New factory short block?

[Modman]

Okay! now there's some words of wisdom, magnaflux aluminium eh!! I have read this tread and did not find good confirmation of JB weld and the crack I beleive is from the current problem not a past catastrophy?? maybe the owner could expand on this??

???? Past history? The motor was welded like that when he bought it, with the big weld marks in the case. If you guys want to see an exact motor, just like this one, with the exact same problem, and the exact same fix, let me know and I will post video later.

Same thing happened to my pal, blew the con rod bearing, cracked the case, welded the case....looked identical to this one.....blew up the motor again about the same mileage later, rebuilt the top end, blew the motor a 3rd time and threw the whole sled in the trash. Midrange lean was the cause of the initial con rod failure from Deto as shockman suggests, but once the case is cracked you are fawked, there is no repairing it. I have never seen one come like that from Doo and if I did I would send it back to have it melted down and re-cast into toy cars because that's about all they are good for. Once the case is welded the heat and the stress cracks ruin any integrity the case had. If you got one from Doo like this with a factory "weld", you got ripped off and should have sent it back.

 

[calgarysledguy]

This was the bottom of the engine...

Are the piston skirts still on that damaged piston?

If the piston lost a skirt causing the cracks, that patch job probley would have popped out.Looks like the case was repaired .
I could see how a skirt getting jambed between the crank and case could cause the damage.Or a broken rod.But if there still on that piston then i find it hard to believe.

 

[imdoo'n]

something sure sounds fishy here. the case bottom is cracked, most likely new, my question why is the repair not broken? either barnes did this or someone else. mr r's would never let that engine out with that crack. those guys new there stuff.
to me that motor was run with leaking exhaust gaskets or worse. that is some thick oil coating. someone is not telling the story here. , i would like to see more pic. mr barnes you said you lent sled out, not able to ride? something sure smells funny to me.

anyone else.

 

[maxwell]

???? Past history? The motor was welded like that when he bought it, with the big weld marks in the case. If you guys want to see an exact motor, just like this one, with the exact same problem, and the exact same fix, let me know and I will post video later.

Same thing happened to my pal, blew the con rod bearing, cracked the case, welded the case....looked identical to this one.....blew up the motor again about the same mileage later, rebuilt the top end, blew the motor a 3rd time and threw the whole sled in the trash. Midrange lean was the cause of the initial con rod failure from Deto as shockman suggests, but once the case is cracked you are fawked, there is no repairing it. I have never seen one come like that from Doo and if I did I would send it back to have it melted down and re-cast into toy cars because that's about all they are good for. Once the case is welded the heat and the stress cracks ruin any integrity the case had. If you got one from Doo like this with a factory "weld", you got ripped off and should have sent it back.

have to agree here forsure. had many of shortblocks through the shop and never one repaired like this. BRP doesnt give you a core credit if you send them cases like this....so they are going to turn around and reuse them? doubtfull but im asking the question because i dont know the answer. but i havent seen it in my experience.

 

[tex78]

the exhaust leak was cause there was know gaskets between the head-y pipe.... thats what barne said

 

[imdoo'n]

yeah looks lie somene did a fast repair job, before anyone found out. smells real fishy. WTF.

 

[Modman]

Are the piston skirts still on that damaged piston?

If the piston lost a skirt causing the cracks, that patch job probley would have popped out.Looks like the case was repaired .
I could see how a skirt getting jambed between the crank and case could cause the damage.Or a broken rod.But if there still on that piston then i find it hard to believe.

Piston skirts are probably still there. These motors had a tendency to pop the con rod bearings. There is a small amount of clearance in the case from the bottom of the con rod to the case, not enough to fit a piston skirt even, if it did get jammed in there the motor would have stopped rotating completely because it would have wedged it tight.

What typically happens is the con rod bearing fails and the resulting play in the connecting rod and the crank, allows the bottom of the connecting rod to slam into the case but the motor still rotates. When this happens the case cracks and the motor will not run properly, mainly because it sounds like a 1930's diesel engine being started at 30 below (lots of banging and clanging from the rod hitting the case), and also because all the crankcase pressure is lost when the piston is on the downstroke (pressurizing the crankcase), and some of the air/fuel mixture is forced out the crack in the bottom and is displaced with raw air as the upstroke beings, the mixture volume is insufficient for combustion and also far too lean to run on and the cylinder does not ignite (on the side with the crack).

If the repair weld is poor then there is an air leak and you get to rebuild and try again. Its hard to achieve perfect weld penetration because there is no way to properly clean the weld without grinding out the crack (which is very hard to do without potential for changing the volume of the crankcase. Even applying something like JB weld is inadequate because the crack has still got oil in it so it might not fully adhere and also the case shrinks and expands as it heats, so even if the JB weld does adhere initially, it will not shrink and expand with the same thermal properties as the crankcase, and over time an air leak may develop anyway, which means another rebuild. The weld itself is also more prone to re-cracking or separation, because typically its thicker or thinner than the case material and may have impurities in the rod, which means it will not share the same thermal properties as the case either. Overtime with the repeated heated and cooling expansion/contraction cycles, it may re-crack or separate as well.

