When Lightspeed put my engine together they are going to time it as near perfect as they can. I don't have cam locks.

When I originally fitted them Barbz marked them with TDC positions for me.

From the C&B website I got the following specs of the cams:

Intake
F5T.102.280S.A
10.2mm lift
280 degrees duration
Timing 16-84 (with phase variator opened 41-44)
Lobe center angles 124°
Lobe center angles with phase variator opened 99°

Exhaust
F5T.094.260S.S
9.4mm lift
260 degrees duration
Timing 60-20
Lobe center angles 110°
Lobe center angles with phase variator opened 110°

I assume that by "Lobe Center Angles" they are referring to the centreline and not lobe separation angles. This makes sense given that the exhaust centre angle doesn't change whether the phase variator is open or closed.

To time the engine at TDC can I find the point on the exhaust cam that gives maximum lift using a dial gauge and treat this point as 110 degrees BEFORE TDC?

For the intake cam do I find the point on the intake cam that gives maximum lift using a dial gauge and treat this point as either 124 or 99 degrees AFTER TDC?

When the engine is being timed off the car do I treat the variator as open or closed?

What do they mean by timing 16-84, 41-44 and 60-20?

Hi,

Given values for the C&B cams do not match with the reality!
We have measured mine and my friends C&B cams and they are not even a close to given values, if measuring the duration like Fiat does (0.45 mm valve opening).
Secondly Coupe engine does not have 25 deg cam variator like C&B claims.
Thirdly you never get the claimed overlap values with those timings.

We made our own timing without cam locks through crank shaft degrees.

But all in all the C&B cams gives a huge power increase and engine behaviour. My friend got 35 bhp power gain with only changing the cams, 378 bhp => 413 bhp.

- Jari-

Hi Jari,

Did your friend remaped the car after fitting C&B cams? Or did he got these +35hp with the same eprom?

Looking at the timing diagram for the standard cams in the workshop manual I can see what the C&B figures of 16-84, 41-44 and 60-20 mean.

For the intake the first figure represents how many degrees BTDC it opens, the second figure how many degrees ABDC it closes.

For the exhaust the first figure represents how many degrees BBDC it opens, the second figure how many degrees ATDC it closes.


For standard cams the exhaust figures are 40 - 0 giving a duration of 40 + 180 + 0 = 220 degrees and a lobe center of 110 degrees BTDC.

For the intake they open 8 degrees ATDC and close 54 degrees ABDC giving a duration of 172 + 54 = 226 degrees and a lobe centre of 121 degrees (226 / 2 + 8) ATDC.

With the phase variator they open 10 degrees BTDC and close 36 degrees ABDC giving the same duration of (10 + 180 + 36) = 226 degrees and a lobe centre of 103 degrees (226 / 2 - 10) ATDC.

You are correct in that the phase variator shifts the intake cam by 18 degrees not 25 as C&B claim.

The timing figures for the C&BG don't make sense either. The 16-84 gives a duration of 16 + 180 + 84 = 280. However the figures with the phase variator are 41-44 giving a different duration of 41 + 180 + 44 = 265 which is impossible!

How do you suggest I time the C&B cams!! I can find the lobe centres but how do I know how many degrees BTDC the exhaust should be set to and how many degrees ATDC the intake should be set to?

Hi Pierre,

Yes, just the cam change. Power before and after cam change. All the other "parameters" were identical.

- Jari -

Hi,

The timing depends on a little bit what you are looking for. Low down torque or high rev power, with cam timing you can "manipulate" these things quite good.

Send me your email address and I will send you a written memo (in english) of my cam change with measurements of OE cams and C&B cams. I can send also couple pictures of the cam change.

-Jari-

please send to me to..
hcatita@hotmail.com
cheers

John GC site explains this, and the degrees are CRANK degrees!! look here http://www.guy-croft.com/viewtopic.php?f=3&t=213 msn me some time and I'll tell you how.

