How to check Sigma 125 timing???

[KRL]

Looking for some help here.

 

After a cam belt change I am not sure the timing has been set up correctly on my 125 Sigma. I've already taken the car back to the garage once and they re-adjusted it according Caterham spec. Although better than previously I'm still not convinced the timing is correct.

 

Is there a way (hopefully easy!) I can check the timing on my sigma? On a previous car (Audi S3) I used to be able to be able to check timing advance on a laptop with VCDS. Is similar possible with the sigma? Or is it not possible to check with a laptop?

 

Any help with ideas or suggestions would be much appreciated as I am a little stuck.

 

Edited by - KRL on 30 May 2014 19:00:17

[ChrisC]

I have the lead, you can get it from SBD, but I am not sure there is any cam timing information, only ignition and injection, but I could be wrong. Was the garage a caterham specialist? Is there a reason you think the timing is wrong, is it down on power?

 

 

[KRL]

Thanks for the reply. Yes it was a caterham specialist.

 

The car feels to have lost a little bit of oomph at the top end. After a recent track day at Snetterton I was not reaching the same top speeds on the straights and can see from the shift lights in video footage (past vs present) that it is taking longer to rev out in 4th gear.

 

I guess I want to be sure myself before taking it back for a 3rd time (or going somewhere else). Thus wanting to check / prove it somehow.

[ChrisC]

Know anyone local you could compare with?

[KRL]

No sigma owners locally that I know of unfortunately.

[DJ.]

I changed the timing belt on my Sigma recently and found the inlet cam was retarded.

I had assumed I could use the Ford tool to set the cam timing, so phoned Caterham who were reluctant to give me a precise way to set the cam timing. They told me if I just used the Ford tool that the engine would run fine but I'd be down on power or I could take the car to them and pay to have it reset.

 

I ended up setting it by eye using the tool as reference, and when I went on track I was hitting the same speed as previously. I have some photos of the cam position which I could send you so you can compare to your current position.

 

Duncan

 

Edited by - DJ. on 29 May 2014 22:12:29

[6speedmanual]

DJ

Is what you're saying that Caterham have a "tweak" to the cam timing of the Ford cams or are they Caterham cams for which they do not want to disclose the timing data?

 

Try telling them that under European Block Exemption regulations OEMs are required to make available service and repair data to individuals and independent non-franchised repairers.

 

Peter

[DJ.]

They are standard Ford cams, all Caterham do is retard the inlet cam and yes they were less than helpful when I asked if I could get a special tool or if they could give me the correct way to set it.

[Mankee]

Where abouts in Suffolk are you? Wondering if some time spent on the rollers to adjust the cam timing will be of benefit. However, I don't know how or if this is possible with a Sigma engine, so this may not be applicable!

[ChrisC]

The sigma uses friction fit for the cam pulleys, not a key way so well possible to spend some time on the rollers getting it right.

 

[KRL]

Quoting DJ.: 

I changed the timing belt on my Sigma recently and found the inlet cam was retarded.

I had assumed I could use the Ford tool to set the cam timing, so phoned Caterham who were reluctant to give me a precise way to set the cam timing. They told me if I just used the Ford tool that the engine would run fine but I'd be down on power or I could take the car to them and pay to have it reset.

 

I ended up setting it by eye using the tool as reference, and when I went on track I was hitting the same speed as previously. I have some photos of the cam position which I could send you so you can compare to your current position.

 

Duncan

 

Edited by - DJ. on 29 May 2014 22:12:29

 

If you could send me the pictures that would be great thanks.

[KRL]

Quoting Mankee: 

Where abouts in Suffolk are you?

 

Bury St Edmunds.

[KRL]

Quoting ChrisC: 

The sigma uses friction fit for the cam pulleys, not a key way so well possible to spend some time on the rollers getting it right.

 

Sorry just to clarify you are saying a session on the rollers would be of benefit?

[ChrisC]

Just saying its possible to alter the cam timing without the need for special key ways or adjustable pulleys, so you could adjust them on the rollers and see the effect.

[Guest]

I have a 2010 Sigma and am just south of Ipswich. Welcome to take a look if it help at all.

Paul

[SKC]

Hi All,

 

The Sigma, as a road engine is designed to be assembled as quickly as possible on a production line using setting tools and gauges to accurately set the cam timing.

