Up Into Fourth
Posted 02 August 2022 - 11:26 AM
I have no marked, drilled and tapped all of the outer six screw holes to M5.
I was going to leave the centre in case I needed to rebuild and sell the original trigger wheel, however, looks like I will need to machine out the centre. I have been advised to use a standard crank bolt with these Ali pulley wheels, as people have been having some issues / disastrous problems with the extra long crank bolt coming loose. With the centre intact there is not enough room to fit the socket in.
Up Into Fourth
Posted 02 August 2022 - 12:23 PM
The last task in ensuring that this engine is capable of handling the anticipated power output once the Supercharger is added is the clutch.
Way back three years ago when I started this build, I purchased a MED ST1 kit, thinking it was the dogs cahoonahs. Whilst it is no doubt a well made product, I have since found that "The St1 is only capable of around 70lb.ft torque, so modified 998s or lightly tuned 1275 road engines".
Even without the SC, this engine will hopefully push out around 85ft/lb, so no good anyway. For the anticpated 130ft/lb, I have been advised that I need an RTS (Robert Twin Spring) clutch. Basically, it is a standard clutch pressure plate modified to take an additional set of spring fingers.
Stuart Gurr has made a video here on how to put one together:
In order to ask some more questions I started a thread here.
I picked up a donor clutch from a friend and drill out the rivets to get access to the sprung fingers.
I then did the same to the MED ST1 that I would be modifying.
However, this is when I realised that the "fingers" on the two clutches are different. The set from the older clutch was flatter and at first I thought this was simply as it was an older clutch, however, when test fitting them, the rivet / bolt holes are not in line.
I have now been looking at clutches in a bit more detail and it would appear that the older clutch may have been an AP or AP copy as these seem to have the banded plate under the rivets (along with the two circular rings) whereas the Borg & Beck only has the two circular rings.
So as my balance clutch is a Borg & Beck, I am now desperately looking for a matching set of springs.
Anyway, I punched out the remaining part of the rivet:
And drill using my M8 drill and tap set I drilled and tapped all of the holes and did a dry assemble.
Now due to a manufacturing fault in the Borg & Beck that I purchased, I needed to pack it up and send it back to MED. They said that due to the length of time I have had it, they could not refund or replace it, but would attempt to fix it. Basically one of the holes in the pressure plate that the Flywheel Puller bolt goes through, into the threaded hole in the centre boss behind, is out of centre, preventing the bolt from engaging in it's thread. This would have meant that, had I installed the flywheel and clutch, I would probably have had to cut it off to change it!!
Up Into Fourth
Posted 08 August 2022 - 06:20 PM
Well after failing to find a second hand clutch, I picked up a new (same) Borg & Beck Clutch from Old Skool Minis.
First job remove the rivets. In order to ensure I could get the drilled holes exact centre, I made up a guide on the 3D printer. This simply sits over the rivet and has a 6mm hole.
Once they were all centre punched it was onto the pillar drill.
And once the rivets were tapped with a screwdriver, it was all apart.
Next job, de burr the rivet caps and assemble the springs on my other clutch, the one that has been balance to my crank.
Problem is, now that I have drill tapped fitted some extra lock washers as shims and added another spring, it will all need balancing again. Kieth Calver has offered to do it, so I'll probably have to box it up and send it to him.
Up Into Fourth
Posted 08 August 2022 - 06:22 PM
Last machining job was to take out the centre of the trigger wheel. The lathe really struggled with this so I had to take it in very small stages, ended up taking about two hours!!
Up Into Fourth
Posted 08 August 2022 - 06:29 PM
For anyone reading this as a helpful guide, I fitted the Fuel Pump Blanking plate and was not sure what to torque the bolts up to. Not listed anywhere that I could find.
Anyway, I found this.
16 lb/ft or 22Nm when fitting a fuel pump, so I figured the same for the blanking plate.
Up Into Fourth
Posted 11 August 2022 - 03:53 PM
So having acquired another Borg & Beck Clutch, and now having my clutch back from MED (long story, but still not happy) I have finished building it. I wont expand here as there is another thread on it here.
One Carb Or Two?
Posted 14 August 2022 - 07:40 AM
Up Into Fourth
Posted 14 August 2022 - 10:19 AM
I've just read through your thread, very detailed, I have a question, where does the crank dampner fit on?
