degreeing a cam

[vmrod]

I put an Edelbrock Cam in my car several years ago. While I have the timing cover removed on my engine, should I degree my cam?

 

[GerryLP]

I put an Edelbrock Cam in my car several years ago. While I have the timing cover removed on my engine, should I degree my cam?

If it is a relatively "stock" cam, then I would say that perhaps you don't need to (unless you're experiencing problems? ).

On a relatively "aggressive" cam, there is also a plethora of factors (i.e. engine specifications like compression ratio, cylinder head flow, etc) that should be considered in order to really take advantage of the cam profile.

To address both of these perspectives, one should start on the cam profile. If it is a relative "stock" profile, then chances are that the cam is opening and closing valves as advertised on the card. If it is an "aggressive" profile, then consider the engine specifications, and then ensure you tune the cam to take advantage of those engine specifications.

Either way, it sucks to do this while the engine is installed in the vehicle. IMHO...Not impossible to do, but it sucks. ad Try to determine if it is worth your time.

GerryLP:cool

 

[wishuwerehere82]

Gerry took the words out of my mouth.
Also, if you are running hydraulic lifters, it will be really hard to read the lift accurately and repeatably.

 

[vmrod]

Well, the front of the engine is down right now, the valve covers and spark plug wires are off too.

I've got Dart II iron heads with oversized valves, roller rockers, Edel. 750 carb., Edel.Perf.RPM manifold. The pistons are about the only stock item in the engine.

I'm not afraid to tear it down. Oh, the tranny is out right now too. (My new TCI Street Fighter came in yesterday, yay!)

 

[fine69]

I put an Edelbrock Cam in my car several years ago. While I have the timing cover removed on my engine, should I degree my cam?

Pardon my ignorance.... what exactly is degreeing a cam?

 

[GerryLP]

Pardon my ignorance.... what exactly is degreeing a cam?

Is the phasing or timing of the valve events in order to extract the best performance. This may sound like a text-book answer, but there aren't many ways to describe it.

In plain language, you're recording what the position of the piston is when a particular valve event occurs (i.e. was the piston just completing the compression stroke when the valve opened at a particular point).

And this is most logical when one compares a particular cam's advertised duration (i.e. a Compcam's Extreme Energy 268 cam) to the pistons stroke length. In a typical 350 engine, the stroke is 3.48" using 5.7 rods. A stroker engine may use a 3.50 stroke with 6.0" rod. So using the very same cam in the example above (the H268) will yield a different phasing or timing to what the pistons are doing in a particular stroke.

So as it can be seeing, one cannot just stick the same cam that made 330 Hp at the wheels for cousin Joe's 350 sbc in the stroker motor you're dreaming of putting together without first learning what the cam is doing at a particular stroke on your beloved stroker.

GerryLP:cool

 

[fine69]

Is the phasing or timing of the valve events in order to extract the best performance. This may sound like a text-book answer, but there aren't many ways to describe it.

In plain language, you're recording what the position of the piston is when a particular valve event occurs (i.e. was the piston just completing the compression stroke when the valve opened at a particular point).

And this is most logical when one compares a particular cam's advertised duration (i.e. a Compcam's Extreme Energy 268 cam) to the pistons stroke length. In a typical 350 engine, the stroke is 3.48" using 5.7 rods. A stroker engine may use a 3.50 stroke with 6.0" rod. So using the very same cam in the example above (the H268) will yield a different phasing or timing to what the pistons are doing in a particular stroke.

So as it can be seeing, one cannot just stick the same cam that made 330 Hp at the wheels for cousin Joe's 350 sbc in the stroker motor you're dreaming of putting together without first learning what the cam is doing at a particular stroke on your beloved stroker.

GerryLP:cool

Gerry,

Thanks for that xlnt description. I would think this is an important, if not prudent thing for one to do when they're outfitting their power plant - particularly with a 383.

