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More Engine Problems #72898
06/13/08 10:45 AM
06/13/08 10:45 AM
Joined: Oct 2006
Posts: 842
Urbana, MD
B
bordin34 Offline OP
super stock
bordin34  Offline OP
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Joined: Oct 2006
Posts: 842
Urbana, MD
I know you guys are probably getting tired of my engine problems but here it goes. My last problem was a combination of being too lean and a bad coil. The engine is a 73 400 originally a 2bbl, now has a Holley 670 Street Avenger, 452 heads, mild cam, and headers.

Now I have the engine running and barely drivable. The car refuses to idle below 1000rpm and tries to die when put in gear unless I feather the throttle, but once it is in gear for a couple seconds I can let go of the gas and it will run all day.

I am no expert so I set the timing by getting the engine to a steady 3000rpm with the vac advance disconnected then moving the dist until I got what i thought was the highest rpm by ear. The car revs fine with now load all the way to 4500rpm, which is as high as I want to rev it. When I suddenly let off the throttle it backfires.

I tried power braking to see how it performs under load. I hold both pedals to the floor and the car refuses to go above 2000rpm and runs very rough. i can't even get a tire to spin.

I then tried road-testing it. From idle to 3500rpm it runs really rough and makes no power at all. In "D" under WOT it shifts out of first at 3500rpm. If I put it in "1" the car screams from 4000rpm-5000rpm. I think I have an ignition timing problem but am not sure.

Thanks,
Dan

Re: More Engine Problems [Re: bordin34] #72899
06/13/08 10:56 AM
06/13/08 10:56 AM
Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
cyphre666 Offline
cyphre666  Offline

Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
Way back when, I never used a timing light on light on my car. I would set the timing by ear.
Leave the vac. hooked up, turn your dist. until it just starts to put a load on it.
Sounds as if you are way to far advanced. I you go to far retarding the timing you will know it when you try to restart when hot. It will drag.



I am no expert so I set the timing by getting the engine to a steady 3000rpm with the vac advance disconnected then moving the dist until I got what i thought was the highest rpm by ear.

Re: More Engine Problems [Re: cyphre666] #72900
06/13/08 11:51 AM
06/13/08 11:51 AM
Joined: Jan 2003
Posts: 7,978
Bethel Ct
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AdamR Offline
master
AdamR  Offline
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Posts: 7,978
Bethel Ct
First thing to do is buy a timing tape for the balancer. Check initial timing and total timing.

Is this a Mopar Perf. distributor or a factory one ?

Re: More Engine Problems [Re: AdamR] #72901
06/13/08 11:58 AM
06/13/08 11:58 AM
Joined: Jan 2003
Posts: 74,911
U.S.S.A.
JohnRR Offline
I Win
JohnRR  Offline
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Posts: 74,911
U.S.S.A.
Quote:

First thing to do is buy a timing tape for the balancer. Check initial timing and total timing.

Is this a Mopar Perf. distributor or a factory one ?




no the first thing to do is buy a freakin timing light .

i can not believe how many people are timing their engines BY EAR ...


Re: More Engine Problems [Re: JohnRR] #72902
06/13/08 12:09 PM
06/13/08 12:09 PM
Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
cyphre666 Offline
cyphre666  Offline

Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
Timing by ear is Old School, and yes I have a timng light now.
Way back when, no timing light.
A lot of times timing numbers mean nothing, wear, cams, dist adv.all change your specs.
We could have the exact same specs on the same engines and one will react differently.
So, it is not all the nutty to time by ear.

Quote:

Quote:

First thing to do is buy a timing tape for the balancer. Check initial timing and total timing.

Is this a Mopar Perf. distributor or a factory one ?




no the first thing to do is buy a freakin timing light .

i can not believe how many people are timing their engines BY EAR ...





