New camshaft install questions

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70Hardtop

70Hardtop

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HI, I'm building my first Mopar engine, a 340. I'm not sure about a couple of things, hope someone has more knowledge. First the specs: it is a CC (Comp cams), high lift hydraulic cam. Grind/Part # XE275HL -10. The Gross valve lift (both intake and Exh) is 0.525, Lobe Separation 110, Duration @ .06 and 0.050 = 275 /287 and 231 /237

First question is about what it says on the Specs card: It says "These specs are for the cam installed @ 106.0 degrees intake centre line"

But do I need to do anything special to make it 106 degrees? Or will it be automatically done at 106 if I just put it in with the cam sprocket timing mark lined up at TDC with the crank mark ? Or does it mean I have to buy a degree wheel and "dial it in"

SECOND question: I want to run light valve springs initially to avoid wiping a lobe on initial run-in as this is the most critical time for a cam. The valve springs recommended by CC for this cam are dual springs + a damper so they are pretty heavy. Is it ok to use worn original OEM springs (used 45 year ones from a 318) or do I need more pressure on the lobes to effectively run it in? Someone told me to pull the inner spring and damper out and run it with them initially, but I still think they might be too heavy to risk it.

Thanks
 
If you install that cam dot to dot, it should be at 106. However, you definately should get a degree wheel and degree it to be sure it is at 106. It aint hard to do, and it's good insurance.. I think you can use the old 318 springs if you want. or use just your new outers. A lot of people will tell you just to break it in with your existing setup.. I have done that myself in the past. But it is a little Risky...
 
You need to degree the cam and make sure that it's at 106 like they want it.

What that really means is Comp wants the intake lobe to be at full lift when the piston is 106 degrees past TDC.

You can line up the dots and hope it's right. Better to degree it. All you need is a degree wheel, dial indicator with magnetic base, a pointer and a pushrod cut off about 1 inch longer than deck height.

Then you did absolute TDC and go from there.

It's also a good time to check that the damper is marked correctly for TDC.
 
I wouldn't use 318 springs. They weren't designed for that kind of lift. You may hit coil bind and start breaking things. Use the springs Comp recommends and remove the inner spring.
 
the cam will have those same specs no matter where the intake centerline ends up. what can change is where valves open and close. If you just line up the dots, the intake centerline may end up advanced, or at 106*, or retarded-depends on how accurately things were machined-Chrysler and Comp stuff is fairly accurate. if the cam is advanced=more low end, less top end. retarded=less low end, more top end. break in with the comp outer spring and damper, without inner spring
 
yellow rose said:
You need to degree the cam and make sure that it's at 106 like they want it.

What that really means is Comp wants the intake lobe to be at full lift when the piston is 106 degrees past TDC.

You can line up the dots and hope it's right. Better to degree it. All you need is a degree wheel, dial indicator with magnetic base, a pointer and a pushrod cut off about 1 inch longer than deck height.

Then you did absolute TDC and go from there.

It's also a good time to check that the damper is marked correctly for TDC.
Click to expand...

Thanks for that good info, looks like I will have to buy a degree wheel, just to know in my own mind that it is ok. Good idea about checking the balancer also, hadn't thought about that. BTW, you have a spelling mistake in your 'permanent sentence of wisdom'. Should be "..TOO much is evident". not "to". Wrong word.
 
mopowers said:
I wouldn't use 318 springs. They weren't designed for that kind of lift. You may hit coil bind and start breaking things. Use the springs Comp recommends and remove the inner spring.
Click to expand...
Thanks Mopwers ! Good advice, hadn't thought that one through properly.
 
Marcohotrod said:
the cam will have those same specs no matter where the intake centerline ends up. what can change is where valves open and close. If you just line up the dots, the intake centerline may end up advanced, or at 106*, or retarded-depends on how accurately things were machined-Chrysler and Comp stuff is fairly accurate. if the cam is advanced=more low end, less top end. retarded=less low end, more top end. break in with the comp outer spring and damper, without inner spring
Click to expand...

Ok thanks Marco. But what if I check the cam installation with a degree wheel and it is actually out? The teeth on the sprockets are fairly course so not much room for fine adjustment. Do I complain to CC or throw in the bin or how does that get fixed?
 
70Hardtop said:
Ok thanks Marco. But what if I check the cam installation with a degree wheel and it is actually out? The teeth on the sprockets are fairly course so not much room for fine adjustment. Do I complain to CC or throw in the bin or how does that get fixed?
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Get yourself a fancy timing set
It will allow you to run the sprocket 2 degrees retarded, dead on, or 2 degrees advanced, depending on which keyway you use

That should give you what you need to time it right
 
70Hardtop said:
Thanks for that good info, looks like I will have to buy a degree wheel, just to know in my own mind that it is ok. Good idea about checking the balancer also, hadn't thought about that. BTW, you have a spelling mistake in your 'permanent sentence of wisdom'. Should be "..TOO much is evident". not "to". Wrong word.
Click to expand...


