429 help, please!
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Junior User
Joined: Apr 2008
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429 help, please!
Hi Fella's,
this is my first post here, and I (or my truck) needs some help!
I've got a 1966 F 100, with a slightly built 1970 429.
Complete engine rebuid, with stock heads.
Ok, so I wanted to add a little "show" and more horse power,
so I tossed on a new set of Edlebrock aluminum heads,
rocker rolls, and new shorter push rods.
Same carb, same intake.
I fired it up and it runs real rough at idle, it doesn't seem to have the power it did before, and now, I have gas in the brake booster hose!
I went through the carb today and put in a new power valve (to specs), and new gaskets.
Still that same thing!
I am lost, frustrated, and ready to put the old stuff back on, and call it a day.
Any suggestions, or ideas will be greatly appreciated.
Thanks in advance.
this is my first post here, and I (or my truck) needs some help!
I've got a 1966 F 100, with a slightly built 1970 429.
Complete engine rebuid, with stock heads.
Ok, so I wanted to add a little "show" and more horse power,
so I tossed on a new set of Edlebrock aluminum heads,
rocker rolls, and new shorter push rods.
Same carb, same intake.
I fired it up and it runs real rough at idle, it doesn't seem to have the power it did before, and now, I have gas in the brake booster hose!
I went through the carb today and put in a new power valve (to specs), and new gaskets.
Still that same thing!
I am lost, frustrated, and ready to put the old stuff back on, and call it a day.
Any suggestions, or ideas will be greatly appreciated.
Thanks in advance.
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Junior User
Joined: Apr 2008
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I checked/set the floats and they are fine.
This is the first time I had to adjust valves. Every other BB Ford engine I've built had the stock heads with the non-adjustable rockers.
Tork 'em to 45 pounds and go!
That said, I've been through the valves 3 different time to be sure they are correct.
Maybe I need to do it a fourth time?
This is the first time I had to adjust valves. Every other BB Ford engine I've built had the stock heads with the non-adjustable rockers.
Tork 'em to 45 pounds and go!
That said, I've been through the valves 3 different time to be sure they are correct.
Maybe I need to do it a fourth time?
Postmaster
Joined: Nov 2001
Posts: 3,351
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From: Escondido, CA
I would be inclined to say it is going to be a vacuum leak. I'm assuming your running a stock intake manifold since a name for it and the carb haven't been dropped. When you mentioned the power valve in your first post I'm inclined to say you have a Holley carb though.
So why did you install short push rods? Was it something Edelbrock wrote in the installation instructions? Did you actually check the push rod length with the proper tools to verify the suggested push rod? The engine could be running like crap from the valves barely opening. Not to mention too long or short of a push rod will tear up valve guides ubber fast.
To check for a vacuum leak attach a vacuum gauge to your intake manifold and see what it is doing. There is a guide that comes with your gauge when you buy one that explains all the different reading meanings. It will even tell you if your valves are not set correctly unless you have a radical cam with overlap when the intake and exhaust valves are open.
Another thought just occured to me that you might have the distributor vacuum advance hooked up to the wrong port on the carb.
So why did you install short push rods? Was it something Edelbrock wrote in the installation instructions? Did you actually check the push rod length with the proper tools to verify the suggested push rod? The engine could be running like crap from the valves barely opening. Not to mention too long or short of a push rod will tear up valve guides ubber fast.
To check for a vacuum leak attach a vacuum gauge to your intake manifold and see what it is doing. There is a guide that comes with your gauge when you buy one that explains all the different reading meanings. It will even tell you if your valves are not set correctly unless you have a radical cam with overlap when the intake and exhaust valves are open.
Another thought just occured to me that you might have the distributor vacuum advance hooked up to the wrong port on the carb.
Last edited by airharley; Apr 8, 2008 at 09:05 AM. Reason: missing info
Thread Starter
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Junior User
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I would be inclined to say it is going to be a vacuum leak. I'm assuming your running a stock intake manifold since a name for it and the carb haven't been dropped. When you mentioned the power valve in your first post I'm inclined to say you have a Holley carb though.
To check for a vacuum leak attach a vacuum gauge to your intake manifold and see what it is doing. There is a guide that comes with your gauge when you buy one that explains all the different reading meanings. It will even tell you if your valves are not set correctly unless you have a radical cam with overlap when the intake and exhaust valves are open.
Another thought just occured to me that you might have the distributor vacuum advance hooked up to the wrong port on the carb.
To check for a vacuum leak attach a vacuum gauge to your intake manifold and see what it is doing. There is a guide that comes with your gauge when you buy one that explains all the different reading meanings. It will even tell you if your valves are not set correctly unless you have a radical cam with overlap when the intake and exhaust valves are open.
Another thought just occured to me that you might have the distributor vacuum advance hooked up to the wrong port on the carb.
I hooked up a vaccum gage and it reads out at 12 inches.
The truck ran fine with the old heads, and that is all I changed out (including the roller rockers and the new push rods).
