Leyland engine with flat topped rocker cover

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roy.thomas
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Leyland engine with flat topped rocker cover

Post #1 by roy.thomas » Tue Apr 24, 2018 4:43 pm

Hi,
I have been having problems with the engine in my JCB 3C3. It is a Leyland, and in the past I have had to renew the cylinder head gasket every year, but in 2014 someone told me to use wellseal, and till yesterday all was well. Unfortunately it started playing up again yesterday. It seems to be marking the head gasket between pistons 1 and 2 and loosing compression and consequently water. The cylinder bores are fitted with wet liners. Either one or both liners have a seal at the bottom and either one or both may have moved slightly downwards.
Has anyone come across this? Is it possible to get a head gasket that can compensate for that?
I am hoping to get away with a quick fix, rather than take the engine out, as it is rather a big job to remove the liners. It is a Leyland 4 cylinder engine with a flat topped rocker cover.
:dizzy:


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Re: Leyland engine with flat topped rocker cover

Post #2 by justamin » Tue Apr 24, 2018 10:11 pm

You can do the liners with the engine still fitted


Jeremy Rowland
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Re: Leyland engine with flat topped rocker cover

Post #3 by Jeremy Rowland » Wed Apr 25, 2018 7:23 am

While I have no working knowledge on Leyland engines I can tell you that many wet liner engines can have shims fitted underneath the liner to raise them up you need to use a dial gauge to measure the liner protrusion so you know what size shim you will need to fit underneath it this should permanently cure the issue.

Jeremy


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Re: Leyland engine with flat topped rocker cover

Post #4 by essexpete » Wed Apr 25, 2018 9:38 am

If you do as Jeremy has said and the liners measure OK would it worth having the head skimmed? Also have you had any over heating problems? I ask because we had a problem with a powertrain and the radiator was blocked externally in the cores although I had thought I had cleaned it sufficiently. hard to see behind the oil cooler.


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Re: Leyland engine with flat topped rocker cover

Post #5 by roy.thomas » Wed Apr 25, 2018 2:24 pm

Thanks so much for your responses. I will have a go getting shims fitted underneath and get the head skimmed. I haven't had any problems with over heating - only if the engine looses water because of the head. We fitted a new rad about 2 years ago.

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Re: Leyland engine with flat topped rocker cover

Post #6 by FOWLER MAN » Wed Apr 25, 2018 3:09 pm

Hi
I have worked on many of these engines over the years and yours is quite a common problem.
Jeremy is right when he mentions shims, but you don't need a dial gauge to set the standing height of the liners.
I have often managed quite well with a straight-edge and feeler gauge.
The height above the face of the block should be between 3 & 6 thou.(.003 & .006 in.)
This is measured from top of the shoulder on the top of the liner not the top of the fire ring. If I remember rightly the shims came in 3 and 5 thou.
We used to put the liner in without the seals to check this, making sure everything was clean and pressing the liner firmly against its seat. Then refitting it with the seals and the necessary shims.
As has already been mentioned this can all be done with the engine in place.
Fred


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Re: Leyland engine with flat topped rocker cover

Post #7 by roy.thomas » Sun Apr 29, 2018 3:38 pm

Help needed once again please for the Leyland Terrier 4/98 engine.

When I removed the cylinder head, I turned the engine in an anticlockwise direction, because it was easier to turn over that way with a bar as the engine is in a JCB.

We replaced the head and it seems as if a valve is touching, when we turn the engine clockwise for nearly a full turn. No damage done as yet.

Does anyone know where the timing marks are for this engine?
Could be on the front around the pulley area or in the flywheel area, but I cannot find any.

Also does anyone know the valve timing for this engine?

We made sure when fitting the head that the pistons were all in the same position, about halfway up the bores.

I was thinking that if I take the push rods out and then are able to put the cam shaft in the right position, we would do no harm, does anyone agree?

:?:


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Re: Leyland engine with flat topped rocker cover

Post #8 by Jeremy Rowland » Sun Apr 29, 2018 4:39 pm

Roy your valve timing cannot be out unless you have removed the cam or crank?

Jeremy


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Re: Leyland engine with flat topped rocker cover

Post #9 by agrimax » Sun Apr 29, 2018 6:55 pm

As Jeremy has said,unless you've had the crank or cam shaft out,the timing cannot be wrong. Just for reference,there are timing dots on the gears behind the timing cover but if you've only removed the head and pistons,nothing else will have changed.Turning the engine anticlockwise won't matter,nor does the position of the pistons before fitting the head.What makes you say a valve is touching? Could you have screwed the rocker adjuster screw down too much,preventing the valve from closing,or has a piece of dirt fell into the tappet socket before installing the push rod? Only other thing is if the head was skimmed too much,a thicker head gasket would be needed. Don't know if an oversize gasket is available for these but would expect all the valves to be touching the pistons now rather than just one................


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Re: Leyland engine with flat topped rocker cover

Post #10 by roy.thomas » Sun Apr 29, 2018 8:17 pm

Thanks for the responses. I will check tomorrow to see if the rocker adjuster screw is down too much, or indeed a piece of dirt has fallen into the tappet socket. It is very cold out there today, so am leaving it till tomorrow.


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