Push Rods

After my breakdown earlier in the year I put the van in the garage and hardly touched it. Anyway decided a new year and all that so I would set the valve clearances and have noticed one of the push rods is touching the push rod tube.

Never noticed this before so don’t know if it is new. Any ideas what has caused it, should I worry and what is the fix?

 

Not sure. It moves okay, thinking I may need to take it out and check. Was hoping for a very quick job of checking valve clearances and starting the engine today so might have to do that at the weekend.

 

Okay not bent but badly scored so it has been rubbing. The one on the left. The next one along has scoring but not as bad. These are both number 2.

 

What was the cause of the breakdown earlier in the year and what was done to stop it breaking down?

Are you sure the pushrods are located in the followers properly and the rockers are in the right place?

 

Just put it back on, seems to be seated correctly in the rocker but still touching the push rod tube and I can’t work out why.

 

But are they seated in the followers properly? Are all the adjusters sticking out the same amount?

 

Honestly I don’t know.

Feels as though they are. I have it turned to adjust number 2 and both seem to be in line.

The one which is badly scored and touching looks like an Empi adjustable tube and seems to have less clearance than the others which appear to be the non adjustable type.

 

I don’t know if the inlet rockers are different to the exhaust on a type 1 but if they are they must be in the right place. If those two adjusting screws have more thread exposed compared to the other cylinders it’s a clue that the rod isn’t located in the follower properly. I doubt if the problem is the tubes.

I’ll ask again, what was done following the breakdown, specifically was any work done to the engine?

 

Apart from my roadside tinkering on breakdown (it was misfiring and struggling to run) it’s been in the garage, only changed the fuel filter and checked a few fuel lines last month. Not started it up again yet but it did run off the tow truck okay. I’m thinking it was the float valve on the carb which is the issue with that so I have bought another carb to swap over, the next job.

When I was having breakdown issues I checked the valves and didn’t tighten it up correctly resulting in that one coming loose on a run. Could that have caused it to be out of line? If yes where is it out of line as the rod looks straight?

 

If the adjuster was very loose the rod could have come out of the cup in the cam follower. And that really is the only reason for the rod to be out of line. But if the rod isn’t in the cup the adjuster screw would have more exposed thread compared to the other cylinders.

I think the inlet and exhaust rockers are the same on a Type 1 but spacers are available to adjust the position if necessary. Are the rockers centred on the valve stems? https://www.machine7.com/section.php?xSec=2510&jssCart=aea660851288ab7838108ba6712da218

 

They seem to be centred but again I’m guessing. Thanks for the link to spacers.

I’ve put it back together and did start it. Sounds a bit rough but the engine runs (didn’t run it for long just wanted to check it would start).

I’m going to have a brew, take Xmas decs down and do some reading, really bemused by this and wondering if it has always been like this I just haven’t noticed.

 

Its probably a bodge up by somebody who did not want to take the head off, so they used an EMPI telescopic tube to replace a damaged pushrod tube. I carry a CB telescopic pushrod tube just for that purpose as a spare.

Best bet is to take the head off, get a stock pushrod tube and re-stretch the other three to the specification in Bentley - or at least to match the length of the new one. And buy a set of new pushrod tube seals and use them (or the better quality Elring gasket set includes some that have worked well for me in the past)

The simple test for your pushrod is to roll it on a flat surface -if it rolls smoothly its straight, otherwise it is curved.

 

Cheers, will try the roll test.

I actually have a set of Scat big mouth tubes on the shelf and was wondering if I should replace the Empi one with that to see if there is clearance.

Will think about the head change although I’m a bit reluctant to go down that route yet (until at the least the weather is a bit warmer).

 

That exhaust valve tube doesn't allow much room for tolerances and the other one is clearly crumpled too. I think it's just the tubes and unlucky combo of parts. The rocker shaft looks too new to be original so that might also be a bit off tolerance contributing to your perfect storm. The shaft will fit if you rebuild it up with the left side on the right which might centre the pushrods better and is a quick easy job.

 

Just remember that the blocks that secure the rocker arm to the head have two different sized holes : 8mm by the nut and 10mm by the head, the hole nearer the head is bigger as there may be shoulder in the stud. Forget this , get out the torque wrench and you may be met with a challenge. As below, this block was installed with the small hole near the head.

Just as well that by this stage I had a spare set of rocker arm assemblies, as trying to lift the rocker arm away from the head at that point without levering on the soft metal of the head resulted in snapping the block.

I believe they are also meant to be installed with the slot to the top of the engine.

 

It's probably as suggested above, just an unfortunate combination of aftermarket parts. However I just dug out a pic I took of my rocker gear last year and comparing to yours, something just doesn't quite look right with your rockers - but maybe it's just the angle the pic was taken from?

Just to add, I'm running 'elephant feet' adjusters with shims under the shaft pedestals to compensate.

 

That's one of your most confusing posts of all time. You'd have to a blind gimp to install the block upside down the way you describe, it would look so wrong + in you photo it looks the right way up to me. It does look like a cheapo stud though?