offroadmad
Active Member
lol - the engine is currently in bits i am awaiting a p/rod & rocker gasket, will keep ya all posted.
I to am trying to understand the bent push rod as the only damage, the best I can think of is the valve stem is slightly bent also, and the piston is punching it shut, that would impart force down the rod but the follower would be off the lobe so there would be little or no resistance, so I still cant see the rod damage.
Dev
Dev
offroadmad
Active Member
The valves all appear to be strait as they all close fully ! if there was water in the cylinder the push rod would bend trying to open the valve is what ive come up with - however it all swings on what happens when i fit new rod - could be cam follower yet
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jamesmartin
Well-Known Member
you can check follower using torch looking down from top follower is two parts roller that wont break on cam and brass slide push rod sits on rod can push through ,but can be seen from top with rods out
I wish I had your faith in this situation.
You said it is an exhaust valve pushrod that is bent. The exhaust valve starts to open as the piston gets near the bottom of the bore, then stays open as the piston goes all the way back up, finally closing some degrees after the piston has reached top dead centre, by which time the inlet valve is also opening. There is a considerable "overlap" when BOTH valves are open at the same time as the engine cycle changes from 'exhaust' to 'induction' strokes.
But, I am stuck for an explanation for an exhaust valve being under such strain that it bends a pushrod, EXCEPT if (a) the piston hits the valve when the belt breaks or slips, or (b) something fairly solid is sucked into the engine and ends up between the piston crown and the exhaust valve as the piston is rising in the bore towards the valve as it is closing. They don't miss each other by much in LandRovers, and a quite small item could cause impact. If that had happened, I would expect to see marks on the piston crown.
Have you checked that the valves are free to move by pushing the valve stem tips down? Some of them will move very little because the pistons may be up and down, but in a 4-cylinder engine if it stopped from running, that should not be the case. You may have turned it to Top Dead Centre when checking, in which case pistons 1 and 4 will be UP, and 2 & 3 will be down.
As James says, you should be able to see a damaged tappet by looking down. I think this drawing shows what your tappets look like. James will probably confirm that the head needs to come off the change tappets.
Attachments
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offroadmad
Active Member
charles my faith has dwindled tbh - almost had enough - will check valves push & return & await arrival of the pushrod, its probably not going to solve it like you say but im not removing the head unless i really have to - starting to wonder if the little bit of fun i get out of it when off roading is worth all the hassle
I do appeciate you all trying to help - just dragging on now - i just want to know whats wrong - just need some positive injection lol
I do appeciate you all trying to help - just dragging on now - i just want to know whats wrong - just need some positive injection lol
jamesmartin
Well-Known Member
cheer upmr offroadmad you dont know till you try new rod ,if your confident all other rods are straight and follower sockets look good round inverted dome and not squashed looking dome ,we could speculate till the cows come home ,try it and go from there, redhands had success so you may ,one proved step at a time ,just ensure tappets are set correctly (number nine method) 8 thou ,and turn engine over by hand a few times to ensure no contact with pistons before starting
offroadmad
Active Member
cheers james, will check tappet slides with a torch tmrw & check valves go in & out nicely
must keep faith lol
My names stu by the way - easier for you to type lol
must keep faith lol
My names stu by the way - easier for you to type lol
OffRoadMad,
When you opened up the engine was the top end of the pushrod (the socket) engaged on the ball end of the rocker adjuster screw?
A collapsed cam follower would be expected to create excess "valve clearance" and in that circumstance it is just possible (I have seen it once in over 50 years) for the pushrod to drop too far, slip sideways off the ball end of the rocker, and as the cam comes round to lift the follower, the EDGE of the cup on top of the pushrod catches on the bottom of the rocker adjuster ball end, and pushes it up. Of course, it can't now go that far because the valve is trying to go DOWN almost twice as far as the pushrod is coming up, as the two sides of the rocker are different lengths of lever, and the ball end of the rocker is sitting on the EDGE of the cup, not deep down in the socket.
So the valve goes too far down, hits the piston and mangles the pushrod.
This still depends on a damaged follower, UNLESS by a glorious fluke the water somehow caused the exhaust valve to stick OPEN which could allow the pushrod to drop clear of the rocker ball-end, and Bob's Your Uncle!
How lucky do you feel Mr OffRoadMad ?
Prayer often helps, and God did invent LandRovers!
When you opened up the engine was the top end of the pushrod (the socket) engaged on the ball end of the rocker adjuster screw?
