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MG Midget and Sprite Technical - Toyota 5 speed - clearance & clutch issues

Hello,

Thanks for everyones help with the issues I have had so far.

I've tried to do a test fit tonight of the engine (1275) and my new toyota 5 speed setup so that I can work out what I need to modify and how to setup the gearbox mounts. I know a number of people here are using this conversion, so hopefully someone can help me - It seems to me that the engine and gearbox cannot be fitted with the front panels in place. When I tried to put the engine and box in I couldn't get the rear of the gearbox high enough to go in the tunnel. The rear of the box wasn't high enough, the middle of the box was hitting the heater tray, and the front of the engine was fouling on the radiator support. Surely everyone who uses this box doesnt have to remove the entire front end every time they fit and remove the engine and box? I did wonder if perhaps the shroud that surrounds the rear spline to connect to the tailshaft can be removed, as I suspect that without this it would be able to fit.

Also, the clutch plate that came with the conversion is 7 inches across, the one that was in the car is smaller and the clutch won't fit the larger plate. Apparently the new plate is meant to fit a stock midget clutch. Anyone know what the story is here? For anyone wondering, I did the trial fit above without a clutch fitted at all.

Thanks in advance for your help, it's much appreciated.
AndrewF

Hi Andrew,
I have a 1430/Toyota set up which is out of my Frogeye at present.The centreplate is 6.5". I think it's a 1275 outer with a Toyota splined inner. i.e. a special made up by AP Racing.
The Cover ia a 6.5" Diaphram type, it may well be standard 1275.
I am sure someone over here will be able to give you chapter and verse on the set up/sizes etc.

On the subject of getting the box into the transmission tunnel you will probably have to cut back the 'floor' of the tunnel (Depending on the type of body you have). This will allow you to get the front of the engine down over the chassis cross member without knocking six bells out of the heater/battery tray, so, you can then raise the rear of the box up into position.
First measure the overall length of the engine and box together, then measure and mark up the chassis, adding say an inch, to give you enough clearance to fit the full assembly without fouling the front crossmember/rear floor area.
You will then need to cut the floor out, BUT, before you do you must work out FIRST how you want to refit a new floor panel to retain rigidity. Cut out the absolute minimum you need. My engine/box was very tight coming out so I am in a similar position to yourself. I intend making up a removable panel,firstly to retain rigidity in the structure, and, secondly to make life easier next time round.

As an aside, whilst you have the engine/box still on the floor, measure up the clutch slave cylinder position and try to make a stab at where it comes in relation to the RHS chassis rail. Keep the slave cylinder in mind when you are setting up the rear gearbox mountings as my slave set up is quite close.

Peter
PJ HOBSON

Andrew
I didn't want to cut the floor pan in the interests of rigidity (and maybe wanting to return original gearbox) and so I cut out the battery tray and then made it removable, by bolting it back in with 3mm screws and captive nuts on the body. Either way you do have to cut the chassis somewhere. But you shouldn't have to remove the front panels, although removing the front panel doesnt take that long, as you generally already have the radiator out, unless the attachments are corroded !

Here in the UK most people use an AP Racing driven plate that accomodates the Toyo box with the original diaphram type clutch cover. APR will still supply this plate, I purchased 2 last year, cost is £40 to 50 GBP each. I can let you know the part number if required.

Ian



Ian Webb '73 GAN5

Ian,
Can you give me the p.no as well please. I might as well get a spare.
Peter
PJ HOBSON

I too have the Toyota gearbox conversion, did it some 15 to 20 years ago. As Peter says the chassis rail has to be eased out to accomodate the slave cylinder. and I only cut the cross member and strengthened it in the manner described on here numerous times.
I always remove the engine singularly to avoid the problems you are encountering and find it very easy. Although the gearbox is pushed hard up against the heater box/battery tray when lining up the 2 and getting over the rack.

