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

[grumpin]

I agree!

[nic55kel]

Well back to the cylinder head.
Using a ramp I managed to wrangle it up onto the bench. Still taking it a bit easy post op.



I put a straight edge across the tops of the rocker studs and I can see that at least three of them
have lifted a bit. So I guess the thing to do is change them all out for the threaded studs to match
the intake stud on number 3. The little alignment jig I made for tapping the threads will work for
some of them and I will have to do something similar for the others.

I have a set of the chevy rocker arms so I will see how that works out.

[Gary Lewis]

Glad you are taking it easy.  

As for the studs, do you plan to change them all out?

[nic55kel]

Hi Gary,  Yes I am going to change them all. Got one done this evening and had an interesting experience.
I pulled the #4 intake stud and checked my alignment for the tap and started to make threads. Went pretty
easy for a while and then tightened right up about 2/3 done (need about an inch of thread). I thought maybe
the tap was dulling so tried a different tap and exactly the same, they were both plain HSS taps.

Now I am starting to think my alignment must be off, check and recheck but everything looks good against a
straight edge. Try a little more but the last thing I want to do is break off a tap in the head and it is feeling
close to that, but I still have 5 or 6 more threads to cut. Then I remember a third tap set I have and go find
another 7/16 - 14 tap. These taps are titanium coated, gold coloured. I try that tap and it cuts the threads
like butter. I never had much faith in those fancy gold covered drill bits and taps but maybe there is something
to them. Hopefully the tap lasts for the next 10 holes. If it does, I will be a believer.

[nic55kel]

Well finished tapping all the rocker studs. The jig I had previously made allowed me to do them all except
for the two end studs. I made up a second jig and that took care of that. I am definitely a believer in the
gold coloured tap I have been using. It was really easy to cut the threads and just as easy on the last hole
as on the first.



I have started to clean the valves. They are cleaning up nice and the sealing faces appear to be in good shape.



To clean the valve guides I decided to try a piece of nylon rope that I had made lots of little cuts on causing the
broken strands to work like a brush. Soaked in lacquer thinner and sawed back and forth in the guide it worked
very well.



A bit more cleaning and I will be able to start lapping the valves.

[Gary Lewis]

WOW!  You are doing such a thorough, and well thought out job.  

[nic55kel]

Well finally got a chance to do a little more on this project.
Been tied up with spring clean up after that long winter and cutting the grass every 3 or 4 days.
I have the cylinder head back together, I hand lapped the valves and all went well.
I experimented with cleaning the ports with a concentrated lye solution and even without a lot
of heat it worked surprisingly well
.

I pulled the manifolds out to get ready to clean them. The intake is very tarred up.







I will report on how the lye solution works out on cleaning the intake.

[Gary Lewis]

I hope the lye works for you.  That would be a simple approach.  Please record what strength you use.

[nic55kel]

I hope the lye works too.
I mixed up one cup of lye crystals with 2 litres (qts) water.
Careful to add the lye to the water, when I mixed it up it generated quite a bit of heat.
I carefully levelled up the manifold after blocking off the carb base and the vacuum tree.
Poured in the liquid and I will leave it for at least a day. It is supposed to be 90F here tomorrow
so that should help.





I will report how it works out.

[nic55kel]

Well I am really really happy with how well that worked. You can only use lye on cast iron and steel, but for those it is
superb.
I let it soak for about 2 days, I had planned on putting a bit of heat to it but it reached almost a 100F here yesterday so
I didn't bother. After letting it soak for two days I dumped most of the liquid into a pail and then flushed the manifold
with hot water. Evil looking liquid that came out hope it works as a weed killer.
Anyway below is a picture of one of the ports and the rest of the intake looks just as clean.
The before  picture for that port is a couple of posts earlier.

[Gary Lewis]

That looks great, Bob.  

[nic55kel]

Thanks Gary,

It's Alive!

Working on it when other projects and weather would allow.
Back together and runs beautifully. 19 - 20 inches vacuum at idle.





I chased all the threads and wire wheeled all the fasteners, cleaned all the surfaces etc.
Used my crane to put the head and the manifolds back on.
Made up a carb spacer gasket out of 1/8" nitrile - I think the temperatures are within its operating range.
I installed chevy 292 rocker arms.
Used the distributor rotor to tell me which cylinder to adjust the valves on.
Zero lash + 3/4 turn.
Checked for oil flow to rocker arms = good.

Well that was definitely a learning experience.
I had thought of trying to clean the gas tank but they are cheap enough I think I will just replace it.

[BigBrother-84]

nic55kel wrote

It's Alive!
[…]
I installed chevy 292 rocker arms.

Congrats!

[Gary Lewis]

I prefer this one.

Congrat's!!!

[BigBrother-84]

Gary, I didn’t know it was possible to post an animated gif!  LOL!

[Gary Lewis]

That one is "embedded", and to do so you have to tick the "Message is in HTML Format" box.  But when you do that hitting Enter doesn't get you a line feed, so you have to click Formatting then Linefeed.