My 68 roadster seems to run fine except that the RPMs are too high for the speed it is going. For instance at 5000 rpm it is only traveling at 80 mph. Has anyone experienced this or have an idea what is causing it.

Thanks

John

Submitted by cleavefamily@c… on Thu, 08/26/2004 - 01:23

There is an aluminum tag on the rear end that lists a number. I think the number is the reciprocal of the ratio: 1/ratio - If your tag is missing, one of the instrument repair houses (Nysogers (SP) or Palo Alto Speedometer) may be able to tell you what speedometer number goes with what ratio. IPL 5/2 lists the speedometer for the ratios by Jaguar Part Number not the Smiths number that's on the instrument.

Stew Cleave
JOCO Chief Judge
\'69 E-Type 2+2 and other LBC\'s

Submitted by john@trmiller.com on Wed, 08/25/2004 - 10:17

I believe the code on the speedometer will tell you what your rear end is, I found the codes for series 1 up to 1966 but have not found any for later cars. Does anyone know where these codes can be found?

Submitted by LazyMD@msn.com on Mon, 08/23/2004 - 20:42

I too have the same problem. I have a very early 68, built and bought in 67. My tach has not been calibrated, but I have checked it at lower RPM against my dwell/tach meter.It is accurate up to 2500 rpm. I did not go higher. At 70 MPH I have a tach reading of 4100. I have checked other mph vs. RPM relationships and they are linear. The clutch is not slipping. I wonder if they did not put a higher rear end ratio in snme of the early 11/2 cars.

I was talking about getting a 5 speed transmisson, but gave it up. How hard is it to change the rear end gear ratio? How do I check what ratio I have now? How do I change the Spedo if I change the rear end ratio?
Charles Peterson
68 E-type, Seattle

Submitted by jagboy69@hotmail.com on Sun, 08/01/2004 - 03:43

You would think that if the clutch is slipping it would be easy to figure out... 2nd or 3rd gear, stomp the gas// MPH doesnt go up.. SLipping clutch... Smell anything unusual??

Submitted by john@trmiller.com on Sat, 07/31/2004 - 20:01

At 70 MPH IT IS OVER 4,000 and at 40 mph it is at 2500 rpm, I called XK's unlimeted they also think it might be a slipping clutch. I am taking it in to Bassets this week, i'll let you know how I get on. Thanks everyone for your help.

John

Submitted by jrwalker@ev1.net on Fri, 07/30/2004 - 08:30

This is probably off base, but....................I am wondering if your clutch is slipping.

What is your RPM at a steady 40 mph on level ground?

Also do you have a dwell tach for engine tune ups? If so compare its readings to your tach at various RPMs.

Regards, John

Submitted by jagboy69@hotmail.com on Fri, 07/30/2004 - 01:39

John... you might check and see which rear end you have.. my guess is it's the 3.54.. You can solve this problem by going to the 3.09.

with the 3.54 at about 70mph, your tach should be in the neighborhood of 3100.. so you can imagine at 80 it probably sounds like the motor is screaming!!! Of course add some error in there for tach error too..

1969 Jaguar E-type(2+2)

Submitted by cleavefamily@c… on Wed, 07/28/2004 - 17:11

Is your tach calibrated? They degrade over time and need to be rebuilt; been there, doing that as we speak.

Stew Cleave
JOCO Chief Judge
\'69 E-Type 2+2 and other LBC\'s