T-245 Engine Questions...

[HvyGunner]

I've got the engine stripped down as far as it can go without special tools, and, of course, I have a question:

1) The engine has cylinder sleeves, and they look pretty humble. Should I attempt to replace them, or send them in to a professional engine re-builder for this part of the process?

More questions to follow, I'm sure.

[MSeriesRebuild]

I've got the engine stripped down as far as it can go without special tools, and, of course, I have a question:

1) The engine has cylinder sleeves, and they look pretty humble. Should I attempt to replace them, or send them in to a professional engine re-builder for this part of the process?

More questions to follow, I'm sure.

Boring the sleeves is usually the best thing to do. That is of course provided the sleeve wall is thick enough after the cylinders are oversized enough to get back truly round. The maximum bore diameter is .060" over standard. Engines that have been sleeved will always run and perform better, that is just a fact.

[HvyGunner]

If the sleeves have been worn down or damaged, should a machine shop replace them? Should I be looking for a particular set of qualifications?

[MSeriesRebuild]

If the sleeves have been worn down or damaged, should a machine shop replace them? Should I be looking for a particular set of qualifications?

Only if it is necessary after checking things out. When a block has been sleeved, the usual reason why is as follows:

In most cases, sleeves are installed when cylinder wear is too great for a .060" oversize bore to clear up the damage. If this was the case, the cylinders were bored large enough to allow a sleeve to be pressed in, the interior sleeve bore would then be finished to bring the cylinder bore back to standard. This would have been done professionally. If the sleeves have never been bored larger than standard, depending on the wear that is now present; they should have walls thick enough to be oversized at least once and probably twice. The second time being for still another overhaul at some point down the road later. What I'm saying will have to be verified by measuring the cylinder bore diameters with precision measuring instruments. You will need to consult an engine machinist for proper measuring and checking to see how much out of round the cylinders are and to get the boring done to bring it to the next oversize that is enough to clear up any out of round condition. You will have to purchase oversized pistons and rings to fit the new bore. Piston and ring sets come in standard, .010" over, .020" over, .030" over, .040" over, and .060" over. Some of these sizes may be hard to find, if so then you must bore to a size that is available.

[m-11]

Charles,

After reading your response it has me thinking of my engine. I have a 1969 military rebuild and the data plate is stamped showing the bore, mains, and rods as standard. Did the military even bother sleeving the cylinders back than or is this more of a civilian practice? Can I safely assume, provided that no one has messed with the engine, that I have a virgin block? Right now I'm looking at doing a reseal instead of a rebuild. Of course that can change after I do a compression test and drop the oil pan.

Tim

[Lifer]

Did the military even bother sleeving the cylinders back than or is this more of a civilian practice?

I can't be certain about the M37, but I'm sure that many a military engine was sleeved in order to prolong its active life. During wartime, it would have been a virtual necessity, as replacement engines would have been very scarce.

[Carter]

The engine I rebuilt and used in my truck had a Letterkenny Army Depot (LEAD) rebuild tag indicating standard cyl. bore but had been sleeved by them back to standard and I have seen others that were sleeved but marked as overbored indicating more than one rebuild for that engine block by the depot

[m-11]

I guess that was what I was trying to ask in a round about way. So even though it's stamped as standard this could mean that it's back to standard because it was sleeved bore, correct?

[MSeriesRebuild]

Charles,

After reading your response it has me thinking of my engine. I have a 1969 military rebuild and the data plate is stamped showing the bore, mains, and rods as standard. Did the military even bother sleeving the cylinders back than or is this more of a civilian practice? Can I safely assume, provided that no one has messed with the engine, that I have a virgin block? Right now I'm looking at doing a reseal instead of a rebuild. Of course that can change after I do a compression test and drop the oil pan.

Tim

A compression test is a wise first step. The block may or may not have been sleeved, if mileage is significant, most likely it has if the bore is standard. Don't rely on the rebuild tag, I've seen many that were not bearing correct information.

[m-11]

Charles,

It's got 46300 on the odometer. Do you consider this low mileage?

Tim