Clutch Stalls Engine

[AUSMHLY]

Hello everyone. Appreciate your help please.

1964 BJ8. Just tuned the car. Idle 800, depress clutch and idle drops to about 700. Spark plugs coffee color, timing 15 degrees. Car runs great when driving! No clutch issues, tranny issue I'm diving into.

Next day, having transmission issues, I remove the tranny, notice the clutch release bearing is blue colored. Why is that? I don't ride the clutch. It concerns me. I replaced some tranny parts trying to figure out what's making a whining/whirring sound in 2,3,4. I re-install the tranny and still have the whining noise.

Now 800 idle, depressed clutch and the idle will drop till the car stalls. Takes about 5 seconds. What's going on?

I need to remove the tranny again to figure out what's making the tranny noise. I thought about first re-tuning the car, but feel I should R/R the tranny first and see if the clutch/idle issue goes away.

Recently (100 miles ago) new clutch assembly, throw out bearing, slave cylinder and slave hose. Interesting that I now have a clutch issue after R/R tranny.

Thoughts?

 

[bobhustead]

Throwout bearing is blue because it has been VERY hot. When you push in the clutch, the T/O is not turning and the friction is dragging down the engine RPM.
Bob

 

[WHT]

Hard to know without more information. Could the release bearing be in contact with the clutch when driving (incorrect air-gap)? Maybe, its not seated in the fork correctly? Is there a problem with the assembled clutch springs/"fingers"?

Before removing your transmission, have you tried to use an inspection probe to look at the clutch and release bearing? It can be inserted through the clutch fork opening (with the engine OFF ) to view the clutch fingers (diaphragm), springs, release bearing, clutch plate, fork, etc. An assistant can gently depress the clutch to watch moving parts. And, newer probes have better cameras than my 10 year old model.

I used one to check the release bearing air-gap when installing my T-5 transmission (there are several different release bearings, or you might have purchased one that doesn't fit properly). With patience, you can directly image many of the internal parts and often see problems with their in-place, installed fitment. You can't understand some problems as easily with the transmission removed.

Always good to check the easy stuff first, then progress as needed.

Regards, Bill

 

[AUSMHLY]

Thanks Bill. The clutch assembly is a HD Borg and Beck, HE4562 7138. It has a round release/pressure plate attached to the fingers, not the triangle shape.
I was getting vibration at the clutch pedal and found I had a bad slave cylinder. New one installed, with a flush solved the problem. I removed the rubber boot at the slave, took close up videos the Throw Out Bearing travel. I'd move the fork by hand so the throw out bearing is not in contact with the Release Plate. When I released the fork, the throw out bearing would travel back to constant contact with the release plate. No air gap.

I'm assuming that there will always be contact between the two being the slave cylinder's rod is always under fluid pressure (clutch pedal not depressed) pushing the TOB against the RB.

What is your Image 1?
Image 2,3 shows your air gap?

How do I find/fix my no air gap problem? Currently it seems like it's riding the clutch which would explain the blue color. Not good, just as I'm wearing down the carbon throw out bearing excessively.

 

[AUSMHLY]

Throwout bearing is blue because it has been VERY hot. When you push in the clutch, the T/O is not turning and the friction is dragging down the engine RPM.
Bob

Thanks Bob. This is true. However I didn't have dragging down the engine RPM before I R/R the tranny. Before RMP was 800, clutch depressed 700 which I think is ok. Now 800 to engine stall. I think part of the problem (blue pressure/release plate) is there is no air gap between the two parts and it's like riding the clutch heating up the pressure/release plate so much it turns blue.

 

[AUSMHLY]

Would someone please provide the correct name for these two parts?
1) The round or triangle piece or metal attached to the clutch pressure plate fingers.
2) The carbon donut that is attached to the clutch fork.

I really should use the correct name in my posts.
Thank you.

 

[WHT]

Hi AUSMLY.

Hydraulic operated release bearings should have an air gap when initially setup IMO. I came to Healey's from other cars, but people used to spend more time setting up hydraulic clutch mechanisms "in the day" to ensure they operated smoothly without binding; and had sufficient travel. People don't really worry as much about it today.

The optimum air-gap might be around 0.100-inches to 0.150-inches given the mounted position of the slave cylinder and length of the pushrod (depending on the car and release bearing mechanism/travel). Different slave cylinders can have variations in their installed position and cylinder travel (for example, Girling travel/throws are 1.375-inches and many aftermarket are only 1.25-inches); and you can purchase longer pushrods and/or shorten them as needed to adjust the air-gap.

