460 Timing? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Sand1 · 03-28-2007, 20:17

Ok, I'm lost. Heres the deal, 460 w/ flat top pistons, 562/562 244/244 @050 lift. 75 cc Edelbrock heads, Crane gold 1:73 rockers, Weiand Stealth Intake, 950 cfm carb, oem style Accel distributor, MSD ignition Compression figures around 11:1+, running 110 octane fuel. Engine ran good with previous cam. Install new cam, problems begin. Engine to lean, new carb. Still cannot get the timing right. Advance the crap out of it and it runs almost decent but kicks back when trying to start. Timing marks on new fluid damper are way advanced if you throw a light on it. OEM balancer was the same and thought it had slipped. Cam is in straight up position. I cant figure it out or its right in front of my face and I cant see it.

Suggestions?

Paul Kane · 03-29-2007, 18:14

Check all electrical wiring associated with the ignition system. Check that cam is straight up while #1 piston (passenger side front cylinder) is at TDC, and then check distributor rotor position on the distributor. At this time, also check that the balancer is degreed correctly and that the "0" lines up with the pointer.

Paul

Sand1 · 03-29-2007, 23:49

I understand slammed lol. Were getting busy now that the weather has let up. I have been over everything I can think of several times. I did tear it back down this evening to verify timing marks and such. It was set in the straight up position. I was comparing the old Lunati to this new Comp cam and there are some big differences in them. For one, the Comp cam opens the intake valve at 40 BTDC / closes 72 ABDC. The Lunati opens the intake at 0 BTDC / closes at 34 ABDC. I guess that would explain why it idles so much advanced. I'm ready to pull the cam out and toss it in the dumpster. It ran better when I had it retarded 4 degrees. I have been looking at a Split duration Lunati, and as it stands I am only the intake bolts away from a cam change right now, its VERY tempting. I'm not liking this Comp cam at all. The Lunati Im looking at it one of their Voodoo series cams.

http://static.summitracing.com/globa.../lun-61605.pdf

I just dont know what to think about the current cam. I'll check a few more things and make a decision tommorow on yanking it out in place of the new Lunati. It's leaning that way real hard lol. If something does not show its ugly head as the source of the problems, then Comp Cams has lost a customer.

Sand1 · 03-30-2007, 17:25

OK, here are the preliminary findings on the tear down, again.
1) Timing chain grabbed oil slinger and had a little scuffle with it. On backwards, I should have been wearing my reading glasses lol.
2) while taking the #3 rocker arms loose, the #4 exhaust valve pops closed. It was hanging up. Intermittent chirp diagnosed!
3)Pulled cam and inspected lobes. Everything looks good. Nice smooth even wear.
4)Pulled right side head to inspect for damage to #4 exhaust valve. Pulled spring, valve moves freely with no binding or scars, valve guide looks like it should, (new). (Suspect lifter was sticking)
5) noticed spark plug electrode was not protruding into combustion chamber. Wrong type plugs! Had RV-12YC instead of RC-12YC.

Plan of action:
1) Since the engine is tore apart I am going to install the Lunati cam, lifters, new retainers and 10 degree locks. ALL WILL BE LUNATI
2) drop head off at machine shop to have checked by a pro. If problems are found will take the other head in for a check up as well.
3)Put it all back together using the PROPER spark plugs. I'm only human and subject to doing dumb things ok lol.
4) finish a few odds and ends and go racing!

Conclusion: A bad lifter from Comp Cams and the wrong spark plugs made for a lot of head scratching and cursing. I'm off to Summit to spend some money lol.

Sand1 · 03-30-2007, 19:18

On second thought...I was sitting here looking at the Lunati cam and thinking about the engine. I have come to the conclusion that the valve in the #4 cylinder was not sticking, but closed because it was the last set of valves still tight. I figure the spring pressure simply rotated the cam and closed the valve. Makes more sense than a lifter sticking.

I think my whole problem was the wrong plugs. The intermittent chirping would be pressure slipping past a tapered plug whereas a gasket style plug would have made a better seal. And of course the electrode not exposed in the cylinder would account for a lot of performance issues. I'm going to temp fate and put it all back together and see how things go with the correct plugs.

