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TR6 clutch release bearing

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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1473715 by Tote 3. Why 17 bolts to hold the bell housing onto the engine plate?!!!!!

Tony:

One reason so many bolts is that the bell housing is aluminum, and a casting to boot. So it tends to be brittle and needs loads spread out over a larger area to avoid fractures and cracking. If the housing were cast iron or steel, then many fewer bolts could be used.

Two of the bolts secure the starter motor, which is not light in and of itself and gets a substantial torque applied to it during starting..

The motor/tranny combo is supported at the motor, and at the tail of the transmission. The motor wants to tip over backwards as the motor mounts are not in the center of gravity of the engine. This places a bending moment that is at its greatest where the transmission is mated to the motor. As already explained an aluminum casting is not the strongest choice, hence the number of fasteners.

Lastly I will mention that earlier bell housings (TR4s) had a thinner lip where it attached to the engine. Cracking and breakage occurred, so later castings were beefed up in this area. The TR6 uses the same gearbox as the TR4 but with the thicker casting so none of us have had that particular problem. I mention this simply to point out that design elements of the engine/gearbox attachment have evolved over time and addressed specific problems - some of which were driven by the fact that the bell housing is fragile compared to the engine plate to which it attaches.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

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zs6aa Alf Zeller
Canada   CAN
Hi Brett,
Any update on this topic - how did the Timken TO bearing work out?

Cheers,
Alf

Brett E Brett Evans
Columbus, OH, USA   USA
1973 Triumph TR6 "Scarlet Harlot"
Hey Alf

Jury's still out, but it's my own fault. I became inflicted with "while I'm in there" disease. It started with replacing the clutch and throwout bearing. I then decided to go ahead and change the rear main oil seal while I was in there. Then the u-joints on the main shaft. Then the clutch cross shaft was replaced with one that had grease fittings (along with new longer bronze bushes). When I removed the clutch fork of course it had a broken pin. Both fork and pin were replaced and the fork was cross drilled. Replaced both oil seals in the front gearbox cover and installed a new bronze bearing sleeve with the anti-roll pin. Replaced the rear oil seal in the gearbox rear extension.

Before I could do any of the above I had to get the car from where it was parked to where the work would be done. Due to the bad clutch the car had been sitting for a couple of years and the 2 year battery was now 5 years old and dead. I installed a new Optima yellow top. The tires were dry rotted so all 5 (even the spare) were replaced with Coker Redlines. When I went to move the car I discovered that I had no brakes. Luckily I only had to move the car about a hundred feet from the next door neighbors driveway to my own. Once there I discovered my P.D.W.A. was leaking. I already had a repair kit from TRF so I figured I could fix it after I did the gearbox.

Now comes the fun part. Since I had to drain the brake fluid anyway to fix the P.D.W.A. I decided to install the new rubber brake hoses and rear wheel cylinders I already had on hand. That was when I managed to break one of the 40 year old mild steel brake lines. New stainless steel lines (pre bent) were ordered. "While I was in there" I decided to rebuild the brake master cylinder and both calipers. Then I decided the change the mild steel line coming out of the clutch master cylinder with stainless steel as well. Of course I managed to cross thread the new line when I tried to install it, and of course it wouldn't seal. Ordered a new clutch master cylinder with a larger bore.

Everything was installed and no leaks!!! Then I went to start the car and noticed sparks (I didn't want to install the new plastic gearbox cover until I knew the clutch was working properly) It turns out that the 2 wires that connect to the back of the starter had somehow worked themselves loose and were touching. Goodbye electronic ignition! Replaced with a new Ignitor II ignition and coil.

The latest problem involves getting fuel to the carbs (there isn't any). I got as far as removing the fuel pump but haven't been able to work on the car lately due to work, family and other commitments. It hasn't helped that winter weather in Ohio this year has been frigid to say the least.

When I get the fuel issue figured out I will be able to actually drive the car to test the operation of the Timkin throwout bearing which was the original point of the exercise.

