Can't solve my 1500HL problem

[alangraham]

I've got a problem with my 1500HL that I can't solve - been trying for ages, tried everything I can think of.
It's my 1500HL. And its a noise/drone/vibration. It's that noise you get when you've changed up too early and haven't got enough revs going.
Except that I change up at the right time, and the only way I can compensate for it is to speed up too much in second before going in to third. Because that's where it's evident, though to a lesser degree from 3rd to 4th. It's a noise that makes you grimace and it goes through the whole car, fading away as revs and speed increase.
You might reasonably ask: when & how did it start?
And the answer is I can't say, because I had so many jobs done at the same time that I don't know what made it start.
Here's what might be a clue:
It's awful after cold starting, and gets better when the engine's warmed up.
Here's what I've tried:
New main bearings,
O/D gearbox and new diff via Mike Papworth
New UJs at all ends
Propshaft balanced
New engine mountings and new gearbox mounting
Confirmed that gearbox mounting is right way up (via photos on this forum)
100% polybushed throughout
About the only thing I haven't replaced is the centre bearing prop shaft carrier but none of the fitters who've worked on the car have made any comment about that. I just feel that if I changed that too, it would make no difference because nothing does.
I'd really value anybodys suggestions that I can put to the trade, because I'm absolutely stuck. Ask me anything you want.
Thanks
Alan

[tony g]

Does the vibration only happen when accelerating ?
Does it do it if you dip the clutch?
Does it do it on overrun whilst slowing?
Are the compression pressures similar on all cylinders? (thinking here is a cylinder not working well at slow engine speed ie valve burnt/leaking)

Tony

[alangraham]

[quote="tony g" post
Does the vibration only happen when accelerating ?
Does it do it if you dip the clutch?
Does it do it on overrun whilst slowing?
Are the compression pressures similar on all cylinders? (thinking here is a cylinder not working well at slow engine speed ie valve burnt/leaking)

Tony
[/quote]

Yes, only when accelerating.
Dipping the clutch will stop it.
Doesn't do it on the overrun whilst slowing
Compression pressures currently unknown.
Alan

[tony g]

If ramp access is easy for you,I would look at the height of the rear of the gearbox relative to body. If the tail of the box is too high or too low the prop u/j's can go into a bad angle. Typically the rear of the box will lift and twist slightly when torque is applied. A quick check/test is to put a couple of washers between the body and gearbox crossmember to lower the box slightly. Try the car out. If better its to do with mounts being wrong angle or height. If worse it may need lifting up which is hard to do unless the mount to crossmember can be tweaked. Engine mounts can have a lesser effect too, new doesnt mean good of course.
Dont know about OHV so much as slants but is the steering rack anywhere near the engine? Torque makes the engine dip towards driver side so any contact from engine to body(rack) can promote a lot of noise and vibe.

HTH

Tony

[grahamwatson]

Have you seen this thread? viewtopic.php?f=4&t=32621

Your vibration sounds like it is more severe than would be caused by the propshaft being out of phase, but it does sound as if it is transmission related so may be worth a check.

[Magenta Auto Sprint]

where are you based?

Malc

[alangraham]

Graham, I hadn't seen that topic; I find it very interesting and useful thank you.
Malc: On the A684 between Bedale and Leyburn. 10 mins from Leeming Jct on A1.
Alan

[alangraham]

I've got an inspection pit in my garage so I went down this afternoon and took some pictures
Alan:

[Mahesh]

Only looking at the pics, could be the angle,

is the prop low on the centre bearing, the rubber looks compressed lower down.

[Richard the old one]

My error I thought you were missing the exhaust bracket from the gearbox /Overdrive joint but having looked again I can see you have got something.

[grahamwatson]

Your propshaft is out of phase if I am understanding the pictures correctly. I am assuming that your second and fourth pics are of the front UJ, and the fifth pic is of the rear UJ. Also that you did not roll the car backwards or forwards between taking these pics.

If all of that is correct, the front yoke of the front UJ is lying east/west (ish), but the front yoke of the rear UJ is lying north/south (ish). Does that make sense?

If so, and you confirm that is indeed the case, the propshaft needs to be separated at the central spline, and reinserted on a different spline which will align the front and rear yokes, which puts them back in phase.

Also try and maintain any balance marks on the UJ flanges, where they connect to the gearbox at the front, and the diff at the back.

All of this may not resolve your problem, but it will eliminate one issue.

Hope this helps!

[alangraham]

My error I thought you were missing the exhaust bracket from the gearbox /Overdrive joint but having looked again I can see you have got something.

Yes Richard, we followed your written guidance and instructions from a few years back to convert this car to overdrive - making a great difference. As the original bracket (that you mention) was unobtainable, it wasn't hard to make one. The only part we couldn't source was the short 1500 O/D prop shaft but we heard from other club members that the existing one could acomodate the shortened length and indeed this seems to be the case; it's also been well greased.
Alan.

[alangraham]

Only looking at the pics, could be the angle,

is the prop low on the centre bearing, the rubber looks compressed lower down.

It's just the angle. Even with an inspection pit, getting an SLR camera in the best place isn't the easiest job.
Alan.

[grahamwatson]

Alan, did you see my post above after your pics? I think you were posting at the time so may have missed it.

Have you checked whether your propshaft is indeed out of phase? If you didn't move the car between the pics you are about 90 degrees out of phase, which I think would give the worst vibration. Certainly worth checking.

[tony g]

I thought the phase looked ok, bearing in mind clockwise view one side and anti the other ?

Tony