Extreme Sludge, 305 SBC Engine

[Madmax908]

Greetings,

I found this forum while trying to decide how to "clean out" my engine.
I read about many opinions and options, but thought first hand facts/pictures would be more helpful to someone else in my predicament.

The vehicle I have extreme sludge in is a Chevy pickup with a 305 V8, 77k miles.
Previous owner had only driven it about 1500 miles last year, but had 2nd owned it for the last 27 years.
Plenty of signs the vehicle had been maintained at a NAPA shop, but it used about a quart of oil every 500 miles.
There was a slight puff of smoke at start up, not so much at idle, but more under load/acceleration.

The first thing I did was change the oil to SuperTech full synthetic 10w30.
The oil coming out didn't look bad at all, and appeared to have been recently changed.
I drove it around for a while, changed the thermostat to a 180 degree one that worked, and hoped some of the oil consumption would improve over time/use.
It did not.

I began to investigate, and performed a compression test on all the cylinders.
They all were about 160psi, +/- 10 psi, with no jump seen with oil squirted into the cylinders.
This meant the rings were not letting oil blow by, but that the valves and or seals were NG.

I decided the valve seals could be the next logical step, theorizing the seals dried out, or broke.
I took off the valve cover and found this





When I removed the valve cover, there was an accumulation of oil still in the head, as it was trapped in there by the sludge, and couldnt easlily get to the pan.
The sludge was thick and sandy in nature.
When I removed the rocker/pushrods, they barely came out with interference, but were unclogged.
Whatever sludge I disturbed, I just tried to push out of the engine.
The return oil passages needed some help though.

 

[gallydif]

'Kule should be coming thru here soon. Check out LC20. My 350 in the '95 caprice is pretty sludged up as well, not as bad as yours though.
I almost forgot to say...

https://bobistheoilguy.com/forums/ubbthreads.php/topics/4222798/1

 

[Killer223]

interesting, i thought lots of sludge could be a coolant leak. i might be wrong though,
and i've never seen a 305 with under spark plug exhaust manifolds, all the ones i've ever seen were above the plugs and the 350
s were under... again i could be wrong again.
it'll be interesting to see the other thoughts on this one.

 

[Chris142]

Originally Posted By: Killer223
interesting, i thought lots of sludge could be a coolant leak. i might be wrong though,
and i've never seen a 305 with under spark plug exhaust manifolds, all the ones i've ever seen were above the plugs and the 350
s were under... again i could be wrong again.
it'll be interesting to see the other thoughts on this one.
cars had them.over the plugs. Trucks had them below.

 

[Madmax908]

My plan was to remove the rockers one cylinder at a time, clean what I could by scraping and vaccuuming, and re-assemble with new oil seals.
I also planned on flushing the engine with Seafoam.
That was until I read of more on it on BITOG.
It mad sense to slowly clean the engine rather than all at once that would clog the oil pickup.

While telling my tale of woe and about Auto-Rx to my buddy that owns a transmission shop, he told me about the BG109 product.
He pleaded with me to use it and gave me two cans to use.
The logic in his mind was that if I broke the engine by clogging the oil pump with sludge, he would be the one swinging another engine into the truck.

I took the two cans home, warmed up the truck, poured in the BG109, and waited while the truck idled for 10 minutes.
When time was up, I drained the oil. I was a little disappointed in that it was still a cloudy amber color coming out.
I expected a dark brown to black oil to come out. From what my buddy told me, the black sludge granules would be converted back to liquid and suspended in the oil, to be drained out in 10 minutes.
I did take some pictures under the valve cover to compare to the first.




I dont know if I was disappointed or not. There is some sludge removal on the tops of the springs, but not enough for me to say "Wow that $16 mechanic in a can really worked".

I was out of oil, so I went back to WallyWorld for some more oil

 

[askani79705]

PCV valve maybe ? I'd just do short OCIs with a HDEO of your choice and clean it slowly.

 

[Madmax908]

On to my 2nd treatment of BG109.

