• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

running out of revs

Share this page

C

ceedub

Senior Member
Country flag
Offline
I am experiencing something new and hope someone can help. At idle, after the clutch is fully depressed, the rpm's slowly diminish. After a few seconds, I'm down to 500rpm and then it is a rapid decline to stall. Otherwise, the car runs great. Could it be a mixture issue? I'm stumped.
 
Are we talking about a 73? Is the car in stock configuration, or does it have a Weber on it? Tell us a little more about what has been done to the engine, if anything. PJ
 
hi ceedub,I'll throw my 2 cents worth at ya.I don't know why pushing the clutch in would make a difference in the idle speed other than to mabey change the load on the engine from the throwout bearing and clutch releasing etc, but I'm guessing you have hif4 carbs? With stock air filters as opposed to aftermarket ones?
Have you checked for vacuum leaks on the intake manifold (rubber caps missing etc)and rubber hoses coming off there?(splits etc) Will it sustain an idle if you don't touch the clutch?
I've had my 74 with HIF4's pop on startup and blow a cap off my intake manifold ,If you are totally stock , you may not have any of the ports capped off on your intake manifold as I do though. Look for uncapped ports on the intake manifold and cracked hoses. Hope this helps a bit..Good luck. Mark
 
Thanks for your input, Mark. The car idles well with the clutch out but depressing it causes the problem. I'll have a good look at the manifold for leaks and see what happens. Cheers,

Ceedub
 
Since this JUST happened to me, I'll toss in my 2 cents. Short version is that my throwout bearing died and now when I push in the clutch, the RPMs drop and the car will stall if I don't encourage it with a touch to the gas pedal. You may have a similar situation happening.........
 
Were the clutch and throwout replaced as part of the rebuild?? A similiar incident years ago for me was a failing throwout where the center carbon surface was breaking up causing increased friction against the pressure plate.
 
Check the crankshaft end play. You may have failing thrust washers on the crank. Pushing the clutch loads the crank and poor washers/bearings will cause the engine to slow down.

Search the archives for info on checking crank end play. TR6 have this problem.
 
The clutch assembly was replaced but I can't remember whether the throwout bearing was also replaced unless it was part of the clutch assembly. I remember that it required some loosing up so maybe it has seized up again. Thanks for the reply.

Ceedub
 
Thanks for the reply, Peter. I wondered about the throwout bearing. It certainly passed inspection when we did the rebuild last year. I hate to think that the fix involves removing the whole engine/trans again. If that IS the problem, I guess I have no option.

Ceedub
 
ceedub said:
Thanks for the reply, Peter. I wondered about the throwout bearing. It certainly passed inspection when we did the rebuild last year. I hate to think that the fix involves removing the whole engine/trans again. If that IS the problem, I guess I have no option.

Ceedub
Click to expand...
That's where I'm at.....universe willing I can get to it this long weekend. I've got all the parts...just need the hours.....
 
All good advice but always do the simple things first. Be sure the mixture is not too rich. Does it start without the choke? If you are right there on that fine line the extra drag from the release bearing may just be enough to start dropping the revs enough for the engine to start dying. I would think if everything was good a little while back when it was rebuilt then you should be fine as far as the release bearing. Good luck with the repair! Bob
 
Back
Top