All these same reasons are why I would suspect Doo would not bother to repair cracked cases, its very likely cheaper to just re-cast and machine the part on a CNC mill using a computer, when you consider the human effort of cleaning the block, grinding the crack, welding, pressure testing the weld or x-raying, etc etc.

I've tried the welding thing on a couple motors and even when welded by Aerospace here in Calgary, who guarantees their work 100%, the motors still eventually went down again. As much as it sucks to say....cracked cases means a full shortblock replacement, or at least full case replacement with matching halves and crank (which are not that much cheaper than a shortblock).

 

[shockman]

OKAY! everybody is assuming that this case has been welded?? I, from the pics do not see proof of this, the small funny looking patch is quite common on these castings. I have personally had my own 700 with 20000+k on it do this twice and on one occasion cause a very small crack right at the centre of that area, which I beleive would be the only damage anyone would attempt to repair. When the thrust washer and needles come apart they usually cause the damage and also get through the transfer ports and damage the cylinder. However of the dozens I have seen do this there always appears to be deto signs on piston. I would be on ebay getting replacement cases and get a rebuilt crank from rec supply and weisco piston kit and hope your head is not too damaged, cheapest way out of this one!
Check nicasil for damage also as that's another couple hundy or ebay for a used one.

 

[shockman]

If that is a weld?? surely the owner could tell and say so?? however it does not mean it caused this failure, may have added to the size of the crack though.

 

[Modman]

OKAY! everybody is assuming that this case has been welded?? I, from the pics do not see proof of this, the small funny looking patch is quite common on these castings.....

The comments about the case being welded came from the guy who took the motor plate off and inspected it, obvious weld job.

...... now when we pulled the motor out there was a crap load of old RTV, which is suspicious, what they heck were they trying to patch with that. then we pulled off the engine mounting plate on the bottom of the engine and boom. crack city. what it looks like to me is someone zapped it with a TIG or something to fix a crack that was there before, but looks like the heat involved in that caused the rest. ......

I have seen casting rubs and motor plate rubs but if you think that the "rub" mark on the left side (PTO) of the crankcase is normal or that it was not welded, might be time for some glasses. It even looks like it has heat rings around it in the photo.

Someone here is lying and they know it - the dealer did not install a "new" shortblock, the seller mis-represented the sled when sold, or the buyer blew it up and is trying to pull a fast one.

Should be interesting when we find out which one........

 

[maxwell]

is it strange that the advertisement at the bottom of the page right now is for TETH AIR?

 

[Bogger]

The comments about the case being welded came from the guy who took the motor plate off and inspected it, obvious weld job.



I have seen casting rubs and motor plate rubs but if you think that the "rub" mark on the left side (PTO) of the crankcase is normal or that it was not welded, might be time for some glasses. It even looks like it has heat rings around it in the photo.

Someone here is lying and they know it - the dealer did not install a "new" shortblock, the seller mis-represented the sled when sold, or the buyer blew it up and is trying to pull a fast one.

Should be interesting when we find out which one........

Sounds like we need a poll...........

 

[teeroy]

looks like we have a mystery on our hands.....

 

[Mike270412]

Does Hawkins make Scoobie snacks?

looks like we have a mystery on our hands.....

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[shockman]

The comments about the case being welded came from the guy who took the motor plate off and inspected it, obvious weld job.



I have seen casting rubs and motor plate rubs but if you think that the "rub" mark on the left side (PTO) of the crankcase is normal or that it was not welded, might be time for some glasses. It even looks like it has heat rings around it in the photo.

Someone here is lying and they know it - the dealer did not install a "new" shortblock, the seller mis-represented the sled when sold, or the buyer blew it up and is trying to pull a fast one.

Should be interesting when we find out which one........

I tend to agree with you (with my 3pwr glasses on), I just doubt the guy who made the comment "looks like heat caused the crack" I think it's pretty obvious what caused the crack and it wasn't heat I doubt we'll find out who really knows what on this one?

 

[Mike270412]

Grisom would have this chit figured out between commercials!

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[Bogger]

Grisom would have this chit figured out between commercials!

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Is he a member on here???????

 

[Mike270412]

Have to get him signed up if he isn't. Him or Horatio

Is he a member on here???????

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[TABSTER]

someone is getting boned....seller and/or buyer...either way its a ch!t deal for both dudes....

Friggin ski-doo's

 

[maxwell]

for me personally genuine brp shortblocks have been amazing for reliability. got 2000+ miles and 30+ bottles of nitrous through one and its still within all specs