Jump to content

J2 how much crankshaft float?


Mike Adams

Featured Posts

Was trying to set up my starter for the correct clearance from the flywheel. Noticed that if you push the flywheel back and forth(fore and aft) there is a clunck and about 1mm movement. Makes it tricky setting the clearance. Is this normal for this type of engine or might it be Knackered?

Link to comment
Share on other sites

11 hours ago, Mike Adams said:

I am not sure what sort of thrust bearing arrangement there is if any.

 

There must be something, somewhere. The cone clutches rely on prop thrust to stay engaged. 

 

The end thrust could, I suppose, be in the Kelvin gearbox but that seems unlikely. 

Link to comment
Share on other sites

From memory, there's a ball bearing thrust "washer" between the ahead clutch and the rear crankshaft cover plate,in the gearbox. If the ahead clutch hasn't been fitted up properly on the end of the crank, there could  be end float. Other than that there are bearing faces on the mains, if worn they will cause it as well. NB  memory, not as good as it was.?

Link to comment
Share on other sites

The petrol paraffin engines use a ball  thrust bearing, the diesels use a large deep groove ball bearing in a housing behind the ahead clutch, this is quite an expensive bearing compared to the rest of the gearbox bearings.

 

IMG_1611.JPG.6b1d6180c9eafe5412eaafdb86ed0454.JPGIMG_1612.JPG.ac274811cc4c30936329799c70186617.JPG

 

the first photo shows the thrust bearing, the second shows the ahead clutch fitted.

the diesels use a different bearing.

hope this helps

Tom 

Edited by tom_c
Link to comment
Share on other sites

May I hijack this thread briefly?

 

I have a K2 with a Velvet Drive grafted onto the back in place of the K transmission. Does this mean my engine is possibly running with no end float control? 

 

Or is there another (less robust) end thrust bearing on the crankshaft? 

Link to comment
Share on other sites

Hi Mike, the bearing arrangement on the diesels is different, they have a bearing housing bolted to the crankcase containing the bearing, it just depends what is fitted to the end of the crank, is it a marine engine or a lighthouse engine? 

I have a pair of 13/15HP poppet valve cranks, one marine and one land engine the two cranks are significantly different but I'm not sure the K's followed suit 

Tom

Link to comment
Share on other sites

3 minutes ago, tom_c said:

Hi Mike, the bearing arrangement on the diesels is different, they have a bearing housing bolted to the crankcase containing the bearing, it just depends what is fitted to the end of the crank, is it a marine engine or a lighthouse engine? 

 

Hi Tom, thanks for your reply.

 

I don't actually know. All I can say is it came with several boxes of bits which look as though they could be assembled up into a K reversing gear. I doubt lighthouse engines came with a reversing gear so my guess is it is the marine version.  

Link to comment
Share on other sites

1 hour ago, Mike the Boilerman said:

May I hijack this thread briefly?

 

I have a K2 with a Velvet Drive grafted onto the back in place of the K transmission. Does this mean my engine is possibly running with no end float control? 

 

Or is there another (less robust) end thrust bearing on the crankshaft? 

Hijacking again - How do you get on with the Velvet drive Mike? I have a K2 with UJ's at each end of the pro shaft and no support bearing at the drive end which I know puts a stress on the Kelvin gearbox bearing (white metal bearing) although running fine at present. Its a lot of work to retrofit a support bearing so one of the solutions is to replace the Kelvin gearbox with a 1:1 Velvet drive so would be interested in your experience.  

Link to comment
Share on other sites

 

4 minutes ago, BrandyMark said:

Hijacking again - How do you get on with the Velvet drive Mike? I have a K2 with UJ's at each end of the pro shaft and no support bearing at the drive end which I know puts a stress on the Kelvin gearbox bearing (white metal bearing) although running fine at present. Its a lot of work to retrofit a support bearing so one of the solutions is to replace the Kelvin gearbox with a 1:1 Velvet drive so would be interested in your experience.  

 

The Velvet Drive works really well except for one problem. I didn't install it, came with the boat so I dunno how it is coupled up. I suspect there is a modern drive plate in there somewhere and it isn't man enough for the job. I get that unpleasant 'clanking' noise a failing driveplate makes when in gear at tickover.

 

I feel inclined to take it to bits, find the drive plate and weld it up solid. 

Link to comment
Share on other sites

Stick with the Kelvin box, it just works and will keep on working . It was designed for that engine, I doubt the Velvet thing was, more like one size fits all ,or not......

6 minutes ago, Mike the Boilerman said:

 

 

The Velvet Drive works really well except for one problem. I didn't install it, came with the boat so I dunno how it is coupled up. I suspect there is a modern drive plate in there somewhere and it isn't man enough for the job. I get that unpleasant 'clanking' noise a failing driveplate makes when in gear at tickover.

 

I feel inclined to take it to bits, find the drive plate and weld it up solid. 

 

Link to comment
Share on other sites

2 minutes ago, billh said:

Stick with the Kelvin box, it just works and will keep on working .

 

Yeah right! The Kelvin box on my other Kelvin is a PITA and I'm thinking of replacing it with a velvet drive too. 

Link to comment
Share on other sites

8 minutes ago, Mike the Boilerman said:

 

 

The Velvet Drive works really well except for one problem. I didn't install it, came with the boat so I dunno how it is coupled up. I suspect there is a modern drive plate in there somewhere and it isn't man enough for the job. I get that unpleasant 'clanking' noise a failing driveplate makes when in gear at tickover.

