MF50 backhoe Perkins engine rebuild

Hammered

New User
Perkins AD4.203 engine. Pulled the head off thinking we had a blown head gasket. Yes it was popped between #1 and #2. Upon further inspection noticed that there was pitting and such from sitting before we got this machine.... no biggie but also noticed a couple of the dry sleeve top flanges were cracked and #2 liner had a crack vertically that appeared to have a drop or two of coolant seeping through.... supposed to be dry liner but at that point decided to rebuild complete engine.
 
So got the backhoe split engine out and stripped right down to the bare block except for the "dry" liners.... #1,2 and 3 I was able to lightly tap out with a small hammer and flat blade screwdriver.... (they shouldn't come out so easily???) And then it appears that #2 that had a long vertical crack in the liner, the parent bore in the block appears to have multiple vertical cracks from a couple inches to 3 or 4 inches in length.....
What could cause this? And is my block now scrap metal??

Thanks in advance for any and all help and advice!
 
The sleeves shouldn't come out that easy, and with the cracks in the parent bore (if it were my tractor) I'd get a different block (who knows where else the block is cracked). Just wonder if the block in the tractor had a non-stress block put in it (I think the 4.203 may have been made with stress, and non stress blocks).
 
Tractors like the MF165, the MF industrial 3165, MF industrial 50, etc the engine block is a "stress block" since it is used as the frame of the tractor. A non-stressed engine block is used where the engine is mounted into a frame like a car, truck, portable water pump, generator, etc. A stressed engine block is heavier, and stronger to take the loading that a frame would take. You can use a stress block in a non-stress block application, but you can't use a non-stress block in-place of a stressed block application.
 
Years ago neighbor's 6.354 Perkins started getting water in cylinders five and six, when I pulled the head I was surprised to find vertical cracks through both sleeve and block on those two cylinders. I wanted the owner to let me get a good used block at a salvage yard, local machine shop said they could repair the block with repair sleeves. The repair route was cheaper so we went with that. Never had any more trouble with that block, so the shop must have done a good job. If the old sleeves came out that easily I'll bet the engine had sleeves replaced before. Perkins original sleeves usually fit .001-.003 tight, service sleeves are .001 tight to .001 loose. The 354 with the cracked sleeves were the original the engine came with.
 
Machine shop prices are pretty high these days, I'd call machine shops for price estimates (magniflux the entire block for cracks, and resleeve it), and look around for a good block with no cracks.
 
This block would be "stressed" it is part of the frame of the backhoe... the oil pan weighs probably 50 lbs!. I sent the head away to get checked over already. I've read that there are chrome or cast sleeves available and they have a different top flange thickness.... this machine came from a county... i rebuilt the instant reverse transmission already and found signs of some shoddy work inside it.. which leads me to think the same for this engine...
If there were sleeves with different flange thickness I wonder if the wrong (smaller) ones were installed allowing them work up and down...
I have some calls to make with regards to repair or replace I suppose.
Thanks for the input!
 
I think most were steel sleeves with cast iron rings on the pistons. Just did my 65 last year and it had steel sleeves. If I remember right the sleeves had a real small lip on the top , maybe .050. The supplier sent me the wrong ones first and they were .125. Could be the other way around on the lip but they were steel sleeves for sure. If you have cracks in the block I would have it bored and sleeved only if I couldn't find a good used block. IMHO
 
Well I'm in Alberta and I called every wrecking yard in the province and could not find nether a complete engine nor a good block, I have only called 1 Saskatchewan wrecker with no luck.... May call more later... my machinist told me about $200 per hole to re sleeve it.... I may just have to take the block in to him to check it out and determine the best course of action.
 
So I know it's been a very long time since I used a micrometer but I measured up the crank journals and I don't know if I'm over thinking or not.... the spec is 2.249" on the rod
I measured it at 2.244"
Spec is 2.749 on the mains
I measured it at 2.744"

This perplexed me... perhaps I was over tired from cleaning parts in the varsol tank....
I searched the part numbers of the bearings that were in there and they seem to be standard size....
So I then plastigauged one of the con rods expecting to see excessive clearance... but it checks out ok.....
So I guess my question is, is the 0.005" difference something normal with an older well broken engine? There seems to be no such thing as a 5 thou undersize is there.... oh and the bearings that were in the engine had the Perkins stamp on them too.
 
The recommended clearance on the rod bearings should be .0025" - .004", are you checking the clearance with new bearings. The next size rod bearing is .010", of you got .005" with new bearings I'd get the rod journals turned down with some .010" bearings. Did you check your main bearing clearance yet, if not I would recommend it.
 
I have not ordered the rebuild kit yet. I just checked clearance with one con rod with the original bearings... it checked out in spec...
According to the part # on the bearings that were in the engine they are std Perkins.... but my question is why would it be that I'm measuring 0.005 under on all the journals, main and crank pins?

It all just seems odd to me... and when I'm building an engine I like things to make sense..... :lol:
 
I would check whatever you are using to measure the journals to see if its reading correct. Put say a .020" feeler gauge, and see what your measuring equipment measures.
 
I just took it into the machine shop where the block and head are... he mic' d it and it checks out standard size... so were all good and I'm out to lunch somehow.
Standard major overhaul kit on order!
 

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