Is this normal..? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

IntegratedTJ · 08-17-2013, 11:15 PM

So we pulled off the intake manifold and were greeted by this. Not sure if this is normal or what, but it looked bad to me. This gunk (burnt oil?) is just all over the inside, I'm surprised it even ran like this. What does this indicate? Is this normal?? Thanks in advance.

**Richardwa** · 08-17-2013, 11:17 PM

I have seen way worse than that! Usually caused by lack off oil changes

IntegratedTJ · 08-17-2013, 11:18 PM

Quote:

Originally Posted by Richardwa

I have seen way worse than that! Usually caused by lack off oil changes

Good to hear! Thanks a lot. The truck had been sitting for 8 years in a driveway, so maybe that played a part? Not sure how often the oil was changed before that. Thanks for the quick reply, man. And a good reply to see, too! What a relief!

67_C-30 · 08-17-2013, 11:28 PM

That's the lack of oil changes and the crusty oil that had burned off the choke crossover through the intake. Sadly, I've seen much worse as well. I saw a 305 one time that had the shape of the valve cover molded in in crust around the valves. There was only enough room for the rockers arm to move. It was pouring smoke out of both pipes and pouring oil out both valve cover gaskets because the oil could return and it was running past the valve seals. The guy chipped it all out, sucked it out with a shop vac. The engine stopped smoking and he drove the car for quite a while he was building a new engine with no issues.

Lee H · 08-17-2013, 11:36 PM

This is not normal even though lots of folks have seen worst. This crude gets washed though the oiling system wiping out valve guides, rings, bearings, cranks, and cams.
Posted via Mobile Device

Sammy · 08-17-2013, 11:42 PM

That bad on top imagine what the oil pan looks like inside.

IntegratedTJ · 08-17-2013, 11:45 PM

Quote:

Originally Posted by Sammy

That bad on top imagine what the oil pan looks like inside.

The oil pan is clean as a whistle, actually.

IntegratedTJ · 08-18-2013, 12:05 AM

To add on to this.. Could this contribute to bad compression at all?

**TBONE1964** · 08-18-2013, 12:14 AM

Yes, as others have mentioned, lack of oil changes is the root cause of this and it is a result of what happens when oil gets old and breaks down. It turns to this crust from heat which is why you don't see it in the oil pan. Not as hot down there. It is abrasive and will cut the engines life in half and I am sure if you did a side by side test with a well maintained engine, this one would lack compression also.

Clean it as good as you can and run it. I would be preparing a replacement engine if it was mine.

67_C-30 · 08-18-2013, 12:28 AM

Quote:

Originally Posted by Lee H

This is not normal even though lots of folks have seen worst. This crude gets washed though the oiling system wiping out valve guides, rings, bearings, cranks, and cams.
Posted via Mobile Device

Agreed - It isn't normal - but it is common. A well maintained engine won't do that...

IntegratedTJ · 08-18-2013, 12:33 AM

Quote:

Originally Posted by 67_C-30

Agreed - It isn't normal - but it is common. A well maintained engine won't do that...

I wouldn't let my engine get like this, guys! Like I said it had been sitting for 8 years and I'm just coming of age. It was just like this when I pulled it out!

67_C-30 · 08-18-2013, 12:39 AM

Quote:

Originally Posted by IntegratedTJ

I wouldn't let my engine get like this, guys! Like I said it had been sitting for 8 years and I'm just coming of age. It was just like this when I pulled it out!

Yeah, I figured that was the work of a previous owner. I was just saying that was the reason it did it. If you clean it up and keep it changed from here on out, it will probably last you a while.

IntegratedTJ · 08-18-2013, 12:58 AM

Quote:

Originally Posted by 67_C-30

Yeah, I figured that was the work of a previous owner. I was just saying that was the reason it did it. If you clean it up and keep it changed from here on out, it will probably last you a while.

Good to know. I plan on running a full rebuild kit, cleaning the hell out of it, replacing anything that needs replacing. So this problem should be like it was never there. Appreciate all the replies.

