All Small Six Diagnosis spark plug

[Gene 64 2dr]

Can anyone help me here identifying the problem. Almost all my plugs look the same. They all have one small dark spot located in the same area. The rest of the area seems to be pretty even in color. There also seems to be evidence of oil fouling. I have installed new valve seals but I think the valve stems I have too much wear. The head came from Faron’s old head and has a very small combustion area, about 40cc.
Any thoughts.
Gene

 

[B RON CO]

Hi, I would do a compression test and run it with a vacuum gauge. You will get a lot of information. Good luck

 

[Gene 64 2dr]

Hi, I would do a compression test and run it with a vacuum gauge. You will get a lot of information. Good luck

I know the compression is good.
A while back I got 250 from Faron (forgot his screen name). Are used it for a while but had problems with always fouling the plugs. He drag raced the engine and it had oneBadly scored cyl and needed the valve seals replaced. It ran great I kept fouling the plugs. Put his head on my other 200 and the plug fouling followed the head. I am thinking the guides must be pretty shot, My 200 head that I originally used has a low compression and I am probably going to put that back on.
I’m going to look into having it mailed to get the compression up. It cc’s at 62 with a compression around 8.5. Like to get it around 9.5. Anyone has an idea on how much to take off to get that.
Gene

 

[sixtseventwo4d]

since your pattern is across all of your plugs (even) I would look for some thing that would lend to that. Check the PCV and breather to see if your getting oil saturation introduced back into the intake. I have never come across valve guide wear that equates to your spark plug condition; a couple guides maybe but just not all, unless the head was built too loose. Check for for excessive blow-by, I'm more concerned that your rings didn't hold up to the higher compression head. The dry and wet compression test would reveal a lot here.

 

[65coupei6]

Too rich.

 

[bubba22349]

Yes you might be right from your description the valve guides could be worn enough so that there is excessive valve stem to guide clearance seen this many times, they could be repaired with bronze guides or bronze guide liners not a hard job for a good machine shop. The only way to know is to measure them, since Faron used that engine mostly as a drag racer it wouldn't be as much of a problem compared to trying to use it on the street. Years ago about 1985 or so I was having lots of trouble being able to keep the guides from wearing out with my street use vechical's that used the early style heads this is when they took the lead out of the fuel in California. About 1972 Ford had started using the Induction Hardening process on the heads valve seats to prepare for the coming unleaded fuels this worked very well. My 77 Maverick 250 had very loose valve guides due to being overheated often in its life from a cooling system problem. You could tell when it was starting to run bad the plugs were oil fowled enough that the engine started missing. Pulling out the plugs to change them they had solid black deposits much worse than yours. it was sure ready to have a new set of guide liners installed. I always checked the valve guides whenever I was doing a valve job and from doing so many heads I could quickly tell if they were worn excessively just by the feel of the valve in the guide if you have much over .0015 of clearance it is time to fix them.

It takes a .050 mill cut to get a typical late model large log head at 62 CC down to 52 CC plus depending on the head gasket you use another .020 to .025 mill cut to compensate for the extra head gasket thickness of the newer composition types . However to be more exact at getting you to 9.5 to 1 CR I would need to know what piston your using and how far its top sets in relation to the block deck (the quench distance) i.e. Piston is Down the hole, zero decked, or if the piston is setting above the deck. Best of luck

 

[Gene 64 2dr]

Thanks for the replies . I just checked the compression and I came up with .
1: 215 psi. 2: 216. 3: 220 4: 220. 5: 210. 6: 200 they all hold the pressure so I don’t think there is a problem there.
I redid the cc and it’s 62 cc’s
The pistons are 40 over flat tops so the total specs now are bore 3.72, stoke 3.126, head 62 cc, and a deck height of ,040
I came up with a 8.2 cr if I did it right
To be safe I think I’ll have 60 thou taken off and see how that goes.
You can always remove more but you can’t put it back

Thanks again
Gene

 

[wsa111]

Thanks for the replies . I just checked the compression and I came up with .
1: 215 psi. 2: 216. 3: 220 4: 220. 5: 210. 6: 200 they all hold the pressure so I don’t think there is a problem there.
I redid the cc and it’s 62 cc’s
The pistons are 40 over flat tops so the total specs now are bore 3.72, stoke 3.126, head 62 cc, and a deck height of ,040
I came up with a 8.2 cr if I did it right
To be safe I think I’ll have 60 thou taken off and see how that goes.
You can always remove more but you can’t put it back

Thanks again
Gene

Gene, your compression #'s do not jive with a 204 engine with 62 cc's in the head. Especially with the block not zero decked.
Get a Snap on gauge & check again with the throttle wide open.

