@@staceonwheelsI have to hold myself back. If I make something to good,then that starts a ball rolling and makes everything else looks crappy. Darn rabbits..
Hi Stuart, nice to see you back again. Yeah the comments here and on other videos are almost always really constructive. I've changed the crank gear and redialed the cam and it's spit on now.
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!
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. All in the name of pollution.
Well that's interesting. I had heard they retarded the timing... I'll think about how that could relate to this... as I was sure the cam and crank were both for the earlier 308 I have.
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.
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. Also, just another little tip - when you're looking for TDC using bump stops, it's better to use longer bumps - about an inch or two long rather than a few mm. If you think about the geometry of the crank, when the piston is very close to TDC the crank turns quite a lot for a tiny difference in piston height, so any small deviations give you a bigger difference in measured crank angle. By stopping the piston an inch or two down from the deck, any tiny errors in piston position relate to much smaller errors in crank angle. I don't think this would be the cause of your 5 degree error though, but still something useful to keep in mind.
Thanks for the tip. Yeah from the videos I've watched no-one else get anywhere near 5 degrees out. And Gary himself had never seen 5 degrees either. Atill a mystery but maybe continuing with the build could reveal something. Or not 🤣
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
Very encouraging, thanks! I didn't expect this amountvof timing variation but seems it's not too out of the ordinary. You're right, I can just keep experimenting!
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.
Thanks! Yeah I have retarded it 4 degrees. Fingers crossed it works as planned. I'm estimating closer to 10 for compression, with the pistons I have and the decks having been machined a little, but plan to calculate it.
@@staceonwheels yep quality control wasn't great back then stace even the red holden six cylinders were the same mid 70's 253 and 308 in lx toranas were known for bad cams
looking forward to the next video 👍
Fing rabbits, always drag me down that bloody hole. Or is it me, looking down there. Nice one.
Haha! Sadly true.
@@staceonwheelsI have to hold myself back. If I make something to good,then that starts a ball rolling and makes everything else looks crappy. Darn rabbits..
@benjohnson7170 ha! Yes I understand your problem.
This is a great video
And i think i was your 1000th subscriber too
Yes you were! Welcome, and thank you!!!
Excellent video Stace, and some really great comments below. Hopefully your next video will have it sorted with the -4 degrees.
Hi Stuart, nice to see you back again.
Yeah the comments here and on other videos are almost always really constructive.
I've changed the crank gear and redialed the cam and it's spit on now.
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!
Drum brakes always are a mess!! Do you have that special spring tool that makes it easier?
Ordered one on Friday after slipping off with screwdrivers and some cursing. 😎
@oo0Spyder0oo 🤣🤣🤣
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.
All in the name of pollution.
Well that's interesting. I had heard they retarded the timing... I'll think about how that could relate to this... as I was sure the cam and crank were both for the earlier 308 I have.
NO way such a big drop.
I should have said this relates to before the VN heads came on the scene, try the book "How to hotrod a holden v8" lots of info there.@@staceonwheels
Thanks, I have that book already!
Smart girl
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.
Yep Gary does know all that. But I cannot yet understand how 5 degrees only changes behaviour at low RPM and not elsewhere in the RPM range.
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.
Also, just another little tip - when you're looking for TDC using bump stops, it's better to use longer bumps - about an inch or two long rather than a few mm. If you think about the geometry of the crank, when the piston is very close to TDC the crank turns quite a lot for a tiny difference in piston height, so any small deviations give you a bigger difference in measured crank angle. By stopping the piston an inch or two down from the deck, any tiny errors in piston position relate to much smaller errors in crank angle. I don't think this would be the cause of your 5 degree error though, but still something useful to keep in mind.
Thanks for the tip.
Yeah from the videos I've watched no-one else get anywhere near 5 degrees out. And Gary himself had never seen 5 degrees either.
Atill a mystery but maybe continuing with the build could reveal something. Or not 🤣
Should be using solid lifter to test not a soaked in oil lifter which doesn't do anything?
I did switch to an old locked up lifter which didn't compress.
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
Very encouraging, thanks! I didn't expect this amountvof timing variation but seems it's not too out of the ordinary. You're right, I can just keep experimenting!
accumulation of small errors which is all adding
Yeah, sounds plausible. Thanks.
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 .
I'll ask my machine shop what they reckon, they already did heaps of work on it anyway!
How much has being decked off of your block
Not sure exactly but it was very minimal and just to clean up the surface.
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.
Thanks! Yeah I have retarded it 4 degrees. Fingers crossed it works as planned.
I'm estimating closer to 10 for compression, with the pistons I have and the decks having been machined a little, but plan to calculate it.
Interesting
Frustrating!! 🤣
mass producing so they probably didn't worry too much about the accuracy
given its not going to be a racing engine it will be ok
Do you mean Holden, when the set the keyway on the crank? Because yes, that's a good argument why 👍.
@@staceonwheels yep quality control wasn't great back then stace
even the red holden six cylinders were the same
mid 70's 253 and 308 in lx toranas were known for bad cams
You are being too pedantic, 5 deg adv will improve low end torque and compensate for chain stretch .
Thanks. But how much will it change the rest of the rpm range from what I chose the cam for?