460 timing/idle problems
#31
What was done to the heads. If ported do you know what they flowed?
You may need to drill holes in the primary throttle plates to bring the idle feed slot in proper relation to the throttle blade which will cover the timed vacuum (if that is the one that pulled 5lbs) thus cutting vacuum to the distributor. If its a street strip venture vacuum advance might just be a waist of time. What is your manifold vacuum at idle? Not timed port.
I sugest you get one of thew books on Holly carbs such as the HP book on them. They can go into more detail with pictures and diagrams than can be accomplished here easly. From there we could comunicate better too.
You may need to drill holes in the primary throttle plates to bring the idle feed slot in proper relation to the throttle blade which will cover the timed vacuum (if that is the one that pulled 5lbs) thus cutting vacuum to the distributor. If its a street strip venture vacuum advance might just be a waist of time. What is your manifold vacuum at idle? Not timed port.
I sugest you get one of thew books on Holly carbs such as the HP book on them. They can go into more detail with pictures and diagrams than can be accomplished here easly. From there we could comunicate better too.
#32
I had my distributor reworked today. My vacuum advance canaster was bad. The mechanical advance was set to come in too early and not enough. After I put it back together I still had piston knock. A local machine shop took the time to talk to me about it and they did a little research and found that if I am running Speed Pro pistons, then I am probably no lower than 10.5:1. I went and filled up with 100 octane and the piston knock was gone. Since the 100 octane fuel is 40 miles away, I will either be changing my heads or pistons. I have two sets of D3VE heads but I would have to convert the studs in order to use my roller rockers. I keep you informed, but suggestions are welcome. Thanks for all the help everybody.
#34
My 429 runs a 292/.560 (advertised). I also have C9ve heads with portmatched runners but not really ported. With TRW L2366F pistons I'm supposed to be around 11.2/1 compression. I run up to 36 degrees total and have not had detonation issues with 93 octane. I am running one step colder on my plugs though.
I have mechanical advance and secondaries. I think your setup is close enough to mine to be able to avoid the detonation.
I have mechanical advance and secondaries. I think your setup is close enough to mine to be able to avoid the detonation.
#35
are you sure your only getting 5HG vacuum off the manifold?? my vacuum tester/fuel pressure tester says that anything between 0-10 is late valve timing, or an intake or riser leak....are u sure your timing chain was installed properly?? it could have been put in retarded 4 degrees, might need to get a degree wheel....just a thought....
i dont know what cam my 460 has, or what compression ratio its running, but i know its bored .030 over and had SOME sort of cam installed by the PO..but since i freshend it up last year i havent been able to hook up my vacuum advance at all, but even so it still runs smooth all day long, it just dont have all the power and cruising economy it should....vacuum advance is overtaken by mechanical advance, so at high rpms the VA isnt doing much if anything....anyways, your motor should be able to run smooth at idle without any vacuum advance, cause just like Bear said, there shouldn't be any vacuum at that port at idle anyways....
ive also read on here somewhere that the duraspark II box has a timing retard feature, is there any merit to this?? i really think its in the valve timing, but thats IMHO........
i dont know what cam my 460 has, or what compression ratio its running, but i know its bored .030 over and had SOME sort of cam installed by the PO..but since i freshend it up last year i havent been able to hook up my vacuum advance at all, but even so it still runs smooth all day long, it just dont have all the power and cruising economy it should....vacuum advance is overtaken by mechanical advance, so at high rpms the VA isnt doing much if anything....anyways, your motor should be able to run smooth at idle without any vacuum advance, cause just like Bear said, there shouldn't be any vacuum at that port at idle anyways....
ive also read on here somewhere that the duraspark II box has a timing retard feature, is there any merit to this?? i really think its in the valve timing, but thats IMHO........
#36
Turbo226d, I am not sure what not enough was. The old vacuum advance canister would advance my timing 20+ degrees. I did check my timing tonight myself and with the vacuum advance disconnected I am reading 17 or 18 degrees advance. I think I need someone else to check it out.
Bodabdan, I am running D0VE C heads not C9VE heads. I am not sure if they are the same or not. The D0VE C's have a 76cc chamber and the D3 heads have a 92cc chamber. If you are at 11+ cr then I should be close and should also be able to run 93 pump gas. What plugs are you running? The D0VE heads have the larger diameter thread. The local parts stores dont seem to have a clue about older V8's.
SwOkcOffRoader, My manifold vacuum is 9, my ported vacuum (the connection on the metering plate above the air mixture screws) is 5. I agree with you and also think the valve action is off. I am trying to eliminate all other possibilities before tearing down the front of the engine.