A collapsed cam follower would be expected to create excess "valve clearance" and in that circumstance it is just possible (I have seen it once in over 50 years) for the pushrod to drop too far, slip sideways off the ball end of the rocker, and as the cam comes round to lift the follower, the EDGE of the cup on top of the pushrod catches on the bottom of the rocker adjuster ball end, and pushes it up. Of course, it can't now go that far because the valve is trying to go DOWN almost twice as far as the pushrod is coming up, as the two sides of the rocker are different lengths of lever, and the ball end of the rocker is sitting on the EDGE of the cup, not deep down in the socket.
So the valve goes too far down, hits the piston and mangles the pushrod.
This still depends on a damaged follower, UNLESS by a glorious fluke the water somehow caused the exhaust valve to stick OPEN which could allow the pushrod to drop clear of the rocker ball-end, and Bob's Your Uncle!
How lucky do you feel Mr OffRoadMad ?
Prayer often helps, and God did invent LandRovers!
offroadmad
Active Member
lol cheers mr n
offroadmad
Active Member
charles - the pushrod & ball seemed to be engaged properly before removing rockers !
OK ..... your luck may be running well.
So as not to lecture about engines (James doesn't approve of that), PM me if you like and I will let you know by email what I would do next if it was mine.
It is still posible there's a problem, but there is hope!
These are VERY tough engines.
offroadmad
Active Member
Tbh charles i know exactly how the engine works now which is a great help & im more than capable of doing anything really so i should be fine - should know tmrw when my torch is charged ! Cheers for the offer of help & all the advice provided so far - I feel i owe a few ppl a beer already & havnt been using l/z long 
Maybe you can tell us how a bad big end or small end bearing could have caused OffRoadMad to get a mangled pushrod!
Big End noise and Little End noise are completely different sounds.
Once you have heard some, you will know.
If you put a nice bright chalk mark on the crankshaft pulley where you can see it, you can fire up the engine and LOOK and LISTEN.
What you want to find out is this :
Does it knock EVERY rotation of the crankshaft, or every SECOND rotation?
Once you know that you can eliminate a whole lot of possibilities.
.
offroadmad
Active Member
right i have looked down the p/rod holes & all tappet slides look identical & i cant see anything broken in there - ordering push rod tmoz - fingers crossed !
WOW!!!!
Now what I suggest you do is to MAKE SURE the camshaft belt has not slipped.
Remember, SOMETHING HAPPENED that caused that pushrod to get mangled, and at least 99 times out of 100 that happens because the piston and valve collided.
I know this might sound like a pain in the bum, but, I strongly suggest you take the plunge and get enough bits off the front of the engine to be able to see the timing belt and the check if the timing marks are still spot-on.
In fact, if you go that far, you should fit a new belt, and I think you should take advice about the belt tensioner too.
Lots of people here will have very specific experience of the engine type (300tdi, right?) and those Goddam rubber bands that run the pump and camshaft, and you would do well to hear what they have to say.
Remember, we cannot escape the fact that SOMETHING HAPPENED at about the time you took her swimming, and you really need to find out what it was, and if the problem it caused is still there. It is always worth keeping in mind that "wading water" invariably includes grit and small gravel, and even a tiny pebble between the belt and the pulley could lift the belt enough to allow it jump a tooth or two on the crankshaft sprocket, without snapping the belt.
Take EXTREME care turning the engine after you set the valve clearances.
You don't want to buckle another rod or two at this stage.
Do NOT whirl it over on the starter until you are SURE there is no piston~valve contact taking place AND the timing is still correct.
Good Luck! It's looking hopeful.
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offroadmad
Active Member
its a 200 tdi - cambelt was done by myself less than 1000 miles ago - will not be checking timing ( i know i should ) but its a right bugger to get at - there must be a way of checking it hasent slipped without taking it all appart again. - surely if the timing had slipped i would have more than one bent p/rod as the chances of only one valve meeting the piston if the belt slips is almost impossible - agreed ???? or am i completely wrong ?
The valves are all strait as if they were bent they would not close correctly - so i would be amazed if its slipped a belt.
Dont get me wrong im not argueing - u guys blatently know more than me but im not going through all that again to find out it has not slipped.
The valves are all strait as if they were bent they would not close correctly - so i would be amazed if its slipped a belt.
Dont get me wrong im not argueing - u guys blatently know more than me but im not going through all that again to find out it has not slipped.
offroadmad
Active Member
im preying that i have redhands luck !