I use the same clutch arrangement as Ian and peter but I am not happy with the standard Midget prssure plate as my clutch will not stand up to the power I want to give it so I am looking for an upgade. I therefore wonder what your clutch is

Here is the information for the clutch plate as supplied to me by another member of this BBS


The AP Racing ref is CP2323-11. It was, may still be, a 'standard' for them.

I got mine from Raceparts (UK) Ltd, in Wallingford, Oxfordshire 8 years ago, so don't know if they still have or can get one.

Their telephone no. is 01491 822000.

Please let me know if you get one from them, I think it would a good idea to get a spare in!

Price then was c£40.

The 'original' suppliers were Minor Mania, in Mill Hill, tel. 020 8959 0818. No mention on their website now of the Toyota kit.
Robert (Bob) Midget Turbo

Bob,
I have a note to say the driven plate is CP2323-11.

My engine is a 1430/Oselli, was A286 Megadyne but going to fit SW5-07.

All clutch bits are in a drawer behind my other motor in garage, which is currently in a plastic bag, trying to avoid the Pennine Damp (attacking Italian 'steel' and electrics!)

Will get back to you on cover details etc.

Had no problem with clutch slip etc, previous owner says he had 90+ brake on rollers. What power/torque are you looking at?
Peter
PJ HOBSON

Hi Andrew,
Dellow in Revesby NSW had some 6.5" plates about 18 months ago (6.5" 2T/3T to A series) but the price was more than the $80 (equiv) mentioned for the AP item. Colin Dodds at Dural might well give you a steer. The gearbox mounting, if needed, is still available from Toyota, part no. 12371-33010. The parts person will ask for the car identity to get into the lists - I found model no. TE72 or KE70 (79-84 Corolla) worked fine.
Hope that helps.
Derek
Derek Stewart

Bob, I have been discussing with different people here who have done the conversion. The clutch plate I was sent was the wrong one and should have been as the rest of you describe. However I am looking to supercharge my engine, so have been recomended a different setup that has reportedly been used by others here - a Hillman Hunter clutch setup with Toyota Tercel plate. This gives a 7.5" clutch that has been used in race cars with 170hp and big slicks without issue.

As for everyone else, thanks for the help. Someone from the MG Car Club I am a member of who has done the conversion before has templates for everything and the pieces of metal they cut out and they are going to lend them to me so this should make life easier. It was recommended that I do remove all the front panels (guards and radiator support) for the first fitment, but that following that it shouldn't be required. Unfortunately after removing the drivers guard late last night (including a rivet that some DPO had used to attach the front chrome trims that went through the guard and another panel) I didn't take enough care when placing the guard back on the car, and it fell on the concrete and tools below, scraping off a lot of paint and putting a dent above the headlight. I am not happy, still kicking myself over that. I had planned to respray the car, but as the engine now requires a rebuild, that has been put off until some point in the future.
AndrewF

Thanks Derek, I had started writing the previous post last night before going to bed, so hadn't read your comment. Colin Dodds has indeed been a big help, and was the one who recommended the Hillman Hunter clutch setup.

Thanks,

Andrew.
AndrewF

To answer an earlier post by Peter I had my car on the rollers a fair time ago when I had first converted it to a turbo. With the standard dump actuator giving about 6 or 7 psi of boost and standard ignition I got about 113BHP at the flywheel. The standard midget pressure plate with the AP friction plate managed this power fine.

Since that time I have been able to improve the ignition set up with a programmable system and also the waste gate actuator is now an after market item which is giving me 23 PSI of boost. The power is now enormous by comparison. Unfortunately something has to give and it is the clutch, so I missed the opportunity to attend the MG Car Club rolling road session to find out my true potential now. However there will be opportunities next year for sure if I can find an answer to the clutch problem

In the mean time I need to investigate trying to fit a Peter May clutch or the Hillman Hunter mentioned by Andrew. Have you got more info Andrew or when you have fitted it can you let me know the pitfalls?
rjwelchmidgetataol.com

Robert (Bob) Midget Turbo

Andrew,

Centre plate - CP2323-11 - is still availbe from Raceparts - they got me one earlier this year. I had 112 bhp from our 1380 at the same session as Bob, no turbo, and likewise have had no problems with clutch slip. I only bought the new plate as a precaution when rebuilding the engine earlier this year. The original plate had cover 30,000+ miles and was at most 50% worn. I have kept it as a spare!