 

I feel inclined to take it to bits, find the drive plate and weld it up solid. 

Thanks for info, would be very interested when/if you take it apart what you find - would give you a hand if you wanted. I was wondering about the drive working with low rpm i.e. sufficient hydraulic pressure but it sounds like this is not a problem.

 

Link to comment
Share on other sites

2 minutes ago, Mike the Boilerman said:

 

Yeah right! The Kelvin box on my other Kelvin is a PITA and I'm thinking of replacing it with a velvet drive too. 

Why is it a PITA? Are you trotting out the old "it keeps dropping out of gear " thing?

Link to comment
Share on other sites

9 minutes ago, billh said:

Stick with the Kelvin box, it just works and will keep on working . It was designed for that engine, I doubt the Velvet thing was, more like one size fits all ,or not...…

 

Kelvin engine and gearbox in a sea going boat is doing what it was designed to do, we are using them in a narrowboat which requires far more frequent use of the forward/astern movement and I think this is the cause of concern on reliability (suitability) of the Kelvin gearbox. In my case, I think it as been made even more of a concern because of the installation which again is not as sea going Kelvin with solid prop shaft but using two UJ's. To support the prop shaft correctly for the Kelvin gearbox i.e. with a bearing at each end, then you need to engineer a bearing arrangement which can provide both linear and rotating loads which is not easy to do hence, the option of using a Velvet drive is worth investigating.

Link to comment
Share on other sites

13 minutes ago, BrandyMark said:

Kelvin engine and gearbox in a sea going boat is doing what it was designed to do, we are using them in a narrowboat which requires far more frequent use of the forward/astern movement and I think this is the cause of concern on reliability (suitability) of the Kelvin gearbox. In my case, I think it as been made even more of a concern because of the installation which again is not as sea going Kelvin with solid prop shaft but using two UJ's. To support the prop shaft correctly for the Kelvin gearbox i.e. with a bearing at each end, then you need to engineer a bearing arrangement which can provide both linear and rotating loads which is not easy to do hence, the option of using a Velvet drive is worth investigating.

Yes I know all that. Experience tells me different.....

Our  wooden narrow boat was built in 1948 and fitted with a Kelvin, solid prop shaft with Kelvin taper couplings at engine end and tailshaft  end, total about 12ft. Two intermediate plain bearings with greasers to allow the shaft to slide axially. In daily use until 1962 then leisure use from 74 to 82. Rebuilt with a bigger Kelvin , in use from 1989, now with a short LandRover  shaft,2 U/Js between gearbox and mainshaft. Plenty of F-N-Rs on lock flights and prop clearing. Only now after nearly 30 years are the clutches showing signs of wear, it needs more turns of the control wheel and the thrust box leaks a bit of oil.No gearbox internals have been needed and  it doesn't drop out of gear unless you want it to. I reckon that's pretty reliable. 

Link to comment
Share on other sites

29 minutes ago, billh said:

Yes I know all that. Experience tells me different.....

Our  wooden narrow boat was built in 1948 and fitted with a Kelvin, solid prop shaft with Kelvin taper couplings at engine end and tailshaft  end, total about 12ft. Two intermediate plain bearings with greasers to allow the shaft to slide axially. In daily use until 1962 then leisure use from 74 to 82. Rebuilt with a bigger Kelvin , in use from 1989, now with a short LandRover  shaft,2 U/Js between gearbox and mainshaft. Plenty of F-N-Rs on lock flights and prop clearing. Only now after nearly 30 years are the clutches showing signs of wear, it needs more turns of the control wheel and the thrust box leaks a bit of oil.No gearbox internals have been needed and  it doesn't drop out of gear unless you want it to. I reckon that's pretty reliable. 

A narrowboat with a Kelvin in 1948, that's is interesting, thanks for letting me know, its gives me more confidence in the Kelvin gearbox. I was under the impression that R W Davis was the first to fit Kelvin's in narrowboat's in his "Northwich Traders" - I wonder if he copied you! My gearbox/prop shaft setup works fine so far, I'm just thinking of long term reliability after reading about the failure of a similar installation on another narrowboat. Thanks for sharing. 

Link to comment
Share on other sites

6 hours ago, BrandyMark said:

A narrowboat with a Kelvin in 1948, that's is interesting, thanks for letting me know, its gives me more confidence in the Kelvin gearbox. 

It's better than that, our boat's predecessor, of the same name, was motorised  from a horseboat in 1927 , fitted with a Kelvin E2 petrol/ paraffin engine, rated at 9HP. The work was done under the auspices of the canal's owners, the London & North Eastern Railway  at Gorton Canal Depot in Manchester.

OK , the gearbox was smaller than the slightly more modern J s and Ks, but the working principle is exactly the same. That boat worked day in day out on  canal maintenance until 1948 when it was replaced as being "worn out" ( the boat not the engine). I am a Kelvin enthusiast, does it show??

Link to comment
Share on other sites

I suspect the  gearbox unreliability story was developed to aid the sale of a job lot of  ex lighthouse compressor Ks , which wouldn't have any gearbox , so a cheaper (more profitable?) alternative could be fitted. Unlike our canal boating , many Kelvins were installed in small fishing boats where lives depended on a reliable engine ( and gearbox), they had to get you safely  home  every day . Also, as I understand it , in some types of fishing there is a lot of slow running engine with many reverse or idling periods- not so different from the performance required in canal locks.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.