Overdrive

[canuck]

I'm a new Healey owner, having got the car just before winter set in in the Great White North. I am sure there have been threads on overdrive problems before, but I haven't run into the symptoms I have, which are as follows:

Flipping the switch while accelerating produces no noticeable behaviour change, either to speed or revs.

Taking my foot off the accelerator with the overdrive switch on causes the revs to drop...much faster than if I take my foot off with the overdrive switch on. In the second case, the revs reduce slowly, as engine speed is maintained by the inertia of the car. In the first, it is as if I had depressed the clutch pedal. If I touch the gas, I get a lurch, as the car's forward motion is out of sync with the engine speed.

It is as if the overdrive were working like the centrifugal clutch I once had in a Citroen 2CV...I fear for my U-joints as I did then when the engine reengages after losing revs, but the car is still moving quickly.

I had the switch and solenoid checked and the overdrive does seem to engage...you can feel it on the right of the gearbox in the car when it isn't running but the switch is on, but not when it isn't.

Anyone had any experience with these symptoms or can shed any light...my mechanic is poring over his manuals but doesn't yet know where to start.

Thanks,

Canuck

 

[Healey 100]

Canuck

Your overdrive is halfway engaged. When that happens, the unit goes into neutral and an overrunning clutch in the device keeps power going to the rear wheels when accelerating -- but the engine goes to idle and the car coasts if you let off the gas.

Possible causes: Not enough oil in the unit, worn oil pump, leakey actuating pistons, overdrive solenoid improperly adjusted.

The last item can be checked by driving the car with the transmission cover off and activating the OD with the manual lever. If it engages then, chances are your solenoid is not opening the activating valve fully.

Good luck, it is probably one of the above -- or perhaps more suggestions from others. Hopefully it is just too little oil and a solenoid, the other problems require rebuild or at least disassemnbly of the OD.

Bill.

 

[Dave Russell]

Canuck,
As mentioned above, the OD appears to be free wheeling. The OD operating pistons move a clutch which engages a brake ring in one position & a cone in the other position. Failure of the pistons to completely retract leaves the clutch somewhere in the middle & it free wheels. This failure to retract can be caused by the operating valve under the ball valve having it's very small internal passage fully or partially blocked.

The discussion of this obscure problem is copied from Moss motors Tech Tips;
-------------------------------------
Overdrive Faults

Fully 90% of overdrive problems that are not electrical faults are
traceable to either the gear oil level being tool low, or an improper
adjustment of the solenoid, so we'll skip these and concentrates on the
others.

An overdrive that fails to engage can sometime be traced to dirt between
the check ball and seat in the pressure regulator valve, or sometimes to
a badly worn pump. Both are quite rare, though possible, so don't
overlook them. Worn or broken rings on the operating pistons or the
accumulator piston can make for a lazy-shifting or slipping unit.

----However, the real winner is a partially or completely blocked bypass port in the operating valve. The valve, which is activated by the solenoid through the operating shaft and lever,has a small hole bored in it (about .018") which is very easily blocked by dirt, etc. The results of blockage can be really fun to find. First, partial or intermittent blocking results in slow engagement, but most noticeable is that there is no compression-assisted slowdown. The unit appears to hang between overdrive and direct drive and feels like it is not in gear. Basically, what is happening is that the partially blocked valve will
not allow the oil to return to the sump fast enough, and the pressure build-up above the valve tries to engage the overdrive while the unit's
springs try to engage directly, and there we hang beween the two. The fun begins when the bypass port becomes completely blocked. Above a
certain speed, the pressure above the valve becomes high enough to engage overdrive, no matter what you do or where the switch is.

Fortunately, the valve blockage is easy to repair. With the transmission tunnel removed, the access to the valve is on the right side of the top of the overdrive unit and is under a 7/16" plug. Under the plug is a spring and check ball assembly which can be removed with a small magnet. After it is cleaned, it can simply be set back in place, hole-in end facing up, followed by the ball and spring assembly. It is very straightforward and easy to remedy once you find it.

