Head is off..questions & more questions..lots of questio

[Anonymous]

history/Issues: low compression on a couple cylinders and pretty much not firing #2 at all (spark but no bang)

Pulled the intake, header, and head tonight. Besides what looks like blown headgasket areas, I don't SEE anything that stands out. Moderate carbon buildup (ran really rich for a while), valves all LOOK about the same and seat about the same. Pistons all about the same too.

Questions:

- could blown headgasket yield low compression (I know the answer is yes) BUT could it do it without running hot or mixing fluids (coolant/oil)? I had no other symptoms

- could blown headgasket keep a cylinder from firing if there was spark to the hole? I was able to pull the plug wire off while running and it never changed the idle. Did for every other cylinder

- I found a BAD intake leak right at #2 intake runner a week ago (about when things started getting worse). Could a bad intake leak (especially right at the weakest cylinder) yield no bang there?

- I know there was spark to the plug BUT I have started seeing some arcing of spark lately from the coil boot out to the coil terminals and even from the spark boot (not sure which cylinder) to the block. I have good 8mm wires on my MSD but I guess I need better. If I pull a plug wire off while it's running, the coil arcs practically every time that cylinder would fire. Like the spark didn't have any where to go out te plug wire, so it popped at the coil. Makes sense? Just bad wires?

- can you test for bad rings with a head off? Should I be popping the pistons out to check the rings?

- can you check for valve's seating fully? They LOOK like they do, but that means nothing.


I'm thinking of taking the head to be ceramic coated to match the OZ intake. Might look really cool.


Thanks all.

 

[wsa111]

Bryce, since you found a blown head gasket & a leaking intake gasket that would kill power to # 2 cylinder.
If the cylinder walls look ok, no score marks, use a victor head gasket from napa, this is the thinest gasket right now till mike at fordsix parts gets the corteco gaskets. fix the intake leak & you should be back in business.
I think you need to change transmission shops for the C-4 trans is a very durable unit, especially behind a six cylinder. Keep us informed. William

 

[Anonymous]

transmission shop? I don't need no stinking transmission shop! I did it all myself...TWICE! Oh, maybe thats the problem.

The cylinder walls seem fine across the board.

Thanks William

 

[addo]

Can you quantify the wall finish? Many newer rings require a much finer finish hone (400 grit) than the old style units.

Did you resolve the valve lift/coil bind issue? Have you checked every one of the cam lobes? You need to, given what went on.

Just some things to check.

 

[Anonymous]

Thanks Addo. I put new high lift Crow springs in. Hadn't had the same problem as before again. I was contemplating pulling the cam at this point as well. Really would be silly not to right?

How would I "quantify" the wall finish? Very smooth?

 

[80broncoman]

Have you checked every one of the cam lobes? You need to, given what went on.

Dont overlook this one If you lose a lobe especally a intake no fuel and air and a dead cyl to go with it

 

[Mustangaroo]

- I found a BAD intake leak right at #2 intake runner a week ago (about when things started getting worse). Could a bad intake leak (especially right at the weakest cylinder) yield no bang there?

First off if you pull a plug wire and nothing happens, check the spark plug or replace the plug if it still doesn't fire then you probably have one or more intake leaks in your aussie intake (common problem) I stopped buying manufactered gaskets for the Aussie 2v intake as they were all to hard and almost always leaked. Go to you local parts house and buy a sheet of good quality gasket material and trace your old gasket to the new material and cut youself out some new ones. Both my son and I have stopped having vaccum intake leads since making our own. BTW it not wise to remove your intake without using a new gasket when re-installing. BTW sometime the vacuum leak is only at idel and when the rpm increases it's pulling enough fuel that it seams fine! Make your own intake gaskets you'll happy you did and have extra money for other things

 

[Anonymous]

Roo, new plugs made no difference. I know I had one bad leak right at the dead cylinder and yes, at speed, the added fuel made it seem to go away.

