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Camshaft installation; help please

Started by Mrbill426, May 28, 2021, 09:38:01 PM

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Mrbill426

I am trying to degree the new camshaft in our 340; it's pretty much a stock profile of 272/284 degrees with .444/.453 lift. 
The cam card from the manufacture calls for 110 degree intake centerline.  My timing chain set allows for installing the crank sprocket at zero, or 4 degrees advanced, or 4 degrees retarded.  When I install it at zero I end up with a 107 degrees center line; I have checked it several times since in the past I have just bolted the cam in and ran with.  I reinstalled the sprocket in the retarded position and sure enough it's at 112 degrees now.
 
I am wondering what would be better, leaving it alone at 107 degrees which I assume means 3 degrees advanced... or  going with the 112 degrees which is 2 degrees retarded??   Am I right to assume that the 107 centerline buy installing it straight up would give a tad bit more bottom end power??  Maybe I am splitting hairs over this pretty much stock rebuild.
I will be checking piston to valve clearances.

Thanks


Chryco Psycho

Most cams are installed 4* advanced from the CL on the intake lobe of the cam so install it @ 107* & you are 1 * retarded from where it should be at 106*. On the cam card it should hve an installed CL @ 106*

Mrbill426

#2
@Chryco Psycho thanks... here is the "card"; I don't see "106" on there at all  :huh:



Quote from: Chryco Psycho on May 28, 2021, 10:12:00 PM
Most cams are installed 4* advanced from the CL on the intake lobe of the cam so install it @ 107* & you are 1 * retarded from where it should be at 106*. On the cam card it should hve an installed CL @ 106*


Chryco Psycho

Who made this cam & why did you choose it ?
Factory cams have a 115* lobe separation , most lower RPM street cams have 112* , this one has 110* which is more high RPM but then why the low lift , for a stock type street cam you would do far better with a higher lift , lower duration & wider LSA like the 702 Lunati Voodoo grind IMO ..

Mrbill426

@Chryco Psycho it was made by a local cam grinder named Delta Camshaft that has been in business or decades and highly praised.  I asked them for an early ('68) Mopar 340 (4-speed) grind and relied on them to have the specs.  I only gave them what I knew to be the advertised lift and duration...this is what they built... perhaps it is wrong??  :huh:  It looks like the spec sheet is a print-out of how the cam tested out on their analyzer.   Stock exhaust manifolds will still be used, but I plan to swap out the cast iron intake for a LD340 and a carb that will fit it... factory air cleaner too.

Right now it is installed straight up and has a 107 degree intake centerline as a result.  I verified the lift at the valves with stock 1.5 ratio rockers will be .444"/.453".  I have installed +.020" forged pistons #L2316-20  that protrude slightly above the surface.  The stock cylinder heads measured at 70cc and after doing all the volume math I came up with a compression ratio of about 9.2:1.  Without the head gasket the intake clearance is .120" and exhaust is .111".

Appreciate your input very much  :bigthumb:




Quote from: Chryco Psycho on May 29, 2021, 07:55:45 PM
Who made this cam & why did you choose it ?
Factory cams have a 115* lobe separation , most lower RPM street cams have 112* , this one has 110* which is more high RPM but then why the low lift , for a stock type street cam you would do far better with a higher lift , lower duration & wider LSA like the 702 Lunati Voodoo grind IMO ..

rikkitik

#5
 If you intend to stay with this cam, I think you're fine at 107 ICL. Though the stated LSA is 110, your effective overlap (.050) is fairly short.
1 additional degree of advance, to a106 ICL, isn't going to be very noticeable on a basically warmed over stock rebuild. Depending on where your actual IVC number is, will also determine your "effective" compression ratio, and cranking pressure. A general "good number" for iron head maximum cranking pressure is about 175psi. It's possible to get away with higher, but your tuning skills need to be up to task. Advancing the cam will close the intake valve sooner, which will raise the effective compression ratio, and usually boost low end torque.
You have plenty of piston to valve clearance, so you should be fine there.
If you choose to go with a newer, faster ramp design, you will likely pick up some performance, but with your current choice you are pretty good where you are. (imho) 😉

Mrbill426

@rikkitik thanks for your thoughts too.  I am just trying to take this '72 "smogger" back it time a bit and make it more fun to drive without going crazy.   And not a racer so there will not be much high rpm high speed driving... I am going on 68 so that is behind me.  I do want it to respond at legal limits though.  I want to drive it distances so was concerned about too much compression on available pump gas.  It's automatic with a 3.23:1 sure grip axle.   I am about to button up the bottom end and would like to move forward but still don't want regrets either.  :(   Again I relied on the cam grinder who has been in business for decades and has great reviews to get it right.