Re: More Engine Problems [Re: cyphre666] #72903
06/13/08 12:13 PM
06/13/08 12:13 PM
Joined: Oct 2006
Posts: 842
Urbana, MD
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bordin34 Offline OP
super stock
bordin34  Offline OP
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Joined: Oct 2006
Posts: 842
Urbana, MD
It is the stock dist.
I have a timing light but it is not an inductive one. I need to disconnect a plug wire to connect it so I didn't bother to use it.

Re: More Engine Problems [Re: bordin34] #72904
06/13/08 12:20 PM
06/13/08 12:20 PM
Joined: Jan 2003
Posts: 27,728
places
7
79powerwagon Offline
Too Many Posts
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Posts: 27,728
places
Again, I have to throw out here, can someone in the know, and in the area, help this guy out so he can learn the right way to do these things?

Re: More Engine Problems [Re: cyphre666] #72905
06/13/08 12:35 PM
06/13/08 12:35 PM
Joined: Jan 2003
Posts: 74,911
U.S.S.A.
JohnRR Offline
I Win
JohnRR  Offline
I Win

Joined: Jan 2003
Posts: 74,911
U.S.S.A.
Quote:

Timing by ear is Old School, and yes I have a timng light now.
Way back when, no timing light.
A lot of times timing numbers mean nothing, wear, cams, dist adv.all change your specs.
We could have the exact same specs on the same engines and one will react differently.
So, it is not all the nutty to time by ear.

Quote:

Quote:

First thing to do is buy a timing tape for the balancer. Check initial timing and total timing.

Is this a Mopar Perf. distributor or a factory one ?




no the first thing to do is buy a freakin timing light .

i can not believe how many people are timing their engines BY EAR ...









thats silly , are you going to make parts for your car with a file and and a hacksaw because modern motor driven equipment isn't OLD SCHOOL ???

he has a timing light , so what if it's not inductive pickup , now you are just being silly ...

Re: More Engine Problems [Re: JohnRR] #72906
06/13/08 12:39 PM
06/13/08 12:39 PM
Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
cyphre666 Offline
cyphre666  Offline

Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
So, you are saying you can build duplicate engines with all the same parts and they will all perform exactly the same,
Not in a Million years

Re: More Engine Problems [Re: cyphre666] #72907
06/13/08 12:44 PM
06/13/08 12:44 PM
Joined: Apr 2007
Posts: 1,261
ILL
mark7171 Offline
pro stock
mark7171  Offline
pro stock

Joined: Apr 2007
Posts: 1,261
ILL
Quote:

So, you are saying you can build duplicate engines with all the same parts and they will all perform exactly the same,
Not in a Million years




i missed the first part. but in class that is exactly what we did. used the same parts dynoed them at got the same results(within reason)..hmmmmm

Re: More Engine Problems [Re: bordin34] #72908
06/13/08 12:54 PM
06/13/08 12:54 PM
Joined: Oct 2003
Posts: 3,999
South Park, Pa.
68LAR Offline
master
68LAR  Offline
master

Joined: Oct 2003
Posts: 3,999
South Park, Pa.
Quote:

I know you guys are probably getting tired of my engine problems but here it goes. My last problem was a combination of being too lean and a bad coil. The engine is a 73 400 originally a 2bbl, now has a Holley 670 Street Avenger, 452 heads, mild cam, and headers.

Now I have the engine running and barely drivable. The car refuses to idle below 1000rpm and tries to die when put in gear unless I feather the throttle, but once it is in gear for a couple seconds I can let go of the gas and it will run all day.

I am no expert so I set the timing by getting the engine to a steady 3000rpm with the vac advance disconnected then moving the dist until I got what i thought was the highest rpm by ear. The car revs fine with now load all the way to 4500rpm, which is as high as I want to rev it. When I suddenly let off the throttle it backfires.

I tried power braking to see how it performs under load. I hold both pedals to the floor and the car refuses to go above 2000rpm and runs very rough. i can't even get a tire to spin.

