Gonna get a bit long winded, so bear with me.

It all started out with pulling the C-6 out of my '86 F-150 and putting in an AOD. The main reason was to get the rpms down on the highway. With the C-6 at 70 mph, the engine was at 3k. No need to spin a 351w that high while cruising. So seeing the converter was on it's way out, I decided that money was better spent on putting towards rebuilding an AOD.

Got the AOD and rebuild it, along with a Transgo re-programmer kit and all was good, or so I thought until I hit the highway. The truck has 3.50 gears in it, so now doing 55 mph, the engine is at 1500 rpms. Great, right? Nope. The thing just falls on it's face when trying to accelerate. Absolutely no torque to accelerate.

When I got this truck, I knew it had a rebuilt engine, but never knew what was in it, just ran it. Decided to pull the top end apart and check things out. After going through things, it was decided that a new cam was in order. Did a bunch of research, and decided with a Comp Cams Extreme energy cam. COMP Cams Xtreme Energy Camshafts 35-230-3 - Free Shipping on Orders Over $99 at Summit Racing
Got new lifters, break-in oil and all related parts to do the job.

Looking at the left head, there was a sunken valve seat. Took the head in to get the seat cut out and a new one put in. Upon the machinists quest in doing the work, he couldn't do another grind on the valve that went with that seat. Ordered another valve, no problem. Now, he didn't check the valve stem diameter and found out that valves with oversized stems were put in after it had arrived. Time to cut out the valve guide and install a stock sized one, no problem again.

Got the head back, cleaned it up and went on to assemble it. Got to the valve he did all the work on and noticed it seemed a bit tight. Well, I'm no machinist so trusted his work, and he came highly recommended for head work from several people. (Mistake #1) Got everything back together and time for cam break-in after priming the oil system. While running, it started to make a ticking sound. At first, it just sounded like a lifter didn't get enough oil to fill it yet, but it continued. Checked for exhaust leaks, none. Pulled valve covers to check rockers and such, all looked good. Closed it back up and went for a quick ride. (Mistake #2)

Made great power right from idle. Went down the ramp to get on the highway. When the trans shifted into overdrive, the whole truck shook like a banshee. At first, I was thinking the trans went ( I was on it pretty hard). Slowed down and dropped into third. Things smoothed out somewhat, so I limped it home. On the short limp home, it was decided it was the engine, not the trans.

First thing when I pulled into the shop was a compression check. All good, but #6 (the one the valve work was done on) was showing zero. Pull valve cover and see that valve stuck open. Crap. Tear the left side of the engine apart and here's what I found:







That just made my day. Couldn't even get mad about it. Took the head back to the shop and showed it to the guy that did the work. He was very apologetic and said he'd make it right. Ordered another new valve, re-sized the guide, etc, etc.

So now it's back up and running.....with a tick. Only does it when warm or hot. When it's cold, it's quiet as can be. Now to pull it apart again to replace the new lifter that got damaged. I thought the bent pushrod would have saved it (mistake #3).

I am truly amazed that with how many engines I've built through the years and how much I just plain abuse them, this is the FIRST problem I've ever had with internals.

That bent pushrod? That sucker is getting framed.

On the good side, that little 351 now pulls like a mule.

 

Yeah buddy I use to have a 351 Windsor. In fact the truck I have, the 1985 Ford F-150 XLT Lariat Shortbed 2WD Pick-Up, had that motor in it which is now the truck I have plans on putting my 460 in. Its a short story in fact. The 2nd day I had the truck a mechanic at my work was doing a tune up on it for me and he dropped a stud from the air cleaner assembly into the carburetor and didn't realize it. The motor started knocking really loud. That little 1-Inch stud broke one piston apart from the connecting rod and chipped another. Not to mention how bad it scarred up the cylinder walls and head surface. I decided to rebuild a 460 to go back in it.

 

Oh man, what a tale of woe.
My sympathy.

Did you consider just changing the R&P?
Why did you decide to go with the Aod?

 

Yea I considered it, but I had that 460 block and I wanted to take that chance to rebuild it the way I want and drop it in there.

 

Wish my rpms were that low at 55mph. I thought AOD but don't want to change everything doing some reading on tightening up the C6 to have not as much slip to try and drop the rpms down if still not low enough thought of a Gearvendors unit.


on topic how ever, what are you going to do about the piston? Just let it ride?

 

There lies the biggest problem. I smoothed out the eye mark on the piston for now. It should last for a year or so, maybe longer. The current engine is bored .040, has lots of head work done. This engine is going to turn into scrap iron and another one built. This spring, I'm going to locate a good core and do the build the truck deserves. Even the heads are not worth sticking more money into with all they would take to get correct.

ArdWrknTrk - I thought about changing gears, but the 3.00 ratio is really hard to find ('80-'81 only) for dana 44. The main reason for the AOD is overdrive, I can build them tough enough and there's a lot of them out there yet. I originally was going to go with a 5-speed manual, but took the cheaper and easier way out.
This is what I like the most, with the C-6, the engine would be over 3k.

 

Yep mine would be just a hair past 2500 at that speed with my C6 and the 2.75 gears.


Would like to have mine able to run 80 turning under 2500 rpm.

 

Wow, 2.75 gears? I haven't seen a set of those in years. Maybe next time I go for a good run, I'll see where it's running at 80 mph.

 

Yep, they are hard to find, I find them for cars quite a bit on ebay used. I been wanting to find a set on ebay so I can build a trutrac center chunk to swap in and keep my OEM one as a back up.

 

Should have filled the nick in the piston with JB weld LOL.

Rebuilt heads, even brand new heads should always be disassembled to check for crap like that. My dad got burned at work once with a rebuilt head that had a cracked guide causing the valve to hang up, had to rip it all back apart. Easier to double check someones work before it goes together than find out the hard way. Same goes with new oil pumps, too. Always make sure they're OK inside before installing. There could be metal shavings in them for all you know.

Btw, you used the same cam as I did. I really enjoy it

 

I see you have rotators on the exhaust valves.
Not all heads come with them.
Good for stock engines.
Not so good for high rpm's.
If you are going to stay stock, I would keep the heads in case the new ones do not have them.
They use a different size spring also.
Just make sure the springs are still good and the rotators...rotate!

 

What problem would that little nick in the top of the piston cause? I can't think of any.

 

Take off any sharp edge, hot spot, and let her run is what I would do.
Dave ----

 

The nick if its bad enough could cause a hotspot which would cause a misfire in some cases.


Also on some pistons Ive heard its real common with hyperuetic pistons that a nick like that could cause the piston to come apart over time.






I also agree with double checking the work. The engine build I have planned I planned on buying the parts and building myself over time. Down side is when I have the block machined I have to double check it cause at work Ive seen machined blocks where the bore is actually tapered and would smoke and burn oil like crazy but not foul the plugs out. Ive also just this pack week found out that heads we had built for a engine rebuild that was done every cylinder had one incorrect valve seal that was too tall and got smashed by the keeper and resulted in the engine just pouring smoke out. Engine actually consumed two quarts of oil in 30 minutes run time.

 

When this engine comes apart for good, I'm going to strip the heads and save the rotators, locks and springs...just for the heck of it. Never know when you'll need a set. The valves will go for scrap too since they can't be ground again.

That's pretty much what I did. Sanded the sharp edges off and let her run.

The next engine is going to get machine work done by a completely different guy. The problem is, he's two+ hours away. I really think it's worth it though. This guy really knows his stuff, and Ford engines. I've seen and driven a couple of the engines he's built and to say I'm impressed is an understatement.