914-SHO Motor teardown & inspection

[3d914]

Worked on the left head today. All the exhaust seals were loose on this side also. Intakes were snug, but I could tell the seals had small cracks - so they were dried and on their way out.

I think once I get the heads cleaned up and get the new seals on, I'll bolt up the heads again and do a compression check. With all the exhaust seals gone - that explains why I was getting oil out of the Y-pipe & why all the plugs were black.

If compression is poor then I'll tear down to the pistons. If not, then I think I'll run it again and see how it does.

 

[rubydist]

keep in mind that on top of the valve is that big cap that holds the shim, and it comes down a long ways around the top end of the valve.

my point is that even with no valve seals, these engines don't use that much oil because its hard for the oil to get to the top of the valve in order to leak down.

as long as you are this far into it, make sure you clean up the rings too.

 

[jimtash]

Every SHO engine that I've torn down has one thing in common and that's stuck oil rings and heavy varnish. Especially the longer they've sat around without being ran.

 

[3d914]

Good point guys - and I suspect it will come to that. Another tell was that the back of all the exhaust valves was burnt, and the back of most intake valves had some carbon buildup. So stuff was getting past the valves for sure.

I just want to make sure I have a good reason.

 

[3d914]

Waiting for seals to arrive. Cleaned up the right head, and pulling the engine/tranny off the cradle so the block can be installed on an engine stand.

Burnt out today after an afternoon & evening out with the wife and daughters. Good timing actually since the weather is crappy and cold - don't want to be out in the garage.

 

[3d914]

About all I got done this weekend was to clean up the left head. Got some sinus infection & its been slowing me down. The seals came in, but before I work on those I need to get the engine block up off the floor and onto a stand.

 

[3d914]

Finally pulled the tranny, clutch assy, and flywheel off.

Did notice on the flywheel that the starter teeth don't seem to be engaging fully - only about 1/4 the tooth. I'll have to contact Kennedy to see what they say.

 

[3d914]

Came up with another question I couldn't find in my engine book. Since I plan to pull the oil pan, is it necessary to remove the rear main seal, plate and gasket?

I know the rear seal will likely come loose once I pull the crank out - if I pull the crank out. But the plate and gasket can stay on right?

 

[kevinspann]

You can leave that plate in plate in place when pulling the oil pan. As far as removing the crank and leaving it in place, I'm not sure.

 

[jayro]

Are you just planning on pulling the pistons to replace/clean the rings? If that is what you are doing and I remember correctly from my engine build....you don't have to do anything with the rear main etc since the crank stays in the block. I believe you can just take off the rod caps and push the pistons out the top.

 

[rubydist]

yes, leave the crank and rear seal in place.

pull the rod caps off and push pistons out the top. (they will not fit out the bottom)

 

[Off Road SHO]

Put short pieces of rubber hose over the ends of the rod bolts when removing or replacing the rods to keep from nicking the journals. I guess I also don't need to tell you to squirt a little oil around the top of the pistons so that the rings slide into their grooves in the pistons easily. Don't want to be breaking any lands.

Tom

 

[Lorenr]

I see a lot of statements about cleansing cylinder heads, pistons, rods and related parts. Use the necessary solvents to get the job done and then as a final step, run them through your automatic dishwasher (some may need to do this in the middle of the night when the wife is asleep). Use the caustic dish compound and then complete with the drying cycle. Finally coat everything with ATF.
Done this and it works great.

 

[3d914]

Got some time tonight to pull off the oil pan and start removing/inspecting the pistons.

Here's the low-end all together.

 

[3d914]

Everything came out all right - no hassles. The only pistons that had any hint of stuck rings was #1 and #6 (second pic). All the others looked like #2 (first pic) and the rings were loose. There was no piston pin slop on any of them either - only a little lateral movement - that's it.

Bearings look good on all cylinders.

#1 and #6 had one side of the second ring that was stuck. Otherwise the rings moved freely.

 

[rubydist]

I use STP for assembly ****.

after you get the rings all cleaned up, etc. then put engine oil on them after they are installed in the pistons. wipe the STP in the cylinder bore and around the bearing surfaces before reassembly.

 

[Off Road SHO]

Ditto on the STP for assemble ****, but I would soak those pistons upside down in a tray of acetone (deep enough to cover the wrist pins) to get all that varnish off, and then in a tray of clean oil. Let them drip dry over the tray overnight and then use the STP on the ring area before you put on the ring compressor and slide them back in. The acetone will clean out all the tiny passages that have gotten coked up over the years.

Bearings look brand new.

Tom

 

[intimdatr]

I would add a little ATF to the acetone. It really helps the acetone soak into the carbon. I have a 8 gallon buck with acetone and ATF in it for cleaning gun parts and car parts.

The acetone ATF mixture is what all the silencer people use to clean them. Wicked stuff, makes ANY cut on your hand burn just with the fumes.

 

[3d914]

Per rubydist - in another thread. Wanted it here for reference.
Factory ring gap spec:

Top Ring .012-.018"

2nd Ring .018-.024"

per Ford service manual

 

[3d914]

I was looking at the oil rings more closely and noticed they fit tight and won't rotate around the piston easily. They're not supposed to be as loose as the compression rings are they?

And is there a gap spec for them as well?