mikeyb Posted September 11, 2008 Share Posted September 11, 2008 RBRR last minute prep has dictated that the engine has come out of the PI! Today, I'm taking the flywheel into work and intend to get it lightened. I have a copy of Vizards tuning book which shows where to machine, but the question is "how much"?I'm told that GT recommends 6kg? That sounds a lot (13LBs). It's the heavier Mk2 flywheel, weighing around 28LB on my dodgy scales!CheersMike! Link to comment Share on other sites More sharing options...
JohnD Posted September 11, 2008 Share Posted September 11, 2008 Mike,Why do you want to lighten the flywheel for an endurance event?Lightened flywheels are for race, sprint and drag racing, to improve acceleration, fractionally.The RBRR is none of these, in fact is specificly NOT a race. The middle name of the event and secret of success is reliability, which you sacrifice by doing this.Seems to me a foolish mod.John Link to comment Share on other sites More sharing options...
Jason Posted September 11, 2008 Share Posted September 11, 2008 I don't think it's in preparation for the RBRR John, more like it's conveniently off the car as a result of the RBRR prep :-) Link to comment Share on other sites More sharing options...
Richard B Posted September 11, 2008 Share Posted September 11, 2008 MikeyB wrote:Today, I'm taking the flywheel into work and intend to get it lightened. I have a copy of Vizards tuning book which shows where to machine, but the question is "how much"?I'm told that GT recommends 6kg? That sounds a lot (13LBs). It's the heavier Mk2 flywheel, weighing around 28LB on my dodgy scales!That does sound extreme (but that's GT), I think CW gets 7lb taken off, down to 21lb. John the MkII flywheel is signifigantly heavy compared to everything else. It was intended to help the MkII act as a tow car. But it really 'slugs' the engine. Compare the Saloon flywheel to a GT6 or Vitesse one.The MkI PI flywheel is lighter due to the longer crank extension. Link to comment Share on other sites More sharing options...
99176 Posted September 11, 2008 Share Posted September 11, 2008 Hope you have it rebalanced before you re-fit. Link to comment Share on other sites More sharing options...
Slimboyfat Posted September 11, 2008 Share Posted September 11, 2008 JohnD wrote:Mike,Why do you want to lighten the flywheel for an endurance event?Lightened flywheels are for race, sprint and drag racing, to improve acceleration, fractionally.The RBRR is none of these, in fact is specifically NOT a race. The middle name of the event and secret of success is reliability, which you sacrifice by doing this.Seems to me a foolish mod.JohnThe wife's shopping car (2.5 PI) has had a seriously lightened flywheel (in fact thinking about it most of our cars do) fitted for the last 10 years or so. I never considered it a foolish mod only fit for a drag racing sprint car. Her PI is a docile little puppy that she takes the kids to school in. The flywheel in her car is radically lightweight having originally come from a banger racer car, much lighter than anything we have ever sold, or fitted to a customers car. One of my road cars has an aluminium flywheel that to is docile and idles smoothly, and without drama. Triumph flywheels ARE TO HEAVY! Link to comment Share on other sites More sharing options...
mikeyb Posted September 11, 2008 Author Share Posted September 11, 2008 I'm swapping engines prior to the RBRR as WJE's bottom end is shot. I've bought Clive's spare TR6 engine so that's what's going in. It's a short nose crank with the heavy flywheel - just weighed in at 27Lbs! As others have said above, it's well known that the 2.5L engines become more responsive when the excess flywheel weight is removed - with ehngine and gearbox on the garage floor, now's the time to do it!We've been looking at where to shave metal off but it's not obvious to me where even 7lb can be lost. Have looked in Vizards tuning book, it's got a good sectional drawing but that looks to be of the earlier lighter flywheel.So . . . where do we machine? Link to comment Share on other sites More sharing options...
Richard B Posted September 11, 2008 Share Posted September 11, 2008 MikeyB wrote:So . . . where do we machine?Scooped out of the back; personally I'd say give CW some beer tokens. But I'm sure you would like a cheaper answer ;) Link to comment Share on other sites More sharing options...
Deleted User Posted September 11, 2008 Share Posted September 11, 2008 Very good question and a discussion I'd like to listen to.These are Chris Witors words on the subject."Flywheel - It is highly beneficial to acceleration in the lower gears to have the flywheel lightened. 7lbs can safely be removed by turning in a lathe and a further 3lbs by slotting in a milling machine, which takes the weight (less ring gear) down from 25lbs to 14lbs. An aluminium flywheel weighing 12lb 4oz is available on request, but currently costs nearly £400.00."It's something I've been considering since I have my old engine in the garage. I thought I could get that flywheel lightened and then swap it over when convenient. Only thing is I'm not sure how much I should be paying to get it lightened and how much is ideal to have removed. Surely a certain wieght is beneficial for cruising, although I'd place more importance on easier acceleration for town driving. So what's a happy medium and is it worth doing. Link to comment Share on other sites More sharing options...
