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1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

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nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Hi Dave,

I am going to hold off on doing the others until I see how this one works out.
When I do them I will pull the cylinder head and jig it up on a drill press.
Lovely weather today so I put it all back together.
Unintentionally I found out that if the the valve adjustment is too loose it is easy to throw a pushrod.
Anyway once I had the adjustment where I thought the midpoint of the lifter plunger travel was it ran really nicely again.
I think the best way to set the clearance would be with a bleed down tool and feeler gauge.
Going to try it on a few cold starts before I get too excited but definitely making progress.

The chevy stud is just long enough as you can see in the picture.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

Well done!

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

FuzzFace2

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

So with that fix it makes the valve train adjustable right?
If so why not adjust them when running?
Back the nut off till you get a little noise, tighten the nut till it just stops making noise and then go 1/4 to no more than 1/2 a turn tighter.
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

ArdWrknTrk

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

In reply to this post by nic55kel

Tremendous that you were able to fix the pulled stud in situ Bob!

It would be reassuring if there were a few threads above the nut, but bowtie parts don't belong in a Ford anyway.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

In reply to this post by FuzzFace2

Hi Dave,

For me I don't really see any advantage to adjusting the clearance with it running and it is messy.
I just make sure the lifter is on base circle tighten to zero lash (by twisting the pushrod) and go 3/4 turn past zero lash.
Because this engine had thrown pushrods before I was tempted to go 1 full turn past zero lash but I would not want to do that without bleeding down the lifter and measuring the clearance. Going 1 full turn should not be a problem as the lifter has about 140 thou of bleed down and I just figure if I set the lifters on the tighter side there should be less chance of throwing a pushrod. When I do the rest of the studs I will measure and see how tight I can adjust them.

Gary thanks for the encouragement, I cold started it today and so far so good.

Jim, Yes it would be nice if the stud were a little longer but the locknut is fully on the threads so I don't think it is going anywhere. It was pretty straightforward after making the jig, to true the tap, that threaded the hole.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

Well done!

Gary, AKA "Gary fellow": Profile

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Well the starting has become worse and worse as the weather has become cooler. Only running on maybe 4 cylinders and shaking like a Polaroid. Once the engine is warmed up it starts to run quite smoothly although after the last cold start it has a tick again.
I have been mechanicing for a long time and this is a new one for me. Always something new to learn.

After lots of researching on bent pushrods and to paraphrase Holmes "When everything you have tried didn't fix it, whatever is left no matter how improbable must be the truth", I have come to realize the problem must be sticking valves.
Seems obvious now but hindsight and all.

So with that decided I pulled the cylinder head. The good news is that there is still cross hatching visible on the cylinder walls and so I am glad I did not decide to do bearings or whatever when I had the engine out.
I put the head on my bench and played whac-a-mole on the valves with a deadblow and bingo. The exhaust valves have a definite spring to them and reflect the hammer. The inlet valves are like hitting semi wet cement and if watching closely I can actually see them creeping back to the closed position. As you can see in the last picture it looks like tar in the inlet port.
I think what has happened is the modern fuel with its much more aggressive solvents has picked up all the varnish and other deposits in the intake manifold and allowed them to get sucked into the combustion chambers. I guess as the tar warmed up it became more fluid and the engine would start to run close to normally. Anyway I feel like the mystery is solved and when I fix it this time it will really be fixed. Lots of cleaning ahead.

Maybe something to think about for those looking to resurrect old engines.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

Yuk! That "tar" is UGLY! And it runs and drips.

Yes, I think you found a smoking gun. Or a sticking valve. Are you going to lap them, check the guides, and replace the seals while you are working on them?

Gary, AKA "Gary fellow": Profile

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Hi Gary,

Yes I will strip the head, give it a good once over and do the seals and lap the valves if indicated.
I did a compression test on the engine when it was still running good before all this mess and the readings were really good. All between 140 and 155 so can't see doing more than a quick touch up on the valves.

I think I will try oven cleaner on this tar and I also have to figure out how to clean out the intake. Brake clean doesn't seem to touch it so I think I will have to emulsify it, hence oven cleaner.

Will keep you posted.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

There is brake cleaner and BRAKE CLEANER. Brandon/Bruno2 brought some big name brake cleaner over and it wouldn't touch what I expected it to melt. I pulled out my favorite, O'Reilly's house brand, and it melted the stuff.

Anyway, good luck!

Gary, AKA "Gary fellow": Profile

FuzzFace2

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

I am with Gary that not all carb cleaner is made the same and why I go for the non-planet safe stuff.
Now if you find nothing really works what if you try and back it off / out?
I dont think most of us have ovens in our garages and you dont want it in the house oven. It will stink the oven & house and really piss off the wife.