I dont suppose you guys have a trick of the trade way to verify valve action without breaking down the front of the engine do you? Keep the replies coming so far I have corrected several issues from your input. Thanks again
Bodabdan, I am running D0VE C heads not C9VE heads. I am not sure if they are the same or not. The D0VE C's have a 76cc chamber and the D3 heads have a 92cc chamber. If you are at 11+ cr then I should be close and should also be able to run 93 pump gas. What plugs are you running? The D0VE heads have the larger diameter thread. The local parts stores dont seem to have a clue about older V8's.
SwOkcOffRoader, My manifold vacuum is 9, my ported vacuum (the connection on the metering plate above the air mixture screws) is 5. I agree with you and also think the valve action is off. I am trying to eliminate all other possibilities before tearing down the front of the engine.
I dont suppose you guys have a trick of the trade way to verify valve action without breaking down the front of the engine do you? Keep the replies coming so far I have corrected several issues from your input. Thanks again
#37
Your total advance shouldnt be more than 36. 20 initial plus or minus isnt bad. that leaves 16 in the distributor at the crank which means 8 in the distributor. To achive this with a Ford distributor the advance slot has to be welded up I havent seen an advance plate marked with an 8. If they exist there a rare bird. A MSD distributor allows 9 min 18 at the crank. I have had to make my own bushings for them. With a lot of compression closer to 32 might be needed. Many of my big block boat motors run in the 32 range total.
You might just ditch the vacuum advance till the initial and mechanical look good.
You might just ditch the vacuum advance till the initial and mechanical look good.
#38
Originally Posted by SwOkcOffRoader
are you sure your only getting 5HG vacuum off the manifold?? my vacuum tester/fuel pressure tester says that anything between 0-10 is late valve timing, or an intake or riser leak....are u sure your timing chain was installed properly?? it could have been put in retarded 4 degrees, might need to get a degree wheel....just a thought....
i dont know what cam my 460 has, or what compression ratio its running, but i know its bored .030 over and had SOME sort of cam installed by the PO..but since i freshend it up last year i havent been able to hook up my vacuum advance at all, but even so it still runs smooth all day long, it just dont have all the power and cruising economy it should....vacuum advance is overtaken by mechanical advance, so at high rpms the VA isnt doing much if anything....anyways, your motor should be able to run smooth at idle without any vacuum advance, cause just like Bear said, there shouldn't be any vacuum at that port at idle anyways....
ive also read on here somewhere that the duraspark II box has a timing retard feature, is there any merit to this?? i really think its in the valve timing, but thats IMHO........
i dont know what cam my 460 has, or what compression ratio its running, but i know its bored .030 over and had SOME sort of cam installed by the PO..but since i freshend it up last year i havent been able to hook up my vacuum advance at all, but even so it still runs smooth all day long, it just dont have all the power and cruising economy it should....vacuum advance is overtaken by mechanical advance, so at high rpms the VA isnt doing much if anything....anyways, your motor should be able to run smooth at idle without any vacuum advance, cause just like Bear said, there shouldn't be any vacuum at that port at idle anyways....
ive also read on here somewhere that the duraspark II box has a timing retard feature, is there any merit to this?? i really think its in the valve timing, but thats IMHO........
#39
I honestly don't know the current part number for my plugs, but my motor was out of a 69 Lincoln. The engine is not where I am at the moment. I ask for the 69 Lincoln 429 plug number and then go one heat range colder. I suggest you avoid the guy still in high school to help with this. I have never tried a factory heat range plug so I can't say if it would make a difference or not, I just went colder for a little more safety margin. I do know that they are Bosch platinum plugs though.
When I first assembled my motor the machinist that prepped the block missed a crack in #7 cylinder during the magnaflux inspection. I lost a cylinder, rod, valve,piston, and damaged the head, as well as destroyed the spark plug. I kept the destroyed plug in my display case ( good conversation piece ) and the number on it is an NGK WR5 V-Power.
As for heads I don't really think that there is much difference if any between C9VE and D0VE. I think 72 or 73 was when C/R dropped dramatically. I have never cc'ed my heads but I want to say that the chambers are 65cc. The chambers are stock with the exception of some very minor polishing by yours truly and some 400 grit paper. and they have been milled for sealing purposes but not really shaved. If your chambers are stock and nothing has been stroked or shaved, your piston manufacturer should be able to tell you what your C/R is with their piston. BTW I am using Fel-Pro blue gaskets.
You may also try to go to a richer ( bigger) jet in the carb. Leaner is more likely to detonate than richer is. Maybe an o2 gauge could help dial you in.
I think you're really close to a killer motor if you can just fine tune a few little things and work out a few small bugs.
BTW I was running a Mallory Hyfire ignition and it worked OK, but I will be all MSD in the future. They make a good product and you can add any type of accessory known to man, at least to this man. I may have been able to go past 36* total, but I did not want to push my luck. Detonation only needs one chance to do a lot of damage.