 

[Gene 64 2dr]

That’s because the head that’s on the block now is Faron’s old head that cc’s out at 41 cc’s. when it was on the 250 the compression ratio was around 12.2 to 1.
When Faron had someone mill the head they messed up and took way too much off. It was fine for him for drag racing but didn’t work too well for running it on the street. I do some flying so I was able to get AV gas so I could run it on the street. In the end the engine needs to be rebuilt so I’m going back to what I had in my earlier 64 Falcon. It’s still ran mid 16’s with the compression to low. Hopefully with a higher compression I will be able to get my 65 falcon in the 16’s or lower. The car is a bit heavier.

 

[sixtseventwo4d]

are you getting any white smoke at start-up or when you accelerate after idling the engine?

 

[Gene 64 2dr]

Not that I noticed
I have a A/F sensor and a wide open it shows about 13.5. Was still trying to setup the carbs. This tri power with single Webber’s

 

[sixtseventwo4d]

If your not seeing any white smoke then oil isn't finding it's way past the valves, at least not enough to be concerned from from guide wear; and since you say your running AV fuel, I believe a whole different tune strategy is in order. Both timing and delivery. AV fuel is made to burn for a whole different set of reasons

 

[bubba22349]

Thanks for the replies . I just checked the compression and I came up with .
1: 215 psi. 2: 216. 3: 220 4: 220. 5: 210. 6: 200 they all hold the pressure so I don’t think there is a problem there.
I redid the cc and it’s 62 cc’s
The pistons are 40 over flat tops so the total specs now are bore 3.72, stoke 3.126, head 62 cc, and a deck height of ,040
I came up with a 8.2 cr if I did it right
To be safe I think I’ll have 60 thou taken off and see how that goes.
You can always remove more but you can’t put it back

Thanks again
Gene

HI Gene, I think you calculations might be off just a little I got 8.10 to 1 CR with a FelPro .050 head gasket and 62 CC head.

Here is how I got close to 9.5 to 1 CR see if it matches up what you measured.
.040 over flat top Pistons
Deck height piston .040 down the hole.
Bore 3.720
Stroke 3.126
Next If you use then Victor Renz head gasket .044 thick with a 50 CC combustion chamber you get a 9.52 to 1 compression ratio. Two ways to get there plus there are also a few others.

Mill cut of .060 gets the head down to 50 CC's & using a Victor Renz .044 head gasket gets you to 9.52 to 1 CR piston is .040 down the hole so the quench distance is .084.

Mill cut of .040 off top of the block (Zero Decked) with a 56 CC's head (Mill cut of .030) & using a FelPro .050 head gasket gets you to 9.52 to 1 CR plus gives a much better quench distance of .050 this helps fight against detination to be at .035 to .050.

Hope this is of some help. Best of luck

 

[Gene 64 2dr]

Thanks again
My old head is at the machinists
Going to remove 60 thou, will let you know how it turns out

 

[Briansshop]

Can anyone help me here identifying the problem. Almost all my plugs look the same. They all have one small dark spot located in the same area. The rest of the area seems to be pretty even in color. There also seems to be evidence of oil fouling. I have installed new valve seals but I think the valve stems I have too much wear. The head came from Faron’s old head and has a very small combustion area, about 40cc.
Any thoughts.
Gene

My plugs look the same,basically stock 200. Guides/seals was my first thought.

 

[wsa111]

Find a good machine shop & have new iron valve guides installed with valves seals with a Teflon insert.
I have had bad luck with bronze guides.
Then with tight guides a quality Serta seat & combustion chamber clearance around the intake valve you will be in great shape.

 

[Briansshop]

Got a rebuilt head ready to go on...waiting for winter down time to tackle.

 

[philford]

wow that looks pretty !

 

[philford]

Can anyone help me here identifying the problem. Almost all my plugs look the same. They all have one small dark spot located in the same area. The rest of the area seems to be pretty even in color. There also seems to be evidence of oil fouling. I have installed new valve seals but I think the valve stems I have too much wear. The head came from Faron’s old head and has a very small combustion area, about 40cc.
Any thoughts.
Gene

you have probably already covered this but I had a car that had one plug where the insulator near the center eelectrode kept cracking. it took a year or two before I discovered it had a bad head gasket and started to put my water through the tailpipe. I heard that a shop may be able to put a co sensor in the water bottle and sense leakage from the cylinder into the cooling system. if it looses water and puffs white out the tailpipe then thats perhaps obvious later in the sequence. froth in the oil filler cap is a sign as well.

 

[Gene 64 2dr]

Well I can now tell everyone exactly what the problem was.
I got my old head back took 60 thou off and like bubba said I ended up with the head at 51 cc’s as close as I can measure it. Got everything and installed and the engine works great.
As for the other head I removed the number 1 intake valve and you don’t even need a machinist to measure this to see how bad this is. You can easily see play of the valve stem in the guide. 'You can actually move it around some. Faron started out with a new head and only dragged the car. It took a beating. Maybe someday I’ll have it fixed.

Again I would like to thank everyone with their opinions.
Now to get it tune up and take a trip to the track.