305 serious sludge

[Grit dog]

I agree with most of the advice in here, run a synthetic oil and change the filter religiously for a while. Then pop the VC's off in 6mo-a year and see what it did. Synthetics have alot more detergents in them than dinosaur oil does. I *might* consider even adding like a small pour of ATF at the end of each oil change for the last 50-100mi or so. But I definitely wouldn't do anything to try to majorly break it all up quickly. That'll spell disaster.

Yakko, I say the same thing as your dad about automatic transmissions. If you don't know their history, if it's high mileage or if it just hasn't had religious flushes, DO NOT FLUSH an auto trans. It WILL fail shortly after. All I ever do is drop the pan, fresh filter and top it up. Every. Single. Person. I've ever known that had a trans flush done was rebuilding/replacing the trans within 6mo

Agreed on all accounts.
To add, I won’t power flush ANY auto trans. Regardless of condition.
And generally try to stay on top of or do multiple pan dumps to get near all fresh fluid.
If a full fluid replacement is needed then I’ll unhook a cooling line and let the trans pump out the old while adding new. Talking old transmissions with top side dipstick/fillers. Not always possible with newer vehicles.

 

[Matt69olds]

If you do use an additive to the oil to clean out the crud, definitely plan on changing the oil far more frequently than you normally would.

All that crud will more than likely clog the filter.

 

[edgephoto]

If you do use an additive to the oil to clean out the crud, definitely plan on changing the oil far more frequently than you normally would.

All that crud will more than likely clog the filter.

More than likely the pickup screen.

 

[85_squares]

Thanks everyone for your replies & input. I changed the oil again this evening after another 100 miles (changed the rear main seal out as well) and the color is much better, the screen is looking very clear

 

[DoubleDingo]

Thanks everyone for your replies & input. I changed the oil again this evening after another 100 miles (changed the rear main seal out as well) and the color is much better, the screen is looking very clear

NICE!

 

[goldpack]

I'll second Mobil 1.

The other thing that leads to engine gunk is no PCV valve or a broken PCV valve. Make sure you have a functional PCV valve on the engine. Just get a new one to be sure; they're cheap. If the PCV valve's been removed, put it back.

Blow-by of the exhaust gases past the rings is a thing. The PCV valve makes sure those exhaust gasses are pulled out of the crankcase and recycled into the engine. Otherwise they condense into the oil and turn into gunk.

this 1 with a big PLUS.

first thing I buy for a used vehicle is a pcv, As I have pulled some weird things out of vehicles when I have a new OEM in my hand...with zero resemblance to what belongs in there.
and a PCV is spring steel,...it gets old and does not work like it use to ...or gunked up.

2nd pair of things I buy a OEM rad cap and a OEM thermostat)....same thing spring steel. and you can pinch them in your hand and feel what new gets you.
aftermarkets may not flow or open/ close like a OEM or known "good" example.

that said. I have to do a whole lot of reading for this square body, to find good maint. parts cheap.

and for those that are still reading ...Quaker-state = Pennzoil. different labels same company.
I use to run pennzoil in my vehicles years going (thinned out fast,....like dino oil masquerading as full synthetic. )

switched back to mobil 1/ valvoline / wallymart. full syntheics.

 

[Camar068]

Put full synthetic Walmart or Costco oil in for 1000 miles and dump it. Do it again for 2000 miles and dump it. Then put Valvoline Restore and Protect in and change every 3000 miles.

Run Seafoam in the gas tank per their instructions (only gas, not oil). That will clean the carb, valves, and top of piston.

I have done this to bring an engine with +200k miles on it back to running decent. The thing barely ran when I started the process, runs pretty good now. The oil still gets changed every 3000 miles even with the synthetic because it gets dirty pretty quickly due to the crap that built up from the prior owner's neglect.

Here is a video about the Restore and Protect.

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don't be afraid to do the seafoam or other name brands to break down the sludge in the engine. Some manufactures say drive it for a few hundred miles after adding and others say do it in the driveway for a certain amount of time. I've done both versions and they work if you stick with name brands with good internet reviews. Try brand names and follow the directions and you should be better off for sure.

If it's thick sludge, I'd try the ones you do in the driveway before an oil change.

 

[85_squares]

Been cleaning up & solving oil leaks - fixed the rear main, oil pan gasket, oil pressure sensor, and finally got to the intake end rails. Decided to go with the Edelbrock EPS.

I pulled the cast manifold to find nice rock hard substance. Plugged the intake ports, covered the valley & ran the shop vac while I chipped away at it.

Scrapped the cork gaskets in favor of the Right Stuff as usual.

 

[85_squares]

Turned out good, I think. Ended up around 12* of timing (had 14 before with the cast manifold). Doesn't ping or have trouble cranking like it's too advanced.

Blew the idle/gauge fuse at some point so I'm checking wires in those circuits (temp, oil, voltmeter, idle solenoid) to figure that out. I found some wires that were just missing insulation, not pretty.

 

[85_squares]

Figured out the blown fuse this evening.

Actually, had two of them, the previously mentioned idle/gauge & the choke was blown.

Dug around following the Haynes diagrams & found the pink & black wire was missing about an inch of insulation & had grounded out to the block. Fixed that.

Then discovered someone had set the fast idle screw to hold the choke open. Not only that, the electric choke cap was not anywhere close.

Fixed that, too.

I also replaced the throttle cable because the old one was very stiff. Fired it up, thing can seriously move now. Didn't expect the cable to be so responsive and I practically floored it leaving the driveway