**TBONE1964** · 08-18-2013, 09:50 AM

Quote:

Originally Posted by IntegratedTJ

Good to know. I plan on running a full rebuild kit, cleaning the hell out of it, replacing anything that needs replacing. So this problem should be like it was never there. Appreciate all the replies.

You stated that is was weak on compression, yes? For that reason if you are going to rebuild it, I would do it .030 over and be assured that the piston to wall clearance is good. You will have piece of mind knowing that if well maintained, you will get 100K plus out of the rebuild. Also takes care of the compression and makes for a more efficient running engine.

Just my thoughts

Flint70step · 08-18-2013, 11:51 AM

If you do a rebuild use that block.The vertical rectangular casting bars in the intake valley just below the intake ports indicate that you have a nice high nickle content block.A good foundation for a rebuild

08-17-2013, 11:15 PM	#1
IntegratedTJ Registered User Join Date: Jul 2013 Location: Vallejo, California Posts: 71	Is this normal..? So we pulled off the intake manifold and were greeted by this. Not sure if this is normal or what, but it looked bad to me. This gunk (burnt oil?) is just all over the inside, I'm surprised it even ran like this. What does this indicate? Is this normal?? Thanks in advance.

08-17-2013, 11:17 PM	#2
Richardwa Active Member Join Date: Sep 2011 Location: Selah Wa Posts: 153	Re: Is this normal..? I have seen way worse than that! Usually caused by lack off oil changes

08-17-2013, 11:28 PM	#4
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: Is this normal..? That's the lack of oil changes and the crusty oil that had burned off the choke crossover through the intake. Sadly, I've seen much worse as well. I saw a 305 one time that had the shape of the valve cover molded in in crust around the valves. There was only enough room for the rockers arm to move. It was pouring smoke out of both pipes and pouring oil out both valve cover gaskets because the oil could return and it was running past the valve seals. The guy chipped it all out, sucked it out with a shop vac. The engine stopped smoking and he drove the car for quite a while he was building a new engine with no issues. __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club!

08-17-2013, 11:36 PM	#5
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,147	Re: Is this normal..? This is not normal even though lots of folks have seen worst. This crude gets washed though the oiling system wiping out valve guides, rings, bearings, cranks, and cams. Posted via Mobile Device __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

08-17-2013, 11:42 PM	#6
Sammy Registered User Join Date: Apr 2000 Location: Bonne Terre, Mo Posts: 3,005	Re: Is this normal..? That bad on top imagine what the oil pan looks like inside. __________________ '69 Chevy Long Fleet & '71 GMC Short Step & Project "ODD BALL" "You can wash a pig, soak it in most expensive perfume. In the end it is still just a pig." ODD BALL build thread http://67-72chevytrucks.com/vboard/s...d.php?t=478629"

08-18-2013, 12:05 AM	#8
IntegratedTJ Registered User Join Date: Jul 2013 Location: Vallejo, California Posts: 71	Re: Is this normal..? To add on to this.. Could this contribute to bad compression at all?

08-18-2013, 12:14 AM	#9
TBONE1964 Cluster King Join Date: Nov 2012 Location: Junction City, OR Posts: 5,263	Re: Is this normal..? Yes, as others have mentioned, lack of oil changes is the root cause of this and it is a result of what happens when oil gets old and breaks down. It turns to this crust from heat which is why you don't see it in the oil pan. Not as hot down there. It is abrasive and will cut the engines life in half and I am sure if you did a side by side test with a well maintained engine, this one would lack compression also. Clean it as good as you can and run it. I would be preparing a replacement engine if it was mine.

08-18-2013, 11:51 AM	#15
Flint70step Registered User Join Date: Jan 2011 Location: Lake Travis,Texas Posts: 586	Re: Is this normal..? If you do a rebuild use that block.The vertical rectangular casting bars in the intake valley just below the intake ports indicate that you have a nice high nickle content block.A good foundation for a rebuild __________________ 72 Cheyenne Super LWB 350/350 Factory A/C Tilt/Posi White/Med Red/White(on the way) 72 Custom Deluxe Burb(Arizona truck)Nice interior Great patina Project Patina Azul http://67-72chevytrucks.com/vboard/s...d.php?t=467668



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