Running in ailments

[Mucus72]

Just a quick report back on alternator. I removed the belt at the tensioner - interestingly that bolt itself wasn't very tight, its opposite thread to normal, when I exerted anticlockwise force to reduce tension on the belt and slip it off the tensioner pulley, there was  an easy ability for me to tighten the bolt further, so I did. 

The alternator itself rotates smoothly and with no spring back, so it seems ok.

7Wonders - the exhaust is mounted on a singerrear rubber bobbin, standard Caterham item. My old K series had a forward mount point too, but this has only one. The bobbin is working correctly and damping as it should. To truly test this i could whip off the silencer and fire it up, but I will frighten the neighbours...

Seeing as the engine when running is really vibrating like mad and the exhaust is not, I feel that at this stage I don't need to do that. 

My problem is the way in which the engine itself is running, at whatever rev range or load, irrespective of clutch, so we can take the gearbox out of the equation.

Its going back to BookaTrack tomorrow and they have it for a week or so to do further tests.

I am pretty sure that there are some Duratec experts on here, that do this kind of thing as a business. Any ideas I can pass on to BaT beyond what has been discussed on this thread to date would be very much appreciated.

 

[Mucus72]

Out of interest I thought the maps in standard cars (which mine is) were locked. When I spoke to Troy at NMS he suggested that an early upgrade would be to replace to locked MBE ECU with an unlocked one.

I know that others have been supplied with ECUs with the wrong map flashed to them. Now my car does drive pretty well apart from the mega vibrations. I wonder whether a tweak to the map (or even checking of) would be possible by the Caterham franchise dealer?

[mw]

Hi 

Can i throw in my experience, such as its worth.

My day car had a new cat fitted.

Driving  the car home felt as though someone had change the engine to a sports model.

The car appeared to be much more responsive, sounded sporty when faster? with a lot of feed back and vibration through steering wheel, gear stick.

After a few days i became tired of the noise and vibrations, took the car back to find that the cat was touching the heat shield, my old car was back!     

[John Vine]

I removed the belt at the tensioner - interestingly that bolt itself wasn't very tight

While the belt was off, did you also check that the tensioner pulley itself operated smoothly?  It spins at a similar speed to the alt (maybe even faster).  Also, I'm surprised the bolt wasn't tight as IME they're usually very tight.

Here's hoping Bat/CC can resolve things quickly.

JV

[Jonathan Kay]

There are smart 'phone apps which claim to analyse *vibrations. That should make it possible to compare engines etc, even remotely. And the frequency spectrum might give a clue, as in Andrew's thoughts.

http://usefulmobileapps.com/img/vibration-spectrum-analysis19.png

Jonathan

* Careful with that search, Eugene.

[Mucus72]

Morning all,

I dropped my car off at BaT yesterday evening and when there I tested another 420R - not driven, there was no time, but with both cars side by side, both cars from a cold start, I used an expensive (£3.99) iPhone App and rested the phone on the cam cover, back of phone flat to cover, phone oriented north-south along the longitudinal direction of the car and engine. Same location on both cars.

X is the deflection left right

Y is the deflection in the same plane top bottom (of phone) i.e. north-south longitudinal to car.

Z is the deflection up down 

Both tests were within 30 secs of starting the engines (I trailered my car and pushed it next to the other). Idle will have been set differently.  All other test conditions were identical. 

Image 1, My car time series:

Image 2, the other car, time series:

Image 3, my car frequency graph:

Image 4, the other car frequency graph:

[Mucus72]

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]

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

Jonathan

[revilla]

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?

[SM25T]

Hope you don't need a new phone after that experiment on the cam cover.

[Mucus72]

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]

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

Jonathan

[Mucus72]

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]

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!

[Jonathan Kay]

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]

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.

[griffchris]

Ditto, I had exactly this problem with leaking brake fluid and bubbling paint work - I think leakage was from the clutch and brake master cylinders - came to light after doing lots of donuts at Throckmorton!

 

Replaced both caps with plastic ford master cylinder caps from eBay, again tie wrapped in blue paper roll - so far so good......

Chris