I changed the push rods because the stock rods were to long, and the geometry was off.
That said, I wanted more HP, so that is why I changed the heads.
I know......if it ain't broke!!
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Junior User
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I pre-set the valves before I started it (and I did that three time just to be sure), as per the guys at Fast Times, here in Chicago.
There is no ticking at all, and I'm running a mild hydraulic cam.
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Elder User
Joined: Jul 1999
Posts: 877
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From: Missouri
The vacume leak may be in the brake booster. Pinch the hose off and see if it smooths out. I've had it happen on two different trucks.
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Elder User
Joined: Nov 2003
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From: southeast Idaho
I do not know what the instructions said on valve adjustment, but if you went anything over 1/4 turn from zero lash its probably too tight and possible your valves are not closing all the way, some anyway and recheck the firing order of the wires, thats real easy to get out of synch, took me several tries to get the different cylinder number location to jive with what I was doing, its just backwards to me is all.. Other than that, recheck the pushrod length with a checking tool.. Hope I said something useful!
Senior User
Joined: Mar 2008
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not sure about p.rod length for the edelbrock heads, most 460 use the 8.550 to 8.650
sounds like ya got the valves right, hydraulic cams are pretty easy
(tighten to slight finger resistance while the cam is on the base circle and then 1/2 turn)
id try to cap off some of the vacume ports 1 by 1 and see what happens
--is it possible you have a intake or carb leak, or timin slightly off
sounds like ya got the valves right, hydraulic cams are pretty easy
(tighten to slight finger resistance while the cam is on the base circle and then 1/2 turn)
id try to cap off some of the vacume ports 1 by 1 and see what happens
--is it possible you have a intake or carb leak, or timin slightly off
Thread Starter
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Junior User
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I do not know what the instructions said on valve adjustment, but if you went anything over 1/4 turn from zero lash its probably too tight and possible your valves are not closing all the way, some anyway and recheck the firing order of the wires, thats real easy to get out of synch, took me several tries to get the different cylinder number location to jive with what I was doing, its just backwards to me is all.. Other than that, recheck the pushrod length with a checking tool.. Hope I said something useful!
(tighten to slight finger resistance while the cam is on the base circle and then 1/2 turn, then tighten the lock down nut (i forget the proper term fo it))
With the stock push rods, the geometry was off and the rocker was sitting towards the back of the valve stem, hence a slighty shorter rod, which is now centered on the stem.
Firing order is correct, as is the placement of the distributor.
The timing is a little goofy. With the stock heads, I could set it to book spec, or a little advanced. With the new heads, I'm way more advanced, and I messed with the timming a lot, because I thought that was the initial problem.
I went this morning and checked the compression on it and they all read out between 155, and 170 pounds. The plugs are dry and not soaked with gas.
Then started it, I let it warm up, and then I sprayed ether all along the intake, front back and sides, and also along the carb base, and vacuum plugs.
Basically, any and every where I could think of where a leak might occur, and nothing!
The only thing left to do is to re-set the valves, and/or get a different carb.
After that, I'm TOTALLY lost!!
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Junior User
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Thanks to all for the suggestions, and I will let you all know the out-come,
and or what I find is the problem..
(maybe I should put a small block chevy in it?)
LOLOLOL.................just kidding guys!! LOLOLOL
Laughing Gas
Joined: Dec 2007
Posts: 796
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From: Minnesota
Does it pop up through the carb at all just off of idle? I think you have a vacuum leak from the intake gasket and its leaking to the inside of the motor under the intake. Did you use one of those metal pan gaskets for an intake gasket? I am running a 70 429 with the same heads and intake that you have, but a 750 holley and a stock cam for a 70 tbird with roller rockers. My vacuum is 18 at idle. I had tried to use the metal pan gasket in the past and it leaked. Went with the regular fel-pro ones instead. It's soo hard to keep the metal pan ones lined up. On a chevy hobby stock that my brother runs we had to use 2 intake gaskets on each side to get it to seal, but the heads had been milled.
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Does it pop up through the carb at all just off of idle? I think you have a vacuum leak from the intake gasket and its leaking to the inside of the motor under the intake. Did you use one of those metal pan gaskets for an intake gasket? I am running a 70 429 with the same heads and intake that you have, but a 750 holley and a stock cam for a 70 tbird with roller rockers. My vacuum is 18 at idle. I had tried to use the metal pan gasket in the past and it leaked. Went with the regular fel-pro ones instead. It's soo hard to keep the metal pan ones lined up. On a chevy hobby stock that my brother runs we had to use 2 intake gaskets on each side to get it to seal, but the heads had been milled.
It did pop up back through the carb a few times. but only when I shut it off.
I re-set the timming and it hasn't happened since.
I'm using the recommened FelPro gaskets for aluminum heads/aluminum intake. The guys at Fast Times said they were better then the regular stock gaskets. Hmmmm.......maybe I should change them?? My carb is a 750. I made a mistake earlier