I have scans of the original fitting instructions from Minor Mania that include the mods to the Sprite/Midget crossmember. If you can give me your email address I will send them to you.

Somewhere I have details of an AP Racing centre plate that is 7.5" o/d and has the Toyota spline - will look for it and post the part number. If a standard Tercel plate is the same size, might be a simpler solution?

I have recently acquired a complete Metro Turbo set-up to fit maybe this winter, so possibly the 7.5" clutch would be a good idea at the same time?

Richard
Richard Wale

In answer to all you 6.5" guys (Hmmm), I spoke to AP yesterday and ordered a 6.5" centreplate from my local agent, on P.no. CP2323-11. Availability will be approx 4 weeks as they make to order, so, they are available. (N.B. 21 splines)

Bob, the new centreplate thickness is circa 0.285", 7.24mm if you've been metricated!

My cover is stamped QY13001, my AP contact said the number did not mean anything to him and the tech. reps were in a meeting so no joy until monday.
My cover has 18 diaphram 'fingers', one stamped KC2210 and one C222. A steel ring is located, loosely, on the 'fingers' which is the contact point for the Toyota sealed thrust bearing to actuate the diaphram. This info may help you determine if your clamping load set up was similar to mine.

It looks as though you are all going in the direction of 7.5" plates and lots more power whilst I am dropping HP for an easier life with more bottom end torque.

Also thanks Derek for rear mounting info, always useful to know.

Andrew, keep us up to date on what set up you finalize on.

Peter
PJ HOBSON

Richard, I have recieved fitting instructions from a member of the car club here who has done it before, but another copy would always be welcome, if it's a different option then I may prefer it. My email is andrew*dot*fraser*at*transgrid*dot*com*dot*au

Bob, the Hillman Hunter clutch is a popular upgrade over here with standard gearboxes, however there were only a couple of manufacturers who made units that fit (with a small amount of modification) to the standard rib case bellhousing, and they have now been discontinued. I can get one, but at an increased price due to them being NLA. However, looking at the Dellows Toyota bellhousing compared to the standard one it appears that there is a fair bit more space in the critical areas for the clutch, so I am going to see if a different Hillman Hunter clutch will fit. I'm told the issue was that most manufacturers make them with 3 mounting bolts and the two manufacturers that were used in spridget upgrades used 6 mounting bolts. The ones with 3 mounting bolts are thicker to gain the rigidity required, and so require more clearance. The two people who told me about fitting the Hillman Hunter clutch with a Toyota Tercel plate with a Toyota 5 speed box didn't mention that a specific brand of clutch was required, however it could have just slipped their memory. They did mention a bit of grinding of the bellhousing. Of course the flywheel must be machined and redrilled to suit. The Hillman Hunter uses a carbon release bearing like the spridget and so a stock carbon release or replacement roller release bearing can be used.

I have been advised that the 6.5" clutch starts to become an issue at ~120bhp. I am hoping for more than that, I will be looking at ~15psi from my Toyota blower on a suitably rebuilt and cammed motor.

Actually (and maybe this requires a new thread) does anyone know the limits of an HIF44? My setup will be suckthrough using water injection to cool the intake charge and control detonation (I have good experience with water injection on turbocharged rotaries), and I'm wondering if I really need to go to a 2 inch SU instead over the HIF44?
AndrewF

Welcome back Richard. The 7.5 inch plate sound like just what I am looking for, I suggest you might like to consider this also.