You can make a locking tool for the cams. They are slotted at the far end, so cut out holes in a piece of flat metal to go round the last caps and lock both cams so the no 1 lobes are facing opposite each other. This should be done when cyl 1 is at TDC according to your dial guage (there is a specific Fiat dial gauge which I have but any will do as long as you can ensure it really is TDC).
I got the locking tool with my cams but later people who ordered did not.

Once you have lined it all up lock the vernier adjustments on both cams
They should NOT be timed in with the Cam caps as that will be wrong.
You can adjust them and mine are not exactly to ythe original C&B spec.

Right I think I getting closer to the bottom of the timing of the C&B cams. I've been in email contact with C&B and Mr Bariani thanked me for pointing out the mistake on their timing information. It should be 16-84 and 41-59 not 41-84. They claim the variator does infact shift by 25 degrees not 18. Therefore the 16 becomes 41 and 84 becomes 59.

Reiterating the original FIAT intake timing:
With phase variator on the timing is 10-36. So opens 10 BTDC and close 36 ABDC. This gives a duration of 10 + 180 + 36 = 226 and a lobe centre of 103 degrees (226/2 - 10).

With phase variator off the timing is retarded to 8-54 where the 8 is ATDC and 54 is still ABDC. Gives a duration of -8 + 180 + 54 = 226 and a lobe centre of 121 degrees (226/2 + 8).

For the C&B camshafts:
With phase variator on the timing is 41-59. So opens 41 BTDC and close 59 ABDC. This gives a duration of 41 + 180 + 59 = 280 and a lobe centre of 99 degrees (280/2 - 41).

With phase variator off the timing is retarded to 16-84 where the 16 is BTDC and 84 is still ABDC. Gives a duration of 16 + 180 + 84 = 280 and a lobe centre of 124 degrees (280/2 - 16).

So you can see the lobe centres of the FIAT cams and the C&B cams are pretty much identical, within 3 or 4 degrees of one another. However the C&B cams have a much larger duration, 280 degrees compared to 226 degrees.

The thing that still puzzles me is the C&B timings assume that the variator shifts by 25 degrees. If it only shifts by 18 degrees as in the FIAT timings then the lobe centres of 99 and 124 are too far (25 degrees) apart. They could be timed to be the same as the FIAT cams, moving them both closer together at 103 and 121. The alternative is to keep one the same and move the other. For example keep the 124 but retard the 99 to 106 which would make the low rpm range of the engine more lumpy. Or keep the 99 and advance the 124 to 117 which would reduce high rpm power.

Now the interesting thing is that Barbz has both the original FIAT cam locking tools and the C&B cam locking tools. He set the C&B cams up using the C&B cam locking tools then tried the FIAT cam locking tools to see what the difference was. The exhaust was identical but the intake on the C&B was about 5 degrees advanced compared to FIAT. This would indicate that the answer is somewhere in between. Advance the C&B figure of 124 to 116 (121 - 5) which therefore retards the C&B figure of 99 to 104 (99 + 5).

These cams are giving me a real headache to know how to time. I remember them being very difficult to get to once the engine is installed with the cam cover in place. Therefore I don't think it's going to be easy to play with different degrees.

The exhaust cam isn't an issue we've timed it in to 107 degrees which is as close as 110 we can get without an adjustable exhaust pulley.

The standard FIAT intake cams lobe centres are at 103 and 121 (variator off). The C&B cams have lobe centres at 99 and 124 (with variator off). However C&B assuming that the variator adjusts by 25 degrees which is wrong, it only adjusts by 18 degrees.

We're thinking of using 120 degrees (variator off) giving 102 degrees with variator on. We didn't want to go lower than 100 degrees. Neither did we want to to too high because with forced induction it's not necessary to leave the intake open for too long ABDC. These figures also bring us very close to the original FIAT figures.

Any thoughts? Is 120 degrees going to make it too top end?

John

Maybe they expected us to fit a non-turbo VIS or later variator along with the cams as they move 25 degrees I believe. I have not compared but have a couple of Stilo abarth variators in my garage and I'm pretty sure they move further.

I would just wind back the variator and time it as per the C&B standard. If anything I would go the other way and make it less top-end as 90% of the time you probably aren't using the top end anyway.

