12 replies to this topic

[ckendall]

Can anyone please shed some light on why i might have 3 bent pushrods in my 1275

the head , rockers and valves all look good ??????

if anyone can help before i strip the whole block down

[Bungle]

head gasket change recently ?

[mk1leg]

Yes it possible that the rocker's were not ajusted correctly and as there was no gap they just bent.............

[Guess-Works.com]

Are you running std rockers or high ratio rockers eg, 1.3, 1.5 or even 1.7's

[ckendall]

The lump in question is one i got recently so thats why im starting to strip it down
The cylinder head gasket looks new
to be honest i did'nt check the rocker gaps before i took the head off
and by the looks of the rockers there just the standard ones
Hope this helps a little ????

[Bungle]

i'm guessing someone replaced the gasket with out resetting the rocker gaps

[ckendall]

thanks mate just hope its nothing to bad further down the line

[Guess-Works.com]

you mean like a little piston/valve interference....

from what you've said so far even with the tappet clearance set a naff all I would not expect the pushrods to bend, certainly not with std rockers and probably std valve springs... so yeah I would be fearing the worst.

[ckendall]

Guessworks -- yes " a little piston/valve interference" all the valves look good with no marks on any of them ???? so hope not

[MRA]

this many bent pushrods.... leads me to think that it has also been fitted with a new timing chain and sprocket/s.... the sprockets can wear and allow the chain to slip...... and then a new (replacement) head fitted hence new gasket and now contact marks....

Pistons probably look fairly clean as if a de-coke was done recently ??

[cooperrodeo]

People give me a funny look when I relate this story, but I assure you it is true.

My Triumph Spitfire was laid up for twenty years in my garage, so that meant that the petrol left in the tank was pretty old but cheap. I rebuilt the engine and ran it a few times before leaving it a week or two. When I next came to start it, it was reluctant to turn over and then there was a sort of twang and it started, but running on only 3 cylinders.

It was running on only 3 cylinders because a pushrod had been bent by the starter and it had got out of the way of its rocker. The reason for all this was that the valve had seized in its guide (and others were pretty tight) owing to something in the old petrol solidifying around the stem in the guide. The valves were removed by persuasion, cleaned up and the old petrol dumped. Never had the problem again.

Edited by cooperrodeo, 07 February 2011 - 10:58 PM.

[bmcecosse]

I agree - push-rod on a 1275 can really only get bent by something like a seized valve or coil-bound valve springs.

[MRA]

If the valve springs were coil bound I would expect to see all 8 push rods bent......

A seized valve, would also be a contender, however 3 pushrods.... it wouldn't run too well on 2.5 - 3 cylinders and the chances of 3 valves seizing at the same time, would suggest tight guides and a very sudden reduction in oil, which would lead to other damage which if the case will show up on start