I then tried road-testing it. From idle to 3500rpm it runs really rough and makes no power at all. In "D" under WOT it shifts out of first at 3500rpm. If I put it in "1" the car screams from 4000rpm-5000rpm. I think I have an ignition timing problem but am not sure.

Thanks,
Dan




Just from reading this, I might suggest 2 things to get you going. First, check the wires to the coil. It sounds like they are reversed. The wire from the distributor goes to the negative side of the coil. Second, buy a timing light if you don't want to use the one you have.
Good luck,
Larry


4 speed street legal. Best time 10.99 @ 124 mph on 93 octane pump gas @ 3926# total weight
Re: More Engine Problems [Re: 68LAR] #72909
06/13/08 01:07 PM
06/13/08 01:07 PM
Joined: Oct 2004
Posts: 2,799
Connecticut
FurryStump Offline
master
FurryStump  Offline
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Joined: Oct 2004
Posts: 2,799
Connecticut
Start from the begining, Check your coil connections,check the plug wires are in the right order and fully connected,wires don't have any burns spots in them. You have to elimnate some of the variables from the situation. Guessing will get you frustrated and usually doesn't work. Don't assume anything. Start from the plugs back. Any plugs fouled, insulators cracked,what's the cap and rotor look like. Set the timing accurately. To me that means a light. You MUST go through it in a methodical way.


best of 11.39 at 117 mph 1.60 60’. 68 340 S Barracuda Fastback F.A.S.T [IMG]http://i67.tinypic.com/2mnnnnt.jpg[/IMG]
Re: More Engine Problems [Re: mark7171] #72910
06/13/08 01:10 PM
06/13/08 01:10 PM
Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
cyphre666 Offline
cyphre666  Offline

Joined: Dec 2005
Posts: 1,233
Eastern North Carolina
Sounds like you have a job waiting for you.
Top Fuel, Funny car, Prostock, Nascar.
Good luck and will I will await to see you on the winning teams.
I know it has gotten off the man's problem.
So, I will not post on this subject anymore


Quote:

Quote:

So, you are saying you can build duplicate engines with all the same parts and they will all perform exactly the same,
Not in a Million years




i missed the first part. but in class that is exactly what we did. used the same parts dynoed them at got the same results(within reason)..hmmmmm



Re: More Engine Problems [Re: cyphre666] #72911
06/13/08 02:03 PM
06/13/08 02:03 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
Too Many Posts
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Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
There is no good reason for the average person to set timing by ear. It may work, but why not have the peace of mind that your timing is set correct? Going by ear, you don't even know beyond a reasonable doubt that you're in the ball park. Even dial back timing lights are cheap enough on that auction site.

Secondly, after you've got the timing confirmed, check to make sure your plug wires are routed correctly. Supposedly there's two wires on BB mopars that are easy to mix up but will still run. Never happened to me, but I thought I'd throw it out there. How new are your plugs/wires/rotor/cap?

Next after you're sure it's not an ignition timing problem, try manually disconnecting the secondaries on the carb. If it still runs poor to 3500rpm, then I suspect you can have a jetting problem there.

Another thing, you say you have a mild cam in there, what's the specs on it? I have to ask because a 73 400 will have low CR pistons in it. Also, was the cam degreed at all during installation or did you just line up the dots?

Re: More Engine Problems [Re: DaytonaTurbo] #72912
06/13/08 02:29 PM
06/13/08 02:29 PM
Joined: Jan 2003
Posts: 27,728
places
7
79powerwagon Offline
Too Many Posts
79powerwagon  Offline
Too Many Posts
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Joined: Jan 2003
Posts: 27,728
places
He's been posting for a month or two now about basically the same thing. He is young, broke, and inexperienced with these cars.

He isn't following the information provided due to a number of reasons that we cannot pin down (doesn't understand what we are saying?, won't get help?, lazy?, perhaps dyslexic?, not enough time to invest in the project?, whatever the reason is).

Somebody needs to spend a couple of hours with him and SHOW him the proper way to tune an engine. He'll do it once, from start to finish, and he'll remember it forever!

