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Discussion Starter · #1 ·
Ok, a week ago i put in a new cam, and new heads. The 650DP Holley i have, i bought it new about 4 weeks ago. During the first little bit of the cam break in period i had the valves adjusted wrong, so it backfired quite a bit. It also spit flames out of the carb a little. Well got that fixed.
But now the sparkplug wires ar right against the headers, so i have melted 2 wires in 2 trips. I have put on other wires that arent melted all the way through for now,. I Have orderd header wrap, a type of fiberglass boot cover, as well as foil type cover to go over the 1st boot covers, so there will be 3 layers of protection. I think this will Be good enough.
NOW FOR THE REAL QUESTION:
It has started to run really rough. I mean when i floor it or even let it run past 3K RPM's It starts to back fire a little, and you can tell that it has lost some power, and is really hesitant. I have checked the plug wires, they are all going to the right plugs, fireing is in correct order. When i did the break-in, could the )mild-big) Backfires hurt my carb? Is there anyway to check this out other than pulling the carb apart? I havent had good luck with carbs at all.
Anything i sould check? Any questions you have to correctly help me?
It is a 66 289ci. It has windsor Jr. heads, slightly ported, 650DP holley, 116*duration cam .488 lift, stock bottom end, air-gap intake. Crane roller rockers (if these are hitting the cover, can this cause problems?) It also has a T-5.
 

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Pull the valve covers. Sounds to me like you lost an exhaust lobe on break-in. Check and see if anything is out of order.

You might also want to check the timing, maybe advance it forward and retard it to see if the backfire goes away.

<font size=-1>[ This Message was edited by: Fastback68 on 7/8/02 1:12am ]</font>
 

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Discussion Starter · #3 ·
How can i check to see if i lost an exhaust lobe?
then the only answer would be is to replace the cam again?
 

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Checking the cam is simple just take the valve covers off and remove the coil wire then turn the motor over and watch the rockers if one or more doesnt move as far as the others you have a missins lobe or 2 I hope its only your power valve and i hope this helps some. Brent
 

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Discussion Starter · #5 ·
ok, does the 650DP have two powervalves? and which one should i get? I live in So. Cali, near Long Beach.
 

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Discussion Starter · #6 ·
ok, does the 650DP have two powervalves? and which one should i get? I live in So. Cali, near Long Beach. Also i know that the rocker studs on the windsor Jr's (ARP Studs) should be torqued to like 60-70 with oil on them, but how can you gauge this? My torque wrench wont fit on it, since i dont have a socket long enough. I just tightened them as much as i could with a wrench, OK?
 

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If you blow the power valve the engine will be real sluggish at low rpms and will run really rich.I don't think thats whats causing your backfiring problem though.Have you checked all your vaccum lines or carb base gasket or anything intake related that could have gotten blown off from all the backfiring.Its unlikely but also check the butterflies in the carb to make sure they're not bent.If its backfiring through the carb its usually a lean condition or your ignition timing is off,or something is wrong with the intake valves(maybe adjusted too tight).I would definetly try to get your studs torqued properly,if they come loose down the road your engine will start to run like crap and finally something will break.
 

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<font size=-1>[ This Message was edited by: billy on 7/8/02 11:53pm ]</font>
 

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On 2002-07-08 01:23, andysam wrote:
ok, does the 650DP have two powervalves? and which one should i get? I live in So. Cali, near Long Beach. Also i know that the rocker studs on the windsor Jr's (ARP Studs) should be torqued to like 60-70 with oil on them, but how can you gauge this? My torque wrench wont fit on it, since i dont have a socket long enough. I just tightened them as much as i could with a wrench, OK?
Just wondering from what you said are these adjustable rockers, if they are the way you describe it. it sounds like you tightened the rockers to much.... There is a specific sequence to adj. these.... if you tightened these to say 70 foot pounds, valves are hanging open, possibly even bent valves.. Valves hanging open could cause a backfire in the carb and running rough due to poor compression....

Let me know if you are running adj. rockers and I can let you know how to adj. them....

Good Luck, Billy
 

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Discussion Starter · #10 ·
yes i am, i am running windsor Jr heads with crane roller rockers. This is what i did to adjust them. On TDC i tightened the #1 Cylinder till the pushrod was at zero lash, then 1/4 more turn. Then i rotated the crank 90* and did the next cylinder on the fireing order. And so on and so on, turning it 90* everytime. I have timing tape on it so i got the 90* turns pretty straight on.
Thanks for any more help
 

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If you bought the carb new a month or two ago it has the pv protection already installed. It should blow the pv, no matter what kind of pop or fart shoots up out the top. If you want to check it go ahead but I doubt that's it. Like it's been said before, if it's blown it will run REALLY rich on idle and smoke like a mother. The gas fumes out of the pipe on idle will be stank. Anyhow, I'm betting your rockers are off a little bit, too tight or loose I'm not sure. Now, that you've got it running, take the valve covers off and adjust them on idle. I don't have roller rockers, but a universal technique is to loosen them until the tick then tighten back up a quarter turn or so.
Double check your timing as well. I put a new cam in my car it took a little while for the distributor gear to wear into the drive gear on the cam. I had to reset it a couple of times. You might of had timing set correctly at the start, but weird things happen. Start with about 8* initial and make sure it is advancing as your rpm increases. Your timing tape should help you there. Good luck. You'll get it figured out.
 

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Discussion Starter · #12 ·
Thanks for all the help, ill keep you posted on how it turns out.
 

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On 2002-07-08 12:06, andysam wrote:
yes i am, i am running windsor Jr heads with crane roller rockers. This is what i did to adjust them. On TDC i tightened the #1 Cylinder till the pushrod was at zero lash, then 1/4 more turn. Then i rotated the crank 90* and did the next cylinder on the fireing order. And so on and so on, turning it 90* everytime. I have timing tape on it so i got the 90* turns pretty straight on.
Thanks for any more help
Here is a link to crane on adjustments...

http://64.90.9.168/cranecams/pdf/425e.pdf

I have always done it the way they are describing it.... Say you are doing the intake on #1 you turn the crank till the exhaust on #1 starts to rise, then you adjust the intake side on #1... then turn the crank again and when #1 intake starts to rise you adj. the exhuast side on #1.....

I personally have not done the adjustments they way you describe, dont know if it will make a diff., from the way you do it... But everyone I know does it the way in the Crane instructions and the way I described above....

Good Luck, Billy

Keep us posted
 

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ok when you say zero lash what do you mean by that, I always went with the hot lash method
if you tighten then downto much the plunger will just compress in the lifter and it will stick the valves open

make sure your lifters are primed up
 
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