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Cam Correct Variable Cam Timing

13K views 27 replies 9 participants last post by  cobalt327 
#1 ·
#2 ·
I talked with the guy that designed it- I wouldn't run it. It kind of does do what it says it does, but it only does under engine acceleration AND it messes with your ignition timing. If I was running a crank trigger ignition and a good FI system it may be worth looking into but WAY too hard to tune with a dizzy and a carb.
 
#3 ·
ap72 said:
I talked with the guy that designed it- I wouldn't run it. It kind of does do what it says it does, but it only does under engine acceleration AND it messes with your ignition timing. If I was running a crank trigger ignition and a good FI system it may be worth looking into but WAY too hard to tune with a dizzy and a carb.
Please explian how this item (messes with ignition timing).

sam-missle
 
#4 ·
sam-missle said:
Please explian how this item (messes with ignition timing).

sam-missle
If you mess with the cam timing, you mess with the ignition timing too, in relation to the position of the piston in the bore relative to TDC. They are connected by gear mesh at the rear of the cam. Move the first (cam), you moved the second (distributor shaft) too. ;)
 
#7 ·
ericnova72 said:
If you mess with the cam timing, you mess with the ignition timing too, in relation to the position of the piston in the bore relative to TDC. They are connected by gear mesh at the rear of the cam. Move the first (cam), you moved the second (distributor shaft) too. ;)
Valve timing is valve timing, ignition timing is ignition. the dist. is driven off the cam gear only. you rotate the dist. around the driven shaft to set the ign. timing relative to TDC. Has nothing to do with valve timing. if that were the case millions of vehicles would have messed up ignitions, as most engines have timing chain or belt tensioners on them.

sam-missle
 
#8 ·
sam-missle said:
Valve timing is valve timing, ignition timing is ignition. the dist. is driven off the cam gear only. you rotate the dist. around the driven shaft to set the ign. timing relative to TDC. Has nothing to do with valve timing. if that were the case millions of vehicles would have messed up ignitions, as most engines have timing chain or belt tensioners on them.

sam-missle

millions of cars (old ones) do have misadjusted ignition timing.

When you phase the cam in and out with relation to TDC of the crank the ignition timing changes along with it as it is driven off of the back of the cam. If your cam timing changes under acceleration then if the distributor is driven off the back of the cam, it will change too.

This is also a reason for a lot of spark scatter on older worn SBC engines.
 
#9 ·
sam-missle said:
Valve timing is valve timing, ignition timing is ignition. the dist. is driven off the cam gear only. you rotate the dist. around the driven shaft to set the ign. timing relative to TDC. Has nothing to do with valve timing. if that were the case millions of vehicles would have messed up ignitions, as most engines have timing chain or belt tensioners on them.

sam-missle
We are discussing moving (variable) cam timing in a RUNNING SBC engine by way of a chain tensioning device. If the tensioner advances the cam, this will advance the ignition timing too because they are geared together. Unless you have an idea for a variable distributor housing positioner that will counteract the variable timing chain tensioner, the timing IS going to change.
 
#10 ·
ericnova72 said:
We are discussing moving (variable) cam timing in a RUNNING SBC engine by way of a chain tensioning device. If the tensioner advances the cam, this will advance the ignition timing too because they are geared together. Unless you have an idea for a variable distributor housing positioner that will counteract the variable timing chain tensioner, the timing IS going to change.

Because having two moving parts where there used to be none is always a good idea. :mwink:

The best thing I can think to use to get around it is just going with crank fired ignition.
 
#11 ·
That gizmo has been around for ages- and it never caught on.

If done "right", like the OM's do it, it can work very well.

Ford uses it on their cammer engines, Honda as well, IIRC. Prob. others. But done by an entirely different system hydraulics and ECM, etc.), although the basic principal is similar between them all.

Recently, Comp came out w/a variable timing deal for the Ford OHC that replaces the OEM unit that would (in stock configuration) advance the cam up to like 40 degrees, IIRC.

Problem was, with a healthy aftermarket grind, the valves would get too cozy w/ the pistons. The Comp mods brought this figure down considerably, but still allowed for a lot of degrees of movement. This has to be better than the previous option of eliminating the advance feature all together.
 
#12 ·
I would think that any difference in cam or ignition timing with this device is going to be very minimal,its a copy of this Comp Cams peice;
http://www.compcams.com/technical/Catalogs/106-07/320.pdf
The timing chain would have to have an awful lot of stretch in it before there would be an advantage to using this.And to call it a variable valve timing control device seems to be a bit of false advertising,its is a tensioning device,period.And 7-30 hp gain,this isnt even realistic !!! And the parts are affected by wear and need to be checked on a regular basis.Just another case of someone trying to lighten our wallets with an unecessary peice. JMO !!!
Guy
 
#13 ·
cam timing

Rhodes Hyd lifters did a similar thing. The lifters had a controlled bleed down so at lower rpm the lifters would bleed down giving less duration and lift and at higher rpm less bleed down time and closer to what the cam grind would do with solid lifters. I had a set years ago and they were noisy like solids at lower rpms.













r
 
#15 ·
There is no way on earth that taking any play out of a timing chain is going to result in a gain of 30 hp on a big block,a little common sense should tell you this.Again,this device does not control variable valve/cam timing,it puts tension on the timing chain,plain & simple.
Guy
 
#16 ·
Guy, I'm not trying to argue w/you :) , but unless I'm mistaken, this deal actually does change the cam timing- more than just taking up the stretch of an ordinary chain.

