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Re: Just returned from the track....Something is wrong!
[Re: 69L78Nova]
#254901
03/16/09 07:05 AM
03/16/09 07:05 AM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
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Quote:
I dont get where the vacuum leak would be coming from though. I have had two different intake manifolds on here. I forgot to add I am still running the stock stamped steel rocker arms. I figured Id throw that in as well
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Re: Just returned from the track....Something is wrong!!!
[Re: Crizila]
#254902
03/16/09 09:58 AM
03/16/09 09:58 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
You can cut the timing back 3-4 degrees, but it's not gonna help you out much. You need atleast a 3/8" fuel line - and thats out of the tank. To run in the low to mid 12"s, which is where you should be running, your fuel pump should be able to fill a one gallon can in about 30 seconds - minimum - and thats measured from where the fuel line connects to the carb. Forget what the pump MFG. tells you. You need to actually check it to be sure. Your 60 foot times are off about a tenth and 1/2 also, indicating you have a traction problem.
You don't need a 3/8 line, I've seen and driven 11 second cars w/ 5/16 line and a mechanical pump. Check your plugs and see if you are running lean. You might back the timing down a hair. What jets are your running? And drag radials aren't going to hook as well as real slicks I don't care what anybody says.
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Re: Just returned from the track....Something is wrong!!!
[Re: Mr.Yuck]
#254904
03/16/09 11:21 AM
03/16/09 11:21 AM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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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. His problems are much bigger than 3-4 degrees in ignition or cam timing. If he doesn't have a fuel delivery problem now, he definately will when/if he gets his "other problem(s)" sorted out. And speaking of fuel, we just got a lot more to feed this thread - "used cam". Gee, I wonder if that's when his problems started??? "140 psi cranking compression" - A tired 8:1 360 motor will deliver 20 PSI more than that - unless of course the cam timing is off, he only let it register one pump, cranking speed was 300 rpm, etc, etc, etc. " timing marks won't line up - off 1/2 tooth" - Pretty remote guess that the gears are miss-marked. R-U sure you are lining up the "0's" and not any other marks (advanced / retard marks) on the gears?? Here is a good tip: Go back to the last thing you changed that made the car have 3-5" of vacuum at idle and you will find your problem!
Fastest 300
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Re: Just returned from the track....Something is wrong!!!
[Re: Crizila]
#254905
03/16/09 12:09 PM
03/16/09 12:09 PM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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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. His problems are much bigger than 3-4 degrees in ignition or cam timing. If he doesn't have a fuel delivery problem now, he definately will when/if he gets his "other problem(s)" sorted out. And speaking of fuel, we just got a lot more to feed this thread - "used cam". Gee, I wonder if that's when his problems started??? "140 psi cranking compression" - A tired 8:1 360 motor will deliver 20 PSI more than that - unless of course the cam timing is off, he only let it register one pump, cranking speed was 300 rpm, etc, etc, etc. " timing marks won't line up - off 1/2 tooth" - Pretty remote guess that the gears are miss-marked. R-U sure you are lining up the "0's" and not any other marks (advanced / retard marks) on the gears?? Here is a good tip: Go back to the last thing you changed that made the car have 3-5" of vacuum at idle and you will find your problem!
Agree a low compression engine + a 509 cam = dog out of the gate.
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Re: Just returned from the track....Something is wrong!
[Re: 64Post]
#254908
03/16/09 07:49 PM
03/16/09 07:49 PM
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Joined: Jan 2003
Posts: 4,084
Indiana
W5Duster436
master
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master
Joined: Jan 2003
Posts: 4,084
Indiana
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Quote:
I'm running a 260/266 @ .050" cam and I've got 6 1/2" of vac.
As mentioned, I'd degree the cam first [ EDIT: set the timing] then check for vac leaks. 
Mine isn't much better but I pull 6" with a 275/275 @.050 solid and that's with initial timing at 20 BTDC. I have the same problem right now too in the fact that mine doesn't seem to want to pull much past 6800 and should hit 7k immediately. Hope you have good luck with it.
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Re: Just returned from the track....Something is wrong!
[Re: W5Duster436]
#254912
03/16/09 09:23 PM
03/16/09 09:23 PM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
Quote:
I'm running a 260/266 @ .050" cam and I've got 6 1/2" of vac.
As mentioned, I'd degree the cam first [ EDIT: set the timing] then check for vac leaks.
Mine isn't much better but I pull 6" with a 275/275 @.050 solid and that's with initial timing at 20 BTDC. I have the same problem right now too in the fact that mine doesn't seem to want to pull much past 6800 and should hit 7k immediately. Hope you have good luck with it.
You could have a fuel delivery problem. If you have enough head on it to use that cam, it shouldn't nose over.
