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BMC 1.5 Crankshaft Bolt


MrC

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1 minute ago, TNLI said:

Great thanks for that, the engineer already knows about the front and back, but I will mention the cam sprockets and timing chain.

 

So how long a job would you and the other BMC experts allow for removal ??

With the engine out and an air wrench, about 25 minutes.

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Just now, TNLI said:

Great thanks for that, the engineer already knows about the front and back, but I will mention the cam sprockets and timing chain.

 

So how long a job would you and the other BMC experts allow for removal ??

 

Assuming the engine is out of the boat, in an easy working positon and there are no problems like damaged threads or hexagons  I would hope to have the crank in less than two to three hours. Less if I had an electric or air impact wrench/ratchet.

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I had a Russel Newbery E6 that dismantled itself............had a big plate the length of the crankcase that rods pistons and crankshaft could be removed without lifting the engine off its bearers.............which was fortunate because it was a pos.....

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2 hours ago, Tony Brooks said:

I can't help thinking that if you are going to the trouble of taking the crank out you might as well have the head off and valves out and do a complete job.

The top end rebuild was all done to a high standard with all receipts before I purchased the engine, BUT the bottom end job was not finished. That is why I have been asking a lot of questions about the crankshaft and pulley bearing issue. 

 

I managed to visit the specialist crank company this afternoon and was pleased the crank had already been removed, so I was wasting everyone's time to some extent, as they had made more progress than I expected.

 

  The crank shaft was inspected and although the dye test machine did not show up any cracks, the shaft journal wear check figures were out of limits, and it is now in the queue to be reground. Alas the senior engineer who removed and tested the crank was off on a long weekend, but their other main specialist said the main bearings that were replaced by the previous owner, were already visibly worn, so will need replacing again, although that is required if the crank is reground anyway. Unfortunately the engineer I spoke to did not know anything about the condition of the pulley torsional damper, (If it has one), but I hope the fact they are going to reassemble the engine means it's good. Touch wood on that score!

 

Once the crank and main bearings job has been done, the engine will be moved back to the garage without the gearbox, as that has to be inspected by the experts even though it seems to function correctly. So now for the big question:

Can I run the engine without the gearbox attached if I blank off the oil feed and return, as I want to finish the wiring job ???

 

 

 

 

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1 minute ago, TNLI said:

The top end rebuild was all done to a high standard with all receipts before I purchased the engine, BUT the bottom end job was not finished. That is why I have been asking a lot of questions about the crankshaft and pulley bearing issue. 

 

I managed to visit the specialist crank company this afternoon and was pleased the crank had already been removed, so I was wasting everyone's time to some extent, as they had made more progress than I expected.

 

  The crank shaft was inspected and although the dye test machine did not show up any cracks, the shaft journal wear check figures were out of limits, and it is now in the queue to be reground. Alas the senior engineer who removed and tested the crank was off on a long weekend, but their other main specialist said the main bearings that were replaced by the previous owner, were already visibly worn, so will need replacing again, although that is required if the crank is reground anyway. Unfortunately the engineer I spoke to did not know anything about the condition of the pulley torsional damper, (If it has one), but I hope the fact they are going to reassemble the engine means it's good. Touch wood on that score!

 

Once the crank and main bearings job has been done, the engine will be moved back to the garage without the gearbox, as that has to be inspected by the experts even though it seems to function correctly. So now for the big question:

Can I run the engine without the gearbox attached if I blank off the oil feed and return, as I want to finish the wiring job ???

 

 

If you mean the feed and return for the gearbox oil cooler then don't blank it, just in case  there is a leak between the oil and water parts. It is the gearbox that   supplies the oil to the cooler so no gearbox = no oil.

 

So yes, a song as you get nothing caught in the flywheel you can run the engine but make sure it can't turn over by torque reaction when you start or rev it.

 

 

 

 

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37 minutes ago, Tony Brooks said:

 

If you mean the feed and return for the gearbox oil cooler then don't blank it, just in case  there is a leak between the oil and water parts. It is the gearbox that   supplies the oil to the cooler so no gearbox = no oil.

 

So yes, a song as you get nothing caught in the flywheel you can run the engine but make sure it can't turn over by torque reaction when you start or rev it.

