Can a Rocket III take down the establishment, and rule this island

[R-III-R Turbo]

Probably just that I hadn't the tensioner on yet at the time

 

[TURBO200R4]

What were you running, sand racer, mud buggy, sounds like something fun and exciting.

i ran the sand races in early 80's and then built a rail (14 feet?) and moded the car trailer to fit.
chey 373 high compression and two stage nitrous 125 and 275 = 400
650 diff with 36 inch staggered paddles
you could not always see where you were going but you got there pretty dang fast
most of the time it was 100 yards or less

 

[Gerald]

i ran the sand races in early 80's and then built a rail (14 feet?) and moded the car trailer to fit.
chey 373 high compression and two stage nitrous 125 and 275 = 400
650 diff with 36 inch staggered paddles
you could not always see where you were going but you got there pretty dang fast
most of the time it was 100 yards or less

I drag raced gassers from 61-mid 80's. Started with small block Chevy's and stayed with this until early 70's. That's when I built my last car, a 55chevy with a 427 big block with all the bells and whistles. Then built a truck with slide back bed to haul it. My sons wanted to play sports, they didn't have enough coaches, so I coached football, basketball and baseball for sixteen years. I only coached baseball three years, need some time to recharge. The day I sold the car and loaded it on his trailer, I knew I made a mistake.

 

[Gerald]

I have 3500 miles done since the build, the gearbox was feeling a bit awkward and I became paranoid about something breaking, the titanium valve retainers need replacing and I was getting paranoid about how the pistons were doing with all the power and my tuning.
So decided it was high time to tear the engine apart and inspect most stuff, while doing the work above including transmission upgrade (before something broke).
Unlucky that it broke but lucky it was caught before serious damage.

It seems the crank pulley spigot might have held it together, after it fractured.
It might just be plain ol' bad luck and was a weak unit, seeing as nobody has had the issue before that I know of.
But I'm not really happy with just replacing it and hoping for the best.

I do have some very vague recollection of the key being a tight fit, but that was in the crank side rather than the sprocket side iirc.
Have to check my detailed files to see if the sprocket itself was tight going onto the crank nose.
If it was tight, maybe thermal related expansion might have been a factor.
E.g. crank swoll more under heat than the sprocket, and cracked it.

The key appears a bit damaged too (surface damage) so this might be a clue.

FYI Kev I use Nev's tensioner.
Before I buy a replacement timing gear, I'll ask Bill Robinson if he'd make one when doing my transmission.
It would be the same or better than the Triumph one.


A photo of the gear and key after a few thousand miles on the stroker engine, as I was going fitting all the supercharger & Carpenter bits;

Hate this happened to you but thankful you caught it before more serious issues happened. Is that the standard key and keyway or did you increase the size. I've replaced mine a time or two, but I can't remember the size. Think I still have them in parts cabinet. Like the idea of pictures for documentation, better than a thousand words, and you don't have to remember. Thanks for responding to my post.

 

[R-III-R Turbo]

Hate this happened to you but thankful you caught it before more serious issues happened. Is that the standard key and keyway or did you increase the size. I've replaced mine a time or two, but I can't remember the size. Think I still have them in parts cabinet. Like the idea of pictures for documentation, better than a thousand words, and you don't have to remember. Thanks for responding to my post.

It's great to have a few good heads on here to discuss things with.
Especially when the things aren't simple!

Yeah the key was standard size alright, the crank and the spigot have enough meat to go a little bigger but the timing gear unfortunately has no meat left, it is quite thin at that point.

I'm kind of coming to the conclusion that it must be a thermal expansion thing. Since it fractured and then stayed put even when broken.
If it was something else, other than a strange single instantaneous once off event, you'd imagine the broken gear would have been busted up altogether.
Odd though that I had done 5000+miles on the stroker alone, no issues whatsoever, and then when adding the supercharger pulley spigot this happens. Maybe the small added load on the key is merely the straw that broke the camel's back (or the Rocket's timing gear).

