Author Topic: Sludge trap plugs  (Read 3574 times)

Offline mark

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Sludge trap plugs
« on: 17.08. 2009 00:38 »
I have just removed the two plugs and cleaned the sludge trap. The plugs were both flush with the surface of the web when I removed them. I have noticed that the plugs will screw in further until they hit the end of the thread so they are recessed by a few mm. This is the early big journal crank without a tube. My question is, should I replace them flush like they were or tighten them fully. I guess my concerns are 1- If I don't tighten them fully is there a chance that they will loosen even with loctite and 2- If I do tighten fully will the timing side plug restrict the oil flow. All comments gratefully received.
Mark
55 road rocket




71 Norton Commando Roadster 750


Australia

Offline Josh Cox

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Re: Sludge trap plugs
« Reply #1 on: 17.08. 2009 03:55 »
Hi Mark,

Be very careful how far you screw in the timing side plug, as the plug could cover the oil hole, I have just put new plugs in my small journal crank ( which is what yours would probably be, not having a sludge tube ).

The plug is supposed to be really tight in the hole and flush, are you certain you have the correct plugs ?.

Good luck,

Josh
Black 1953 Golden Flash Plunger

Online RichardL

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Re: Sludge trap plugs
« Reply #2 on: 17.08. 2009 04:27 »
Gents,

Correct me if I'm wrong, early cranks without sludge-trap tubes were not large diameter big ends (large being 1.687" STD), correct? Mark, are you sure this is not a case of a previous mechanic leaving out the slude-trap in error or because he thought the bike would be better off without it?

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline mark

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Re: Sludge trap plugs
« Reply #3 on: 17.08. 2009 05:46 »
This crank is out of a 1956 road rocket, it is definitely large journal and couldn't have a tube as the hole narrows down inside. The hole is 5/8'' for 2'' deep on the drive side and 1/2'' deep on the timing side, in between it narrows to 3/8".  The plugs that came out were very tight and seemed correct. The parts catalogue gives the same part number 65-0615 for the 56 road rocket as the 54 A10 even though the cranks have different numbers. I'm guessing that this is the first of the big journal cranks and they changed later to have the tube. Looking at the timing side it appears that the oil hole will not be fully covered by the plug if it is screwed home fully but to be safe I think that I'll put it back the way I found it as it was full of sludge so it had done its job and loctite and a centre punch should ensure that they won't move.
55 road rocket




71 Norton Commando Roadster 750


Australia

Offline trevinoz

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Re: Sludge trap plugs
« Reply #4 on: 17.08. 2009 22:16 »
Mark,
           I guess you have the one piece billet crank which weighs a ton!
Loctite the plugs and stake them if you feel it necessary. I would replace them with Allen head plugs.
Trev.

Offline mark

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Re: Sludge trap plugs
« Reply #5 on: 18.08. 2009 00:05 »
Trev
It certainly weighs more than the later one with the 3 bolts that I started out with but the chap doing the bottom end was unhappy with that one as he feels that it may have a fault because when the webs are hit with a hammer one side "rings" well and the other is dull. He says that in his experience this usually means a crack. So I took this one out of my "parts" engine and I feel that it is probably the correct type for the 55 rocket that I'm restoring. Do these heavier ones have any known issues and are they suitable for a tuned engine as I intend to use the spitfire cam and big valve head that came with it
Regards
Mark.
55 road rocket




71 Norton Commando Roadster 750


Australia

Offline trevinoz

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Re: Sludge trap plugs
« Reply #6 on: 18.08. 2009 22:48 »
Mark,
            I have not heard of any problems with these cranks. A mate has had them in Rockets in the 50s and 60s and reckons they are great once you get the engine wound up. He intends using them in his early Rockets when he gets around to them.
He offered me one for my '54 RR project but lack of rods to suit will probably put paid to that idea.
Trev.

Online RichardL

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Re: Sludge trap plugs
« Reply #7 on: 19.08. 2009 00:07 »
Question: is the one-piece crankshaft truly an intentional "sludge trap", considering it has no tube?

This whole topic has revealed to me something I am a bit embarrased to admit. I didn't realize that I had a '58 or later crank in my '55 until I reviewed the whole thread, last night. I went to my parts book to see the differences between my crank and Mark's, only to discover that my parts book basically shows Mark's no-tube type and not my own tubed, large-diameter type. Oh well, I guess that's one less link to the hallowed date of birth (the bike's, not mine).

 I now think that this glitch in my knowledge at the time of my first rebuild contributed to the big-end failure. I spent endless time studying the exploded views in my parts book, so, never having seen a sludge-trap tube I did not give it due attention and, voila! 3O years (at least) since the last cleaning jumped out to bite me. I learned better for the next rebuild, which, knock wood, has been running great for 900 miles. I also give some blame to the Haynes manual that puts so little emphasis on the sludge trap instead of something like, "HEY YOU, NEWBIE, DON'T FORGET TO CLEAN OUT THE FREAKIN' SLUDGE TRAP!!!!!!!!!"  

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Offline Josh Cox

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Re: Sludge trap plugs
« Reply #8 on: 19.08. 2009 08:23 »
Quote
HEY YOU, NEWBIE, DON'T FORGET TO CLEAN OUT THE FREAKIN' SLUDGE TRAP!!!!!!!!!

I've got better than any crappy Haynes Manual, I've got an "Orabanda" busting my balls to do it right, for which I am very very grateful.
Black 1953 Golden Flash Plunger

Offline WozzA

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Re: Sludge trap plugs
« Reply #9 on: 16.02. 2012 05:32 »
I did mine yesterday   *smile*   & it's the same as Mark discribed..  NO TUBE in there..  ????
57 Swingarm


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Offline trevinoz

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Re: Sludge trap plugs
« Reply #10 on: 16.02. 2012 21:11 »
That's right, Wozza, no tube in the small journal crank or the one piece large journal billett crank.

Trev.

Offline WozzA

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Re: Sludge trap plugs
« Reply #11 on: 16.02. 2012 23:07 »
 ????  so is mine is the small journal crank then Trev ??
'51 Golden Flash Plunger
'57 Golden Flash Swingarm

Melbourne
The biggest lie I tell myself is
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Offline muskrat

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Re: Sludge trap plugs
« Reply #12 on: 17.02. 2012 20:43 »
Sure is WozzA. Yours has the six bolts holding the flywheel and 1.461" big ends. The LJ has 3 bolts radially and 1.688" big ends.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline WozzA

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Re: Sludge trap plugs
« Reply #13 on: 17.02. 2012 20:55 »
Thanks Musky...  It wont be getting thrashed around  *roll*
so it can go back in after a clean up & new big end bearings..
'51 Golden Flash Plunger
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Melbourne
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Offline muskrat

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Re: Sludge trap plugs
« Reply #14 on: 17.02. 2012 21:45 »
Just had another look at the pic. It might be the heavy one piece jobbie. Does it have the six bolts?
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7