E-Type perfection, 5 speed and harmonic balancer

(melloyello) #1

A guy I know invited me to his shop today to look at a series l FHC he is restoring, he also asked the owner of the E to stop by. Spent 3 hours trading stories and learned a few things. This car was a very good example of a restored E but not good enough for this engineer owner. He required perfection and I am sure the finished product will be perfect. I give this guy credit because he will drive the wheels off this thing when complete, I would be afraid to.
I have been looking for a 5 speed transmission and don’t think I can hold out any longer for the JT5. This car will be getting “The Driven Man T5”. It is the Z spec whatever that means? Complete kit that requires no body modification. Would like to investigate further but have not been unable to get any feedback on this T5.
Learned from this engineer that the harmonic balancer from a big block Chevy will eliminate the resonance at high RPM of the XK engine, he said that is what XKs was selling? He said that this balancer was often used on a Mopar engine famous for breaking crankshafts at high RPMs and eliminated resonance and breaking.

(Erica Moss) #2

The Quaife 5 speed is supposed to slip in without body or drive shaft modifications and the exchange rate is pretty favorable. I emailed Mr C and got a sparsely worded response that implied to me that JT5s might not be available in the foreseeable future.


(Nick Saltarelli) #3

Now that’s interesting.

The 3.8s had a 5500 rpm redline and the 4.2s 5000 (except for the 1968 Series 1.5 open headlight variants that also featured a 5500 redline tach, though I suspect marketting may have managed to overrule engineering on that point). The reason was crank asymetry. So then, what would be the XKs’ adjusted redlines with their cranks mated to a big block Chevy harmonic balancer instead of the Metallastic damper?

(melloyello) #4

The Qualfe is a new one for me. Fth is .762 would prefer something around .63.


(melloyello) #5

No idea what the red line would be, just passing on info. He did say the resonance disappeared, up to what speed I will ask him next time.
Not even sure if resonance is the correct term? I remember driving in a tsd rally
in the 70s at constant 100 plus mph with a pickup on my tail. Engine drone high and low, not a pleasant sound.

(Nick Saltarelli) #6

There are XK engine experts in J-L who might set us straight. I’m still running my original 51 year old Metalastic damper. Maybe time for a change.

(Michael Rogers) #7

As I recall the E’s racing against Vetts determined that they MUST be able to hold together at 7000 to make the necessary power to win so went to a very light flywheel and heavy front damper–from a MK-10? dumping the power from the front cylinders into it rather than twisting the crank getting it to the rear.

(tony) #8

I know this is not auto engineering school, but there was a recent/current discussion on harmonic balancers and redlines on this forum.

I did ask a couple of questions following on from replacing 20yr old harmonic balancers on I6 engines that were shot, and some implications of engine/crankshaft harmonics for XK engines, which led me to do some more reading.

As far as I could tell, the problem for an XK is in the long crankshaft??
as an I6 motor apparently has balance in the 1st and 2nd harmonic

The Jaguar HB are obviously better than most…they last 50yrs, but rubber is rubber

I detected the bad HB by observing a slight “wobble” with motor running, and suspect rubber deterioration may mean the damper fails to do its job, or makes vibration worse…dont want to think about them separating at 4000rpm

(Ben E) #9

Did you get the impression there was an appetite to bring them back at some point?

From previous comments I’d seen on J-L, I had the impression the JT5 was gone for good…maybe I misinterpreted those comments.

(melloyello) #10

I have gotten the impression that gear availability was the problem with the JT5?
My assumption is that the gear sets are made by Tremec? I also assume the gear sets for a Tremec for a Mustang have different ratios? If you want ratios to match
the Jag box they must be custom made? by Tremec? There are 2 or 3 other Tremec Jag boxes out there that I know of. This is all guess work on my part and don’t believe answers will be found here. Also remember reading that the Tremec gears were not as strong as Jaguar parts yet Mustangs were higher HP?

(Ben E) #11

I doubt that Tremec is making anything that is specific to the gearboxes being adapted for use in Jaguars. The Tremec gearbox serves as the basis for the conversion, and any parts that are needed to make the gearbox fit in an E-type are likely being made in the aftermarket.

It’s surprising to hear that there have been such significant supply issues for the Jag conversions, when they should be able to put such a $$ premium on them. Modern Drivelines recently tooled up to cast a unique tailhousing and innards that allow you to bolt a Tremec T5 into a Ford Falcon…a Falcon, for God’s sake!

