88 7.3 rings where to find these elusive creatures?

[76ford466]

We'll since I can't leave things alone I tore my bottom end apart. I have a 7.3 1988 from f250 truck. Found the rings was wore past spec manual I have says 0.045 gap on top ring I had 0.075 and 0.085 on second ring. Pistons looked good. Bore has 0.006 taper from top to bottom and 0.002 egg shape but is within limits so I decided to resue the pistons not bore the block and rebearing it. Ordered king main and rod bearings. Std size. And perfect circle by mahle rings. 41548 part number says for 88-94 idi. But these rings are 3mm top 2mm second 3mm oil. My pistons are according to mahle who made them 5/64 5/64 7/64 rings. Mahle stopped making these 41547 part number, Hastings, sealed power, total seal all doesn't make a set to fit. They can come up with a top and second ring but no oil ring. International dealer says he can't look up ford engine stuff, ford place says it obsolete no old stock in the dealer net work. Anyone else run into this? Short of new pistons any suggestions? I did find a sealed power kit with a Molly faced top ring and cast second but oil ring is wrong that I could use but still no 4.110 7/64 oil rings I can find

 

[turbo elk]

Information I may need in the future.

 

[bbjordan]

The '88 7.3 pistons had the thinner top rings. They were the same as 6.9. I remember this because I took rings like you are removing and used them in my 6.9 redneck rebuild.

http://www.oilburners.net/forums/showthread.php?60592-Redneck-6-9-Rebuild-(don-t-try-this-at-home)

The newer pistons use the thicker top ring. I can't remember when they changed it, but someone on this site will know.

Sucks that you can't find them. You could always get new std. pistons with the newer rings. Or get a another set of rings with thick tops, and use the second set of seconds as top rings. Or find a old set from some .030 over pistons and custom fit the rings. That is what I did. Not the difficult with the proper tool. I used the hand crank ring filer. A little more control than the electric ones. Measure, file, measure, file. You get the hang of it. I'm VERY pleased with the redneck rebuild. I should do an update on it.

 

[riotwarrior]

Why not compare the oil ring scrapers thicknesses, if the same new to old just reuse the old spacer for the scrapers that makes the size? Just a thought????? I think I have this put in a way that makes sense

 

[76ford466]

I don't think I want to regap used oversized rings personally. For one the tension on the rings would be wrong since they would be squeezed in too far. I do have the ring filer in my tool box though. I guess I'm just being cheap but tring to avoid replacing $600 pistons and if I did May as we'll just have it rebored since they are the same cost for oversize. The guy I talked to at mahle who made the factory pistons in the 80s for them said it was a one year only piston. It's just my luck to end up with something like this. Must have wore the rings too fast is the reason for the change, because it's only got 138,000 miles on it and they are past tolerance. But a thinner ring does usually seal better and have less friction. Just look at the trend of the manufactures on ring thickness in newer truck and cars. I went from a 5/64 to a 1/16 in my 460 engine for compression rings.

 

[riotwarrior]

I don't think I want to regap used oversized rings personally. For one the tension on the rings would be wrong since they would be squeezed in too far. I do have the ring filer in my tool box though. I guess I'm just being cheap but tring to avoid replacing $600 pistons and if I did May as we'll just have it rebored since they are the same cost for oversize. The guy I talked to at mahle who made the factory pistons in the 80s for them said it was a one year only piston. It's just my luck to end up with something like this. Must have wore the rings too fast is the reason for the change, because it's only got 138,000 miles on it and they are past tolerance. But a thinner ring does usually seal better and have less friction. Just look at the trend of the manufactures on ring thickness in newer truck and cars. I went from a 5/64 to a 1/16 in my 460 engine for compression rings.

NO no that's not what I am saying...


Take OLD oil rings...measure the thickness of scrapers....

Take NEW oil rings...measure the thickness of scrapers...

If same...good.

Take OLD oil rings...measure the /\/\/\/\/\/\/ spacer

Take NEW oil rings....measure the /\/\/\/\//\ spacer

If OLD is thinner than new and would work with NEW scraper rings, use those scrapers with old spacers...is what I'm saying



so be like

NEWNEWNEWNEWNEW
OLDOLDOLDOLDOLDOLD
NEWNEWNEWNEWNEW

---------------------- NEW
/\/\/\/\/\/\/\/\/\/\/\/ OLD
---------------------- NEW

All stock bore just thinking way outside box if you can get compression rings that fit but not oil ones....

Does that make more sense? Not use over sized rings...



Al

 

[76ford466]

I was referring to bbjordans post, the oil ring I got has one outter piece and one inner piece not the standard 3 ring. After talking to a mechanic friend of mine with lots experience on these, his personal 6.9 has outlasted 3 trucks and at least 250,000. He says 0.006 taper is too much to bore it and put new pistons in it. Said he tried it before and never masts long before it's hard to start again. Book said 0.008 but he has been doing this stuff for like 40 years retired now though.

 

[76ford466]

Update. I had no luck on finding any rings at all. So I just decided to suck it up and bare block it and send it to be machined. Looking for new pistons and called Mahle and the actually had some 0.020 shorter pistons with hard anodising coating on them. In a 0.030 overbore. Not too bad of a price on them either. I think this will work better since im putting a turbo on it. Also i would like to retract my statement of 0.006 bore taper. My bore gague reads in 0.0005 (somtimes I dont read the fine print) and it only 0.003 taper. But rings was till shot as far as end gap.

 

[TahoeTom]

Can a 7.3 safely be bored out .030 oversize? The cylinder walls are pretty thin to begin with. Best to find out before buying pistons.

 

[76ford466]

I would think so they even make a 0.040 over piston for them. The man at the machine shop has been doing this for about 30 years he is a ford fan also. He never said anything about going 0.030 over being too much. I could be wrong though only real way is to sonic check it. You wold be loosing 0.015 on the walls.

 

[riotwarrior]

I"ve got a block here that's 040 however two cylinders are sleeved...the rest not..***???

I'd consider sleeving if going that route of boring ... or all new stock size pistons n rings...if bores measure out OK and within spec!

JM2CW