WARNING!!! Rebuilding GPW/MB Engines

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Joe Gopan » Tue Mar 06, 2018 10:08 am

This is a good topic and a good mix of technical advice from both experienced and non experienced. There is always going to be good and not so good advice to be had. The not so good advice will speak for itself to those who choose to try it.
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Tue Mar 06, 2018 10:36 am

Ben Dover wrote:
Tue Mar 06, 2018 10:08 am
This is a good topic and a good mix of technical advice from both experienced and non experienced. There is always going to be good and not so good advice to be had. The not so good advice will speak for itself to those who choose to try it.
Agreed, But no need to drag out the same topic for 4 pages, don't you think :wink:

THere are probably several more aspects not yet covered
Oz

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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Tue Mar 06, 2018 10:46 am

bantamj wrote:
Tue Mar 06, 2018 10:38 am
Yep, back to the good things in life!
Another one when installing new liners.
Make sure they are not too long.

Best Regards,
Luc
Do you mean new cylinder sleeves? They stick out the bottom too far?

thanks in advance
Oz

Feb 43 GPW 98532 USA 20206257
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Tue Mar 06, 2018 11:04 am

Excellent...thanks
Oz

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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Joe Gopan » Tue Mar 06, 2018 11:45 am

The Sleeves I have used since the 60's are for a Bore Diameter (3.3125") and have a finished Outside Diameter of 3.3155". The "Bored Diameter is the bore that is cut to match the O.D. of the sleeve prior to pressing in the sleeve. The Particular Brand Sleeve I kept on hand was TRW SL 349F, the length of the sleeve came precut to match the cylinder bore of the Willys 134 Block and did not need to be trimed. These Sleeves are Chamfered on the bottom I.D and Square Cut on the top, and pressed in even with the deck of the block.
Some Sleeving operations in other make blocks do need to be altered at the bottom to clear the rods or other components, but not the TRW and the sealed Power Brand that are made to fit Jeep.
And remember, the sleeves are then bored to fit the size pistons that will be installed.
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Tue Mar 06, 2018 11:49 am

If I am reading this correct, is that a 0.003" over sided pressed fit. I'm just a bit confused.
Oz

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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Joe Gopan » Tue Mar 06, 2018 11:51 am

17thAirborne wrote:
Tue Mar 06, 2018 10:36 am
Ben Dover wrote:
Tue Mar 06, 2018 10:08 am
This is a good topic and a good mix of technical advice from both experienced and non experienced. There is always going to be good and not so good advice to be had. The not so good advice will speak for itself to those who choose to try it.
Agreed, But no need to drag out the same topic for 4 pages, don't you think :wink:

THere are probably several more aspects not yet covered
Gotta remind you that those sharing experience are not paid for the time or cost incurred in sharing Jeep maintenance.
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LIFE MEMBER AM LEGION-40/8-DAV
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Tue Mar 06, 2018 12:02 pm

Ben Dover wrote:
Tue Mar 06, 2018 11:51 am

Gotta remind you that those sharing experience are not paid for the time or cost incurred in sharing Jeep maintenance.
No need to remind me of that. That is the purpose of a forum, to share information. Even though I have little experience in restorations, I have dedicated hundreds of hours of images, scans and my success and failures of restoring one vehicle so that others might learn from my trials and errors (guided by others). I do it not for my glory, but so that some one who is where I was can benefit from the work and errors I made. You probably have seen the work and documentation here:

viewtopic.php?f=56&t=277716

I did not get paid either, but then again no one forced me to make any posts either. Did it just because that's what we do! :)

Please do not get me wrong, I sincerely appreciate everyone who adds to the common knowledge in a forthright way. I would not be so far along in my resto if it weren't for others like yourself.
Oz

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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Tue Mar 06, 2018 12:28 pm

That is almost paper thin at the top part of the image :shock:
Oz

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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Joe Gopan » Tue Mar 06, 2018 2:30 pm

