Cam install question

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ValiantMike

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I'm currently breaking down my 318 to install Compcam XE268 with new chain and gears and a set of 302 heads. Car is 1964 Valiant 4spd with 3.91 rear. New timing gear for crank has notches for straight up, 4 degree advance, or 4 degree retard. Car is for 99% street use so should I just install it straight up, or not? Thanks Mike
 
Don't really have the answer to your question, but am very intersted in your results and how it turns out. My car is currently a /6 and perhaps I'm dreaming of swapping the 318 out of my parts dart, but been looking at the same cam and sounds like pretty much the same combo. If you would not mind letting us/me know how things go etc. (know not all engine builds and results will be identical, but still useful info overall)

If it were me, I'd contact Comp and give them the combination you are running including compression, headers or not, intake, carb etc. and see what they have to say. Know that is not a real answer to the question, but wishing you the best with the engine combo.

Cheers
 
Strictly street..i'd install it straight up...if you were racing it like i do i'd install it 4 degrees advanced,for more topend...
 
Interesting....if everything is normal with the cam and crank gears, I believe Comp has these cams already set to a fashion that is between 2 to 4 degrees advanced, I forget which one. They recommended that the cam be set "straight up". Thats how mine is. I have slighlty ported stock 318 heads with the XE268. It runs awesome and has a decent lope. Runs well on the street, even with my 2.76 gear and stock converter, although the gears are to be changed. i have the initial ignition timing set to 10* BTDC and total timing of 34*. Good luck with the setup.
 
340srule said:
Strictly street..i'd install it straight up...if you were racing it like i do i'd install it 4 degrees advanced,for more topend...
Click to expand...

You have it backwards, advancing a cam improves bottom end and retarding improves topend.


Chuck
 
Heres the specs on the cam. Mike

Brand: COMP Cams
Product Line: COMP Cams Xtreme Energy Camshafts
Part Type: Camshafts
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,600-5,800
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 230
Duration at 050 inch Lift: 224 int./230 exh.
Advertised Intake Duration: 268
Advertised Exhaust Duration: 280
Advertised Duration: 268 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.477 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.480 in.
Valve Lift with Factory Rocker Arm Ratio: 0.477 int./0.480 exh. lift
Lobe Separation (degrees): 110
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: No
Grind Number: CRS XE268H-10
 
Just got off the phone with Compcams and Moparj is correct, advance is built into the Extreme Energy cams already and they said to install it straight up. Once again, thanks to all for the help. Mike
 
Yes if you don't have the tools to degree it, put it in on the 0 dots.

Whatever you do, and I've seen this happen more that once, don't put the crank gear on the 4* advance and then line up the 0 dots. This equals smashed valvetrain components. Seen one guy do that TWICE on the same engine. After the first time I'd be looking as to why the valves are all bent.

Get some GM EOS or find some valvoline racing oil that has zinc in it. That will help with break in. DO NOT run straight engine oil designed for newer cars, it lacks the necessary zinc to protect the cam and lifters.

Good luck, it should run nicely when you are done.
 
Hey Mike, Roy here, If it were me, I'd get the reccomended centerline install number from Comp cams and get someone that has a degree wheel and dial indicator and Knows what there doing to make sure that the zero degree marks on your gears equal the rec. C-line by Comp cams. Good Luck!
 
As MoparJ mentioned Comp Cams builds 4 degrees of advance into their cams, so a 110 cam would be at 106 (set up at 0) and good for a street machine. I`d install it at 0 , it should give you good power across the rpm spectrum. Enjoy the ride!
 
SGBARRACUDA said:
Hey Mike, Roy here, If it were me, I'd get the reccomended centerline install number from Comp cams and get someone that has a degree wheel and dial indicator and Knows what there doing to make sure that the zero degree marks on your gears equal the rec. C-line by Comp cams. Good Luck!
Click to expand...

Roy has the best advice on this subject, better safe than sorry!
Bob
 
imo, comp cams is trustworthy enough that you can install it dot to dot and it will be right if you can't get a degree wheel.
 
If you think that you will put another cam into a motor, go out and buy a degree wheel and dial indicator. Even if you buy a cheap one from Harbor Freight it'll work ok. Then all you'll need is a flat piece of steel to make a piston stop to find tdc. I think that its one of the most important car tools that you can own.
 
More good advise. Actually I pulled the heads already so I can see piston tops. I think I'll check Harbor Freight and see if they have a degree wheel. I'll be sure to get some oil with zinc for breakin. Thanks for the tips. Mike
 
ValiantMike said:
I'm currently breaking down my 318 to install Compcam XE268 with new chain and gears and a set of 302 heads. Car is 1964 Valiant 4spd with 3.91 rear. New timing gear for crank has notches for straight up, 4 degree advance, or 4 degree retard. Car is for 99% street use so should I just install it straight up, or not? Thanks Mike
Click to expand...

Straight up worked good for me with that cam in my 340.
 
The LSA angle on the xe268 is 4 degrees less than the stock 340 cam 110 from 112. Comp recomends a 106 degree cl which is 4 degrees advanced.

Camshaft Specification Table
Part Number 20-223-3
Engine 1964-2000 Chrysler
273ci-360ci
8cyl.
Grind Number CRS XE268H-10
Description

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Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.477 0.48
Duration At 0.006 Tappet Lift 268 280

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Valve Timing At 0.006
Open Close
Intake 28 60
Exhaust 74 26

--------------------------------------------------------------------------------

These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 224 230
Lobe Lift 0.318 0.32
Lobe Separation 110

--------------------------------------------------------------------------------

Recommended Valve Springs 901-16
 
that is correct snewpy. but they are keyed for 4* advanced already so that straight up is 106 cl.
 
When I degreed mine I had to use mopar offset keys to get it to 106 cl. Not sure if machining off that much or what but it was not at 106 staight up. Just saying you should degree it to be sure its where you want it.
 
Snewpy, thanks for that info. I spoke to Compcam rep the other day and as soon as I told him that I was using an Extreme Energy cam, he said to install it straight up be cause it has a built in advance. I'm going to see if I can pick up a degree wheel tomorrow and doublecheck. I'll let you know how I make out. How did your engine run after your installation? Mike
 
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