fillled both sides of the valve with alcohol and both sides held it for over 5 min with no leaks
One white valve
- Thread starter Robliepse
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RonnieLongball
Well-Known Member
the water jacket appears to be casting flash in that picture. But obviously no way to tell from the picture. I agree with you that your best bet in this situation would be to reassemble and test. Had many radiators come in the shop that would hold 15psi cold, but as soon as they had heat in them wouldn’t hold pressure. I wouldn’t rule that out in the head either.
PlymouthMakesIt
Active Member
Is that a head made before or after 1974, when they switched to unleaded gas? The old heads don't have hardened seats as they depended on the lead in the gas to cushion and protect them. If you have an old head and are burning unleaded pump gas you could have cracked the valve seat.
CHGRSE74
Well-Known Member
I just quickly read this series of posts…I dident see any mention of magna fluxing the components. Find a reputable machine shop. If there is a crack you will know immediately if not sooner. It is definitely antifreeze that is burning. Did you smell the exh, you will know the smell of burning coolant.
thanks for all the insights and advice.
~ The valves and valve seats were updated when the engine was rebuilt during the build, I also tested the valves with some alcohol, The "white valve" held the alcohol for several hours with no leakage.
~ I plan to upgrade to some different heads once I determine the real issue (if possible).
~ I'm 100% confident that the car wouldn't start smoking until the cooling started to pressurize and it would get worst under load.
~ Already talking to the machine shop that did the original work on the block and heads. Trying to avoid pulling and disassembling the short block if possible. They want me to bring them the head so they can rule that out before we go to the next step.
~ The car wasn't raced or abused and it has less than a mile of use after it started smoking.
~ Question, which I think I know the answer, do I need to use a new head gasket and head bolts for the initial cooling pressure test or can I use copper spray on my original suspect gasket? Not planning to start the car,
Thanks again for all the advice and insights
~ The valves and valve seats were updated when the engine was rebuilt during the build, I also tested the valves with some alcohol, The "white valve" held the alcohol for several hours with no leakage.
~ I plan to upgrade to some different heads once I determine the real issue (if possible).
~ I'm 100% confident that the car wouldn't start smoking until the cooling started to pressurize and it would get worst under load.
~ Already talking to the machine shop that did the original work on the block and heads. Trying to avoid pulling and disassembling the short block if possible. They want me to bring them the head so they can rule that out before we go to the next step.
~ The car wasn't raced or abused and it has less than a mile of use after it started smoking.
~ Question, which I think I know the answer, do I need to use a new head gasket and head bolts for the initial cooling pressure test or can I use copper spray on my original suspect gasket? Not planning to start the car,
Thanks again for all the advice and insights
I did a dye chem test (Cantesco) on the head and cylinder and didn't see anything
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Possible bad head gasket. Check the block and head with a good straight edge. Probably it's good just being machined recently. Use a good quality gasket. Torque it properly then loosen and Torque again. You'll get a little more out of it the second time around.
Good luck!
Did you check the valve guide and bowl area on the white valve? Is the valve white on the backside also?
Good luck!
Did you check the valve guide and bowl area on the white valve? Is the valve white on the backside also?
white on both sides
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Is the valve stem seal still there? Might look at the other exhaust valves to see if they were used. Some only use them on the intake.
Just saw you took it to the machine shop
68_661charger
Well-Known Member
Unless I missed something, I dont see any dowel pins in the block to head. I had a coolant leak from that area from the head not sitting down completely so maybe if they are missing its causing a problem?
I’ll take a look, engine has been running for 5+ years with no issues. Thanks for the insight.
Update and a couple of questions for the smart kids in the room.
The head passed the mag pen and pressure testing at the machine shop and they couldn't find any issues. This leaves to either simply a bad head gasket or a block issue. My plan is to reinstall the head and pressurize the cooling system. (should have done this before removing the head). At this time I'm not planning on totally reassembling and starting the engine.
If I'm only pressure testing the cooling system can I use the original head bolts if I don't plan on starting the engine? Will a new gasket and original bolts work for this head gasket cooling pressure test? My other thought is to use new bolts and if it passes the pressure test move forward with reinstalling the exhaust and ignition, starting the car to see if it still smokes. The stock manifold and plugs are a pain in the a&#^ .
Once I find the root cause of the smoke I plan on upgrading the heads and adding headers to get more out her.
The head passed the mag pen and pressure testing at the machine shop and they couldn't find any issues. This leaves to either simply a bad head gasket or a block issue. My plan is to reinstall the head and pressurize the cooling system. (should have done this before removing the head). At this time I'm not planning on totally reassembling and starting the engine.
If I'm only pressure testing the cooling system can I use the original head bolts if I don't plan on starting the engine? Will a new gasket and original bolts work for this head gasket cooling pressure test? My other thought is to use new bolts and if it passes the pressure test move forward with reinstalling the exhaust and ignition, starting the car to see if it still smokes. The stock manifold and plugs are a pain in the a&#^ .
Once I find the root cause of the smoke I plan on upgrading the heads and adding headers to get more out her.
Forgotten whether you put a straight edge to block deck surface, I'd do that if you didn't. Put Hi Tack on your new gasket, clean bolt hole there are tools for that but a bottom works. You don't want false torque readings. I'm there are suggestions.
Thanks, the machine shop checked the head and I need to check the block
thanks for the feedback on the dowel pins. I do have one on the rear of the block but the front is missing. However it doesnt appear to be part of the cooling jacket on the block or head. do you think it could still be contributing? If so, where can I get a new one?
A parts store or a machine shop may have them. Amazon Granger McMaster Car.
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