BMC 1.5 Timing Chain & Tensioner Renewal.

[Southern Star]

I'm thinking it might be a good idea to start thinking about changing the above, my engine has about 2,500 hours on it and the boat is around 28 years old. I wonder if anybody has done this job, and whether there are any hints and tips etc they could pass on? Alternatively, anyone in the Rugby area who could be recommended to do the job in case I decide it's better left to an expert?

[RLWP]

I have a BMC 1500 in the workshop at the moment. I'll take some pictures of the timing chain work, you can then decide if you want to do the job or not

 

Richard

[Southern Star]

Thanks Richard, that would be hugely appreciated. Can the job normally done with the engine in situ? And if so, how long would it take a proper boat fitter to do it?

[pete.i]

Might be a good idea to have a look at the workshop manual for the BMC 1.5 in conjunction with Richard's pictures. It can be found here:-

 

http://the-norfolk-broads.co.uk/downloads/bmc1500L-diesel-workshop-manual.pdf

[Tony Brooks]

I'm thinking it might be a good idea to start thinking about changing the above, my engine has about 2,500 hours on it and the boat is around 28 years old. I wonder if anybody has done this job, and whether there are any hints and tips etc they could pass on? Alternatively, anyone in the Rugby area who could be recommended to do the job in case I decide it's better left to an expert?

 

The main difficulty will be in gaining good access to the front of the engine on a typical narrowboat. Maybe best to think about cutting a large trap in the bulkhead.

 

Changing the chain will require the sprockets to be slid forwards so make sure you can get at the timing marks in case the crankshaft moves whilst you are working on it but if you line the marks on the sprockets up before you move them hopefully nothing will move.

 

Undo the crankshaft nut. This is likely to be FT. You may have to remove the starter so you can jamb a flywheel tooth with a big screwdriver. BMC had a special service tool that was a crude hexagon ring spanner designed to be hit with a large hammer. Can't rem,ember if its possible to put a large ring spanner or socket and breaker bar on it and lodge the "handle on an engaging bed and hit the starter with stop pulled. Hands and feel very well out of the way.

 

Timing cover held on by a ring of bolts (new gasket required) and you may as well fit a new oil seal.

 

Slide off the crankshaft oil thrower and note how you need to refit it.

 

Cam shaft sprocket nut, again FT and with a lock tab. I suspect that even if you manage to undo the crankshaft nut this one will require a flywheel tooth jambing - probably a two man job.

 

Tensioner held on by two bolts with a lock tab. It is easier if you can get the hexagon screw plug out of the bottom of the tensioner body so you can use an allen key to wind the tensioner back to the lock position. Otherwise it is all likely to fly apart. Just try to hold the rubber block into the body when you take it ff if you can not wind it back.

 

Then its slide the sprockets forward (mainly the camshaft one) to get the chain off, a pry bar two two may be helpful.

 

Refitting is the reverse apart from ensuring the timing marks on the sprockets are correctly aligned.

 

Is the chain rattling? If not I would tend to leave it alone but its your boat so do what makes you happy.

Edited March 26, 2015 by Tony Brooks

[Chalky]

I'm about to change the timing chain on an MGB, It's a B series petrol engine so this is probably completely wrong for a diesel. On the MG the bodge for removing the crank shaft nut is to disconnect the distributor (so it won't start) put the correct socket and T bar on the crank nut leaning the T bar against the longitudinal. You then crank the engine. This either a) loosens the nut or b ) catapults the t bar across the garage. I've always achieved A.

 

I bought a new duplex timing chain, tensioner, 2 sprockets and all of the lock tabs etc from the MGBhive in Wisbech. Cost was £37 + postage. Check the sprocket key ways are cut in the same place if you use this source.

