Cam Phasing
- Thread starter Bodyperson
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TT5.9mag
Two atmospheres are better than one
No, actually.
We are talking about 2 different operations. I am centering a cam from a cam card. You are talking about degreeing a cam. They are different operations
BSB67
Well-Known Member
To the OP, your wording is incorrect, so we’re concerned that you might not have it right. Possibly when you are using the word “separation” you actually mean “centerline”.
If you have an old chain set, I’d be inclined to use it.
If you have an old chain set, I’d be inclined to use it.
Thanks, that clears things up for me.
In today's "modern" engines, a key simply locates and is not intended to carry any shear loads. The bolt stretch provides clamp load which creates a joint held in place by friction.
I wouldn't know what our forefathers designed "back in the day" on these old engines. I doubt they used the key to carry shear but I wasn't there (I'm old but not that old!).
I have used offset keys in the past to get a cam degreed where I wanted it. Sometimes an offset key and a tooth off in the other direction - whatever it took to get the proper centerline. I've never had any issues with offset keys but IIRC the most I used was a 4 degree key. FWIW.
Yeah, it wasn't about pointing out mistakes. It's about trying to help him get the thing right. The way he worded it made it sound like he wasn't sure what was goin on.
I'm off half a bubble for sure.
I'm just going to trust Bullet Racing. They get pretty good reviews. I was just wanting to get opinions on the off-set key idea. I did do some dry measuring.
I'm gona add this, just so you don't get misled as to what's what for degrees. post 176 has more info
Cam degreeing help me understand!
Me, I'd rather use a t-set with one of these in it.
Cam degreeing help me understand!
Me, I'd rather use a t-set with one of these in it.
junkyardhero
Well-Known Member
you have it all apart! why not verify the grind and confirm the install *before* you order a key or timing set you may or may not need?
rule number one: never trust a blone with hoop earrings
rule number two: trust but verify
it's not like it's any more work! or hard work! and it's right there!
also, i'd check the chain for slack against the proceedure in the FSM. i'm not a betting man, but i'd lay a slice of ham that it's beyond spec. or just go wholesale r&r the thing with one of them summit billet jobbers that's got adjustable key ways. two birbs, one hammer, in hand.
rule number one: never trust a blone with hoop earrings
rule number two: trust but verify
it's not like it's any more work! or hard work! and it's right there!
also, i'd check the chain for slack against the proceedure in the FSM. i'm not a betting man, but i'd lay a slice of ham that it's beyond spec. or just go wholesale r&r the thing with one of them summit billet jobbers that's got adjustable key ways. two birbs, one hammer, in hand.
If it was any tighter, I could not install it and that's with aligned hone and decking. Mopars rock!!!
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Only if you want to run it where the cam grinder recommends to.
Actually to run it where he recommends, your other parameters need to match up as well''' Like specified usage, cylinder pressure, gears, and stall.
Just cuz the cam card says plus 4* doesn't mean that's what is best.
For example;
My engine has a clutch and a preponderance of cylinder pressure , So I don't need the cam-advance. I'd rather give those 4* to the powerstroke, and increase the potential for fuel-economy.
When you get down to basics, every cam has it's own signature of total number of degrees that are available for Compression and Power-extraction. Typically, you might see 230 degrees. And typically you might see 125* to compression and 105 to power. But, if you already have more compression than you need , then you can give some degrees to Power extraction and pick up some efficiency and with that, usually comes more MPG. If your engine spends most of it's life racing, you might sacrifice some of that 105 Power and give to Compression cuz Pressure is heat is torque is power.
At best from 4*retarded to 8*advanced is your window, any more than that is gonna start killing your Overlap cycle and that spells a powerloss, throughout the rpm band.
Putting the cam in at +4*, on a split-pattern cam, generally, will center the overlap. , and a well-placed overlap, generally will produce the most average power in third gear, where the race track wants it. But on the street, that is not always the case, especially with a torqueflite that drags the 1-2 shift down to 59%. From 5500 that drops to 3245, and if your torque peak is not until 4000, well, that's crap. So that's where your Cylinder Pressure better come on line, and your Overlap better come alive. That's where the 4* advance van pullup your bottom end. But............ if the pressure puts you engine into detonation, then just maybe that 4* is too much, and now you are forced into buying the next higher octane gas. Which for the other 95% of the time is way more octane than you need. which just drives your cost per mile up, needlessly.
So, you asked
Answer, IDK
need more information.
pishta
I know I'm right....
Ive seen oil drive hex worn almost round and all that torque runs through that keyway. Had SG rear axle splines twist almost a full spline right out of the carrier, stuff happens.
So are you implying that the crank gear wobbles around on the crank snout ? Whats the clearance difference between the 3 ? I have torn down many 100,000 mile engines and don’t recall any weith wear . Crank or cam ….
pishta
I know I'm right....
Huh? Never mentioned crank gears......But I do have a Milodon gear drive with a crank gear... ?
Both use keyways
TT5.9mag
Two atmospheres are better than one
If the shaft is straight (not tapered) and the gear has no press fit, the key carries the sheer load. I agree with you, they do work. I was merely stating I personally have never trusted them.
There is no guarantee that the cam 4* advanced is going to produce the desired power curve. Pick a number & bolt it up. Then dyno the engine if desired, & adv or ret the cam, to get the desired curve.
Y' all think that the factories degreed each cam on the hundreds of millions of engines they built?
Y' all think that the factories degreed each cam on the hundreds of millions of engines they built?
You didn't miss anything. Well, maybe the original post.
"Is the off-set woodruff key for the camshaft itself an acceptable way to adjust the phasing?"
If you really want to know the specs, come on over. I'll provide food and drinks.
Fairly mild grocery getter.
Newbomb Turk
Well-Known Member
Big difference between an OEM building several hundred thousand units and someone building a performance engine.
Not even close.
To even advocate that it’s acceptable or even ok to just slap the timing set on and go is bad advice.
jos51700
Green Bearing thread connoisseur
That's not really how it works....
Modern engines, my foot. (other than that, DemonX2 is 100% right).
The key was never designed to carry load, ever.
The sprocket bolt that clamps the cam sprocket to the cam is what makes the spinny-magic happen. The clamp load from sprocket to cam is what locks the two together. I ain't doing the math but there's hundreds of pounds of force holding the cam to the sprocket when the bolt is properly torqued.
The keys are supposed to be weak. If something goes south, the intent is to shear the key and not eat up the nice expensive components (although on a small block Mopar you're likely going to trash the valves if this happens).
The key is an alignment aid only and carries no, I repeat NO load.
Newbomb Turk
Well-Known Member
You didn't miss anything. Well, maybe the original post.
"Is the off-set woodruff key for the camshaft itself an acceptable way to adjust the phasing?"
If you really want to know the specs, come on over. I'll provide food and drinks.
Fairly mild grocery getter.
They work fine. It’s all we had before these 9 keyway sets that confuse most people.
I’ve used them with roller cams and shifted that engine at 8k for two years. It never failed.
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