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zs6aa Alf Zeller
Canada   CAN
Hi Brett,
Thanks for response. I have gone ahead and ordered a 3 pce B&B kit from BPNW. No matter how hard and long I searched no-one could say which release bearing is in the kit. When I get it I'll figure out the next step i.e do I use it or find something else. I am doing a full motor and G/box rebuild so it will May before results will be known. We are in the same boat I guess,
Cheers,
Alf

magenta robin cringle
Worthing, west sussex, UK   GBR
on the subject on the clutch release bearing pin I strongly reccomend you email revington in the uk before you do
info@revingtontr.com / https://www.revingtontr.com/search.asp?for=clutch%20bearing for their bearing parts
On my UK 1973 tr6 fitted with the earlier engine I have not used a pin configuration following their advice and using their parts

magenta robin cringle
Worthing, west sussex, UK   GBR
regarding my last post : I have tracked down Revingtons guide note on the bearing pin for clarity but sugget you confirm with them ~
Revington regularly race Trs and have a good reputation here in the Uk

https://www.revingtontr.com/product/147858pb/name/carrier-release-bearing-pb-tr4a-6

The original TR4A part was made from phosphor bronze and is able to spin, resulting in the operating pins finding a new spot to rest at each operation. The TR250, 5 and 6 part whilst physically the same as the TR4A part, was made from steel and incorporated a small pin through the operating pin recess. The change of material would doubtless have taken place on cost grounds, the pin being introduced to stop aggressive wear.
The bad news is that the fact that the carrier does not spin means that the operating pins always stop in the same place, resulting in excessive wear in this one spot.
Our [revington] product is made from very high grade phosphor bronze, has no small pin preventing rotation and as a result no grooves are made by the operating pins.
Carriers were never a problem on TR2-4A's and they were all phosphor bronze

Brett E Brett Evans
Columbus, OH, USA   USA
1973 Triumph TR6 "Scarlet Harlot"
I sourced the bronze sleeve from TRF and I did install the pin per advice from other members on this forum. I did this specifically because I don't want the sleeve to rotate. Allowing the sleeve to rotate creates excessive wear in 2 areas: between the nose cover and sleeve, and between to fork guide pins and sleeve. Wear in both of those areas will eventually cause play in the sleeve and could cause the release bearing to become misaligned. I have yet to hear from anyone that had their clutch fail because the sleeve pin broke, but have heard from people that experienced problems due to misaligned sleeves due to wear.

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Tote Tony M
Kingston, ON, Canada   CAN
Getting a bit confused on this...it should be simple...let me get this straight the gear box nose piece (stationary, fixed in place), the carrier is loose to slide back and forth on the nose piece while being moved by the guide pins on the cross shaft piece. Then the release bearing which is pressed onto the carrier bearing spins freely because its a bearing onto the clutch pressure plate fingers to release the clutch.

It would seem to me that the nose piece was never designed to have anything spinning on it, only sliding. Also those puny cross shaft pins weren't designed to be spun too, just to have some play, not high rpm spinning. So why would Revington say that it is OK for these non-spinning designed pieces to spin at high rpm with a bronze carrier as the sacrificial metal?

Am I reading this right?

dicta dick Taylor
Downey, Callifornia, USA   USA
In reply to # 1513174 by Tote Getting a bit confused on this...it should be simple...let me get this straight the gear box nose piece (stationary, fixed in place), the carrier is loose to slide back and forth on the nose piece while being moved by the guide pins on the cross shaft piece. Then the release bearing which is pressed onto the carrier bearing spins freely because its a bearing onto the clutch pressure plate fingers to release the clutch.

It would seem to me that the nose piece was never designed to have anything spinning on it, only sliding. Also those puny cross shaft pins weren't designed to be spun too, just to have some play, not high rpm spinning. So why would Revington say that it is OK for these non-spinning designed pieces to spin at high rpm with a bronze carrier as the sacrificial metal?

Am I reading this right?

You are!