Ultimately, i need to know if:

- could that bad intake leak yield:
- low compression (120psi vs the 180+ on the others)
- practically 0 firing on that cylinder. Even 120 psi firing would show some difference when the plug wire was pulled

- is there a way to check the ring seal and valve seating in place?


since I think I've settled on pulling the cam, I'll need some guidance there. I know I'll need to remove the radiator, fan, waterpump, timing cover to get access to the gears. I assume I'll need to also remove the grille and support to slide the cam out the front with the motor in place. What else do I need to be mindful of? Should I remove the lifters before or do I just retrieve them from the pan?


Thanks again everyone! Man if it comes down to just a bad intake leak causing all of this, I will be thrilled!

 

[Mustangaroo]

A vaccum leak won't cause low compression, but you can burn a valve running lean, also it may be just a bad ring? You'll have to pull the lifters befoe pulling the cam, and you'll need new lifters to go with your new cam. A blown head gasket could cause low compression in the cyl if that is where the gasket was leaking? Because you say you see nothing wrong, I'd use new intake gaskets and new headgasket and exhaust too and reinstall and check compression etc etc before a complete overhaul! My son pulled his aussie head twice in the same week brfore finding the cracked piston and replacing it!

 

[Anonymous]

This may sound stupid, but what will a burnt valve look like?

The lifters and cam were brand new last year. If the cam is wiped could the lifters be ok? I'll be putting the same cam profile back in.

The headgasket did look to have blown areas around that cylinder. Could the combination of that plus a bad intake leak on the same cylinder yield no bang?

other than pulling the piston(s) to check the rings, is there a way to tell with the piston in place?

 

[addo]

Don't pull the cam yet. Pull the lifters and keep them in order. Buy a solid lifter and borrow/buy a dial rig and cup-ended pushrod. Check that the intake valves are all identical lift, and that the exhaust valves are all the same as each other.

5 thou is the maximum I'd tolerate in diference between lobes. Note that you are not comparing intake to exhaust, but all intakes to each other, etc.

The wall finish needs to be smooth and hone marks clearly visible. The "V" made by intersecting hone marks should be somewhat more than 90° - more like 120°. A too-coarsely honed bore will lightly file your nail, if dragged along it.

This help?

 

[Anonymous]

Superb. Thanks Addo.

 

[mustang6]

In my experience if you've got a chewed up a lobe you will see an obvious sign of it on the bottom of the lifter- instead of a shiny smooth "spin pattern" look with a slightly convex bottom, it will be rough and ground down, flat or concave bottom. If you can see well enough down the lifter holes with the lifters removed, you can also look at the wear pattern on the cam lobes since they are ground at a slight angle to encourage lifter spin. A healthy cam will not show wear past about 33-50% across the lobe. A worn out lobe will show wear across most or all of the lobe.

Measuring lift with a solid lifter as Addo describes is of course the technically correct way to do it though.

 

[Anonymous]

I cleaned up the block top and pistons tonight. Polished them back up nice. Upon inspecting the cylinder walls, the cross hatch, i can still see/ very light pattern but can't really feel it at all. I did notice that the hatch on #2 seems less apparent than the rest. There are much fewer lines in that cylinder wall, if you know what I mean.

What's the best way to pull the lifters out?

 

[wsa111]

Bryce, with a fresh engine with no varnish buildup just use a telescoping magnet to pull the lifters out. I f you have problems pulling a certain lifter you may have to go to a professional lifter puller. The only reason you would have a problem is with a wiped camshaft lobe. but I don't think you will find that problem. If the lifters look like new just put them in the same bore they came out of & bolt the head back on with new intake gaskets.
Keep us informed.
Whats the deal with your transmission???? William

 

[FrankBoss]

If you need I can attempt to lazer cut a intake gasket ...all I would need is a old one(whole gasket) and a little time.

Frank

 

[Anonymous]

Tranny: http://fordsix.com/forum/viewtopic.php?p=171091#171091

whadaya think?