 

 

 

 

If the gearbox is not fitted the oil cooler is not an issue, as it will not be used. I was thinking of just connecting the circulating pump to a bucket, with the warm coolant from the top outlet pipe feeding the same bucket. I was just concerned about the oil circuit, but will have to look at a diagram of the connections if any between the engine and gearbox. From your comment, there is no oil feed from the engine to the gearbox other than the oil change pump one.  

 

So any chance of explaining what you mean by torque reaction from the flywheel ?? 

 

The other issue is that there are several companies that will inspect and supply a report on the condition of the box in my local area, but as I'm not familiar with the TMP 100, what roughly should be checked to see if it should be rebuilt ?? I've read the manual but it does not really ID how to figure out when such a box should be reconditioned. 

  So the key question is what symptoms apart from difficulty shifting into or out of gear and obvious vibration issues would indicate it needs to be reconditioned ?? For example, when you start to get oil leaks from the main prop shaft and engine input bearings, the fact the seals are starting to fail often indicates the associated bearing are also going to need changing.

 

  Also are there any special tools required when installing the gearbox again, in terms of how it is aligned etc ?? II did have a look at how one was reconditioned, and it did not look like there were any special tools involved in terms of bearing pullers etc. Or is that video missing something ??

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I thought you had a PRM gearbox but am not trawling back through all your posts to find the photos.

 

I have yet to see a 1.5 with any oil connection between engine and gearbox.

 

Unless the engine is fixed to the beds the whole block would be  happy to spin around the crankshaft. The  flywheel has inertia which means it is reluctant to speed up so when the engine accelerated so the flywheel tries to stay at its previous speed causing the whole engine to try to spin in the opposite direction of rotation. That is torque reaction. If you watch a flexibly mounted engine you will see it twist on its beds as it accelerates.

 

Hydraulic gearboxes rarely vibrate but the bearings may whine. The usual failure mode is slipping clutches, typically either ahead or astern, rarely both. The bearings would be screaming if they were worn enough to allow oil leaks, simply worn seals would be a more likely cause. A failing drive plate might cause a degree of vibration but noise out of gear at idle is more likely.

 

There are normally no pilot bearings in the flywheel for most marine boxes of this size and technology so as long as the drive plate has been correctly drilled for its mounting screws all you have to do is ensure the splines are lined up. It is a bit harder on a hydraulic box because you can't put it in gear so the input shaft twists as you twist the box but there is usually no great problem.

 

No comment on special tools but you might have to measure the end float on the shafts so you can shim the bearings. This is a general comment because It is not clear what box you have.

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1 hour ago, Tony Brooks said:

I thought you had a PRM gearbox but am not trawling back through all your posts to find the photos.

 

I have yet to see a 1.5 with any oil connection between engine and gearbox.

 

Unless the engine is fixed to the beds the whole block would be  happy to spin around the crankshaft. The  flywheel has inertia which means it is reluctant to speed up so when the engine accelerated so the flywheel tries to stay at its previous speed causing the whole engine to try to spin in the opposite direction of rotation. That is torque reaction. If you watch a flexibly mounted engine you will see it twist on its beds as it accelerates.

 

Hydraulic gearboxes rarely vibrate but the bearings may whine. The usual failure mode is slipping clutches, typically either ahead or astern, rarely both. The bearings would be screaming if they were worn enough to allow oil leaks, simply worn seals would be a more likely cause. A failing drive plate might cause a degree of vibration but noise out of gear at idle is more likely.

 

There are normally no pilot bearings in the flywheel for most marine boxes of this size and technology so as long as the drive plate has been correctly drilled for its mounting screws all you have to do is ensure the splines are lined up. It is a bit harder on a hydraulic box because you can't put it in gear so the input shaft twists as you twist the box but there is usually no great problem.

 

No comment on special tools but you might have to measure the end float on the shafts so you can shim the bearings. This is a general comment because It is not clear what box you have.

No idea why I typed in TMP 100, when it is definitely a PRM 100, and I have corrected that in the previous post. 

 

Thanks for the warning about the torque reaction, as I'm not used to engines with significant flywheel inertia, so I'm kind of thinking about installing it on the boat before testing it, as I would need to have a much better mounting system on the present pallet, otherwise I'm going to have to make up some dummy mounting blocks for the engine mounts. 

