Repairing Aluminum

[AlanBartlett]

Repairing Aluminum Crankcases.

On the crankcase of my engine, Ive noticed that some of the lugs around the timing cover have cracked, some even snapped off. While Ive had the engine apart for other things, it would be an ideal chance to solve this. Would it be possible to weld to the brittle crankcase? Alu welding? Has anyone else experienced this over the years? What was their solutions?

[Chris Spencer]

Hi Alan - Alloys can be welded without issue - however, it is quite specialised - you need a TIG welder to undertake the welding - this is simular to MIG welding but uses different currents to create the weld arc - the filler rod is added manually much like you would with gas welding - TIG welding set ups can be expensive - so unless you have a large amount that requires welding and can obtain some value out the investment in the equipment required you are better taking it to a specialist welder.

Regards Chris

[Forumadmin]

Also it is important to prepare the item properly using stainless tools only used for aluminium work and heat up the item evenly in an oven. Then you do need a lot of skill. Often old Jowett aluminium is difficult to weld due to porisity and oxidization. Welding usually causes distortion so any machined surfaces will need checking.

Howvere saying all that I have successfully welded up the water jacket on a block with a MIG! But TIG is much better.

[Jack]

Repairing Aluminum Crankcases.

On the crankcase of my engine, Ive noticed that some of the lugs around the timing cover have cracked, some even snapped off. While Ive had the engine apart for other things, it would be an ideal chance to solve this. Would it be possible to weld to the brittle crankcase? Alu welding? Has anyone else experienced this over the years? What was their solutions?

The other thing to consider is the cost of a reaplacement crankcase from JCS (if they have one available) as it may be cheaper to do this than to have a specialist make the necessary repairs.

Of course you should keep your current one just in case for the future, as it is almost certainly repairable, but worth checking the cost of replacement before committing to a specialist spending a few hours working on your current one at workshop rates.

Perhaps one for the local section - there must be someone not far from you who has the necessary skills and expertise to assist with this job and who could be bribed with tea and biscuits?

Jack.

[Keith Andrews]

Im not too sure how well these old cases with such high Alumium content would weld up with our modern alloy sticks.
If going to get welded, ask if they have to pre heat the the whole item before welding...Cast Al is like cast iron, a very high heat expansion co efficient, and appling heat in certain small areas (depending on location) usually results in fractures in souranding areas.
The process, if done right is not complex, be it tig or mig.
U may find the best place to look is the local airfeild, a certified Aircraft welder.....which is what we use for small jobs welding cracked transmission case cracks etc... de grease , grind out , and finishing/dressing do yourself to keep their time down.

[Forumadmin]

The welder at Classic Autos matched the rods to the material in the block when he welded my cracked block (caused by a massive yump onto a carefully placed block of stone by a local Bedouin in Morrocco in 1988~) . Tell the welder the spec of the ally, it is in the technical notes.

[Tony Fearn]

...some of the lugs around the timing cover have cracked, some even snapped off.

Consider cleaning the area around the cracked lugs on the inside of the timing case, spray with clutch/brake cleaner to remove all oily deposits, and build up support using a modern two-pack metal-type Araldite behind the lug. If you are careful when tightening the nut, this might work.

The 'snapped-off' lugs will be very difficult to weld back on. They would have to be in the exact same position so that the studs married up with the holes in the timing case cover.

Perhaps a solution would be to drill new, smaller holes near to the snapped-off lugs through the timing case cover, into the aluminium of the timing case, and tapping the holes in the aluminium to take set screws.

This would ensure that the timing case cover was attached as it should be to the engine, and minimise oil leaks.

It could be done so that the set screw heads are almost invisible, and you could even glue a nut with a short length of bolt to the cover so that it looks original.

Tony.

[george garside]

I agree that Tony's suggestions may work and I have used industrial grade epoxy glue to join small broken off bits with complete success- the main requirement is absolute cleanliness of the joints which can be very difficult to achieve as can clamping odd shaped bits whilst curing .

another possible invisible 'bodge' could be to grind off the remainder of the snapped off lug and make up a similer size steel angle bracket bolting or rivetting one leg to the outside of the crankcase (ground flat to accomodate the bracket) and bolting the other leg to the timing cover as was with the lug. Alignment would not be a problem if the timing cover hole was drilled though the bracket in situ. Once in situ a dummy lug could be moulded over the angle bracket using aluminium flavour epoxy putty type stuff. I it wouldn't matter if the leg of the angle bracket bolted or rivetted to the outside of the timing case was longer ?deeper) then the original lug as the epoxy putty would more or less disguise it . Provided the bracket itself is sufficiently rigid it should only need one or maybe two small BA screw through the timing case as the load on them will be is shear rather than tension and the sideways pull will not be great as it is only to compress the gasket .

Please note that this is just an idea not a tried and tested method of repairing broken Jowett lugs (but I have used it to replace broken lugs on ''non Jowett' items.)

george