Clutch noise?

[gmack]

I'm stumped. My 69 spider was mechanically rebuilt by an old master and then sat for nearly 8 years before I bought it, installed the interior, cosmetics, redid brakes, etc. I pr flushed all fluids and rechecked all mechanical specs, reset cams, all timing, etc. It has a euro style Weber conversion with proper manifold and intake box.

This spring the car starts immediately, idles right where it should and drives beautifully.

However, once fully up to temp, at idle to about 1400 rpm, I have a low frequency rumble, almost grumble, that ties to engine speed. (This is not present at first when the drivetrain is cold.) When I rev, the rumble goes away. The clutch works well but engages near the end of the stroke.

As soon as I engage the clutch, the sound is gone as well.

Everything else works as it should. The starter engages and disengages properly...no loose parts I can locate.

I very much appreciate your suggestions.

Thank you.

GMack
69 Spider
74 GTV

[ghnl]

Just some guesses here as I don't know the early models well (but I do like 'em...).

The exhaust system could be touching somewhere. Might just need a hanger re-positioned. Does it happen even with the gearbox in neutral?

Is there any adjustment for clutch pedal travel? In the later models ('hanging pedals') the clutch master cylinder's actuating rod is supposed to be set to a specified length. If that is not done, it'll affect the position where the clutch engages. Also, the clutch pivot shaft's weld can shear. Does your '69 have the floor mounted pedals?

[vf31rhill]

Don't like to sugggest expensive solutions, but you have to keep in mind that when the clutch is out at idle, and the trans is in neutral, the imput shaft bearing and the layshaft bearings are turning at engine speed. Since they are not transmitting power through the gear train in this configuration, any slack in any of the bearings (input shaft bearing and all the layshaft bearings) can show up. If the trans fluid is cold, it is thicker than after it warms up and thins out. So it may mask any bearing slack when cold. After you engauge the trans gears under load, the slack either is taken up or is masked by other trans noises.

I would check the trans fluid for correct type of fluid and proper lever to see if this affeacts the situation any. If I am correct (and I hope for your sake I am not) you will have to pull the trans and replace any bearings or possibly the laygear shaft to correct the problem. If I am correct, continueing to run the trans will only make the possibility of more serious damage to the gears greater.
Best of luck, and I hope I am incorrect on this, Robert

[papajam]

Quote:

Originally Posted by gmack As soon as I engage the clutch, the sound is gone as well.

[gmack]

papajam,

Sound goes away when I engage into gear. The drivetrain functions and sounds as it should given what i can hear once underway. When in neutral, clutch in or out, the sound remains.

Thanks in advance for your feedback.

Gmack