BJ7 Slipping Clutch? rear main seal?

[twas_brillig]

https://www.britishcarforum.com/bcf...the-risk-to-install/page2&highlight=rear+seal

We've owned our 65,000 miles from original 1962 Mk II BJ7 for many years, but it's only had a couple of seasons on it driving. A shop installed a Toyota transmssion for us two years ago and we drove it some the following summer before sending it back to the shop for a paint job that grew into a year and a half or so of spa treatment. We picked it up Monday and put maybe 50 miles on it and identified a differential whine (we'd had Lempert 3.54 gears installed); the shop busted butt and worked late reinstalling the 3.91s so we could head out to the Van Dusen All British Field Meet for this weekend but I noticed clutch slip as I drove home - neither I nor the shop had noticed this in our road testing and driving over the previous few days. The clutch slip was very obvious (3rd gear, for example, 40-50 mph and step on the gas). When I took it back to the shop, the mechanic test driving ran us up a couple of steepish hills, and no slip. He did get a reduced amount of clutch slip going up a gentle hill in 3rd at about 40 mph (speedo not calibrated so guestimating); there was oil drips on the bottom of the exterior of the Toyota/kit bell housing

We're getting the differential checked out and the shop will pull the transmission when the diff gets changed out again and have a look at the disc/pressure plate/etc. We've never run into this clutch slip issue and the stock Healey sealing system has never been disturbed.

I tried doing a search on the Forum but not successfully regards slipping; I did find the above thread regards rear main oil seals.

So, two questions:
- anyone got any ideas as to what the heck is going on (and what to do about it).
- if the clutch disc does turn out to be oil contaminated, any comments on the various rear main seal kits (I've found a round one as well as a square one, from various retailers)

Thanks, Doug (who is Confused in Calgary)

 

[steveg]

The differential whine should be able to be adjusted out.
I believe some of the new Toyota clutch discs are close to the minimum as-worn thickness of the original Healey disc and therefore don't take that long to start slipping.
My first (OEM) disc started to slip after about 1500 miles.
California clutch makes discs a little thicker: https://californiaclutch.com/
These have worked fine in my Toyota setup.
I've developed a technique for installing the crank seal with the spring forward. Use plenty of sealant between the seal carrier and engine block.
See: https://www.pbase.com/stevegerow/image/91637854

At one time I had a master cylinder or hose which was somehow keeping pressure on the disc and that may have contributed to the slippage.

BTW - you can mount and operate the clutch with the trans off the car but the bell-housing in place - so you can observe if it's operating through the entire range of motion. Use a pilot tool in place of the first motion shaft.

My Toyota setup is the earlier Smitty so there were some "fiddles" to get it adjusted correctly. I needed a longer ball-post and a different-length pushrod for the operating lever to operate correctly. I believe the newer setup no longer has these issues.

 

[Bob_Spidell]

I just had my BJ8's engine rebuilt by a mechanic who I consider to be a master, and who is incredibly meticulous. He's also a licensed A&P: Airframe and Powerplant mechanic; i.e. he makes airplanes run and fly (well, money makes airplanes fly but he helps). I'd purchased a rear main seal kit years ago--from Moss--and had asked him to install it as part of the overhaul. He all but refused; saying there was no way to return oil to the sump after the seal, presumably, retains it in the engine. I'm paying this man lots of money so, for once, I took advice and he improved on my Nock PCV installation by running pipes to both carburettors. I just today returned from a 2-day trip up the California coast, about 150 miles each way, and the engine did not leak a single drop of oil (I swear on a stack of Bentley manuals). I also had 250 miles on the engine before the trip and, again, not a drop on the ground. We've had the PCV, er, 'discussion' several times before--and, yes, this isn't a true 'system' because I don't have an air input source--but those are my results. Others with seals will chime in, but from what I've heard many times they still leak, at least a little, quite possibly because of the 'non-return' issue.

Before my engine was overhauled I had the typical 'Healey drip' out of the drain hole in the bellhousing. Last year my clutch started to slip, similar to your experience, and I figured the oil getting past the scroll 'seal' was at least partially responsible. However, on teardown inspection my clutch disk was dry, but the clutch was worn thin and a couple of the springs were broken (I think this caused the occasional judder I experienced). So, I think Steve is on to something if you have a clutch disk that was thinner to begin with; my clutch had about 120K miles on it before it started to slip.

I also have a Lempert 3.54 rearend, and it's whined a little for as long as I can remember. My dad and I installed it with crude tools, but I've heard from others that theirs whine as well, and some were set up by 'pros.' Some diffs seem to whine more than others; my 2008 Mustang GT has a noticeably whine with a 3.71.