Shooter
The crank damper (or harmonic) is part of the crank pulley, AFIK it is a two part system with rubber in between to iron out the vibrations associated with a 1275 engine. The Crank pulley (and its damper) bolt to the radiator end of the Crank and drive the alternator and water pump. I still have this engine's original crank pulley/damper and it was balanced with the crank, however, as I am now intending to fit a supercharger, I have had to use an alloy twin belt pulley which has no damper. Ho this will affect the engine I do not know.
One Carb Or Two?
Posted 14 August 2022 - 10:45 AM
I've just read through your thread, very detailed, I have a question, where does the crank dampner fit on?
Shooter
The crank damper (or harmonic) is part of the crank pulley, AFIK it is a two part system with rubber in between to iron out the vibrations associated with a 1275 engine. The Crank pulley (and its damper) bolt to the radiator end of the Crank and drive the alternator and water pump. I still have this engine's original crank pulley/damper and it was balanced with the crank, however, as I am now intending to fit a supercharger, I have had to use an alloy twin belt pulley which has no damper. Ho this will affect the engine I do not know.
Up Into Fourth
Posted 14 August 2022 - 11:33 AM
I've just read through your thread, very detailed, I have a question, where does the crank dampner fit on?
Shooter
The crank damper (or harmonic) is part of the crank pulley, AFIK it is a two part system with rubber in between to iron out the vibrations associated with a 1275 engine. The Crank pulley (and its damper) bolt to the radiator end of the Crank and drive the alternator and water pump. I still have this engine's original crank pulley/damper and it was balanced with the crank, however, as I am now intending to fit a supercharger, I have had to use an alloy twin belt pulley which has no damper. Ho this will affect the engine I do not know.
Yup fully aware of what a crank dampner does, I'm a tad worried that you haven't got one, Spider posted an excellent piece a few days ago on this very subject personally I learned the hard way back in the 80's when I ran an pretty hot engine in my Mk1, but changed the bottom pulley for an un damped 998 one with the idea of less weight faster spin up, guess what happened the engine spat its bearings out, lesson learned and off to the library I went ( no Internet in those days) to learn about torsional vibration, I think you might be able to use a Cooper S type sold by MED and machine your blower drive pulley to fit, MED do a pulley with a trigger wheel built into the rear which would make things nice and compact, you would need to get the assembly balanced though.
Shooter
Just read Moke Spider's response you mentioned here
The pulley I am using is supplied by Vmaxscart, run by Stuart Gurr, Stuart also puts together and sells the Supercharger Kits which mine will be based on.
I have no idea why there is no damper - much cheaper to make without I guess?
I have gone around the houses several times on this subject, looking at various options. One was to change the alternator and water pump to multi vee, but I managed to pick up this pulley (unused, second hand for a great price).
I have looked at the MED pulleys but they don't do a twin belt pulley.
UPDATE
I posted the question regarding Harmonic Dampening on the Classic Mini Turbo and Supercharged FB Group. It would appear that where a twin belt pulley is employed the effect of the two opposing belts (Alternator / Supercharger), achieve the same effect as having a Harmonic Damper fitted.
"Opposing belts with acoustically dampened material works fine with no damper, up to the recommended 6500 rpm"
The fact that I fitted the trigger wheel on the outside means that it will need to be dynamically balanced (which it will be), had I fitted it to the inside, this would not have been a problem?
Edited by JonnyAlpha, 16 August 2022 - 10:32 AM.
Mini Mad
Posted 17 August 2022 - 11:04 AM
I've just read through your thread, very detailed, I have a question, where does the crank dampner fit on?
Shooter
The crank damper (or harmonic) is part of the crank pulley, AFIK it is a two part system with rubber in between to iron out the vibrations associated with a 1275 engine. The Crank pulley (and its damper) bolt to the radiator end of the Crank and drive the alternator and water pump. I still have this engine's original crank pulley/damper and it was balanced with the crank, however, as I am now intending to fit a supercharger, I have had to use an alloy twin belt pulley which has no damper. Ho this will affect the engine I do not know.
Yup fully aware of what a crank dampner does, I'm a tad worried that you haven't got one, Spider posted an excellent piece a few days ago on this very subject personally I learned the hard way back in the 80's when I ran an pretty hot engine in my Mk1, but changed the bottom pulley for an un damped 998 one with the idea of less weight faster spin up, guess what happened the engine spat its bearings out, lesson learned and off to the library I went ( no Internet in those days) to learn about torsional vibration, I think you might be able to use a Cooper S type sold by MED and machine your blower drive pulley to fit, MED do a pulley with a trigger wheel built into the rear which would make things nice and compact, you would need to get the assembly balanced though.
