Long shot:
Install the liner with Loctite Pipe Sealant with Teflon?
I suggest that because, even if the problem is actually corrosion and not fretting, the PST may prevent recurrence either way.
Long shot:
Install the liner with Loctite Pipe Sealant with Teflon?
I suggest that because, even if the problem is actually corrosion and not fretting, the PST may prevent recurrence either way.
Does the Loctite actuall eliminate fretting? I think it is fretting because it don't look like corrosion to me.
Fretting is a normal occurance in 71 series engines. I'm down to 3 in my fleet but I recently overhauled 2 of them. Both needed the blocks bored and oversized liners installed. One of the engines probably had in excess of 30k hours. Detroit specifies the liners be installed dry but I wonder if a bit of dry moly lube would prevent the fretting. It's no thing to have the block bored for oversized liners if it's easily removed for service but I can see how it would interfere with an in-frame overhaul.
Using Loctite retaining compound will certainly stop fretting as it's caused by movement but anything that interferes with the conduction of heat from the liners to the block will cause problems.
"Using Loctite retaining compound will certainly stop fretting as it's caused by movement but anything that interferes with the conduction of heat from the liners to the block will cause problems."
If that is to suggest the heat transfer will be worse with Loctite or even anti-seize compound or Kluber assembly paste, then across a dry interference fit metal-to-metal interface or even gap or fretted surface?
I have two 6L and one 4L engine. I'm not totally sure of their history. They had all been rebuilt once, one probably twice. The bearings and liners have date codes on them. Both blocks needed to be bored for the first time at the time I overhauled them.
I would be hesitant to use retaining compound. That makes the liner permanently a part of the block. If it expands at all while it cures it will also distort the cylinder. If you must do something I would start with a dry film lubricant like MoS2.
Do not use a high strength Loctite retaining compound. I would call them first and explain the application. I think
it maybe one of these to use 641, or 243. Let us know how it goes.
Proper cylinder block bore and liner OD are critical to proper service life, in my opinion putting something like locktite or pipe sealant on the OD of the liner is BAD, even a lubricant like molylube should be used with caution as you can affect to heat transfer between the liner and the bore, especially at the top end of the liner.
Two most important measurements for installing liners on these engines are,
Bore diameter, make sure clearence, surface finish, taper and ovality are within spec, and liner protrusion. Proper bore diameter assures proper liner support and heat transfer.
Proper liner protrusion assures the head properly holds the liner in place.
If you have fretting between the liner and the cylinder bore, you have movement during operation of those two parts. A properly overhauled engine with properly fitted liners will show very little or no liner to bore fretting come next teardown.
Here is a page with bore and liner dimension refereences,
Thanks for all the help you guys are beyond awesome. And a special thank you to you TugboatEng and Catserveeng. Tug you're a legend and I follow your posts all the time.
Any Detroit 2 stroke 71 and 53 I have taken apart the cylinder liners were always covered with oil, they are not press fit units.
And 71 series that I worked on where not wet 92 is. I would not go crazy with the Loctite. I don't think you would have any kind of movement at the top since clamping force and counter bore should take care of that. Any concern of heat rejection at the moving area the bottom of the liner should not present a problem. I asked about sizes at the start. I don't know what over size liner availability is, that should be checked before deciding the over bore, maybe that has been done a few times already. I suppose the block could be sleeved, though I have not seen that done.