Dick

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Brett E Brett Evans
Columbus, OH, USA   USA
1973 Triumph TR6 "Scarlet Harlot"
Sometimes we overthink things--Dick Taylor is absolutely correct.

zs6aa Alf Zeller
Canada   CAN
Hi Brett,
I'm still following along, as we are both on the same journey, although mine is the TR4A, but it uses all the same clutch stuff as the 6.

I received my Borg and Beck 3-pce kit, HK 9649, but the release bearing is a no-name/no-number version which is annoying. I may just 'bin' it, so am researching options. like yourself, I'm looking at either the TRF bronze carrier alone, or the combo bronze with fitted bearing on the short list (assume bearing would be Koyo). It seems we have two purchasing issues (a) bearing carrier material and pin application and (b) release bearing choice. The problem is that suppliers describe bearings as "heavy duty" without Manufacturer and numbers.

In addition to the Revington notation, If you check out www.mossmotors.com, bronze carrier # 596-026 and read the Installation PdF. It goes into detail on the different types of carriers available and use of the pin. The Moss bronze carrier apparently has the holes to accommodate the pin, but they recommend not using a pin with bronze - with a steel carrier it seems the pin is required. So I eventually get to my question, are all bronze carriers from the same source? Does your TRF carrier have the pin hole?

Regarding bearings, I am finding it tough to identify a suitable bearing. It seems there are: RHP (no-name cheapo, like in my kit), RHP #14w/2 1/16 (new UK made HD, in Moss kit of B&B ,PP/disc, RHP and bronze), KYK, Koyo land cruiser bearing (in TRF magic clutch (Sachs, LUK, Koyo and bronze), German Gunst (no longer in favour?), Gunst style (BPNW, don't know what that means). When I look at numbers, there are BBHD3269, GRB211, GRB211HD, RB3269 etc. From history, it seems that the declining quality of RHP bearings was the beginning of TR clutch angst, whereas the new RHP marked and numbered bearing may be OK?.

The No-pin use with the bronze carrier also seems intuitively difficult to follow, as there is no mention of how rpm's it spins e.g. 2-3 then stops or continuous at 1000 rpm while clutch engaged. For clutch mechanisms in general, I understand that the carrier/sleeve should not spin, and while there are comments about the bronze application in the 4A , I have not been able to confirm whether they were pinned or not.

Keep your findings coming. I have a lot to learn.

Cheers,
Alf

Brett E Brett Evans
Columbus, OH, USA   USA
1973 Triumph TR6 "Scarlet Harlot"
My bronze sleeve came from TRF and had a hole for the pin but the pin wasn't included. I ordered the pin separately and installed it. The pin is currently listed by TRF as CWE (cease when exhausted) so they may not be available in the future. The sleeve from TRF fit perfectly (there is currently another post about Moss sleeves having too small of an inside diameter). I think TRF makes these themselves and doesn't get them from the same source as other suppliers. The clutch I choose was LuK as they looked to be the closest match to the original Laycock (LuK actually owns Laycock). The LuK came with one of the new HD RHP bearings and I compared it to the Timkin I plan to test. Both bearings appear to be similar in diameter but differ in construction. I think the RHP uses needle roller bearings while the Timken uses ball bearings. To me the Timken looks and feels more solid. The Timken pressed onto the sleeve (using the tool I also ordered from TRF) and spins by hand fairly easily. The gearbox is currently installed and when I can get the car started I'll be able to test it. Things I'll be looking for will include the actual engagement/disengagement of the clutch and noise/squealing/chirping if any. I also fitted a larger diameter clutch master cylinder. I'm really looking forward to trying this combination.

zs6aa Alf Zeller
Canada   CAN
Waiting in anticipation of how your installation works out. So, I will get the TRB bronze carrier and a pin next week, but undecided on whether to get just the carrier or carrier with bearing. I have probably 2 months to decide so maybe you will have positive feedback by then

I may also be inclined to overthink things, but heh, it's winter and not much else to do - pics of my removed clutch and new attached


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zs6aa Alf Zeller
Canada   CAN
Sorry not all the pics uploaded for previous message


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