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Author
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Topic: I need some tuning help
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 03-12-2001 05:48 PM
   
Ok I have got my engine running kinda....
info:
351w
stock 69 4v engine (new .030 bore with new cast pistons, rings, bearings ect...)
heads stock 69 351w new valve grind (no port work)
comp cams 270h cam
stock type lifters
valve springs as recommended by comp cams
stock rebuilt dist with pertronix module
1405 edelbrock carb. (sorry Alex its what I have and I cant buy a new holley right now)
I used a 67 289 bell housing flywheel and clutch and a 70 model toploader 4 speedrunning condition right now:
I disconnected the vacuum advance and set the timing to 6 degrees BTC and with the advance disconnected the engine seems to run OK (this is running it in the garage not driving) it seems to stutter a small amount when you rev the engine quickly. now after re connecting the advance the stutter gets much worse and seems to have a miss when the secondaries open. Where do I go from here?
is there something wrong with the advance?
maybe the jetting in the carb?(BTW I cleaned and kitted the carb and noticed that the jets are the same for the primaries and secondaries) any help would be greatly appreciated. Dennis Hearn
------------------
Disgruntled Autoworker
Toyota Motor Manufacturing
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Moneymaker
Administrator Posts: 27660
From: Lyons, IL, USA
Registered: May 99
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posted 03-12-2001 06:00 PM
It sounds like it's way too lean and hooking up the vaccum advance is only compounding the condition. I would richen it a a few sizes then set the timing about 14 or so degrees without the vaccum advance.  ------------------
Alex Denysenko Co-Administrator and Moderator NHRA/IHRA/SRA member
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 03-12-2001 07:04 PM
should I richen the primaries or secondaries or both and should both have the same size jets?
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Sandy
Journeyman Posts: 65
From: Costa Mesa, Ca. USA
Registered: Dec 1999
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posted 03-15-2001 09:28 AM
Well I would richen only the primaries to start as that is the only circuit you are using in the garage. The only way to see how its running with the secondaries open is to take it out and make a coupe of full throttle runs and then kill it right away and pull it over to the side of the road and take the plugs out and check them for color. Or take it to a dyno shop and have the exhaust gas analyzed under full power (more accurate than the method above)...but also more expensive. About $50 a pull on the dyno out here in the CA. I'm not so familiar with Carter's but to my way of thinking the secondaries should be larger than the primaries. Good luck.
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SteveLaRiviere
Administrator Posts: 46005
From: Saco, Maine
Registered: May 99
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posted 03-15-2001 09:32 AM
You should pick up an Edelbrock calibration kit for your carb. Here's the one you need, from our CarParts.com link:http://www.carparts.com/parts/newsearch3.asp?sourceid=2&itemid=8945&partsku=1479&autoidsearch=NO&reflink=0-619D08DBD37811D3A019006008055228-00210675702682370932-0-0 That is an easy car to tune. ------------------
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
'97 Probe GTS 2.5L Disposable Commuter
"Live Right! Keep your driveway all Ford!"
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 02-25-2002 04:53 PM
Hello everyone I havent been here for a while but I have been working on my car of late and I still have the same miss in my engine here are the things I have done since my last post:
New Holley 670cfm avenger carb.
changed the push rods to a set that are .060" shorter to check if the valves are too tight they were not.
new plugs
new plug wires
checked for vacuum leaks
checked the compression
all changes have had no effect
the engine does seem to run smooth at idle but at about 3000 rpm it misses
I had my wife hold the throttle steady @ 3000 and i got under the car and held my hand behind each header muffler and it is missing on both banks
I adjusted the timing from one extreme to the other and the miss never changed.
please help me guys I dont know a mechanic in my area that knows anything more than plugging in a computer........
oh yeah I also installed a msd 6al and a blaster 3 coil[This message has been edited by dhearn (edited 02-25-2002).]
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blown 351
Journeyman Posts: 68
From: Seattle, Wa. 98258
Registered: Dec 2001
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posted 02-25-2002 05:06 PM
Run the engine for a while at various RPMs,and also up at 3000 RPM where it misses, and remove all the spark plugs. Are they all the same color/shade ? What color is that? Examine the underside of the distributor cap with a powerful flashlight and a magnifying glass. Is there anything that looks like it could be a crack? Do the spark plug leads route close to each other from the cap to the plugs?
I know it's alot of questions, but if it were me, I would determine if I had an ignition problem or a fuel problem. Compression is good right?? What were the readings?
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 02-25-2002 05:16 PM
I cant remember the compression numbers but I do remember that all were pretty high and very close to the same. The last time I checked the plugs they looked a little rich but all were about the same.
I havent looked at the dist cap that closely yet but it was brand new.