Make sure there is no pressure in the hydraulic line and the bearing is at its fully backed-out position during setup. The air-gap will only appear to be present during setup BEFORE bleeding (pressurizing) the slave cylinder and hydraulic lines, and will usually disappear during normal operation as you say. However, the bearing should only initially contact the clutch pad, BUT NOT APPLY SIGNIFICANT PRESSURE on the fingers of the clutch during normal operation with the clutch released (the bearing will retract slightly when the engine is operating and the clutch is released when setup correctly).

Too little gap will keep constant pressure on the fingers, which can make the clutch slip, wear down the surface of the fingers and overheat the release bearing. Too much gap will result in insufficient bearing travel.

A number of people have designed retraction systems using springs to retract the release bearing if it has not been setup correctly (as seen on the MG and other car forums). Springs retract the release bearing back slightly to help prevent it from applying significant pressure to the plate release pad when the clutch is released.

We all setup our cars differently depending on our beliefs and prior experiences.

Regards, Bill

EDIT: the second two images show the air-gap. The first picture is a random clutch bolt.

 

[Bob_Spidell]

Would someone please provide the correct name for these two parts?
1) The round or triangle piece or metal attached to the clutch pressure plate fingers.

AHS calls it a 'thrust pad.' I've heard it called a 'platen' (close enough for me).

Clutch Release Bearing | Race Ball Bearing | BN4 to BJ8

www.ahspares.co.uk

The 'fingers' are part of a diaphragm clutch, hence could be called the diaphragm.

2) The carbon donut that is attached to the clutch fork.

'Release' (Brit) or 'throwout' (American) bearing. It's one piece; but you could call the carbon part a 'bush' or 'bushing.' In a generator or starter it would be called a 'brush,' but I don't think that works in this application.

My guess would be a problem in the clutch M/C, not allowing fluid to return to the reservoir after application (IIRC, you replaced the flexible hose?).

Edit: I just noticed AHS specs different bearings for different cars (news to me). Is it possible you have the wrong one for your car installed?

 

[BobHaskell]

John,
Info from the Healey mailing list back in 2008:

• clutch diameter: 9.5"
• uninstalled pressure plate height: 2.5"
• distance from center of throw out bearing pivot to the front edge of the bearing housing (not the carbon doughnut): 1.0"
• Borg & Beck number on the housing: 4122

Earlier cars had taller pressure plates and shorter throw out bearings.

Sitting here, way out in left field, I wonder if you may have worn crankshaft thrust bearings. Does the crankshaft move when you push it into the gearbox and then push the clutch in? Probably want to use an dial/test indicator to measure.

 

[AUSMHLY]

Bob, learn as I go.
"I wonder if you may have worn crankshaft thrust bearings."
Could you post an exploded photo showing those parts?

Could the issue be the housing? The 3 available below don't have the reference number you mentioned, 4122
1st photo AHS sells a Borg & Beck with the triangle for the BJ8. Per their website, photo show HB4526
2nd photo (click the link in blue) Moss sells a AP brand, triangle, no reference number. 021-139_1.jpg
3rd photo The Borg & Beck I have, round, HE4562

 

[Bob_Spidell]

Your 3rd photo doesn't look correct to me; you sure the part# is correct?

New Ferrari 308/328 OEM Borg & Beck HE4562 pressure plate clutch kit P/N 121562 | eBay

Find many great new & used options and get the best deals for New Ferrari 308/328 OEM Borg & Beck HE4562 pressure plate clutch kit P/N 121562 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Search for 'HB4526' turns up nada.

"Over the last few years some Company’s are claiming to be selling Borg & Beck Clutch Kits and Pieces. These parts are not boxed Borg & Beck. If the parts you are ordering are not in a Borg & Beck Box they are not Borg & Beck, no matter what! If you truly want Borg & Beck, the leader in the British Clutch market, make sure it is in a Borg & Beck box."

Clutch Kit 3-pc Borg and Beck BN7, BT7, BJ7

Your One Stop Shop For All Your British Automotive Parts. Order Online Today! We Have The British Auto Parts That You Are Searching For. Order Today! No Sales Tax. Fast, Courteous Service. Rich Selections. Order Hard To Find Parts. Family Owned & Operated. Fast Shipping.

www.bpnorthwest.com

 

[AUSMHLY]

Your 3rd photo doesn't look correct to me; you sure the part# is correct?

New Ferrari 308/328 OEM Borg & Beck HE4562 pressure plate clutch kit P/N 121562 | eBay

Find many great new & used options and get the best deals for New Ferrari 308/328 OEM Borg & Beck HE4562 pressure plate clutch kit P/N 121562 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Search for 'HB4526' turns up nada.

