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Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #254981
03/18/09 08:46 PM 03/18/09 08:46 PM
Joined: Oct 2003
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Az
Crizila Offline
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Az
Shot - and a goal!!! Congrats azmopardart. U should be in the 12's before you know it. As to the valve train geometry issue: You are right moper - regarding the constant relationship between the pivit point ( center line of the shaft ) and the rocker to valve tip contact when the valve is closed - and this aint good when you install a cam with condiderable more lift than what the valve geometry was intended for. At full lift with a higher than stock lift cam, the point of contact starts to get real close to the edge of the valve stem, often doing some major side loading to the valve ( reads wears out guides and rockers ). The geometry change takes place on the push rod side. the distance between the lifter cup and rocker cup changes (remember I did say slightly ). This changes the push rod angle ( already crappy on small blocks ) between the two points and that in turn changes both the lift and duration of the cam. Changing the aformentioned relationship between the rocker tip and the valve stem to accomidate a higher lift cam can only be accomplished with a valve length change ( as moper stated ), shaft shims, or lash caps. Ok, now that the problem is solved, time to get busy on that 5/16" to 3/8" fuel line change----

Fastest 300
Re: Just returned from the track....Something is wrong! [Re: Crizila] #254982
03/18/09 08:53 PM 03/18/09 08:53 PM
Joined: Nov 2007
Posts: 21,819
Kirkland, Washington
Pacnorthcuda Offline
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...so had he degreed the cam in the first place....
Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #254983
03/18/09 08:55 PM 03/18/09 08:55 PM
Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices Offline
Why would you even post that?
HealthServices  Offline
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Joined: Dec 2007
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So Cal


Degreeing the cam will allow you to know exactly where the cam is. One problem down, (at least going in the right direction) hopefully it solved a couple other problems as well. And please do degree it even though you have good cranking compression.


Well done!

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.
Re: Just returned from the track....Something is wrong! [Re: Crizila] #254984
03/18/09 08:56 PM 03/18/09 08:56 PM
Joined: Oct 2003
Posts: 7,506
Az
Crizila Offline
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Crizila  Offline
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Az
EZ valve train geometry check: Remove the rockers. Wipe a few valve stems dry with solvent. Then color them black ( at least one intake and one exhaust ) with a magic marker. reinstall the rockers. Rotate the engine through several cycles. Remove the rockers and examine the contact pattern. If it's centered on the stem and not too near the stem edges, your good to go.

Fastest 300
Re: Just returned from the track....Something is wrong! [Re: Pacnorthcuda] #254985
03/18/09 08:57 PM 03/18/09 08:57 PM
Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices Offline
Why would you even post that?
HealthServices  Offline
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Posts: 7,759
So Cal
Quote:

...so had he degreed the cam in the first place....



And that's the problem with many of us we rather replace parts until it solves the problem.

Good thing he does not do this for a living!



Just think how much you would of been chasing this thing around if you did not bother to question cam timing!

Last edited by HealthServices; 03/18/09 09:17 PM.
Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.
Re: Just returned from the track....Something is wrong! [Re: Pacnorthcuda] #254986
03/18/09 09:11 PM 03/18/09 09:11 PM
Joined: Aug 2003
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Baltimore/Denver
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Quote:

...so had he degreed the cam in the first place....



...instead of lining up the dots...
Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #254987
03/18/09 09:22 PM 03/18/09 09:22 PM
Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices Offline
Why would you even post that?
HealthServices  Offline
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When finding TDC with the piston stop make sure to go VERY SLOW as you come up to the piston stop. You do not want to create any new problems.

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.
Re: Just returned from the track....Something is wrong! [Re: HealthServices] #254988
03/18/09 09:47 PM 03/18/09 09:47 PM
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:

When finding TDC with the piston stop make sure to go VERY SLOW as you come up to the piston stop. You do not want to create any new problems.



What... like breaking the stop off in the cylinder?
Re: Just returned from the track....Something is wrong! [Re: Crizila] #254989
03/18/09 10:02 PM 03/18/09 10:02 PM
Joined: Feb 2005
Posts: 143
North America
K
kwikblownhemi Offline
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Quote:

Interesting thread. Lotta experts here. I didn't say he didn't have a timing problem. I said cutting it back 3-4 degrees wasn't going to solve his problem. Neither is degreeing in his cam - if his marks are lined up correctly.



Lining the marks up means nothing. I had a customer's race 440 in the shop a few years ago because he couldn't get it to run - a real pig. I checked the cam timing and it was hugely retarded -about 15 degrees IIRC. Did I mention the marks were aligned? The cam gear/ a MP double roller set/ was marked off one tooth. Seems he hadn't wanted to go to the trouble to degree it when the engine was built.

It amazes me all the guys who drop big bucks on an engine build but won't spend less than $100 and an hour or so to degree the cam.

There's never enough money to do it right, but always enough to do it over.
Re: Just returned from the track....Something is wrong! [Re: kwikblownhemi] #254990
03/18/09 10:11 PM 03/18/09 10:11 PM
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Posts: 21,819
Kirkland, Washington
Pacnorthcuda Offline
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and some would be playing with fuel line at this point!