Shooter
Just read Moke Spider's response you mentioned here
The pulley I am using is supplied by Vmaxscart, run by Stuart Gurr, Stuart also puts together and sells the Supercharger Kits which mine will be based on.
I have no idea why there is no damper - much cheaper to make without I guess?
I have gone around the houses several times on this subject, looking at various options. One was to change the alternator and water pump to multi vee, but I managed to pick up this pulley (unused, second hand for a great price).
I have looked at the MED pulleys but they don't do a twin belt pulley.
UPDATE
I posted the question regarding Harmonic Dampening on the Classic Mini Turbo and Supercharged FB Group. It would appear that where a twin belt pulley is employed the effect of the two opposing belts (Alternator / Supercharger), achieve the same effect as having a Harmonic Damper fitted.
"Opposing belts with acoustically dampened material works fine with no damper, up to the recommended 6500 rpm"
The fact that I fitted the trigger wheel on the outside means that it will need to be dynamically balanced (which it will be), had I fitted it to the inside, this would not have been a problem?
I do not want to "pull the rug out from you" but I trust science and facts. I will do an attempt to describe it in an understandable way. Feel free to put your trust in whateer you want.
Harmonic dampers are made to dampen (=reduce movement) in torsion direction, i.e. for the crankshaft. These are supposed to be tuned inertia wise (mass and radii) to work optimal at the torsional eigenmode frequencies for the crankshaft system (crankshaft, flywheel, clutch, pulley etc.). They are usually designed with a hub and outer ring connected by a elastomer. The elastomer performs the work by its hysteresis were damping generates heat (usually not more than 15% damping in order to prevent overheating).
Damping by belts made out of elastomers do contribute but more like a broadband filter acting on all frequencies, i.e. is not tuned at all for the existing crankshaft system. (When designing an harmonic damper as a part of a new engine development, these effects are not even considered) I am fully aware of that people says it is OK to run without an harmonic damper (based on experience). This is true, since a failure will be a failure due to fatigue and not due to overload. I.e. it depends on the number of load cycles. Compare it to bending a copper wire. It works without failure, at least for 1...., 2....,3..., maybe five times. But would you say it works bending it at the same location for 25 times....!?
Believe me, i do know what you are facing. I have been down the same path myself. Axial space within the engine mount, I would say is the main issue. My conclusion was that it I could not find a way to fit the Vmax pulley (2-belt) together with a damper and a trigger wheel. I ended up in designing a hub to which I bolted a trigger wheel, a PK5 pulley and an harmonic damper. The hub is based on a pulley from MS (modified in the lathe). For the PK5 pulley I had to grind myself a lathe tool matching the PK profile and thereafter grab my manual lathe and out of an Al bar manufacture the pulley I designed. (I had to design and manufacture the rest of the PK5 pulleys as well). The outer end of this pulley matches the "Cooper S harmonic damper" from MS. So from the crank casing it is the trigger wheel bolted to the hub. From the outside it is the PK5 pulley centering and slides on the hub. The damper is centered by the pulley and bolted through the pulley to the hub, clamping the pulley. All in all, it fits into the engine mount without modifications. I believe this is one way to get around presented issue...
The hub:
https://drive.google...iew?usp=sharing
The PK5 crankshaft pulley (looking from radiator side):
https://drive.google...iew?usp=sharing
Assembled and mounted without the trigger wheel:
https://drive.google...iew?usp=sharing
Edited by Java_Green, 18 August 2022 - 12:18 PM.
Up Into Fourth
Posted 17 August 2022 - 05:43 PM
Up Into Fourth
Posted 18 August 2022 - 11:10 AM
I've just read through your thread, very detailed, I have a question, where does the crank dampner fit on?
Shooter
The crank damper (or harmonic) is part of the crank pulley, AFIK it is a two part system with rubber in between to iron out the vibrations associated with a 1275 engine. The Crank pulley (and its damper) bolt to the radiator end of the Crank and drive the alternator and water pump. I still have this engine's original crank pulley/damper and it was balanced with the crank, however, as I am now intending to fit a supercharger, I have had to use an alloy twin belt pulley which has no damper. Ho this will affect the engine I do not know.
