I had previously posted about a knocking engine and found it to be a piston skirt tearin up the cylinder.

Well The engine on my 03 is down to just the crank and cam. I'm gonna have the #6 cylinder bored over .20 or .40 (until the scuff comes out) and have the other 5 cyl. honed. Then I'm gonna get 1 new piston and all new rings. I took my pistons to a reputable engine builder (not the one I was gonna use) and he says that my rings are so bad that he would say I was losing 1/3 of my power to blow by.

A few questions:
#1 do I just pull he cam and crank and not worry about marking anything? I assume, But wanna make sure. I was planning on rolling engine over to pull cam. How hard are the tappets to put back in?

#2 while the engine is out and torn down...what else should I look at/change? Without wasting money

#3 Is there an easy way to lower compression ? I was thinking thicker gasket, but my guy says that won't do much at all.

#4 IS there any online re assembly notes/pics that I can use. Cummins wants alot for their book and I am putting enough $$ into the truck as is, and the library doesn't have any detailed books.

#5 ALSO.... If the rings are that worn...Wouldn't the pistons be worn at the grooves also ??

 

4. Get the Dodge FSM or a aftermarket manual.
3. Don't think lowering compression is good ideal either.
1. Keep tappets in same position. They are mushroom lifters and have to be pulled and held up to get cam out.
Believe I suggested the one cyl overbore. Told you rings worn out also.
Oh yes, Keep it clean!!!!!
Anyway! good luck on rebuild.

 

I've never put an engine back together without a new oil pump.

Cya

 

my block is also bare I am going to have my pistons fly cut, a new cam and dual coil valve springs. also have you priced compression rings yet?? better sit down when you order them bad boys. also ask your engine builder what torque he is going to put on the rod bolts for me please. manual says 30,60 and then a 60 degree turn???

 

one thing i see wrong is over boring one cyl is not going to work if you dont over bore the rest. you can't have differant size pistons

 

you can't have differant size pistons


As long as pistons weight approx equal it works and pistons suposedlly weigh the same. You said it won't, now tell why in scientific terms, not some old tech tale?

 

I would assume cause it will have different compression due to its larger volume on the last cylinder.

 

I doubt your piston rings are bad, the Keystone rings on these engines will go a half a million miles, and even when they lose they're own tension, compression pushes them against the cylinder to seal compression. Also, who is this guy building your engine? Lowering compression can be good if you plan to really build up this engine, and a thicker gasket will lower it slightly, having the pistons cut will make a much more dramatic difference, but you'll need to match injectors to them later, since they won't hit the bowl the same. And yes, if the rings are worn that bad, the lands on the pistons would be worn too... but ask to see a ring, I doubt their bad.

I would definitely plan on heavier valve springs, and a set of head studs, if you plan on going wild, its a good time to replace or regrind the cam. You might want to look at the soft plug prevention kit, all I know about them is that its a PITA to install it when the engine is in the truck. I'd definitely get a manual, its well worth the money just for the torque readings alone.

Good luck, and let us know how it goes.

 

I am the one that pulled the engine..So I have all the parts. The rings have sharp edges on them from riding in the piston groove and they are sloppy as all heck in the grooves. If you take the piston and shake it, SOME of them actually work their way out of the groove. I am assuming that this is not normal.

As for the compression thing, I am on a tight budget and not looking to work the pistons. I was just asking an opinion on the gasket. ALSO...my guy says that if you cut the top of the piston down it will lead to the top ring getting too much heat ?????


I have not priced just the rings yet, but when I was looking up a rebuild kit (pistons, rings, bearings, gaskets) I could get them for under 1,000.

As for the oil pump...Both guys say to take it out, check it out, and if it looks good put it back in. The oil pump is the most spoiled in the system.

 

YOu said rings had 5/16" gap and assumed knew how to check. Ring wear measued by inserting ring in cyl and measuring end gap. It should be less than .027" for top ring and .021" for others. Square ring in bore by using piston to push ring down in bore 1/2 inch or so.
Top ring is a Keystone ring meaning not square. It will have some movement in ring groove. See Manual for checking procedure on piston groove wear.
Sounds like your engine builder is a gas engine builder.

 

Dozer is right, the top keystone should be loose, and your engine builder doesn't know what he's doing with a diesel, at least not a good diesel, I wouldn't mind him working on an old 6.2 though. The rings are supposed to have spring outwards, and not be tight to the ring land in the piston, if it was, you'd have blow by up the wazoo. If you don't know what your doing building a diesel, you can do a lot more harm than good, I can rebuild a small block in a few hours, but I won't touch a real diesel.

 

I did put the ring in, but i was just approximating. I will get the needed tools and get a good idea monday. Thanks for the heads up.