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16H tappet guides

Submitted by david_cooper on Sat, 18/08/2018
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I find to my dismay that my (super-reliable until now) 16H inlet tappet can be rocked sideways a lot more than I expected. Looks like tappet guide?

The WD manual just says they are phosphor bronze and screwed into the crank case. But it doesn't say how. Am I right in supposing that they screw in from below, so it's a full engine strip? And I'll need a 1/4" reamer.

I don't yet know if they are available. Previous conversation here says they weren't easy to find a few years ago. I have a spare (rather rough) engine which might have an OK guide...maybe.

Any advice would be welcome. I could carry on using it I suppose, but I imagine it will get noisier and leakier quite quickly?

Thanks

David

Submitted by richard_payne on Sat, 18/08/2018

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You can indeed do them from above, David. The tappets just drop in so can be removed. Nothing below can go anywhere or get out of synch.

After high mileage, there is often a lot of half-burnt carbon and oil crud in the wells around the guides as the drain at the rear only works partially. It's certainly worth making sure everything is very clean before unscrewing and using a good tight-fitting socket.

Attachments crankcases-top-1946-left-1937-right-3-jpg

Submitted by roger_deadman on Mon, 20/08/2018

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Previously David Cooper wrote:

I find to my dismay that my (super-reliable until now) 16H inlet tappet can be rocked sideways a lot more than I expected. Looks like tappet guide?

The WD manual just says they are phosphor bronze and screwed into the crank case. But it doesn't say how. Am I right in supposing that they screw in from below, so it's a full engine strip? And I'll need a 1/4" reamer.

I don't yet know if they are available. Previous conversation here says they weren't easy to find a few years ago. I have a spare (rather rough) engine which might have an OK guide...maybe.

Any advice would be welcome. I could carry on using it I suppose, but I imagine it will get noisier and leakier quite quickly?

Thanks

David

Submitted by david_cooper on Tue, 21/08/2018

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Thanks Roger - I've mailed you direct.

For info to any others - I just spoke to Russell Motors and they don't have them.

Submitted by david_cooper on Mon, 27/08/2018

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Update...

Just removed guides from an old engine. No wear at all...so back to inspect mine and have another look. My engine is less worn, so why should one guide be worn?

Turns out the rear guide was not worn - it was loose - having come partly unthreaded. Of course it's near impossible to get a spanner in there, but cleaned it up and sacrificed a 3/16W spanner by grinding the edges back to make it narrower and also deepened the slot. Put that valve on maximum lift, and wound the guide out as far as possible. Ran some Loctite down around its edges, wound it back down, and tightened as much as possible with tips of spanner.

Fingers crossed!

I'm cautiously optimistic.

It's a bit odd, because both the guides in the other engine had clean but snug (stiff) threads. They were very tight but maybe bronze in alloy is looser when hot.

 


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