HELP Update (valve & intake gaskets, carbon buildup)

brrian

Greasemonkey
Jul 7, 2022
103
28
Pittsburgh, PA
3.8L V6. I'm replacing my carb with a rebuilt one. The valve covers were leaking & the bolts were so loose that I could turn them by hand. The intake bolts weren't much tighter, and the top of the engine was an oily, grimy mess. The intake is off & the ports are caked with carbon - see below. Note the area in the center... it seems like there might be an entire passage plugged on one or both heads. See images below with comparisons to heads I found online. What are those passages? Note that the car ran a little rough at startup but once it warmed up it seemed to run fine.


driver.jpg


passenger.jpg
 
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78Delta88

Master Mechanic
Supporting Member
May 23, 2022
381
43
SW Arizona
3.8L V6. I'm replacing my carb with a rebuilt one. The valve covers were leaking & the bolts were so loose that I could turn them by hand. The intake bolts weren't much tighter, and the top of the engine was an oily, grimy mess. The intake is off & the ports are caked with carbon - see below. Note the area in the center... it seems like there might be an entire passage plugged on one or both heads. See images below with comparisons to heads I found online. What are those passages? Note that the car ran a little rough at startup but once it warmed up it seemed to run fine.


View attachment 206494

View attachment 206495
The sooty oily deposits are consistent with exhaust crossover.

Just soak heads in solvent and clean with wire brush.
 

airboatgreg

Comic Book Super Hero
Oct 2, 2016
2,747
113
If you are not taking the heads off cover inside of engine and chip the carbon out to clean the ports. Clean everything up, start the engine for a few minutes and change oil. Go to an AC Delco dealer and buy 2 cans of X66A and follow directions as you spray it through the carb with the engine running. I would also put a bottle of Techron in the tank. BG sells a great 3 part additive also
 
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brrian

Greasemonkey
Thread starter
Jul 7, 2022
103
28
Pittsburgh, PA
I left the intake gasket (pan) in place, plugged the open ends & all open ports, then surgically removed the carbon. I vacuumed as I removed it & once I was done I blew everything out of all ports. then I removed the intake gasket and found what I think was fine steel wool wrapped around two pushrods. Must have been left in there by the hack that worked on this engine. I plugged all openings again, surgically removed that & carefully cleaned the valley.

I cleaned & painted the intake, valve covers & some other small parts & I'm getting ready to put it back together.

I was going to just go with cork gaskets but I think I'm going to try these Fel-Pro PermaDryPlus gaskets.

I'll take your advice on the oil change & X66A. Thanks!

IMG_20220910_144605.jpg
 
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Reactions: 1 user

78Delta88

Master Mechanic
Supporting Member
May 23, 2022
381
43
SW Arizona
I left the intake gasket (pan) in place, plugged the open ends & all open ports, then surgically removed the carbon. I vacuumed as I removed it & once I was done I blew everything out of all ports. then I removed the intake gasket and found what I think was fine steel wool wrapped around two pushrods. Must have been left in there by the hack that worked on this engine. I plugged all openings again, surgically removed that & carefully cleaned the valley.

I cleaned & painted the intake, valve covers & some other small parts & I'm getting ready to put it back together.

I was going to just go with cork gaskets but I think I'm going to try these Fel-Pro PermaDryPlus gaskets.

I'll take your advice on the oil change & X66A. Thanks!

View attachment 206569
I think you will like the Perma Dry better.

Cork is fine, but if this is first time doing stuff like this, cork is very easy to over torque and then you get leaks.
 

78Delta88

Master Mechanic
Supporting Member
May 23, 2022
381
43
SW Arizona
... I removed the intake gasket and found what I think was fine steel wool wrapped around two pushrods....

Yeah that's a big ???

I've had rats, mice, millipeads, centipeads, wasps, yellow jackets, ants, dust, dirt, tools, parts of tools, nuts and bolts... Never steel wool.
 

brrian

Greasemonkey
Thread starter
Jul 7, 2022
103
28
Pittsburgh, PA
Sunday run day! I put the last parts back on this morning - including everything that had been plugged, disconnected or found not to work.

The good:

It started right up! It seems to idle better than it did before I tore it apart. I haven't driven it yet.

The bad:

The freaking thermostat housing is leaking. When I put it back on I didn't feel great about it sealing but I just went with it. So, I have to deal with that.

It's a bit rough when you give it gas. I'm kind of unsure as to why but to start I plan to check for vacuum leaks. I'm pretty sure I didn't leave anything open but some of the hoses & connections were a little questionable. The carb is new (rebuilt), was correct for and set up for my engine, so I don't suspect it but can't rule it out.

---

I need to check timing, just to know what it's set at. It seems okay.

It's not done yet, but I'm happy that it's running, and proud at what I was able to do. I fixed a broken smog pump, corrected the emissions system, replaced intake & valve cover gaskets, replaced a bunch of small parts & made it all look good. All in my backyard & no prior experience.
 
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brrian

Greasemonkey
Thread starter
Jul 7, 2022
103
28
Pittsburgh, PA
Thermostat fixed... I replaced the crappy steel one with a new cast aluminum one. No coolant or oil leaks! Tomorrow I'll check timing, vacuum & might smoke test.
 

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