Clutch Adjustment

[azpaul50]

We're still struggling with this beast down here and now have another problem. First we resurfaced an uneven flywheel that solved the horrendous clutch chatter this car had. Then we installed a rebuilt Gordon's clutch and plate to replace the one the car had. The only apparent difference was that carbon clutch bearing. Now...when the clutch is adjusted where the clashing stops while putting it into gear, we entirely lose clutch pull. When we adjust to get pull, you can't get it into gear without clashing. Anything in between goes mostly to more clashing. My mechanic (who by the way was an actual Amtrac mechanic and whizz with old GMs) is talking about physically changing pivot points and other mechanicals. Anyone out there run into this before? Remember, we have ample evidence that this car has been jury rigged in several areas before. - Paul:032:

 

[DavidC]

Look closely at the cross section of the clutch in the Amphicar manual and see the way the actuation arms run parallel to the flywheel face. It must be setup like this, the arms on the cover can be adjusted. The thickness of the pressure plate is critical here, it must be perfect to the milimetre. You need about 10mm of free play on the cable. Could it be the resurfaced flywheel ? They are plentiful here so nobody ever bothers resurfacing them. You have checked and if necessary changed the engine crank thrust washers ? That can cause clutch and lots of other problems if they are really worn (or have been bodged)

David C in the UK

----- Original Message -----
From: azpaul50
To: david@manbus.com
Sent: Friday, July 11, 2008 10:05 PM
Subject: [General Amphicar Discussion-t-20082] Clutch Adjustment


We're still struggling with this beast down here and now have another problem. First we resurfaced an uneven flywheel that solved the horrendous clutch chatter this car had. Then we installed a rebuilt Gordon's clutch and plate to replace the one the car had. The only apparent difference was that carbon clutch bearing. Now...when the clutch is adjusted where the clashing stops while putting it into gear, we entirely lose clutch pull. When we adjust to get pull, you can't get it into gear without clashing. Anything in between goes mostly to more clashing. My mechanic (who by the way was an actual Amtrac mechanic and whizz with old GMs) is talking about physically changing pivot points and other mechanicals. Anyone out there run into this before? Remember, we have ample evidence that this car has been jury rigged in several areas before. - Paul

 

[EricM]

I'm not much of a mechanic thankfully the group is full of good ones. But when it comes to the Amphicar clutch John Friese has done all the research and tinkering that anybody could need. If I needed a clutch I'd buy his upgraded/updated clutch. Everybody I know who has ones loves it. Since he's spent so much time on the clutch he should also be able to give you some pointers on what you have.

Eric
White 62 - In Chicago (at least for today)


----- Original Message ----
From: azpaul50 <>
To: e_mattlin@sbcglobal.net
Sent: Friday, July 11, 2008 4:05:05 PM
Subject: [General Amphicar Discussion-t-20082] Clutch Adjustment


We're still struggling with this beast down here and now have another problem. First we resurfaced an uneven flywheel that solved the horrendous clutch chatter this car had. Then we installed a rebuilt Gordon's clutch and plate to replace the one the car had. The only apparent difference was that carbon clutch bearing. Now...when the clutch is adjusted where the clashing stops while putting it into gear, we entirely lose clutch pull. When we adjust to get pull, you can't get it into gear without clashing. Anything in between goes mostly to more clashing. My mechanic (who by the way was an actual Amtrac mechanic and whizz with old GMs) is talking about physically changing pivot points and other mechanicals. Anyone out there run into this before? Remember, we have ample evidence that this car has been jury rigged in several areas before. - Paul

 

[jfriese]

Hello Folks,

I wish I could help on this clutch problem you're having but I never was able to get the chatter out of one of my cars original clutches. Two "professional" rebuilds later and it chattered like crazy. That's one of the reasons I designed my improved clutch system. It uses a modern clutch design, does away with virtually all the chatter and is more durable than the original clutch. Getting those old style clutches to work smoothly is pretty much a "pot luck" issue and, given all the work involved in pulling the engine to change the clutch parts, that is certainly NOT what you want to deal with.

John Friese
67 White
67 Red

 

[azpaul50]

John - Actually, the chatter is gone after resurfacing the flywheel! The problem is now clashing the gears. We adjust for smooth gear engagement, we lose clutch pull. We adjust for pull, then it won't go into gear without grinding. ???

