Engine reboring

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Graham_Wright

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I have acquired a BMC 1.5 litre diesel engine which is very clean but worn.

The cylinders are outside the ultimate rebore limit and, presumably, need liners.

This is not something I wish to do myself.

Anybody had any such experience, costs, time etc?
 
Sorry Old Bum
Fitting liners to a worn iron block is quite normal. The block is bored out, liners hydraulicly pushed in and then machined out to the original bore size.
I had this done to a 4-108 when two bores were damaged and only standard pistons were available. IIRR it was Perkins standard practice.

How it compares to finding another block in decent nick is something else.

Not had this done in UK, so price not helpful, but in Portugal were it was V reasonable.
 
Graham_Wright said:
The cylinders are outside the ultimate rebore limit and, presumably, need liners.
Click to expand...

I was trying to find out if the BMC 1500 Diesel had wet or dry liners but apparently neither. But I read:

But the B-series block and head were slightly larger in both length and width and the block had thicker cylinder wall castings (making the new engine heavier than the A40 motor). This was to allow room for enlargement of the cylinder bore to provide the larger capacities foreseen by BMC. The stroke was retained at 89 mm (3.5 in) and was never altered. Originally of approximately 1.2 Litre capacity, later displacements ranged widely from 1.2 L to 2.4 L, the latter being an Australia only production six-cylinder variant. The most common engine sizes were 1.5 L and 1.8 L and saw service in a number of vehicles.

I wonder if you could bore it out and turn it into an 1800cc? Of course there would be the cost of the boring and new pistons/rings which would be quite significant. But the diesel engine was made under license in India so they may still be using the motor in their taxis!!i
https://en.wikipedia.org/wiki/BMC_B-series_engine
 
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Is it not possible to find a less worn engine and swap the marinising parts across?

Or, can some other pistons be found which would allow boring it further?

Alloy cylinders get metal spraying repairs and hard coatings. I assume that's not an option, but I'd expect it to be in 3 figures per bore anyway?
 
coopec said:
I was trying to find out if the BMC 1500 Diesel had wet or dry liners but apparently neither. But I read:

But the B-series block and head were slightly larger in both length and width and the block had thicker cylinder wall castings (making the new engine heavier than the A40 motor). This was to allow room for enlargement of the cylinder bore to provide the larger capacities foreseen by BMC. The stroke was retained at 89 mm (3.5 in) and was never altered. Originally of approximately 1.2 Litre capacity, later displacements ranged widely from 1.2 L to 2.4 L, the latter being an Australia only production six-cylinder variant. The most common engine sizes were 1.5 L and 1.8 L and saw service in a number of vehicles.

I wonder if you could bore it out and turn it into an 1800cc? Of course there would be the cost of the boring and new pistons/rings which would be quite significant. But the diesel engine was made under license in India so they may still be using the motor in their taxis!!i
https://en.wikipedia.org/wiki/BMC_B-series_engine
Click to expand...

That seems entirely feasible. I need to find out if the original pistons would fit the rebored standard bore (i.e. Ø73.01) or whether I would need replacements. If the bores are already at top limit, would the pistons be bigger than original or do bigger rings sort out the difference.

If I need replacements, they may as well be for the 1800 version, I would not then have the cost of the liners.

Would the injector pump need to modified or changed for a different one?

There is a local regrind specialist I will visit for a chat.
 
Graham_Wright said:
That seems entirely feasible. I need to find out if the original pistons would fit the rebored standard bore (i.e. Ø73.01) or whether I would need replacements. If the bores are already at top limit, would the pistons be bigger than original or do bigger rings sort out the difference.
If I need replacements, they may as well be for the 1800 version, I would not then have the cost of the liners.
Would the injector pump need to modified or changed for a different one?
There is a local regrind specialist I will visit for a chat.
Click to expand...

You can't use the pistons out of the 1500cc motor in a block that has been re-bored to 1800cc. The rings could not possibly take up the gap, When a motor is at operating temperature there is not much gap at all between the top of the piston and cylinder wall.

You definitely would need pistons and rings for an 1800cc motor. But would the inlet and exhaust valves be enlarged and what modifications to the injector pump etc would be required you'd have to talk to someone "in the know".

I didn't think the BMC motor had liners? I used to have a 2.4L version of the motor and I'm sure it didn't have liners (I'd be surprised if I am wrong)
 
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Graham_Wright said:
I have acquired a BMC 1.5 litre diesel engine which is very clean but worn.

The cylinders are outside the ultimate rebore limit and, presumably, need liners.

This is not something I wish to do myself.

Anybody had any such experience, costs, time etc?
Click to expand...

Have been doing quite a bit of messing with 2 perkins 4108s with various issues.
I did find it was more expensive using specialists for each task rather than getting a rebuilding specialist to do a complete top bottom or both rebuild
 
Calcutt were mentioned earlier. They sell liners for the 1.5 engine for £35 each, which seems very reasonable. Also worth talking to ASAP, as they carry a lot of BMC spares not listed on the website. As TQA says there are hundreds of these engines in use in canal boats, so spares are widely available.
 
vyv_cox said:
Calcutt were mentioned earlier. They sell liners for the 1.5 engine for £35 each, which seems very reasonable. Also worth talking to ASAP, as they carry a lot of BMC spares not listed on the website. As TQA says there are hundreds of these engines in use in canal boats, so spares are widely available.
Click to expand...

I strongly agree with you that Graham should talk to Calcutt to sort out options.

Now what am I doing wrong? I went to Calcutt website
http://calcuttboatsshop.com/epages/...a6cb0f-3e0f-4132-9636-974f7502e04d/Categories
but I can't see any mention of sleeves for £35 each.

