What would cause this ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kcfirstbuild · 06-05-2010, 11:25 PM

I started to pull apart my 307 with 55.000 miles on it. I know that the truck has been sitting for 13 years so i just planed on putting new gaskets in it but then i found trouble.
I pulled of the crank and looked at the cam and it was pitted. What would cause that ??

I also notice on some of the water ports of the head there was some weird stuff in them. I would almost say it looks like solder melted and hardened. Not sure what thats about.

1949gmc · 06-05-2010, 11:37 PM

Pitting or rust on any internal part would probably be caused by condensation inside the engine. Condensation will occur during the warm/cold cycles of our seasons.... especially up by you. Think of it this way: the engine is out in the cold all winter long. The first couple of warm (above freezing) days the engine warms up to ambient temperatures, but the oil remains cold, because it's so thick, thus causing the condensation inside your engine. Same thing happens to your gas tank. I noticed a considerable amount of sweat on the gas tank of my '49 back in March. It had just started to warm up outside, but the gas was still cold. Beyond this explanation, I would have no idea what caused the pitting.

Not sure about the stuff in the water jackets without some pics.

kcfirstbuild · 06-05-2010, 11:44 PM

Could be ?

gkesseru · 06-05-2010, 11:54 PM

The blowby gases get absorbed into the oil; the moisture combines with these impurities to make an acid, which eventually eats away the cam and bearing surfaces. This means that you should never store an engine that has old oil in the crankcase.

hgs_notes · 06-06-2010, 08:31 AM

The weird stuff in the water jacket might be from a stop leak product. The corrosion is likely from what the others have posted. Since the engine will be pulled apart for gaskets any way, just do a rebuild. As long as it doesn't need a ton of machine work the cost is not that bad doing it yourself or with some help from an experienced friend.

I did a shortblock rebuild for about $400 last year, including honing, mag test the block for cracks, dipping the block and polishing the crank journals.

**68jewel** · 06-06-2010, 09:53 AM

Guys have all made various points in which I agree with 100%. Therefore, no need for me to say the same thing. But, I will add this...you now need to rebuild the whole engine and not just swap gaskets.

cdowns · 06-06-2010, 10:12 AM

with the sealer crap in the jacket would scare me// would do nothing less than a hot tank and magnaflux of block and heads to see what you have to start with

at that price i'd in all honesty scrap it and look for a rebuildable 350 core b4 getting that deep into the 307

junkyardjohn · 06-06-2010, 01:43 PM

Quote:

Originally Posted by cdowns

with the sealer crap in the jacket would scare me// would do nothing less than a hot tank and magnaflux of block and heads to see what you have to start with
at that price i'd in all honesty scrap it and look for a rebuildable 350 core b4 getting that deep into the 307

GOOD ADVICE... IT'S CHEAPER TO REBUILD A 350 & YOU GET ALOT MORE OBVIOUS BENIFITS. I LIKE TO HAVE ANY BLOCKS OR HEADS MAGGED BEFORE I DUMP ANY MONEY IN THEM. FOR ME IT'S JUST PEACE OF MIND IF NOTHING ELSE.

JOHN

kcfirstbuild · 06-06-2010, 11:17 PM

I want to keep it a numbers matching truck, so thats why im sticking with the 307. And its not a hot rod so i wont need alot of horses. I had some one check out what that weird stuff was and they said it was metal that didn't get cleaned out from when the heads were cast.

06-05-2010, 11:25 PM	#1
kcfirstbuild Registered User Join Date: Aug 2009 Location: Red Wing Mn Posts: 526	What would cause this ? I started to pull apart my 307 with 55.000 miles on it. I know that the truck has been sitting for 13 years so i just planed on putting new gaskets in it but then i found trouble. I pulled of the crank and looked at the cam and it was pitted. What would cause that ?? I also notice on some of the water ports of the head there was some weird stuff in them. I would almost say it looks like solder melted and hardened. Not sure what thats about.

06-05-2010, 11:37 PM	#2
1949gmc Registered User Join Date: Nov 2004 Location: Lindenhurst, IL Posts: 659	Re: What would cause this ? Pitting or rust on any internal part would probably be caused by condensation inside the engine. Condensation will occur during the warm/cold cycles of our seasons.... especially up by you. Think of it this way: the engine is out in the cold all winter long. The first couple of warm (above freezing) days the engine warms up to ambient temperatures, but the oil remains cold, because it's so thick, thus causing the condensation inside your engine. Same thing happens to your gas tank. I noticed a considerable amount of sweat on the gas tank of my '49 back in March. It had just started to warm up outside, but the gas was still cold. Beyond this explanation, I would have no idea what caused the pitting. Not sure about the stuff in the water jackets without some pics. Last edited by 1949gmc; 06-05-2010 at 11:41 PM.

06-05-2010, 11:44 PM	#3
kcfirstbuild Registered User Join Date: Aug 2009 Location: Red Wing Mn Posts: 526	Re: What would cause this ? Could be ?

06-05-2010, 11:54 PM	#4
gkesseru Registered User Join Date: Dec 2009 Location: California, Maryland Posts: 544	Re: What would cause this ? The blowby gases get absorbed into the oil; the moisture combines with these impurities to make an acid, which eventually eats away the cam and bearing surfaces. This means that you should never store an engine that has old oil in the crankcase. __________________ 72 Fleet (died) 78 Step (sold) 55 Step named Fred (sold) 00 F150 68 Step (named El Scorcho by PO) Build thread for the new El Scorcho http://67-72chevytrucks.com/vboard/s...d.php?t=392932

06-06-2010, 08:31 AM	#5
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,125	Re: What would cause this ? The weird stuff in the water jacket might be from a stop leak product. The corrosion is likely from what the others have posted. Since the engine will be pulled apart for gaskets any way, just do a rebuild. As long as it doesn't need a ton of machine work the cost is not that bad doing it yourself or with some help from an experienced friend. I did a shortblock rebuild for about $400 last year, including honing, mag test the block for cracks, dipping the block and polishing the crank journals. __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

06-06-2010, 09:53 AM	#6
68jewel On the path to financial ruin! Join Date: Jan 2009 Location: Dallas, TX Posts: 722	Re: What would cause this ? Guys have all made various points in which I agree with 100%. Therefore, no need for me to say the same thing. But, I will add this...you now need to rebuild the whole engine and not just swap gaskets. __________________ *'72 Chevelle SS--4.0 Whipple LS7, T56 Magnum, 20X9/20X13 HRE 791R, 6-piston Baer brakes, IRS '68 SWB C10--LS3, TKO-600, 22x10/22x12 HRE 948R, C5 suspension, shockwaves, custom frame Ooh Wee's Makeover*...http://67-72chevytrucks.com/vboard/s...d.php?t=376280

06-06-2010, 10:12 AM	#7
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: What would cause this ? with the sealer crap in the jacket would scare me// would do nothing less than a hot tank and magnaflux of block and heads to see what you have to start with at that price i'd in all honesty scrap it and look for a rebuildable 350 core b4 getting that deep into the 307 __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

06-06-2010, 11:17 PM	#9
kcfirstbuild Registered User Join Date: Aug 2009 Location: Red Wing Mn Posts: 526	Re: What would cause this ? I want to keep it a numbers matching truck, so thats why im sticking with the 307. And its not a hot rod so i wont need alot of horses. I had some one check out what that weird stuff was and they said it was metal that didn't get cleaned out from when the heads were cast.



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