Opinions on this clutch wear

[Moseley]

Evening folks, so towards the end of last summer, I started to notice a smell like burning brakes or clutch that tended to only happen at motorway speeds after climbing a hill. At the time, I presumed that the clutch was slipping, however, I haven't noticed anything unusual regarding revs increasing out of sync with road speed rising when giving it some beans.

I've just gotten around to pulling the engine, hoping to see some obvious signs of clutch slippage, but now I'm not overly convinced. Engine is an 1835 running about 80hp and 115ftlb torque. Gearbox is a 091 rancho freeway flyer. Clutch is a standard 200mm 'late bay' Sachs clutch. Here are some pictures of the clutch and flywheel, which has done no more than 10000 miles.

To me, there appears to be a bit of bluing on the flywheel, but nothing particularly excessive. Also, the friction plate looks to still have a reasonable amount of life left in it, but maybe looks a bit more worn and glazed than I'd expect considering the mileage. I could just chuck in a stage 1 clutch, but I guess I'm not convinced that the standard clutch is actually slipping due to the power - looking at figures online, the clutch should be able to take a reasonable amount more than the bus is running.

Thoughts - anyone who has more experience with clutches than I do?!




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[Moseley]

Ok, so the more threads I read, the more I'm thinking that the clamping force isn't man enough. It seems there have been others running similar power who are getting full on slip with the same clutch, so I guess it is Kennedy stage 1 time...


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[K@rlos]

Stick a stage 1 on it with a stock friction plate, that should be ample. I’ve got stage 1 sitting in my workshop, only got couple 100 miles on it if you want 1, dynamically balanced too. I had to upgrade to stage 2 because I had the same issue with my stroker motor.

 

[K@rlos]

Or if you wanna stay with the stock clutch work out the break away torque, you have the output figures for the engine. Will tell you if the stock clutch is man enough

 

[Moseley]

Stick a stage 1 on it with a stock friction plate, that should be ample. I’ve got stage 1 sitting in my workshop, only got couple 100 miles on it if you want 1, dynamically balanced too. I had to upgrade to stage 2 because I had the same issue with my stroker motor.

When you say it was dynamically balanced, was that with the flywheel and crankshaft attached? How much would you be looking for posted - pm if you’d prefer.


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[cunning plan]

Engine is an 1835 running about 80hp and 115ftlb torque.

Just a side note, is that 80hp at the wheels? I would have expected more from a 1835cc? oke:

 

[Moseley]

Engine is an 1835 running about 80hp and 115ftlb torque.

Just a side note, is that 80hp at the wheels? I would have expected more from a 1835cc? oke:

Yes I'll be honest, I thought the same! The engine was built in the States, and then shipped over to the uk by the previous owner of the bus. The RR was completed by the builder, so one would assume it was bench tested. Once I've swapped out the Empi carbs for some proper Webers, I'm planning on getting it set up on a RR, so maybe will see some better figures.

Alternatively, maybe the original figure is low because the engine was newly built - might explain why it has loosened up and is now making enough power to make the clutch start to slip...?


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[cunning plan]

Duplicate post, see below!

 

[cunning plan]

Yes I'll be honest, I thought the same! The engine was built in the States, and then shipped over to the uk by the previous owner of the bus. The RR was completed by the builder, so one would assume it was bench tested. Once I've swapped out the Empi carbs for some proper Webers, I'm planning on getting it set up on a RR, so maybe will see some better figures.

Yes, it could be a badly setup engine or cheap poor flowing carbs, hopefully!

Has it got electronic Ignition? 123 Distributor?

Alternatively, maybe the original figure is low because the engine was newly built - might explain why it has loosened up and is now making enough power to make the clutch start to slip...?

I would hope so and makes logical sense. Although, I have always planned to build a nice 1776cc as in my mind it is a good compromise of an engine, however if 1835 is only worth 80bhp, I will have to reconsider and look at a Subaru engine or V8 or something :lol:

 

[K@rlos]

Depends on the spec. If it’s got 80hp at the wheels with stock heads, minimal porting and a very mild cam then that’s pretty good, will be 100ish at flywheel. If it’s got big carbs, fancy big valve heads, lots of head work and a cam like an Engle w130 then yeah that’s pretty ****. All depends on who built it and spec.The JPM 1776 made 240hp, I know people who’ve had 2276 strokers built that haven’t made 130hp.

Subaru engines belong in Subaru’s in my opinion :lol:

 

[Moseley]

Engines and various upgrades are a new one on me, all my time has been concentrated on other parts of the bus, so taking it out for the first time is giving me a good chance to understand and learn about it all. I'll let you be the judges of the spec as some is a bit meaningless to me just now:

1835, mag case, forged counterweighted crankshaft.
40x35 heads
100 size cams
AA 92mm thick wall pistons and cylinders
HD oil pump
Compufire electronic ignition
009 dizzy
Empi ICT34 copy carbs


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[K@rlos]

Engines and various upgrades are a new one on me, all my time has been concentrated on other parts of the bus, so taking it out for the first time is giving me a good chance to understand and learn about it all. I'll let you be the judges of the spec as some is a bit meaningless to me just now:

1835, mag case, forged counterweighted crankshaft.
40x35 heads
100 size cams
AA 92mm thick wall pistons and cylinders
HD oil pump
Compufire electronic ignition
009 dizzy
Empi ICT34 copy carbs


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Nice bits in there but if you wanna get more power out of it ditch those empi carbs and get some proper Weber 40 IDF’s set up right on some nice manifolds. You’ll be seeing 100 hp then. Engle W100 cam I assume? Not an overly sporty cam but will gives plenty of bottom end grunt which is what many want in a bus.

 

[atafonso]

The stock clutch should hold that kind of power just fine. IMHO, the problem was that the cable was "strangled" or the owner has a habit of keeping the foot on the clutch after changing gears.
As per pics, the clutch disc is not even bedded in yet. The blue marks are definitely overheating due to slippage but not caused by lack of pressure of a stock cover. Unless the clucth cover's springs are completely defective or the cover did not fully seat on the flywheel that is.
Abel