I think Graham should sharpen his pencil as the whole exercise could be costly. On top of the £35 for sleeves he'd have to pay for boring the block (I think there was a figure mentioned for that earlier)

NOTE Maybe I'm wrong. Every BMC B Series motor I've come across has been a cast block with cylinders cast into the block. But then I've just read in a thread
"Has anyone in the MGB world ever come across a 5-main engine with factory installed cylinder sleaves?"

Negative on the sleeved 5-main. Lots of the 3-main Magnette/Austin/Wolseley blocks were factory sleeved for whatever unknown reason.
 
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coopec said:
I strongly agree with you that Graham should talk to Calcutt to sort out options.

Now what am I doing wrong? I went to Calcutt website
http://calcuttboatsshop.com/epages/...a6cb0f-3e0f-4132-9636-974f7502e04d/Categories
but I can't see any mention of sleeves for £35 each.

I think Graham should sharpen his pencil as the whole exercise could be costly. On top of the £35 for sleeves he'd have to pay for boring the block (I think there was a figure mentioned for that earlier)

NOTE Maybe I'm wrong. Every BMC B Series motor I've come across has been a cast block with cylinders cast into the block. But then I've just read in a thread
"Has anyone in the MGB world ever come across a 5-main engine with factory installed cylinder sleaves?"

Negative on the sleeved 5-main. Lots of the 3-main Magnette/Austin/Wolseley blocks were factory sleeved for whatever unknown reason.
Click to expand...

I googled bmc 1.5 liners and up it came. My mistaken memory though, they are £35.10, not £35.00
 
vyv_cox said:
I googled bmc 1.5 liners and up it came. My mistaken memory though, they are £35.10, not £35.00
Click to expand...

But, but! They would be "wet liners" and we know Graham's motor is not a sleeved motor because it has been re-bored to the limit. (Of course you don't re-bore sleeved motors because you replace the sleeves)

We both agree that Graham should get expert advice and Calcutt sounds like a good start.

Actually here is a dry liner for $38 but there would be the cost of re-boring the motor to take the dry sleeve. If the pistons were still OK (I doubt it) they could be re-used.


Temp liner.JPG
 
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coopec said:
You can't use the pistons out of the 1500cc motor in a block that has been re-bored to 1800cc. The rings could not possibly take up the gap, When a motor is at operating temperature there is not much gap at all between the top of the piston and cylinder wall.
Click to expand...

You misread;- "That seems entirely feasible. I need to find out if the original pistons would fit the rebored standard bore (i.e. Ø73.01) or whether I would need replacements. If the bores are already at top limit, would the pistons be bigger than original or do bigger rings sort out the difference."

I don't know if the previous rebore(s) required bigger pistons or if rings would fill the gaps.


You definitely would need pistons and rings for an 1800cc motor. But would the inlet and exhaust valves be enlarged and what modifications to the injector pump etc would be required you'd have to talk to someone "in the know".

I didn't think the BMC motor had liners? I used to have a 2.4L version of the motor and I'm sure it didn't have liners (I'd be surprised if I am wrong)
Click to expand...

Reading around the subject, it seems BMC built the block with expansion in mind. Apparently, the Australian version bored to 2.2 litres. The blocks were not fitted with liners. I take your point about the valves and pump.

There is a local company who specialise in rebores and I will visit for a chat.

I have considered asking Calcot or similar to refurbish but I know that if I do the necessary myself with local facilities, I can be sure of the quality. I know that Calcot have a good reputation but the engine bought from Norris was supposedly reconditioned. With compression readings half what they should be, I doubt that and there is a "clank" that may be normal but I doubt it. The engine has only done maybe 100 hours since originally fitting it.
 
Graham
The engine that was 2.2L was actually 6 cylinder. (I used to own one when I wore a younger man's clothes. It was a firecracker and I was only ever beaten once off the mark and that was by a V8 American car. But as he passed me I could see smoke coming from under his bonnet and shortly later he pulled off to the side of the road in a cloud of smoke!)

I think you are wise getting experts involved. I've looked back at my previous comments and I can't see where I gave you this link.

https://www.charnleys.com/part/leyland-light/12h524/cylinder-liner

https://www.charnleys.com/contact

I'm not recommending them: just giving you the link.

I haven't checked lately but what would a new 1.5L marine diesel cost these days?(I bet the price is hideous)

Good luck
 
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I had a 1986 BMC 2.5 Diesel engine (Thornycroft) in my boat and thought about finding a spare engine, having it bored with new pistons, head skimmed and new valves etc and fitting it. But I found that spare parts were extremely difficult to obtain. I also wanted a Water Pump in case my existing one needed replacing but I could not find one anywhere. I could get the existing one repaired but to find one to have as a spare proved impossible.
As an ex-engine repairer who worked on BMC engines from the 1960's - the 1980's I was suprised how few engine parts are available, unlike Perkins.
The lack of spares for my 2.5 diesel was one of the reasons I decided to sell my boat.
 
Jim@sea said:
I had a 1986 BMC 2.5 Diesel engine (Thornycroft) in my boat and thought about finding a spare engine, having it bored with new pistons, head skimmed and new valves etc and fitting it. But I found that spare parts were extremely difficult to obtain. I also wanted a Water Pump in case my existing one needed replacing but I could not find one anywhere. I could get the existing one repaired but to find one to have as a spare proved impossible.
As an ex-engine repairer who worked on BMC engines from the 1960's - the 1980's I was suprised how few engine parts are available, unlike Perkins.
The lack of spares for my 2.5 diesel was one of the reasons I decided to sell my boat.
Click to expand...

Was the 2.5 the same block as 1.5/1.8?
 
No, it couldn't be. As far as I know the BMC "B" Series was only stretched to 1800cc. By going from 4 cylinder to 6 cylinder it was 2,2L
 
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