Edited March 25, 2015 by Chalky

[bizzard]

It's also worth while when refitting the chain cover to fit it up with new gasket, grease the seals lip, screw in bolts but leave them loose, fit pulley. Turn the engine over a few times to centralize the oil seal on its pulley track. Push case firmly in with one hand to hold it centralized whilst nipping up a couple of opposite bolts, carry on systematically tightening the bolts. Failure to do this may cause a little oil leak or cause unequal seal wear. Once some of the bolts are tightened the pulley can be removed to tighten any awkward ones behind the pulley and then it can finally be refitted.

Edited March 25, 2015 by bizzard

[Southern Star]

 

 

 

Is the chain rattling? If not I would tend to leave it alone but its your boat so do what makes you happy.

Thanks for all of the replies, can I just focus on this one thing for now? No, the chain isn't rattling, I had read that 30 years is about the lifespan of a timing chain and was thinking it might be best to change it as a precaution as it is coming up to that age and I know little about the boat's service history. It does tend to smoke on start-up from cold, which I believe is a symptom of timing chain wear. Will a timing chain always start rattling before its demise?

[Guest]

Is this engine a interference engine or a non interference engine?

[bizzard]

Is this engine a interference engine or a non interference engine?

Well let me see, the alternator may need a suppressor so as not to cause television interference.

[Southern Star]

Is this engine a interference engine or a non interference engine?

As far as I'm aware, the only non-interference engines are (some) petrol engines?

[Tony Brooks]

Two items added to my task list above.

[Stilllearning]

As Tony has said, if it isn't rattling, leave it alone. If on starting it smokes a bit, probably white smoke? then it clears, then it is a fairly normal BMC, and again, leave it alone. As far as i know ( which isn't far ), timing chains don't tend to cause smoke on start up.

[Tony Brooks]

As Tony has said, if it isn't rattling, leave it alone. If on starting it smokes a bit, probably white smoke? then it clears, then it is a fairly normal BMC, and again, leave it alone. As far as i know ( which isn't far ), timing chains don't tend to cause smoke on start up.

 

 

Well, I suppose they could because when they stretch they will retard the injection timing a little but there is enough adjustment on the injector pump to sort that out.

 

The same applies to the injector pump drive skew gears there their lubrication is somewhat marginal and thus have a propensity to wear if their strain rand jet are not kept clean. If the OP has not already done so I would far rather he removed, checked and cleaned the skew gear lubrication jet and strainer.

[Dutchie]

 

 

 

Is the chain rattling? If not I would tend to leave it alone

 

Tony do you mean with this, that the moment for renewal the timing chain is wait for rattling ?, correct me if i,m wrong , my engine in my boat has a very bad access on the front , the chain of my T90 isn't rattling and the engine runs very nice ..

Edited March 29, 2015 by Dutchie

[dccruiser]

I'm thinking it might be a good idea to start thinking about changing the above, my engine has about 2,500 hours on it and the boat is around 28 years old. I wonder if anybody has done this job, and whether there are any hints and tips etc they could pass on? Alternatively, anyone in the Rugby area who could be recommended to do the job in case I decide it's better left to an expert?

I have an original workshop manual from my days with a bmc if you are interested ... can either scan and email all the relevant pages, or happy to part with the manual for a reasonable offer + p and P

 

Rick

[RLWP]

http://the-norfolk-broads.co.uk/downloads/bmc1500L-diesel-workshop-manual.pdf

 

Richard

[Tony Brooks]

 

Tony do you mean with this, that the moment for renewal the timing chain is wait for rattling ?, correct me if i,m wrong , my engine in my boat has a very bad access on the front , the chain of my T90 isn't rattling and the engine runs very nice ..

 

Personally I would leave it alone, especially as it is still running well. Once it starts to rattle its a different matter just in case it jumps a tooth or comes through the timing cover (see an earlier post). Messing with things that are working well all too often ends up with more problems than it solves - especially if access is a pig.

[Dutchie]

Thanks for the good advice , i,m leave it alone , and use my ears in the upcoming time , i,m getting a new chain, spanner and oil seal in spare for sure

i,m also thinking to made an inspection cover in the front off the engine for servicing and check the timing .