Author Topic: SR3 Rebuild  (Read 2318 times)

Orion

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SR3 Rebuild
« on: February 02, 2023, 06:49:51 AM »
Hi all! Only just joined so be gentle with me :)

Background
I recently bought an old Ketch which was fitted with a Lister SR3 engine that was working, albeit by a wing and a prayer, that then died in much the same way as the Bluesmobile did near the end of the movie. There was a loud crunch just as I was maneuvering the boat in position under the shiplift. During the initial restart I did manage to get it running again for a very short time until it became clear that all was not well. Upon inspection of the sump i found bits on the camshaft which apparently is not good!

My experience in mechanictary is less than zero, by which I mean I don't know what I don't know, however I did know a real marine mechanic who fell in love with the old motor and told me that if I could, I should keep it and rebuild it. So i armed with a shiny new spanner I set about stripping it down. For lots of details and photos please visit my blog myketchlife.com and click on the Engine Bay topic.

The engine is back together but obviously won't start because I'm still not a mechanic, however it does turn over nicely but is not firing at all which i believe is a fuel issue.
I had stripped down and cleaned the injectors during the rebuild, tried a couple of different methods of priming the fuel system and turned over the motor without the injectors connected as I don't have a spare pipe which is needed to prove the injectors out in the open (according to the parts manual I have). There didn't seem to be much fuel coming from the 2 of the fuel pumps and none coming from the third. As I had already proved that all the fuel lines are clear I stripped down the fuel pumps but cannot reinstall them yet as I am waiting on a new fuel delivery Vv as there was one missing! Also I am getting a complete new fuel filter as the original was only cleaned not replaced due to the age of the and unavailability of a replacement filter. Sorry about the long winded blurb but I was trying to think of what questions I may get asked.

Questions for the Brains Trust
Once I have the part and have re-installed the 3 pumps what is the best method of priming?
How much fuel should be coming from a fuel pump on each stroke?
I am unable to prove the fuel timing as there is no mark visible on The fly wheel so if this is the problem how do I fix the timing?
Is there anything else I should check before I do a restart?

Thanks in advance 8)

myketchlife.com
« Last Edit: February 07, 2023, 07:28:14 AM by Orion »

ajaffa1

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Re: SR3 Rebuild
« Reply #1 on: February 02, 2023, 07:16:00 AM »
Welcome to the forum Orion, first question: was this an SR3 or an SR3W (water cooled)? Second question, when a cam shaft breaks it usually does irreversible damage, what where the bits you found in the sump, did you replace the camshaft, the bushes what about the cam followers, did someone line bore the new bushes? Not an easy task for a non mechanic.
Assuming you have had all the above done correctly did you number the injector pumps and the shims that sit beneath them? If not you are going to have to spill time each injector pump to ensure it injects fuel into it`s cylinder at the right time. Then you can think about linking the injectors together and bleeding the fuel injectors.

One hell of a project you have taken on, hat off to you Sir!

Bob

cobbadog

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Re: SR3 Rebuild
« Reply #2 on: February 02, 2023, 10:23:12 AM »
Welcome Orion and well done so far.
Please dont be offended byh anything I mention it is given as ideas not criticism.
You mentioned that you stripped and cleaned the injectors. This is normally a job that requires specialty equipment when assembling and setting the working pressues, so this thought should go on a list of why it may not start.
In order to bleed the fuel system it is best to do it in stages. May sound silly but confirm you have fuel running freely out of the tank. Easiest way is to loosen the fuel line at the filter body if this is the 1st stage of fuel flow. Next bleed the filter housing. There should be a bleed screw on top of the housing. Next I guess the fuel goes to the 1st of the fuel pumps, ensure fuel runs freely to each pump in order and make sure there are no bubbles. So far this may be all gravity fed, if not you are going to get tired of pumping by hand.
Next with the throttle open wide start turning the engine overand see the small amount of fuel rise from the top of the pump. It is really just a dribble at this stage. Do this for all 3 pumps. Then disconnect the fuel line from all the injectors and crank again until you see the same amount of fuel come out of the fuel line with no bubbles, again on all 3 lines. Connect the fuel lines and attempt a start up but be ready to shut it down just incase.
This is how I bleed a diesel fuel system only mine are single cylinders and I have been able with one engine to remove the injector and connect it to the fuel line, crank it over and physically see the atomised spray. If you see this spray do not try to touch it as it is strong enough to impregnate into your skin and this is painful and dangerous to your health.
As I have never had to do spill timing I am unable to help but ajaffa1 - Bob, can help.
I found my timing marks on the outside flat section of the flywheel which showed a - mark for TDC and a lightning bolt for spark/spill timing I think. You will need to find TDC on compression then really clean up the rim of the flyweel at the 12 o'clock position and use a good light to help you see it. Once I found mine I really cleaned them up with a wire brush and filled the marks up using a white oil base marker pen.
Good luck and keep us informed.
Coopernook - the centre of our Universe.

ajaffa1

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Re: SR3 Rebuild
« Reply #3 on: February 02, 2023, 08:58:32 PM »
The timing marks are stamped into the outside face of the flywheel. They can`t be seen because of the bell housing that surrounds it, there should be a small viewing hole in the front of the bell housing. If I remember rightly there are marks for TDC and injector pump spill.

