Running in ailments

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Mucus72
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I'd now like to follow up with Andrew Revill's first thoughts on seeing these charts, and note that I am copying verbatim and he was only comparing on an iPhone screen.

I would appreciate some help here and verification of Andrew's findings if at all possible?

Thanks in advance

Marcus

Andrews comments:

"If I'm reading it right the peak frequency on yours is around 980hz and on the other 1240hz. That just has to be 1hz/rpm with your car idling at 980rpm and the other 1240rpm - I'm guessing the other one was cold?

So one vibration per crank rotation. If it was camshaft related it would be half that. If it was vibration from the firing strokes it would be twice that (four cylinders firing every second rotation). If it was alternator or pumps it would be geared up higher due to the differences in the pulley sizes. So it sounds like it must be crank related.

If I had to hazard a guess I would say something rotating or reciprocating with the crank is out of balance. So crankshaft, flywheel or clutch out of balance or poorly matched piston or con rod weights. But that is all from first principles and not from previous experience of such problems."

Jonathan Kay
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Nice work, and I hope that this approach will be useful to others.

Jonathan

revilla
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Marcus, I wrote that email half asleep after an exhausting day with the children with on eye on the television. Some of my wording didn't make much sense, although I knew what I meant and I think the logic was right.

The sentence: 

If I'm reading it right the peak frequency on yours is around 980hz and on the other 1240hz. That just has to be 1hz/rpm with your car idling at 980rpm and the other 1240rpm - I'm guessing the other one was cold?

Should read:

If I'm reading it right the peak frequency on yours is around 16.33hz or 980 cycles per minute and on the other 20.66hz or 1240 cycles per minute. That just has to be 1 cycle per crank revolution with your car idling at 980rpm and the other 1240rpm - I'm guessing the other one was cold?

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm

SM25T
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Hope you don't need a new phone after that experiment on the cam cover.
Mucus72
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Just a quick update. The guys at Book a Track have had my car in for testing this week and report back that they think it's all ok and that the level of vibration is normal. I'm going to pop in and sample another car with the same engine, and I know of at least 3 local cars with the same engine built between end of 2014 and now. So it looks like it's up to me to prove there is a problem that warrants further investigation. As it stands I'm not accepting the engine. Would be grateful if there are any folk on here who have experience of Duratecs could assist. Even if it means taking it to a specialist for review. 

Jonathan Kay
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Don't forget to record the evidence with that app.

Jonathan

Mucus72
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It's update time again folks!

BookaTrack were hosts for the end of season Caterham racing party last weekend. My car was with them, and as luck would have it Simon Lambert, big cheese technical director and general good egg was around to have a drive in my car.

The plan was to start by swapping out the engine mounts. This happened and I picked up the car late Saturday afternoon for further testing myself.

Had fantastic drive on Sunday afternoon around south east Leicestershire (Loughborough down to Market Harborough), up around Rutland Water and back. So a nearly 2 hour drive.

The vibrations I'm feeling are CONSIDERABLY less. Im still getting a very slight "fizzing" through the accelerator, seat base (GRP racing snake jobbies) and steering wheel. The secondary vibration of everything hanging off the back of the dashboard has dissipated too, 

And so my summary of the above is that I now think I'm in "normal" territory for a Caterham in terms of agricultural delights.

It's still not as smooth as my old K series.

I am popping up to BaT to drive the other new 420R SV they have in stock currently, and will do so between now and the weekend. I want to double check to be sure before I close the issue with them and Caterham.

Both BaT and their relationship with Caterham here to help me is pretty impressive. BaT themselves continue to impress me.

One final note though, and sort of BTTT about my original post on this thread. I experienced a leaking master brake cylinder, and was offered a race cylinder cap (no low level sensor) or another cylinder so that I could double up on the rubber o-ring thickness. Basically Caterham acknowledged, through this process, that the current o-ring is not sufficient to stop leaks. I went with the doubling up to create a thicker o ring. Seemed far safer than running around not knowing if I have brake fluid or not.

It so transpires that a lot of the POBC have experienced this issue too. In my case leaking fluid after just one 50 mile drive stripped a section of paint from the top edge of the side skin near the leak onto the scuttle. Caterham are not acknowledging the repainting of this roughly 20 pence sized bare aluminum as warranty repair. I can't personally see it any other way, can you?

 

 

revilla
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So it was the engine mounts after all? Glad it's sorted. Still seems a little off to me that the engine itself seemed to be vibrating so much when we looked at it. I can imagine the engine mounts transmitting more vibration to the chassis but if they were too solid, intuitively I would have expected more vibration in the chassis but less in the engine. Maybe I was being a bit unfair comparing a duratec with a K and maybe the difference we felt was more just the difference between engine types. Anyway, glad you are happier with it!

SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm

Jonathan Kay
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It so transpires that a lot of the POBC have experienced this issue too. In my case leaking fluid after just one 50 mile drive stripped a section of paint from the top edge of the side skin near the leak onto the scuttle. Caterham are not acknowledging the repainting of this roughly 20 pence sized bare aluminum as warranty repair. I can't personally see it any other way, can you?

Not really.

Fancy claiming? The acknowledged fault with the sealing and the documented similar problems on other cars would carry enormous weight.

Jonathan

ScottR400D
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I had the same paint issue after my clutch cylinder leaked. I stopped the leak by replacing the cheap original with a girling cap. 

My brake cylinder hadn't leaked as far as I know but I keep both cylinders 'wrapped' with blue wipe roll just in case. I repainted the top of the side panel using an aerosol and, though you'd know if you looked closely, it's hardly noticeable.