1.5 BMC Crank oil seals - please help!

M

MANXPEDRO

Well-Known Member
Joined
19 Sep 2007
Messages
80
Location
RAMSEY, ISLE OF MAN
www.ramseybedandbreakfast.com
Hi everybody! After the drive plate failing, between the flywheel and gear box, I took the box home and overhauled it while awaiting the new plate. I then noticed, a slight weeping of sump oil coming from under the flywheel. So I thought, while the box is out, I'd pop a new gasket in it. I spoke to a chap in lancing marine, but like me, our manuals were not the best. He sent me a seal, but looks a bit on the big side.

I've now lifted the engine out, and it's on deck.

Where the flywheel mounts, there's a flange with bolts to hold it on. The flange has no key way or splines. This flange is hiding the seal.
The front end, the pulleys have to come off, as the crank comes out through the timing chest cover, so I imagine should be easy enough.

So my question is, do I need to remove the sump and lower the main bearings, draw the crank down a bit to expose these seals?

Please help me, I'm at my wits end with the bloody thing!!! It took me a day an a Half just to get the flywheel off!!!
So before I give in and throw the whole lot over the side, and replace it with pedals (I'd be the only person with a 30' dive pedal ow !!!!!
 
I dont recall the BMC having half seals at the rear main or a seal with a locating flange. Mind you it is well over 20 years since I saw one. I recall a straight forward viton or neoprene lip seal. Try drilling and a couple of self tappers to get a grip on it.
 
I have the manual for the Tempest conversion of the BMC 1.5. It does not show a rear crankshaft oil seal at all, only the forward one. No mention of the rear seal in the rebuild text. The flange is part of the crankshaft forging, so no conventional lip seal is going to fit. Looks like it relies on the thrower only.
 
tinkicker0 said:
Ahh from the dim recesses of the mind I recall some motor or other having a thrower and a scroll at the back end. Maybe the BMC is it.
Click to expand...

That's correct, like you I haven't had much to do with them for a while now but I seem to remember the very last few made had a lip seal like the 1.8 not certain if these were the Indian made ones or not.
You never seem to stop them leaking no Matter what you do.
I have enough bits in the garage to build one good one fully marinised, one of those spare time projects if I ever get it done.
 
Hi Manxpedro
Re your BMC1.5D the original engine relied on a scroll on the crankshaft just behind the rear main and the main bearing cap ran close to the scroll winding the oil back into the sump. Any wear in the bearings allowed the cap to make contact to the scroll resulting in wear and a rear main/flywheel leak. It was possible to build up the cap and re-machine it to its original spec but the other option (don't know if still available ) was an after market product with a proper oil seal carrier and seal which came as a kit but required a fair amount of precision machining to the cylinder block to achieve the end result. Might be worth trying ASAP spares as I think they were a possible source of the kit.
Best of luck
David
 
The canal boys are the ones to speak to. Lots of these engines still doing yeoman service in narrow boats.

I rebuilt a few back in the days when I was a BMC dealer and also raced a 1.8 B series. I can not recall ever seeing a scroll seal, but maybe only saw later ones. The ones I worked on had a backplate with lip seal.
 
Thanks for all your advice fellas! Today, I got the big lump flipped over and the sump off. And there, was the oil flinger and scroll. Like somebody said above, check the main bearings. I removed to caps to see slight wear, nothing major, however I thought with the engines pulled this far to bits, its not an expensive job to replace them, so hopefully this could resolve my slight weep, which I should really have just tolerated!!!!!
So, thanks again for all your help, I could just do with a hand throwing the lot back together! Any takers?? Im afraid im so skint at the minute, I can only pay in tea and jaffa cakes!!!
Pedro.
 
I guess you're sorted now, but if you have any BMC problems in the future I would suggest you contact Calcutt Boats at Stockton, Near Southam, Warwickshire on 01926-813757. They are renowned BMC specialists on the inland waterways.
Hope that helps.
Jon
 
aquapower said:
That's correct, like you I haven't had much to do with them for a while now but I seem to remember the very last few made had a lip seal like the 1.8 not certain if these were the Indian made ones or not.
You never seem to stop them leaking no Matter what you do.
I have enough bits in the garage to build one good one fully marinised, one of those spare time projects if I ever get it done.
Click to expand...

Yes I know I'm digging up an old thread, but that's better than starting a new one on the same subject.

Question I have is about parts, so here goes,
Where the heck, other than a scrap yard, so I find a pulley vibration torsional damper, and although I know its unlikely where can a buy a new crankshaft ??
If anyone who has worked on BMC marine diesels in the past, it would be good to know roughly what needs to done done in terms of installing a new crankshaft, and what pitfalls to expect ??
 
Croftie said:
Try asking in Canal World loads of owners/knowledgeable people in there re BMC 1.5's
Click to expand...
I've already asked, but none of the members have found a company like Gates who make top of the range vibration dampers for a whole range of different cars and trucks, that makes one that will fit a BMC 1.5, and for some odd reason the companies that recondition worn out or split pulley damper bearings, are willing to try and recondition one for a BMC of any type. So it's a marine and car scrap yard search if you have one that must be replaced.
My BMC 1500D is over 60 years old, but luckily I can find cheap parts for every single part, EXCEPT the pulley torsional vibration damper, and the 2 main parts companies that sell a lot of parts for them, have no idea where one can be obtained either.
 
New cranks are available nowadays but 10 years ago they were not. We can thank all the hindustan diesel taxis in India for manufacturing lots of very cheap engine parts for the bmc. The crankshaft pulley with the insert is about the only item I've not been able to find.
 
Rappey said:
New cranks are available nowadays but 10 years ago they were not. We can thank all the hindustan diesel taxis in India for manufacturing lots of very cheap engine parts for the bmc. The crankshaft pulley with the insert is about the only item I've not been able to find.
Click to expand...
Yep British Leyland did get some things right, BUT most of the early Austin Taxis that had the 1500D, had a normal pulley bearing with no rubber bits. They are cheap to make, but a torsional damper bearing is not.
Everyone thinks that the good quality non OEM parts are all made in China, BUT many of them are in fact still made in India, with a few odds and ends from Coventry.
I upgraded the oil and CAV 296 secondary fuel filter with spin on filter conversion kits from ASAP, (And India). I replaced the original 55A alternator, a Lucas A127 with a 70A far Eastern, (No marks), 70A look alike. That's about as far as you can push a single toothed belt before it slips. The bigger 120A ACR alternators need a larger multi grove pulley, and the cost of doing that is more than a new alternator. Don't need more than 70A max anyway, and I've already purchased 70A heavy duty cables for the alternator, inverter and charger side of things, so a heavy duty 120A alternator or a second 55A one would be expensive in wiring terms.
 
You must log in or register to reply here.

Other threads that may be of interest

ianc1200
Sureseal shaft seal.
2
Replies
20
Views
536
ianc1200
ianc1200

Share this page

Top