Pushrod tube replacement (type 4)

Discussion in 'Mech Tech' started by 62 deluxe, Jan 1, 2022.

  1. Zed

    Zed Gradually getting grumpier

    IIRC older engines, (maybe it was 1700's but don't quote me) had slightly longer tubes. Another case of one size after market part fits all... but not quite. Many years ago when nobody in the uk wanted type-4 engines (e.g. I couldn't sell a running, no float 1700 for £50) I had a collection of push rod tubes to pick the long ones out of. Or maybe they had shorter tubes - it was one or the other, but the length did change at some point.
     
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  2. 77 Westy

    77 Westy Supporter

    Apparently early 1700 tubes are slightly different and according to samba Ray only on 411 engines up to 1970. I don’t know if the difference is the length or if the tube is shaped (to clear the exhaust or an installation tool), the head end O-ring is smaller too.
     
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  3. Zed

    Zed Gradually getting grumpier

    Length, I've possessed some and it's 2-3mm. :thumbsup:
     
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  4. 77 Westy

    77 Westy Supporter

    I’ve just ordered a set of SS tubes from JK, £9.02 each with the TLB discount and UK delivery is included.
     
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  5. mcswiggs

    mcswiggs Supporter

    Very nice, I’ll grab a few too. I can never get the discount code to work - are you using THELATEBAY?
     
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  6. 77 Westy

    77 Westy Supporter

    I couldn’t find a code so I sent a message on the JK website asking if there was TLB discount and received an email saying my account had been updated to include the discount. Logging on now I see the reduced price, it’s not a lot but better than nothing.
     
    Last edited: Jan 10, 2022
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  7. Norris

    Norris Supporter

    I just bought "normal" steel replacements for mine. If they last another 40 years, that'll do for me
     
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  8. Well fitted the new SS tubes with Viton seals using the oil dunk method having thoroughly cleaned the housings and I have a tube on no.1 and on no.4 leaking oil at the head end:mad:
     
  9. 77 Westy

    77 Westy Supporter

    Yes, but do they look nice? :)
     
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  10. They look sparkly (unlike the rest of my westy)
     
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  11. Had chance to look at it yet.I’m intrigued! We’re the head ends the wider than standard groove for the seal?
     
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  12. davidoft

    davidoft Sponsor

    you have to feed the seals in with a small flat screwdriver or they will get cut as they go in
     
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  13. Which… the head one or the bottom end one? Never done that. Just relied on the lube to get them in. What cuts them? The edges of the ribs on the tubes?
     
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  14. davidoft

    davidoft Sponsor

    the head end, when you do lots it’s a time gamble not worth the time saved by taking a few seconds, it’s not always but some heads are cut your fingers sharp on the edges
     
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  15. I took them out, the seals looked ok, but I cleaned and sanded any sharp edges, then used a polishing mop on my dremel and went over the edges and bores and cleaned again. Lubed new seals with oil and fitted but still leaking!
     
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  16. Here’s some pics
     

    Attached Files:

  17. Yes the head end has the slightly wider grove.
     
  18. Zed

    Zed Gradually getting grumpier

    That first photo - the seal is almost pushed right through the head. Methinks your tubes are a bit short for your engine and you could do with spacers at the case end as @77 Westy has.
     
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  19. 77 Westy

    77 Westy Supporter

    This^. The tube is too short consequently the head end O-ring is too far through the head.

    I made a spacer from a ring of wire to fit in the crankcase, a machined spacer would be neater but at the time I didn’t have access to a lathe. Be very careful not to scratch the sealing face in the case, the spacer does not need to be a tight fit.

    What’s the spec of your engine, do you have cylinder spacers?
     

    Attached Files:

    Last edited: Jan 17, 2022
    62 deluxe likes this.
  20. The others are ok but do you think when the engine heats up completely they could also leak due to expansion?
     

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