Good gawd, I never caught that one. I usually do. I'm blaming that on my iPad autocorrecting my stuff.
 
yellow rose said:
Good gawd, I never caught that one. I usually do. I'm blaming that on my iPad autocorrecting my stuff.
Click to expand...
hehe, yeah that would do it, I don't have an I phone myself but have seen their effects on emails from people when they make enquirys (inquirys?) about parts I have advertised.
 
diymirage said:
Get yourself a fancy timing set
It will allow you to run the sprocket 2 degrees retarded, dead on, or 2 degrees advanced, depending on which keyway you use

That should give you what you need to time it right
Click to expand...

Ok! Just looked through my parts and I actually do have one of those crank sprockets with the three keyways, and can see the +/- graduations on it. Now just have to get a degree wheel. Thanks
 
The three key timing set is hardly "fancy". You can get them with nine keyways, and adjustable camshaft sprokets as well. The three keyway sets are what I would consider entry level.
 
RustyRatRod said:
The three key timing set is hardly "fancy". You can get them with nine keyways, and adjustable camshaft sprokets as well. The three keyway sets are what I would consider entry level.
Click to expand...

oh, ok, I wasn't aware of that. Gosh, always learning...well I will see what the degree wheel says first then decide if I need one of those fancy ones. Thank you.
 
I looked at the spring pressures closed and open, and yeah, these have some fairly high pressures, higher than my personal limit for break in. But this all depends on the installed height, and the info for that is not in the original post.

Why not take an outer spring down to your local machine shop and ask if they can measure the rate, or, alternately, measure the spring pressures at both closed and fully open heights?

Are you using non-stock retainers and/or longer valves? I hope so because the stock installed spring height on stock type heads is 1.650" and .525" lift would yield an open spring height of 1.125" which is .050" SHORTER than the spring bind height of the 924-16 springs. These springs look to be made for a taller valve/retainer combination:
COMP Cams® - Valve Springs By Design

Or are you using the beehive springs? Need more info on heads, valves, retainers, etc.

BTW, BE SURE to use a moly paste type of cam lube for assembly!
 
70Hardtop said:
oh, ok, I wasn't aware of that. Gosh, always learning...well I will see what the degree wheel says first then decide if I need one of those fancy ones. Thank you.
Click to expand...

That's EXACTLY what I would do.
 
70Hardtop, I do not know if you still can get the offset jets from MoPar any more. They offer the keys in a package that range from a zero to 5* offset.

After you find out exactly where the cam is, you can use the offset keys to adjust the cam.

A 1* offset on the cam will not effect performance in a bad way. My cam went in off 3.5*. Now after adjustment, it is within .5*'s.
 
@4spdragtop had a post up a while ago with a link to degree wheels you could print off yourself
the links in that post are dead now, but he may have the file on his computer and might be able to resurrect t for you
(and save you 100 bucks over buying a tool you may only need once)
 
Thanks DM. I'll see if I can find it. If you google printable degree wheel I would imagine there are a few.
diymirage said:
@4spdragtop had a post up a while ago with a link to degree wheels you could print off yourself
the links in that post are dead now, but he may have the file on his computer and might be able to resurrect t for you
(and save you 100 bucks over buying a tool you may only need once)
Click to expand...
 
70Hardtop said:
hehe, yeah that would do it, I don't have an I phone myself but have seen their effects on emails from people when they make enquirys (inquirys?) about parts I have advertised.
Click to expand...
Don't you mean "inquiries"? :D
 
rumblefish360 said:
70Hardtop, I do not know if you still can get the offset jets from MoPar any more. They offer the keys in a package that range from a zero to 5* offset.

After you find out exactly where the cam is, you can use the offset keys to adjust the cam.

A 1* offset on the cam will not effect performance in a bad way. My cam went in off 3.5*. Now after adjustment, it is within .5*'s.
Click to expand...

That's interesting, I never heard of them before, only the multi-keyway sprockets. I will check out what I can find.
 
B3RE said:
Don't you mean "inquiries"? :D
Click to expand...
Yes I meant one of them, I always get them confused, one of them is a noun, the other is a verb, eg a Police Enquiry compared to when someone "inquires". Thanks !
 
nm9stheham said:
I looked at the spring pressures closed and open, and yeah, .......BTW, BE SURE to use a moly paste type of cam lube for assembly!
Click to expand...

Thanks for looking into that ns9TheHam. First the lube - yes I have plenty of good cam lube I can use, that part is the easy part ! Now, you mentioned 924-16 springs, but the recommended springs for this cam are the 995-16 springs, which I purchased with the cam. And even without the damper and inner spring, like you say, I feel they might be too heavy to run in the cam. I have other springs I can use, but I am glad that someone mentioned the bind heights etc, so the old factory 318 springs are definitely out. I am not using longer valves and not using beehive springs, and I am using Comp Cams retainers and locks. I will have to look up the installed height of the springs, but I think they were about 1.7". I think you can actually buy special break-in springs for cams - they are designed light and with plenty of tolerance for high lift cams to prevent bind. But for a one-off job, I would not buy them.
 
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