My clutch begins slipping when I give it some pill0ck at about 80 to 90 MPH. I think at this speed the power from the engine is needed and I think I am giving it about 140BHP at that point so perhaps a standard midget clutch is only good for about 120?

I must get this sorted as I want to see what the engine is producing now before I do further mods. It must be more than 140BHP otherwise I will be disappointed. Don't tel our mate Mr Strange cos at the moment my cylinder head is not ported and is standard want a rolling road read as the engine is at this moment so I can see and measure the improvement I will get from porting the head. I think I will entrust that to Peter B.

Also Richard did you tell me that a tailor made bellhousing is available for the standard Midget backplate to toyota box? if so where can I get one from. Would really love to get rid of my extremely heavy adapter plate.
Robert (Bob) Midget Turbo

Andrew you might find it easier and cheaper to get a clutch done by 'Race Clutch' at Stones Corner in Brisbane.
I have a Celica box and Dellow kit on the bench waiting its turn to go into my wife's Midget. Dellow get the gearbox mounts made in India for a fraction of the price of the genuine part and it needs no mods to fit the Spridget.
Mike Allen

Andrew,

T50 instructions on their way to you.

Bob,

<Welcome back Richard> ?? Wasn't aware I'd been anywhere!

Have looked for the clutch details and found the cover plate and roller release bearing, but not the driven plate, yet!

The bell housing was part of the Minor Mania kit (ex-Rooster Racing in Australia), but I haven't seen one anywhere for a very long time. It does exactly as you say, allows the T50 to bolt up to the standard 1275 backplate and uses the standard BMC release fork, mounted in a special bracket inside the bell housing.

Sorry I can't be more help.

Richard
Richard Wale

Andrew

Which Toyota box are you using?
One of our Midgets has A series with Toyota conversion, it has retained the chassis crossmember under the gearbox mounts and it is a tight fit ... we can just sneak it over the fornt assy's shut panel if we remove the crank pulley. A bit of a bugger, but lots less work than removing the whole front!
Paul Walbran

I am using a bellhousing that is made by Dellows in Australia, it bolts the T50 up to the standard 1275 backplate and uses the BMC clutch release fork and starter etc, as described by Richard above.

Mike, I have the Dellows kit and this doesn't bolt directly into the car. The gearbox mount they provide is just an aftermarket manufacture of the standard Toyota rubber mount. Cutting of the car appears definitely required, as is manufacturing an area for the gearbox mount to bolt to. The Dellows kit provides everything to bolt the gearbox to the engine, but not to get it into the car. Sorry if I misunderstood your post.

Richard, thanks for the email, I haven't had time for more than a quick glance yet, but it looks quite different to the other method I've been given.
AndrewF

Paul, that's interesting, it is the the T50 gearbox. I think there is one smaller Toyota gearbox (K series?) that fits without cutting, but I don't think the T50 will? If I can be shown otherwise then that would be great! The method I have been given for mounting the box does require cutting the crossmember but involves another welded brace to restrengthen the shell.
AndrewF

Our one is using the smaller box I think - it is ex-Starlet, being only semi Toyota-literate that's all I know. It's a polular conversion here due to not needing to modify the chassis and the abundance of dead RWD Starlets.

I have heard that the T50 does require chassis mods incl removal of crossmember.

With two of our other Midgets (the K ones) we have fitted a Supra W57 or W58 box (can't remember which, it's only top gear ratio which is different as I recall) but both these require tunnel mods which I have outlined on my website at http://www.mgparts.co.nz/bogs_car.html
Paul Walbran

Paul, I don't believe we recieved the RWD Toyota Starlet here, that is the smaller box I was thinking of. I don't know whether or not there is another source for those boxes in Australia. As for the W Series boxes, I have one of those behind the V8 in my VH Commodore daily driver. Nice boxes, but looking at your website they definitely require more modification than fitting the T50 does. I love your work by the way, I can certainly appreciate the fabrication involved.
AndrewF

This thread was discussed between 25/11/2009 and 01/12/2009

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.