Yup fully aware of what a crank dampner does, I'm a tad worried that you haven't got one, Spider posted an excellent piece a few days ago on this very subject personally I learned the hard way back in the 80's when I ran an pretty hot engine in my Mk1, but changed the bottom pulley for an un damped 998 one with the idea of less weight faster spin up, guess what happened the engine spat its bearings out, lesson learned and off to the library I went ( no Internet in those days) to learn about torsional vibration, I think you might be able to use a Cooper S type sold by MED and machine your blower drive pulley to fit, MED do a pulley with a trigger wheel built into the rear which would make things nice and compact, you would need to get the assembly balanced though.
Shooter
Just read Moke Spider's response you mentioned here
The pulley I am using is supplied by Vmaxscart, run by Stuart Gurr, Stuart also puts together and sells the Supercharger Kits which mine will be based on.
I have no idea why there is no damper - much cheaper to make without I guess?
I have gone around the houses several times on this subject, looking at various options. One was to change the alternator and water pump to multi vee, but I managed to pick up this pulley (unused, second hand for a great price).
I have looked at the MED pulleys but they don't do a twin belt pulley.
UPDATE
I posted the question regarding Harmonic Dampening on the Classic Mini Turbo and Supercharged FB Group. It would appear that where a twin belt pulley is employed the effect of the two opposing belts (Alternator / Supercharger), achieve the same effect as having a Harmonic Damper fitted.
"Opposing belts with acoustically dampened material works fine with no damper, up to the recommended 6500 rpm"
The fact that I fitted the trigger wheel on the outside means that it will need to be dynamically balanced (which it will be), had I fitted it to the inside, this would not have been a problem?
I do not want to "pull the rug out from you" but I trust science and facts. I will do an attempt to describe it in an understandable way. Feel free to put your trust in whateer you want.
Harmonic dampers are made to dampen (=reduce movement) in torsion direction, i.e. for the crankshaft. These are supposed to be tuned inertia wise (mass and radii) to work optimal at the torsional eigenmode frequencies for the crankshaft system (crankshaft, flywheel, clutch, pulley etc.). They are usually designed with a hub and outer ring connected by a elastomer. The elastomer performs the work by its hysteresis were damping generates heat (usually not more than 15% damping in order to prevent overheating).
Damping by belts made out of elastomers do contribute but more like a broadband filter acting on all frequencies, i.e. is not tuned at all for the existing crankshaft system. (When designing an harmonic damper as a part of a new engine development, these effects are not even considered) I am fully aware of that people says it is OK to run without an harmonic damper (based on experience). This is true, since a failure will be a failure due to fatigue and not due to overload. I.e. it depends on the number of load cycles. Compare it to bending a copper wire. It works without failure, at least for 1...., 2....,3..., maybe five times. But would you say it works bending it at the same location for 25 times....!?
Believe me, i do know what you are facing. I have been down the same path myself. Axial space within the engine mount, I would say is the main issue. My conclusion was that it I could not find a way to fit the Vmax pulley (2-belt) together with a damper and a trigger wheel. I ended up in designing a hub to which I bolted a trigger wheel, a PK5 pulley and an harmonic damper. The hub is based on a pulley from MS (modified in the lathe). For the PK5 pulley I had to grind myself a lathe tool matching the PK profile and thereafter grab my manual lathe and out of an Al bar manufacture the pulley I designed. (I had to design and manufacture the rest of the PK5 pulleys as well). The outer end of this pulley matches the "Cooper S harmonic damper" from MS. So from the crank casing it is the trigger wheel bolted to the hub. From the outside it is the PK5 pulley centering and slides on the hub. The damper is centered by the pulley and bolted through the pulley to the hub, clamping the pulley. All in all, it fits into the engine mount without modifications. I believe this is one way to get around presented issue...
I too believe in science 
Do you happen to have a picture of the hub you made, sounds like an awesome project, but I neither have the tools or the skills to make one? But yes the true answer is put together a single v pulley, a multi vee pulley and a trigger wheel onto a damper.
Mini Mad
Posted 18 August 2022 - 06:36 PM
Up Into Fourth
Posted 18 August 2022 - 06:46 PM
I hope the links work....
..sorry; couldn't resist 
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