I filled the truck with WallyWorld SuperTech 10w30 dino, warmed it up, and added the BG.
I was feeling a little bit more daring, so I let it idle for 15 minutes before draining.
Again the oil was still a cloudy amber, and not the black color that would show me its working.

Again I pulled the valve cover to see if it was working.

 

[Madmax908]

Thanks for the welcome.

Quote:
i thought lots of sludge could be a coolant leak

When I investigated the lack of heat, I did notice that the coolant was low by about a half a gallon. I refilled it when I changed the thermostat.

After draining the 2nd dose of BG, I refilled with Rotella 10w30 dino because I read here the diesel oils have more detergents in them.
I drove the truck around the block and the check engine light came on.
The stock gauges are all but useless, but I plan on attaching a mechanical oil gauge tomorrow to be sure.

I have three filters to cut apart tomorrow and I will take some pics.
Hopefully they have some sludge in them to show that the BG is working.

 

[Madmax908]

askani79705, thanks,I changed the pcv during my initial check of the truck, while changing light bulbs, etc. and saw that it was suprisingly clean.

 

[askani79705]

Originally Posted By: Madmax908
askani79705, thanks,I changed the pcv during my initial check of the truck, while changing light bulbs, etc. and saw that it was suprisingly clean.

Did you check the hoses to the pcv ? Might explain why it's clean.

 

[MolaKule]

Holy Sludge, Batman!

Quite frankly I wouldn't have driven it until I had scraped all the sludge from the heads, timing chain, and sump pan and cleaned off the pickup screen.

The BG does appear to have softened up the sludge somewhat.

I would buy a couple of gallons of LC20 from LCD Inc and put it in the oil and pour it over the heads.

I can almost guarantee your hydraulic lifters are so sludged they will have to be replaced.

I would also not be surprised if you had one of more bad bearings as well.

Most likely it suffered a coolant leak and had insufficient cooling and cooked the oil.

 

[Blinker]

Truthfully, i have seen much worse on a SBC and still run fine. I would just stick with short OCI's for awhile if it is running fine. The 305 is a great engine in my experience, a little but underpowered in some applications but very reliable

 

[MolaKule]

Originally Posted By: stower17
Truthfully, i have seen much worse on a SBC and still run fine. I would just stick with short OCI's for awhile if it is running fine. The 305 is a great engine in my experience, a little but underpowered in some applications but very reliable


No doubt it is a tough engine and had one in a van we once owned.

But this is a case of neglect and abuse.

 

[Shannow]

My first car was worse than that (Holden 6 cylinder, same rocker arrangement too). Guy I bought it off had a 7 year old service receipt, and had parked the car permanently 4 months before I got it.

The rocker cover was so full that the rockers had their own grooves in the solid mass.

Scraped what I could, kero in the sump, and idled for 10 mins, drained it like black paint (after I poked a hole in the sludge that was preventing it coming out the drain line).

Threw in a couple of quick changes of cheapo recycled oil (mucho consumption on that), then 20W50 XLD, and the engine was pretty good after that.

Never pulled the sump, never had a lifter problem.

I was 17, unknowing, and lucky.

 

[FlyPenFly]

Strange desire to powerhose it
Off

 

[Lyman]

Im not sure of your skill level but I would tear the heads off and have them gone through. That engine is so simple you might spend 6 or 8 hours doing it from start to finish. And that would be taking your time.

 

[340_Magnum]

You might want to try using conventional Pennzoil 10w-30 (PYB) to slowly clean the engine. Hope you track down any possible gremlins.

 

[DoubleWasp]

I see a completely blocked oil drain back passage. That engine needs serious help.

 

[Silk]

Originally Posted By: Shannow
My first car was worse than that (Holden 6 cylinder, same rocker arrangement too).
The rocker cover was so full that the rockers had their own grooves in the solid mass.


I've seen Holden's so bad that on refilling they'd fill the rocker cover with oil....come back half an hour later, and it still hadn't drained away. They still ran like that. Not my car, all you can do is tell them, and watch them drive away.

 

[SwampSurvivor]

You are going to have to drive it around a bit and let the oil do it's thing. If you're just running it up to temp and draining, that's not going to give the oil enough time to do anything.