B25 Inlet pushrods (unobtanium)

Started by AltcarBob, 01 Sep, 2023, 12:44

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AltcarBob

I have pulled the top end off my b25 to try and locate a rattle and I have discovered I have a pair of exhaust pushrods. No worries thinks I then I try to order an inlet pushrod and discover that no one seems to have them and no one seems to know when they will be back in stock.

Do I need to worry or just do what the previous owner did and just adjust the tappet and ignore the extra rattling. After all it's a BSA unit single and it's a symphony of rattling.
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Stubaker58

I was intrigued by the inlet and exhaust being different lengths, but it is so. RR has an instructive paragraph (p139). The exhaust should be 1/16" shorter, apparently they can be lengthened by taking off the metal cap and inserting a small disc of the correct thickness and replacing the cap. (Or take a C15 rod and shorten it).
Hope you get it sorted.

AltcarBob

RRatio doesn't say how to get the steel end off and I tried tapping it but its not shifting. The rod is only ally or I would give it a good smack but don't fancy it. I suppose it's going to need heat but again I don't fancy getting the blow torch on it.
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Stubaker58

I've got a spare C15 rod (somewhere!) which I don't mind experimenting on, I think the aluminium will be fine heated up. I'll let you know.

AltcarBob

Quote from: Stubaker58 on 01 Sep, 2023, 16:47
I've got a spare C15 rod (somewhere!) which I don't mind experimenting on, I think the aluminium will be fine heated up. I'll let you know.

Thanks your braver than me
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Stubaker58

Ok, so the bad news is that it took a lot of heat and then the application of force via a small set of vice grips to get the end cap off. The end of the aluminium rod was pretty chewed up as was the outside of the cap. I'm sure that it could be re-united but it's not easy. (No useable parts were harmed in this experiment as the other end of this particular rod is pretty rough).

The good news is that of the spare rods that I've got one is 7 5/16", which I think is what you're after?

PM me if you're interested.

AltcarBob

I have sent you a pm, I think, I am using a replacement phone and it's not one I am used to.
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KCF21

You need to make a little pusher - please see photo,
Kevin

Stubaker58


AltcarBob

Quote from: KCF21 on 03 Sep, 2023, 14:59
You need to make a little pusher - please see photo,
Kevin

Good bodge 👍 did you need any heat as well and what did you use to extend the rod I was thinking a small washer.
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AltcarBob

Thanks to Studebaker 58 I have a slightly over length C15 pushrod which I am going to cut down on a lathe. With the supervision of someone who actually knows how to use a lathe of course I would probably end up losing a few fingers if I wasn't supervised  :o
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Dean Southall

I wouldn't apply heat. The alloy rods will expand more than the steel caps making them grip all the more securely!

If the rods are past it then dural rod is available, just cut to length and cold press the caps on.
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