The only other thing that comes to mind right now is the possibility of a bad transmission modulator valve causing a vacuum leak, but you will normally also suck in ATF and you'll find a dirty plug.
Good Luck!!
When I first assembled my motor the machinist that prepped the block missed a crack in #7 cylinder during the magnaflux inspection. I lost a cylinder, rod, valve,piston, and damaged the head, as well as destroyed the spark plug. I kept the destroyed plug in my display case ( good conversation piece ) and the number on it is an NGK WR5 V-Power.
As for heads I don't really think that there is much difference if any between C9VE and D0VE. I think 72 or 73 was when C/R dropped dramatically. I have never cc'ed my heads but I want to say that the chambers are 65cc. The chambers are stock with the exception of some very minor polishing by yours truly and some 400 grit paper. and they have been milled for sealing purposes but not really shaved. If your chambers are stock and nothing has been stroked or shaved, your piston manufacturer should be able to tell you what your C/R is with their piston. BTW I am using Fel-Pro blue gaskets.
You may also try to go to a richer ( bigger) jet in the carb. Leaner is more likely to detonate than richer is. Maybe an o2 gauge could help dial you in.
I think you're really close to a killer motor if you can just fine tune a few little things and work out a few small bugs.
BTW I was running a Mallory Hyfire ignition and it worked OK, but I will be all MSD in the future. They make a good product and you can add any type of accessory known to man, at least to this man. I may have been able to go past 36* total, but I did not want to push my luck. Detonation only needs one chance to do a lot of damage.
The only other thing that comes to mind right now is the possibility of a bad transmission modulator valve causing a vacuum leak, but you will normally also suck in ATF and you'll find a dirty plug.
Good Luck!!
#40
#41
Originally Posted by turbo2256d
What was done to the heads. If ported do you know what they flowed?
You may need to drill holes in the primary throttle plates to bring the idle feed slot in proper relation to the throttle blade which will cover the timed vacuum (if that is the one that pulled 5lbs) thus cutting vacuum to the distributor. If its a street strip venture vacuum advance might just be a waist of time. What is your manifold vacuum at idle? Not timed port.
I sugest you get one of thew books on Holly carbs such as the HP book on them. They can go into more detail with pictures and diagrams than can be accomplished here easly. From there we could comunicate better too.
You may need to drill holes in the primary throttle plates to bring the idle feed slot in proper relation to the throttle blade which will cover the timed vacuum (if that is the one that pulled 5lbs) thus cutting vacuum to the distributor. If its a street strip venture vacuum advance might just be a waist of time. What is your manifold vacuum at idle? Not timed port.
I sugest you get one of thew books on Holly carbs such as the HP book on them. They can go into more detail with pictures and diagrams than can be accomplished here easly. From there we could comunicate better too.
#42
I dont suppose you guys have a trick of the trade way to verify valve action without breaking down the front of the engine do you?
BTW I was running a Holley, I think it was an 830 cfm and it was great. Got it from a buddy who's in the asphalt circle track scene, so there's no telling what was already done to it, but man it really woke things up!! Tried an Edelbrock and I couldn't make it work very well at all for me. As far as I could tell I was still on the idle circuit at about 800 RPM idle, but I was all mechanical so ported vacuum I had may not work for you. Some of these guys here obviously know alot more about carbs than I do, but I would verify every bit of info I could before I modified a carb in some way that I couldn't undo.
#43
Hey guys, I already have the Holley manual. It suggested opening the rear plate with the adjusting screw. I did that and it helped. It dropped the ported vacuum from around 7 to around 4. If I have the time this weekend, I am going to pull the timing chain cover and check the cam gear alignment to see if I am a tooth off, as well as the gears to make sure that I dont have the factory retarded gears.
#44
Pulling the timing chain cover would definitely tell the tale, but I wonder if you could somehow find the high point of a cam lobe at the push rod and TDC and tell anything about your cam timing? Might save some work, but if you're like me it would take longer to do the math than to pull the cover.
Do you have access to a degree wheel? I can degree a cam but I have to relearn the procedure every time, I don't know that I could do that myself but maybe you can.
BTW what are you showing now for manifold vacuum?
Do you have access to a degree wheel? I can degree a cam but I have to relearn the procedure every time, I don't know that I could do that myself but maybe you can.
BTW what are you showing now for manifold vacuum?
#45
If anyone has the steps to do that, I would really appreciate it. I really dont want to remove the cover. This is why this thread is sooo long. My manifold vacuum is around 9. I know that is too low. I dont have a degree wheel and I really dont know how to use it anyway. I am definately willing to learn. I really want my Ford to run like I know a Ford can run.