Another dumb question----

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DesertRat

DesertRat

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Getting ready to install & degree my cam & check valve/piston clearance. The attached card shows my cam. I have a lower sprocket 4+, 0, 4-. Is the card telling me it wants to be installed with the 4 degree advance or just where 4 degees is in relation to the TDC of intake lobe?
What will the effect on DCR be in relation to cam advance with this setup? Just wondering where to set the cam advance, I am betting piston/valve clearance will not be an issue but will check on setup.
TIA-DR:coffee2:
 

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The cam company ground the cam 4 degrees advanced. Unless you plan on degreeing the cam with a degree wheel (definitely worth the time and effort to learn), install the crank sprocket on the 0 mark.
 
As above, ... it has 4 degrees advance ground in. The 112 LSA minus the 108 ICL = 4 degrees tells you that. The behavior of the engine is very responsive to cam timing changes so it is worthwhile IMO to get it right.

But, without degreeing, you won't know if it really installs there with a 0 degree sprocket setting. Our cam with 5 degrees of ground in cam advance degreed-in at about 3 degrees advanced with a 3 angle sprocket like yours set at 0, so we installed a Mr Gasket 2 degree offset crank key to get it to 5.
 
Thanks guys, I am definitely going to degree everything and have everything I need except offset keys. Kind of worried about obtaining those if I need them. Really want to get it right!
DR:prayer:
 
Mancini or Hughes may have some individual offset cam keys. I'd set up and check it first, you may luck out. On the engine I'm building now the keyway in the crank is off 3 1/2 degrees, even with multiple keyways on the crank and cam sprockets I still had to use my 1° offset key.
 
It may or may not have that 4* ground into it. That is proprietary information and usually cam companies will not divulge it. "Most" cam grinders do grind "some amount" of advance in, but not all and not 4* every single time. That's why it is imperative to degree the camshaft in.

With tolerances in machining from one camshaft and timing set to another, there's no guarantee that even if it is ground with 4* advance, putting it "dot to dot" will be in the right place.

Degree it. That's the only correct answer.
 
RustyRatRod said:
It may or may not have that 4* ground into it. That is proprietary information and usually cam companies will not divulge it. "Most" cam grinders do grind "some amount" of advance in, but not all and not 4* every single time. That's why it is imperative to degree the camshaft in.

With tolerances in machining from one camshaft and timing set to another, there's no guarantee that even if it is ground with 4* advance, putting it "dot to dot" will be in the right place.

Degree it. That's the only correct answer.
Click to expand...
Right, I will do that. My takeaway here is that cam will give best performance at it's design point of 4 degrees advance per the card? (I am particularly anxious to use my new 11" degree wheel and steel crank drive socket:)) I have the dial indicators and the rest of the items needed here.
 
Perhaps 'intended' performance is the right word. You can change the performance to some degree by advancing or retarding yourself. Advanced builds more cylinder pressure at lower RPM (per the DCR increase that you can calculate), and typically improves lower RPM performance, and retarding does the opposite. My impression is that the grinds of these mild to moderate cams have some advance built in so they will be better at lower RPM's and the customer's won't knock them for being doggy....
 
I heard one way to do a cam is to degree it until you get the highest cranking PSI ?
 
^^^ Never heard that one.... but, indeed it is ONE way.... LOL. Wouldn't it tend to lead to massive amounts of cam advance?
 
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