 

A final question about the PRM 100, is about how difficult it would be to remove or install it without lifting the entire engine. I plan to have very good access all around the engine in terms of all of the panels being made in such a manner that I can remove them, BUT with some engines it's difficult to align without being able to see its position from below, or there is no room to uncouple it before running out of distance to move the prop aft, although if the boat is out of the water I can remove the rudder itself. So anyone removed or refitted a PRM without lifting the engine out ??

  

 

  

Edited by TNLI
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I have had all sorts of gearboxes off with the engine still in the boat but often you need to lift the back of the engine to get the rear mounts off (I think you  have non-standard mounts on the gearbox) and/or to lift the box high enough so it clears the prop shaft half coupling.. Just be aware that I think your gearbox is cast iron so will be heavy.

 

If it is sitting on a pallet on a full length sump just rope it down well onto the pallet and don't rev it too fast, let the speed build up gradually.

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41 minutes ago, Tony Brooks said:

I have had all sorts of gearboxes off with the engine still in the boat but often you need to lift the back of the engine to get the rear mounts off (I think you  have non-standard mounts on the gearbox) and/or to lift the box high enough so it clears the prop shaft half coupling.. Just be aware that I think your gearbox is cast iron so will be heavy.

 

If it is sitting on a pallet on a full length sump just rope it down well onto the pallet and don't rev it too fast, let the speed build up gradually.

Thanks Tony that's good to hear that it's not too tricky in alignment terms. I will have plenty of room in terms of lifting the box. Obviously when I am in effect designing the engine bay enclosure, I really want to try and make it easy to remove if the need arises. Some boats I crewed on, or skippered were a serious nightmare in engine removal terms, and many were in engine bays that were far too tight for basic maintenance to be easy, as the designers do not consider the engineering side very much, and are only interested in maximum cabin space. 

  In many ways I'm pleased the crank et al are going to be reconditioned and installed by the best company in the area, as I know if you start with a sound block and look after it correctly, it should last a very, very long time.

 

The one thing I would warn anyone buying a so called reconditioned BMC or planning on doing the job themselves, is that very few engines are restored correctly, as it can prove too expensive, and I would never pay serious money without the crank and main bearings being done by the type of company doing mine. It's always the parts you can't inspect that get overlooked, and a 3 month warranty offered by some companies like Calcutt is just no good. 

 

PS: The engine bay is probably going to be the most difficult part of the build in some ways, so I'm going to get a professional carpenter I know to help me, as it has to be fairly watertight, so it's going to be a rather tricky task. 

 

 

Edited by TNLI
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1 hour ago, Tony Brooks said:

I hope not airtight as well, the engine needs huge amounts of air when it is running.

I plan to fit a pair of intake vents than can be closed and a fan to blow air outside to cool the bay area. The RNLI system uses a lead pendulum to shut the main engine intakes that is a real odd looking item. 

  In reality I would try to avoid ever using the engine in heavy weather anyway, and just use a storm jib and small trysail, (Mini mainsail), the RNLI offshore boats are rigged to auto cut and start if they roll. Superb but very expensive systems. 

 

Oddly enough if you look at the used oil analysis I posted, the Lead figure was 16, when the average should have been around 2, although it does vary with engine type.

So although UOA results are normally higher in some wear metals when the rings and bearings are changed, that high figure did indicate the main bearings were as the inspector said, not good. The chap that sold me the engine got various companies to do the top end rebuild, but then got fooled by the odd fact the oil on the dipstick did not look too bad, when in fact it was in need of changing, the insoluble figure is near the limit. The good news was no sign of water or fuel in the oil. 

  The company doing the crank are also checking the timing chain and oil pump, although not heard of an oil pump failing for a BMC.

 

Thanks for the help, as you have allowed me to get a fairly good understanding of what to check and what issues can cause failures, which was partly why I decided the crank test should be done correctly.

I don't quite understand why the oil on the BMC dipsticks looks better than that from the oil change pump, as that could have fooled me into thinking it was OK in quality terms. 

 

Edited by TNLI
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  • 2 weeks later...
On 04/03/2020 at 10:21, Tracy D'arth said:

Correction.

 

You are correct Tony, some 1.5D have and some don't have a rubber damper, depends what they are originally out of.

Early ones in A60 cars did not have them I think. Perhaps BMC eventually discovered that the lack of a torsional damper broke the cranks when J4 PO van drivers thrashed them?

