Timing cover corrosion

I was about to take my block to the machine shop and realized there is some pretty bad pitting in the water pump area. The rest of the cover looks good. How bad is bad though? Can it be welded? Leave it alone? I can get another timing cover, but I don’t want to have to deck the block down to meet a timing cover if it came from an engine that had already been decked.

I would grind out the pits, media blast the corrosion products and then keep a proper antifreeze mixture in it to protect against further corrosion.

Bad is too bad when it’s starting to get close to merging cavities. You can fix this in two ways, blast or grind clean and weld, then mill flat, or grind clean and use JB weld and mill flat. The problem with the first is expense if you aren’t a welder. The problem with the second method is that it’s possible the JB could break free and go flying into your radiator. JB works best when it’s sandwiched between two parts. I would attend to the deepest cavities at a minimum because they risk breaking through and are altering the flow characteristics and likely accelerating erosion. Slight roughness isn’t a deal breaker. Deep caverns are.

measure the depth of the ground out pits compared to the timing cover wall thickness

If that distance was 50% or over, I would not re-use them

That 50% is just my personal estimated max, I think most people would want a more conservative figure

How did the car cool whilst running? I’m imagining that the impeller on the current pump is a bit - compromised? A new pump, if that’s what you’re intending, might tighten the clearances and improve efficiency? I’m inclined to try a new pump and see how you go IF it was cooling previously.

A brand new timing cover shouldn’t be much more than the cost of welding/machining.
Or you could save a bit by buying a good used one.
Either way, I’d replace it.

There. Five responses and nearly as many opinions. From the “left field” when I was a cadet we were able to solder aluminium cables together and even aluminium to copper. Aluminium soldering has come a long way, as I understand it. I am going to try it myself sometime soon. Apparently much like copper soldering but given aluminium oxides re-present almost immediately after cleaning there are a few more issues. Fluxes and rods exist. If it were mine I guess I would try it expecting the worst, then get another.

Thanks all. This engine wasn’t running when I bought it. It turned out that the head internal passages were too corroded to use, so a corroded timing cover doesn’t surprise me. A new water pump is almost always in the cards for me when building an engine.

I had this happen on a S11 e type. I had a pin hole right thru into the timing gear, I could hear the water trickling into the sump.
I had it welded, twice, and they had to clamp it down for fear of warping.
I strongly suggest a good replacement. Measure the bad one top to bottom and see what you can find out there.

EBay seems to have used timing covers ranging between $100 and $150.

65 Mk2

That’s what I’d do. Easy fix now. Not so much once the car’s running and there’s a problem.

Note that the timing cover for the XJ6 has a different shape water hole (not rectangular, it has extra ears) and this might not be compatible with your block.

I use JB Weld on deep pits in alloy !
Don’t forget if you buy another , 2.4 are diffrent size to 3.4 and 3.8 !

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I have this one for sale in the UK 2.4 / 240 C8653
Looks like the water pump may have rubbed it , but not in the last 40 years , as it has been in my shed , next to no pitting
On e-bay £39 ,
£30 inc post in the UK to anyone on here !

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