Dorman 4DSM problems

[Ads]

Ive recently had a Dorman 4DSM installed in my 60ft narrowboat but im having problems.

 

The engine goes in and out of gear fine the engine revs up and the prop turns but it doesnt seem to have enough kick if you know what i mean?

Its as if its under proped but i dont think that is the case as alot of calculations went into it.

The first thing that comes to mind is that something is slipping from within the engine any idea what this could be? or does anybody no anyone else that might?

any pointers would be a great help!

 

Cheers

 

Adam

[Keeping Up]

Just to give us the complete picture:

 

What dimensions of prop have you got?

What type of gearbox is it, and what ratio?

Do you know how many engine rpm you were trying it at?

 

Are you sure you didn't pick up something on the prop?

Elementary questions I know, but you hadn't given us much info to base all our stupid guesses on.

 

Allan

[Ads]

Thanks for pointing that out your right i should have really put that down.

 

The prop is a 22 with a pitch of 20 i brought this prop from Crowthers they said really i should have a 27 but as this would not fit the swim we went with the 22/20 with a bigger blade area.

 

The gear box is a 2:1 and is the standard box for this engine built by Dorman (i think) as all the dormans i have seen have all had the same looking box.

 

I was trying it through the whole rev range 200-1300rpm it moves but at about 2mph

 

There is def nothing round the prop as it has done this since we put the boat in the water four weeks ago

 

Thanks

 

Adam

[dcruk]

if the gearbox is mechanical ie not hydraulicly engaged , prevent the engine from being started , put it in gear and try to turn the prop through the weed hatch , may be something as simple as the prop key is missing . If it turns , Just work along the line of the propeller shaft until something isn't moving with the rest of the bits. worth a try , Dave

[David]

Hi

Just a thought, on our 62' footer we swing a 22" prop (Crowther) on the Kelvin, our rev range is 220 to 1000, pretty near to yours, but the ratio is 1:1 direct of the crankshaft, so maybe your reduction is the problem.

david

Edited March 7, 2006 by David

[Keeping Up]

As your shaft rotates relatively slowly I reckon you could eliminate (or confirm) any suspicion of slippage in the gearbox or couplings by counting the revs of the shaft itself; quite difficult to do by eye but not so hard by feel/sound by, for example, putting a jubilee clip around the shaft and letting it tap against a screwdriver. You should be able to count at perhaps 250 rpm that way (that's just over 4 per second; you count the 'ticks' while someone else times maybe 10 seconds for you) which would be 500 engine rpm. If the shaft revs are what you expect, look beyond the shaft (prop, keyway, etc).

 

On our boat with a modern engine and a 3:1 reduction, 650 propshaft rpm (which should be what you're getting up to) would be 1950 engine rpm, at which we would be doing over 4mph with a smaller (18x14) prop. Ours is a 67 foot boat, probably not as deep-draughted as yours but I'm sure you should be moving better than you are. Have you checked that there isn't a jetty covered in bollards following about 10 feet behind you?

 

Allan

[Ads]

I was having a quick mess around with it last night and checking the shaft wasnt slipping i put the engine in gear at about 200rpm i then pushed my foot down on one of the shaft couplings and was able to slow the shaft down but the engine was still reving the same. surely on an engine of that size even a 200rpm i shouldnt be able to slow the shaft down with only the pressure of my foot?

 

Does anybody know any companys that specialise in Dormans?

 

Thanks

 

Adam

[alan_fincher]

I was having a quick mess around with it last night and checking the shaft wasnt slipping i put the engine in gear at about 200rpm i then pushed my foot down on one of the shaft couplings and was able to slow the shaft down but the engine was still reving the same. surely on an engine of that size even a 200rpm i shouldnt be able to slow the shaft down with only the pressure of my foot?

 

Does anybody know any companys that specialise in Dormans?

 

Thanks

 

Adam

Adam,

 

Unless I'm being dense, if you are able to slow the shaft WITHOUT slowing the engine, then the problem must be either the gearbox, or the shaft rotating in the coupling where it joins the gearbox, surely ?

 

I don't know this engine, and how the gears are engaged, but are you sure whatever mechanism is doing it, (rodding, cable, etc), is fully engaing the gears ?

