Manky Monkey Motors

Looking for knowledge relating to Superchargers/Teflon/Methanol.

Aisin make a couple of small superchargers for the Japanese market, namely the AMR300 and AMR500 (300cc & 500cc volumes respectively) which run a twin-rotor setup.
The rotors on units I’ve physically seen, and seen for sale on the web have Teflon/PTFE coated rotors.

A friend thinks he heard it said that the ‘early’ units didn’t have the coating.
Anyone here aware if that’s the case?

Reason for asking I’m involved in a project where the owner would like to run on methanol instead of ordinary petrol, and the methanol/Teflon combination isn’t good, so an option is to strip the Teflon.
The Teflon seems fairly thick on a unit I saw where part of the Teflon was lifting - anyone know how thick the coating actually is??  ???

An alternative option is to find a Shorrocks blower (C75 / C75B), at an affordable price – anyone out there have one lurking about the place looking for a new home?   ::)

The fall back position would be to use the Mini Cooper or Mercedes Eaton blowers that are all over e-bay (and remove the Teflon etc), but at present he’d like to keep with the idea of the Aisin or Shorrock set-up.

Cheers All.

Saw a bunch of Aisin ones (used) at Beaulieu last month, all at about £350.
Or this .......
http://www.ebay.co.uk/itm/VINTAGE-SHORROCK-SUPERCHARGER-C75B-FORD-CORTINA-ANGLIA-MORRIS-MINOR-VW-MG-/370819092257?pt=Vintage_Car_Truck_Parts_Accessories&hash=item56568a4f21

Thanks Phunkie,

Looks like a visit to a big car jumble might be on the cards. The £350 price seems to be the going asking rate, but a used Aisin 500 can be bought from Japan for around US$300 (£186) incl shipping (plus what customs add), but details of item for sale just says "perfect working order", mmmm.
The Shorrocks has been on ebay for a while, think the price, plus shipping, customs charges and then re-furb kinda put it out of reach.

Best mate has told me: “The Aisin blower coating is a Teflon based plastic paint stuff which enables the rotors to be run almost in contact. If they touch then Teflon v Teflon wears to a very close tolerance. I have read that this increases the efficiency of the rotors by a meagre 5%. and assists in making the blower quiet as less air can whistle past the rotor tips.
Removing the Teflon will reduce efficiency by approx 5% but as I assume a suck through setup is proposed efficiency is improved by 15% by virtue of the wet charge. No pain no gain!!"

The proposal to run methanol is now being re-considered with the idea of running petrol (poss 100 octane / avgas/super-unleaded or similar) taking its place, which would make the methanol/Teflon issues superfluous.
Always best to get the ideas sorted before the build........ :-\

Hi Tony.
All the Teflon coated rotors are from blowers that are designed to compress air not air fuel mixture. I have read some horror stories of ethanol in petrol dissolving/flaking the Teflon when utilised as a suck through system. Whatever fuel you use either get an earlier version which was uncoated or have the coating removed. For the application you are aiming at a few more blower revs will overcome the losses. Most of these modern blowers run between 14 and 18 thousand rpm constant. They are also low pressure blowers with bypass valves for the lower rev range (for emmisions) so with the bypass blocked, suck through setup giving more 'grip' to the rotors and revs up a bit the jobs a goodun.
I would remove the teflon from any charger I was using as a suck through system.
But then I am a bit sad and anal about these things ;)

Remember the blower Loony had that you looked at Andy? We're planning on using it on the Reliant powered T bucket project, (more to be able to say it's got a supercharger than for added power to be honest). How would we remove the damaged Teflon coating from the rotors?

Hi Andy,Nice to see you back. I went to Toronto some years back and loved the place.
The Eaton M45. It is a total pain in the rectum. You dismantle the blower so you have the helical vanes separated. I have done this as I needed to reverse the drive. The fun bit is reassembly but I will come to that. I fine glass bead blasted the vanes (low pressure so as not to remove any metal) took me about 4 hours per helix. The Teflon stuff is like a plastic coating and the glass beads bounce off of it until it manages to key the surface and gets a hold. In retrospect I could have tried chemical removal as this may be done without as much dismantling. I did not realise how bad the coating was coming adrift until I dismantled it. The visible area in the helix looked OK but either end was flaking. This was not visible in situ.
Once you have the end cover off and the inner bearing/seal housing out this will expose the vanes. If the blower is an M45 from a Mini you have to pull the water pump gear from the rear housing from the other end of the drive vane. The fun part comes when you reassemble as the gears are pressed on and off but are not keyed. The vane tips pass at about 2 thou so you have to time the gearing exactly spot perfik.
Upon dismantling I would mark the gears to each other and mark the shaft ends to give you an idea of where they should be and press them back on together whilst ensuring the vane tips are in exactly the right spacing. I have reversed the drive on mine and have yet to attempt re assembly of the gears as they will be fitted on the opposing rotor and the drive nose is turned through 180 degrees, and as the drive nose is not symmetrical this has been re-engineered too but I doubt if you need worry about that.
I am told the Eaton works fine in either direction (Inlet becomes exhaust if reverse driven) but I do not have the space on my project for such luxury so I have no option but to reverse the drive and the gearing to suck through the inlet and blow out the exhaust on the opposite side of the vehicle than it was designed for.
The bearings and particularly the seals are special. The bearings are high speed rollers with double opposed lipped, metal rimmed seals on the drive end and the inlet end has 2 needle rollers with integral seals packed with some sort of special blue grease. My needle rollers were fine but I have changed the bearings in the drive end. 4 ball races and 3 seals. I have had to compromise on the seals as Eaton don't supply them outside of a factory exchange rebuild. I have used seals compatible with methanol and maybe a splash of nitro but the seal housings were modified to accept them. The drive train oil is special stuff too and bloody expensive as it has to cope with 14-18000 rpm, varying temperatures and be compatible with the varied materials in the drive and coupling device and not froth but as mine will only be doing 1/4 mile at a time I will only use it once, hopefully!! I hope it works. If it doesn't it will have been a useful exercise in finding my engineering limit.
Hope that helps. A bit long winded but you did ask and I have a tendency to rattle on a bit ;D
To answer Tony. The Teflon is under 2 thou but varies as it covers up the imperfections in the vanes which are drawn through a die and apart from the ends are unmachined.