To: azpaul50@hotmail.comSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentDate: Sat, 12 Jul 2008 00:24:19 -0400From:



Hello Folks,I wish I could help on this clutch problem you're having but I never was able to get the chatter out of one of my cars original clutches. Two "professional" rebuilds later and it chattered like crazy. That's one of the reasons I designed my improved clutch system. It uses a modern clutch design, does away with virtually all the chatter and is more durable than the original clutch. Getting those old style clutches to work smoothly is pretty much a "pot luck" issue and, given all the work involved in pulling the engine to change the clutch parts, that is certainly NOT what you want to deal with.John Friese67 White67 Red

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[Ken Chambers]

Paul,

I've noticed that clutch pedal travel is minimally adequate to operate
the clutch properly. Clutch pedal free play decreases on my car as
operating temperature increases. Seems counterintuitive. One would
think the cable would lengthen with temperature but the change must be
occurring elsewhere. I have about 3/4 inch of free play when cold
which decreases to about 1/4 inch when hot. That limits clutch
disengagement travel when cold.

Looking further I took measurements of the clutch cable anchor points
and found movement. The triangle bracket on the transmission flexed
substantially, enough to visually observe. I moved the cable closer
to the mounting holes thus substantially reducing the amount of flex.
That made a marked improvement in clutch travel.

The front mount at the pedals had a tiny amount of movement but would
be more difficult to improve without welding in some reinforcement.

Another thing to investigate would be cable stretch but haven't done
that.

Good luck,
Ken Chambers, CA




On Jul 13, 2008, at 4:07 AM, azpaul50 wrote:

> John - Actually, the chatter is gone after resurfacing the flywheel!
> The problem is now clashing the gears. We adjust for smooth gear
> engagement, we lose clutch pull. We adjust for pull, then it won't
> go into gear without grinding. ???

 

[DavidC]

You can rule out the clutch by looking at what happens with the props, do they engage and disengage as normal. If yes then it's inside the land transmission. If it happens on first gear it's prob not syncro rings, if it only happens on the other gears then it may be. To confirm then drive using the double de-clutch method (learn the technique on someone elses car- ideally a rental) using this method you remove the need for syncro and so should be able to tell if it's something else.

David C
----- Original Message -----
From: azpaul50
To: david@manbus.com
Sent: Sunday, July 13, 2008 12:07 PM
Subject: RE: [General Amphicar Discussion-t-20082] Re: Clutch Adjustment


John - Actually, the chatter is gone after resurfacing the flywheel! The problem is now clashing the gears. We adjust for smooth gear engagement, we lose clutch pull. We adjust for pull, then it won't go into gear without grinding. ???

To: azpaul50@hotmail.comSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentDate: Sat, 12 Jul 2008 00:24:19 -0400From:



Hello Folks,I wish I could help on this clutch problem you're having but I never was able to get the chatter out of one of my cars original clutches. Two "professional" rebuilds later and it chattered like crazy. That's one of the reasons I designed my improved clutch system. It uses a modern clutch design, does away with virtually all the chatter and is more durable than the original clutch. Getting those old style clutches to work smoothly is pretty much a "pot luck" issue and, given all the work involved in pulling the engine to change the clutch parts, that is certainly NOT what you want to deal with.John Friese67 White67 Red

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[Midwest Amphicar]

Just curious was Your "rebuilt" pressure plate covered in silver paint? If it is ....well....be wary. When You pull back out look at arm that holds release bearing. They do fatigue. Also do the "jiggle" test on Your input shaft-manual calls it drive shaft- If it has lots of up and down movement, your trans will need attention. If You run it with lots of play You will ultimately need a new shaft. It is very expensive. If ok at least replace the seal. Clean hole out with brake clean or similar. I use a dab of Indian head shellac on outside seal surface. Then after in a couple of punch marks-go easy- Never use silicone/rtv glues. Also clean outside edge of seal before install. Later Dave the Wave,P.S. I have done lots of transmissions now,so if You need more help just call.

 

[jfriese]

Hello Again,

For what it's worth, there is 3/4" of movement from unpressed pedal to fully pressed on the clutch cable of my cars. That measurement is taken by simply pulling the slack out of the cable by hand and having someone press the clutch pedal. Some of these cars had a clutch pedal stopper screw under the pedal arm. Be sure this is fully turned down for maximum movement.

