Con rod choice?
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SteveA
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cjandme said:I have no experience with R&R , but have you considered JS Motorsports carillos, check out their website if you haven't alreadygillou said:
Good if you are changing pistons as well.....
But I note when discussing suspension Gillou says he has a tight budget......more standard rods Gillou
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The Norton rods are proven bulletproof in Hogslayer's 150 hp 8000/+ rpm 850's for several record making seasons in a row and recently Ken Canaga land speeder 920 on Nitrous which fractured case some but rods still good to go after decades of use. Rest of Norton is too fargile to sustain must race loads but the rods are over built for it. Of course they break all the time just never the first to go unless some super extreme rpm a few have claimed was why. If still pensive, polish em, shot peen then cryogenic temper which also de-stresses them, same with the bolts too.
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SteveA said:cjandme said:I have no experience with R&R , but have you considered JS Motorsports carillos, check out their website if you haven't alreadygillou said:
Good if you are changing pistons as well.....
But I note when discussing suspension Gillou says he has a tight budget......more standard rods Gillou
Yes, to repair my engine, i find a crankshaft MK3 (standard!!), a cylinder and piston (standard to but i have to verify). I just miss connecting rods. Later I again have to make balance all this.
The R&R rod are cheapper than Andover Norton Rod and certainly than Carillo ?
That to choose?
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Salut Gillou and All,
If you consider using JS stuff (Carillo conrods, lightweigh pistons, lifters etc...) just get in touch with me if you want my opinion.
I use them in my 1972 750 Commando engine and I'm really delighted with the result.
Here is my e-mail address:
lmhusquin@orange.fr
Cheers,
L.
If you consider using JS stuff (Carillo conrods, lightweigh pistons, lifters etc...) just get in touch with me if you want my opinion.
I use them in my 1972 750 Commando engine and I'm really delighted with the result.
Here is my e-mail address:
lmhusquin@orange.fr
Cheers,
L.
Chris
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Hi Gillou
My Maney 750 engine runs standard rods. On the bigger engine I run corrillo rods.
If I was building a 750 I would run "Lightning" alloy rods £ 135 each,
Bigger I would use these
http://www.ebay.co.uk/itm/Norton-Comman ... 3a994f9810
Running on a budget ie skint means you sometimes don't get out as you wait for good stuff to turn up at the right price. However the above rods are as cheap as stock.
Chris
My Maney 750 engine runs standard rods. On the bigger engine I run corrillo rods.
If I was building a 750 I would run "Lightning" alloy rods £ 135 each,
Bigger I would use these
http://www.ebay.co.uk/itm/Norton-Comman ... 3a994f9810
Running on a budget ie skint means you sometimes don't get out as you wait for good stuff to turn up at the right price. However the above rods are as cheap as stock.
Chris
Chris
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The R&R rods are similar to the Thunder Engineering ones - machined from billet aluminium.
They're certainly good quality and I guess it's down to which one is cheaper. The R&R look to be around £200 each?
I put a set of the R&R rods in my 1970 Proddy Racer engine, and had to relieve the crankcases a little to clear the ARP con-rod bolt heads
I can't vouch for their performance as I haven't run the engine yet... too many other projects!
I don't doubt they'd be strong enough - the blurb states:
R&R Con Rods are used in top fuel engines producing in excess of 8000 horsepower.
The alloy used is extruded bar and is upwards of 90,000 psi tensile strength.
R&R Con rods are used in Monster Trucks, Drag Racing and Nascar.
Supplied with 3/8" A.R.P 2000 automotive rod bolts with a tensile strength of 190,000 lbs.
They're certainly good quality and I guess it's down to which one is cheaper. The R&R look to be around £200 each?
I put a set of the R&R rods in my 1970 Proddy Racer engine, and had to relieve the crankcases a little to clear the ARP con-rod bolt heads
I can't vouch for their performance as I haven't run the engine yet... too many other projects!
I don't doubt they'd be strong enough - the blurb states:
R&R Con Rods are used in top fuel engines producing in excess of 8000 horsepower.