I wish I hadn't asked now!  :P

 ::) but you did

 ;D

Mr Dslam - he be the blower guru then  :D

Ta for info matey

Carb'd or injection?

carb'd. probably an SU or such like

If you used a Metro turbo carb (SU) it could be put downstream of the blower. Could do the same with port injection. Presumably this is a race machine? Mechanical Injection?

I am building a Triumph pre unit 750 sprint/drag bike. I have had a hankering to build my own frame and do all the fabrication myself for many years. Two reasons for this,

1: I am a skint tight ar*e.

2: Because I think I can.

I want to run a suck through system because anything else, in my eyes at least, does not look right on an 'old school' style bike. I thought about Old look/modern kit but there is nothing like a blown Triumph. I plumbed for the Eaton blower because of the price (see item 1) and Shorrocks blowers and the like are getting hard to come by and ridiculously expensive (item 1 again) and even dearer to rebuild.
I did consider the MG Metro Turbo carb/blow through. I have one 'in stock' but it is a pig ugly bit of kit and I am a firm believer in if it looks right it probably is. If I was building something where the engine was out of sight then I would run blow through as it is easier with the right carb.
The injection idea is a good one too but all that electrikery on a Triumph. Not good and it's probably too technical for me as I am stuck in the dark ages anyway  ;D
I think Tony's original question at the start of the thread referred to a similar project he has in mind and an Austin 7 his mate is building. Perhaps I can find a home for the turbo carb with him. Hmmm

Injection wise, I didn't mean electronic, I meant mechanical like back in the day (like a Hilborn set up). You have to do quite a bit of modifying to a SU to run alky (was connected with the Stripteaser team back whenever, when they started "tampering" with alky). Just need a pump, barrel valve and a couple of injectors.   ;)

I have a base setup with an SU already. It should need just a tweak to setup for this motor.
Thanks for the input though it is easy to get tunnel vision over this stuff so keep the ideas coming.
I had the germ of an idea some years ago and I have planned it all out in my head and some of it is now in metal. The manifild and plenum are part constructed as is the carb manifold for the blower so I am on the way.
Maybe the next one I will consider injection. A bit of research is in order me thinks.

You could run a couple of  injectors into the plenum, rather than directly into the ports.
 How are you going to move enough fuel (assuming here that you're running alky) through the SU?
 On Stripteaser (normally aspirated) 3 x 2" SUs on a Jaguar 3.8, rotary electric fuel pump (Holley or some such), no needle valves (just the fuel coming in in the normal location and a return from the side of each float bowl at the point that would be the normal fuel level.

2 large bore taps gravity fed into an adapter which replaces the float bowl. This feeds directly into the carb body. It runs a flow rate of 4 liters in 10 seconds which should be ample. The needle regulates the flow as normal but is modified for methanol. If I decide to up the game a bit and add some Nitro then a needle change is all that is required. This engine has run methanol with a Shorrocks C75 on this basis and used 3 liters per run. It's only a Triumph twin after all ::). The needle has an O ring on it which stops/reduces the fuel flow when the throttle is shut. The carb runs in a permanent state of near flood but when setup right it shouldn't leak. All pretty standard fare for the period really. The only real change is the type of blower being used and the way in which the mixture is delivered by it. As for injection I refer the honerable gentleman to the answer I gave some moments ago ;D

I have an Aisin 300, purchased from Japan.. sneaked through custom's somehow so didn't pay any duty.. it is in excellent condition and looks to be hardly used.. oh and it arrived 5 day's after purchase  ;D

Hi Shaun,

Are you going to be running it as a "suck through" (ie fuel as well as air through the chamber)?
If so, what fuel? (pump gas, AvGas, methanol)

Guessing as its a 300, this is for the Panther?  ::) Cool......

Be interested to know if you're planning to strip the rotor covering....................

I haven't got that far yet Tony.. saw it at the right price and thought thats got to go on the shelf...