Crank pulley replacement

I asked a similar question a few months ago and it went nowhere, so trying again.

I have a manual steering Mk2 and am installing a 4.2 from a 1965 MkX. The 4.2 used v-belts, not double-groove/W-belts. I want to add AC.

My crankshaft pulley has a big chip missing so should probably be replaced. I want to add AC. No PS. New pulleys are only available as W-belt/double groove as far as I can tell. I’ve found crank pulleys on ebay, but they are equally sized (about 5 inches) and mine are 2 different sizes (about 6.5 and 5 inches, respectively). Can I use a 5 inch pulley with equal size pulleys?

I have attached pics of mine and pics from an E-type thread on cars with AC and no PS. The unequal size pulleys were on a S2 XJ6


If you can use the pulley why not weld (or have it welded) and ground down to the original profile.

I can’t see why you couldn’t use the 2 - 5” pulleys just one or more of the ancillaries will be being under driven.

I am going to say yes, as I added an A/C pulley to my 420G,

I used XJ parts. So long as everything lines up and bolts up you should have no worries

The pulley size only dictates the belt speed, which I dont think is critical for A/C

I was also lucky that in my parts collection, I had various brackets, York compressors and associated parts, the best find being an OEM tensioner assembly with 2 adjustable arms, and original York compressor bracket

In fact I overhauled my York and installed it, but switched to a Sanden 7 series,
you can buy a Sanden to York bracket for about $50

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If you smooth the inner edges of that chip on your pulley, you can probably use it just fine. I had one on Tweety like that for a long time and it didn’t affect the belt.

I think most Crank pulley’s are interchangeable , only diffrence is the location of the timing mark’s , as the keyway is in a diffrent place the pointer will be, early XK engines its at the bottom , later its on the right hand side ,

Thanks for the replies. I know it’s not that big, but a missing chip like that won’t affect balance?

Small rotating diametre would not have a noticeable effect on balance.

No. I would be more concerned with it tearing up the belt. Again, pretty easy to just have it filled with weld material and grind it off smooth.

As Robin said, even if you didn’t fill it, it would have a next to nothing effect on balance.

I just filed one nice and smooth on the inside, didnt weld up, the nick was maybe 1/8" at most, it was just a ding, not a crack

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Worth trying JB weld on it , that is very strong !
Once painted your never know a chip was there .

I agree. That’s what I’d do.

It’s cast iron so I doubt you could do a weld repair successfully.

If you were really concerned you could get it crack tested.

You need a pulley setup like this?

That looks like it might be the same one.

Do you need just the one pulley or a set? I have spares.

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Thanks, Tim. The consensus seems to be that I can use this one, so I’ll give it a shot. You’ll be the first person I contact if it does not!

Now you’re talking Ian! I dropped my Mk2’s pulley onto the trolley jack and chipped out a decent lump of cast iron. This was six years ago just after I’d bought it with a known doughy lower chain. I JB Welded it and it’s still sound. The other way to do such a repair is to braze it.

This engine came with a chipped pulley. There was nothing to glue or braze back on! :slight_smile:

You build up the missing part with JB weld and rub it down , bit like body filler !!