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302 engine issues.

  #1  
Old 09-01-2017, 07:47 PM
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302 engine issues.

So I got a 1976 f100 with a 302 engine. The intake was leaking fluids so I figured while I have the intake off I would upgrade from a 2 barrel to a Holley 4 barrel sitting on top of a Edelbrock performer intake. We marked the distributor base to block and cap to distributor. We put it all back together and got it running fairly descent. We decided to check the timing with the timing light and it was off the scale like 30+BTDC. This is when the fun began my neighbor thought we might of been off by one tooth from pulling the distributor because the rotor moved some. We pulled the distributor and adjusted it a little hoping the timing would be closer to the 8-14 BTDC but instead the truck ran like crap, missing and lost of power we were done for the day. That brings us to today we attempted to time the engine again, we found TDC and the rotor was pointing exactly to where the #1 plug was placed on the distr. cap, everything looked good. We fired the truck up and it was missing, throwing fire up the carb. and black smoke out the exhaust. Please help!
 
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Old 09-01-2017, 09:06 PM
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Are you disconnecting the vacuum advance and plugging the vacuum hose when you are checking the timing?
 
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Old 09-01-2017, 09:16 PM
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Originally Posted by jade79 View Post
Are you disconnecting the vacuum advance and plugging the vacuum hose when you are checking the timing?
Yes sir we are.
 
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Old 09-01-2017, 09:28 PM
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I'm thinking the newly rebuilt Holley 600 cfm 4 barrel carb. might be a big part of the problem.
 
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Old 09-01-2017, 09:31 PM
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Picture of my setup.
 
  #6  
Old 09-01-2017, 10:52 PM
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This was recently discussed; see my posting #21:

https://www.ford-trucks.com/forums/1...r-302-a-2.html

You probably had the correct relative timing the first time since the engine ran OK, but what you thought was cylinder 1 is something else, which is why when you put your timing light on it, it showed wild timing.

If you want to correct it, you should turn the engine by hand so the real cylinder 1 is at TDC (both valves closed, piston to the top.) Now re-stab the distributor so that the rotor points to around the 2 o'clock position. The terminal on the cap should have that "1" marking there, and plug the wire for C1 onto that terminal, and the rest in the proper order following it.
 
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Old 09-01-2017, 11:11 PM
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Thanks again xlt4wd90 for your continued interest and all your help in the past thread. I wanted to start a new thread about my 302 troubles instead of the thread about truck manuals. As I'm sure you read my situation went from bad to worse as we again tried to set the timing today. My neighbor is a good mechanic but this engine is stomping him. I think we had the timing set TDC today but the truck was still missing, also throwing black smoke out the exhaust(this is new) and flames out the top of the carb. Could it be the old rebuilt Holley carb. instead of timing?
 
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Old 09-01-2017, 11:15 PM
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The carb. is a Holley 600 cfm 4 barrel, and I read that for a stock 302 a 500 cfm carb. would be a better match?
 
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Old 09-02-2017, 01:29 AM
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A review of some basics (just in case!):

Ford V8 cylinder #1 is front-most on passenger side. Watch out for GM & Chrysler/Dodge mechanics!

Be absolutely positively no questions at all sure that cylinder #1 is at the top of the compression stroke. When you are sure that it is near the top of the compression stroke, you can probe through the #1 plug hole with a wire while moving crankshaft bolt with a breaker bar, to find the max piston upwards movement.

Then look at the damper. Does the timing mark on damper agree/pretty close? If not, it's possible that the damper's ring may have slipped with age. Rubber between the parts of the damper has been known to degrade over many years, particularly if it gets oil soaked over time.
 
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Old 09-02-2017, 09:55 AM
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Originally Posted by Torky2 View Post
A review of some basics (just in case!):

Ford V8 cylinder #1 is front-most on passenger side. Watch out for GM & Chrysler/Dodge mechanics!

Be absolutely positively no questions at all sure that cylinder #1 is at the top of the compression stroke. When you are sure that it is near the top of the compression stroke, you can probe through the #1 plug hole with a wire while moving crankshaft bolt with a breaker bar, to find the max piston upwards movement.

Then look at the damper. Does the timing mark on damper agree/pretty close? If not, it's possible that the damper's ring may have slipped with age. Rubber between the parts of the damper has been known to degrade over many years, particularly if it gets oil soaked over time.
Torky2, Thanks for your reply, and yes we are aware cylinder #1 is front passenger side. We have the Ford truck manual for engines as a guide. Everything was done exactly how you described it, we even had the valve cover off(I also have a valve tap, cylinder #2). When we turned the engine with a breaker bar we found TDC and the timing mark was pointing exactly at TDC and the rotor was pointing where we already had the #1 plug on the distr. cap. All plugs are positioned as they are supposed to be, 15426378. I have another friend coming over today to put another set of eyes on the problem.
 
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Old 09-02-2017, 03:39 PM
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My friend Bob came over today with his timing light and we went through everything again and the timing is set correctly at TDC. We than adjusted the distributor to 14BTDC and I'm thinking the timing is adjusted about as good as we can get it. So there is still the issue with the carb. spitting when the truck is revved up. I really think the Holley 600 cfm carb. is too much carb. for my stock truck. I will let my neighbor play around some more this Friday, maybe we can re jet it? The #1 spark plug is full of black soot so it is running rich. I'm happy for now to at least know the timing is right and only need to focus on the carb.
 
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Old 09-03-2017, 04:16 AM
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An annoying problem with Holley carburetors is the power valve rupturing when you have a backfire. Then it will leak fuel into the intake manifold at idle, and run pig rich. It's suppose to close with idle vacuum, and open with increasing load and reducing vacuum. A simple test is to see if the engine runs better as you open the throttle. The sure way is to open up the primary bowl and pull it out and check to see if the diaphragm is cracked.
 
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Old 09-03-2017, 08:40 AM
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Originally Posted by xlt4wd90 View Post
An annoying problem with Holley carburetors is the power valve rupturing when you have a backfire. Then it will leak fuel into the intake manifold at idle, and run pig rich. It's suppose to close with idle vacuum, and open with increasing load and reducing vacuum. A simple test is to see if the engine runs better as you open the throttle. The sure way is to open up the primary bowl and pull it out and check to see if the diaphragm is cracked.
Thanks xlt4wd90 I will be sure to give my neighbor that information when we work on the carb. Friday.
 
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Old 09-03-2017, 09:15 PM
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Is "Super tuning and modifying Holley carburetors" a good book to buy or is there a better book I should consider getting?
 
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Old 09-04-2017, 01:38 PM
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Originally Posted by BeauF0RD View Post
Is "Super tuning and modifying Holley carburetors" a good book to buy or is there a better book I should consider getting?
Well I went ahead and ordered this book and also a OTC 5613 vacuum gauge. I hope these two items will be helpful getting my carburetor tuned.
 

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