I'm running 24* initial just to get off the transition circuit onto the idle circuit and I'm still running rich. It's a fairly new motor but I think I hit 6500 a few times last summer. Mine ought to spin up to 7K as well.
I had as much bad luck as a guy could have putting this one together. It fought us every step of the way. How 'bout it Lyle? I mean really, when was the last time you've seen a core shifted cam??
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Re: Just returned from the track....Something is wrong!
[Re: 64Post]
#254913
03/16/09 09:47 PM
03/16/09 09:47 PM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Plug the numbers into an online calculator and solve for theoretical static, cranking and dynamic compression; If you have them that is.
Last edited by 64Post; 03/16/09 09:47 PM.
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Re: Just returned from the track....Something is wrong!!!
[Re: 69L78Nova]
#254916
03/17/09 08:20 AM
03/17/09 08:20 AM
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Joined: Apr 2004
Posts: 1,396
Mass
dgc333
pro stock
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pro stock
Joined: Apr 2004
Posts: 1,396
Mass
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Quote:
Its not a low compression engine. Its 11.26 to 1. The compression test was done with 5 hits on the gauge, all plugs removed. From the day this motor was built, it never had any vacuum at idle, and always ran like a rat.
Not that its going to solve all of your problem but; How do you know your compression is 11.26:1?
I just did a quick calculation assuming flat top pistons at zero deck that have 5cc reliefs. A typical 0.039" thick compressed head gasket with a 4.150 bore and the edelbrock 65cc heads.
This claculates to 10.5:1. Did you cc the heads? they could be bigger and where are the pistons in relation to the deck? If the heads have bigger than advertised chambers or the pistons are below the deck you could very easily be down in the 9's on compression. To get the advertised compression of almost all pistons on the market for a 360 will require the deck of the block to be machined quite a bit.
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Re: Just returned from the track....Something is wrong!!!
[Re: dgc333]
#254918
03/17/09 11:10 AM
03/17/09 11:10 AM
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Joined: Dec 2003
Posts: 731
Aurora Colorado
BELVEDERE67
mopar addict
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mopar addict
Joined: Dec 2003
Posts: 731
Aurora Colorado
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Seems as tho that vacuum reading is where this issue is. But there are many reasons that it might be low. Since you changed the manifold, I'd go there. I agree that a 4 degree change in timing will not change much but the timing chain "line up" issue does need to be changed. You are going to have to open it up to check all these items. Pull the manifold and ck for leaks, check cam for wear (possible lobe going away). Redo the timing chain or get a new one and degreee cam. Put it back together and run again. Fuel line is ok but make sure that your fuel pump is up to par. These are difficult things to check but all must be done. There is not enough vacuum and you need to check why. The fact that the car got slower as the day went on does point to an issue. I should be running better and winding up better that it is. There is alot to check but if you want to solve the issue I don't really see another way. I helped 64Post with his issues and we are still chasing the problems. Just my
Last edited by BELVEDERE67; 03/17/09 11:16 AM.
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Re: Just returned from the track....Something is wrong!
[Re: BELVEDERE67]
#254919
03/17/09 12:01 PM
03/17/09 12:01 PM
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Joined: Jan 2003
Posts: 14,470
renton, Washington
ph23vo
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,470
renton, Washington
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also my car liked 28 degrees of initial timing that was with a 288-530 GK solid cam, stock oem longblock 68 barracuda had LD340, 750 DP, stock manifolds [original exh system still on car], stock aircleaner, street tires [F 70 14], stock converter, 4;56 gears, stock weight ran hi 12,s@ 108..13.2 103 with 3;23 gears... dan
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Re: Just returned from the track....Something is wrong!
[Re: Crizila]
#254920
03/17/09 12:28 PM
03/17/09 12:28 PM
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Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
Cranking ( dynamic) compression pressure is way too low for that cam. Should be in the 180psi range. Not likely your C.R.is 11.26:1. This would explain poor vacuum and soft bottom end while still having a decent speed - 106mph. The slugs are probably .015 - .020" down in the holes. BTW, most reputable cam Mfg's will give you a suggested dynamic compression pressure for a particular cam. It is much more important than the static number - but much less impressive
That's why I suggested getting all 3 compression numbers.
Cranking CR should fall within a certain range if all of the factors are known. If it's low, it suggests other problems -- one of them being incorrectly calc'd static CR. Worn rings and an incorrectly installed cam are some others.
Dynamic CR will always be lower than static CR as it's based on the intake valve closing point. It's conceivable that the OP has a DCR of 6.5:1. That's not going to get it at the track.
My point being that even if the OP re-starts the process back at the cam the end results could still be the same -- a general lack of compression. I'd like to see all numbers work out to a decent CR. His SCR has got be off by a good 1.0-1.5, IMO. Plus, if the intake valve is closing late to being off a tooth that compounds the problem. So there might be a combination of issues going on here.
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