IIRC, the thing has a LOT of play, and the engine speed changes the amount of play, effectively (in theory, anyway) altering the timing.

Still very close to "snake oil", but not quite. At least the theory behind it is technically sound.
 
#17 ·
Actaulyl the tensioner does control variable valve timing, but I think it only adjusts it by like 6 degrees.


I did a very quick DD of a big block combo, kind of a hot street setup. at 7500 RPM it shows a 34hp difference just by advancing the cam 6 degrees, that cam retarded 6 degrees picks up 18 ftlbs at 3500 RPM- essentailly doing what it is designed to do. The problem is that the way it works is that when you stomp on it the cam is retarded, essentailly moving your power upstairs when you are probably looking for it at the midrange. Advancing a cam for cruise conditions would help slightly with milage but this system still has a LOT to work out- not something I would want to tackle.

It can shift cam timing while the enigne is operating though- a varaible cam timing system of sorts.
 

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#18 ·
You guys need to have a real close look at this product,there is absolutely no way that it has anything to do with any aspect of controlling variable cam/valve timing;
https://www.competitionproducts.com/prodinfo.asp?number=8271
Take a real close look,there are 2 little shoes that put a bit of tension on the timing chain,theres nothing else there !!! If you really think that this will affect cam timing by as much as 6 degrees,or make 30 + hp,you probably believe that the moon is made out of green cheese LOL

It can shift cam timing while the enigne is operating though- a varaible cam timing system of sorts

This item does not "shift cam timing while the engine is operating",as I say,take a real close look.There are no fancy little doodads that magiclly alter the cam timing here,look very,very close...
Guy
 
#22 ·
Well given the fact that it would most likely be used by a Saturday Night Racer as opposed to Joe Street, every little bit helps. If it got you 5HP that's 5 more than if not. As stated it's been around for some time but I never kinew anyone to use one. Probably if used with a Tornado it would be best. LOL
 
#23 ·
Deez said:
Well given the fact that it would most likely be used by a Saturday Night Racer as opposed to Joe Street, every little bit helps. If it got you 5HP that's 5 more than if not. As stated it's been around for some time but I never kinew anyone to use one. Probably if used with a Tornado it would be best. LOL
Only if that molecule-aligning magnet was hooked to the fuel line first! :rolleyes:

I've never spoken to anyone who has used one, either. Even google comes up pretty much empty.
 
#24 ·
All I have left to say on this subject is that you Yankees must be on crack cocaine.....
Us Canadians arent that dumb enough to belive crap like this.Anyone who thinks that a tiny bit of stretch in a timing chain is going to result in 30 + hp,one tooth off of timing,or 6 degrees of timing,obviously has zero experience with an engine dyno,or engine building.Think about where you are; This is a HOTRODDERS FORUM,not a worn out old engine place.Maybe you guys have never degreed a cam.If you had,you would not be posting thnking that a bit of slack taken out of a built small or big block,( or any other ),would make that much of a difference.
I've had my engine on a dyno,I speak from first hand experience.
Anyone here that thinks that a properly built engine will see any difference in hp levels by using a timing tensioner device is a complete idiot.And ap72,to think that there is any such thing as a 7500 rpm street build big block shows your ignorance in this discussion.
Again,all the OP posted on is a chain tensioning device,nothing else,look at what it is.
Guy
 
#26 · (Edited)
Theres two versions the pricey billit one and a average Joe one for $75.
I can see how it would alter the timeing , but I'm in the US. :rolleyes:
On the Comp unit the slacks on the other side, assuming there is enough slack would'nt it do the opposite of the cam correct , like retard on the lowend and advance up top? I think there is a patent on Cam Correct.
 
#27 ·
Guy Hiltz said:
All I have left to say on this subject is that you Yankees must be on crack cocaine.....
Us Canadians arent that dumb enough to belive crap like this.Anyone who thinks that a tiny bit of stretch in a timing chain is going to result in 30 + hp,one tooth off of timing,or 6 degrees of timing,obviously has zero experience with an engine dyno,or engine building.Think about where you are; This is a HOTRODDERS FORUM,not a worn out old engine place.Maybe you guys have never degreed a cam.If you had,you would not be posting thnking that a bit of slack taken out of a built small or big block,( or any other ),would make that much of a difference.
I've had my engine on a dyno,I speak from first hand experience.
Anyone here that thinks that a properly built engine will see any difference in hp levels by using a timing tensioner device is a complete idiot.And ap72,to think that there is any such thing as a 7500 rpm street build big block shows your ignorance in this discussion.
Again,all the OP posted on is a chain tensioning device,nothing else,look at what it is.
Guy

I'm not here to argue how much you do or do not understand, just to say taht the cam timing is altered with this system, yes it varies with the tensioners spring, and yes people do run 7500 RPM on big blocks on the street.

I tried explaining it as simpley as i could and I think most people understand the concept, to me its really not that complicated. A worn tensioner on many OHC engines pretty much produces the same effect, although it is not wanted in that situation.
 
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