What's the real deal with "D" rods?

Status
Not open for further replies.
J

john robert bould

Joined
Sep 26, 2009
Messages
2,210
My MK 3 1976 as 6000 miles, i am told the motor could have "D" rods,and could self destruct any time.
As any one had this happen , with " normal" road use. :?:
 
Andy
Who do you think told me :?: This double stamping business,is behond my thinking, i have seen a black smith working iron, with many stampings..so whats the differance?
uote="B+Bogus"]Ask Les Emery :mrgreen:[/quote]
 
Les Emery started the whole D rod thing, and his reputation is pretty poor. It all started with him and you will probably not find any information out there first-hand from anyone having any trouble with them.

Most questions like this have already been beaten to death on this forum so the first thing to do is to run a search and read what you can find from those here who have that first hand experience and not the dozen or so arm-chair experts that always clog threads up with hearsay, good luck.
 
Beng, Yes i agree about the hearsay, thats why i asked for the "REAL DEAL" i have not concluded 100% positive info from this site so far...i just want some member to chime in with " I have done 50000 miles,and no issue's yet" and some times red line the motor! Les Emery told me (face to face] these "d" rods fling apart around 12k , he said he as banged one on the bench and it fell into two bits, i personaly cannot see that happing...but i have no evidence to dis claim this claim.
I know the forum as beaten this to death....but who as done the "Business" with these Rods?


beng said:
Les Emery started the whole D rod thing, and his reputation is pretty poor. It all started with him and you will probably not find any information out there first-hand from anyone having any trouble with them.

Most questions like this have already been beaten to death on this forum so the first thing to do is to run a search and read what you can find from those here who have that first hand experience and not the dozen or so arm-chair experts that always clog threads up with hearsay, good luck.
Click to expand...
 
john robert bould said:
Andy
Who do you think told me :?: This double stamping business,is behond my thinking, i have seen a black smith working iron, with many stampings..so whats the differance?
uote="B+Bogus"]Ask Les Emery :mrgreen:
Click to expand...
[/quote]

I suspected as much :roll:
Sorry to say I can't provide any personal experience - my youngest Commando is a '74
I mentioned the D rod thing to Mick Hemmings last year, and he was clear that there's nothing wrong with them.
It wasn't all he said, understandably, but you get the gist :wink:
As an Engineer, you've already caught the problem with L.E.'s theory - a forging is a forging. One big thump and it's off to the machine shop.
Perhaps he could show you his collection? I always keep my mechanical horror stories!

What a great way to introduce doubt and confusion, though... especially when the solution requires the customer to stump up... lots :cry:
 
THE Real deal is we have never heard heard of a Norton rod of any type being the weak point in engine failures and plenty of D rods still running w/o a series of horror tales reported regularly. Even if the D rod is a weaker rod version its still over built for the Norton long runs w/o a fatigue limit in normal level engine build and operation. Of course you can break a rod by cracking it over a corner on something, shoot just think of how much care the surface finish is to stress risers so a stupid-ignorant way to demo someones opinion with questionable motives. The real danger is just getting on starting it up to expose to fates.
 
My mates low mileage D rodded Mk3 broke a rod, ended up with with 3 piece crankcases broken barrels and damaged cam,2 up doing about 40 mph. Make of this what you wish but also 2nd hand knowledge of another doing this just after being sold to a policeman makes me tend to agree with Mr Emery.
 
That sure sucks to read snakes but just finding broken rods does not mean they are what failed first. If in doubt mount D rods on wall as proper thing to do and not pass on to some unsuspecting builder then spend what makes ya comfortable as can find which ever side of the assumed logic points to guide choices. Inspected examined then cryogenic tempered fasteners 'torqued' by stretch measure is what I'm doing for my factory rods piece of mind.
 
If you over rev a motor once and stretch a rod into its plastic zone, it can let go at any time. Double stamping a steel forging can cause a 'lap', aluminium forgings are not made that way.
 
Note that the tall tales of D rod failure thrown up as proof occurred at low sane rpm and loads or cracked across an edge so tosses rpm over load out the logic window for me. Crank may flex and bind rod ends, bolts may let go and pistons come apart or valves float and clash but the last to go are the tough ole Norton rods mis directing attention and worry.
 
