For quite a while now I've noticed around 2500rpm my whole car is vibrating, in any gear... everything rattles. It's a constant vibration - looking in the rear view mirror its vibrating so much that everything is blurred.

Once you accelerate over 2500rpm say to 3000rpm, the vibration changes to less of a constant thing, more like little bursts (about 80 per minute) of vibration.

When the car is stopped and clutch is in, you also get this vibration, so it cant be the transmission or drive shaft...

any ideas as to what this may be?

Cheers,

 

get your wheels balanced first. Then if its still there look at tailshaft balance, engine balance, anything that rotates.. get it balanced

-James

 

sorry, just read the rest of the thread.. you say its with clutch in aswell... so its got to be something to do with engine/clutch... possibly transmission but i doubt it.

Check your motor and g/box mounts, and get a friend to rev it while you watch the engine and see if the whole thing shakes like a bitch

-James

 

The whole thing shakes like a bitch! ... but the engine mounts are tight... maybe the rubber dampers have gone too hard? Still i reckon the engine isnt meant to shake like this - there must be something causing it to do this, what you think?

Cheers

 

its possible you have a bent driveshaft too, check that out

 

Driveshaft isnt spinning when the problem occurs...

 

Have you had the engine or transmission out of the car or is this something that has just developed on its own?

 

Just maybe...
Well, I've been scolded for saying this on this forum, before; however, it could very well be a mismatched flywheel / counterbalance weight. The SAs motor had a different flywheel than the newer FBs; with different weight stats. I had this issue upon an engine swap and flywheel swap. I still have my 1981 engine flywheel on the shelf, as well as the 1980. They are different.
I ended up purchasing a lightweight steel flywheel setup from Racing Beat, as since I had to go through the activity, it gave me an excuse to purchase the lightweight version and swap it.

 

Yeah, a rotary should be smooth as silk. My guess would be a clutch issue. Good luck!

 

Hmm, I havent changed anything since this started happening, well I just had a new muffler put on with a tiny outlet so I can pass roadworthy... This blew a hole in the cat, but that doesnt bother me and I dont think that would cause these vibrations? When the new muffler was put on, they did not take anything off the car, just cut off the old and welded some flanges on and bolter her up...

My clutch on the other hand is stuffed! It's been slipped to hell and back.. but this problem does occur when the clutch is in. The engine isn't running smooth... you see the whole bonnet vibrate and the engine jumps randomly to the side a little... This could be a different issue... or the same, im not sure..

 

im pretty sure sumtin is out of balance

 

mmm what sorts of things go out of balance on their own?

 

You check to see if you're having some intermediate ignition problems? Check your plugs for misfiring or if they're fouled out? Not firing somewhere can throw it out of balance, but i'm not sure to how much in your situation. Anways, always check the simple things first.

 

I thought of the same thing as GavinJuice.
What state is your ignition in?

Attach a timing light to the plugs,and have someone help you to keep the RPm at 2500.Maybe one of the plugs arent firing correctly.Otherwise there is a small chance that there could be electrical interference?

 

Do you have the stock fan clutch? Make sure it's on tightly. If it's loose, I can cause a hella vibration about 3000 rpms.

 

I checked all the connections between plugs and distributor, made sure they connected tight, then the connections from the coils to the cap - they too are now tight... regrounded everything in the engine bay I could find.... didn't make any difference...

The clutch is stock and is kinda on its way out, previous owner did some serious slippage. I'll look at replacing that ~3 months. Can't afford to yet heh..

Have to get back to you about the timing light tomorrow.. Raining at the moment... Thanks for the tips so far.

 

I just started her up before (about 9:30pm) after sitting outside for about 8 hours without running.... and its reasonably cold... and she started fast and idled silky smooth.... What the hell is going on?

It's never been this smooth! Ever! I liked it, but after giving it some gas, it was rough holding it on, then after letting it off, it didnt idle as smooth...

Today I did a lot of little fixes to the car:
- rear wiper contact points
- secured loose relay near battery
- secured loose wires in the engine bay
- taped up bare loose wires in engine bay
- lubricated all the moving parts on the EFI unit to do with throttle
- bolted oil cooler on (was attached with cable ties)
- lubricated driver door lock
- taped up loose unknown wires in drivers door
- regrounded a few connections
- tightened quite a few loose bolts

I think thats about it... I'm guessing it may have had something to do with lubricating all the moving parts of the throttle? It wasn't proper lubrication, just sprayed it with RP7/WD40... so .. can anyone guess why it ran so smooth? I'm betting it's related to my vibration problems, because it was incredibly smooth! nothing vibrated at all. unbelievable...

Cheerio

 

So the cars vibration problem is sorted?

If not my guess is an ignition problem, beyond plugs, coils, leads whathaveu, ignitors seem to be the culprit of unexplained and sudden onset vibration - Does the car miss when idleing?

good luck Sue

 

Well this occurrence explained above was once off.

The car is still vibrating as it was before. I will look at getting new ignitors. The car does miss when idling.. quite a bit actually..

Cheers

 

Did you ever fix this issue? I have a Points based Distributor on a 79 that is having a similar issue (Vibration that peaks between 2500 and 3000) and I think that I may be getting arcing on the dis... The Vac. Advance for the Trailing is hosed...?

 

It was the gearbox mount

 

LOL, re-reading this thread after a year has gone by was pretty funny. I was about to suggest that your new exhaust was coming into contact with a frame rail or something. Glad you got it sorted out.

 

hehe damn it has been a year! crazy

yea my original exhaust (aftermarket custom job) had been welded to the old gearbox mount.. this both wrecked the mount and sent more vibration thru the chassis. We cut that mount, have since overhauled the entire exhaust hehe, new reso and new muff and a new gearbox mount... even a new gearbox lol :P

she was running sweet til some idiot crashed into me tho (well she still runs just doesnt drive)









drivers door dented in as well :/ bit of a mess, should be fixed by the end of the month

 

Wow, that's gotta hurt. Hope you get her back good as new.