Re: Just returned from the track....Something is wrong! [Re: Pacnorthcuda] #254991
03/18/09 10:30 PM 03/18/09 10:30 PM
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:

and some would be playing with fuel line at this point!



I can't emphasize how funny I found that comment to be on a family forum, but it nearly involved a change of wardrobe. Perhaps... NPMPLMAO

Last edited by 64Post; 03/18/09 10:32 PM.
Re: Just returned from the track....Something is wrong! [Re: 64Post] #254992
03/18/09 10:42 PM 03/18/09 10:42 PM
Joined: Apr 2007
Posts: 2,327
Glendale, AZ
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69L78Nova Offline OP
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Well, I just tried degreeing the cam. Repeated it 6 times to verify my results. The number I came up with is 116.5. If this cam is on a 108*, then Im 8.5* out? Which direction do I go? Advance or retard? To my knowledge, I cant seem to find a source that had 8 degree offset keyways, or do you adjust for additional advance and retard via the crank sprocket as well? Any ideas? I verified TDC multiple times as well, just to be absolutely certain since this is my first time doing it
Re: Just returned from the track....Something is wrong! [Re: 64Post] #254993
03/18/09 10:45 PM 03/18/09 10:45 PM
Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices Offline
Why would you even post that?
HealthServices  Offline
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Joined: Dec 2007
Posts: 7,759
So Cal
Quote:

Quote:

When finding TDC with the piston stop make sure to go VERY SLOW as you come up to the piston stop. You do not want to create any new problems.



What... like breaking the stop off in the cylinder?



Yep been there done that!

Although I was not laughing when it happened 15 years ago.

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.
Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #254994
03/18/09 10:49 PM 03/18/09 10:49 PM
Joined: Nov 2007
Posts: 21,819
Kirkland, Washington
Pacnorthcuda Offline
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Quote:

Well, I just tried degreeing the cam. Repeated it 6 times to verify my results. The number I came up with is 116.5. If this cam is on a 108*, then Im 8.5* out? Which direction do I go? Advance or retard? To my knowledge, I cant seem to find a source that had 8 degree offset keyways. Any ideas?



Wow...thats off! Are you sure your TDC was accurate (which determines your positioning of the degree wheel)
If it is accurate, your WAYYYYY retarded, and need to advance. Summit makes a great billet 9 slot set for about $70 that would be great (+/- 2 degrees, +8 to -8) But I gotta question if your 116.5 is accurate.
Re: Just returned from the track....Something is wrong! [Re: Pacnorthcuda] #254995
03/18/09 10:50 PM 03/18/09 10:50 PM
Joined: Dec 2007
Posts: 7,759
So Cal
HealthServices Offline
Why would you even post that?
HealthServices  Offline
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Joined: Dec 2007
Posts: 7,759
So Cal





Double check your TDC.

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.
Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #254996
03/18/09 10:52 PM 03/18/09 10:52 PM
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post Offline
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Quote:

Well, I just tried degreeing the cam. Repeated it 6 times to verify my results. The number I came up with is 116.5. If this cam is on a 108*, then Im 8.5* out? Which direction do I go? Advance or retard? To my knowledge, I cant seem to find a source that had 8 degree offset keyways. Any ideas?



What does the cam card give for intake closing point ABDC, and what is your actual reading?

EDIT: We might have to look at how you're arriving at TDC.

Last edited by 64Post; 03/18/09 10:55 PM.
Re: Just returned from the track....Something is wrong! [Re: 64Post] #254997
03/18/09 10:58 PM 03/18/09 10:58 PM
Joined: Apr 2007
Posts: 2,327
Glendale, AZ
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69L78Nova Offline OP
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Its a MP cam. I didnt get a cam card with it
Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #254998
03/18/09 11:07 PM 03/18/09 11:07 PM
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Nevermind... that was no help.

How are you arriving at TDC?

Last edited by 64Post; 03/18/09 11:09 PM.
Re: Just returned from the track....Something is wrong! [Re: 64Post] #254999
03/18/09 11:13 PM 03/18/09 11:13 PM
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Posts: 2,327
Glendale, AZ
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69L78Nova Offline OP
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Using a degree wheel and an adjustable piston stop. I obtained the directions off of Comps website. Thats what I dont understand. I repeated each step multiple times to verify correct readings, and got the same numbers everytime

Re: Just returned from the track....Something is wrong! [Re: 69L78Nova] #255000
03/18/09 11:41 PM 03/18/09 11:41 PM
Joined: Aug 2003
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That's what I was going to suggest -- using an online instruction source so you could reference it step by step.

I'll look at Comp's site but in the mean time make sure you're reading the wheel correctly. If you're using the intake centerline method make sure you're using TDC and ATDC numbers -- not TDC and BTDC.

For example, if the lifter is .050" below max lift @ 80* ATDC and .050" below max lift again at 140 ATDC then the ICL is 110* (80+ 140/2= 110)
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