Vibration increase, particularly at idle…any ideas?

[J liddy]

Hi I have had positive comments for running the D24 engines on 5W 40 fully synthetic oils .onwhat I'm told I have now gone over to this grade of oil on my D24

[AllHailKingVolvo]

No more progress on this from my end yet unfortunately, tested positive for Covid on Monday so have been stuck in my bedroom isolating from the Mrs and kids for the last four days! Would love to be tinkering with the derv instead, as they say you don’t know what you’ve got ‘til it’s gone!

[Laird Scooby]

Originally Posted by AllHailKingVolvo

No more progress on this from my end yet unfortunately, tested positive for Covid on Monday so have been stuck in my bedroom isolating from the Mrs and kids for the last four days! Would love to be tinkering with the derv instead, as they say you don’t know what you’ve got ‘til it’s gone!

Good luck recovering from the Kung Flu Phil!

[AllHailKingVolvo]

Originally Posted by Laird Scooby

Good luck recovering from the Kung Flu Phil!

Thanks Dave!! Out of isolation today so am planning to crack on and get the oil changed, and see if that improves matters!

[Laird Scooby]

Glad to hear you're out of isolation and that the Kung Flu was a false alarm Phil!

Hopefully the oil/filter change will bring about a recovery in your D24s running too!

[AllHailKingVolvo]

Originally Posted by Laird Scooby

Glad to hear you're out of isolation and that the Kung Flu was a false alarm Phil!

Hopefully the oil/filter change will bring about a recovery in your D24s running too!

Thanks Dave! It was my second go with Covid, the first at the start of last year which left me in a bit of a state. This time, despite the health probs I’ve had in the interim, it was nothing more than mild flu symptoms which were gone in a few days thankfully!

So, today I was finally able to crack on with the car…last year I found that the downpipe was rattling against the hoop clamp that mounts to the bellhousing, and solved it by wrapping some exhaust webbing around the pipe to act as damping. and tightening the clamp over it to hold it in place. I did suspect the vibration was down to that webbing deteriorating, and whilst it WAS deteriorating to the point of being mostly absent, remaking it with fresh webbing didn’t do away with the vibration. The engine felt rough, especially when warm, which confirmed to me that it was, as you said, likely oil related.

So out came the expensive fully synth, and in went some Q8 10w40 semi (not the most high end oil, but the garage I live next to had it on half price sale at £15 for 5L, I couldn’t turn it down!), along with a new filter.

Immediately it felt smoother and seemed happier, took it around the block and all seems to be well! There is still a slight vibration on an incline, but nowhere near what there was. I think this is down to the fact that when the rubber mounting hoops failed on the back box (the only support point on the entire system aft of the downpipe) I replaced them with fairly stiff rubber blocks which hold the system fairly firmly. As this is the only mounting point or damping point along the whole system, I think the blocks are transmitting some vibration through the floor of the car when stationary nose-up on an incline. Pointing downhill, there is barely any vibration at all.

I will seek out some hoops to put in place of the blocks as per the original setup, and see if it makes any appreciable difference to the last little bit of vibration. The oil seems to have sorted the rest of it, though, as you rightly predicted!

[Laird Scooby]

Good to hear the D24 is now running more smoothly again Phil!

Interesting about the lack of supports on yur exhaust system, this shows at least 4 rubber supports (two on each silencer) as well as the clip/bracket on the downpipe :

http://webcat.klarius.eu/cgi-bin/cat...no=960088&kid=

Not sure if that link will work, it should be to an image of the system in the Klarius catalogue.

Might be worth checking your middle box to make sure it has the bracket and rubbers present?

[AllHailKingVolvo]

Originally Posted by Laird Scooby

Good to hear the D24 is now running more smoothly again Phil!

Interesting about the lack of supports on yur exhaust system, this shows at least 4 rubber supports (two on each silencer) as well as the clip/bracket on the downpipe :

http://webcat.klarius.eu/cgi-bin/cat...no=960088&kid=

Not sure if that link will work, it should be to an image of the system in the Klarius catalogue.

Might be worth checking your middle box to make sure it has the bracket and rubbers present?

There is no middle box on my system! It’s a stainless custom system that was made for the PO, it’s essentially straight-piped bar one back box, hence the lack of supports midships-the rear box is the only thing that can have a hanger fitted to it!

It’s a noisy system, but not gratuitous. The back box has some baffles removed as part of the build and it’s throaty but not ridiculous. I know some of the vibration is down to the unconventional exhaust but it’s definitely become a little more pronounced since changing from the hoops to the block mounts at the rear.

Interestingly, despite an exhaust which is just a long pipe with a back box on the end, and no cat, EGR or DPF, the car passed it’s last MOT with zero issues, no emissions problems at all!

[Laird Scooby]

Originally Posted by AllHailKingVolvo

There is no middle box on my system! It’s a stainless custom system that was made for the PO, it’s essentially straight-piped bar one back box, hence the lack of supports midships-the rear box is the only thing that can have a hanger fitted to it!

It’s a noisy system, but not gratuitous. The back box has some baffles removed as part of the build and it’s throaty but not ridiculous. I know some of the vibration is down to the unconventional exhaust but it’s definitely become a little more pronounced since changing from the hoops to the block mounts at the rear.

Interestingly, despite an exhaust which is just a long pipe with a back box on the end, and no cat, EGR or DPF, the car passed it’s last MOT with zero issues, no emissions problems at all!

That might explain a bit about the vibration Phil, rough rule of thumb is diesels don't have or like back pressure, petrols do. I think it's too early for a diseasel cat, definitely too early for a DPF (luckily for you!) and the EGR is one less thing to go wrong - fine when they work but on diseasels are more prone to play up and confuse the mixture.

You could make a mount to go where the middle box would normally be, there are universal mounts available that are basically a round clamp with a rubber strap and the clamp goes on the pipe, the rubber strap is then bolted to a convenient point on the body.
However, i'd suggest bending a piece of 10mm round bar to suit/imitate the original bracket, use two normal mounts and connect the rubber strap to the centre of the 10mm bar.
Alternatively get a longer piece of 10mm bar and bend it so it has two L shapes at the top and either weld it on to a normal exhaust U clamp that can be bolted onto the pipe or bend it to support the pipe.

Just a couple of ideas.......

[AllHailKingVolvo]

Thanks Dave, that’s an excellent plan-I’ll try it!

In the meantime, I found that the alternator tensioner clamp bolt was loose, so the alternator belt had lost quite a bit of tension and the alternator was rattling about whilst the engine was running-all tightened up and sorted now, and no more weird noises when pointing up/down hills!

Said bolt/nut has worked loose a couple of times now. I suspect some sort of resonant frequency is causing it to chatter itself loose. I’ll replace it with a nyloc nut at some point methinks to see if that solves the issue.