 

The issue you have here is that the 140 Sigma doesn't use standard cams and hence I'm not sure how Caterham set the cam timing (whether they use a gauge plate in the rear of the cam at TDC or not).

 

None of this would be an issue if you didn't have to remove the crank damper pulley from the front of the engine. This is held in place with a bolt that is extremely tight as it not only retains the damper pulley but also clamps the crank drive sprocket for the timing belt. In the process of loosening the damper pulley alone, cam timing can be altered. Altered cam timing can not only mean a lose of power but can lead to very serious engine damage if pistons and valves should meet at high speed!!

 

This is partly why we remove and leave off the belt covers on our engines so that cam belts can be changed easily and quickly. A belt change on one of our engines should take any longer than 15 minutes. I know there are those out there that will say "well what about stones in the cam belt". My answer to that is stay on the black stuff and you shouldn't have a problem.

 

Back to the original topic, basically if you have a 140 Sigma, get the cam belt changed by Caterham or if you want us to do it, we'll have to measure all the cam settings before we remove the belt so we can accurately reset it with the new belt.

 

Regards

 

SKC

[KRL]

Just to confirm my car is a 125 Sigma, I should have made that clear at the begining so I've changed the title.

[KRL]

Quoting SKC: 

Hi All,

 

The Sigma, as a road engine is designed to be assembled as quickly as possible on a production line using setting tools and gauges to accurately set the cam timing.

 

The issue you have here is that the 140 Sigma doesn't use standard cams and hence I'm not sure how Caterham set the cam timing (whether they use a gauge plate in the rear of the cam at TDC or not).

 

None of this would be an issue if you didn't have to remove the crank damper pulley from the front of the engine. This is held in place with a bolt that is extremely tight as it not only retains the damper pulley but also clamps the crank drive sprocket for the timing belt. In the process of loosening the damper pulley alone, cam timing can be altered. Altered cam timing can not only mean a lose of power but can lead to very serious engine damage if pistons and valves should meet at high speed!!

 

This is partly why we remove and leave off the belt covers on our engines so that cam belts can be changed easily and quickly. A belt change on one of our engines should take any longer than 15 minutes. I know there are those out there that will say "well what about stones in the cam belt". My answer to that is stay on the black stuff and you shouldn't have a problem.

 

Back to the original topic, basically if you have a 140 Sigma, get the cam belt changed by Caterham or if you want us to do it, we'll have to measure all the cam settings before we remove the belt so we can accurately reset it with the new belt.

 

Regards

 

SKC

 

Many thanks for the reply SKC. As I said above my car is a 125 Sigma so therefore I believe should be using the standard ford cams.

 

 

[KRL]

Quoting pmr: 

I have a 2010 Sigma and am just south of Ipswich. Welcome to take a look if it help at all.

Paul

 

Thanks for the offer Paul. I may be in touch at some point. Are you a 125 or a 140?

[Guest]

125 Sigma, standard apart from the valve spring upgrade I believe. No problem, just let me know.

 

Paul

[KRL]

Hi All,

 

I wanted to update this thread so here goes...

 

Well I'm very pleased to say my car is back to normal now. With Duncan's help (D.J) I was able to confirm beyond doubt that my cam timing had not been setup correctly compared to Duncan's. So thank you very much to Duncan and everyone who contributed on the thread.

 

As I do not know Caterhams specific settings for the cam timing on the 125 I took the decision to take the car to Caterham Dartford and have the timing adjusted. Caterham did a great job with no fuss at all and now some 2.5 months after the original cam belt change I have a properly performing car.

 

I think there is an important lesson to be learned here. Please make sure when you have a cam belt change on the sigma that the cam timing settings are fully known and understood by the person undertaking the work. The cams should not be reset to Ford specification using the Ford cam timing tool in the camshaft slots. Caterham measure and set the cam timing using gauges to check the valve clearences and these settings need to known before attempting the cam belt change.

 

If you have any doubt about this then take the car to Caterham themselves for the cam belt change. For me it was a simple case of logistics with Caterham being quite a bit further from me than the Caterham Specialist.

 

In my case it is clear the garage did not take any measurements before changing the cam belt and thus were then unable to set the cam timing up correctly. I'd like to emphasise that I took my car to local Caterham specialist with a very good reputation but unfortunately it appears they were not familiar with the Caterham Sigma engine and timing requirements for a cam belt change. I will be following up with the garage myself to hopefully prevent the same mistake being made on any other Sigma engines taken to them in the future.