Rebuilding engine

[Motoman991]

Have any of you guys taken the engine apart while it was in the car?
Because I am going to need to take apart the back side of the engine because a piston ring came apart in the back outter left cylinder.
I am just wondering if it would be possible to take apart the back side of the engine in the car, I already have taken off everything for the intake.
I thought these v8's were suppose to last a while? I haven't driven mine all that hard and it has 113k on it.

 

[Mr Anonymous]

Possible? Yes.

Desireable? No freakin' way.

Putting aside the difficulty of getting access to everything you need to in order to R&R the rear head, re-timing the motor in the car and getting the timing cover sealed properly can be very difficult and time-consuming, especially if you haven't done it before.

Best of luck!

 

[Racer X]

A piston ring came apart? Is that even possible?

Before you dig too deep into this, may I ask, what are the symptoms you're experiencing with the car? The V8 has a very well known, and very well documented design flaw with the camshaft assembly.

 

[V6&V8SHO]

I got to see the rebuilding process. Beer is the first purchase.

 

[Motoman991]

The spark plug in the cylinder looks like something was beating it from the inside. There are some deep scratches in it and the metal thing is almost touching the electrode. The compression on that cylinder is at 150psi when the other 3 cylinders on that bank are around 220psi. I took some oil and squirted it down into low compression cylinder and took some more readings. It went from 150 to 175, Then i took another reading and it went up to 200, then back down to 175. This is why I am thinking something happened to the piston rings.

 

[Mr Anonymous]

The spark plug in the cylinder looks like something was beating it from the inside. There are some deep scratches in it and the metal thing is almost touching the electrode. The compression on that cylinder is at 150psi when the other 3 cylinders on that bank are around 220psi. I took some oil and squirted it down into low compression cylinder and took some more readings. It went from 150 to 175, Then i took another reading and it went up to 200, then back down to 175. This is why I am thinking something happened to the piston rings.

More likely, you've got piston material floating around in there -- probably a ring landing if you still get decent compression with oil. Are you running any kind of tuning? We've seen 4 cars now with tuning that have melted pistons in cylinder 1 or 5 due to a way way way overly lean mixture. If the spark plug is damaged, whatever is floating around in there has probably damaged the head beyond repair.

Also, who welded your cams and how long ago? It's also possible that a piece of foreign material found its way into the cylinder during the welding process.

 

[Motoman991]

I am not running any type of tuning.
The cams were tig welded about 3 months ago by a welding shop near me. The welds look to be pretty good too.

 

[Racer X]

I'm wondering if the welds weren't done right, and the sprocket slipped anyway.

I forget who's car it was, but it has happened one time that I know of.

 

[Motoman991]

I'm wondering if the welds weren't done right, and the sprocket slipped anyway.

I forget who's car it was, but it has happened one time that I know of.

If that happened I thought that it would mess up all four cylinders and not just one.

 

[NebraskaSHO]

Depends if the piston was coming up and then bent the valves in that cylinder, and made the motor quit resulting in only one cylinder bent.

Like this one:
http://cgi.ebay.com/ebaymotors/96-9...emQQcategoryZ33617QQihZ011QQitemZ320033003645

Just an idea.

 

[JSIL1]

Seeing as you are going to pull the heads off. Why not get them both machined to accept the bigger Duratec valves?

 

[Motoman991]

Seeing as you are going to pull the heads off. Why not get them both machined to accept the bigger Duratec valves?

I might do that if I have money.

 

[SuperHO]

It almost sounds like you may have simply dropped a valve.......just my thoughts....

 

[Mr Anonymous]

It almost sounds like you may have simply dropped a valve.......just my thoughts....

He's still able to get compression, a dropped valve wouldn't hold any compression whatsoever.

 

[SuperHO]

good point!