I don't know much about this "D" rod "issue", but it would seem that if it were a real problem it would be occurring at a higher rate than what is described here, especially if it were a rod forging flaw. In my experience, when rods fail, they fail for reasons other than the rod itself. Usually bearing failure is the culprit. Bearing seizure due to wear or lack of oil busts the rod. It would be interesting to see actual pictures of the bearings and crank journals on these suspect rods. That should show little or no damage to the crank journal or bearing and in fact the lower portion of the rod might stll be connected to the crank. Has anyone seen any actual pictures of one of these failures?
 
The "D"-rod saga is but a saga stemming from a ham-fisted mechanic in the late 1970s who blamed his- predictable, given his abilities- recently-rebuilt-engine failure on the rods.

So Nick Hopkins, Norton factory man pre-Andover Norton, then Andover Norton man from Day 1, who knew the man, told me. And I well believe it, having seen rod failures very rarely since I started dealing in Norton spares in 1978- and, remember, the dealer sees mainly the catastrophies!

So I agree with Mick Hemmings, whose judgement I rate-from other experiences with him- above all other English "specialists". There is nothing wrong with the "D"-rods. Personally would not hesitate to put one in my engines. In fact, one or more of them may have them inside them!

Joe/Andover Norton
 
In all due respect but this is not the "real deal"....your mates engine failure could be anything, oil failure,piston tightening up. over reved ...etc...if Mick Hemmings is OK with the rods...then that is the real deal...as Joe states it's all hearsay...No one as yet stated high milage on the "D" rods, which is strange?




snakehips said:
My mates low mileage D rodded Mk3 broke a rod, ended up with with 3 piece crankcases broken barrels and damaged cam,2 up doing about 40 mph. Make of this what you wish but also 2nd hand knowledge of another doing this just after being sold to a policeman makes me tend to agree with Mr Emery.
Click to expand...
 
When I had the lower end apart on my MKIII, it was well before I'd ever heard of the D rod thing. My rods looked great, it was a low mile engine, left the factory main bearings and put in new rod shells. At that time, the INOA Tech Digest was my "Bible" for things Norton, and it said all Commando rods were strong if in good condition. So, I just put it together and that's that. I suppose next time I have the top end apart, I'll see if these are the dreaded D rods. If the damn thing breaks a rod today when I ride it, can't say I wasn't warned, but I don't think it will. Les Emery snapping a D rod against his counter carries some weight, but Mick Hemming saying there is not a problem with them also does. What's a mother to do?
 
Well i carn;t see Les and Mick comming to an agrement over a pint :lol: My MK 3 is a genuine 6000 miles from new and never been apart since it left the factory, and i kinda like that, Les said "just wipe the head and cylinder off" ,,the engine is bone dry ...apart from a drip from the taco drive..i bet once the parts have been disturbed it will have oil issues. :?: :!:
 
john robert bould said:
Well i carn;t see Les and Mick comming to an agrement over a pint :lol:
Click to expand...

Certainly true!

I recently took delivery of a tacho housing from Andover Norton and it was fitted with a proper garter seal - can't remember now if it was listed as a special item or not.

That's the only place my 850 has leaked from since I rebuilt it a few years ago, so hopefully, fully oil-tight from now on... :|
 
Andy, as you are a [was] a aircraft fitter :?: if you carn't make a commando engin oil tight .then god help the "shoe salesmen" who attempt rebuilds :!:
 
There must be lots of low mileage D rods hanging on walls?
My '77 had only 1 D rod and it is now hanging on the wall.
I read the story an changed it, it had 12k miles on it.

Graeme
 
Status
Not open for further replies.

Similar threads

bushman
  • Locked
The real story of an Indian made gas tank...
2
Replies
26
Views
8,508
XTINCT
XTINCT
Snorton74
What's the deal Norvil?
Replies
3
Views
900
grandpaul
grandpaul
W
  • Locked
What is the deal with Keihin carbs? (2011)
2 3 4
Replies
62
Views
8,711
Steves
Steves
tpeever
  • Locked
should I be worried about "D" rods?
Replies
8
Views
2,392
ZFD
ZFD
B
  • Locked
What's the deal with pre-1971 Commando's?
Replies
6
Views
820
DogT
DogT
Back
Top