Guide to timing my sigma 150 -also useful for 140 supersport

[pilotprice]

Just fyi

This timing was confirmed once more by caterham and one of there techs who does the supersport support for the race series


My car was finished and ran 153hp on the local rollers

[Eccles52]

I had forgotten about this thread but I had my 110/110 confirmed by Caterham too so fair to say the cams in my 150 are different cams to the supersport ones you have then

Mine are by Piper Cams and with an inlet lift of 9.1mm and those timing figures makes them their Ultimate Road cams.

Good power too mine only saw 142 on the rollers which I think was quite good for the 150.

Of course, if they are the same cam that's a free 10BHP next cam change (if not before)


Ivan

[mharris]

I didn't really follow, so what was the conclusion here..? That you both have different cams in your 150s or that Caterham have given out conflicting advise?

[Eccles52]

I'm not too sure to be honest I suspect we have different cams (8 degrees sounds too big a difference for the same cam to work well at both). I got in touch with Piper and they couldn't discuss cams for other manufacturers but I hope to get the rocker cover off sometime and measure the lift and duration of the ones I have to see if they are the Ultimate Road cams that Piper list. Ben's figures are certainly right for him as he is seeing 11BHP more than me.

Ben, did you buy your cams as 150 cams or Supersport ones and any ideas on the manufacturer/lift/duration?

Ivan

[Eccles52]

Had a very useful answer on BC, we could both be right with our timings as it it looks like they are both right it just depends on what induction system you have. The dual throttle bodies favour the 110 inlet timing and the longer supersport system favours the 118 degrees. But it seems the cams are the same.

[pilotprice]

Hi all

Hopefully we can get to the bottom of this! (Ivan I saw you post on BlatChat, but I'm not a member)

Just to clarify a few points -

My cams were bought from Caterham and arrived from piper in piper boxes as "150 Spec" they have "150" marked on the end of the shafts and came with single, HD springs.
I'm of the understanding that the 140 and 150 uses the same piper cam profile
I DTI'd an supersport engine prior to my works and got 110/111 inlet and 118 exhaust.
The standard timing is about 110/111 for the inlet and the ford tool will slot in the hole, I'm not sure what the exhaust standard timing is
The piper site states the ultimate road cams timing at 110' 110' but we know Caterham don't use this timing for the 140?

I have had the 140 cam timing confirmed at 111 and 118 and these match the results from the engine I took readings from before doing mine.

I'm 99% confident that the 140 timing is 111 118, the only way my engine is wrong is if Caterham changed the timing to 110/110 for the 150?

I'm on a different set of rollers at the weekend and will report results with a few pictures

[pilotprice]

As promised here are the results from another RR run today (after a cheeky blat round NW)

Results were as follows -

149.6 bhp at 7260 rpm ( 123.6 at wheels )
119.6 left at 6300 rpm (99.4 at wheels)

AFR - nice fuelling through from 14.0 to 12.4

Looking at the graph it would suggest that 111 118 is the correct timing for MAX bhp, however retiming to 110 110 may give more mid range and less peak power.
Im going to re time to 110 110 and see what I get in a few weeks



To give a benchmark, my mates supersport 140 ran 142hp with 118 lbft at the RR also

Ill post a video and graphs now off my phone for you guys

[pilotprice]

https://youtu.be/9xCv5-c6vkU

[mharris]

Nice, it'll be very interesting to see the difference. Perhaps some adjustable cam pulleys would have been a good investment at this point

Does it take you long to change the timing? Id always assumed it was a big job. Would love to check my 150 but dont really know what I'm doing.

[pilotprice]

Technically the standard pulleys are adjustable as they are not keyed, they don't however have marking on to advance or retard.

The process is just as the guide I posted, will probably take 2/3 hours from 'brew to brew'

[Eccles52]

Great to see those results Ben
Certainly seems to be that the 140 cam is the 150 cam, making the only differences between the 150 and 140 the inlet, throttle bodies vs plenum and cam timing.
Mike on BC found that running 110 timing gave a little more power than the 118 setting with the throttle bodies that we have so will be great to see your results at that.
It certainly seems that Caterham time the 150 at 110 and the 140 at 118 from our questions

I think I've decided that I'm going to take mine for a re-map to improve drivability and see what else there is at the top end over the summer and will post my results when I get them. Ben, did you have the map flashed to the 150 or a full re-map on the rollers?

