Pushrod Problems

[u28909z]

I went on a 100 mile ride around the peak district yesterday. The A10 went reasonably well until 5 miles from home, when the left cylinder cut out completely. It was also now very mechanically noisey.
This morning I checked the valve settings. The left inlet had nearly 1/4 inch gap!
I took off the rocker box, and found serious wear on the alloy push rods, the alloy had smeared back along the rod. I can't see any other obvious damage, the rockers and followers all look good, and the oil supply is ok.
One of the shorter pushrods is 1/4 inch shorter than its fellow.
Are the alloy push rods susceptible to this sort of problem?

Thanks
   

[a10 gf]

This looks familiar > http://www.a7a10.net/forum/index.php?topic=7864

I found that one of the gaps was 1/4 inch on the exhaust valve

[duTch]

 This's freakin' me out- when I discovered I had one (slightly) bent steel pushrod, I bought a new set of ' Dural ' rods....well how does one know the difference between dural and ally..??? and what is the standard length of each..I think I gave up on looking for info...??

  So far haven't had any probs. after I rectified the purchased product which was total crappola... I had to equalise them (two long, two short), and then re-profile the ends, which had been 'ground' with 'chines'- like on a boat- ....

NB- especially  'cos I extensively read a10gf's link.....

[u28909z]

I have bought a set of Chromoly Steel ones from SRM(ordered yesterday, received today). They look well made.  Hopefully they will be much better than the poor quality alloy ones.

[BSA_54A10]

when ou get the new rods, carefully check the valve springs for coil bind and naturally the valve itself and the valve guide.
There was most likely some thing other than just poor quality that caused the rod to collapse

[pdy880]

Re pushrod problems.
 I have just experienced the same problem with my super rocket (knackered alloy push rods)
I've put this down to valve springs getting coil bound due to fitting a spitfire 357 cam.
I see Ebor bikes are marketing a special Eddy Dow type kit that could help with this problem
Andy.            pdy880

[wilko]

Probably why all these worn camshafts exist as well.

[terryg]

The Dural pushrods from one of my engines, fitted many years ago but with very low mileage, showed alarming signs of wear at the ends when recently removed.  They will be replaced by a set of tubular steel pushrods with hardened end caps (looking very much like the originals) that C and D supplied (£35 approx.)

The Dural pushrods do make good paint stirrers!

[muskrat]

Funny thing is I've had Dural rods in both my A's for years, even raced the A7SS with never a problem.
Cheers

[pdy880]

        Alloy pushrod problems.   After consulting SRM and Draganfly , it appears that these rods can give problems (rapid wear)
        SRM will not fit them .  Fit the original steel with hardened ends. SRM can supply their own specials for about £58.
        Hope this helps.
            Andy            pdy880

[KiwiGF]

I fitted alloy push rods, supplied by Draganfly, 4000 miles ago and have not needed to adjust the clearances yet, the other post referred to above mentioned there was a known problem with alloy rods having an incorrect radius on the ends which caused them to stick in the rockers, Ive seen those duff rods myself, a friend showed me some he had trouble with, the difference between good and bad radius is not easily seen but might be the cause of the poor reputation of alloy rods?

Ive been told most parts are made by one uk company (yes I do know their name), who only supplies wholesale, hence when they stuff up all suppliers buying from them tend to have the same quality issues, and some suppliers (grrrrr) keep on selling known duff parts until the stock is used up, despite knowing of the issues - the reason being the uk manufacturer will not take the duff parts back under "warranty" that they manufacture.

[Pecon]

You are not alone..!!. I had the same problem when one of the rods melted for want of a better description.

http://www.a7a10.net/forum/index.php?topic=7864.msg55425#msg55425

Changed to a set of steel ones from SRM and no problems since.

Peter