If your wondering how much difference there is in the plugs, its nearly 1/2 an inch. I used standard 460 style plugs thinking the heads used the same. The new heads use a 3/4 long thread and gasket instead of the short thread tapered plug. The electrode was quite literally still inside the threaded part of the head. It's a wonder it ran at all. I'll run a tap down the threads to clean the carbon out before putting them back on.

Sand1 · 03-31-2007, 20:27

ITS ALIVE lol. Slaved all day putting it back together. Its a little hateful when its cold so it takes a few minutes for things to calm down. Once warmed up, and a little tuning it was running about like it should. What...a...relief!

I think I got carried away with the carb I selected though. Cant bring the idle down below 1100 rpm or it will fall off a bit and just die. May be some more adjustments on this carb I am not familiar with too.

Worst case scenario on the carb is to sell it and buy an 850. I hope my engine problems have been entertaining to read, but mostly I hope that my experiences have been educational. I figure if by posting on this site I can prevent one person from having the same problems it will be time well spent.

I write off these kinds of things to learning and racing. But it does not make it any less aggravating trying to figure it out lol. Now I know!

Thanks Paul!

Sand1 · 03-31-2007, 23:22

On to the carburetor. In thinking I may have overdone it on the carb (pretty sure I did) selection, I have a few thoughts. I can swap out the main body for an 850 easliy enough. I'm wondering if a 780 cfm would work ok. I have a 4160 780 that ran lean on the engine. Would a 4150 780 do the job? Or would it be best to stay with the 850 plans? I'm in uncharted territory with this four corner idle deal.

Paul Kane · 04-01-2007, 21:11

The incorrect spark plugs that effectively buried the electrode in the plug holes probably hurt things pretty bad.

If you are running a double-roller timing chain, the slinger is not needed and you might be better off removing it next time you have the front cover off.

Based on the cylinder head inspection, it sounds as though your valves are not sticking but that you may have seen a valve snap shut for other reasons of which there are many (don't worry about it right now).

The 950HP should work very well on your engine and probably needs more adjusting. Play with the settings. Why does the engine die below 100 rpm? Flooding, no air? Mixture too lean? Is it possible that in order to get the idle below 1100 rpm, the throttle blades must be fully closed and so the engine can't breath and just floods itself out? Some people with big cam engines need to drill 1/16" holes (or bigger) in their primary throttle blades in order for air to pass through adequately. (Holley even sells throttle plates that are pre-drilled.) Get the engine running at idle as well as you can and then shut off the engine and look down the carburetor and determine the position of the throttle plates relative to the idle transfer slots in the carburetor, then determine if you are flooding the engine because the throttle plates are fully closed. If this is the case, then maybe you need to drill the plates in order for air to pass through the throttle plates and into the engine.

Paul

Sand1 · 04-01-2007, 21:31

That sounds logical. I did notice that when I pulled the dis vac line off it really seemed to like that breath of air. I also printed out a bunch of info from the Holley site and learned some things about tuning the beast. I never knew to adjust the rear blades along with the front ones.

Well, at least I am figuring out what its like to be a student again lol. I have to say this is the biggest and baddest engine I have ever built. So I'm in a learning curve here. Its fun, but I have to keep in mind I'm in over my head on some aspects of it.

Thats what brought me to this forum. I was looking for those who knew what I didnt. I'll check it out this week and see what I can find. The engine seems to like this carb, its not shy about revving when you slam the throttle all the way back. It doesnt hesitate one little bit.

Its starting to get an attitude, or maybe I'm just thrilled that it isnt screwed up lol.

Sand1 · 04-02-2007, 19:59

Ok, I guess I need to punch out the throttle plates so it will idle down. I put a vacuum gauge on it today and tuned and tuned. Still couldnt get it below 1000 rpm. I drudged up some info on drilling the plates. I will be starting with a 1/16 drill bit and drilling the hole on the opposite side of the plate opening.

This should prove easy work for my high torque Milwaukee drill that has been known to bust me upside the head or nearly break my wrist with a 1/2 drill bit going through heavy steel or the dreaded 2 inch hole saw lol.