Edited March 8, 2006 by alan_fincher

[John Orentas]

You have obviously found the problem Ads. You must have a clutch in there that is slipping for some reason, if it is hydraulically actuated simply topping up the gearbox oil might do the trick. Also double check that the external linkages are getting full movement, push them a little further when it is 'slipping' does that improve things.

 

As presumably the problem only began when you changed the prop, what have you disturbed or altered, or it could just be the extra load of the bigger prop has made the difference.

 

I think intimately you will have to find someone with knowledge of that particular gearbox. One two gearbox specialist advertise in the mags.

 

Bob Knowles.........................0116 255386685

Carvers transmissions...........0161 320 3400

 

You may also find TW Marine helpfull...........01663 745757

Edited March 8, 2006 by John Orentas

[Ads]

Thanks for that irl give them a ring.

 

Ive adjusted the clutches on the box and from what i can see its going in an out of gear perfect. but as i first thought something some where is slipping?? someone has mentioned to me about clutch bands?? but to be honest i dont really know what these are?

 

Cheers

 

Adam

[John Orentas]

Thanks for that irl give them a ring.

 

Ive adjusted the clutches on the box and from what i can see its going in an out of gear perfect. but as i first thought something some where is slipping?? someone has mentioned to me about clutch bands?? but to be honest i dont really know what these are?

 

Cheers

 

Adam

 

The box is likely to be of there own manufacture so the clutch type could be almost anything, they are not that rare so you should find someone with some knowledge of them. If not you may have to open it up and take a look. Good luck.

[Ads]

Rang Bob Knowles interesting guy he said i rang him the other day and he didnt want to know and hung up! ive never spoken to the man before! Crazy....

 

Doesnt look good to potential customers hes obviously far to busy to help anybody else!

[Alec Gatherer]

I get the feeling that Bob Knowles is labouring under a deluge of people phoning him with a barrage of questions covering the entire spectrum of boat gearboxes.

I am one of them - I phoned him about a possible gearbox for a Lister HR3 industrial engine I have. To be honest, after a diatribe about how many people phone him with these spurious enquiries, he was really helpful and I was glad of his advice.

Being in a similar position with Riley cars, I am on Bob's side considering the number of calls us specialists get per day - it really is impossible to get any work done sometimes (though politeness never hurt anyone).

[John Orentas]

Well in view of the fact that the chap advertises in every boating mag there is I think it is a bit churlish to complain when people ring him up. Perhaps he should have a recorded message saying 'I won't talk to anyone who can't guarantee me a profit'.

Edited March 8, 2006 by John Orentas

[Ads]

I can understand he prob does get alot of phone calls but like you say POLITENESS never hurt anyone. If he had an idea of what i could be i would have gladly paid him to fix it im not looking for free b's.

 

Oh well his loss i guess.

 

Ive now spoken to TW Marine and the guy there seemed to be willing help find out what the problem could be and ive sent him some pictures of the box as to establish what box exactly it is.

 

Im a bit of a vintage engine virgin so this is a big learning curve for me. maybe i should have stuck with the standard Jap engine.

 

Adam

[David]

Hi again

If you have clutch bands, they can be worn which sounds like the problem if you can slow the shaft as you say with your foot.

They are in a way similar to old fashioned drum brakes, they have a lining material which conveys the engine power/rotation to the mechanical part of the gearbox, if they are worn or not adjusted correctly or contaminated just like drum brakes when worn etc will not stop you they will slip when any load is put on them, hence the shaft slowing when you put load on it.

Our Kelvins have a cone clutch which uses lining material which needs relining ever so often (though some have steel to steel cones).

If that is your problem there are lots of reliners lots of industrial ones for cone clutches and bands as they are common for hoists and lifting gear type stuff , plus some vintage car refurbers etc . Put cone clutch or brake bands into your search engine.

[Ads]

Right think i might have narrowed it down to a couple of things.

 

Either the clutch bands are worn out or the clutch plates im going to have one more play to see if i can adjust it to correct it if this doesnt cure it im going to hand it over to Paul Redshaw.

