Advice wanted on de-gunking intake and combustion chambers

[thehackmechanic]

I'm not a guy who slides easily down a slippery slope, but...

I bought this '72tii last spring from a guy who said it sat for nearly ten years. It drives and runs fine, doesn't seem to burn oil even when nailed and lifted, but it had a persistent lean running issue that caused me to pull the intake manifold off to change the gaskets and check for leaks. Of course, I found none, but...

There's a lot of carbon on the intake bases (that the bottoms of the plastic plenums attach to). There was also a fair amount in the throttle body. There is some, but not nearly as much, in the big part of the intake manifold that the tops of the plenums attach to. Looking in at the intake valves, I expected carbonized horror, but they look pretty good.

However:

--The entire valve train is deep brown with varnish.

--Using a small inspection scope and looking into the spark plug holes, there's a fair amount of carbon on the piston crowns.

--I had posted last fall that the car had surprisingly high leakdown numbers, like 40%.

A part of me wants to just finish cleaning the intake and put it back together, but part of me things, well, intake's off, I could have the head off in an evening, could thoroughly clean the combustion chambers and the piston crowns. I could prophylactically replace the head gasket (I am very mindful of the fact that Wegweiser's F-Bomb blew its HG at The Vintage last year). With the head off, hell, I could drop the pan and pop the pistons out and re-ring them...

No, stop, stop, stop. Dig those crampons and ice axe into that slippery slope.

Just put it back together and drive it, right?

[c.d.iesel]

google : " walnut blasting "

[nbristow01]

If it was running decent, not smoking and made decent power I would put it back together and just drive it. I imagine it will last many more years.

If the engine numbers do not match the VIN then source a decent used block...build a short block, put it on standby and do a swap when the timing is better

[jgerock]

This is the FUN part of owning a tii!

I scrubbed my intake manifold bits with a solution of Purple Power and water. The PP contains lye and will make your skin peel - so wear rubber gloves.

After some scrubbing, I ran the pieces thru the dishwasher (ala BLUNT), but I feel it didn't work like I wanted it to..

Best method for me was soaking all the parts repeatedly, then scrubbing with Red Scotch brite pads.

After cleaning, use Eastwood's PRE cleaner spray and rags, then Self-etching primer and Aluma-Blast paint (should add clear coat but I didn't). Note that I did not bead blast any parts. The throttle body and base intake section were left as-cast (not painted).

Before (as purchased)

During teardown

After much work

[c.d.iesel]

from the INJECTORs ~ to ~ the ~ piston tops :

a full bottle of TECHRON added to 1-Full Tank Gas,

then -=D R I V E ! for 250 miles non-stop==-

[thehackmechanic]

c.d., thanks. I'd forgotten about Techron.

Jim, NOTHING I own is, or ever will be, that clean.

[vinceinIL]

I'd agree with Creighton, get it all tuned to specs, add Techron or Seafoam, then take it for a nice long drive on a clear day to get the engine up to temperature for a long period of time. Then take compression and leakdown tests and see how they look. Also check the oil level and color before and after you take the trip.

vince

[wegweiser]

Find a baby seal.

While standing, hold baby seal against your chest as tightly as you can - squeezing firmly just below the front flippers.

Have a neighborhood kid hold a dixie cup under the seal to catch whatever drips out.

Use that stuff.

Note: The more adorable the seal - the better the results.

Dilute with 3 parts tap water. Repeating as necessary.

Or use carb cleaner in aerosol cans and some dental picks / wire brushes.

FYI: I chose to media blast mine on the F Bomb - thoroughly cleaning and rinsing with water / compressed air afterward.

[Napes]

To add to what Paul said ("Or use carb cleaner in aerosol cans and some dental picks / wire brushes") stiff, short-bristle Paste Flux Brushes also work well. Readily available at Home Depot, etc.

Bob Napier

[saaron]

I would keep the original carbon. Who says patina can only be on the outside? That is original carbon. You should keep it.

Seriously, I would think driving it for some long distances with the Techron could make a dent. Do that to Vintage and back, and see how it looks afterwards.

Then again, the weather is cold and gross, so you kind of have the time to fall down the slope then crawl back up.

Scott

PS I am hard pressed to see anything recognizable from my car in Jim G's car. It is possible some of the parts are the same (maybe). It's from a different planet than mine.

[layers]

Hi--

My grandfather, who departed our world decades ago, suggested an occasional cleaning by slowly pouring a full glass of water into the top of the carb then driving a couple of hundred miles.

While he was not a professional mechanic, he cared for his cars (and tractors-- he was born on a dairy farm 100 miles East of St. Louis) from the time he earned a Certificate of Automotive repair in 1913 (he was 12) until the mid 1960's.

I have not tried this on tii, but I bet you could connect your windshield washer tubing to an intake manifold vacuum port and get water injection!

Well anyway, good luck!

[mrgesq]

Sea Foam has saved more than one tear down in my family. Add a quart to the oil and take it for a 30 minute drive. Drain and see the crap that comes out. I like techron too, but seafoam in the gas does roughly the same thing. Have you watched some of the videos on youtube when people "SeaFoam" their cars? The smoke is nuts. They even invented the curved injection tube so you can snake it around the throttle body gasket in newer cars. My 76 sat for over ten years in storage. When started, it banged like crazy. One pint of Seafoam in the oil and after about 1/2 hour it all loosened up and quieted down. That was 7 years ago and it runs great.

BTW, looking forward to my signed copy of the new book.

[jimk]

Using the "right stuff" at 27,000mi. It aint Seafoam, it aint Techron.

[thehackmechanic]

Jim, are you talking about Auto-Rx?

I had Marvel Mystery Oil sitting in the pistons for several months while the car was down. I removed, scrubbed, and reassembled the TB and intake plenums, and dumped Techron in the tank. I got the car started back up this weekend. It runs well, no obvious smoke. I'm going to follow c.d.'s advice and do the least invasive thing first -- drive it for a few hundred miles like that. But that'll only clean out what's in the fuel path. The inside of the head is completely brown with varnish and gum. On the one hand that's just cosmetic, but on the other hand, that varnish is probably everywhere. I'm generally hesitant use oil additives because of the snake oil reputation, but I did stumble upon Auto-Rx when working on a friend's Passat because of its reputation for de-sludging. I'm just afraid of damaging anything in the KFish pump.

[Bill_Riblett]

Rob,

I haven't been following this thread so maybe you have already considered this.

When you were looking for air leaks, did you check the boot over the bottom of the throttle body? Look up p/n 13 54 1 258 015.

If this boot is cracked or missing it can cause big air leaks.