Technical Cracked block

[paul in manche]

Done a bit more dismantling of the spare engine this morning, and whilst undoing the big end bearings on the piston nearest the clutch end I noticed that the block is cracked between the crank and the sump.
Am I correct in thinking that this renders it useless or is there some repair method?

 

[Bleeding Knuckles]

Hi Paul, A crack in that area suggests that the engine has been stressed and possibly subject to high revs. Alloy parts can be repaired and welded as in the known cracks that appear between valves in some cylinder heads. Take it to your local engineer shop and ask them if they can do a repair. I would check carefully that you don't have other cracks from the bearing mounting - your engineer should be able to do a simple fluid crack check that will show up even minor cracks, check the other bearing mount area too.
Ian.

 

[the hobbler]

Done a bit more dismantling of the spare engine this morning, and whilst undoing the big end bearings on the piston nearest the clutch end I noticed that the block is cracked between the crank and the sump.
Am I correct in thinking that this renders it useless or is there some repair method?

Hi Paul;
I second Ian's suggestion of taking the crankcase to an engineer and getting them to give it a thorough check-over. I have never seen such damage as you describe, and would put it down to the engine possibly being re-built after a major 'blow-up' I have suffered a snapped crankshaft (caused by er, excessive revs!---my own fault) and the crankcase was undamaged---they are tough engines.

 

[Bounding Bambino]

Most engine block casting are not the best quality for welding. Aluminum welding can be very difficult on cast parts due to the "loose" material composition on sand castings.. With that said, my engine block had a crack with a very "pathetic" attempt at a repair.
After removing all the contamination, end drilling the crack, i was able to completely build up the case and repair it. The aluminum composition on the casting was actually very good quality; very mild porosity, and i suppose fiat had some decent material specs for the day.

The key is, to ensure it is clean. Castings that have been exposed to oils are super hard to weld, especially when Tig welding. But it is possible.

Ive done some repairs on tough materials in the past, but the fiat castings were definitely in my top percentile of decent repair-ability.

 

[the hobbler]

Most engine block casting are not the best quality for welding. Aluminum welding can be very difficult on cast parts due to the "loose" material composition on sand castings.. With that said, my engine block had a crack with a very "pathetic" attempt at a repair.
After removing all the contamination, end drilling the crack, i was able to completely build up the case and repair it. The aluminum composition on the casting was actually very good quality; very mild porosity, and i suppose fiat had some decent material specs for the day.

The key is, to ensure it is clean. Castings that have been exposed to oils are super hard to weld, especially when Tig welding. But it is possible.

Ive done some repairs on tough materials in the past, but the fiat castings were definitely in my top percentile of decent repair-ability.

Totally agree with you Jacques---everybody thinks of the 500 as a 'cheap' car. Cost-wise it was, but Fiat used good quality materials to make them from; it is only the 'pattern' parts which are crap quality and (in some cases) crap fitment.

 

[paul in manche]

I first noticed the crack after taking the sump off - there was a line across the casting and a definite 'step' between the part immediately under the crank and the rest of the casting, so I suspect that the hole that the crank runs in is now no longer circular.
Fortunately its only a 'spare', so I'll strip it right out, keep all the components and park it all in the loft of the garage.
Might start getting the one out of the car later on. When we bought it the previous owner described the clutch as being a 'bit fierce' and in need of changing.
The crack in the block of the spare means its on to plan B, remove engine, inspect, titivate the inside of the engine bay and hopefully all will be well, fingers crossed.

 

[Bounding Bambino]

If you can post a photo, i would be courious to see how this one looks, and how it propagated. For curiosity sake. lol

 

[paul in manche]

Will try and take photo tomorrow....
I've got the other one dismantled now, more or less completely stripped down, only a couple of problems!
Can't get the distributor housing out, it looks well stuck..
Trying to get the bungs out of the oil gallery as the inside of the engine seems to have quite a build up of fairly hard muck inside it, so far got one out, but the others seem to be about as hard as the sort of cheese you put on pasta - the allen sockets have already rounded off, so plenty of swearing at them this afternoon!

 

[the hobbler]

If you can post a photo, i would be courious to see how this one looks, and how it propagated. For curiosity sake. lol

The trick for removing the threaded 'core-plugs' is to hammer in an IMPERIAL sized allen key (which will be slightly bigger) as the ally of the plugs is very soft---a bit of heat MIGHT help.

 

[paul in manche]

I had a feeling it might involve violence, I'll have a rummage through my stock of hammers and blunt instruments. Fortunately my stock of gas canisters for the blowlamp is good!

 

[paul in manche]

A 3/8 drive size 50 torx bit, smallish hammer and heat did the trick, oddly enough underneath the bung inside the block near the distributor drive had what looked like new petroleum jelly inside it, although the blow lamp soon boiled that off!
A couple of cans of brake cleaner got rid of the worst of the muck, just as well I buy it by the boxfull!