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Advice on a non-rotating pushrod

BlackLightning998

Well Known and Active Website User
VOC Member
Afternoon all.

On adjusting the valve clearances I noticed that the front cylinder inlet pushrod would not rotate, even with the adjuster freed right off. I adjusted the play properly and took it for a run - everything perfect. Inspection cap off - still won't rotate but adjustment fine. I took the adjuster out and lifted the rod, I think I can feel it bringing the ET29 (lower cap) up with it until it stops/won't come any further. Gentle upward pressure with a rag and some pliers won't bring the pushrod out any further.

I suspect that when work hardening the bottom end of the rod has gone slightly oversize and locked itself into the ET29. I guess this is bad news and will need to be resolved?

I've ordered up a new pushrod but was looking for advice from Forum members on two questions:

1 - Anyone come across this before and am I likley to have identified the problem correctly?

2 - How do I go about changing the pushrod safely - I read in an old MPH of a guy who dropped one past ET29 down into the engine and got it stuck fast - having then to strip the head off - no thanks!

All advice gratefully received.

Cheers all

Stuart
 

Phil Mahood

VOC Hon. Computer Officer
VOC Member
Stuart,
I've seen this a couple of times. In both instances, the pushrod was siezed in the cup of the cam follower. These were engines that were rebuilt over 10 years ago and seemed to be using new push rods and/or followers. Attention must be paid to the shape and finish of the cup. I've seen followers that were deficient in both respects.

In both cases, I was able to rectify the problem by lapping in the pushrod. Using fine valve grinding paste, and the rod held in a hand drill, I achieved a polished surface in the cup, and clearance all around. Problem solved. Obviously you need to remove the timing cover, staedy plate, and cam to extract the follower. Ergo refitting is easy.

It is always best to remove the timing cover when refitting push rods. Then you can poke about and be sure they've landed in the cups. Failing that, remove all the valve caps and shine a light down another pushrod tube. You can then see the exact location of the target cup. This will improve your odds and give you a chance of dropping the pushrod home. Again, use the pen light to verify as best as possible. Good luck!
 

BlackLightning998

Well Known and Active Website User
VOC Member
Thanks Phil

Hi Phil,

Thanks for the reply, sounds just a little complicated for a beginner like me though, mmmm - need to think about that one. The engine was re-built a year ago by Terry Prince in Australia - I have all the paperwork that came with the bike and it would appear (on the face of it) that it may well have new followers but the original pushrods - seems a strange money saving decision. When I bought the bike from the chap who had it re-built, with it came two large metal ammo boxes with all the parts that have ben changed and sure enough when I look through them this afternoon the rockers and cam followers are there, as are the valves and associated parts, even the pushrod tubes were replaced and originals are in the box - but no pushrods? Odd.

I could just about stretch my skill set to seeing if I can get hold of the pushrod with some mole grips and gently tapping upwards to see if I can free it up from the ET29 - then replacing it with a new pushrod (hoping that I get one that 'fits' from stock. What do you think - should I give it a go or should I find myself a Vincent engineer to have the job done properly?

Cheers

Stuart
 

barrys

Active Website User
Non-VOC Member
sticking pushrod

hi stuart, if in doubt do nowt! old saying but may save you loads of grief! and money, find a vin man give Derek Sayer a ring 0208 304 1527 he will put you right, works on them for living rebuilt my B twin engine a few years ago no problems at all , used to do home visits with tools! regards barry.
 

Phil Mahood

VOC Hon. Computer Officer
VOC Member
Stuart,
I have to concur, it would be best if you had someone experienced, even if just to show you the ropes. Failing that, taking the bike to a professional will ensure it gets sorted. This is probably not to big a job, but it is hard to say until someone digs in. There may be other things at play that are contributing to the problem.

Your idea of pulling up the pushrod is definitely something one would do at the side of the road, in an emergency. It would probably get you home. I would not trust the solution until I had all the bits in hand for an up-close inspection.

Let us know how you make out. Good luck.

Phil
 

BlackLightning998

Well Known and Active Website User
VOC Member
Thanks Phil and Barry

Thanks Phil and Barry,

Although the bike is running fine, I know there is something wrong as the pushrod is meant to rotate and it is not - it will wear in one plane so that's not good. Although not an experienced engineer, I do have an inquisitive mind and so it needs to get sorted - it wasn't designed this way.

There are a couple of people that have helped me before who do have the necessary skills and experience to help out and both offer their skills to Vincent Owners in retirement to keep cash flowing in, so I will make tracks to one of them - failing that being a possibility then I will call Derek who comes so highly recommended from a number of sources, including currently putting Graham Smith's Shadow engine together.

I'll try and get it organised this week as the weather is set to improve and the riding season is fast approaching.

I'm very grateful for your interest and support - I'll certainly keep the Forum posted on how I get on.

Such a damn shame when the bike looks gorgeous and runs faultlessly, and I got the tank back on again without trapping any cables or changing the carb. set up. That's life I guess.

Cheers.

Stuart
 

BlackLightning998

Well Known and Active Website User
VOC Member
Thanks Trevor

Hi Trevor,

Thanks for your posting.

In your experience is it a matter of pulling the rod and reducing OD by spinning it in the lathe and using some wet and dry - or is it a bigger job whereby the timing case cover needs to come off and the follower be removed to ensure that the ball end of the rod and the cup of the follower are lapped to work with each other?

What would you recommend doing?

Stuart
 

Tom Gaynor

Well Known and Active Website User
VOC Member
Pushrods

It's possible the reason the originals weren't replaced is that they were work-hardening stainless steel, and the only ones now available are flame-hardened silver steel. Which is best is arguable, but I like the stainless ones: initially they are soft, but as they wear to shape they harden. Maybe your engine builder thought that too. I was obliged to replace one of mine after "an accident" in which it was bent, so I decided to replace all four - which is the only reason I know this.
Cheer up: if they are silver steel, at least they can be fished with a magnet if one drops in.........
I'd take the timing cover off so I could see what was going on, despite the temptation to use the Mole wrench idea as a quick fix. I suspect you're not the first person to have this problem: 80% of my "new looking but old" pushrods have curious vertical scars on them, just where a Mole wrench would clamp. Probably just coincidence.......
 

clevtrev

Well Known and Active Website User
VOC Member
Hi Trevor,

Thanks for your posting.

In your experience is it a matter of pulling the rod and reducing OD by spinning it in the lathe and using some wet and dry - or is it a bigger job whereby the timing case cover needs to come off and the follower be removed to ensure that the ball end of the rod and the cup of the follower are lapped to work with each other?

What would you recommend doing?

Stuart
If you remove and reshape, a few more miles down the road you will be back to square one. Waste of time lapping the cup, the shape will be determined by the rivetting action and the hardness of the two components. Is the top cup free ? if so leave alone and ride on.
 

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