottom of the ring grooves. I better take a closer look at these rings. I know I ordered oe rings .020 over. I guess it's possible that the pistons the previous owner put in does not hold oe rings? If it aint one thing it's another :-)

[bigbore]

That'll get er.:cool::leaving:

[mackeral5]

can you find any casting numbers or part numbers on the pistons? this may help identify what brand piston and you may be able to order matching rings....

[wrechin2]

I just measured the rings on a 1979 high ring and a 1986 low ring. The top ring is .090 and the bottom ring is .060 on both. Can you measure the rings you took out and the new rings??? If they measure the same, it is defanately a carbon issue. Pretty common for the X-flow design. Some of the pistons I have the 2nd rings are pinned in so bad that you have to use pliers to get them out. After bead blasting, the rings fall in. I have 2 sets of pistons to blast today for rebuilds. I like blasting the pistons because it make them porus (spelling) and they hold oil. Very similar to knurling racing piston for 4 strokes. Also if it has any light scuffs they go away as it blends them in. Pretty neat to watch.

[Newboatowner]

Okay, I used my digital caliper to measure the rings. Measuring the ring set I bought and the rings that came with the extra piston I bought, they measure out to .064 on the money every one. I measured the rings I took out of the pistons and they measure .058 It seems to me like the person who previously rebuilt this motor used pistons from a differant year? They deffinately look like crossflow pistons though. The only markings on these old pistons is the .020 stamped on the top.
unless.... johnson and evinrude are identical right?? All the parts I bought was for a 76 rude. Mine is actually a 76 Johnson. I ordered rude parts because nobody seems to have part listings for a 76 Johnson 115. Those I've spoke with said "just get rude parts only differance is the sticker on the cowl"

[Newboatowner]

I'm thinking mackeral5 may have it nailed. I went to pro marine to see if they listed any differances between pistons. The description for wiseco rings were as follows:
<TABLE id=ProductDetail21_Table2 cellSpacing=0 cellPadding=0 width="100%" border=0><TBODY><TR id=ProductDetail21_trDescription><TD class=Content>
Piston ring set for Wiseco .020 over sized piston. Fits 2.5L V6 and some L3 & L4 engines with 3.520" bore size. Each set contains 2 chrome faced rings with 7º tapered semi-keystone design.

Wiseco marine piston rings are not interchangeable with original equipment rings. They fit Wiseco pistons only and the part number is the bore size followed by KD. Note: KD rings cannot be used in chrome lined cylinders .
</TD></TR><TR id=ProductDetail21_trPrice><TD class=Content noWrap>$29.95</TD></TR></TBODY></TABLE>

[Bruster]

I like new pistons in a rebuild, I don't think you'll be sorry when all is said and done. You should know anything you do with a boat is your estimate X 3 and you'll only be a little shy on your final budget.:cheers:


I don't know what pistons I pulled out of it. Could be anything, they are .020 over so clearly not stock. Something strange with the piston itself. I had a very hard time getting the rings out of a couple of them. And with those same rings, I can get part of the ring in on one side of the piston but it won't fit back in on the other as if somehow the ring groove partially collapsed on one side. I don't know, I'm an ASE certified auto tech and have been up to the elbows in all sorts of motors.....never have I come accross a situation like this. This was suppose to be a $350 ring job that has already turned to $700 and now with this, I'll probably be adding another $225.

[wrechin2]

That is the truth!!!!!!! Estimates are just that, a ESTIMATE! I always add $100 to $200 to each estimate, depends on size of job, and tell the customer that is for anything that was overlooked and things that may arise. Easier to give a customer a refund instead of asking for more money!!!!! I always get the part money up front and labor at then end. I have been burnt too many times tying my money up in their engines. If they don't have the money for parts, then they don't have the money for me to work on it.

I have one here now that I had only expected to have to bore 1 cylinder on. Well on I had measured and thought would clean up, Was out of specs and still not clean. So I put it on the machine and bored it also. So now instead of a being another $116 it is only $16 over the estimate. Just my thoughts.


The rings I measured were .060 on the 2nd and .090 on the top. They were OMC Factory pistons and i have used Pro rings in them before with no issues. I don't like wisecos and couldn't tell you anything about the ring dimentions. On the inside of the piston are there any markings???? They are probably some off the wall brand.

I looked and OMC doesn't list a 115 untill 77. I ran the oe number and it superceds to 396503 which would be the same as promarine 3920's. It also crosses to a sierra, mercury, and a mallory ring. So even a sierra piston would have the same ring.

Post what the numbers that are on the plug on the top of the left near the head. Ususally the older ones will have the year listed some don't.

Hope this helps.

[flabum1017]

I'm thinking mackeral5 may have it nailed. I went to pro marine to see if they listed any differances between pistons. The description for wiseco rings were as follows:
<TABLE id=ProductDetail21_Table2 cellSpacing=0 cellPadding=0 width="100%" border=0><TBODY><TR id=ProductDetail21_trDescription><TD class=Content>
Piston ring set for Wiseco .020 over sized piston. Fits 2.5L V6 and some L3 & L4 engines with 3.520" bore size. Each set contains 2 chrome faced rings with 7º tapered semi-keystone design.

Wiseco marine piston rings are not interchangeable with original equipment rings. They fit Wiseco pistons only and the part number is the bore size followed by KD. Note: KD rings cannot be used in chrome lined cylinders .

</TD></TR><TR id=ProductDetail21_trPrice><TD class=Content noWrap>$29.95</TD></TR></TBODY></TABLE>


Thatmight be it...... are the top ring groves in your pistons tapered?

[Newboatowner]

No, the bottom and the top ring grooves are identical in appearance as are the rings. The rings I pulled out have a slight taper to them, thicker where they meet the cylinder wall and slightly tapers down as it meets the piston.
The piston I just bought to replace one I pulled out has a larger top ring groove with the top ring having an aggressive taper to it, the bottom ring appears to not have a taper at all. The set of rings I bought (oe style) will fit the piston I bought or most other pistons I'm sure. But the rings I pulled out of my motor are completely differant than oe style.

[Newboatowner]

The number on the plug is 115ETL75E, the number on the tilt/trim section is 115ETL76G

[mackeral5]

the powerhead number is a 1975, the clamp number is a 1976.....

[Newboatowner]

Yes but parts are identical

[flabum1017]

Sounds like you have Wiseco pistons in it...... have you seen any identifying marks? Can you take pictures of all the pistons and post them here?

[Newboatowner]

Well, I thought I had wiseco pistons too. I spoke with a gentleman from Pro Marine where I bought my piston and bearings from. I explained all of this to him the measurements, angles of rings, thickness of rings etc. He to said it sounds like wiseco pistons. He said though that wisecos have identifying marks on them, a number usually stamped on top. Mine have nothing stamped on top except the number .020
Under the skirt directly below the wrist pin is an "R" stamped in. I can take some photos and TRY to post them here. Last time I tried to post photos I couldn't get it to up load.

[Newboatowner]

169508

169509

169510

169511

169512

Here they B :confused:

[flabum1017]

Those heavy oil grooves....definately Wiseco's

[Newboatowner]

Thank You, I suspected the same toward the end. I feel much better about dumping another $100 in it now. :thumbsup:
I'll order so wiseco .020 rings and finish the assembly. Scream and Fly rocks!!!

[wrechin2]

The color give it away that they are forged. You can see it on the piture of the bottom. I don't know of anyone else making forged for them. But they usually marked. May be really old! Sounds like ya got it figured out. Good deal.

[Newboatowner]

Yeah, WE got it figured out, I appreciate all of you helping me out on this.