Ignition Timing S3C

[jimed]

I've been running the S3C at 12 BTDC as per Steve Heath's book - 1st edn but have noticed on the TVR S Series website the Haynes technical bit says 12 BTDC for the 2.9 cars and 15BTDC for the 2.9 cat version cars - both at 900 RPM. Hmm!!
Does anyone know which is correct and what difference the std tickover of 1000 rpm means to the advance in terms of the above??
Jim

Later: I've just looked at the Haynes Granada manual and that says 12 BTDC without Cats but 15BTDC with Catalyst fitted which seems to support the above (still Haynes though so is it just picking up the Granada data?) but as the management setup is different (I think) for S's is it the same???

Edited by jimed on Monday 25th August 20:14

[tozerman]

jimed said:

I've been running the S3C at 12 BTDC as per Steve Heath's book - 1st edn but have noticed on the TVR S Series website the Haynes technical bit says 12 BTDC for the 2.9 cars and 15BTDC for the 2.9 cat version cars - both at 900 RPM. Hmm!!
Does anyone know which is correct and what difference the std tickover of 1000 rpm means to the advance in terms of the above??
Jim

Later: I've just looked at the Haynes Granada manual and that says 12 BTDC without Cats but 15BTDC with Catalyst fitted which seems to support the above (still Haynes though) but as the management setup is different for S's is it the same???

Edited by jimed on Monday 25th August 19:49

That is a question I also would love to know the answer to aswell, has anybody tried both settings ? if so how did the car go ?

[jimed]

I've been looking at Steve Heath's book again (I know too much reading is dangerous stuff!) and it says that as the dissy is contactless there is little that you can do re timing - at least that is how I read it - so the timing is driven by other engine sensors and the ECU, which suggests that moving the dissy slightly (which in contact fitted dissys would alter the timing) would have no affect on the S (always assuming I didn't move it too far and alter the spark distribution to another cylinder). Does anyone know if that is correct - if so there is nothing I can do and I've got what I've got in terms of timing.
Maybe this is another of those black magic things .....
Jim

[ketvrin]

Hi Jim - when I set my timing, I replaced the dissy to the position it had been in before removal (marked before removal) and I used a strobe and was able to move the dissy to bring the pulley wheel timing marks in to the required 12 deg (Unleaded 95 RON Fuel used )and could hear the engine speed change as a result. The engine runs fine throughout the range.

I have seen various posts on putting the ECU into set-up mode and shortcuts like disconnecting the ISCV but have not been able to follow these with any success. My engine simply would not run with the ISCV disconnected This works for me but I'm not saying it is the correct way and all others are wrong

K

[jimed]

Hi Kevin - I think your car is an S3 rather than the C (?) and so it may be a bit different - but - when you moved the dissy without having disconnected anything else, etc. so as to put it into some other mode did it actually alter the timing or did it just sit at 12 btdc?? ie could you have set it at 13btdc or 14/15?? Any idea as it does seem strange that the granada version runs at 15btdc and the TVR one doesn't even though it apparently has a different ECU set up (does it or am I imagining that bit?) it wouldn't alter the basic timing - or would it ...
Confused S3C (aka Jim)

[ketvrin]

Hi Jim
yes as I moved the dissy you could see the timing changing on the marks with the strobe...

and yes you are correct mines an S3 (not the S3C)

K

Edited by ketvrin on Tuesday 26th August 16:50

[jimed]

Thanks Kevin - I may have a little play with the timing and see what happens - it may not be for a few days as friend with good strobe is away and I'm away this w/e for some sun but later in the month maybe.
I'd still be interested in knowing what it should be though 12/15btdc??
Jim

[Jed-S]

Last nihht I was looking through the manual for the ECU diags unit I have and it quoted 15 degrees BTDC for Sierra and Granada 2.9 with cat.

[tozerman]

I have just attempted to check the timing on my S3c with a view to setting it to 15 degrees BTDC if it wasn't there already. I ran the car up to normal working temperature by letting it idle for 10 - 15 minutes, got my old strobe light out from a corner of the garage, blew the dust off it connected it all up and guess what? the bl*"dy thing would not work !! to be fair it has not been used for about 10 years now but I was still P*ss*d off big time.
I will get to the bottom of it though, a new strobe is on order from Amazon so watch this space.
Cheers.....Tony..

[jimed]

I'm waiting to see where Tony gets to in timing terms with the new strobe but in the meantime was wondering what to try mine at as a sensible starter once I get the strobe sorted. Reason is I normally use Super unleaded but this can change from 97 to 99 octane dependant on brand and also I do sometimes need to use ordinary unleaded - so whilst the ECU will apparently allow me to use ordinary unleaded I would want to ensure that whatever I set it to would not (in all probability) be a problem with fuels other than is in it at the moment. ie if it could go to 15btdc with 99 octane what would the difference need to be to use the ordinary stuff? 1 degree less , 2 less?? Anyone any idea what the difference would be? Tat would enable me to see how far I could adjust it with the norma; fuel and then see how much I need to back off from there - it may sacrifice some performance but would ensure no pinking.
Jim

[tozerman]

Right then, parcel arrived from Amazon last week and I have just finished checking my car. I ran it up to normal temperature before doing anything, when I strobed it first I couldn't believe my eyes it was massively over advanced by approx 6 degrees, bearing in mind the previous owner took the car to John Noble Engines in Chesterfield to have it rolling road tuned and they set it to where it is now!!!!
So with the timing now set to 15 btdc exactly is it my imagination or does it idle a bit more smoothly ?
The proof of the pudding is in the driving, I doubt I will get time to road test it before Friday which is my day off so I will report back then and let you all know how it feels, although I have to say it drove perfectly well with the timing way out so it should be interesting.
I did take some pictures before and after but they didn't come out very well at all ! I think the flash just blocked out the xenon light from the strobe.
Cheers.....Tony..

[tozerman]

jimed said:

what would the difference need to be to use the ordinary stuff? 1 degree less , 2 less??
Jim

From memory it used to be 2 degrees retarded for 2 star/95 unleaded but I would guess that as the S3c runs at 15 btdc (on 95 ron! did they have super unleaded in the early nineties?)and that is already quite advanced it should be ok at 15 btdc with either 95 or 98ron fuel !
Cheers.....Tony..

[jimed]

Sounds very interesting Tony - I'm about to have a go at mine (next few days anyway) so will wait and see what you think of 15btdc. What octane are you running by the way?
Jim

[tozerman]

Jim YHM....

[tozerman]

Right then, went out yesterday afternoon filled it full of super unleaded and headed off into the peak district.
At first it wasn't very smooth when giving it some boot but it seemed to be a bit smoother when accelerating normally, at the same time as filling up I also put some injector cleaner in the tank which if it was doing its job properly could be just a bit of crap flushing through, after a while though it did improve markedly and also seemed to run a bit cooler ie just under 90 instead of dead on 90 degrees. I was going to try it on 12 btdc but I don't think I wll bother now I will just leave it on the std 15btdc and see how we go from there.
Cheers.....Tony..