Dialing In The 308's Cam Reveals Timing Troubles

It was going to be a simple learning exercise, to dial in the cam and test the piston to valve clearance of my 308, before starting assembly. But just as well we did it, because dialing in the cam showed up a problem with timing... instead of being 2 degrees advanced, as per the cam's grind, we found 5 extra degrees advance. Where it that extra 5 degrees come from?
LINKS…
Better Engine Building: The Easy Way to Degree Your Camshaft: • Better Engine Building...
How to Degree a Camshaft: Lobe Center Method: • How to Degree a Camsha...
CREDITS…
Thanks to Evan Splash for the theme music Drive It Now, provided by Tunetank at: tunetank.com/track/429-drive-...

[@lucasvyner1502]

No you are absolutely right to be that particular on 5 degrees.That's enough to have valve/piston clearance issues or all kinds of timing problems to sort out later depending on your setup........

[@PhunkBustA]

looking forward to the next video 👍

[@stuarterskine7745]

Excellent video Stace, and some really great comments below. Hopefully your next video will have it sorted with the -4 degrees.

[@NoDiarrhea007]

This is a great video

[@benjohnson7170]

Fing rabbits, always drag me down that bloody hole. Or is it me, looking down there. Nice one.

[@oo0Spyder0oo]

That engine looks great, good on you for tweaking it, it will pay off. I’m replacing the springs, brake cylinder and shoes on the rear and it’s a confusing mess!

[@cameronjohnston5748]

Hi Stacey, Something to think about is the differences between the prepollution engines and the later pollution ones was that the cams were ground the same specs but they changed the cam timing by shifting the keyway in the chain set, which keyway I am not sure. I think it was a 5 degree shift and that caused a power drop from about 240 HP down to 160 ish hp.

[@timevans9710]

Tolerance stack up is your issue, a half a degree on your crank and a one degree difference in your chain set all adds up. Do what your viewer said and try the -4 keyway, if you are still a little off get yourself an off set crank key which you can get in1 degree increments. I would personally ran it at 4 degrees advance anyway, as it will boost low end torque without reducing your top end power to much,, which is needed on a small V-8 such as yours. Your engine guru should have known all this anyway.

[@bigblockpop]

Smart girl

[@RVK355]

accumulation of small errors which is all adding

[@sharkskinboy]

I'm surprised the motor doesn't have anything on it to adjust cam timing. On SB Chevys you use offset bushings, you press the appropriate one into the cam gear hole that the cam pin locates into, and that adjusts the timing as you please. I don't think you can adjust it 5 degrees though, that's a lot. The most I ever heard of is 4 degrees.

[@gerryphillpott3249]

Your crankshaft if reground can be reground slightly offset to remove the worse part of a bit of wear by a machine shop not by much but enough .

[@oz2263]

Hello Stace, just found your channel and can sympathise with you frustration with cam timing on Holden's, if you're after the best performance from a crow cam just read the cam card and set it up to have the specified lift at no 1 inlet at tdc and it will be good, in the past I've had to advance a full tooth and then use the retard gear keyways to achieve this figure, not good for the next guy working on it but best for the cam. At least your not working on an old Ford cleveland they are much worse. Hope it all works out and if it doesn't you can make more vids on changing the cam timing and the perceived changes a few degrees of timing makes to your engine. Cheers

[@kymelefsen5276]

Should be using solid lifter to test not a soaked in oil lifter which doesn't do anything?

[@kymelefsen5276]

How much has being decked off of your block

[@bigal878]

Good video and I’ll been keen to see what you find when you retard the cam 4 degrees. I can’t see you needing to chase this anymore than 4 degrees, 2 degrees might do the job to for a 308 noting the cam you are using a 230/230 @ .050, approx .500” lift (pretty much a 286 Crane) cam. How much compression is this 308 engine going to have? The engine will need some compression (at least 9.5 to 1. 10-1 would be better) to mate the cam work and you might find it will want to rpm higher than you want, but the early style heads with absorb some cam compared to VN style with the same spec cam to suit the different valve layout. Anyway, good luck.

[@drifterdrifter9558]

Interesting

[@GeeenJ]

mass producing so they probably didn't worry too much about the accuracy

[@markw5766]

You are being too pedantic, 5 deg adv will improve low end torque and compensate for chain stretch .