oky doky... finally got around to compression testing, which shoulda been the first thing I did...
live and learn.

and the results;

1] ~150
2]~130
3]~150
4]~30 (yes... I checked it 4 times)
5]~160
6]~145
7]~148
8]~160

obviously #4 has a problem. I squierted a load of oil in it and rechecked it only raised it 3 or 4 lbs.
From my reading... a valve? a lifter? a pushrod bent? a badly fitted valve? (as they said the put on a "good" set of heads)

I wanna start from the least invasive trial and error repairs and progress to the big job of ripping the head/valves off both sides and putting in new everything.
I see the overall compression seems OK, or is it too varried to be "normal"?

that is the side and back I hear that TIC that everyone says in the exaust mainfold. (that noise is intermittent)

along with the general "well fellas where do I go from here/what would you do" question I wanna know will it harm the engine to continue to run it on that dead cylinder?
I dont really need the truck NOW, as I have the nissan that runs fine and is inspected till next year....so I can just park this piggy in the shade and start pulling parts... actually it will save me a good bit of cash to cancel the insurance on it, that alone will buy parts!


ok ready to get greasy... whatdoIdofirst?

my thought; take the valve pan off and see if I have a bad rod or rocker or busted spring or whatnot. Would a bad hydrolic lifter make that bad a compression reading?
If I hae to dig that far down ALL the lifters/rods/valves/ect are getting NEW replacements....
but I sure would like it to be somethin "simple"


not likely... let me dream...

 

Yes its a valvetrain problem, yes all of the above.......unfortunatley, you have to start ripping and tearing...start with the rockers, and work yor way down...A lifter could cause the problem, but would usually be very noisy...Likley a burnt/bent valve...or a round cam lobe...d44hd

 

Since the oil didn't fix it, it's a valve problem. Pull the head and stick a new valve in it. While it's off, you might as well check the guides and other valves to make sure they're in spec.

 

You're gonna be pullin' that head at least. It sounds like a burnt or bent valve like d44hd said or possibly a bad valve seat. I'm not sure how the lifter could cause this? Maybe d44hd can educate us!

 

a lifter as he says would be really noisy... the engine if you didnt see the black #4 plug and compression test it you wouldnt really pay it no mind. (cept the pft pfft exaust leak)
#5-#8 being the drivers side head, is that reading one you would while in the throes of disessembly remove and redu? 6&7 are @15 lbs different than 5&8. (or is that nitpickin?)
I have broken exaust studs on the left head so I may have to yank that one also anyhow. I guess no sense talkin till the things are off and I see what condition both sides are in.
is it normal for the compressions to vary a full 10% between cylinders? I assume you have to take into account the variables like the condition of each cyl rings, valve seats ect...
something tells me if one is that bad, the others have one foot in their grave too.

 

On a used motor, I think 10% difference in compression is normal...

Maybe a leak-down test? Loosen the rocker shaft (carefully) and remove, and pump air into the cylinder. If you hear the hissing in the carb, it's an intake valve, if it's hissing in the exhaust, it's an exhaust valve...

Once you see that the cylinder won't hold pressure with the rockers/shaft removed, it's a head problem - if it holds pressure, sounds like a rounded cam lobe.

ak

 

Hiya! I'm back online... kinda lost my cable for a while.

I thought ya would like to know what we found when we cracked the engine open... sorry I wasnt thinking "pictures" but it is still in 100 pieces so i will get some so you can toss some opinions on the condition of the pistons ect.

my mechainic is a diesel mechanic, who does fords for fun.

anyhow, the MAIN problem was a badly cracked exaust valve. the inside of the engine is impressivly clean and the tops of the scylinders were a little carboned as they should be, BUT 3 were perfectly clean and shiney which he says was bad valves and crappy ignition.
the lifter rods were nice and unbent, and since the oil was in such bad shape when I got it we are going to remove the lifters and clean those out later.

the removed heads had some flaws, most of the exaust studs were broken off, the exaust donuts were almost not there. all the little oil holes were full of sticky goo. (he claims he can completely flush the crud out of everywhere while its apart, we will see.)

I've got an almost new 4bbl intake but i have to buy a new carb for it, or rebuild the old one thats with it... another thread of endless questions yet to come

the donors heads were nice and clean, its going to get new exaust studs anyway. since all of the pistons had 130# compression cold +/- 4 #, and we got that engine tuned a bit to move the donor and it run pretty well and quietly i'm pretty sure after they come back from being checked and cleaned up, we will be back in business.

the truck had to sit because of bad weather and some other unforseen delays the mechanic came acorss elsewhere in life, but I dont need it till april anyway.

first nice day we get I will go snap some pics of the dismantled engine and its innards for everyones amusement and opinions on whats in there.

I recently developed some really bad stiffness and pain in my right sholder so I MIGHT end up giving this a good paint job and selling trading up a few yrs to get an automatic/PS/PB year without hacking up this original to get those little perks.
stay tuned... it might go up for sale this summer! I really like it but I really need one I can drive and not scream in pain doing it

I'm sure i will be able to sell trade up to a nice alternitive, maybe an early 70s ford thats just as "user freindly".

 

Wouldn't a destroyed lifter fail to open the intake valve properly? I've seen lifters that were ground short by the cam lobe, although they should make a heck of a racket.

-Scouder