I can't do it, but who is close enough that they can?

Re: More Engine Problems [Re: 79powerwagon] #72913
06/13/08 03:33 PM
06/13/08 03:33 PM
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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moper Offline
I Live Here
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
bordin, If you are indeed young and inexperienced, that's not a big deal. Just add "and open to suggestions". You can set the timing by ear all day long, it means nothing, as was said. It does sound like you may have more than a simple timing issue, but that's an easy one to fix. The factory distributor will continue to advance way beyond 3000 rpm. In fact, it's barely coming in at that point. So ear timing is a load of BS. BEsides, the engine's not under any laod. How can you think that's the same as full throttle? That's like setting tire pressure by eye. Sure, you know it's got enough, but too much looks the same as just enough. If you have non performance parts in terms of ignition, then dont try using performance settings for specs. I suggest until you can learn, adn invest ina timing light, you pay a place to set the timing and carb for you. It will be less money that the fuel and misc crud you will start buying trying to fix a non issue.


Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
Re: More Engine Problems [Re: bordin34] #72914
06/13/08 04:14 PM
06/13/08 04:14 PM
Joined: Oct 2004
Posts: 8,165
Left Coast
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BobR Offline
master
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Joined: Oct 2004
Posts: 8,165
Left Coast
"I am no expert so I set the timing by getting the engine to a steady 3000rpm with the vac advance disconnected then moving the dist until I got what i thought was the highest rpm by ear."


You are probably at about 60 degrees BTDC timing this way. Max RPM has nothing to do with timing your motor. Unless you use a light you are wasting every body's time. I agree with Powerwagon that somebody else should be doing this. -Bob

Re: More Engine Problems [Re: BobR] #72915
06/13/08 04:31 PM
06/13/08 04:31 PM
Joined: Jan 2003
Posts: 16,376
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dogdays Offline
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with BobR and others, your timing is way advanced. You want, on a bigblock, 38 degrees of mechanical timing in by 3000 rpm.

To those of you who persist in thinking every engine is different, you're wrong. I would have said the same thing about 10 years ago, but after studying countless engine buildups I have come to the firm belief that every combustion chamber has its own ignition timing characteristics. The mostly quiescent open chamber bigblock Mopar heads nearly always make max power with 38 degrees mechanical timing, add vacuum to get mileage at part throttle. Smallblock Mopar open chambers like 35-36 degrees, get some squish going and you can go down nearer to 30 degrees. Chevy Vortec heads, their 062 or 906 heads, make best power at 32 degrees.

If you twisted the timing for maximum engine speed you probably set the timing where it would be with mechanical and vacuum advance and it would be around 55 degrees. That's WAY too much ignition lead.

So, first get a decent timing light. A good inductive light is about $30. Then get the MP timing tape, costs like $6. Set mechanical timing at engine speed of 3000 rpm to 38 degrees BTDC with the vacuum advance disconnected and plugged. Then reconnect the vacuum advance and drive the car. It will run as it is supposed to.

R.

Re: More Engine Problems [Re: dogdays] #72916
06/13/08 04:34 PM
06/13/08 04:34 PM
Joined: Jan 2003
Posts: 27,728
places
7
79powerwagon Offline
Too Many Posts
79powerwagon  Offline
Too Many Posts
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Posts: 27,728
places
If you're going to use the timing tape, be sure to set a real, mechanical TDC, as your damper may have moved or otherwise not be quite correct.

Re: More Engine Problems [Re: 79powerwagon] #72917
06/13/08 04:43 PM
06/13/08 04:43 PM
Joined: Jan 2006
Posts: 349
Athens,Ga
M
mjk5thave Offline
enthusiast
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Joined: Jan 2006
Posts: 349
Athens,Ga
just wondering what type of rockers your using. My grand parents had a 72 new yorker with a 400 in it one time that ran like crap bearly moved. come to find out my uncle put the rockers on back words rights where on the left and so forth. Just a thought.


Mark

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