Okay, this is getting so old you wouldn't believe.
Here's the retarded thing about this truck, I took a compression reading a few weeks ago, and found that ONE cylinder was only getting 30 psi. Well I thought that it would be a good idea to get my head sent off for a full rebuild. Two weeks later, the head looks beautiful, it's actually as shiny as chrome in some areas. I installed it. It ran the exact same way as before. I took another compression check, and I now have TWO dead cylinders. The number two cylinder was registering zero. I did the check again, and it registered 185. 185 is pretty good, but it doesn't make a differance when you pull off the spark plug. So it's dead. The number three cylinder is registering absolutely ZERO. Dead to the extreme. Even though it sounds like I messed up, I did put on the guage correctly the first time. I did EXACTLY what the instructions on the box told me to do. So what can be making this thing register zero, then 185? I checked for any "loose" things, like studs, and whatever. I used all of the proper torque settings in my manual, and I even used all of the proper tools. I did everything by the manual, and that is what I got. "Every manual based on a full teardown" my foot. Could the machine chop have messed up? Tomorrow, i'm going to yank off the valve cover, and see if I just have a stuck valve. Oh yeah, the only way that I can get this thing to idle, and run great is to advance the timing approx. 30 degrees. I kid you not.

Thanks for any and all help, really need it this time around. It's gotten so bad, that I've already taken it off of my insurance policy.

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

Other than a faulty compression gauge, The only thing I can think of that would cause erratic compression readings on the same cylinder would be a sticking valve, but since this is the same problem you experienced before having the head rebuilt, I would tend to think it may be your compression gauge. If you get a zero reading, you can always stick your finger over the hole to see if you actually can't feel anything, being careful of any moving parts however!!! Is it possible your cam or distributor has slipped time? Some 300's have a fiber cam gear that can loose teeth and jump time.
Don't lose hope. An engine isn't nothing more than an air pump. There's nothing magical about it. Just use your head and work the problem. Take a break and think about it if you get stumped on something. Thats about all I can think of to tell you at this point. Keep us posted.

DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.

 

[font size="1" color="#FF0000"]LAST EDITED ON 13-Aug-00 AT 02:51 PM (EST)[/font][p]Chris, what side of your distributer is the vacum advance or retard on(my truck had retard.....) also, your distrubiter may be off a tooth or two, so try moving your plug wires ahead or back instead of moving the timing, move the #1 wire to where the #5(or move the #1 back to where the #4 is) is and so on, I have had that problem a few times, and if the truck will run right with the distributer turned really far, you are actually doing the same thing, if you can get it to run right, your dist. is off a few teeth, so either fix it, or drive it and forget about it. I'm in the middle of building a roll cage in my new truck, a 99 F250 S/D 2wd with a 7.3 TD/6 speed that I bought rolled(had to replace the top of the cab anyway...) needed something to tow my tractor, and the F100 is too short to handle a 5th wheel trailer, and I got a really good deal on the F250(I traded it for a bunch of tractor work.)
Now I'm really debating about pulling the 300 or converting it to deisel....
Evan MacDonald
82 F100 FlareSide
HD 300-6
NP435(6.69 low)
2.73 Geared 9"
Blue & Silver

 

Thanks alot guys, i'll try everything you just mentioned. Good luck with the F250, but those diesel parts are expensive down here, and talk about maintenance! (Not that Ford doesn't produce the best diesel)

Goodluck, i'll post back later.

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

Well the timing is put back where it should be, and the truck seems to idle wonderfully. I took off one spark plug wire at a time, and discovered that 3&4 are not firing. Pretty weird eh? When it idles, the exhaust sound great, and the engine doesn't even tremble. I yanked off the valve cover, and discovered, that everything is up to par. All of the lifters are pumping oil up to the rockers, which is cool because this truck usually had a couple that didn't work. It doesn't smoke, and it doesn't smell badly. You can't smell the exhaust until you're about 6 inches away from it. I guess that brand new cat converter I put on really does work! Well I guess within the next couple of weeks I'll have to pull out the engine, and get it rebuilt. Bummer, my first "running" truck breaks down royally two days before I can even drive it legally on the road. Well there went the Summer fun I had planned. :-) Hopefully I'll have it on the road by Christmas.

Thanks again guys, all of your replies made alot of sense, but this one just takes the cake.

The "unsolvable riddle".

