Zeus timing gear conversions?

so MichaelT was, like...

Google it, especially on this group - there was quite a discussion a while ago. Some very much for, some against. A summary, as I recall it - noisier, stays in tune better, slight improvement in economy, early problems with plastic gears later solved, very expensive, not a good idea for expedition vehicles as parts not easily available world-wide if it does go wrong. The guy who was importing them to (I think) Oz had a lot to say, all in favour as you might imagine.

Plenty to read if you look for it.

Well after finding out how much it cost to buy it and (if I wanted them to fit it) + VAT just over £1K, I thought the longevity of a belt and the damage that is caused by a snapped belt, you could repair with new parts 4 times for £1K. The engines probably knackard by then, so I would rather stick with what I have got and its alot quieter than poxy gears!

Alistair

I have no personal experience of the Zeus timing gear conversion but a good friend of mine had it done on his 300Tdi Discovery and doesn't have a bad word to say about it ... or the company. He took the vehicle to Exeter to have the conversion done by Zeus (who provided his with a loan car for the day). When he went back to collect the car the work had been completed and the vehicle valeted. They pointed out a couple of things they had noticed whilst doing the job that would need attention in the future - hoses starting to crack, etc.

My mate called me on his mobile on the way back home and was very enthusiastic. According to his initial assessment the Discovery was much livelier, especially in the mid-range, and not noticeably noisier. Lets face it a 300Tdi ain't the quietest engine ever made :-)

It's been about 18 months since he had the conversion done and the Disco has covered loads of miles (to and from Germany every week) and he still enthuses about it. I've stood with the bonnet up and listening hard could hear the gears whirring away .. but it's hardly "noisy". He hasn't been able to tell if the gear modification improved fuel consumption because just a week later he had an Allard inter-cooler fitted.

HTH

On or around Thu, 08 Sep 2005 05:59:24 GMT, "MichaelT" enlightened us thusly:

They're reputed to be noisier than a belt.

Hi Michael, I'm the bloke in Australia who "went to bat" for the Zeus gears when they were attacked on the forum.

I know well the site that Pantellis refers to,and all I can say is that all is not what it appears. I've defended the gears in the forums and also in the legal system and in both cases am happy with the results.

My own Disco had gears fitted at 103000km and they're going fine at

216,000 km. If you visit our website

you will see that dyno data on the improvement in performance (about

27%, and fuel improvement is around 12%).

In real terms all this means I get about 120 kms extra per tank, and can use my engine from 1100rpm upwards. On the timing belt you need to wait for the turbo which comes in at 1850 rpm.

About 3 yrs ago I worked out that within 75000 kms a person with gears saves money compared to someone on timing belt when its changed every

50000kms. Given the recent 35 % increase in diesel prices the period is shorter.

I have both a disco and defender with the gears fitted, and wouldn't want to even think of driving a 300 with the rubber timing belt.

Yes there is a bit more noise at idle, but this is from the injector pump lifters. Yes there is an improvement in economy and better performance as the engine can now be used from 1100 rpm, which makes towing, around town driving in traffic , off road driving all much better. If you have an automatic then the improvement is very noticeable on cold mornings when the engine is cold.

As I have stated frequently in the public domain, I'm a real user and believer in the Zeus timing gears. I've thoroughly researched all the "stories" and "expert opinions" and nothing has caused me to change my opinion on the gears, nor seen any reason to stop selling them or remove them from my own vehicles or those of many of my friends.

I would suggest you ring Graham at Zeus and speak to him directly about the gears. Ask him the longest mileage on a set of gears that he has seen ( about 250,000 miles).

Cheers

Phillip Simpson

Phillip Hi,

I would be extremely interested to get more recent news on the development of the dispute with the person who had this negative experience with the Zeus timing kit(s).

There are a so many apparent advantages on this timing gear setup that it is a pity for such a case to be creating problems to it for what appears to be an unfortunate but extremely rare case.

Your valued input is expected with interest and anticipation.

Take care Pantelis

Beats me what the hell was wrong with Landrover that they couldn't stick to a timing chain in the first place.

Alex

so Phillip Simpson was, like...

Phillip - I read all your comments on this a while back (hope I wasn't too rude when I summarised it in an earlier post). What puzzles me is why a vehicle with timing gears is said to perform so much better - in performance and economy. There is a certain relationship between cam, crank and injector pump which a newly-fitted belt will maintain, and presumably the gearset will keep this relationship. How can a gearset improve on a new belt? I can see a gearset maintaining the settings better than a belt over time as the belt will wear and stretch (although when I took the old cambelt off my 300Tdi it was a bit of a wrestling match, so it can't have stretched much!) - but not by 27%. What do the gears do that a belt can't?

Hi Richard, no problem with your summary.

I see you have an auto, so will be familiar with the cold morning "lack of power" I was referring to.

The dyno study I refer to was on my disco with a new timing belt fitted approx 3700km prior to the study. Like you I was surprised at the amount of improvement, but found it very reproduceable.

The real test is not how hard it is to pull the old belt off, but to measure the position of the injector pump and cam shaft variation with the engine locked at TDC- see how much anti clockwise movement you can get on the pump and camshaft. Remember that when you're doing this, the engine isn't under load, so you are looking at minimums, when it comes to the amount of retardation. I have never seen a belt that wasn't stretched and that didn't cause both the injector pump and cam shaft to be retarded. This is what causes the deterioration in performance with the belt. The gears simply keep the timing the same, irrespective of the engine speed etc. Given the loading at the lower revs, until the turbo comes in, is why the difference is so marked.

It doesn't take much retarding of the injector pump or cam shaft to have an impact on the performance, so the comparison with geared timing is pretty elementary. I had heard a lot of anectedotal comments on the gears "extra performance" which was why I had the dyno study done at the local technical college. We actually did the study on 2 vehicles (my disco and a low km defender) and the results were the same.