The bigger risk is the pulley fretting on the wood-ruff key, many do, leading to cracking in the pulley boss and lip seal destruction. Had several do this.

 

Apologies for the error and misinformation.   TD'

 

Now that's the type of post I like to read, so although I've supplied the bottom end rebuild experts with a lip seal, (It's in the bottom job kit), and they would check the pulley for damage, I will need to double check if I've ordered a new wood key. In fact I will copy this post from Tracy and send it to the engineering company, and ask again if my old donkey has a damper or not. Oddly enough my BMC had a new pulley boss fitted already, so might have suffered from the same issue as described. 

 So just to confirm the root cause of this potential issue, is it:

A/ Sudden large throttle movements

B/ Corrosion of, or around the key

C/ Over revving.

A canal boat engine is used in a very different way to a taxi, so I would be interested in the root cause of this potential fault.

 

Update on parts supply. ASAP and Calcutt parcels last Friday, (Some SAP parts on back order), and just received the Tractor Spare Parts Ltd box with a new oil pump and quote "7 MAIN BEARING SCREWS", they might look like bolts, but are defined as machine screws cos they have a slotted hex head, rather than a plain one. It's important to get the description right when you use a search engine on a company parts site, or the dreaded Goggle search. 

 

Question: Is there a special tool for the main bearing screws, cos the slotted heads are a non standard pattern, with only 4 slots, not 5 ?

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11 minutes ago, TNLI said:

 

Now that's the type of post I like to read, so although I've supplied the bottom end rebuild experts with a lip seal, (It's in the bottom job kit), and they would check the pulley for damage, I will need to double check if I've ordered a new wood key. In fact I will copy this post from Tracy and send it to the engineering company, and ask again if my old donkey has a damper or not. Oddly enough my BMC had a new pulley boss fitted already, so might have suffered from the same issue as described. 

 So just to confirm the root cause of this potential issue, is it:

A/ Sudden large throttle movements

B/ Corrosion of, or around the key

C/ Over revving.

A canal boat engine is used in a very different way to a taxi, so I would be interested in the root cause of this potential fault.

 

Update on parts supply. ASAP and Calcutt parcels last Friday, (Some SAP parts on back order), and just received the Tractor Spare Parts Ltd box with a new oil pump and quote "7 MAIN BEARING SCREWS", they might look like bolts, but are defined as machine screws cos they have a slotted hex head, rather than a plain one. It's important to get the description right when you use a search engine on a company parts site, or the dreaded Goggle search. 

 

Question: Is there a special tool for the main bearing screws, cos the slotted heads are a non standard pattern, with only 4 slots, not 5 ?

 

Machine screws have a thread all the way along the shank. Bolts only have a partial thread leaving some shank without a thread. they can be hexagon machine screws, dome headed, counter sunk and so on.  I still think that you have bolts because of the need to have a good fit in the cap. I have seen such things with indentations in the hexagon but I would not call them slots. If they are hexagons then the tool would normally be hex, bi-hex, or flank drive socket.

 

I suspect the man cause of pulley and pulley boss problems is the torsional oscillation that is normal and on ant reciprocating engine takes place throughout the rev range. Never seen corrosion around the key. A marine 1.5 should have a heavier flywheel or bulk ring added so its inertia that will slow the rate of rev up. As the 1.5 had a top rev speed of 4400 rpm I doubt it would ever get close to that in a displacement boat, in nay case the pumps were, I think, de-rated to a degree from automotive settings.

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5 minutes ago, Tracy D'arth said:

Don't understand slotted heads on bolts or machine screws. Do you mean slotted  as in for a screwdriver?  Hexagon head as for a spanner?  Recessed hex for allen keys? Recessed star drive?

 

I have seen bolts with shallow slot like indentations around the head but there is no way I could see any tool using them because they would be too shallow. I thought they might have designated a special steel because I think it was always on big end bolts.

 

I think a photo is needed.

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1 hour ago, Tony Brooks said:

 

Machine screws have a thread all the way along the shank. Bolts only have a partial thread leaving some shank without a thread. they can be hexagon machine screws, dome headed, counter sunk and so on.  I still think that you have bolts because of the need to have a good fit in the cap. I have seen such things with indentations in the hexagon but I would not call them slots. If they are hexagons then the tool would normally be hex, bi-hex, or flank drive socket.