Ralph

 

[grumpyvette]

after doing several comparisons between just installing a cam (DOT-to-DOT)

VS degreeing them in correctly, Im forced to point out that it depends to a HUGE extent on the CAM and how well it meets the specs.
while most cams Ive degreed in were well within about 2 degrees Ive seen some that were out of spec significantly (6 degs plus) if your useing a well known brand like CROWER,CRANE,LUNATI,ISKY etc. youll probably be fine, buy a bargin basement kit and your chances get better on problems, but youll still likely be ok. but degree it in correctly and you could easily gain(OR MORE CORRECTLY NOT CHEAT YOURSELF OUT OF, 5-10 hp) if the cams close to correct, if its well out side specs, youll never know it without degreeing it in and youll wonder whats wrong?
link to thread
keep in mind the cam may be within specs, and the roller chain gears or cam drive gears or the crank keyways ETC. may be out of speck also, thats one reason degreeing in the cam helps find problems

summit [color:"red"] $11 [/color] part # SUM-901064
ID ADVISE you spend the BIG BUCKS and get one before you screw up the crank or keyway

ways to turn over the engine WITHOUT the starter
theres large bolts for your ballancer

theres crank sockets

Crankshaft Socket Tool For turning AND MOUNTING Degree Wheels

CRANK NUTS

crank rotaters

flywheel turning tools

and your going to need at least one when you degree in a cam or do a compression or leakdown test

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3292&prmenbr=361
this kit comes with a video tape instructions and most of the tools needed
its not a bad deal
HERES instructions to read over
http://www.thedirtforum.com/degree.htm
http://www.hotrodder.com/kwkride/degree.html
http://www.454ss.com/whitess/Camshaft.htm
http://www.cranecams.com/?show=article&id=3
http://www.holley.com/HiOctn/TechServ/TechInfo/IECCTech8.html

http://www.moroso.com/catalog/categorydisplay.asp?catcode=27019

http://www.moroso.com/catalog/categorydisplay.asp?catcode=27015
moroso and TAVIA
http://www.tavia.com/cat0.html
carry most other tools youll need

 

[glen242]

Is the phasing or timing of the valve events in order to extract the best performance. This may sound like a text-book answer, but there aren't many ways to describe it.

In plain language, you're recording what the position of the piston is when a particular valve event occurs (i.e. was the piston just completing the compression stroke when the valve opened at a particular point).

And this is most logical when one compares a particular cam's advertised duration (i.e. a Compcam's Extreme Energy 268 cam) to the pistons stroke length. In a typical 350 engine, the stroke is 3.48" using 5.7 rods. A stroker engine may use a 3.50 stroke with 6.0" rod. So using the very same cam in the example above (the H268) will yield a different phasing or timing to what the pistons are doing in a particular stroke.

So as it can be seeing, one cannot just stick the same cam that made 330 Hp at the wheels for cousin Joe's 350 sbc in the stroker motor you're dreaming of putting together without first learning what the cam is doing at a particular stroke on your beloved stroker.

GerryLP:cool

A stroker engine WILL NOT use a 3.50 stroke (stock is 3.48) regardless of 6.0" rods. The rods do nothing to increase the stroke, it depends upon the crankshaft. A 3.75 crank with 5.7 or 6.0 rods will give you exactly the same displacement. A 383 stroker is an engine with a 3.75" stroke and a 4.030 bore.

 

[GerryLP]

A stroker engine WILL NOT use a 3.50 stroke (stock is 3.48) regardless of 6.0" rods. The rods do nothing to increase the stroke, it depends upon the crankshaft. A 3.75 crank with 5.7 or 6.0 rods will give you exactly the same displacement. A 383 stroker is an engine with a 3.75" stroke and a 4.030 bore.

There are many stroker combinations. I used a 3.50 as an example of increasing the stroke from 3.48 to 3.500 stroke. However, weld-filling the rod throw journals to increase stroke is an old technique that hot-rodders have used to stroke their 3.48 stroke crankshafts (as well as de-stroking).

Yes, I know that the 5.700 and 6.000 rods will only change the piston height if using the same stroke. :eyerole And by the way, one way to avoid the "decking" of the block (in order to change the compression ratio or quench) is to custom order the correct piston height in a set of pistons.

The example were used to illustrate how degreeing a cam CAN be important.

GerryLP:cool