Author Topic: engine knock  (Read 322 times)

vegoil

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engine knock
« on: October 13, 2018, 11:51:31 PM »
help please,
I have a sharp loud knock in me Lister CS 8/1 SOM engine I have renewed the piston and pin + bush at top end, valves and seals also the big end, tested the new big end with plastic gauge 2.5 thu. I am at a loss to what the knock is. I had my hand in and felt the Governor is it rite that one of the weights should have play on it and the other one is tight up against the spring. there is a little back lash on the cogs.

has anyone had this problem?

broncodriver99

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Re: engine knock
« Reply #1 on: October 13, 2018, 11:59:13 PM »
Both of the weights have an ear/tab that run in the same collar on the cam. If one is loose and the other isn't sounds like something could be going on there.

broncodriver99

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Re: engine knock
« Reply #2 on: October 14, 2018, 12:03:47 AM »
Here is a link to a manual posted by another member. http://listerengine.com/smf/index.php?action=dlattach;topic=8320.0;attach=1178

Look on page 12 for a view of the cam setup.

vegoil

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Re: engine knock
« Reply #3 on: October 14, 2018, 12:30:58 AM »
thanks for the help, is it easy to remove the Governor assembly?
« Last Edit: October 14, 2018, 01:43:39 PM by vegoil »

glort

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Re: engine knock
« Reply #4 on: October 14, 2018, 09:51:13 AM »

Is it a definite metallic / ringing Knock?

Diesels that have a solid compression " Knock" is generally a good thing and means the engine is healthy. If you have had the engine apart, was the timing altered or set?

ajaffa1

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Re: engine knock
« Reply #5 on: October 14, 2018, 11:52:52 AM »
Hi Vegoil, removing the cam shaft assembly is not that difficult. The hardest part is pulling out the gib key and removing the flywheel (injector pump end). After that you will need to undo the injector pump fuel lines and disconnect the governor spring. Remove the 6" long governor linkage by removing the split pins and knocking out the linkage pins. Undo the two bolt holding down the injector pump and remove the pump.(put it in a clean plastic bag to prevent sh1t getting into the pump)

There is a governor linkage (the bottom one) which goes through the bell housing this has a large flange nut behind it, undo this nut, this will disengage the governor follower.

Undo the three retaining nuts shown in the photo and the front cover should pull off.

At the other end of the camshaft is a metal cover, remove it and knock out the taper pin and remove the bush shown in the photo.

The entire camshaft should now slide out from the other end. You will need to hold up the cam followers or they will catch, recommend you do this at TDC where there is no pressure from the valve springs/rocker assembly. You can now easily inspect the camshaft and governor assembly it should look like the photo.

Let us know how you go and please ask any questions,

Bob

vegoil

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Re: engine knock
« Reply #6 on: October 14, 2018, 12:45:27 PM »
thanks I will let you know.

sirpedrosa

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Re: engine knock
« Reply #7 on: October 14, 2018, 09:37:15 PM »
Hi Bob

Is this your "baby"?

As far I can see you had been done a herculean job, in all that pited iron. Congratulations, apply the same effort to your health and I'm sure you'll make it.

And for the forum records, there is nothing like  an explanation with images. Super!

Keep your will!

Cheers
Pedrosa

PS: Vegoil, you have your ear in the right place.
Bernard 18A - 1968

vegoil

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Re: engine knock
« Reply #8 on: October 14, 2018, 11:15:49 PM »
Hi,
I have set the injection timing it was to far advanced 25deg set it back to 20deg sounds a lot better, there is still sum knocking but not near as bad, it turns out that the zigzag mark on the flywheel was at  25deg advanced when I came to set it with a digital incline meter. an engine mechanic was along today he said she is running sweet and the knock that is there is nothing to worry about. running under load there is no black smoke. when I hold my hand at the end of the exhaust, all that is there is water vapour but the exhaust goes threw a concrete box with baffles.

I will still keep one ear on it!

what is the easy way to put photos on here from my computer?

