The 'E' Type Forum

Have just pulled out of my MOT station with a supposed clean bill of health - a little play visually evident on both rear wheel bearings and wonder if this is the norm? - certainly the tester felt there should be a little slack but in fairness he is no etype expert - would welcome others thoughts?

This time of year is really special with all the new blossom, warmer temperatures, dry roads and of course being lucky to drive the etype. One of the things that provides great satisfaction in bringing this car back to life after so little use in the preceding 35 years is that all areas of the car have and are needing attention to bring them back to specification and slowly slowly each action brings an improved result and the payback of getting to know and understand the ins and outs of this lovely car.

There seems plenty of go from the engine with the massive improvement that the overhauled distributor has endowed but this is now showing up a slight vibration in the drivetrain (not wheel balancing) and at 3500rpm, when under load one can increasingly feel the discontent and if I let off the throttle it is less evident and by driving through to around 4200rpm it tends to smooth out.

My question is whether others might also point a finger at the driveshaft UJ's although there is no evident sloppiness. The wheel bearings? although I would have thought they would be noisy rather than show up a vibration?

If it is throttle sensitive, my first suspicion would be prop shaft, either worn or seized UJs or, just possibly , out of balance. If the drive shafts couplings were worn, I would expect that you would be able to hear a clunk on each load reversal

I have also found that it is very difficult to be sure that it is not wheel balance, particularly if the imbalance is on a rear wheel

Does it disappear if , at the road speed where it is occurring , you declutch/put in neutral and then reappear if you rev the engine to 3500 rpm ? And is it the same in every gear at 3500 rpm? If so, this points more to engine than transmission and suggests that a check of the crank damper is worthwhile

Good points Chris, I'll test as you have suggested. Don't believe it to be wheel balance, the tyres and rear wheel rims are new (not infallible of course).

The crankshaft damper is a new one replaced last Autumn, but what to do if it is the cd?

Chris

Just come across an old post from Viper and at that time there was some discussion about MWS wheels - so will also jack the car up and check the rims are in the round!!!

Prop shaft imbalance or worn u/I'd will happen at the same mph rather than rpm so you diagnose by changing gear. Wheel imbalance is usually detected by vibration in the steering wheel at a particular road speed. As others have pointed out it could be wheel imbalance, wire wheels out of true, repro hubs or, and this is my favourite, repro spinners which do not tighten up properly because they are basically crap (thank you Orson Engineering and SC Parts who IMHO should be reported to Jaguar for abuse of their logo). If you have repro spinners put a set of gnarled originals on and see what happens.

There seems to be an odd combination of original/repro spinners, wheels and hubs that causes problems.

richard btype wrote: little play visually evident on both rear wheel bearings and wonder if this is the norm? -

Yes there should be discernible play if you have the correct spacer shim.

Thankyou all, will check out further and report back...

So a clear road this evening and checked in various gears, the 'coarseness' is coming in at the 3500 rpm, dip the clutch and the whole car is smooth no vibration through the pants or steering. I'm wondering whether it could be the crankshaft damper (replaced last autumn) or whether poor timing could cause some imbalance?

So if it's happening at the same RPM regardless of gear or road speed that leaves you with the engine and ancillaries. What led you to replace the balancer in the first place? I would doubt it's timing or tune if it gets better again higher in the rev range.
WRT wheel balance (probably not your problem). Most retail tyre suppliers can't balance wires properly because they don't have the correct cones to hold the wheels in the machine. I have had brand new wheels and tyres come back to me miles out on balance. When correctly set up by someone who has the right equipment and knows what they're doing the wheels come back perfect.

Andrew

Definitely not out of balance wheels, the only thing that makes sense is the crankshaft damper and I changed it last autumn due to noticing that the rubber was starting to delaminate from the metal plate.

I guess a replacement is the only answer to see if that makes the difference.....

richard btype wrote:Andrew

Definitely not out of balance wheels, the only thing that makes sense is the crankshaft damper and I changed it last autumn due to noticing that the rubber was starting to delaminate from the metal plate.

I guess a replacement is the only answer to see if that makes the difference.....

I guess it's worth having a look at the water pump and pulley, the alternator and the fan belt tensioner as well. If you still have your old harmonic balancer try putting it back on and see if it changes anything.
The only other thing I can think of offhand is the clutch.

I can confirm that I had these exact symptoms and I replaced the Prop

Sorted and very pleased

"Replaced the prop"..?
Are new ones available and good?
What about sending the prop off for balancing, with new UJs? Even though the old weight is still in place and the arrows align (when the prop has two halves as on the Mk10 where I have this problem)