"Over the last few years some Company’s are claiming to be selling Borg & Beck Clutch Kits and Pieces. These parts are not boxed Borg & Beck. If the parts you are ordering are not in a Borg & Beck Box they are not Borg & Beck, no matter what! If you truly want Borg & Beck, the leader in the British Clutch market, make sure it is in a Borg & Beck box."

Clutch Kit 3-pc Borg and Beck BN7, BT7, BJ7

Your One Stop Shop For All Your British Automotive Parts. Order Online Today! We Have The British Auto Parts That You Are Searching For. Order Today! No Sales Tax. Fast, Courteous Service. Rich Selections. Order Hard To Find Parts. Family Owned & Operated. Fast Shipping.

www.bpnorthwest.com

Hello Bob, when you click on the 3rd picture it will show the part number HB4526 is printed on it.

 

[red57]

Regardless of the part numbers, I agree with Bob, the one shown in the 3rd picture with the round 'platen' sure does look visually different than any I have used for a BJ8 - in fact, I've never had one with a round platen. The 'fingers' look shorter and the overall shape of the metal cover is different, and the platen looks bigger in diameter. It maybe the correct part and they have just updated some portions resulting a different looking part? I'd contact whoever you bought it from and ask for some reassurances it is the correct one.

 

[Bob_Spidell]

re: "... when you click on the 3rd picture it will show the entire assembly. Part number HB4526 is printed on it."

I see 'HE4562' at about 11 o'clock; the other two are labeled 'HB4562.'

Looks like I got the part#s scrambled as well, but in your previous post the first two are labeled 'HB4562'--clearly the same pic--and the third one is 'HE4562' and, like Red said, clearly isn't the correct clutch cover. I'm gonna go out on a limb and say you got one of the 'counterfeit' cover plates; do you still have the original packaging and the seller's name? Hard to tell from a 2D photo but it looks to be thicker than the correct one, which would certainly explain a seared release bearing.

 

[AUSMHLY]

re: "... when you click on the 3rd picture it will show the entire assembly. Part number HB4526 is printed on it."

I see 'HE4562' at about 11 o'clock; the other two are labeled 'HB4562.'

Looks like I got the part#s scrambled as well, but in your previous post the first two are labeled 'HB4562'--clearly the same pic--and the third one is 'HE4562' and, like Red said, clearly isn't the correct clutch cover. I'm gonna go out on a limb and say you got one of the 'counterfeit' cover plates; do you still have the original packaging and the seller's name? Hard to tell from a 2D photo but it looks to be thicker than the correct one, which would certainly explain a seared release bearing.

Sorry for the misinformation.Photos 2 and 3 were the same. I've made the change on the post now.

 

[BobHaskell]

Bob, learn as I go.
"I wonder if you may have worn crankshaft thrust bearings."
Could you post an exploded photo showing those parts?

Could the issue be the housing? The 3 available below don't have the reference number you mentioned, 4122
1st photo AHS sells a Borg & Beck with the triangle for the BJ8. Per their website, photo show HB4526
2nd photo (click the link in blue) Moss sells a AP brand, triangle, no reference number. 021-139_1.jpg
3rd photo The Borg & Beck I have, round, HE4562

See Moss' exploded drawing of internal engine parts; Item 45. They keep the crankshaft from moving fore/aft.

What's the uninstalled height of the pressure plate (housing)?

 

[Patrick67BJ8]

Hello everyone. Appreciate your help please.

1964 BJ8. Just tuned the car. Idle 800, depress clutch and idle drops to about 700. Spark plugs coffee color, timing 15 degrees. Car runs great when driving! No clutch issues, tranny issue I'm diving into.

Next day, having transmission issues, I remove the tranny, notice the clutch release bearing is blue colored. Why is that? I don't ride the clutch. It concerns me. I replaced some tranny parts trying to figure out what's making a whining/whirring sound in 2,3,4. I re-install the tranny and still have the whining noise.

Now 800 idle, depressed clutch and the idle will drop till the car stalls. Takes about 5 seconds. What's going on?

I need to remove the tranny again to figure out what's making the tranny noise. I thought about first re-tuning the car, but feel I should R/R the tranny first and see if the clutch/idle issue goes away.

Recently (100 miles ago) new clutch assembly, throw out bearing, slave cylinder and slave hose. Interesting that I now have a clutch issue after R/R tranny.

Thoughts?

At the end of this thread you will see some archive links. Click the link for May 17, 2017, “Pushing the clutch let’s idle speed drop until the engine stalls”.

You said that you had a good idle until you R&R the transmission for work.
FYI, Most BJ8’s do not idle properly after first start ups especially when they are warm/hot. Drive it around the block and check the idle. You did t do anything to the thrust washers when you R&R the trans and imo, you can rule those out.

Could something you did to the transmission be binding?