John

glort

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Re: engine knock
« Reply #9 on: October 14, 2018, 11:52:28 PM »
I have set the injection timing it was to far advanced 25deg set it back to 20deg sounds a lot better, there is still sum knocking but not near as bad, it turns out that the zigzag mark on the flywheel was at  25deg advanced when I came to set it with a digital incline meter. an engine mechanic was along today he said she is running sweet and the knock that is there is nothing to worry about.

John

Haha, Called it!   :laugh:

Been there, done that.
Have a China Diesel water pump that was the same. Sounded like it was going to self destruct.  Worse on Diesel than veg which made me suspect the timing. Shimmed it out and the thing runs sweet as a nut.  Had other engines Similar. If it's not metallic noise,  it's timing. You want max Cylinder pressure acting on the piston on the down stroke, not max pressure occouring before the piston has completed it's travel on the upstroke. That's what makes the bad Diesel Knock.

A good diesel clack is when the pressure is peaking at the right time effecting max force on the piston in the right direction of travel and is a sign of an engine with good compression firing properly to me.  People in Veg oil circles used to be happy when an engine got quiet not realising it was probably not burning the fuel properly and leaving lots of residue in the Cylinder.  If the timing had gone a bit slow and you put a slow burning fuel in it as well..... Not good long term.

Can't help with the pic upload. I think doing it direct is a bit tricky.  You have to have somewhere on the web hosting the pics. There are various sites and services that do this but never used those either. Had my own site as long as I can remember and find it much easier to host my own pics. ( and no more exy than a lot of these paid sites although some are free) and upload there.

ajaffa1

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Re: engine knock
« Reply #10 on: October 15, 2018, 12:15:38 AM »
Hi Vegoil, glad you got it sorted without having to dismantle everything. Nice call Glort!  ;D

When you post on the forum, at the bottom of your screen is a box labeled "attachments and other options". If you click on this it will give you options to attach files from your computer. There is a maximum size of upload and I believe you are restricted to four attachments.

Bob

mikenash

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Re: engine knock
« Reply #11 on: October 15, 2018, 12:28:07 AM »
Hi,
I have set the injection timing it was to far advanced 25deg set it back to 20deg sounds a lot better, there is still sum knocking but not near as bad, it turns out that the zigzag mark on the flywheel was at  25deg advanced when I came to set it with a digital incline meter. an engine mechanic was along today he said she is running sweet and the knock that is there is nothing to worry about. running under load there is no black smoke. when I hold my hand at the end of the exhaust, all that is there is water vapour but the exhaust goes threw a concrete box with baffles.

I will still keep one ear on it!

what is the easy way to put photos on here from my computer?


John


Hey Vegoil have you seen this thread?  On the WOK?

http://listerengine.com/smf/index.php?topic=7374.0

Valve clearances/timing done by degrees not by "clearance".  I think the engine may run "quieter" if timed this way - others more knowledgeable will probably chip in

And photos?  All I have ever done is re-size them on my computer so they are at 100% on the screen - or slightly smaller, save them a JPEGs and then use that attachments tool below

Cheers

dieselspanner

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Re: engine knock
« Reply #12 on: October 15, 2018, 08:40:00 AM »
Mi Mike / John.

I did my CS by religiously following Butch's tutorial when all else was giving less than desired results, worked like it says on the tin!

It helped me work out that the camshaft was a tooth out even though I'd installed it 3 times exactly to the marks. In the end I put timing marks on the camshaft retaining collar as well.

Another good tip from Butch is to make a pointer and fix it somewhere around the injector pump, close to the rim of the flywheel, then mark that at TDC. derived from the engine, not any existing marks on the flywheel.

Having done that wrap a piece of thin string several time around the flywheel and cut the ends dead level. Unwind it and measure it. divide the length by the number of turns, then by 360 (the more turns, the greater the accuracy) Mine was 5.13mm, from memory.

You then have the distance on the rim of the flywheel for each degree and with a suitable marker mark off each each 'event'  -  Inlet valve opening and closing, ditto exhaust and IP timing by multiplying the degrees before or after TDC by YOUR result, not mine, and you'll have the best timing wheel ever. Bigger IS better in this case.

Then you'll know exactly what's happening when by watching the cam followers and listing for the 'creak' of the injection pump

Once I was satisfied I marked the flywheel with a chisel and small letter punches.

Cheers
Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.