Read my head and valves - The 1947 - Present Chevrolet & GMC Truck Message Board Network

vtwinsport · 11-13-2010, 01:20 PM

Hey all,
What does this set of heads tell you about the combustion?

Malo83 · 11-13-2010, 02:09 PM

That white area in the CC an indication of a leaky head gasket ?

cableguy0 · 11-13-2010, 02:34 PM

Any pictures of the gasket itself? It looks like you were running lean.

vtwinsport · 11-13-2010, 02:38 PM

none of the gasket. didn't have any oil in the anti freeze when I changed it at the same time. I was told my valve guides are worn out on #5 & 6

Restrorob · 11-13-2010, 05:19 PM

Quote:

Originally Posted by cableguy0

It looks like you were running lean.

I agree with cableguy..... A quick smack on the valve spring with a deep socket will pop the keepers out so you can remove the spring, Then see if the valve wiggles in the guide. It seems odd that only those two guides would be worn.....

**PRattenbury** · 11-13-2010, 07:02 PM

Yeah, either lean condition or burning antifreeze.

vtwinsport · 11-14-2010, 01:08 PM

Yes, that's what I kept thinking so I put a new head gasket on when these went back in. I did do a valve movement test when the heads were out. There was very very small movement. I didn't have a dial indicator to measure the side to side play in the guide so I put them back in because a vacuum test before they came out didn't show any indication of sticky valves or valves leaking.
The # 5&6 plugs are still being ash fouled just like before the new head gasket when on so I'm thinking the valve guides are worn and or the heads are cracked.
I guess I'll pull them and take them to a block shop for inspection.
thx all

**PRattenbury** · 11-14-2010, 02:00 PM

Did you make totally sure you don't have a vacuum leak anywhere, and fattening up the mixture??? It's really common to get vacuum leaks at the intake and carb gaskets.

vtwinsport · 11-14-2010, 03:18 PM

Yes, I sprayed carb cleaner all around the intake, carb, brake booster and vacuum lines. I didn't get any change in idle when I did this. The exhaust valves do look like they've been running lean as they're so white.
I'm not sure what else to check so I think taking the heads to the block shop is the next step. The mystery though is if I am burning coolant in 5 & 6, why there is no coolant slick in my oil.
Thanks for the comments

**PRattenbury** · 11-14-2010, 05:41 PM

It's possible to have a failure that allows coolant into the combustion chamber and not the crank case. It just looks like all cylinders were running lean to some degree.

vtwinsport · 11-15-2010, 10:27 AM

I am not sure what would be making all the cylinders run lean. I adjusted the idle screws to maximum vacuum and then in (rich) a 1/2 turn. Timing is at 10 degrees and it seems to run great at all these settings.

Well, pulling the heads this time will tell me if all cylinders are running lean still.
thanks for the feedback.

**PRattenbury** · 11-15-2010, 02:10 PM

Turning the screws in is not rich. That would be lean. Backing the screws out makes the mixture richer. If you turn the screws all the way in you will shut all the gas off and the engine will die. Give it a try.

vtwinsport · 11-15-2010, 09:19 PM

oops, that doesn't help making it lean. thx.
Machine shop told me the exhaust valve seats were cracked and that there is a hairline crack at 5 & 6 causing the coolant leak at these locations. I guess this is common on older heads because the exhaust valves on 3 & 5 and 4 & 6 are side by side and they really cook right there.
Time to upgrade to aluminum heads.
Thanks all.

11-13-2010, 01:20 PM	#1
vtwinsport Registered User Join Date: Nov 2008 Location: edmonton, alberta Posts: 293	Read my head and valves Hey all, What does this set of heads tell you about the combustion? Attached Images __________________ 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/

11-13-2010, 02:09 PM	#2
Malo83 Cruzzzn' Vet Join Date: Jan 2005 Location: Porterville,Ca. Posts: 1,918	Re: Read my head and valves That white area in the CC an indication of a leaky head gasket ?