John Friese
67 White
67 Red

 

[azpaul50]

Double clutching doesn't make much of a difference especially into first gear. The props turn fine in either direction although that is in a static condition and not under water load. God forbid that this vehicle makes it into water anytime soon. I was afraid you were going to say transmission...

To: azpaul50@hotmail.comSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentDate: Sun, 13 Jul 2008 12:40:36 -0400From:



You can rule out the clutch by looking at what happens with the props, do they engage and disengage as normal. If yes then it's inside the land transmission. If it happens on first gear it's prob not syncro rings, if it only happens on the other gears then it may be. To confirm then drive using the double de-clutch method (learn the technique on someone elses car- ideally a rental) using this method you remove the need for syncro and so should be able to tell if it's something else. David C ----- Original Message ----- From: azpaul50 To: david@manbus.com Sent: Sunday, July 13, 2008 12:07 PMSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentJohn - Actually, the chatter is gone after resurfacing the flywheel! The problem is now clashing the gears. We adjust for smooth gear engagement, we lose clutch pull. We adjust for pull, then it won't go into gear without grinding. ???To: azpaul50@hotmail.comSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentDate: Sat, 12 Jul 2008 00:24:19 -0400From: Hello Folks,I wish I could help on this clutch problem you're having but I never was able to get the chatter out of one of my cars original clutches. Two "professional" rebuilds later and it chattered like crazy. That's one of the reasons I designed my improved clutch system. It uses a modern clutch design, does away with virtually all the chatter and is more durable than the original clutch. Getting those old style clutches to work smoothly is pretty much a "pot luck" issue and, given all the work involved in pulling the engine to change the clutch parts, that is certainly NOT what you want to deal with.John Friese67 White67 Red__________________________________________________ _______________Need to know now? Get instant answers with Windows Live Messenger.http://www.windowslive.com/messenger...ssenger_072008

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[azpaul50]

No silver paint...just the metal "unfinished" finish. As for the drive train in general, the pilot bushing thickness were very thin but not out of round. We replaced it finding not movement of the shaft by hand.

To: azpaul50@hotmail.comSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentDate: Sun, 13 Jul 2008 12:57:54 -0400From:



Just curious was Your "rebuilt" pressure plate covered in silver paint? If it is ....well....be wary. When You pull back out look at arm that holds release bearing. They do fatigue. Also do the "jiggle" test on Your input shaft-manual calls it drive shaft- If it has lots of up and down movement, your trans will need attention. If You run it with lots of play You will ultimately need a new shaft. It is very expensive. If ok at least replace the seal. Clean hole out with brake clean or similar. I use a dab of Indian head shellac on outside seal surface. Then after in a couple of punch marks-go easy- Never use silicone/rtv glues. Also clean outside edge of seal before install. Later Dave the Wave,P.S. I have done lots of transmissions now,so if You need more help just call.

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[PeterP]

That's one of the reasons I designed my improved clutch system. It uses a modern clutch design, does away with virtually all the chatter and is more durable than the original clutch.

This is right near the top of my "to buy" list. The transmission has been my primary area of concern, mechanically. I'm pretty much resigned to putting money away until I can just ship the Tranny to Dave, have him work his magic on it, and install the new clutch all at the same time.

Of course, there is a lot of blasting, priming, blocking, painting, re-chroming, and replacing every darned bit of rotting rubber on the car before I get to that point.

Someday.

 

[Canadian four amphs]

1st things first.... throw out everything and buy Johns Friese clutch
for what you get its a good price and it works..
have 2 in 2 of my cars.. put them in all my rebuilds now, Just put one in Ricks car on weekend, Smoooooothest yet.
just put in remove cable free ply and go.
Originals..
The 3 ajustable arms are in too far.. loosen lock nuts and bring ring out a bit. test out of car to make sure there is NO wobble here!I use a dial indiator and run engine on bench.

next,, Chuch Cuch had this ame problem a few years ago,, His shaft had be wet and rusted in spline. I know yours is to fresh for that but I belive it could be snaging on shaft or pilot bearing..Did you put a new brass pilot in.. see Johns pic above,
GORD Canadian 4 Amphs.

