Bent push rod

[L19MUD]

Not a Land Rover engine but it is the lorry I use to get land rovers to comps and I'm sure someone on here will have a lot more experience than me!

Vehicle is an Iveco cargo tector 53 plate although I suspect this would be the same for any diesel push rod type engine

It's a 4 cylinder turbo with 4 valves a cylinder

I had the head off at the weekend to sort a suspected head gasket problem (head sent away for pressure testing and skimming) as I was getting exhaust gas in the coolant.

When cleaning up all the parts I removed so that they were ready for fitting I spotted that just one of the 8 push rods was bent. This has caused it to rub slightly on the wall of the block or head but it isn't actually very different in length to the other rods.

What would have caused this? Sticky valve?

What's my best course of action? I really don't want to have the cam out but think I should probably change both the valves that are operated by that rod?

No visible damage to the rocker, and you would have never known from the sound or performance of the engine that the rod was damaged before I stripped it.

Advice please!

[Landrovernuts]

I am sure this is a Cummins engine (ISB 3.9/Pacar) and I have seen a few bent valves on these engines and the bigger ISC engines. While you have the head off check the valves, if all OK put it back together with a new pushrod (that is what I would do anyway!) Cummins will rip you off for a new engine. When I worked for them I saw them do it for a leaky injector on a bus engine, more fool the bus company!

[steve200TDi]

I don't know about your engine, but generally I would do the following:

- As your having the cylinder head skimmed that therefore means it has to be stripped. You could vacuum test the valves 'as is' to see if any are leaking before the head is stripped, skimmed and cleaned, then lap all the valves in again for the head rebuild.

- You say you don't want to remove the cam, but with the head removed you should be able to inspect the follower that the push rod sits in for damage and replace the push rod if neccessary.

Steve

[Landrovernuts]

From what I remember you cannot get the followers out that easy, think the cam has to come out and then the followers drop down. Best way to see the cam is from the bottom with the sump off!

Toby

[L19MUD]

Thank you both for your comments. It is a Tector engine which i believe is the next one on from the Cummins engine (I dont know if the Tector was developed from the cummins?)

The head is away for testing and skimming now - I got away without touching the valves as they are recessed into the head and hence wont get in the way.

Landrovernuts is unfortunately right - the cam is way down the block and you really cant see anything from the top (the push rods must be 9 inches long to give you an idea. On the basis that the ball ends of the push rods all look fine with no damage and are all identical then I will have to trust that there are no problems down there - fingers crossed.

As I haven't had to take the valves out for the skimming would you remove any of the other valves other than the two I need to check due to the bent push rod? On the basis that I had no other problems other than exhaust gas in the coolant then I am presuming all the other valves are in good condition and sealing properly.

The engine has gone into the red a couple of times (but then stopped quickly after) could this excess heat have resulted in a sticking valve and bend the push rod? Then the valve would free itself off when it cooled - surely if I had a sticking valve it would have been noticable all the time?

Time to learn how to take valves out and lap them I think!

Thanks

Sam

[fozsug]

I think they are Hydraulic followers, just a thought but the follower's two halves are unscrewing ?, i know this means droping the cam out.

[steve200TDi]

Time to learn how to take valves out and lap them I think!

Thanks

Sam

Yep, I would as you want to wash out all of the swarf created from the head skim.

Removing valves are quite easy after you've done the first one. I bag up each valve, spring, collet etc in one bag so you know where they cam from. Once you put the spring compressor on you could find it difficult lock it so that you can remove the collets (normally with a magnet). A good tip would be to find a deep socket that fits over the collets and sits on the spring retainer, then you can give it a sharp tap with a mallet to shock and release the collets so that it will be easier when you use the valve spring compressor.

When you refit the collets stick the collet to the end on a screwdriver with some grease for easier application!

Steve

[cackshifter]

^{If you can get it under, a pillar drill makes a good valve spring compressor - you need a piece of pipe with say a bolt welded on one end and the sides cut away a little, mounted in the chuck by the bolt; it is much more controllable than a traditional compressor.}

[Landrovernuts]

From what I remember we used to hold the followers up in pairs with rubber bands to pull out the cam and then drop them down, if you did want to take the cam out! I would check the valves (you will need to after skimming to get the swarf out as already mentioned) and then go from there. I cannot remember, but is it not easy enough to drop the sump to check the cam?

I have to say this is not the best engine (neither is the ISB5.9) that Cummins made, the old 6B and 4B engines were much better and reliable, well maintained ones used to clock up many thousands of miles and could make 350 hp.

Toby

[moose]

If the engine has Hydraulic followers or lifters don't these need oil to work properly.

I had once had a heep Cherokee it was a bit of a company works car (ie people with no mechanical sympathy would some times use it), with the diesel VM engine it had quite high mileage and this used to bend push rods for time to time.

What i think was happening was as it use to sit standing some times for weeks at a time the oil would drain from the lifters and so some time they might have stuck bending the push rod. So to stop this we never used any revs until the engine had idled and started to warm a bit. It never bent a push rod again.

just a thought..

[L19MUD]

I'm waiting for the head to come back from being tested and skimmed but plan to take all the valves out at the weekend and give it a through clean.

One of my friends works at an agricultural dealers and is used to doing valves so he is bringing all the tools (and experience!) to do them so that should be sorted.

Interesting point re hydrualic followers - I know that the lorry was used fairly sporadically for 6 months before I bought it, and it certainly does not get used for up to a month at a time since I have had it. I do normally let it idle and warm up before taking it out of the yard - I will make sure I always do this going forwards - I certainly dont thrash it as repairs come out of my own hard earned funds!

On that basis I think I will refit the head after doing all the valves and changing the one bent rod then check the rods again after a few uses. Its pretty easy to take the rocker cover off to change a rod if I had to.

On the plus side - being a lorry everything is easy to get to with the cab tilted forward. My lorry has only done 400k so I should hope there are a good few years left in it yet (I only did 5k last year!)

Thanks for all your help!