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MG MGA - CLUTCH WEAK
|I am going to pull my engine to repair a leaky rear seal and at that time I want to replace the clutch plate. When my foot "accidentally puts the pedal to the metal" the clutch does not grab and hold. My engine does produce power 18v with a Judson supercharger. What and were do I get a clutch that can hold up to the power of the engine and not slip. All hydraulics are in great shape.|
Long Beach, California USA
|Jeff, for you in the US I'd have a look and see what David at Aptfast has to offer--|
|If You have an MGB-gearbox with fine splines, the whole Ford Pinto/Escort range will fit. Look at Burton Power(GB)|
|Dirk Van Ussel|
|If you go to the MGAEXP forum, look up Basil Adams. He races MGAs and sells lots of parts. He would probably be able to recommend and supply something. Hap Waldrop builds race engines; he would be useful as well. |
I suppose it's possible that your clutch slip might be due to oil leaking from your rear seal too.
|Switch to a standard MGB clutch assembly and fork. I gave up on MGA clutch assemblies years ago. You need the MGB gearbox front cover and fork and the flywheel needs modifying for the MGB pressure plate pin pattern, but that's all and then the clutch will be almost digital in the bite (or should that then be byte?) as with a lightened flywheel it's always either in or out and there is almost no pedal travel in between.|
The transmission is a Ford Sierra from Hi Gear. The front of the transmission has been changed to a MGB with a MGB clutch fork. The car has an early MGB flywheel that is smaller and lightened. I will have to check with ADP racing in California which is near me. I do not know if Beck/Arnley is a good tight unit or some other brand.
a heavy duty MGB clutch should cope well with your engines power.
I have a 140 bhp 1950cc 18V engine also with a Ford T9 gearbox and the h/d clutch operates and feels just like a standard one.
You can burn a clutch out by excessively slipping it but unless your engines cam gives no low down power and you have to slip the clutch a lot to pull away, then it is not a very likely cause.
(Superchargers are all about low down torque)
Most likely it is oil contamination but, in the end, you won't really know until the engine comes out.
|I agree with Dominic and Colyn. My coupe 1950 cc cross flow head etc runs mgb clutch with 4 syncro overdrive box. No problem with unwanted clutch slip - regular hillclimb competitor 4000 rpm take offs. |
question, but what boost pressure and horsepower do you estimate you are putting out--well I mean your engine really
Just out of interest
|...or in top gear with at low speed with full noise that is more relevant. Jeff have you tried taking off in 4th with hand brake hard on - can you get to slip then?|
|My MGA has a boost of 4.5 to 5. It is not too much but enough to give it great torque and hopefully will not blow a head gasket. As to what horse power it has, I have not put it onto a dnyometer to see what the output is. I have not tried to start in 4th with brake on but can take off in 2nd with no problem. Time for me to take engine out and replace rear seal. |
What is the best way to remove seal and what tools to use. It has a spedi sleeve in about 4k ago. Should I leave the spedi seal in and just replace the rear main seal?
Thanks for the boost pressure info
As far as the speedy sleeve goes, it must have been fitted for a reason (worn shaft) so if it's ok I'd be leaving it there and just flick the seal out and replace it
BUT- if it's oil on the clutch making it slip it is more likely to be coming from the gearbox seal
You need to have a good look in there when you get it apart
Actually if you are going to all the trouble of pulling the engine, the small extra cost of replacing both engine and gearbox seals would be a good move
|Ditto on the early MGB clutch as Dominic described. I used an early MGB flywheel instead of drilling the MGA plate. I believe Barney has description of this swap on his site.|
|I have had crank seal leak but it has never effected clutch. Flywheel and centrifugal force keeps oil away from clutch. I use the Moss uprated seal which comes with a neat plastic guide for sliding the back plate with seal on to crankshaft. You will see if speedi sleeve is worn when you open up - very unlikely. Did you put a sealer on the speedsleeve id when fitting originally eg locktite thread locker?|
Testing clutch with lower gear reduces load on clutch. Test in top gear puts maximum load on clutch.
Agree with Willie if oil is culprit it is most likely coming from gearbox.
There has been several issues with getting the right clutch arm, thrust bearing, clutch cover combination with this conversion here in Oz so you may have an issue with geometry.
|I had a serious rear main seal leak once and it definitely affected the clutch. That was the impetus for me to conjure up and install the rubber rear seal.|
|Mike Ellesmore (photo above) you got off the line without "clutch slip" -- sorry to say Steve Gyles had trouble with his as he tackled the same Rob Roy Hillclimb in 2010!|
He left no rubber!
|Barry no wonder Steve didn't leave any rubber he was in 4WD!|
Barney - if leaking rear seals cause clutch slip most MGAs around here would have a problem (wink)
I've spent a lot of time studying the two pics and sadly we will have to disqualify Mike for jumping the start so the race goes to Steve- but he as well will have to be careful with his finger being very close to being over the line
|I had only made a few yards when the green light came on before the kangeroos left me for dead.|
For anyone Brits going to Melbourne this hill climb is well worth a visit. What a facility for the local MG club.
It always amused me that the word 'START' is facing in the wrong direction.
FWIW I use the MGB assembly in my 1800 Type 9 combo. I have had only one issue in 17 years and that was a worn bush in the operating arm causing the thrust bearing to run off centre. I changed the friction plate while I was sorting it out because it was convenient to do so rather than any significant wear. Other than that no problems, far superior than the MGA assembly.
This thread was discussed between 21/02/2017 and 28/02/2017
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