The alloy used is extruded bar and is upwards of 90,000 psi tensile strength.
R&R Con rods are used in Monster Trucks, Drag Racing and Nascar.
Supplied with 3/8" A.R.P 2000 automotive rod bolts with a tensile strength of 190,000 lbs.
lcrken
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This is probably a little controversial, but here goes anyhow. I wouldn't recommend an all-aluminum rod for long term use in a Norton. They might be ok for drag bikes because the total running time is so short that they don't get to their fatigue limit, and some folks think they have better shock absorbing qualities than steel rods. But for long term street use in Nortons, they do seem to have a problem with the big end getting oval shaped. Most of the load on the big end is on the cap, when the piston changes direction at TDC, and the aluminum cap doesn't seem to hold up to that. The stock design with an alloy upper for light weight and a steel cap for strength seems to me like a really brilliant design compromise. Rod makers have generally added more material to the big end to try to keep it round, and that might work. I don't have enough experience with them to offer an opinion. But I have seen a couple sets break in vintage racing Triumphs and Nortons. That was some years ago, and maybe the designs have improved since, but I'd still go with stock rods or Carrillos. I've also talked to Jim Comstock, who has a lot more experience with them than I do, and he says he's never been able to find an aluminum rod that will keep the big end round in use.
Regarding their use in NASCAR and drag racing engines, all the NASCAR engines I've seen use steel rods. And top fuel dragsters that use aluminum rods replace them regularly, sometimes after only one run, so I don't see that as a recommendation for long term street use. The big difference between aluminum rods and steel rods, besides the big end concentricity issue, is that aluminum rods can reach their fatigue life limits in normal usage, where steel rods don't.
On the other hand, if you really want to go with an all aluminum rod, I have a pair of new ex-Kenny Dreer rods that I'd sell for a lot less than R&R prices. I haven't put them up for sale yet, because the small end seems a bit tight to me for stock pins, and I need to check that more closely, and maybe have them honed out for the right fit, and haven't got around to that yet. I'll eventually be putting them in the for sale section, but if you're interested, drop me a pm. I don't know who made them, but here's a picture. Maybe someone will recognize them and post the info.
Ken
Regarding their use in NASCAR and drag racing engines, all the NASCAR engines I've seen use steel rods. And top fuel dragsters that use aluminum rods replace them regularly, sometimes after only one run, so I don't see that as a recommendation for long term street use. The big difference between aluminum rods and steel rods, besides the big end concentricity issue, is that aluminum rods can reach their fatigue life limits in normal usage, where steel rods don't.
On the other hand, if you really want to go with an all aluminum rod, I have a pair of new ex-Kenny Dreer rods that I'd sell for a lot less than R&R prices. I haven't put them up for sale yet, because the small end seems a bit tight to me for stock pins, and I need to check that more closely, and maybe have them honed out for the right fit, and haven't got around to that yet. I'll eventually be putting them in the for sale section, but if you're interested, drop me a pm. I don't know who made them, but here's a picture. Maybe someone will recognize them and post the info.
Ken
lcrken
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You also might want to read this bit from the R&R rod site.
"How often do I need to change my aluminum rods?
As mentioned before, an aluminum rod acts like a shock absorber. There are only so many cycles even a shock absorber can withstand before it can't rebound further. Even though many customers say our rods last longer than other aluminum rods they have used in the past, this totally depends on the application and how the engine is treated. The best we can do is report back what our customers tell us. In street use, people report over 15,000 miles of mixed street/strip use on applications with high boost. The key is to replace the rod before it fatigues, so it's best to speak to your engine builder or search the internet forums for what other people are reporting."
and maybe this one too.
"Can an aluminum rod be rebuilt?
While yes we can resize both the pin end and the big end of the rod, usually aluminum will stress fracture long before this is needed and should be replaced as a maintenance item."
Ken
"How often do I need to change my aluminum rods?
