13 replies to this topic

[tj_herron]

Hi all,

 

I'm looking for some advice as I'm struggling to diagnose an issue.

 

I have a 1978 1275GT that has been dry stored for the past 2 years. This week I have serviced the fluids, plugs, etc. to get it ready to go for summer. I took it out for a 30 minute drive which was going perfectly until it started to get a very noticeable judder when accelerating. This comes through the whole car and almost feels like the engine. You can feel it though the steering wheel as well. It's most noticeable in 3rd and 4th to the point that it becomes undrivable. The car shook so badly the exhaust centre pipe came lose and fell from the car. Thankfully it wasn't damaged and retrieved it and limped home.

 

So far I have checked the mounts which all look fine. There is ever so slight movement in the engine when I rock it but it doesn't seem anywhere near bad enough to cause the amount of violent juddering I felt. Oil level is fine and the plugs look good.

 

All I can think of is possibly timing, fuel mixture or worst case, the clutch going. All seem unlikely though as the car was fine for around 20-30 minutes of driving.

 

Does anyone have any ideas at all?

 

Thanks

[sonscar]

Is is accompanied by any noises?drivetrains related?driveshaft failing?Just a few thoughts,Steve..

[Spherix]

I assume it drive without issues before being parked 2 years ago then? Would you say it's only felt in third or fourth gear, or is it similar on different RPM's in first and second?

Have you checked if there is any oil leaking from the bottom of the clutch/flywheel housing? The level of viilence you describe would make me think of a loose flywheel, but that would end things pretty quickly.

Edited by Spherix, 11 June 2022 - 07:43 AM.

[tj_herron]

No more oil than would be expected. The usual small drips but nothing out of the ordinary.
It’s smooth at idle and once you lift off the accelerator the shuddering goes immediately.

[tj_herron]

It is very light through 1st and 2nd and then becomes violent in 3rd and 4th. Anything over 20mph.

It drove smoothly for years before this.

[Spherix]

No more oil than would be expected. The usual small drips but nothing out of the ordinary.
It’s smooth at idle and once you lift off the accelerator the shuddering goes immediately.

There should be no oil at all coming out of the small hole in the bellhousing. The reason Im asking because it does not sound unlikely that the clutch/crank seal has gone and is therefore allowing oil from the transfer case get on the flywheel and clutch.

[tj_herron]

That’s sounds like it may be the issue then. There is a small amount of oil there. It may be from the sump as I have a small leak there too, but I’ll wipe it down and take it out for a run gentle 5 minute run and re-check.
Any idea how difficult it is to change the seal? Is that a fix if I clean it all out or will it need a totally new clutch, etc.?

[sonscar]

Cannot see how a failed seal can do anything other than leak oil?If it got on the clutch it may cause it to slip or judder on take up but not when in gear.Driveshaft or diff?As mentioned a loose flywheel would soon develop.A methodical inspection would be my first choice before I would consider dismantling anything.Just my years of running old chod with no money here Steve..

[bpirie1000]

I would say replace the top engine steady bushes first. If there is any movement on these then things develop.. (roadside repair i have done before is wrap the bush in electrical tape pack out the bush) stopped the bump and bangs, short term repair though..

Is the clutch slipping at all?

I would also suggest jacking the engine via a block of wood and inspect the bottom engine mounts under radiator and under bell housing...

Eitherway... enjoy quality time with your car....

[tj_herron]

Thanks for all the suggestions folks. I’m going to get it up on Jack stands tomorrow and I’ll report back. This one feels like a needle in a haystack scenario. I’ve always been pretty good with a gut feeling about what it could be but this one has me.
Something with the clutch or driveshaft seem to be most likely because of the constant juddering rather than engine mounts but you never know

[Spherix]

Thanks for all the suggestions folks. I’m going to get it up on Jack stands tomorrow and I’ll report back. This one feels like a needle in a haystack scenario. I’ve always been pretty good with a gut feeling about what it could be but this one has me.
Something with the clutch or driveshaft seem to be most likely because of the constant juddering rather than engine mounts but you never know

 

In your earlier post you mentioned it was only happening when accelerating, here you write that it's constant. Which is it ? It becomes hard to diagnose over the internet if the symptoms are varying.

[sonscar]

If you drive it long enough it will"develop" as one of my old workshop managers was fond of saying.Of course this could turn a cheap fix into one that was less so.
A problem with internet diagnosis is that one persons idea of "its OK" may not be the same as another persons" it is sub optimal"No aspersions cast here,Steve..

[tj_herron]

Spherix, it is only when accelerating. At idle or when you let off the accelerator the car runs smoothly. Bad wording in my reply… apologies for the confusion.

[andyapanel]

If it was my car, I would be suspicious of the wheels. Are the nuts tight? Any obviously missing weights?

My second place to look would be the HT. I have had rotor arms fail VERY soon after servicing.

Good luck and keep us posted on progress