 

[DerekJ]

Bob, nobody wants a Healey that doesn't drip oil. That just isn't right!:wink-new:

 

[Bob_Spidell]

Bob, nobody wants a Healey that doesn't drip oil. That just isn't right!:wink-new:

Don't worry ... it's only a matter of time. I think I see a bit of oil starting to come out around the backside of the balancer/crank pulley. Am I the only one who's never been able to keep the front of the crank sealed up for long? I'm guessing the flexing of the crankshaft may cause premature wear on the seal and, yes, I know to center the seal on the crank before tightening the timing cover bolts.

WRT: "We're getting the differential checked out and the shop will pull the transmission when the diff gets changed out again and have a look at the disc/pressure plate/etc. We've never run into this clutch slip issue and the stock Healey sealing system has never been disturbed."

Dunno about the Toyota setup, but a leaky front seal on the gearbox can create or contribute to a leak from the bellhousing. Our BN2 had sat for years and once, after a drive, it peed oil on the garage floor. On teardown, we found that the gearbox seal was so hard the rubber crumbled when we removed it. After my BJ8 engine overhaul, I accidentally overfilled the gearbox by at least a half quart. Thinking 'no big deal,' I drove it a short distance and it too peed on the floor. After I lowered the level in the gearbox that leak stopped (and, of course, I'd spent an hour cleaning the bellhousing of grime).

While I'm on topic, I wondered why the inside of my bellhousing was so caked with grime; i.e. the 'oil + dirt' variety. Besides the drain and starter holes, the only other opening was a 9/16" hole on the housing for the release bearing (necessary if you ever need to replace the bushings on the throwout fork--we did). Because I do sometimes take the BJ8 'off the beaten path,' I'm guessing enough dust gets into that hole to make a mess. I bought a plastic plug to cover the hole.

 

[Keoke]

Don't worry ... it's only a matter of time. I think I see a bit of oil starting to come out around the backside of the balancer/crank pulley.

Am I the only one who's never been able to keep the front of the crank sealed up for long?

BOB:
Along time ago Timing covers were machined to take modern seals and were available on an exchange basis
Do not remember Who did it but that was my answer.

 

[Bob_Spidell]

BOB:
Along time ago Timing covers were machined to take modern seals and were available on an exchange basis
Do not remember Who did it but that was my answer.

My cars HAVE 'modern' seals; the BJ8 came with them, and we had the BN2's cover machined (actually, IIRC, it was an exchange cover from BCS). Maybe too much oil gets in the covers?

 

[Keoke]

My cars HAVE 'modern' seals; the BJ8 came with them, and we had the BN2's cover machined (actually, IIRC, it was an exchange cover from BCS). Maybe too much oil gets in the covers?

Next time timing cover is off Check oil galley plug at left top of block many times I have found them loose. Just drive back in and fill small void with JB -Weld.

 

[Bob_Spidell]

Next time timing cover is off Check oil galley plug at left top of block many times I have found them loose. Just drive back in and fill small void with JB -Weld.

Will do. Thanks.

 

[twas_brillig]

Anyone have figures as to what the min/max thicknesses would be for a BJ7 clutch disc and the Toyota disc? Anyone know if Mr. Delaney would have provided a stock Toyota disc in his kit? I'm going to order a rear main seal just in case, but not install it unless the clutch disc appears oil soaked. I've dropped a note to California Clutch and will try to touch base with Mr. Delaney next week as well. Thanks all. Doug

 

[bob hughes]

Derek you are a wag!!

When my stock clutch on my BJ7 started to slip (and yes oil dripped from that little hole) I pulled the gearbox and set about establishing exactly what clutch was in there, ( you can never tell these days with mix and match) whilst doing that I found that the thrust bearing was shot, the clutch housing was shot - springs were broken and the fork mechanism in the bell housing needed new bearings. The driven plate was not exactly wet with oil and seemed to have meat on it but I guess oil had soaked in. I ended up buying a new clutch set up complete, the fork bearings were renewed and the installation of that rear oil seal. You do not know what is wrong just through a slipping clutch.



Bob

 

[twas_brillig]

We took the BJ7 into the shop this morning so they can have a look at the clutch (plus tidy few other things). I'd left a message for Pete Delaney yesterday, and he was good enough to call back this afternoon! He suggested going through the linkage and adjusting the 5/16" slave cylinder rod that comes with the kit, as he hasn't heard of any problems related to the disc (which is the stock Toyota part). We're out of town for a few weeks but will sure pass on whatever we learn. Doug