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Barber Dave's Avatar
 
Join Date: Nov 2001
Location: Wauseon Ohio
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Lightbulb Degreeing in engine, valves, timing

Ok , I remember back in my drag racing days , (1960's) the big thing was degreeing in Cam, setting valve lash with dial indecator,
and degreeing in the vibration damper to set timing accurately.
Has anyone done this to there 914 engine? I know its a lot of work
but were all a little anal retentive arn't we? I figure when your working with engines in the 80 hp to 95 hp (stock) even a couple of h/p might be worth it. At the least you would know your cam,timing, and valve lash is right on the money. I would bet Jake
and Otto do this to every engine that leaves there shop. What do you guys think, is it worth the time , and is there a few HP laying in wait some where there. Remember its winter here can"t drive ,got nothing but time. I would really be interested in Brad's and Dave D. opinion, but anyone jump in in . Thanks Dave
Old 12-08-2002, 02:50 AM
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Degreeing the cam is a process to make sure the valve events are occuring at the appropriate time. It is also a method of checking that a reground/custom grind camshaft was ground correctly.

If the cam is installed advanced or retarded, it will alter the running characteristics of the engine.

Remember, advancing or retarding the cam is a matter of about +/- 2 degrees in each direction. Anymore than this, valves and pistons may meet in an inappropriate manner.

Most of this is critical on a close tolerance engine (read as high compression, high lift cam, long duration, etc). My belief is that a stock cam with low lift and minimal duration does not need the process.

If I were building a "blueprinted" stock motor to achieve the absolute maximum factory horsepower design, I would degree the cam.

But you left out indexing the crank, equalizing deck height, ccing combustion chambers, equalizing valve height and more than a few other things.
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Old 12-08-2002, 07:38 AM
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The only adjustment you have on the Type IV's camshaft is moving the cam one complete gear tooth. I believe that winds up being too coarse an adjustment to do anything good....

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Old 12-08-2002, 11:26 AM
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The cam (Crower) and drive gear on my race engine have a set of eccentric washers that allow setting the cam timing to what ever you want. We had originally set cam timing to be right at 0 but after playing with the Dyno 2002 software we saw that if the cam was retarded 1 degree we gained about 15 ftlbs of touque and HP stayed the same! We had the engine apart in Sept to fix a broken valve and set the cam timing at 1 degree retarded and the accelaration out of corners especially at low speed feels better. One of these days we will have to put the car on adyno. Good luck.
Old 12-08-2002, 11:54 AM
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Dave,

John nailed it all. There used to be company around called (Dial-A-Cam) they sold adjustable came gears for the type4 that could be adjusted through the oil pump "hole". Its a PITA pulling the oil pump, but the cam gear worked correctly.

Your on the right track, but getting the proper pieces in place for you to adjust the cam could prove difficult. We check them and have the cam grinder make the changes for us (he is local and well known for racing camshafts)

B
Old 12-08-2002, 02:57 PM
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