The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Will on 12.04. 2017 22:50
-
I need set of pushrods there only seem to be alloy ones around I would have preferred steel , anyone using alloy ??
-
Have you tried Draganfly Motors, Suffolk. They sold me some last year for my Huntmaster which I BELIEVE are the same.
-
Hi Will,
SRM will have quality steel pushrods
John
-
Mine are alloy. No probs so far.
-
There's a liitle outfit called "SRM" that might have them. Even though they're just a little mom'n'pop shop in the nether reaches of the Welsh countryside, they sometimes seem to have some useful stuff. This year they got 'tricity and hooked up one of them computer thingamajigs. Even have them some advertisin. Look here: http://www.shop.srmclassicbikes.com/product/a10-pushrod-set-chrome-moly-steel-high-strength . If you're lucky, Joe, their mule, will be healthy enough to pack them out into the civilized world.
Richard L.
Some guy named John also seems to have heard of them SRM folks.
-
Mine are alloy. No probs so far.
Mines got 2 steel and 2 alloy (new), after over 6000 miles post rebuild or so I finally got around to adjusting the clearances, only 2 clearances needed tightening by a few thou, the ones with alloy rods. It doesn't bother me but might indicate the alloy push rods wear relatively quickly? *dunno*
-
Modak should have steel pushrods.
Richard
-
SRM pushrods are solid steel (at least the ones I bought from them are) and considerably heavier than the hollow originals. If you fit them, watch your max revs.
-
My alloy pushrods were badly worn at certain points.
Steel replacements had a smaller OD so if you are buying from the Interweb take care.
Cheers, Hadrian.
-
I have SRM steel pushrods.
-
Last year I had a very nasty experience with light alloy push rods - see first photo below. So I would not use them again. The other point was rub marks along the rod which indicated to me that theyhad been flexing.
I then bought a set of original type rods. Wassell make. They were dreadful, the ends were not properly machined - see second photo. They were sent back to supplier. Would not buy rods made by them again.
Finally got a set from SRM which were delivered the day after I ordered them. Top quality. Heavier than standard ones. No rub mraks evident to indicate flexing and I am very pleased with them.
Last photo shows light alloy rod top, next nasty Wassell rod and bottom the SRM one.
-
My alloy pushrods are solid, not tube. I would think steel insert ends into alloy tube like yours would be a recipe for disaster.
-
The ends were bored for the hardened endcap rest of rod was solid.
-
I have SRM steel pushrods. 100% happy. *smile*
-
The solid tapered (thick in the middle) alloy rods in my cafe have withstood 9 years of racing and now another 5 on the road. Might have worn 10thou shorter in that time.
Cheers
Edit. Memory getting shorter too. One set in the A7SS racer then another set when converted to A10RR+ for the road.
-
Last year I had a very nasty experience with light alloy push rods - see first photo below. So I would not use them again. The other point was rub marks along the rod which indicated to me that theyhad been flexing.
I then bought a set of original type rods. Wassell make. They were dreadful, the ends were not properly machined - see second photo. They were sent back to supplier. Would not buy rods made by them again.
Finally got a set from SRM which were delivered the day after I ordered them. Top quality. Heavier than standard ones. No rub mraks evident to indicate flexing and I am very pleased with them.
My experience with replacement ally pushrods was identical. I even had to smooth the end caps by putting them in my drill chuck and shape them with emery cloth. When one broke I bought SRM steel ones; expensive but presumably reliable and well made.
-
The ends were bored for the hardened endcap rest of rod was solid.
i'll say that sucks for starters, and suggest a cap over the ends would be better *????*
I bought Dural rods from somewhere, maybe Kidderminster(?) and ends were F***ed, and had to do similar to GB;
I even had to smooth the end caps by putting them in my drill chuck and shape them with emery cloth.
...but having done that, have done +10K miles, and having checked the clearances occasionally not too much to worry about (so far)
-
I use selfmade alloy pushrods form VW Beetle in all my engines with no problems. They are lighter than the origininal steel ones.
The SRM are in douple the weight and not usefull for racing.
I have a set from this heavyweight SRM pushrods, not long used. If you have interessed to get these let me know.
Cheers Klaus
-
the queston has been covered really, tho heres the notes i made on the topic, copied from various:
- standard steel pushrods: 171.5 grams for a set
- parallel alloy pushrods: 127.5 grams for a set
(but i didn't record the weights of mine - some folk measure their differences as less)
- Dural ones flex like noodles at high RPM's.
- dural push rods - the problem with them was noise. Also don't use on iron head due to different expansion
- chrome molly - More accurate valve timing at high rpm's more than offset the valvetrain weight penalty
I also wondered about higher lift cams and heavier springs loading up alloy rods and flexing them more.
so my conclusion-
steel for road use. maybe alloy if you are a racer or red-liner (tho maybe steel too)
suck it up and pay the srm chrome-molly premium for no -post-purchase regret (or re-machining). worked for me.
-
Now I'm scared Mike! How do we know that the dural ones 'flex like noodles" at high revs?
Then "alloy if you are a racer..." ?
(And can I bear to swap mine out for the original BSA steel ones? Hmmm).
-
How do we know that the dural ones 'flex like noodles" at high revs?
read this thread which summarizes someones testing: http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=195842 (http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=195842)
unless you treat your bikes like Klaus or RR or muskrat you may be overthinking this - if I had original ones that were straight I'd put them back in.
PS my notes are a onenote file with just cut and paste snippets from various sources when I'm stuck with a problem, so i don't have all the sources, but i do have that one *smile*. reading the original and making your own decisions is way better than following my random views.
-
Push rods do flex, engine manufacturers use overhead cams for that reason (and valve train weight). I've often wondered if a 'pull rod' would have been better than a push rod? *eek*
-
I've never had the luxury of high tech (or low tech for that matter) measuring equipment. I use seat of the pants method. My tapered alloy work better than the straight alloy. The alloy being lighter allow the motor to rev up quicker. I have a hill, hit the bottom at 60 and see what I get before the police radar post at the top!!! (my turn off is 100 yards short of them *smile*). I luv grapefruit the missus don't.
A *????* Does any one know for sure what the total length and radius of the original A7 and A10 pushrods was *????*
Cheers
lost a lot of data with last computer crash *rant*
-
Pushrods can and do flex. My uncle put a strobe light on his Rudge so you could observe the external pushrods flex - and they certainly did.