So how about the grille you cook your burgers & dogs on?
Full tank of gas and let it cook!
Dave ----

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Hi Gary & Dave,

I agree on the brake clean, the old chlorinated was way more aggressive than the modern environmentally responsible replacement. I have both and only tried the newer stuff. Even if the brake clean worked I would need cans of the stuff to clean everything I need to clean. Hopefully I can find something that will ease getting most of this stuff off and then finish with the good brake clean.
I know that the machine shops used to use a hot caustic soda solution for hot tanking engine castings. Maybe they still do. So my thought was that is the active ingredient in oven cleaner which is readily available and cheap. I have also heard of washing soda and electrolysis but not sure if I want to try that on a cylinder head or how well it would do the internal passages.

In my first post I asked the question is the diesel fuel system compatible with gasoline?
I think I have found the answer, further thought on this makes me think that this is some kind of tank residue getting picked up by the gasoline. I did a bit of a flush but? I think part of the clean up will involve dropping the tank and inspecting.

Oh Well!

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

I'd be tempted to prop the head up and pour the passages full of something like acetone or lacquer thinner to see if it would cut the yuk over time. Go back and swirl the liquid every once in a while, and maybe pour it out and put new in if it starts cutting it.

My understanding is that most oven cleaners work best with heat. And as Dave said, if you don't have an oven in the shop your wife may not appreciate the smell and smoke that is generated if you use the oven in the house. So if you go that way his suggestion of a grill might be an option, but a 300 six's head is looooong.

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

Oops - Forgot the fuel tank. It would be reasonable to expect there to be some residue in a diesel tank, so I do believe you'll get "stuff" letting loose.

But my experience in cleaning tanks is poor. I spent about half as much as a new tank in gasoline trying to wash one out. So if you can't catch the stuff with a filter or two then I'd seriously consider a new tank.

Gary, AKA "Gary fellow": Profile

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

In reply to this post by Gary Lewis

Little bit of progress today. Thanks for the lacquer thinner suggestion Gary.
It is the best thing I have tried so far. It will cut the tar and I found that putting some on the valve stem of the stuck valves makes it much easier to remove them. Mixed with a bit of ATF it seems to liquefy the tar a bit.

I made up a valve compressor, nothing pretty but it works. The guides so far seem to be in good shape and so do the valve faces and seats.
The weather is getting cooler and not sure how much more I will get done on this before I shut it down for the winter.
But I will keep plugging along until the snow comes.

Last picture makes it easy to see why the valves were sticking.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

Glad you found something that will cut it. That's really ugly looking stuff, so getting it out of there is vital.

I hope you can get it done before the cold sets in. I hate leaving projects unfinished.

Gary, AKA "Gary fellow": Profile

grumpin

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

In reply to this post by nic55kel

Man, that’s nasty! I like the tool you made!

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Dane, Gary,

Yes it is pretty nasty but it will come out with some effort. Thanks on the valve compressor, strictly low budget around here.
I made a little progress today and got a couple of the ports fairly well cleaned up.
Work it and soften it up with a toothbrush and lacquer thinner and then work it with a scotchbrite pad. The pad soaks up the tar as it cleans it off, messy but best way I have found so far.
Still thinking about the intake manifold.

If I don't get it back together before the snow flies, it just means I will come back to it in the spring with renewed interest. My mind is already moving on to winter hobbies, electronics and ham radio, but I will keep working on this until it is too cold to enjoy it any more.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

Gary Lewis

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Administrator

Looking good, Bob.

Electronics and ham radio used to be high on the list for me as well. Got my license in '63 as WA0FFF. Knew my way around radios and TV's back then. And it makes sense that they'd be "winter hobbies" up north.

Anyway, hope you can get the head to a good stopping point. But surely the intake has the same stuff in it? Wonder if you could seal the carb opening on the intake, turn the runners vertical, and fill them up with lacquer thinner? In cold weather it might not evaporate very quickly, and you could come back every once in a while to stir it and top it up.

Gary, AKA "Gary fellow": Profile

nic55kel

Re: 1986 F-250 XLT 6.9 idi C6 switch to 300 4 speed

Thanks Gary for the encouragement.

I have sprayed everything down with rust check and covered it all so it will be waiting for me in the spring. I have too many other things I have to get done before winter. Trees to cut back etc.

Wow you became a ham in 63 back when you had to study hard for the license. This was more of a bucket list thing for me, I didn't get my ticket until 2018 after I retired. Electronics has been a life long hobby but I never knew any ham operators until later in life.
You are right it is a good winter hobby, I prefer the technical side of it, fixing radios that don't work and homebrew.
I am working on my morse code and up to making slow speed contacts, call sign is VE4RTH.

I have the winter to think up what to do with the intake. I think I will have to figure out some kind of hot tank, if I could simmer it in a drano solution I think that would probably work. I have some ideas on how to do that. Good for the cylinder head too.
I should probably contact a machine shop and see if they still hot tank and how much they would charge, but I think that was cast iron era and too aggressive for aluminum and also all the environmental concerns.

I will check in every now and then over the winter.

Bob near Winnipeg

1986 F250 Lariat extended cab 300 T18 2WD
1979 Honda CX500
1992 Oldsmobile 98 touring sedan
2007 F250 6.0 4wd

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