Ivan

[pilotprice]

I posted my MBE ecu to caterham and got them to flash the latest map.

I don't seem to have any drivability issues which others experience, my MAF is disconnected and I think I have the latest flash. My graph is pretty progressive with significant dips.
From memory, cc charged £75 inc vat for the flash!

[Eccles52]

Admittedly the drivability isn't bad but could be better - mind you, I haven't balanced the throttle boddies for a couple or four years so that may well help.

I spoke with Caterham this morning and there is only one map that has the MAP sensor disconnected and that's the latest one so yep, we've got the latest map

[pilotprice]

Ok, little update!

Firstly the timing -
As promised, I have retimed my engine to 110' 110' and I'm booked in for the RR on the weekend. I made a timing tool out of a C spanner to save me the faff in setting up the DTI and timing disc again if I lose power! The inlet cam was reading 110.5 111 over several recordings so I'm happy to leave that to within 1' of spec.

I took some pictures of the timing before and after.




The timing at 111' 118' is as follow, the inlet cam is horizontal parallel to the head and the ford timing bar will slot in, the exhaust cam is retarded and required the timing tool to be formed as pictured.






The timing at 110' 110' is inlet horizontal parallel to the head and the exhaust cam is slightly advanced to the parallel, I think this is to do with the difference in valve angle on the exhaust side.





So, lets see what the results give at the weekend!





Also, I have changed my diff (what a pig to do). The old diff was found to be a 3.69 after removing the back plate (thank you old owner! I'f you're reading this, also you didn't tighten the prop bolts and you stripped the OS cap nut!!)
Car now has a 3.92 ready to rock!

Also fitted a Vibratronics gearbox mount too as I don't like the amount of powertrain movement under load

Edited by pilotprice on Thursday 4th August 11:13

[mharris]

I'm thoroughly confused here..

I thought it is the timing of the inlet that we are questioning - either 118 or 110..?
It appears from your pictures and text that you've left the inlet cam alone (because it was within half a degree) and re-timed the exhaust cam.

Your before and after pictures show the exhaust cam moving a noticeable amount whereas the inlet doesn't. Surely it should be the other way around?

Edited by mharris on Thursday 4th August 15:10

[pilotprice]

Yep, you are correct.

I'm a complete buffoon. I have timed the engine 110 inlet and 118 exhaust. FFS
Great recipe for 150hp though lol.
Ill have to start over now

[mharris]

Ahh thats gotta be frustrating!

Anyway 149 is still impressive for a mis-timed engine. Although the chap on blatchat did say that the exhaust timing didn't really make any difference.

[pilotprice]

Update -

Apologies for the confusion here! Please see below -

The engine was timed at 118 inlet and 111 exhaust beforehand.
Yesterday I mistakenly timed the exhaust cam thinking it was at 118 and not 111 and advanced the cam 8 degrees! I also was doubly confused as I had timed the engine yesterday anti clockwise!


So

Today I have re timed the engine to 110 inlet and 110 exhaust, the original 149.6hp bench mark still stands at timing of 118 inlet 111 exhaust

Off to the rolling road

[pilotprice]

Update -

Apologies for the confusion here! Please see below -

The engine was timed at 118 inlet and 111 exhaust beforehand.
Yesterday I mistakenly timed the exhaust cam thinking it was at 118 and not 111 and advanced the cam 8 degrees! I also was doubly confused as I had timed the engine yesterday anti clockwise!


So

Today I have re timed the engine to 110 inlet and 110 exhaust, the original 149.6hp bench mark still stands at timing of 118 inlet 111 exhaust

Off to the rolling road

[pilotprice]

Just took it for a drive, obviously have a 3.92 diff now and aeroscreen so can't comment too much, however I would say the engine feels less zingy and more how can I say, boggy?

Looking forward to the rollers