Ken Gillanders
Temple City, CA
----------------------------------------
Other possibilities are covered in these links. Pay special attention to solenoid/operating valve adjustment.

https://www.team.net/www/healey/tech/big_hly/od/delborder_od.html

https://athene.as.arizona.edu/~fwildi/cars/tech_talk/overdrive_frame.htm

https://www.ntahc.org./techtips/OVERDRIVE1.html
D

 

[canuck]

Thanks for your help. I have printed out and am reading all the recommended materials, but done nothing yet but check oil and pressure, both fine.

Time, not ingratitude, the reason I haven't responded...I'll let you know the results.

Canuck

 

[canuck]

Well, sadly, it is not the solenoid or operating valve. Pressure tests fine too. After reading all the threads and links I printed off the man who owns the garage brought a guy out of retirement who used to be THE go-to guy for all brit cars around here, had many Healey customers, and still drives around in a '67 E-type. This esteemed gentleman identified problems with the overdrive clutches, and a search began for the parts. No one seems to have these, so the solution is to rebuild the overdrive unit (this baffles me...how can you rebuild it if the parts aren't all available). A local parts supplier (mostly a Moss dealer I think) offers a rebuild kit. I am told that the rebuild, installed, will set me back $4,000 Canadian (around $3,000 US now), and involves engine removal among other things.

I do not believe these guys would deliberately take me down a path where I would spend more than necessary to do the job well...but naturally this news does not thrill me.

I note that British Car Specialists will do a rebuild for $450 US ($600 Canadian) plus parts...but that would involve removing the O/D, shipping it from Canada to California and back, reinstalling it, all presumably without use of the car for some time.

I don't imagine this is a Haynes one spanner job, which given that I have never done more than an oil change, plugs and points on any car and own no tools is probably my limit, so I think unless I want to take a course, spend a ton on hoists and tools, do without the car for ages, and take a lot of chances, I'm into writing cheques as a repair process at this stage.

Before I give the go ahead, does anyone have any thoughts? Is it possible to buy a rebuilt overdrive with exchange, for example? Are there other suppliers who might have the overdrive parts Moss doesn't, and whom the three or four brit car garages my guy has checked with would possibly not have tried. (This guy has a huge network, and I think he worked it pretty hard).

For a brief moment, I contemplated a Toyota truck 5 speed...apparently a ton cheaper, and then no hassles, but the authenticity aspect is too important to me. I would use modern starters and fuel pumps, but the overdrive seems to me part of the experience of driving the car, so I'm inclined to hang on on this point.

Thanks in advance for any help anyone can give.

Canuck

 

[Dave Russell]

Canuck,

Sorry that it wasn't an easy fix. If you have someone that you trust to do the rebuild you may be able to find the parts. You didn't say if it was the "clutch sliding member" which has linings on both sides, or the unidirectional clutch (Sprague) or both.
Standard OD rebuild kits do not contain the clutches.

I checked my catalogs & found the following;

Victoria British - 1-800-255-0088
#2-7223-Z - Sliding member with linings - $200 + $60 core
#2-3022 - Inner member clutch (Sprague) - $130

SC parts group UK - www.scparts.co.uk
#SC1903 - Clutch sliding member with linings
#SC1917 - Inner member (Sprague)

Hemphill Healey Haven - 1-800-943-2539
#ODR-119 - Sliding clutch member - $190 + core
#ODR-127 - unidirectional clutch - $125

British Car Specialists - 209-948-8767
#COVD 107 - Sliding clutch -$200 + core

If you don't have anyone local to do the rebuild;
Cape International - www.cape-international.com
Offers rebuilt OD assemblies exchange for 400 - 500 pounds uk

I suspect that a couple other of the above sources might sell a rebuilt OD on an exchange basis. Check them out. You would still need someone to install the new OD assembly.

I believe that the OD can be removed without removing the engine if you know what you are doing.
D

[ 06-19-2003: Message edited by: Dave Russell ]</p>

 

[Healey 100]

Canuck:

I think British Car Specialists rebuild price of $450 plus parts is very reasonable. I'll bet they could turn it around pretty quick. I think your unit has some sort of a problem with the pistons, linkage and bar that move the clutch. I have not seen much wear in these clutches, somehow I don't think a warn clutch is the problem. But you can't find out without removing the OD and looking inside.

