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04-11-2020, 04:06 PM | #1 |
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Join Date: Apr 2015
Location: Tamborine Mountain,Queensland, Australia
Posts: 85
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Adjustable tappets.
As my Covit-19 stay at home project, I have bulk stripped an old engine from a Phaeton that I have. It was completely seized and the oil in the sump was 100% sludge.
I want to re-assemble it at minimal cost but will be replacing the rings and grinding /lapping the valves and seats. My question is, can adjustable tappets be used with original mushroom stem valves. Not sure about grinding the valve stems to obtain the correct valve clearance. I know the purists in the group will advise me to do a complete valve job and discard the old valves and split guides but that would be defeating the object of my project (keeping the cost down) |
04-11-2020, 04:32 PM | #2 |
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Location: Lynden, Wa
Posts: 3,548
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Re: Adjustable tappets.
That is how my engine is put together. Just make sure all of the valves are the same length as that is how you adjusted the lash with non adjustable tappets.
Mike
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04-11-2020, 04:40 PM | #3 |
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Join Date: Dec 2014
Location: Shawnee, Ok
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Re: Adjustable tappets.
I hope you can use the mushroom stems...because I am.
I would get new guides, and be sure to check your cam before you make your parts order, to save you time, you'll most likely find that it is pitted beyond belief. I lapped my valves, easy job, new guides, new cam and the dowels, and don't forget a new plunger and spring. (cheap) Disassemble and clean your oil pump, easy job. Note on the cam, MAC's has a set criteria for the cam core, (has to be within specs) or they won't take it, Synder's on the other hand just needs a core, both are priced the same...so guess who I went with. No need to grind the valve stems, that's what the adjustable s are for You are going to need the valve spring compressor, valve guide removal tool and and the nut tool for the cam. Lapping your valves is cheap, just the hand tool and some lapping compound. And make sure you have plenty of clean rags when you do that, leave no compound, none, zero, zilch, nada behind, it will eat you motor.
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Keith Shawnee OK '31 SW 160-B |
04-11-2020, 08:03 PM | #4 |
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Join Date: Apr 2015
Location: Tamborine Mountain,Queensland, Australia
Posts: 85
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Re: Adjustable tappets.
From the two above replies, I assume it is OK to install adjustable tappets? Thanks for your list of suggestions burner31.Yes, using mushroom stem valves with split guides. Re. the cam. I have a couple of spares which are in good nick, so will choose the best of them and use that. If necessary, I can get one reprofiled here in Oz, too expensive sending one to the USA.
I'VE been unable to find an oversize stamp on any of the pistons so will have to mike them up and get a size that I can match up for the rings. All the bearings are white metal so will be able to set the clearances with new shims. The c/shaft journals are fine so no work required there! Any additional hints/tips would be appreciated. |
04-11-2020, 08:27 PM | #5 |
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Join Date: May 2010
Location: now Kuna, Idaho
Posts: 3,774
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Re: Adjustable tappets.
If you keep all the valves in their original positions and just hand lap them, most likely the clearance will still be OK. You won't remove enough metal to make a difference.
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04-11-2020, 08:27 PM | #6 |
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Re: Adjustable tappets.
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04-12-2020, 10:45 AM | #7 |
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Join Date: May 2010
Location: Alabama
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Re: Adjustable tappets.
I have used the original mushroom stem valves with adjustable tappets both single and double lock style without modification to the original mushroom stem . If I used modern valves, I needed to shorten the valve stem .
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04-12-2020, 10:49 AM | #8 |
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Join Date: Dec 2014
Location: Shawnee, Ok
Posts: 3,471
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Re: Adjustable tappets.
My valve lash was off anywhere from .01 to .07, among the eight valves, I can't grind the valve stems longer but I can use the adjustable s to bring them into tolerance.
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Keith Shawnee OK '31 SW 160-B |
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