Piston Rings Worn Out, Time for a Rebuild

[rustystud]

So, in practical terms, what does the difference mean? The longer LDS arm will push the valve stem farther (open the valve more), with the push rod travel being the same? The cross section of the air passages does not change - what is the significance, other than perhaps a little less obstruction? A little better/quicker fill?

It's all about the volume of air allowed into the combustion chamber. Even though the valves are the same size, being open longer allows more air into the chamber. Like Mark was saying it is kinda like using a larger lobe cam without any cons for the lifters. The higher the lobe lift the more you damage flat tappets and the cams. That is why they actually went to roller lifters in the first place. So an engine using flat tappets can still get the benefits of a "higher lift cam" without actually having a higher lift cam by using different ratio rocker arms.

 

[gringeltaube]

That video does not look like blow-by it looks like water vapor.
Are you chasing the wrong problem?

 

[74M35A2]

It's likely blow-by. Compression is about 100psi lower than it is supposed to be, and it almost does not start. About 20 seconds of cranking before it lights off on a warm day. Even the pistons showed it by having carbon tracks past the top ring.

 

[mark salanco]

Here are some photos of the LDS rocker and the LDT rocker. You can see a big difference in the angle. The LDS rocker is angles in toward the center of the rocker arm shaft.

 

[mark salanco]

This video explains how rocker arm geometry can change lift and duration.

Watch "More Through Improved RoPowercker Arm Geometry" on YouTube
https://youtu.be/RjaosX63DkM

 

[74M35A2]

This video explains how rocker arm geometry can change lift and duration.

Watch "More Through Improved RoPowercker Arm Geometry" on YouTube
https://youtu.be/RjaosX63DkM

I was wondering where Colonel Sanders went...

 

[mark salanco]

Lol.

 

[74M35A2]

 

[Another Ahab]

I was wondering where Colonel Sanders went...

Yeah, but look at him; he's clearly cutting back on his biscuits and chicken:

- Maybe because he's been working too hard on those small blocks.

 

[mark salanco]

I did install the new LDS sleeves in the block Sunday. The biggest deviation I had on the sleeve to deck surface was 0.001, I'm confident the heads will seal properly.

 

[Wildchild467]

I went and got a "new" engine from Gimpy last weekend. I am very happy with it so far even though I did not swap it over yet. I noticed it had the old style head gaskets with the tabs that stick out of the block. I bought head gaskets gimp just in case I wanted to change them. So, here are my thoughts. I have all of the parts I need to put new rings in this engine... but should I? Then it would be completely fresh. I'm just nervous because I didn't have good luck with the LDS piston kits... would I be any better with honing these cylinders and putting new rings in? I guess if I did put rings in it, and do my same exact break in process, we all would know that the LDS piston kits I bought were junk from the start.

Tonight I removed the oil cooler assembly and installed one I bought before from a White 2-135 Farm Tractor. These are factory spin on oil filters... no more adapters!

 

[74M35A2]

I don't think you should touch the replacement engine. Look how the last one (2) turned out. Plus, we'd be at 120 pages of Oh No's....

 

[o1951]

I went and got a "new" engine from Gimpy last weekend. I am very happy with it so far even though I did not swap it over yet. I noticed it had the old style head gaskets with the tabs that stick out of the block. I bought head gaskets gimp just in case I wanted to change them. So, here are my thoughts. I have all of the parts I need to put new rings in this engine... but should I? Then it would be completely fresh. I'm just nervous because I didn't have good luck with the LDS piston kits... would I be any better with honing these cylinders and putting new rings in? I guess if I did put rings in it, and do my same exact break in process, we all would know that the LDS piston kits I bought were junk from the start.

Tonight I removed the oil cooler assembly and installed one I bought before from a White 2-135 Farm Tractor. These are factory spin on oil filters... no more adapters!

What did Gimpy say about the engine? If he says it is ok, you should leave it alone.

PS- just putting new rings in does not make the engine "completely fresh". Still has old valves, cam, tappets, oil pump... If I were putting new rings in, I would have the heads done, depending on how the cooling passages looked, have everything hot tanked.

 

[Wildchild467]

Gimp said it was a good running engine, and I do believe him. I am very happy with the engine I bought from him, so its not that I don't like the deal. I still have NOS heads on my old engine I could put on this engine. Those NOS heads I bought only have about 2000 miles on them. Chances are I would just use the heads that are on the engine now. Its easier that way. Ill still keep my old engine for parts.

 

[o1951]

repeat - If he says it is ok, you should leave it alone. I trust the Gimp. He knows what he is doing.

 

[daytonatrbo]

Tonight I removed the oil cooler assembly and installed one I bought before from a White 2-135 Farm Tractor. These are factory spin on oil filters... no more adapters!

Source?

 

[74M35A2]

Install it as-is, crank it up, and see what you've got as a baseline to begin with. If it runs well, then close the hood and drive it. You can monkey with it later once it is in the truck and requires it. It is kinf of hard to safely work on a medium size engine or larger without the correct engine stand. You can do almost everything with it once in the truck. Plus, once in the truck, you may as well crank it up as is just to see what you have. It may be just fine, and you're done. Hopefully it lasts more than 50,000 miles? That didn't sound very medium-duty. Light duty Honda Civic goes further than that before developing blow-by.

 

[mark salanco]

Gimp said it was a good running engine, and I do believe him. I am very happy with the engine I bought from him, so its not that I don't like the deal. I still have NOS heads on my old engine I could put on this engine. Those NOS heads I bought only have about 2000 miles on them. Chances are I would just use the heads that are on the engine now. Its easier that way. Ill still keep my old engine for parts.

It's great to hear that you have another engine.

 

[mark salanco]

I got my heads back from the shop today. It was $430 to get them cleaned, checked for cracks, surfaced, valve job and new guides installed. Will start getting the engine back together tomorrow.

 

[mikey]

I feel like you'd be cutting a hole in a new pair of jeans to patch a hole in an old pair.

If it aint broke, don't fix it.

I was following this thread for quite some time until maybe the last 8 pages. Did I miss a post? Did you find out, without a doubt, what was wrong with the current engine? If not, then that's ALL the more reason to leave this one alone. I think you deserve more time behind the wheel and less time behind the wrench at this point.

BTW, your name came up at RC this weekend. It's been quite a while. I hope life is good for you in MI.

Mikey