The 27% is not the amount of belt stretch, but rather the improvement in power. As you can see from the graph it is a peak, and happens at the lower rpm range. I don't know the maths to calculate the timing belt variance needed to give X degrees variation on the pump, but remember that it is both the camshaft and the pump that are retarded.

All the gears are doing is maintaining the timing with the constant geometry of gears as compared to the variable nature of belts. Even timing chains vary with time, and with the timing belt the effect simply happens sooner.

Hopefully this answers your questions, but if not just keep sending them.

Cheers

Phillip >so Phillip Simpson was, like...

Hi Pantelis, there has been no further developements in the last couple of years. The issue was taken before a tribunal (small claims court)by the people involved and the original case, and subsequent appeal that they made were unsuccesful ie no case was proven against the Zeus gears, Zeus or my own company. Interestingly the people who produce the website you refer to, were not accepted by the tribunial to act as expert witnesses and present data or be cross examined on their opinions.

The sad thing is that while we won the case, they perhaps have a win by publishing material that causes doubt. This does 2 things, and you are a good example of one of them ie you didn't purchase gears because of the doubt that was created. Secondly it devalues the resale price on those vehicles where people have gears fitted. Fortunately most people fit the gears to enable them to keep the vehicle for a long period of time, so this is less of an issue.

All I can say is that with the increase in diesel prices, and the way my disco performs, I'm glad I've got gears fitted. Perhaps I've failed in countering the bad stories, but such is the way of the world. As one song writer wrote, "good news never sells papers".

Cheers

Phillip

so Phillip Simpson was, like...

Not since I gave it to Jeremy Fearn for a day! Seriously, it's not too bad, and I'd never considered cold running to be a problem. However...

I was only joking here - if that's a stretched belt, how tight is a new one going to be? (I found out about an hour later. Bástard tight is the technical term.)

Surely when the turbo comes in that will increase the loading on the belt? The crank pulley is pulling the belt round against the resistance of the cam and pump pulleys, so the harder it pulls the more the belt will try to stretch.

I can see the reasoning here, although logically if the difference is due to the absence of belt stretch you would see only a marginal difference over a new belt and a bigger improvement compared with a well-worn belt. Your dyno tests were on an almost new belt (just over 2k miles).

That's how I read it - I was being a little humorous. Although considering how much modification you need to do to a standard engine to push the output up by 27%, I'm surprised that the gearset can achieve this on its own. Either the gearset is working some kind of magic, or the original setup is thoroughly crap.

I read this group on a non-binary server, so no graph.

The principle makes sense, but I'm still a little amazed that the Zeus gears can give such an improvement merely by keeping the crank/pump/cam timing as it should be. Why didn't LR think of this? Cost?

Why not just fit a duplex chain ?

Steve

Hi Richard, as you have seen, the belt needs to be very tight. The point of testing a new belt was to show that even when they've done only a small amount of work, they impact the timing, performance etc. If I ever had heaps of time and money, it would be interesting to run the tests on new belt, 2000 miles up to 8000 miles, as the variance starts quite soon.

The other interesting point of the impact of the Zeus gears on timing etc, is the big difference in the exhaust emmissions. With the gears, and simply due to correct timing, there is an enormous reduction in exhaust emmissions. I didn't collect any data on this as its not part of regular testing preocess in Australia like you have on the MOT system.

Who knows why LR do anything, but I suspect that the 200 timing belt was OK, so since it is cheaper and quieter they continued with the belts. Funny how this was changed with the TD5- one explanation I've heard is that the belt didn't have enough control to meet the EEC exhaust emmission specs, which were becoming increasingly tighter.

Cheers

Phillip

PS The graph is on our website, not on the newsgroup

. As

Phillip Hi,

I totally agree with you on that. I guess your lawyers should ask for the inclusion of the tribunal's decision in the offending site.

The main reason I decided not to fit the Zeus kit was only because I do not expect to cover the distance required to set-off the expense of the kit and its fitting. I do not cover more than 15.000 to 20.000 km annualy so it did not make any sense to invest for the kit. But I have to accept that the site has had its negative contribution to my decision not to fit the kit eventhough it is a very tempting suggestion on performance and fuel economy grounds.

As for fuel economy I have opted for another solution which gave excellent results but that topic has already been discussed to its exhaustion on this newsgroup. But I still get around 15% less on my fuel bills.

Take care Pantelis

On or around Thu, 8 Sep 2005 23:10:29 +0100, "Richard Brookman" enlightened us thusly:

not sure if that's valid - the resistance of cams and pump is not going to increase linearly, I wouldn't think.

I suspect the problem is that the engines are set up static and run dynamic

- the belt behaving differently as a result - a bit like the effects you get from static ignition timing versus dynamic ignition timing.

I'm reluctant to play with cam timing on the TDi, though - there's no great room for error. When we had to have the head off ours, there was evidence that in the past the exhaust valves have hit the pistons.

COULD you fit a timing chain to a 200Tdi....

Steve

On or around Fri, 09 Sep 2005 09:54:34 +0100, Steve Taylor enlightened us thusly:

anything's possible. Not all things are practical, however. "All" you need is a suitable set of sprockets and a chain the right length. And maybe mods to the tensioner, and a means of lubing it, and a means of draining the lube back to the sump (easy enough, timing case drain piped into the sump) and of course the casing would need to be made oil-tight if it wasn't already.

replying to Pantelis Giamarellos, Carl Pretorius wrote: Hi, I have a system like this that came stripped to me and now I want to assemble it back together but the vehicle is lazy. Does anyone have a installation manual so I can verify my marks or so?