 

I suspect the man cause of pulley and pulley boss problems is the torsional oscillation that is normal and on ant reciprocating engine takes place throughout the rev range. Never seen corrosion around the key. A marine 1.5 should have a heavier flywheel or bulk ring added so its inertia that will slow the rate of rev up. As the 1.5 had a top rev speed of 4400 rpm I doubt it would ever get close to that in a displacement boat, in nay case the pumps were, I think, de-rated to a degree from automotive settings.

Thanks Tony, so the correct tool is some special type of hex head socket that fits the 4 groves or cuts. They do have a partial thread and are marked CP and 8 on the top of the hex head, (No idea why it has an 8 on it as it should be an imperial (it measures 12.2mm) I called them main bearing screws because that is exactly what is written on the invoice. I did check that it is an imperial UNF thread by using a nut from my set of UNF BZP bolts and stainless nuts. 

 

A well designed marine diesel should be OK in crank shaft and other bottom end wear terms if you slam the go levers in either direction. I've been in some interesting weather conditions where myself or the Spanish fishing boat was working the throttles in a very rapid manner as we slowly headed home into a fairly bad gale. Nothing like the sea state in the film Perfect Storm, which was true, as a wave height recorder buoy on the nearby infamous Flemish Cap recorded a 90ft wave! 

 

  I would point out to the general BMC community that sudden movements of the throttle in either direction always cause some degree of additional wear, and if you have an engine that has not been reconditioned correctly, and that does mean having the crank removed for a professional inspection, and in my case a regrind, and new everything. The worst type of RPM change is the one that often occurs during a very cold start when the go lever is too far forward, as the sudden jump in RPM puts a seriously high load on the engine crank and assorted bearings, whilst the oil film does not function in terms of preventing direct metal surface contacts, even if it's an 0W30 there will be a few seconds when the oil film protecting the cylinder liners and rings does not really exist and some engine expert has decided to use an oil that lacks enough DZZP, (Zinc based compound that bakes onto any steel surface to protect it when the oil film fails, or the steel starts to corrode), to protect the bearings and rings etc. An incident of that type can cause the same amount of wear as more than 1000 hrs of normal under load use, or 100 hrs of battery charging at idle RPM.

 

One last parts order question, is to do with drive for the HP pump. My lists says the engineer needs a timing chain kit, so that means a new chain, tensioner and the double toothed sprocket. So, is there any other part you think might need replacing that can only be accessed with the engine lifted up and the sump et al removed ?? Obviously the oil pump is going to be replaced and the various locking tabs washers etc al, which are going to be ordered direct from the company making them, (Might be in India). ASAP are taking care of that back order, BUT will be charging me extra for the express padded envelope! 

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Unless you supply a photo I and I doubt anyone else can advise about the tool, but I THINK what you call slots has nothing to do with tightening or loosening. I THINK all you need is a standard socket.

 

If the Injection pump skew gears are worn it is  a lot easier to replace the camshaft and pump drive with the engine upside down and the sump off.

 

Which double toothed sprocket? The can sprocket or the crankshaft sprocket? If one is worn you can bet the other is as well. What is the key like that drives the crank sprocket?

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The sprockets, crank and cam are the same as 1800 MGB ones I am sure, I know that the 1.8D is the same parts. Bad form not to replace both and the chain on a well used motor. The teeth wear into hooks which cause extreme wear on a new chain.

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2 hours ago, Tracy D'arth said:

The sprockets, crank and cam are the same as 1800 MGB ones I am sure, I know that the 1.8D is the same parts. Bad form not to replace both and the chain on a well used motor. The teeth wear into hooks which cause extreme wear on a new chain.

Thanks, and I misread my own parts list, as although I now have the, "CRANK SHAFT GEAR BMC 1.5 & 1.8", alas the, "KEY CAMSHAFT SPROKET BMC 1.5 & 1.8", 

along with the, "TENSIONER ASSEMBLY TIMING CHAIN BMC 1.5", are on a June back order with ASAP, and they have asked their supplier in India if the parts are available at present, and the answer was no!

 

Any ideas where I might look for those 2 parts ?? 

 

I will try calling a few classic car and tractor parts companies tomorrow AM, but would be very interested in any companies that you know that might have those 2 parts in stock, or on backorder for early April ??

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