One small tidbit, the type sleeves I described are known as Dry Sleeves and are the only type I have witnessed used in Jeep blocks here in the USA. Most of you will never be installing your own sleeves due to the equipment and tools needed to perform sleeving and boring.
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Joe Gopan » Sun Mar 18, 2018 4:09 am

It's amazing how many Jeep engine rebuilds have a 100% success story when done by those with even a little experience.
The sky is not falling yet, and don't be afraid to ask questions when you are not sure.
One thing is for sure tho, as these Jeeps age closer toward the century mark, there will be flaws discovered in the engines that were never envisioned before grandfather time took its' toll. Thanks to technicians such as Luc who perform machine shop magic, these tired old Jeeps will run a few more happy miles.
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by 17thAirborne » Sun Mar 18, 2018 6:09 am

Ben Dover wrote:
Sun Mar 18, 2018 4:09 am
It's amazing how many Jeep engine rebuilds have a 100% success story when done by those with even a little experience.
The sky is not falling yet, and don't be afraid to ask questions when you are not sure.
One thing is for sure tho, as these Jeeps age closer toward the century mark, there will be flaws discovered in the engines that were never envisioned before grandfather time took its' toll. Thanks to technicians such as Luc who perform machine shop magic, these tired old Jeeps will run a few more happy miles.
...and that is why I started this thread. Will be tackling the rebuild and wanted to know all of those little hidden gems of info that aren't in the manuals. I'd rather learn from you guys than by trial and error any day. Gets expensive too. Thanks
Oz

Feb 43 GPW 98532 USA 20206257
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by KiwiMB » Sun Mar 18, 2018 11:56 am

By way of explanation, there are (Generally)two types of engine sleeves, wet and dry. Both are completely different animals:
The wet sleeved engines have very different cylinder designs with sealing mechanisms between the sleeve (more commonly known as liners) and cylinder block to prevent coolant leakage into the oil pan and under the cylinder head(s). The liner is in direct contact with the engine coolant, has machined areas that will mate with the lower liner seals, and a flanged top that fits into a counterbore in the top of the cylinder block. The counterbore is designed to accept shims or crush seals, these ensure each sleeve is the correct height above or below the cylinder block face to both effectively retain the liner and to ensure an efficient seal by the head gaskets.

Dry sleeves or liners can be a press fit or sliding fit (Bedford GM in the UK ) into the cylinder block and have no contact with the coolant. They are generally flangeless and only have a slight bevel on the outer lower edge to ease installation.

The sleeves being discussed here are a different beast in that they are intended as a press fit into the cylinder block that requires the parent bore to be machined way past what would be accepted as "normal" and once the sleeves are installed they become a replacement "parent bore". They are a considered to be a permanent repair for a worn on damaged cylinder block. I have had a number of Jeep engines sleeved over the years with very good outcomes.

Cheers

Ian
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Wolfman » Mon Mar 19, 2018 5:32 am

Here is one more for you OZ.
I agree with Ian and to take what he said a little further.
The repair sleeves used in L-134 engines are straight sleeves. By that, I mean they are smooth on the outside diameter. Their fit in the block is the only thing holding them in place.
When boring the block to install the sleeves, I have the machine shop leave a step at the bottom of the cylinder being bored so when the repair sleeve is being pressed into place, it comes up solid, at the bottom, against the step.
If the block is bored all the way through, there is nothing to keep the repair sleeve, under abnormal conditions like over heating, from coming loose and slipping down into the crankcase. Once it slips down, the top piston ring can pop out over the top of the repair sleeve, dragging the sleeve down into the crankcase. Show is over !!
The "step" will prevent this and once the engine cools back down and everything tightens back up, life will be good. You will never know there was an issue.
Your machinist may already know this, but it is a nice conversation to have with him. :wink:
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Re: WARNING!!! Rebuilding GPW/MB Engines

Post by Joe Gopan » Mon Mar 19, 2018 6:03 am

The Sleeves Specified in the various Sealed Power, etc Engine Parts Books come with instructions indicating bore size in preparing the block which results in a press fit for the new cylinder. They stay in place due to the pre determined tolerences. Have never seen a Jeep Sleeve move.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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