I'd be worried wth less than 90 or 100. Pour some oil into the cyl and check right away. If it is the same, your valves aren't seating. if it raises alot, the rings are bad.
Dosnt hurt to turn engine with dist out----as long as you understand the procedure for getting to TDC on the compression stroke and getting the oil pump shaft to engage properly
I suggest you go to a cam or ford website (even here?) to understand the procedure for setting the lifter preload. Its not really rocket science, but its very important. It probably wouldnt be too clear if we attempted to explain here. If you intend to work on engines yourself, you should learn about preload. There are several things here that indicate your preload could be off----maybe not, but needs to be checked for sure. For example, new headgaskets, if the compressed thickness is different from OEM, can directly affect preload. Wrong preload gives either ticking or valves that wont close.
Thanks guys, for all the info. It definantly has to be something with the, valves because I have triple checked the timing. It still though is crazy to me that yesterday it was backfiring through the carb and today its the exhaust. I will pull the intake, and learn about pre-load and hopefully i will get all this trouble corralled into one spot. Thanks again guys, I guess my fun is still aways away.
Ok, guys I am still thinking about what all you said. I talked to some fellas at work and they all agree that it is something with the valves not closing all the way. So I need to check preload, can anyone tell me the preload setting for Speedpro(Federal Mogul) lifters. Also can I check the preload with only the valve covers off, or do I ruin my new gasket under my intake and pull it off to get to the lifters.
You will have to get the (all) cylinder at TDC of the compression stroke (both valves closed, lifters on the base circle of the cam). There is a way to check several cylinders at one setting, as several cylinders can be checked at the same time---I just dont recall that procedure.
Loosen and back off each rocker arm bolt a couple of turns on both rocker arms/pedestals (I & E). As you tighten the bolt back down, turn the pushrod with your fingers. You can feel when the pushrod gets tightened and cant be turned, no gorilla fists!! You should be able to do it without pulling the intake.
You should then have to turn the bolt down more to tighten the pedestal down tight. This is where someone else will have to help, I dont recall the amount of extra turn is correct for preload. Too much more turn will not let the lifter fully extend and will keep the valve from seating. If it takes too much to tighten the pedestal down on the seat, you will have to install a shim (kits available from all cam mfg's) between the pedestal and its seat (slot on the head). You have to check this for all cylinders and all valves.
The object of this little game is to compress the "cup" in the top of your lifter down a few thousands so that all slack will be out of the pushrod when running, but not so much that the lifter will not extend correctly.
I suggest, if its your first time, be prepared to take a little time doing this or get someone who is familiar with the procedure. I am sure there better ways to describe this process----sorry "bout" that, but this may give you some idea. Search a little bit, there are many procedures written on this subject-----LOL
Hey guys an update on what I found this evening. Thanks benshere on that procedure. Ok the problems. I set the engine toTDC pulled the distributor and put on a different VAC advance in case the old was frozen in an advance state. While the distributor was out I rotated the engine and found out that there is half a tooth missing on the cam. I don't think there is enough missing too matter, but I don't know. Also, there seems to be a big gap between the intake and the block. I don't know if it is leaking there or not( can't get the engine started to tell). So after finding these problems, I reinstalled the distributor and tried to start it. Now the engine isn't firing at all. I through the 1/2 inch wrench that was in my hand and came in to watch survivor. So were still trying.
It sounds to me like when you had everything installed the first time that it was backfiring through the intake valve(s). Now you atleast have it backfiring in the direction it is supposed to be flowing. What exactly is going on I am not sure. I know that it does sound as if you are getting a fuel load up while cranking. Then the backfire comes from the ignition of that load. Does the motor even sound like it is trying to start or is it just the backfiring? I know this is probably a dumb question but have you double checked the plug wires to make sure you don't have one crossed? When I put the new 351m in my truck I had a problem with it backfiring throught the carb. I played with timing and carb settings and it took a little bit but I got it to quit. The new carb may be setup different than for what you are running. It may be set up for high performance. I did have the advantage that mine would start and would backfire through the carb when I stepped on it so I could make adjustments and test drive. How many miles are on the timing chain in the engine? It is possible it could be stretched and messing up the timing. Were the lifters new? If not one of them may not be working right and holding a valve open. I know that you have probably thought of most of this, sometimes it is easy to overlook something when you are frustrated. I know that from experience. I hope something I have mentioned helps. Good luck.
Throttle back fellas. If I read correctly, you started your timing adjusting at TDC...? If this is a correct statement then you might want to re-attack the timing. You need to set your distributer to around 8 BTDC and go from there. These motors are manufactured to start your fine tuning from that point..if you set it to TDC right off the bat you won't even idle properly....the closer you get to where you need to be will result in good idle, good acceleration, and once you mash the throttle you may get a "pop"...just make fine adjustments from there. If I read wrong, I apologize. Good luck..actually no luck is required.
I would start by making sur that your lifter preload is correct. After the push rod is snug like benshere stated then turn the nut another I believe 1/4 turn. adjust each cylinder in firing order at tdc. As for the gap between the intake this should not stop it for running although it may run poorly.
I went back and read some of your posts. I really doubt that the preload is too tight, holding the valves open. Maybe the preload isnt exactly right, but on a worn OEM engine, I dont think that is your immediate problem.
Unless, on some of your backfires, you jumped the timing chain a tooth or so (I think the 78's still had the nylon cam gear--which could be well worn) I cant see anything that would cause your problems. Lots of wear makes them run less than perfect, but not quit----well sometimes!
Are you sure the cam is even turning at all? Pull the valve covers and dist cap and plugs and have someone turn the engine over w/starter while you watch the rockers and the dist rotor. I did something really stoopid years ago, (I aint tellin) and broke a timing chain (while running). Knock on wood, no valves hit pistons. I am not admitting anything, but can tell you that that little screw on a screw type hose clamp will get between the gears and the chain-----POP!
I am really thinking you have a problem with the firing of the right plug at the right time. Lots of other possibilities, but I doubt it. Go for a nice long walk while a knowledgeable friend (or trusted ememy for that matter) checks it over
If I read correctly, you starting your timing mark at TDC...this is wrong. These motors are set to factory at around 8 degrees Btdc as a starting point. I would re-address your timing at this point and see if this helps. Setting your balancer @ TDC...you would have trouble giving it gas from idle. If I didn't read your thread right, then I apologize.
Using TDC (on the compression stroke) is only for determining where the cam is for setting lifter preload in this case. TDC should put both I &E lifters on the base circle. I dont think these OEM cams have any overlap on either at TDC. TDC is only as a reference point.
To set timing, I would go to 10-12 deg BTDC, but even when timing is set at TDC I have never seen it cause these kinds of problems. Run poorly, no power, but not backfiring. 8 or 10 deg either was on these low comp small cam engines isnt gonna make a he##uva lot of difference----in my opinion Maybe on a High compression, cammed to the max high perf or race engine this timing might.
I am thinking the problem is in the electronics, wiring, dist------somewhere!
Hey Guys thanks again for all the post. I have another question. I want to know what a good cam is that is just above oem that I don't have to change valve springs with. As for the problems before, I am still mad at it so I haven't been out working on it. I think I am going to tear it back down and put a cam and new lifters in again. Also a new timing chain, and gears with a new balancer. First of all I am going to put the old cap on and see if the new cap and rotor is the problem. I will try and keep in touch a little better.
hmmm stock valve springs go up to .500" after that its the break dance! well go with the comp cam ex256h, good luck
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Maybe on a High compression, cammed to the max high perf or race engine this timing might.
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