andy thompson Posted September 11, 2008 Share Posted September 11, 2008 Make sure you balance it!!!!!! Link to comment Share on other sites More sharing options...
mikeyb Posted September 11, 2008 Author Share Posted September 11, 2008 thanks, I will. Have already been in touch with the balancers, they said the pressed steel clutch covers are the biggest inducers of imbalance, so I intend to get em done together!I seriously thought of the CW option (just under £100 for an exchange lightened flywheel) but I would still have had to balance that and the clutch anyway. Link to comment Share on other sites More sharing options...
piman Posted September 11, 2008 Share Posted September 11, 2008 Hello Mikey, the most effective weight reduction is at the largest diameter, so that is the area to attack. Do be aware that too much can weaken the flywheel and cause it to burst with possible serious consequences. (Which is why racing engines often use steel as opposed to the standard cast iron flywheels as steel is so much stronger.)Alec Link to comment Share on other sites More sharing options...
JohnD Posted September 11, 2008 Share Posted September 11, 2008 Don't care what you say, it's foolish to make radical mods just beforehand when the RBRR is about reliability.What's your car number Mikey? I'll watch your progress with interest and buy you a pint at the finish, IF you make it before the Acclaimers.John Link to comment Share on other sites More sharing options...
mikeyb Posted September 12, 2008 Author Share Posted September 12, 2008 Fair comment, but flywheel lightening is not what I'd call radical! The hot oil pressure at 70mph on the old engine had dropped to just over 20psi, due to the wear in the crank/shells, so using the original engine as is was not an option. If I had gone for a bottom end rebuild which had been Plan A, I would still have attacked the flywheel. If there is time, I'll be doing a Power Steering conversion and may even fit a TR6 manifold/downpipe.In 2006, we plucked a Mk1 2000 from the jaws of the scrappy, spent 6 weeks fighting to rectify all the horrendous bodges that had been carried out to it's mechanics and get an MOT, She would barely run, stop, steer etc and was so unreliable had to to to the MOT on a trailer as she'd conked out on the way to 2 previous in quick succesion! We we lying on the drive in torrential rain on the Friday afternoon refitting the steering rack. The old girl made it round in 51 hours and never missed a beat, then went on to do another 6k miles that year in daily use.Personally, I thrive on the pressure of prepping a car before a big CT event, in my busy life I need a target to get the big unwlecome jobs done. Thanks to CT, I've recomissioned 3 cars that would otherwise remain languishing in long term storage, and have done some fairly major much needed mechanical work on a few!Bring it on!Oh and I'm No.34 :-) Link to comment Share on other sites More sharing options...
Slimboyfat Posted September 12, 2008 Share Posted September 12, 2008 MikeyB wrote:thanks, I will. Have already been in touch with the balancers, they said the pressed steel clutch covers are the biggest inducers of imbalance, so I intend to get em done together!. That's been our experience to, little point in balancing a flywheel without including the clutch cover (that you are going to use!) at the same time.Having said that back in the day when I was young and had time on my hands I used to play with flywheels and laithes regularly in attempt to get my otherwise standard TR5 to do sub 16 second quarters at Santa Pod. Back then I never had the money or the inclination to get someone to balance them for me. Hand on heart those things used to be turbine smooth and would last a couple of seasons weekend drag racing before a new set of shells were required. Now I pay for someone else to lighten our flywheels, if nothing else it saves sweeping up the mountain of swarf produced from the workshop floor. Link to comment Share on other sites More sharing options...
Slimboyfat Posted September 12, 2008 Share Posted September 12, 2008 MikeyB wrote:Personally, I thrive on the pressure of prepping a car before a big CT event, in my busy life I need a target to get the big unwlecome jobs done. Thanks to CT, I've recomissioned 3 cars that would otherwise remain languishing in long term storage, and have done some fairly major much needed mechanical work on a few! :-)I agree that's what motivates me as well. Most of the cars (vans?) I currently have MOT'd wouldn't have seen the road (realistically) without the RBRR, or the 10CR to give me a kick up the arze. Long live CT and its endurance rallies they are (mostly) responsible for my fleet of roadworthy Triumphs (and Standards?). Link to comment Share on other sites More sharing options...
mikeyb Posted September 12, 2008 Author Share Posted September 12, 2008 Having never done this before I'm paranoid of taking too much off in the wrong place and weakening it! We're now 2LBS down, having skimmed approx 3mm of the thick bit to the rear of the flywheel. I aim to take 6LBS off - how thin do you think I can go? Link to comment Share on other sites More sharing options...