Hi John,

Would you recommend something more like 116 degrees and 98 degrees?

On the C&B website they say they design their cams to be set up using the factory marks. However when Barbz compared the positions of the intake cam using the FIAT locaking tool and the C&B locking tool the C&B position was actually 5 degrees advanced over stock (121 - 5 = 116).

John

Mine is timed with the C&B tool, then I believe the inlet is advanced a couple of degrees and exhaust retarded a couple of degrees if I remember correctly. Short of taking my rocker cover off I cannot remember exactly

Hi, I've imported this cams to Brazil 2 years ago and since then I've never succeded to make them work because of this locking tool.

With the FIAT locking tool, I lost my brakes and the engine had no idle. So I've tried to advance the exhaust cam 2 degrees, brakes returned, idle to, but lost 10whp.

Since then I've give up.

Reading this thread again, I could see a light at the end of the tunnel.

JohnS, can you make a copy of your tool and sell it to us?

Tipoboy, can you find this tool and make a copy to you and me? Of course, I'd pay for that....

It is much easier if I tell you how to make your own tool!

Just get a piece of steel
60mm width, 250mm length, 1mm thickness.
push the piece of steel up against the end of the cylinder head beyond No. 5 and it will not reach the cams because the last two cam caps are in the way. Mark where the cam caps are and cut them out of the piece of metal leaving say 15mm intact so you still have a single piece covering the whole width of the cylinder head. You now have an exact copy of the C&B cam locking tool!!

Look at your C&B cams - at the other end to the pulley end they have a slot. This slot is on both inlet and exhaut cams and is the timing slot. You are NOT supposed to use the Fiat locking tools - if you do you will end up timed up wrong. if you do not have these slots they are not C&B cams (I think there are some copies out there) and you may not be able to time them up without getting someone with genuine C&Bs to measure the degrees offset to the fiat locking caps.

Now the piece of metal will touch the ends of the cams. There are two slots at the end of the cams. Move the engine to TDC on No.1 then put the cams in with the inlet and exhaust pulleys unlocked. The orientation of the cams is roughly that on the first lobes on No. 1 the two peaks of the lobes are facing directly away from each other. Now the cams will be slightly out when you look at the slots at the other end of the cams so use the tool you have just created to insert into both slots at the end of the cams; ensure the tool is not bending when it is sitting in both. They are now timed up as per C&B standard. Now put on the belt and tension as normal, locking the pulleys back up as you do it


Lovely.

John

Finally, like Leighton advised me a few weeks ago, the 2 slots need to be face to face and parallel to the cylinder head and in this case you don't need the locking tool

If i have correctly understood

yes you have! The tool makes it more accurate as it is difficult to be visually sure. You could just get a plastic ruler and cut a couple of bits out of it and do it that way

Thanks John! Good news! I think i'm going to search for a set of C&B with slots in a few weeks

In fact i understand very quickly, you just need to explain me 10 times and that's ok

This is a picture of my C&B cams. Is this the slot you've mentioned?

http://img.photobucket.com/albums/v237/weiler/cams/ComandoMarea033.jpg

http://img.photobucket.com/albums/v237/weiler/projetok24/camshafts1.jpg

http://img.photobucket.com/albums/v237/weiler/projetok24/camshafts.jpg

Cheers.

No, look at the other end of the cam !

Can any one post a photo for the cams adjusted!!

Maybe I was unlucky but the slots where slightly off on mine.

Oh! Jesus, open my eyes!

Maybe here:

http://img.photobucket.com/albums/v237/weiler/cams/ComandoMarea034.jpg

http://img.photobucket.com/albums/v237/weiler/cams/ComandoMarea029.jpg

http://img.photobucket.com/albums/v237/weiler/cams/ComandoMarea028.jpg

or here:

http://img.photobucket.com/albums/v237/weiler/cams/ComandoMarea025.jpg

There are some C&B cams doing the rounds that don't have the slotted ends. If you have these, which it looks like you do, then you really need to get some C&B locking tools otherwise you can't be sure they are setup correctly. You can use the standard cam locking tool on the exhaust side but the inlet is quite different.