Aftermarket Camshaft Timing

[dandan]

OK guys,

 

These questions are aimed at all of you who have aftermarket cams and adj cam gears fitted... (basically I am wondering what sort of cam timing on what cams, let's say HKS 256I/264E for example on a single or maybe even BPU, has given an optimum torque curve).

 

Have any of you actually timed the cams in 100% by using a dial gauge to find TDC and then using a cam wheel to set the cam exactly as recommended.

 

Further to that has anyone had their motor on a dyno or rolling road and adjusted cam timing to get their optimum torque curve from that initial setup?

 

It seems to me a lot of people fit the cams and leave the cam gears at zero and call this - "zero". Similar to a lot of the young guys on SF do when they fit cams, they then start saying..."+1 on the intake and -2 on the exhaust did xyz" then someone else goes off and does the same. Well given the manufacturing tolerances on the cams, crank, gears, belt etc these two motors probably won't be timed the same at all and yet people seem to think they are.

 

So who has dialled their cams in properly to the HKS/JUN/BC timing sheet and have you found any benefit in advancing or retarding from there on your particular setup?

 

Cheers

Dan

[tDR]

I remember a looooooooonnnnng time ago a post by Terry S saying he and Leon had done this on his purple car but after lots of fannying about trying different settings that stock cam timing offered the best blend of power / torque / driveability so they stuck with that and the recommendation was not to bother with cam gears due to this.

 

Cheers,

 

Brian.

[Nic]

I have in256 ex 264 with GT35R single, mine were set up on the dyno but I don't have a record of the settings. Next time I have the engine cover off I'll check and post settings here.

[Ian C]

I got some Jun adjustables to test that inverse stagger setup, but when going back to the 256/264 setup I just put them to stock. Didn't dial them in or owt.

 

Before fannying around with the settings I'm trying to understand what it affects and why, and it's a nightmare!

 

-Ian

[dandan]

I got some Jun adjustables to test that inverse stagger setup, but when going back to the 256/264 setup I just put them to stock. Didn't dial them in or owt.

 

Before fannying around with the settings I'm trying to understand what it affects and why, and it's a nightmare!

 

-Ian

 

Did you dial in the staggered setup exactly as per Chris' (poggie on SF) recommendation? From speaking to Chris the timing is uber important in this setup or there are substantial losses to be made

[Chris Wilson]

If people supply or buy adjustable wheels I dial the cams in if they so wish. It's a nightmare with the engine in the car though, very time consuming and fiddly. A set of stock wheels with HKS cams seems to be very close to spot on for a road engine anyway. Out of the car it's no big deal, adds about two hours to the build time of an engine.

[Ian C]

Did you dial in the staggered setup exactly as per Chris' (poggie on SF) recommendation? From speaking to Chris the timing is uber important in this setup or there are substantial losses to be made

 

I set the wheels as he said but I didn't dial them in to account for manufacturer error.

 

I'm unconcerned by this as a) you won't see measurable differences with cam timing until you start shifting things in 2deg increments, b) the most a manufacturer is out is around 4deg, and c) I can't believe there is a +XXbhp sweet spot that if you move 1deg in any direction on either cam it turns into a -YYbhp dog. As romantic as it sounds, engines just don't work like that.

 

-Ian

[Wez]

If people supply or buy adjustable wheels I dial the cams in if they so wish.

 

Do you dial them at bang on what Toyota says or something else?