Richard B Posted September 12, 2008 Share Posted September 12, 2008 MikeyB wrote:Having never done this before I'm paranoid of taking too much off in the wrong place and weakening it! We're now 2LBS down, having skimmed approx 3mm of the thick bit to the rear of the flywheel. I aim to take 6LBS off - how thin do you think I can go?Quite deep, leave a radius at both ends. So you are looking at about a centimeter to get 7lbs off or should I say 3/8'' in English money! ;) Link to comment Share on other sites More sharing options...
ferny Posted September 12, 2008 Share Posted September 12, 2008 JohnD wrote:What's your car number Mikey? I'll watch your progress with interest and buy you a pint at the finish, IF you make it before the Acclaimers.JohnYou make it sound like a race! ;DNow all you need to do is slap Mikey on the face with a soft cotton glove to confirm the challenge. Link to comment Share on other sites More sharing options...
James Posted September 12, 2008 Share Posted September 12, 2008 Looking forward to photos of the new frisbee (without the flying connotations) Link to comment Share on other sites More sharing options...
JohnD Posted September 12, 2008 Share Posted September 12, 2008 MikeyB wrote:Fair comment, but flywheel lightening is not what I'd call radical! The hot oil pressure at 70mph on the old engine had dropped to just over 20psi, due to the wear in the crank/shells, so using the original engine as is was not an option. If I had gone for a bottom end rebuild which had been Plan A, I would still have attacked the flywheel. If there is time, I'll be doing a Power Steering conversion and may even fit a TR6 manifold/downpipe.In 2006, we plucked a Mk1 2000 from the jaws of the scrappy, spent 6 weeks fighting to rectify all the horrendous bodges that had been carried out to it's mechanics and get an MOT, She would barely run, stop, steer etc and was so unreliable had to to to the MOT on a trailer as she'd conked out on the way to 2 previous in quick succesion! We we lying on the drive in torrential rain on the Friday afternoon refitting the steering rack. The old girl made it round in 51 hours and never missed a beat, then went on to do another 6k miles that year in daily use.Personally, I thrive on the pressure of prepping a car before a big CT event, in my busy life I need a target to get the big unwlecome jobs done. Thanks to CT, I've recomissioned 3 cars that would otherwise remain languishing in long term storage, and have done some fairly major much needed mechanical work on a few!Bring it on!Oh and I'm No.34 :-)Fair enough, mikey! I'm impressed by such dedication, but as they say, to finish first, first you have to finish. Not that the RBRR has any competitive component at all. Oh, no, it hasn't!The Acclaimers are No.71 - see you at the start line!Hope at the finishing line too??John Link to comment Share on other sites More sharing options...
Greeks Posted September 12, 2008 Share Posted September 12, 2008 Oh no, not the Acclaimers again ... I remember cruising past those boring bastards in 2004... before stopping several times to fix bits along the way. Where's the challenge in driving around the country in a Honda... Link to comment Share on other sites More sharing options...
Deleted User Posted September 12, 2008 Share Posted September 12, 2008 Greeks wrote:Oh no, not the Acclaimers again ... I remember cruising past those boring bastards in 2004... You must have been dreaming it - "The Acclaimers" first RBRR was 2006.[Sorry, album link no longer available]And yes, we too had a repair or two to make along the way Link to comment Share on other sites More sharing options...
mikeyb Posted September 12, 2008 Author Share Posted September 12, 2008 In '06 I had very little confidence that we would make it, but Gertie did us proud. We were near the back most of the way, missed all the pies at Morrisons (Jason?) and were 2nd from last at the finish. We were a little late at the Plough due to last minute repairs, then soon after the start made a big detour for fuel, and found that we couldn't cruise at much more than 70mph due to tha amount of heavy spares carried. Then being near the back, we continually came accross the various breakdowns and lost more time stopping at each one to offer assisitance!This year I have a lot more confidence - the Mk2 is a veteran of 3 Dutch Night Rallies, 2 LCC's, several Bedford CC events, Le Mans, Glastonbury and even this year the Kirkby Londsdale MC Lt Devils Tests . . and has covered around 12K since the last MOT!The replacement engine is a slight unknown (although comes well vouched for) and I need to dig out a couple of reliable fuel pumps as the one on the car at the moment has been a little troublesome recently! I also have a slight worry about how well the Piper Cam it has will match to my metering unit, but we'll see. Now I know how to get an engine out easily, I can always do the bottom end of the oroginal if needs be.Flywheel's done now, too chicken to remove 1cm, it's ended up 4.5Lbs lighter before balancing. Link to comment Share on other sites More sharing options...
Jason Posted September 12, 2008 Share Posted September 12, 2008 MikeyB wrote:missed all the pies at Morrisons (Jason?) Don't you start that Mike! I didn't eat all the pies although I am a fat bar steward :-)Besides, I won't be touching the pies this year, in '06 they upset my stomach and I left them at Morrisons after processing! Link to comment Share on other sites More sharing options...
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