I've to take the trans out and ship it off, after that I'm taking the head off to replace Ti retainers so will take the gear off too and see if any more clues.
But I also have a busa here to refit cylinders etc too and little time.

 

[Gerald]

It's great to have a few good heads on here to discuss things with.
Especially when the things aren't simple!

Yeah the key was standard size alright, the crank and the spigot have enough meat to go a little bigger but the timing gear unfortunately has no meat left, it is quite thin at that point.

I'm kind of coming to the conclusion that it must be a thermal expansion thing. Since it fractured and then stayed put even when broken.
If it was something else, other than a strange single instantaneous once off event, you'd imagine the broken gear would have been busted up altogether.
Odd though that I had done 5000+miles on the stroker alone, no issues whatsoever, and then when adding the supercharger pulley spigot this happens. Maybe the small added load on the key is merely the straw that broke the camel's back (or the Rocket's timing gear).

I've to take the trans out and ship it off, after that I'm taking the head off to replace Ti retainers so will take the gear off too and see if any more clues.
But I also have a busa here to refit cylinders etc too and little time.

Once you have chain separated from gear take a real hard look, if a small piece of gear got wedged between the gear and the chain something has to give.

 

[R-III-R Turbo]

So before I pull the head off and have a look further at the timing gear, am taking the trans out to send to Bill Robinson.
Meanwhile some guy in Oz says his timing gear broke before too, also an 06 engine (and stock). But seems a bit sketchy.
If true, then probably no coincidence, must be a few dodgy gears around 06.

First time getting a look at the stroker crank, rods, balancer etc since the bottom end build 8000 miles ago.

 

[R-III-R Turbo]

Oh yes forgot to add, the inner clutch hub inspection.
Good news.
Following this post, where there were cracks forming on the hub with stock bolts, the hub now with the 50mm bolts despite all the low down torque of the supercharged stroker is holding up well;

During build;

Can a Rocket III take down the establishment, and rule this island

Few bits arrived, lockwireable oil filter is a must for race day scrutineering, chromed 100mm pulley looks a bit fancier, break in oil for me new custom made pistons. Booked 2 weeks off for the operation to begin 02-Aug-22, can't wait.

www.r3owners.net

Today;

 

[Gerald]

Oh yes forgot to add, the inner clutch hub inspection.
Good news.
Following this post, where there were cracks forming on the hub with stock bolts, the hub now with the 50mm bolts despite all the low down torque of the supercharged stroker is holding up well;

During build;

Can a Rocket III take down the establishment, and rule this island

Few bits arrived, lockwireable oil filter is a must for race day scrutineering, chromed 100mm pulley looks a bit fancier, break in oil for me new custom made pistons. Booked 2 weeks off for the operation to begin 02-Aug-22, can't wait.

www.r3owners.net

Today;

After seeing your posting a couple years ago I replaced with 50-55 bolts high strength, happy I did. I was replacing flywheel, roller bearing and lifter shaft with updated parts after reading another of your posts. I wasn't happy with the existing old style setup.

 

[R-III-R Turbo]

After seeing your posting a couple years ago I replaced with 50-55 bolts high strength, happy I did. I was replacing flywheel, roller bearing and lifter shaft with updated parts after reading another of your posts. I wasn't happy with the existing old style setup.

Well that's good then. You'd wonder why they changed it, the roller should be better for the heavy side thrust of a pressure plate pull vs a normal single file ball bearing, maybe they couldn't take the rpm or something.

Well I have the trans out now, going to ship to Bill Robinson for the full works.
Stroker crank and rods, balancer etc bearings too all looking good.

Still can't believe Triumph have 2 official ways of removing the input shaft (special tool sliding hammer and coupler, using the bearing housing bolts in the jack lobes to jack it out) when all you have to do is use 3rd/4th gear as a sliding hammer with a couple of light taps and it's out.