Bob

Orion

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Re: SR3 Rebuild
« Reply #4 on: February 05, 2023, 01:52:49 AM »
Welcome to the forum Orion, first question: was this an SR3 or an SR3W (water cooled)? Second question, when a cam shaft breaks it usually does irreversible damage, what where the bits you found in the sump, did you replace the camshaft, the bushes what about the cam followers, did someone line bore the new bushes? Not an easy task for a non mechanic.
Assuming you have had all the above done correctly did you number the injector pumps and the shims that sit beneath them? If not you are going to have to spill time each injector pump to ensure it injects fuel into it`s cylinder at the right time. Then you can think about linking the injectors together and bleeding the fuel injectors.

One hell of a project you have taken on, hat off to you Sir!

Bob

I'll have attached pics of the damaged parts, only damaged parts have been replaced. All parts were removed, photographed and kept together with parts from same cylinder in an oil bath.

The engine is the air cooled version - Hundreds of pics on my website (myketchlife.com)

My thinking behind my restoration project is that to really know my boat I should strip it down as much as I could. This would give me a lot more knowledge and understanding to carry out repairs at sea when there is only me. Mistakes in the workshop may cost time and money but at sea...

myketchlife.com
« Last Edit: February 07, 2023, 07:29:07 AM by Orion »

Orion

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Re: SR3 Rebuild
« Reply #5 on: February 05, 2023, 02:08:29 AM »
The timing marks are stamped into the outside face of the flywheel. They can`t be seen because of the bell housing that surrounds it, there should be a small viewing hole in the front of the bell housing. If I remember rightly there are marks for TDC and injector pump spill.

Bob

When I had the flywheel off I could not find any marks on it t all that might have represented the jagged timing mark - There is a note in my manual at the bottom of page 27 which states that the timing mark on LR2, SR2, & SR3 engines is on the side of the flywheel not on the back, which means that it won't show in the bell housing window. I didn't see this note until the shroud was back on.

Vern (Orion)

myketchlife.com
« Last Edit: February 07, 2023, 07:30:09 AM by Orion »

Orion

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Re: SR3 Rebuild
« Reply #6 on: February 05, 2023, 02:17:33 AM »
Welcome Orion and well done so far.
Please dont be offended byh anything I mention it is given as ideas not criticism.
You mentioned that you stripped and cleaned the injectors. This is normally a job that requires specialty equipment when assembling and setting the working pressues, so this thought should go on a list of why it may not start.
In order to bleed the fuel system it is best to do it in stages. May sound silly but confirm you have fuel running freely out of the tank. Easiest way is to loosen the fuel line at the filter body if this is the 1st stage of fuel flow. Next bleed the filter housing. There should be a bleed screw on top of the housing. Next I guess the fuel goes to the 1st of the fuel pumps, ensure fuel runs freely to each pump in order and make sure there are no bubbles. So far this may be all gravity fed, if not you are going to get tired of pumping by hand.
Next with the throttle open wide start turning the engine overand see the small amount of fuel rise from the top of the pump. It is really just a dribble at this stage. Do this for all 3 pumps. Then disconnect the fuel line from all the injectors and crank again until you see the same amount of fuel come out of the fuel line with no bubbles, again on all 3 lines. Connect the fuel lines and attempt a start up but be ready to shut it down just incase.
This is how I bleed a diesel fuel system only mine are single cylinders and I have been able with one engine to remove the injector and connect it to the fuel line, crank it over and physically see the atomised spray. If you see this spray do not try to touch it as it is strong enough to impregnate into your skin and this is painful and dangerous to your health.
As I have never had to do spill timing I am unable to help but ajaffa1 - Bob, can help.
I found my timing marks on the outside flat section of the flywheel which showed a - mark for TDC and a lightning bolt for spark/spill timing I think. You will need to find TDC on compression then really clean up the rim of the flyweel at the 12 o'clock position and use a good light to help you see it. Once I found mine I really cleaned them up with a wire brush and filled the marks up using a white oil base marker pen.
Good luck and keep us informed.