As for the strength of a Tremec T5, a “World Class” T5 is generally considered about a 300 hp transmission. Having said that, I’ve been putting well over 300 hp through one for many years in a light car, with some “mechanical sympathy” in how I shift gears. I can’t imagine a Tremec T5 breaking a sweat in an E-type, unless the parts needed for Jaguar applications somehow lowers the horsepower rating significantly.

(Erica Moss) #12

Yes the parts aren’t available but there was no estimate of when that might resolve.

(Ben E) #13

I guess what I was getting at was whether their tone was “we’re working on it”, or “don’t hold your breath”?

(Erica Moss) #14

His exact statement was, " Currently I am not selling these transmissions due to parts shortages". To me that feels indeterminate.

(Phil.Dobson) #15

A subject on my mind just now is crankshaft dampers. When is a fluid type the right choice?

(Cedric Chew) #16

This is the same sentiment I perceived almost a year ago, which led me to stumble upon the group buy for the Broadsport gearbox. I was too late to join in but I did get a discount nonetheless. I haven’t installed it yet, but it will be replacing the original Moss box.

(Kevin) #17

It’s the same response I received a few months back.

So, I wonder what would happen if we offered a group buy from him? Would that suddenly cause parts to become available? It seems to me that perhaps he just doesn’t want to deal with this anymore? Can we change his mind? Do we want to try?

I wonder if anyone has measured the Mazda MX5 gearbox? I know that they can handle the HP/torque. Frontline Developments uses the MX5 six-speed in their Abingdon MG’s…mine had 300hp going through that MX5 box with no problems. I have no idea if they modify any of the gearbox internals to handle the power.

(Ben E) #18

My experience with the MX5 6-speed is that it may be too bulky, but also that the shifter will definitely be too far aft.

I honestly think the best bet for doing a 5-speed in an E-type with commonly available parts is to use the T5 that I mentioned earlier that Modern Drivelines has recently started producing for the Ford Falcon. The tailshaft is based around what Borg-Warner produced when the T5 was installed in the Chevy S-10 pickup, so it’s essentially an OEM configuration, and it puts the shifter in exactly the same place at the JT5.

Now yes, you’d have the tail housing protruding down the tunnel, making access to the front U-joint a problem, but I don’t think that’s insurmountable.

The the T5 is already a proven platform in the E-type, they’re designed for the power/weight of the car, they’ll be supported until the end of time, and all the belhousing/clutch adaptation for Jag/T5 has already been figured out.

(Eric) #19

I used an S10 T5 gearbox when I swapped a Stage 3 Buick V6 into an 80’s vintage Lotus Eclat. The original Ford based 5-speed in the car had dropped fifth gear and the miserable 4 cylinder engine was an insult to the chassis. Anyway, the S10 T5 was the only thing I could find to fit in the very small space. First gear was a “granny” so I used 2-5. Worked great given the prodigious torque from the Buick engine. I’d guess the new versions for the Falcon use a more suitable gear set.

EDIT: I just spoke with the owner of Modern driveline. He knows Paul at Meditronics and says he suppies some parts to Paul. One of the holdups for Meditronics (and Modern driveline) is the ,7X 5th gear. I believe he said the .6X is available. He (they) need an bulk order of about 200 gears to get a production run from their supplier. He did say he has stayed out of the Jaguar market as a professional courtesy to Paul. We then discussed the long tail shaft gearbox that he currently sells. It has a V8 gearset (3.0 first gear and .6X fifth). The overall length from the end of the input shaft to the end of the tail shaft 31.6 inches. Length from the end of the input shaft to the center of the transmission mount is 23.14". He says he can easily shorten the input shaft and the tail shaft about 1" (each) with machining and might be able to do more at the front end by substituting a different input shaft. He also mentioned that the 5-speed from the 2005-6 Mustang V6 might have some possibilities as the shifter location is in a forward location (we didn’t go into detail on that). I haven’t gone to the garage to take measurements on the old Moss sitting on the shelf, so can’t say if the V8 “Falcon” configuration would fit (lengthwise). I personally prefer a slip fit yoke, but clearance and access to get it started on the spline is obviously an issue. ( I should have asked him for length of the main case…)

The owner, Bruce, was very accommodating, seemed willing to look into fitment possibilities, and was extremely complimentary of Paul at Medatronics.

(Ben E) #20

My understanding is the S-10 tail housing has no effect on which gear sets can be installed in the trans, so you can use any combination of Mustang or Camaro ratios.

The nice thing about the Modern Drivelines re-make of that tail housing is that it allows for the use of a mechanical speedometer drive. I believe that was always a challenge when using OEM Borg Warner parts out of an S-10, and Mustang/Camaro internals.