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

Hmmm, not firing eh, If I remember right, you replaced the distributer and coil, by any chance did you replace the duraspark module on the inner fender? Is the no fire at the dist. or the plug end of the wire? Want to trade for my F100?(Just Kidding)
Evan MacDonald
82 F100 FlareSide
HD 300-6
NP435(6.69 low)
2.73 Geared 9"
Blue & Silver

 

Well I replaced the coil, plugs, plug wires, and the duraspark module on the fender... :-( I'm seriously baffled as to of what this might be! I think all of the cylinders are getting spark, it's just the compression thats the problem! So an engine needs three things to run right??? Air. Fuel. Spark. Well I think i'm getting all of those, except the fuel won't compress. It's just weird how it doesn't smoke or anything, and how the valves aren't stuck. Maybe the valve seats are bad??? Could that cause a problem? It just sounds that they're not seating all of the way. If I had a bad cylinder (block wise) wouldn't it smoke? Wouldn't it be a problem that GRADUALLY got worse? This all happened in a blink of an eye you know?

Weird!

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

I am not sure of the firing order of the 300, but could you have gotten the #3 and #4 wires switched? That would make it seem that neither were putting out when you pulled the wires off.
On the other hand, since they are adjacent cylinders, there could be a problem with the block, but I wouldn't think a cracked block would cause a total loss of compression or erratic compression. I suppose you have checked for collapsed lifters? If this was the case you should have a noticeable pecking. How about lifter preload? Since this is non adjustable on a stock valvetrain engine, it will be affected by milling the heads and a valve job. Both will change the preload, and could possibly be severe enuff to hold the valves open, leaking off some compression. Preload can be adjusted by getting the appropriate length pushrods to compensate, or fitting with adjustable rocker arms.
It's kinda hard to diagnose something like this from across the country, but it's just a few ideas.

DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.

 

What exactly is lifter preload? I now know what it is caused by, but don't exactly know what it is. Can you clarify a bit more? :-) I did buy all brand new lifters, and I did notice that the new lifters were taller than the old ones. They work great, and the engine is EXTREMELY quiet. Could having them be longer mess things up? They were only longer by a half centimeter to a full one. They seemed to fit the exact same way that the old ones did. Oh yeah, the wires aren't crossed.. I checked, and checked! lol I know for sure that not a single lifter is collapsed too.

I also bought myself some new rockers, but they were absolutely identical to the old ones.

Well thanks alot for giving me that advice... I think I might be headed in the right direction!

Maybe I won't even have to take out the engine.

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

Even a millimeter longer lifter could cause the valves not to close correctly, so if you are talking a half a centimeter, then this is probably your problem. Someone help me out here because I can't find my manual, but typically when you have your rocker arms torqued down, the pushrod should have the plunger pushed down in the lifter only about .010-.020? from the top. This is lifter preload.
Valve jobs will sink the valves further into the head, increasing preload. Milling the head will increase your preload by the amount of material removed. All this plus the possibility of the wrong lifters adds up.
I would pop the cover off and check the lifters.
You can get different length pushrods to correct for a certain amount of preload, but you have to determine exactly what length you need first.
PAW and other mail order companies have pushrod length checkers to help determine what you need.
By all means verify that you have the correct lifters too. You can wipe out a cam or bend and break something if they are not right.
Good Luck and keep in touch.

DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.

 

Hey, thanks alot for all of that info man.
I'm just going to tow it over to a friends house (who is a real mechanic by trade) and give him enough money to fix it forever. He knows exactly what to do, he is trustworthy, and he has all of the appropriate tools! It would cost me twice as much money and time with me tinkering with it, and saying "I think I fixed it". lol

You know... sometimes you just need to bail out of the burning airplane! :-)

I don't think it would cost me more than a hundred, he is very affordable since we're pretty good friends!

Thanks again!

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

YAY! Well I was getting pretty close to hauling it up North to that guy, and telling him to just fix it when... My father thought that it would be good to try one last thing. He decided to loosen up the valves on the cylinder that wasn't firing, and the one with no compression. Well it started firing, and getting compression.

I guess a tight valve could prevent a spark?

Too weird, but I don't really care. It runs great now, and I'll finally get to drive it to work tomorrow.

FINALLY!

Thanks alot to everybody who has helped me for the past two and a half months!

With much gratitude,

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver

 

Someone please correct me if I am wrong here, but I don't think the 300 has an adjustable valvetrain. The rocker arms are meant to be torqued down to a specific value. If this is correct, I wouldn't drive it in this condition because the rocker arms would soon back all the way out. However it does seem that you have isolated the problem.

DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.

 

I already thought of that. We put one extra nut on top of the one that was already there so they're really locked on. They were both lock nuts with a crimped top, not the plastic ones.

Thanks for the concern, it would have been a great warning if I hadn't done anyting to it. :-)

I plan on checking them next oil change, just to be sure.

Chris
1982 F100 Flareside
300HD I-6
SROD 4speed
Blue & Silver