Author Topic: Even more CS Questions  (Read 3017 times)

dieselspanner

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Even more CS Questions
« on: April 27, 2015, 08:54:19 PM »
Hi All

Well I've done most of the grubby bits on the collection of disparate parts that I hope will turn into a a 6/1 and I've 'dry fitted' them back together, as a practice run (and to stop me loosing them)!

I'm now waiting for a mate to bring the bits down to try and sort out the crank and the head.

A couple of questions,

What is the thread for the grease nipple in the rocker shaft? I've tried with the bits and pieces I have up here but can't match it.

The dipper it came with is home made,but longer than than the 'Indian dipper' I've acquired - (the Indian has a different thread from the 3/8" Whitworth in the con rod) so today I made a 'hollow dipper' - mostly 'cos it was raining and I was bored! - I have what appears to be a 1933 bottom end, with a 2 1/2" big end, plain main bearings and a splash plate. Do I use the hollow dipper or knock up a solid one? There seems to be a lot of conflicting advice on the site and I'd welcome everyone's opinion

Finally, the piston is an iron 4 1/2", with provision for four plain rings and  no oil control ring. The bottom housing is machined in a similar fashion to an oil control ring, with ports bored through to return the oil through the body of the piston. It has a little corrosion damage but looks like it has never worked hard and as the rings gap at 15 thou top and bottom it'll be going back in regardless of it's heritage!!

Thanks in advance

Stef

Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

Hugh Conway

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Re: Even more CS Questions
« Reply #1 on: April 27, 2015, 09:28:55 PM »
Hello Stef;

Replacing the grease cup with a grease nipple: 1/8 NPT is a match. Probably there is a similar Brit pipe size, but with a slightly different thread angle as with Whitworth and SAE. 1/8 NPT threads right in though.

Hollow dipper requires a different bearing shell, I think. seems like the old solid dipper works fine as is. I had a home made dipper in my Dursley, pretty crude and a bit short. the Indian replacement was so long that it hit the bottom of the sump. Easy to adjust however!

Cheers,
Hugh

JKson 6/1  (Utterpower PMG ) Off-grid
Lister 6/1 Start-O-Matic engine......running with PMG
1978 Royal Enfield (glutton for punishment by Indian iron)
1963 BMW R-27 project

38ac

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Re: Even more CS Questions
« Reply #2 on: April 27, 2015, 09:51:15 PM »
Actually the shaft is tapped for 1/8 BSP which is one thread per inch different than our NPT but in that application it makes little difference which you use.

You are indeed correct about the hollow dippers. what a person has to realize is very little is asked of the rod bearings in these engines. That meaning the area is very generous for the loading. That does NOT mean that rod bearings cannot be screwed up by sand, bad machining and assembly practice as has been experienced and noted by many users. As for special H=D shells needed, hogwash. What  is needed is cleanliness, proper assembly, proper pump timing and proper squish.  My opinion of hollow dippers is they are a routing around fixing the real problems stated above and backed by 50 years of Lister building the CS engine the same ole way. 
 
That being said if hollow dippers trip your trigger by all means use them, you end up with a system that Bamfords used successfully in the same time period and Lister also used on some of the twins.  If I wanted hollow dippers and couldn't find the special shells I wouldn't sweat it for a second and install the OEM replacements. You do of course need a hole in the bottom shell that is at least as large as the dipper hole.
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dieselspanner

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Re: Even more CS Questions
« Reply #3 on: April 28, 2015, 08:34:17 PM »
Thanks both,

Looks like the one fitting I had at 1/8" BSP was a bit more mangled than I thought, still at least I resisted the temptation to drive it home regardless.  I'll be Ebaying for a new 1/8" tap directly!!

38ac

To be honest things that trip my trigger are getting fewer and farther between as time goes on, 2 1/2" of remodeled secondhand Whitworth bolt ain't even close!

The crank has been run in sand and is well shot, I've cleaned it up and it'll need a -60 thou bearing. I've got some 2mm ally plate on the way over and I'll have a go at Starfire's diy method.
As the end is going to need all the help it can get, - I've not had a hand in scraped bearings in 45 years! - I'll take heed of your comments and add the hollow dipper as a belt and braces move.

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.