As mentioned before, an aluminum rod acts like a shock absorber. There are only so many cycles even a shock absorber can withstand before it can't rebound further. Even though many customers say our rods last longer than other aluminum rods they have used in the past, this totally depends on the application and how the engine is treated. The best we can do is report back what our customers tell us. In street use, people report over 15,000 miles of mixed street/strip use on applications with high boost. The key is to replace the rod before it fatigues, so it's best to speak to your engine builder or search the internet forums for what other people are reporting."
and maybe this one too.
"Can an aluminum rod be rebuilt?
While yes we can resize both the pin end and the big end of the rod, usually aluminum will stress fracture long before this is needed and should be replaced as a maintenance item."
Ken
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I checked on the all Al rods when M.A.P. Cycle 1st offered them to find out the Al cap size needed some case relieving to use. The engines that mainly benefit from the springiness of Al rod are those that run with lots of detonation and are sacrificed each run to allow the crank and its supports to last a run too. If the Al part such as rods are made beefy enough for the loads expected, such as Norton rods, there is no fatigue life limit. So far as I know no Norton engine has over powered Norton rods, something else lets go first. My personal evidence is from the 9000 P!! dragster and Ms Peel stuck throttle that stumbled me back twice from isolastic smacking to recordable rpm but rod survived fine though crank bent, cam lobe wiped off, oil pump snout fracture and RM cam tension turned to chewing gum pieces. If JSM had not come up with his light wt kit same Norton rod would be taking the big block hi CR Doruin. If ya can afford it get JSM kit if not don't sweet it.
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It's worth noting that BSA A65s have all-alloy rods, and with far less material around the big-end, but if it's a race motor the above advice would seem to be more relevant!
I'm still pretty relaxed about the R&R rods in my PR motor, which is being built for track days and possibly racing if funds will allow (ever!)
I'm still pretty relaxed about the R&R rods in my PR motor, which is being built for track days and possibly racing if funds will allow (ever!)
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Ken Much as I don't know much about Nortons I am not convinced your examples are valid w/o knowing what engine failures those rods had endured prior. With my limited back ground I'd suspect over heating piston binding in lower bores or crank flex levering through journals fracturing rods from miss angled forces. Yet as I don't know for sure I'm glad for JSM rod/piston kit in Peels expensive experiment. I reflect on how freaking hard past racers have gone on factory rods. If Peel had not over rev'd so much I'd gone with those rods and would like em back to reproduce last Peel's Combat engine again for a chopper or light boat towed behind next Peel or in her side car rig. Cases seem to give up before factory rods if nothing else does first.
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I raced with original alloy rods and they survived. But not everyone has- been so lucky. Below is an alloy rod out of the French "yellow peril" racer that destroyed the motor. Doug M had a couple race motors destroyed with original and aftermarket alloy rods. You save your money and you take your risks.
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' I've also had a stock steel Norton rod break in a short stroke 750, primarily due to the extra acid dip lightening that the factory mistakenly tried for weight saving.'
Are you saying the failure was due to hydrogen embrittlement ?
I use aluminium rods in my 850 motor, however the piston weight worries me. With the rebalanced crank and the way the motor is set up using methanol, it spins up extremely quickly as it comes up through the gears, even when the overall gearing is high. I always try to keep the revs below 7000 RPM, however it is not easy. Piston weight and those aluminium rods were the main reason I was always reluctant to race the bike. I simply did not believe in it. In fact the only reason I raced my 500cc short stroke Triumph for all those years was that it was almost indestructible.
Are you saying the failure was due to hydrogen embrittlement ?
I use aluminium rods in my 850 motor, however the piston weight worries me. With the rebalanced crank and the way the motor is set up using methanol, it spins up extremely quickly as it comes up through the gears, even when the overall gearing is high. I always try to keep the revs below 7000 RPM, however it is not easy. Piston weight and those aluminium rods were the main reason I was always reluctant to race the bike. I simply did not believe in it. In fact the only reason I raced my 500cc short stroke Triumph for all those years was that it was almost indestructible.
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