Piston slap

Anola · Apr 21, 2019

Pull the head off on my lx865 3 cylinder diesel there is no score marks on the sleeves and not much of a ridge on the top of the sleeve but I have a lot of piston slap I actually think the piston is touching the sleeve when I move it from side to side as I here a noise as it were hitting smokeing and using a lot of oil is this piston slap normal or my rings wore that bad. Thanks any comments would greatly appreciate. Mike

David G · Apr 21, 2019

Rings do not cause piston slap, it is caused by excess clearance on the skirts.

shinnery · Apr 21, 2019

There is a process called "knerling" that some machine shops used to do to piston skirts to help them fit the cylinder bores. It will quiten the noise.

Anola · Apr 21, 2019

(reply to post at 19:19:22 04/21/19)

ank you for that information so I guess I would be looking at new pistons and rings would I be able to get by without changing the sleeves

Anola · Apr 21, 2019

Also would this cause the engine to use oil as that s why I pulled it apart.

Jim.ME · Apr 22, 2019

You say you have smoke, oil burning and piston slap. Your rings are likely worn out and allowing oil past them, along with piston and sleeve wear. The pistons' ring grooves and lands are likely worn as well. Its not a look and guess to say if they are fit to reuse to do it right. You are dealing with thousands of an inch differences between in spec and not. You need to measure the pistons and sleeves, with the proper instruments, to see where they are compared to the specs and then decide what needs to be rebuilt/replaced that way. If the sleeves measure within specs, and the pistons are close have them knurled to fit the sleeves and replace the rings. Otherwise replace the sleeves, pistons, and rings and be done with it. The head should be checked and reworked as well, the valve guides may be worn and allowing excess oil past them. JMHO.

David G · Apr 22, 2019

I have knurled pistons to reduce slap, would only do it if new parts were not available.

When a piston gets loose in the cylinder, it rocks back and forth. This rocking causes the rings to be unsquare in the cylinders and causes ring and groove wear. Rings are meant to be square in the cylinder with square edges to seal. Being unsquare also causes the end gap to increase, thus making sealing more of a problem.

Bottom line, I would replace pistons, rings and sleeves.

David G · Apr 22, 2019

As stated, the grooves must be square and tight also. The grooves tend to get tapered out on the outside, due to the twisting torque on the rings. The top groove usually wears the worst, and it is fairly easy to cut it square and install a spacer.

John Deere D · Apr 22, 2019

Anola....Do you own a service manual.....lx865 3 cylinder diesel????

Service manuals are inexpensive compared to $$$$$$$ mistakes:

I've been there done that (BTDT)

Bob.....Good luck Anola......

John Deere D · Apr 23, 2019

If you do not measure the I/D of the cylinder bores you may be wasting your money:

AJ. · Apr 23, 2019

It's a while since I seen one,piston noise is usually caused by the ridge on the top when the top ring touches it,if the engine is using oil and smoking then that speaks for itself,the engine is worn,what hours has it done or has it ever run low in oil,for the piston shirt to be touching the side it would not last long till it picked up and seized,I seem to think the engine did not have sleeves and had to be re-bored when worn,they done oversize pistons for it.
AJ

Anola · Apr 23, 2019

Thanks to all for this great information will be pulling out pistons today I don t mind replacing rings and pistons but I afraid the sleeves might be dry sleeves and they will be hard to remove what s the best way to get those suckers out. Thanks Mike

Jim.ME · Apr 23, 2019

As John Deere D (Bob) posted. Do you have a manual(s) for your machine and engine? If not, get one you are going to need it. You are going to need the specification info in it to do this right. Yes they cost money but it can be a lot less than the cost of a mistake. Do you have the tools to measure the wear and determine what is worn and how things compare to specs? The manual may give you the tooling info on pulling and installing the sleeves.

AJ. · Apr 23, 2019

I am fairly sure that it does not have sleeves,however they did what we call in the trade call a service sleeve which is a sleeve that could be put in should the block be damaged beyond the oversize piston,to fit the service sleeve the block would have to be bored out to take it,your best bet now is clean off the carbon around the top and remove the pistons,have a mechanic have a look at for you as he will know from experience what the best to do.
AJ

Anola · Apr 23, 2019

Pull the pistons found out no sleeves pistons skirts are hitting the cylinder wall what is worn out to cause this has I don t think anything should make contact except the rings

John Deere D · Apr 23, 2019

Check the I/D of all cylinders at six different positions...three on the MINOR plane and three on the MAJOR plane.

Check max I/D of cylinders. Verify serviceable limits as per service manual?????

Check O/D diameters of pistons.Verify serviceable limits as per service manual??????

Bob...

AJ. · Apr 24, 2019

If you got lots of diesel engines rebuilds under your belt you will know at a glance if the pistons and bores are serviceable,otherwise don't confuse normal ware to be a disaster,you can see why I ask about the hours?, did it run low in oil,has the fuel injection ever been an issue,bad injectors can wash the oil from the bores and cause excessive ware,what will the workload on this machine be,maybe you will get away with a set of rings and if you only use it occasionally it could last years,without going to the expense of buying expensive measuring tools and maybe having to learn how to use them the usual way to determine ware is use a new piston ring in the bore and check the gap when the ring is square bout half way down,if you want to recondition the engine and you can get a mobile re-boring service to do it in situ.
Good luck
AJ

Anola · Apr 24, 2019

Thanks to everything who help me with all this great info,have a service manual on the way will borrow instruments to measure just waiting to hear from the machine shop on the condition of the head. Again thank you. Mike

AJ. · Apr 24, 2019

Let the guy at the machine shop have a look at the pistons,he will know what to do,piston ring grooves can be repaired,recut etc.
AJ

Ozlander · May 5, 2019

(quoted from post at 18:33:10 04/23/19) Pull the pistons found out no sleeves pistons skirts are hitting the cylinder wall what is worn out to cause this has I don t think anything should make contact except the rings

It would be abnormal for the piston skirt not to touch the wall. There is no way to prevent it

Piston slap

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