Block Crack repair

davem201m38 · Post by **davem201m38** » Wed Aug 16, 2006 1:57 am

OK I have to face facts, whilst in Belgium the problem I thought I'd fixed re-appeared.

1.
My engine block is cracked 3inches long, parallel with the top edge about 1 inch down behind the igniter.
This crack can be easily stiched and not a problem.

BUT.. I'm getting water in the oil (just a small amount) so I assume, at worst the block is cracked someplace internally. I wont know till I completly strip it this winter. Has anybody got any experience of getting cracks inside the engine fixed??? is it possible??

2. M38 blocks arn't that common over here. Is a later CJ block the same as the MC block. If worst came to worst I might be able to find a CJ block if it was compatable and could take all the M38 equipment. It might just be easier to find a complete CJ engine.

3. If absolute worst comes to worst M201 engines are available that are French and have been built at the French tax payers expence, but I don't want to take that route. However these (in detail) may be a gear cam driven MB engine.

Many thanks,
Dave.

Post by **wesk** » Wed Aug 16, 2006 7:42 am

1-depends on available access to the crack.

2-The only difference between a CJ and M38 block with casting numbers 641087 early, 641087 late or 804380 is the serial number stamped above the water pump. Once the block has been rebuilt and top decked several times this number will disappear which then makes it absolutely impossible to ascertain weather the block was military or civilian. So any casting 641087 or 804380 without a serial number can be used with impunity in your M38. Now if you want to match one of the three castings specifically to your year group/serail Mc jeep then just get the appropriate casting.

Post by **Ryan_Miller** » Wed Aug 16, 2006 6:13 pm

Dave,

Nothing is impossible. I would keep one eye open for a good block and after you tear down yours, you may find it is repaiarable.

Sorry to hear about your bad luck.

maeserik · Post by **maeserik** » Thu Aug 17, 2006 5:07 am

Hi dave, in the netherlands there is a good shop with rebuild engines, i do not know the price, a little mail to him can help ?
Maybe there are shops in UK to?

http://www.bramvanbuuren-jeeps.nl/

I think i leave my (engine) head on, no leaks and good performance.
We want to change it next winter just to inspect everything but opening and retightening can cause cracks ?

good luck in finding an engine !

Erik

davem201m38 · Post by **davem201m38** » Fri Aug 18, 2006 1:26 am

Thanks for the replies.
Sorry for not replying eariler but having returned from Ursel I have had a JCB in re-grading the hill I live on and I'm working all hours to keep just ahead of my builders who are building retaining walls etc. So far they have layed 13,000 bricks and poured 13 m. cubed of concrete, big job!!

Thanks to Eric and his family for making me so welcome (and the Duvel) in Ursel, I'll try and post some pics here . Out of 300 vehicles over the 3 days we had 2 of only 3 M38 jeeps, I think, please correct me if I'm wrong Eric.

Eric, got your message about the M38 turnbuckles on the top (bache?) I'll have a go at sorting it out.

Eric, also I checked out the link to the work shop in your post. Please could you ask them for a price for a rebuilt CJ short block

Anyway, the block .......
I've just had my first quote back for stiching the crack and decking (what we call skimmimg) the block.
Decking (skimming) block = £75 about $110 I guess
Skimming the head = £75
Stiching the known crack = £750 about $1100 I guess.
finding, testing and stitching internal crack (if poss) ???????????

I would love to keep the MC block with this jeep as though not original to the jeep they have been a unit for a long time. But it looks like I'm going to have to find a CJ block. So thanks Wes for the casting no. info as I now know what to look for.
One question Wes, does the little platform that the MC engine no is stamped on behind the water pump also occurr on the CJ engine, just so I can quickly differenciate the blocks on stalls etc. At Ursel there was a block sitting there but it lacked the boss for the MC no. so I assumed it wasn't CJ or MC.
Thanks,
Dave.

maeserik · Post by **maeserik** » Fri Aug 18, 2006 6:52 am

There was another M38, from the Netherlands but far from original, converted to 12 volt with civilian ignition, alternator.
The original gauges where replaced with modern ones, and there was made a cutout in the dash for a car stereo ! The whole jeep looks in good condition ! I think there were many mb and cj parts used !
I forgot to make a picture of it, maybe on the w&w side there will be a pic of it !

Erik

Post by **wesk** » Fri Aug 18, 2006 8:03 am

There are several serial placement arrangements. The WWII MB (casting 638632) had the serial pad on the right front side of the block behind the oil filter bracket. The early CJ's (casting 638632) had a small pad there but had the larger pad area above the water pump. The very early CJ (casting 641087) was the same as previous 638632. The 641087 castings used for the M38 had only a very small oval on the right front side and had the main serial pad above the water pump. Of the two later 641087 castings the one with 4 frost plugs on the right side are for engine serials up thru MC74419 or chassis serials MC23262 Feb 52 and with 2 frost plugs on the right side for the remaining M38 production. A 804380 casting was introduced at the very last of production and I have only seen one with a MC serial. The rest have had RMC serials so it is possible that a handfull of Jun/Jul 52 M38's had these castings.

davem201m38 · Post by **davem201m38** » Mon Aug 21, 2006 2:31 am

Good infomation Wes, thanks.
I'll just concentrate on getting her up and running again.

Now let me just confirm my understanding at the pres.

1. An MB engine has a slightly spaced out cylinder set up (compared to the MC) so will not be compatable with my MC crank etc.

2. If I can get a later CJ block it should take my crank.

3. The igniter drive gear on the cam is the same in these CJ engines

4. If I can get a quality rebuilt CJ short block I'm laughing!!

I will just explain that last one, there are a number of people offering rebuilt engines that have been simply thrown together and sprayed green.

Having priced machining costs, shells, pistons, a rebuilt short engine is probably available cheaper than I can rebuild one myself as I don't have the economy of scale.
Thanks,
Dave

Thanks,
Dave.

Post by **wesk** » Mon Aug 21, 2006 2:44 pm

davem201m38 wrote: 1. An MB engine has a slightly spaced out cylinder set up (compared to the MC) so will not be compatable with my MC crank etc.
I don't believe this is true. The cylinder head has a different combustion chamber arrangement but either crank should fit.

2. If I can get a later CJ block it should take my crank.

3. The igniter drive gear on the cam is the same in these CJ engines

The cam gear is different as is the oil pump gear. Chain drives must have their own matched pair and gear drives must have their own matched pair.

Since you are not locked into a MC block only then any of the available L134's will work. Just use the correct internals and oil pump gear with whichever block you end up with. The head, manifolds and accesories from your MC engine will bolt right up.