 

[azpaul50]

John - I left a message on you machine. Trying to order one of your clutches. We've finally given up on the rig I bought elsewhere. Also looking for a clutch release fork if anyone has one. We're applying the change everything until something works! - Paul

To: azpaul50@hotmail.comSubject: RE: [General Amphicar Discussion-t-20082] Re: Clutch AdjustmentDate: Sun, 13 Jul 2008 15:08:19 -0400From:



Hello Again,For what it's worth, there is 3/4" of movement from unpressed pedal to fully pressed on the clutch cable of my cars. That measurement is taken by simply pulling the slack out of the cable by hand and having someone press the clutch pedal. Some of these cars had a clutch pedal stopper screw under the pedal arm. Be sure this is fully turned down for maximum movement.John Friese67 White67 Red

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[jfriese]

Hi Paul,

I was at the lake today and must have missed the vibration on my phone. I'll call you on Monday (later today) and work out the details. I have the clutch systems in stock and ready to go.

Thanks,

John Friese
67 White
67 Red

 

[okey0]

. Also do the "jiggle" test on Your input shaft-manual calls it drive shaft- If it has lots of up and down movement, your trans will need attention. If You run it with lots of play You will ultimately need a new shaft. It is very expensive. If ok at least replace the seal.

Is there a standard for this "jiggle"? I have SOME movement, I figure that's a given since the end of the shaft is so far from the bearing. I see no mention in the manual of how much jiggle or movement the shaft should have.

 

[jfriese]

What's makes this adjustment a bit hard on an Amphicar is the slop in the clutch cable system. The way I do it is to go at it with the rear seat out, hook my left hand middle finger over the clutch fork arm and pull it until it stops hard. Use my right hand to pull the slop out of the clutch cable by pulling towards the back of the car at the threaded gizmo at the end of the cable and holding that position by the thumb and index finger of my left hand. Now, using my right hand again I adjust the special clutch cable nut until all the slack is gone. I then back it out a turn or two so that the fork arm has about 1/16 inch of free play. The whole idea of this type of clutch adjustment is that the release bearing is lifted away from the clutch disk when your foot is off the pedal. What lifts it away is that light spring tension you noticed when pulling on the clutch fork. Too little free play and the release bearing will constantly drag on the clutch and they just aren't designed for that and will fail. Too much and the release point of the clutch will have the pedal too far down near the floor.

These adjustments are standard stuff for a cable release clutch system. Amphicars just make the pieces harder to get at.

John Friese
67 White
67 Red

 

[okey0]

John, I'll definitely use your tip when I install your clutch system. My question above has to do with the input shaft itself. Since the bearing is on the opposite side of the differential, I figure some wiggle is ok, I just wonder how much. I'd say the end of the shaft (the end that will snug up to the brass bushing that's on the end of the crank) has about 1/32 to 1/16" of wiggle from side to side. I'm HOPING that is ok, and that the bushing is there to minimize that wiggle once the transmission and engine are mated up.

 

[Ken Chambers]

The oilite pilot bushing should be a slight interference fit in the crankshaft bore to hold it in place. The ID of the pilot bushing should be a close loose fit (about .002"-.003") on the transmission input shaft. Here's an article on the subject: http://www.crankshaftcoalition.com/wiki/Pilot_bearing_and_bushings

I elected to reuse the original pilot bushing when installing John's new clutch system as it was a very close fit. His supplied bushing was too loose in both the crankshaft as well as on the input shaft, as you describe. Sorry John, can you improve on those pilot bushings on an otherwise superb clutch system?

The transmission shaft does have a lot of side play but is held in position on the clutch end by the pilot bushing which should fit very closely.

 

[jfriese]

Hi Ken,

Those bushings come from either of the two largest replacement parts houses for Triumph Spitfire engine parts and the parts themselves come from England. I have no say as to exactly how they are machined. None the less, they have been used for many years and whatever tolerances you might run into have always been fine. There has always been some variance in these bushings because even Hugh Gordon talked about how some of them simply fall out of the crankshaft when the flywheel is removed. The flywheel holds them in place anyway. These tiny variations have no effect on how well the clutch works. There are critical tolerances in some parts of my clutch system but this is not one of them.

John Friese

67 White
67 Red