Engine Engine rebuild suggestions

[manicmechanic007]

One thing to remember when cutting threads
The tap or die, not only cuts threads, but it re positions (bends) the metal at the same time
It needs lubrication (cutting oil) and to be backed up a quarter turn about every 3/4 turns
Glad you got it done

 

[JulianR]

Thanks for the tip. I was smart enough to use WD-40 as cutting oil, but I learned about the 3/4 turn 1/4 turn only after, by watching youtube

 

[85GTStangGuy]

I was smart enough to use WD-40 as cutting oil, but I learned about the 3/4 turn 1/4 turn only after, by watching youtube

WD-40 probably worked okay since it was a relatively soft material you were tapping. Would not recommend it for a harder material, like steel. And absolutely not for even harder materials, like stainless steel or a hardened steel. For those, use a dedicated tapping oil, like Tap Magic or some equal.

 

[JulianR]

One more thing-- I ended up buying a new ACT and Coolant Temp Sensor from LMR. Came as a kit for under $30. Figure it's worth changing them now as long as I got everything apart.

 

[JulianR]

Alright, so went to set the lifter preload last night. Set all valves to 0 lash and after that, all 15 rockers torqued to 19 ft lbs within 1/4-1 turn. Most in 3/4 turn. However, one pushrod, on cylinder 5, I can't get to snug up. It does NOT move up and down, but it does spin kind of freely, even when the rocker is torqued to 21 ft lbs. Now, keep in mind, my lifters haven't seen oil yet, but unlike my other other lifters, I can't seem to get this one to pre-load. What are my options?

From what I can think:
1. Maybe it'll snug up once the lifters see oil and I'm overthinking it? However, it'd still be different from others.
2. I could look for a bigger pushrod, but isn't it odd to have 1 pushrod a different size? Besides, the pushrods being sold are in 0.050 increments, and I'm afraid I need something less.

What do you suggest?

 

[General karthief]

Run with it, if it ticks then deal with it,

 

[JulianR]

Hi,

Getting to the point where I can prime the engine with oil on the stand. Do I need to hook up an oil pressure gage or just simply seeing the oil come through the pushrods is enough indicator that I'll be alright?

 

[General karthief]

I stuck a mechanical gauge on but I don't recall pay'n any attention to it. Oil came out the push rods/rockers really good so I sent it, didn't think twice

 

[manicmechanic007]

You will have to put something in that oil pressure sender hole
Otherwise, all of the oil will squirt out right there
Might just as well plug the hole with a gauge if you have one
It should build some pretty big pressure if you use a drill

 

[JulianR]

there's an electronic sending unit in that hole, right? Should be plugged up with that. Only other hole is the dipstick that I already plugged in.

 

[manicmechanic007]

Right, if the sender is there you are okay to prime it

 

[manicmechanic007]

While priming
You can watch your oil level in the pan go down some as you get the filter and all the passages full of oil
I usually rotate the crank around twice and land back on 10 before so I can set the distributor later

 

[JulianR]

Really want to add oil and prime the engine, but wanted to do a leak down test (and try my new set) first. Did not expect it would be this hard to find an adapter that screws in to the P heads highly recessed spark plug holes Got one more trick up my sleeve. Hope it works soon

 

[JulianR]

So here are my latest troubles in paradise. I bought some "spark plug non-foulers" from autozone for the explorer and was able to hook up the leak down tester hose to the spark plug hole.

Testing about 4-5 cylinders, most of them were at about 50% loss and I think they all had air coming out of the Intake runner. (I haven the intake manifolds off) I did make sure that I was on the compression stroke and at TDC. When the hose was hooked up to the cylinder, I rotated the crank until air came out of the hose, then on to TDC from there. The most input PSI I could get, for some reason, was about 65-70, though at the compressor it showed 100. The output from the cylinder would show 30-45psi. Only the first cylinder had decent numbers, the rest, I could feel the air gushing from the intake runners. I plan to re-do the test and actually write down the readings on all cylinders, but that first crack at it didn't look good.

Doing some research, people suggest these readings could be because the valve could be burnt, bent, or the timing is off. Now I did get these heads of marketplace, but they were advertised as bolt-on and go.

I rebuilt the heads as you recall myself, cleaning the valves and lapping them. Springs are the TFS stronger springs as well. Although the lifter preload is set, I still don't have oil in the engine, so the lifters aren't keeping the valves open. Obviously, none of the valves looked bent visually, or I would have caught it. There was no damage to the valves either. Although I don't think I took a picture of the timing chain I put on (new), I do recall making sure the timing marks lined up. During the leak down test, the long bar on the crank did try to move and I had to hold it-- so there is compression.

What are the chances both heads have issues with valves not sealing, especially intake. Also, I tried turning the engine over by hand, at low psi, to see if the air in the intake runner would stop hissing and seal (i.e. timing is off) and there was no point when it'd seal.

Any idea what's wrong?

 

[Noobz347]

I don't know...

What I do know is that I would take the heads to a machine shop for inspection to eliminate the possibility of trouble there.

 

[manicmechanic007]

You are cranking the engine over with the starter when checking the compression right?
You do not need the intake manifold on there to do a compression test, but is it on there, or off of there?
Are you trying to start the engine or just looking it over or testing?

 

[JulianR]

The engine is still on the stand. I'm not doing a compression test. I'm doing a Leak Down Test. Cranking by hand until TDC of the cylinder i"m testing.

 

[JulianR]

Just tested all cylinders with the Leak Down Test and here's how the values came out. The picture is looking at the engine front-- so left side is passenger, right is driver. The top numbers are the input PSI, bottom numbers are the cylinder PSI. All of the cylinders leak air from the intake runner. I was able to roll the engine over just enough to seal the Intake valve fully, but right away the exhaust would start letting out air. I am running the TFS stage 1 cam. Maybe it's designed to seal for a split second. I'm going to give them a call next. What thoughts do you guys have?

 

[AeroCoupe]

If it were me I would back all the rockers off and retest. This way you know they are supposed to be closed.

 

[JulianR]

Well, had a moment to play with it. Backed out all the lifter preload, still can't get the intake valve to seal at the proper time.

I ended up hooking up the leak down tester and running only like 20 psi of air in to the cylinder. Enough to hear it but not enough to do the actual test. I then slowly spun the engine around by hand, several revolutions, both listening to the hissing and, since I don't have the intake manifold on, watching the lifters raise and fall. Also, I decided to try it on the the worst cylinder. The one that had the previous leak down test of 72psi being put in and only reading 20 psi staying in.

As I turned the crank, very slowly, there is one very small moment where the intake valve seals and no air comes out of the runner, but, instantly, the exhaust opens and the air starts coming out of exhaust. Even looking at the 4 stroke animations, it seems there should be a good amount of time that both intake and exhaust valves are sealed as the piston compresses the mixture. I don't have that.

Here are some things I'm thinking-- before I pull the head off.

1. The heads came from marketplace with the TFS stronger springs already installed. I took them off during cleaning, re-measured the height and re-shimmed as required. If I recall, most places required 1 more 0.015 shim then they previously had. Could I have messed something up here that would cause my issue?

2. In the TFS spring instructions, it said the keepers for the springs come in 2 bags-- 1 for exhaust, one for intake. The keepers were already on the valves when I got the heads. Could the previous owner have mixed them up? Would that cause my issue?

3. Can the cam be so much defective that it doesn't open/close the valves at the right time? Does that even happen?

Any other ideas? Thank you!