Bjorn - '85 Vario making noises

[S10NPH]

I thought it was time to resurrect my Bjorn noises thread and post a little update.

Bjorn has been behaving well, and many of you will have seen him at the VOC National event in June, where I am pleased to say he came runner up in the 300 category

Anyway, as I was driving BHX to the show, my friend Oliver was kindly driving Bjorn. By the time he got back home to Cambridge on the Sunday, he said that he was nearly deafened and his ears were ringing, because of the sheer noise coming from the car.

So, a few weeks later I decided to do some investigating. I was sure that the vario system was all working properly, so I had a little brain-wave - if I revved the car whilst in neutral, and so the transmission was totally stationary, was there still excessive noise? Answer, yes there was. There was a clear extra rumble coming from the rear of the car. When I repeated the same test in my 345, the only thing making more noise the more I revved in neutral was the engine itself. So, exhaust is possibly the issue, methinks.

At this point, I decided to film a little video: http://www.youtube.com/watch?v=5NQMkhqQ5Lk

Anyway, I trundled along to my local friendly garage (is there really such a thing?!), and asked them to diagnose my dodgy exhaust - missing baffles in an aged silencer, I thought. Apparently not - the mechanic said it was a very new exhaust systems, and it had no problems, all working as it should.

Hmm, I was still not satisfied, so had a bit of a poke around myself. Now, what do I spy here:


A closer look:


The towbar is clearly touching the rear silencer. I think I found my culprit!

So last Sunday, I decided to remove the towbar. An hour's job, I thought, only 6 bolts to undo. Oh no, those bumper bolts are evil bastards. The whole damn day it took, my hands were raw, my face was covered in towbar rust and dust, and my arms, back and hands were aching in places I never knew I even had muscles. And even when all the bolts had come off, the bloody towbar refused to comply with gravity and kept hanging on for dear life by dangling from the exhaust pipe. Anyway, I finally got it free, and I think that normality has now returned. Oh, I bought brand new bolts from B&Q to replace the bumper bolts, there was no way I was spending another 6 hours painfully winding those rusty nuts back onto the original bolts. See, even I bow to practicality in the face of originality sometimes!

Here is a new video, post-towbar: http://www.youtube.com/watch?v=P8QWQEaZnTQ Sorry about the quality of this one, twas a bit dark and my mount was getting shaky.

I think there is a marked difference in the noise level, I am very pleased Need to take it on a long journey to see if it is now more bearable.

[macplaxton]

and my arms, back and hands were aching in places I never knew I even had muscles.

Try it again in another ten years...

I think I found my culprit!

I think you have found a chunk of your culprit, however a quick listen to the video still makes me thing I hear the "whistlely" note to the transmission.

If I get a chance I'll do a video of mine, but the downpipe and rear silencer really need doing first.

[S10NPH]

I like the whistling! Well I might have my hands on another comparator in a few weeks.

[macplaxton]

I like the whistling!

Well that's okay if it's a Roger Whittaker record, however a Variomatic is not.

[S10NPH]

I was told by the Essex Dafs boys who took it for a thrashing down the country roads that there was possibly a noisy bearing in the transmission, but that it wasn't worth the hassle of investigating further. I'm not sure that's what might give rise to the whistling though?

[S10NPH]

Time for a little update on this car.

When I was over in the Netherlands, I got my hands on some brand new Volvo variomatic drive belts.

So, on Saturday, I headed to Essex DAFs to have a proper look at the vario system and to swap the belts from the noisy Roflex ones. A task which we all thought would take a couple of hours, and we'd all be home by lunchtime. Or was it...

Work on the car started at a leisurely pace, with Matt and Eric (regular Essex DAFers) doing most of the work. It was only when we worked out that the secondary unit was already as far forwards as possible did we realise that we weren't going to have quite such a straightforward job as we thought. The belts on the car were very tight, even with the secondary as far forwards as possible, so there was no way to get any more slack before trying to get the belts out of the secondary pulleys.


The next step was to try spreading the pulleys with a trolley jack and some blocks of wood, but as the belts were so tight, it ended up lifting up the car more than spreading the pulleys. After a lot of cursing, that idea was abandoned in favour of the G-clamp method. The only issue then was finding something to wedge in the pulleys to keep them open - everything that was tried was spat out again by the pulleys. Eventually, some brute force on the primaries whilst the G-clamp was in place gave enough slack to unhook the belts off the secondarys, the first of which slammed shut with an almighty bang as soon as the belt came off. The old belts were in good condition, apart from a split along the length of both belts about 2 inches long about 2mm in from the edge. A bodge with a screwdriver when fitting them was suspected.

The new belts were Volvo branded ones (made in Mexico on the belts, made in USA on the bag, not sure what's going on there!), and they were much narrower than the Roflex ones. They were also slightly rounded, which Matt and Eric thought was unusual. In any case, the more narrow profile meant that they slipped on nicely, and then allowed plenty of adjustment of the secondary pulleys to settle them in properly. Closing up was fairly straightforward (apart from the dried underseal flaking right into Matt's eyes on many occasions, sorry Matt), and a quick blast up the road confirmed that the new belts not only worked perfectly, but were also quiet and smooth.

The journey back to Cambridge was absolutely fine, the only issue being a slight boom from the engine or exhaust when cruising over 60mph - this will require some more investigation, but is not related to the belts. I'm not sure if there is an exhaust issue, or something more serious with the engine. But anyway, the new belts now only give a whisper of a variomatic noise rather than a loud whistle, and they no longer grind when cold frightening my neighbours. The pick-up from stationary is also smooth.

Volvo in a DAF service area:


The working position of the car:


And after the job finished, a line up with Eric's very clean 1991 vario:


After getting it home, I realised that the carb bolts had loosened, so they were all tightened up. The flap inside the air filter neck is also vibrating - how loose is this meant to be? I don't have a comparator with the 81-on air filter.

[S10NPH]

Just a quick update, I took Mac for a short ride in Bjorn this afternoon, and the conclusion is definitely that there is a resonance to be heard consequent on throttle position, but only above about 60mph. It's either the exhaust is rubbing against something, or there is a broken baffle in one of the silencers. I will do a little investigation someday, but for the moment I am content that finally, I have a correctly functioning CVT system and a car that is a pleasure to drive.

[macplaxton]

Exhaust baffle. Abby used to do it around 65mph.

[S10NPH]

Yeah, sounds about right. It's probably always been there, just I've never isolated it before above all the other noises!

[macplaxton]

Just drive it faster. Peace and tranquility resumes at 70mph.