11-13-2010, 02:34 PM	#3
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	Re: Read my head and valves Any pictures of the gasket itself? It looks like you were running lean. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

11-13-2010, 02:38 PM	#4
vtwinsport Registered User Join Date: Nov 2008 Location: edmonton, alberta Posts: 293	Re: Read my head and valves none of the gasket. didn't have any oil in the anti freeze when I changed it at the same time. I was told my valve guides are worn out on #5 & 6 __________________ 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/

11-13-2010, 07:02 PM	#6
PRattenbury Senior Member Join Date: Feb 2010 Location: Maumelle, AR Posts: 478	Re: Read my head and valves Yeah, either lean condition or burning antifreeze.

11-14-2010, 01:08 PM	#7
vtwinsport Registered User Join Date: Nov 2008 Location: edmonton, alberta Posts: 293	Re: Read my head and valves Yes, that's what I kept thinking so I put a new head gasket on when these went back in. I did do a valve movement test when the heads were out. There was very very small movement. I didn't have a dial indicator to measure the side to side play in the guide so I put them back in because a vacuum test before they came out didn't show any indication of sticky valves or valves leaking. The # 5&6 plugs are still being ash fouled just like before the new head gasket when on so I'm thinking the valve guides are worn and or the heads are cracked. I guess I'll pull them and take them to a block shop for inspection. thx all __________________ 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/

11-14-2010, 02:00 PM	#8
PRattenbury Senior Member Join Date: Feb 2010 Location: Maumelle, AR Posts: 478	Re: Read my head and valves Did you make totally sure you don't have a vacuum leak anywhere, and fattening up the mixture??? It's really common to get vacuum leaks at the intake and carb gaskets.

11-14-2010, 03:18 PM	#9
vtwinsport Registered User Join Date: Nov 2008 Location: edmonton, alberta Posts: 293	Re: Read my head and valves Yes, I sprayed carb cleaner all around the intake, carb, brake booster and vacuum lines. I didn't get any change in idle when I did this. The exhaust valves do look like they've been running lean as they're so white. I'm not sure what else to check so I think taking the heads to the block shop is the next step. The mystery though is if I am burning coolant in 5 & 6, why there is no coolant slick in my oil. Thanks for the comments __________________ 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/

11-14-2010, 05:41 PM	#10
PRattenbury Senior Member Join Date: Feb 2010 Location: Maumelle, AR Posts: 478	Re: Read my head and valves It's possible to have a failure that allows coolant into the combustion chamber and not the crank case. It just looks like all cylinders were running lean to some degree.

11-15-2010, 10:27 AM	#11
vtwinsport Registered User Join Date: Nov 2008 Location: edmonton, alberta Posts: 293	Re: Read my head and valves I am not sure what would be making all the cylinders run lean. I adjusted the idle screws to maximum vacuum and then in (rich) a 1/2 turn. Timing is at 10 degrees and it seems to run great at all these settings. Well, pulling the heads this time will tell me if all cylinders are running lean still. thanks for the feedback. __________________ 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/

11-15-2010, 02:10 PM	#12
PRattenbury Senior Member Join Date: Feb 2010 Location: Maumelle, AR Posts: 478	Re: Read my head and valves Turning the screws in is not rich. That would be lean. Backing the screws out makes the mixture richer. If you turn the screws all the way in you will shut all the gas off and the engine will die. Give it a try.

11-15-2010, 09:19 PM	#13
vtwinsport Registered User Join Date: Nov 2008 Location: edmonton, alberta Posts: 293	Re: Read my head and valves oops, that doesn't help making it lean. thx. Machine shop told me the exhaust valve seats were cracked and that there is a hairline crack at 5 & 6 causing the coolant leak at these locations. I guess this is common on older heads because the exhaust valves on 3 & 5 and 4 & 6 are side by side and they really cook right there. Time to upgrade to aluminum heads. Thanks all. __________________ 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/ Last edited by vtwinsport; 11-15-2010 at 09:21 PM.



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