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V8 Thumper
Gearhead Posts: 4681
From: Phoenix, Arizona
Registered: Dec 2001
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posted 02-25-2002 05:17 PM
quote:
Originally posted by blown 351:
Examine the underside of the distributor cap with a powerful flashlight and a magnifying glass. Is there anything that looks like it could be a crack? Do the spark plug leads route close to each other from the cap to the plugs?... I would determine if I had an ignition problem or a fuel problem
Yup, that's where I'd go with it. That Holley Avenger SHOULD take fuel out of the equasion as a possible problem, so I'd start looking for ignition problems
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Moneymaker
Administrator Posts: 27660
From: Lyons, IL, USA
Registered: May 99
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posted 02-25-2002 05:18 PM
Have you driven it yet or are all of these tests still in the garage? ------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
US Class Nationals link
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V8 Thumper
Gearhead Posts: 4681
From: Phoenix, Arizona
Registered: Dec 2001
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posted 02-25-2002 05:21 PM
A few more thoughts:New motor? Did you 'run in' the cam? How did you time the cam? Per Comp specs, or ??? [This message has been edited by V8 Thumper (edited 02-25-2002).]
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 02-25-2002 05:24 PM
Alex, I have driven it some it seems to have fair power but the four speed might be deceiving me also the fact that I drive a 4 cyl camry
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 02-25-2002 05:29 PM
I am kinda ashamed to say that I didnt degree my cam like I should have but i installed a cloyes true roller timing set and set it up according to the directions
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Moneymaker
Administrator Posts: 27660
From: Lyons, IL, USA
Registered: May 99
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posted 02-25-2002 05:32 PM
I would then pull #1 plug and see if you really have absolute TDC before I did anyting else. ------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
US Class Nationals link
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 02-27-2002 09:02 AM
Alex,
I enjoyed talking to you on the telephone and thanks for your advice although you did not keep this darn snow up your way cause it found its way to my house  As soon as the weather breaks I will try everything that you suggested and I will let you know what I find. I would also like to thank everyone else for their suggestions. I hope I find my problem soon.Dennis
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 03-05-2002 06:57 PM
OK,,,, here is what I found today.
I marked the harmonic balancer so that i could see aprox. 10 deg increments I then warmed the engine disconected the vacuum advance and set the timing to 6-8 degrees then I ran the engine up to about 3000 rpm (by ear) and the timing moved to about 25-30 degrees. I noticed a lot less miss or maybe none in this condition @ 3000 but when I eased the throttle up it started missing but at 3000 Ok. next I hooked up the vacuum advance reset the timing to 6-8 @ idle then increased RPM to 3000 and the timing jumped to about 50-60 degrees HHHEEELLLPPPP!!!!
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richard bohm
Gearhead Posts: 373
From: tucson,az-luray,va
Registered: May 2001
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posted 03-05-2002 10:02 PM
make sure you do not have the plug wires crossed. i realized that ford rewired tha 351w to reduce the load on the front main bearing and to reduce the crossfiring problem, but it can still rear it ugly head. also check the rotor. if it is cracked it can allow current to ground on the dist shaft. bad plugs wires and dist cap(even though they are new double check them anyway they may be defective) can also cause the problem. if your are still using points, make sure the dwell is set right and that the condensor is good. coil also can cause the problem. if these are good then replace the starter solenoid. if it is worn the disk inside can ground itself and cause the miss as it shorts the electrical system for an instant.
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RonnieT
Gearhead Posts: 895
From: Port Allen, La. 70767
Registered: Jun 99
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posted 03-05-2002 10:36 PM
Dennis, You do not say what type of distributor you have, points or electronic. You problem sounds just like on I had on my 69 351 when the breaker plate stop broke, timing would go sky high and the dwell would go off scale, the car would miss badly above about 2200 rpm's. This happened 2 times to me, always about 20 miles from home, and I could baby it home keeping the rpm's below about 2000. I fixed my problem with a MSD distributor and 6 Digital box. ------------------
Ronnie
69 mach1 351W-4V
70 Torino GT 351C-4v with a "shaker"
Mustangs and More Member #23
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 03-09-2002 07:04 AM
I ordered a new msd billet distibuter today I should recieve it and have it installed by next sat. I will post and let you all know if it helps
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dhearn
Gearhead Posts: 253
From: Georgetown, ky
Registered: Nov 2000
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posted 03-20-2002 06:29 PM
HAHAHAHAHAHAHAHAH I put in the new distributer today no miss hahahahahahah anybody want to buy a junk rebuilt ford distributer????????? well one minor setback in my haste I let one of my new wires lay on the header now I have 7 new plug wires Oh well at least no miss
Thanks for all the help especially alex who talked me through my dilema on the phone------------------
Disgruntled Autoworker
THE FEEL AND SOUND OF A FORD V-8 IS ALL THE DRUGS A MAN NEEDS
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RonnieT
Gearhead Posts: 895
From: Port Allen, La. 70767
Registered: Jun 99
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posted 03-20-2002 10:09 PM
Glad to hear the distributer fixed your problem. I know it took me awhike to finally dish out the cash for the MSD unit, but it sure made a difference in my cars performance. I had installed 3 rebuilt units over about a 15 month period, all developed the same problem.------------------
Ronnie
69 mach1 351W-4V
70 Torino GT 351C-4v with a "shaker"
Mustangs and More Member #23
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V8 Thumper
Gearhead Posts: 4681
From: Phoenix, Arizona
Registered: Dec 2001
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posted 03-20-2002 10:50 PM
 
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