 

 

Adam

[denboy]

Well in view of the fact that the chap advertises in every boating mag there is I think it is a bit churlish to complain when people ring him up. Perhaps he should have a recorded message saying 'I won't talk to anyone who can't guarantee me a profit'.

he is very very arrogant i asked him what oil went in an enfield outdrive a few years back he repplied have you got a fiver yes i repplied good he said heres the manual only a fiver??and i know of some other horror stories nof people who have used him

[DHutch]

he is very very arrogant i asked him what oil went in an enfield outdrive a few years back he repplied have you got a fiver yes i repplied good he said heres the manual only a fiver??and i know of some other horror stories nof people who have used him

Although, tbh, im sure he has a point. For a fiver, its worth having for sure.

- Its often the case that these people to get fed up with "silly" questions from inexprenced people, and at times, i can understand why.

 

Just a little a-side, My cosin bought a RC helicoppter from a (very good) model shop, with promise of good support, however, after about 3/4 vists, the owner started geting very unhelpfull and short tempered towards them and there dad.

- But then when i took the heli and my cosin down to the shop, they where very helpfull, becuase although im into cars, rather than heli's, i could "talk the talk" and he no longer had to explan everythink to my cosin slowly enough for a total noob to understand, instead, he got on with it, while i relay the info to my cosin at a steped down leval.

- While im not saying he was right to get fed up with them, i can understand how it happens, they feel there doing all the work, and geting nothing (or very little) back in return

 

 

Daniel

Edited March 9, 2006 by dhutch

[John Orentas]

Although, tbh, im sure he has a point. For a fiver, its worth having for sure.

- Its often the case that these people to get fed up with "silly" questions from inexprenced people, and at time, i can understand why.

 

Daniel

 

 

I can't agree with any of that, when you are in business you will occasionally get casual telephone enquiries, that is a small price to pay for being in business, if you don't respond to them you risk alienating your own potential customers.

 

This particular case is a good example, Ads genuinely wanted his gearbox sorted out, if Knowles did not have such a boorish manner he may well have got the job, if he doesn't want the job he is wasting his money on advertising.

 

He probably hasn't won himself many friends on this forum either.

Edited March 9, 2006 by John Orentas

[Ads]

I think the Bob does have a bit of a reputation ive been having quite a few chats with Paul Redshaw and when i mentioned i had tried to contact Bob about my box he said "did he tell you to piss off" i said oh hes told you ive already spoken to him and paul replied with "thats just what hes like".

 

But like i said Bobs's loss in my eyes as i may just give paul the whole job and ask him to sort it..

 

I must say ive found Paul Redshaw very helpfull so far

 

Anybody else used him or Tony?

 

Adam

[Cafnod]

I can't agree with any of that, when you are in business you will occasionally get casual telephone enquiries, that is a small price to pay for being in business, if you don't respond to them you risk alienating your own potential customers.

 

This particular case is a good example, Ads genuinely wanted his gearbox sorted out, if Knowles did not have such a boorish manner he may well have got the job, if he doesn't want the job he is wasting his money on advertising.

 

He probably hasn't won himself many friends on this forum either.

 

 

Quite John

Dealing with people who were not certain of the nature of their problem, or those who needed advice was regarded as goodwill when I was in business. These people are not 'grey box shifters' but put themselves forward as specialists in their fields, offering services of a highly technical nature, therefore they should expect people to ask questions they find basic.

when you advertise that you can deal with vintage kit people who dont understand it will come knocking. If you dont want the punters then only deal through third parties in the trade.

[Alec Gatherer]

Fair point. I am delighted to help with queries from anyone in my particular field of expertise (Riley cars) but not so delighted to crawl out from under a car, turn the oxy torch off, extinguish a fire I started on the way out, grab the phone, only to find it's a query that could havce been answered by a quick look in the manual but they thought it would be easier to phone me and ask.

To combat that I had the phone taken out at work (the one everyone knows about, anyway) and bingo! no-one stops me from working any more.

[Cafnod]

Fair point. I am delighted to help with queries from anyone in my particular field of expertise (Riley cars) but not so delighted to crawl out from under a car, turn the oxy torch off, extinguish a fire I started on the way out, grab the phone, only to find it's a query that could havce been answered by a quick look in the manual but they thought it would be easier to phone me and ask.

To combat that I had the phone taken out at work (the one everyone knows about, anyway) and bingo! no-one stops me from working any more.

 

 

Hi Alec

Very good point too, I was not for one moment suggesting that one should be available for any amount of stupid questions 24/7 from timewasters. We always had an answer phone with a courteous message on it and a mobile for any personal emergencies.