I'm not easily offended especially when I am lacking in the knowledge department! ;D ;D

According to the manual I need a spare injection pipe to do so. I did crank the engine over and got a very small dribble fro 2 of the injection pipes but I'll leave the priming until I get some replacement parts which include a new filter assembly - Thanks for the help so far 8)

Orion

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Re: SR3 Rebuild
« Reply #7 on: February 05, 2023, 02:19:29 AM »
Thanks for your help so far Bob - I have to go away for a week so I will get back into as soon as I get back and also by that time some spares I ordered should have arrived 8)

Vern

myketchlife.com
« Last Edit: February 07, 2023, 07:31:01 AM by Orion »

cobbadog

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Re: SR3 Rebuild
« Reply #8 on: February 05, 2023, 04:51:40 AM »
It certainly did break the camshaft.
I dont know why you would need another fuel line to test the injectors or see that the fuel is up to them. That small dribble is exactly what you should see so at least 2 of the racks/pumps are working.
Strange about the timing marks. I know my engine is a different model but the marks are on the outter rim of the flywheel and I transferred them to the outter edge so I can see them easily. I would keep looking for them and especially when #1 piston is at TDC on compression because that is when it should be seen, but just had a lapse of memory, yours is a 3 cylinder so may have 3 timing marks for spill timing.
Good luck with the progress and hope that the marks do turn up before you get to the stage you need them.
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ajaffa1

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Re: SR3 Rebuild
« Reply #9 on: February 05, 2023, 08:02:38 AM »
Hi Vern, wow that is definitely a broken camshaft. I am surprised it didn`t do more internal damage to the engine. On my ST2 the oil pump was driven off the nearest cam lobe to the governor mechanism, it is a simple piston pump accessed from a large threaded screw in the bottom of the engine. Check it out, if some piece of detritus got into it it could have seized causing the camshaft breakage, also check out the valves, guides and rocker mechanism associated with the breakage.
If you can`t find timing marks, it should be possible to time the engine by finding TDC on each cylinder and doing the math to work out how many degrees before TDC spill should happen. A protractor and a black marker pen should get you very close.

Bob

ajaffa1

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Re: SR3 Rebuild
« Reply #10 on: February 05, 2023, 10:35:17 AM »
Further to my earlier post, I have had a bit of time to think while walking my dog. Some camshafts have a deliberate waisting to ensure that they break in a safe area. I don`t remember seeing such a waisting when I rebuilt the ST2 but it doesn`t mean it wasn`t there. So any seizure of any of the rocker assemblies could cause a camshaft breakage. Please check all of the rocker assemblies. On the ST there are oil feed pipes to al of the rocker assemblies, I assume the same applies to SR engines, these have a very small bore but they also have a steel wire in them to further reduce oil flow to the rocker assemblies, check they are clear and without corrosion.
My major concern is that this was fitted in a boat, water, oil and bad servicing will inevitably end in disaster. If the problem was with the oil pump then something has been picked up and seized the oil pump. Check the condition of the screen on the pick up pipe. Mine was brass mesh, wouldn`t be surprised if the accountants changed that to steel mesh to save money on later model engines, water ingress would cause the mesh to corrode quickly in a marine application, allowing ingress of detritus and corroded mesh screen.
My best guess is that someone set the tappet clearance incorrectly and the pistons have kissed the valves. check the condition of the valves and look for dents in the top of the aluminium pistons.
One more possibility is if your engine has a fuel lift pump, this is also driven off the camshaft, if the gasket between the pump and the engine block is too thin it will cause undue stress on the camshaft.

Bob



Orion

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Re: SR3 Rebuild
« Reply #11 on: February 07, 2023, 07:42:15 AM »
Just thought I'd add some more pics to help you to become familiar with my SR3 - see link

Should be back working on it on Monday 13th

Cheers

Vern

https://www.myketchlife.com/blog/categories/engine-bay
« Last Edit: February 07, 2023, 07:57:14 AM by Orion »

Orion

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Re: SR3 Rebuild
« Reply #12 on: May 30, 2023, 09:07:10 AM »
Hi peoples, I have posted a video on youtube with the first start of my lister SR 3 in 2 years after a full strip down and recondition. We think it sounds alright but would like the "Brains Trust" to have a listen and give opinions, good or bad, on how it sounds. I am not a mechanic and did most of the rebuild myself and then got a proper marine mechanic to fix my mistakes! Anyway have a listen and I welcome your input. Thanks in advance  ;D

Orion

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Re: SR3 Rebuild
« Reply #13 on: May 30, 2023, 09:08:09 AM »
The link might help!!!  https://youtu.be/I34mBQlLiRw

cobbadog

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Re: SR3 Rebuild
« Reply #14 on: May 30, 2023, 01:20:10 PM »
G'Day Orion, you have done very well with the rebuild. I think it sounds just right so time to refit it back into the boat
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