I have removed my BN1 OD without taking out the engine. I did take out the transmission. An experienced mechanic could probably remove the transmission with about 2 hours labor or less, especially if you did some of the prep, like removing the carpets, seats, etc. Taking the OD off would add another hour or so. Putting it back on is MUCH harder! It can be difficult to allign all the bits and pieces in there and get the pump up on the cam properly. I think I might consider shipping the transmission and OD to a competent shop and let them handle the removal and replacement of the OD along with any rebuild.

There are a number of other places that would probably look at it as well and would be willing to work on the transmission/OD assembly if you shipped it to them. Isn't it cold up there in Canada? You could sent it in the middle of one of those cold, long winters!

Good luck

 

[canuck]

Thanks, Dave and Healey 100...I'm going to continue the research. Cape's rebuilt can be obtained with a deposit, refundable when the unit is returned, so that would allow me to keep the car on the road throughout...you are right about the winter, and I am now thinking about living without the overdrive (staying away from highways) for the summer and having the work done over the winter.

If I do have to have the engine out, I'm wondering if it would make sense to consider having that rebuilt at the same time....given that we have four months of no driving anyway, and while I have my cheque book out.... My engine has a theoretical 85,000 miles on it...any experience on what the typical life between rebuilds is? And what should that cost to have done?

Thanks,

Canuck

 

[Dave Russell]

Canuck,

In addition to Cape, check with some of the others about such an arrangement stateside. Another possibility for help is "Precision Sportscar" located in Richmond Hill, Ontario, CA. Mike Salter is one of the best & it would be close to you. Just explain what you want to do & see what he says. I would not hesitate to follow his advice.
https://www.precisionsportscar.com/

If you wish, the transmission/OD assembly can definitely be removed without removing the engine. Also the OD only, can be removed from the transmission while it is still in the car. The hard part comes when trying to get the OD back onto the transmission. It takes some "educated feel" to get the internal splines & oil pump drive cam, & unidirectional clutch aligned properly. I don't know if you have a factory shop manual for the car, it would be very helpful at this time for both you & the mechanic. Available from one of the above sources.

I don't see where you have mentioned what model you actually have but 85000 miles is not excessive for a well maintained engine. It could last many more miles before needing a rebuild. If evaluation with compression & differential pressure tests (leakdown) show things to be reasonable & oil consumption & oil pressure, etc. is reasonable You shoulden't need a overhaul yet. However if you just want the fun & assurance of a new engine, it would be easier to do the transmission with the engine out.

My 100-4 has 85000 on it. The bottom end is just as tight & trouble free as when new. The valves were bad & I did replace the top end with new improved parts. Compression is an even 140 & leakdown is less than 5% with the new head. Oil consumption is about 1 qt per 2000 miles.

I must stress that the success of the project depends very much upon the knowledge/capability/integrity of the mechanic who is doing the work. Select carefully.
D

[ 06-21-2003: Message edited by: Dave Russell ]</p>

 

[wally stokes]

Canuck I am new to the forum and have not introduced my self yet but reading your problems I am sure they can be solved in canada,Have you tried the auto farm autofarm@gate-way.net or the person who did mine would be interested as you are onley one hour from here

 

[ThomP]

Some observations:

Healey engine removal takes about 8 hours if you have the right equipment. Replacement is another 8. This does not include stripping the trannie from the engine or removing the OD unit. At the going rate (let's say 50/ hr) we are 800 toward that 3K figure. and we haven't looked at the OD yet or purchased any parts. 3k to have someone else do the job is probably a reasonable figure.

I have been told that the transmission can be removed from the car without removing the engine. The interior needs to be emptied, but It'll come out through the passenger compartment.

If you enjoy doing this kind of task or, at least, don't mind, you could save some $$$ and afford to do a better job, just don't expect it to be a 16 hour task for someone that does it once in a while.

My BJ8 engine was smoking "4 packs" a day at 70,000 miles, but I don't beleive it lead a charmed life prior to me, if you know what I mean. Realistically, 100,000 miles on an old 6 like the Healey is a ripe old age. If your car is known to be well looked after all of its life you could expect to get those 15,000 miles (or more) without any serious problems. Ask youself: how long will 15,000 miles last me before I have to pull this @#*& engine again right after it is out and on the floor for the OD work. The answer at that moment should guide you better than any of us. BTW to have someone else rebuild a Big Healey engine here in Florida is about $3800 and 50 hours of work (The agreed rate was slightly lower than mentioned above). Parts including new pistons and Machine work was about $1800.00

British Car Specialists have a great reputation.

