Alternative con rods

[CheeserBeezer]

Thank you to all those who responded to my other thread about the hole in the left hand con-rod. This has led to another topic, i.e. 'Alternative Con Rods'. It may be that everybody has said what they want to say but, to keep things tidy, it may be worth repeating here. I've just bought some 'Lightning' Rods from Thunder Engineering. They have a number of benefits over the original rods. 1) ..and obviously, they are brand new so no damage or stretch or cracks which may or may not be present in the original rods. 2) They don't use small end bushes so no chance of reaming them crooked and 3) They come predrilled with the oil squirty hole which some other aftermarket rods don't.
My only other experience with aftermarket rods is the R+R rods which appear to be about 0.8 mm too long and don't have the squirty hole. Has anybody fitted these...with success?

[Tomcat]

Interesting topic thanks CB.
I bought Thunder con rods for my Commando but they are bigger than standard and had to have material removed so they didn't hit the crankcase. The pics of the A10 rods in the other thread look like they fit straight in with no mods??

[Kickaha]

I bought MAP for the A10 I am building, forged steel

[berger]

Tomcat my thunder rods went straight in my A7 but didn't come pre drilled they must have started drilling them. my brother said it was tough stuff when he drilled mine in the mill. i don't know about them going straight in a A10 though, but they were made 6 years to the date after my heart attack, i phoned them up and we had a laugh about it. they date them across the big end cap and rod.

[CheeserBeezer]

Tomcat my thunder rods went straight in my A7 but didn't come pre drilled they must have started drilling them. my brother said it was tough stuff when he drilled mine in the mill. i don't know about them going straight in a A10 though, but they were made 6 years to the date after my heart attack, i phoned them up and we had a laugh about it. they date them across the big end cap and rod.

I had a chat with Mr Thunder Engineering (Steve Campbell?) who was very helpful. He didn't suggest that the rods needed modifying in any way. the note that comes with the rods says that, in some case, it may be necessary to shave a bit off the bolts if they catch the inside of the crankcases. I think this is a generic note which they put in with all their con rod kits.

[chaterlea25]

Hi All,
I have a set of older MAP alloy rods waiting to go in the RGS project engine,
The crank has been balanced to suit.
They do not have the oil hole, and this and the other topic brings up the argument for and against drilling  to the fore again.

The subject engine has the roller ts roller bearing and end fed conversion, this conversion stops the leakage from the ts main being flung up into the piston..this leaves the oil escaping from the big ends as the source of bore lube and cooling which should be equally spread between the cylinders,
I have not studied at what angle of the crank the rod and crank oil holes line up?
So wonder where this supposed short squirt of oil is pointed to?

To drill or not to drill that is the question

John
 

[roadrocket]

I put Thunder rods in my RR, they went straight in without need for dressing the bolts. They are heavier than standard, but the engine is at least as well balanced as with the standard rods.

[berger]

i think it's do as you wish regarding the hole after reading lots about this and people not drilling the rod. it has been shown in BSA service sheets about drilling the rod and it is drilled at 30 degrees down the rod to match up with the hole in the shell, the drilling is 3/64ths . some say to increase flow some say to spray the barrel, some say they run there bikes without the hole with no problems . some say don't drill it but file a wide slot either side of the rod to let oil squirt up those slots to the cylinder. all i know is some people have put the rod on with the oil hole facing the drive side bearing with no problems. another thing i know apart from bggr all is that i haven't been to the pub for longer than normal , so on monday i am going to the PUB!

[RDfella]

Yes, though mine didn't come with drilled hole. Material is so hard (presumably work-hardened) nearly impossible to drill.
Substantial rods, but be prepared to re-balance the crank, as they're appreciably heavier than originals.

[berger]

RD fella that's what my brother said when he drilled my thunder rod