Quote from: rikkitik on May 30, 2021, 11:15:36 AM
If you intend to stay with this cam, I think you're fine at 107 ICL. Though the stated LSA is 110, your effective overlap (.050) is fairly short.
1 additional degree of advance,  to 106 CL isn't going to be very noticeable on a basically warmed over stock rebuild. Depending on where your actual IVC number is will determine your "effective" compression ratio, and cranking pressure. A general "good number" for iron head maximum cranking pressure is about 175psi. It's possible to get away with higher, but your tuning skills need to be up to task. Advancing the cam will close the intake valve sooner, and raise the effective compression ratio.
You have plenty of piston to valve clearance, so you should be fine there.
If you choose to go with a newer, faster ramp design, you will likely pick up some performance, but with your current choice you are pretty good where you are. (imho) 😉


Chryco Psycho

Well I guess you can try the cam as is now & pull it later if you don't like it .
Or slide in a VooDoo 702 now & I know it performs very well .
Your call .

Mrbill426

@Chryco Psycho I get and understand that completely.  The question remains whether or not the cam they built is correct, meaning is it the right profile for a '68 340 or did they get it wrong??   :notsure: What say?
Thanks

Quote from: Chryco Psycho on May 30, 2021, 08:02:17 PM
Well I guess you can try the cam as is now & pull it later if you don't like it .
Or slide in a VooDoo 702 now & I know it performs very well .
Your call .

Chryco Psycho

It is incorrect for sure .
The factory cam has a 115* LSA yours has 110 , big difference , the 115* makes better vacuum thus 6 packs worked very well , change the cam & the carbs don't work as well with 110 or 112* LSA , not sure what carb you plan to run but Carters / Edelbrick are virtually impossible to alter the bleeds on to correct to response .

Mrbill426

@Chryco Psycho   Yeah wonderful  ::)  I truly expected them to know what they were doing... figured they would have some sort of master book that gave them all the info to build a US production factory cam.
I was going to use either a Edelbrock or a AVS as they should fit the LD340 while my TQ won't.   I am trying for the most stock appearing setup as I can manage.
I do NOT want to mess with changing cams, ever, so I will consider the 702.  I read where they "recommend" roller lifters though... not in my budget.  Does not look so radical to me that it would need them  :huh:  Good for stock exhaust manifolds thought.. that is in my ballpark.



Quote from: Chryco Psycho on May 30, 2021, 08:44:44 PM
It is incorrect for sure .
The factory cam has a 115* LSA yours has 110 , big difference , the 115* makes better vacuum thus 6 packs worked very well , change the cam & the carbs don't work as well with 110 or 112* LSA , not sure what carb you plan to run but Carters / Edelbrick are virtually impossible to alter the bleeds on to correct to response .


Chryco Psycho

The lift is about right but the duration , overlap & LSA are not . the later intake 71 up would fit the TQ , otherwise I would use an AVS Not the Edelbrock .
The Voodoo 702 is available in a hyd flat tappet , it is a great cam , works fantastic with exhaust manifolds , idles well & has good low end response & strong midrange power .

Mrbill426

@Chryco Psycho I have an AVS I held over that came off (originally) a '69 Roadrunner (383) I owned 4 decades ago, maybe I can resurrect it and give it a new life on a 340?  Seems low enough that I could use the original (Cuda) air cleaner as I wish to do.



Quote from: Chryco Psycho on May 30, 2021, 10:45:17 PM
the lift is about right but the duration , overlap & LSA are not . the later intake 71 up would fit the TQ , otherwise I would use an AVS Not the Edelbrock

FSHTAIL

Have you made contact to the manufacturer yet about it?

I'd be curious to see what they would say.   

I 2nd the Voodoo cam.       It was exactly as they stated when I had the degree wheel.      No doubt.   Right on the money. 
1973 BS23H Cuda' 340/TKX 5 speed (70 AAR clone-ish)

Mrbill426

I have not yet; i have just discovered this over the weekend.  I looked for that 702 camshaft and it is not list or not available.  That number is skipped in the sequence for small blocks, at least at Jegs, but is listed for big blocks.  Summit does not list any cams for a 340.  Unless my search is messed up.



Quote from: Chris D. on May 30, 2021, 11:28:50 PM
Have you made contact to the manufacturer yet about it?

I'd be curious to see what they would say.   

I 2nd the Voodoo cam.       It was exactly as they stated when I had the degree wheel.      No doubt.   Right on the money.