Good luck in whatever direction you choose

 

[tahoe healey]

I don't see any reason for not driving with out the overdrive. The engine just revs faster but no harm. Just poorer gas milage. Just check another recent post regarding rpm to mph. Think of how fast you'd have to go to get to redline in forth.

 

[canuck]

This is great information everyone. First, I have found autofarm since I got going on this. They are about two hours from me. Thanks Wally...where do you live...you can send me a private message. Precision is a little closer, I was aware of them and my mechanic has been speaking to them. Second, the comments about having the engine rebuilt at the same time make sense to me...my plan has been to have the car be a daily driver in the summer, avoiding rainy days where possible, and I want to get it reliable enough for some touring and weekend trips. I figure that is 5,000 or more miles a year, maybe more if I am confident enough to go farther afield. I haven't done enough driving to gauge oil use, but I had the oil changed when I got it, and have put in a quart after about 350 miles. So logically, I should run it this summer without doing anything, and then make the judgement when the car has to go away anyway, but it's looking like I should save my money for a big winter investment.

Third, as far as driving the car without the overdrive...sure seems loud and high revving at the 70 mph which is the low end of highway speeds around here. The speed limit is 100kmh, about 63, but the reality is more like 75 to 80 if you are keeping up with traffic. Not comfortable on a sustained basis without the OD. And gas mileage is brutal...I have been getting about 9 miles to the gallon as far as I can tell...what is normal anyone? Plus even high revs below the redline would wear the engine more wouldn't they?

Again, thanks to all for your help...I have a lot to be going on with.

Canuck

 

[Dave Russell]

Canuck,
The hardest part is making the decision on what to do & where to do it. Second hardest is finding the money, but with the first decision made, you will be forced to find the money.

With the high oil consumption & low gas mileage that you describe it sounds like time to do the whole works. I doubt if it will be reliable enough for touring & weekend trips without some serious overhaul. Nothing worse than getting stranded everytime you try to go somewhere. The average Healey should get somewhere between 18-22 miles per US gallon as an average. The overdrive out would not reduce this more than about four mpg.

Good luck,
D

 

[ThomP]

My BJ8 gets an exceptional 27 to 28 MPG on the highway and 14 to 15 around town. I guess that averages to the 18 to 22 mentioned above.

If you're only getting 9 MPG check that the carb floats are'nt sticking or clogged with stuff from the fuel system and being held open during operation. If there is "stuff" in the bottom of the fuel bowl, then it is probably interfering with the needle valve seal prior to settling in the bowl.

 

[John Turney]

Canuck,

Just a comment. The engine doesn't need to come out to remove the OD. The trans and OD are removed together out the top. (I've done it myself as has British Car Specialists).

John, BN4

 

[RF Thom]

Try John Esposito @ Quantum Mechanics. I've found him extremely knowledable and he has all the parts to rebuild the unit - even some parts which Moss etc show but identify as N/A. John can be reached at quantumechan@earthlink.net. He is also close Monroe CT. 203 459-9612.

Regards, Bob

 

[canuck]

Thanks again. My assessment of the input from the forum and in talking with a couple of mechanics is that you can do the OD without taking out the engine, but it is easier to take it out as putting it back is tough, as it has to be done blind. Further consensus is that the car is not designed to hum along steadily at 60 plus without the overdrive when it has the OD gear ratios in the trans...tough on the engine.

Given my doubts about the engine, it doesn't make sense, therefore, to do the OD and then find out I need to do the motor.

The net result is that I am going to drive the car easily over the summer, no long trips, avoid freeways but try to put some miles on at 50-60. This will let me monitor oil consumption and gas mileage, adjust carbs, find any other little things that could be a problem. Then I will put the car somewhere for winter where they can remove and ship the OD, maybe the tranny, and maybe the engine, and put it back together for me by next spring.

Thanks again for all your input. Reading your replies and those of others on other threads continues to be a great learning experience for me. Thanks in particular to Dave Russell...you obviously really know your stuff. I had never considered Boise Idaho as a possible vacation destination, but I do now. One of my major suppliers, HP printing and imaging, is there, but I have never gone. Now I have an important reason. Priorities!

Chris