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#1 |
Pronounced "Pew-al-up"
Join Date: Oct 2002
Location: Puyallup, Washington
Posts: 845
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I have a question for you motor guys who have been giving me a hand through my project.Today I started replacing my valve seals with the umbrella type. I have the engine on a stand, and the heads are still on the block.
When I pressurize the cylinder to hold the valve up so I can remove the spring I am getting alot of blow by from where the valve seats. On a couple of the cylinders it has been bad enough to make my compressor (5 gal) cycle constantly.On one cylinder in particular I could not hold sufficient pressure to force the valve to stay up! I am contemplatin pulling the heads and lapping in some new valves. What do you think? Should I just remove the heads and replace the valves? Should I have the heads machined, if so what kind of cost am I looking at? I did not plan on going through the lower end, and am also wondering what to expect if the heads are done and not the lower end what may happen to the rings? Any help would be greatly appreciated as usual!!! ![]()
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Classic GM Trucks of Washington Club Member 1970 FS chevy,350/350, Edelbrock cam and intake. Holley 650 carb,HEI,AT,Tangier Orange, 18's, Power Locks, Truck Photos |
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#2 |
Account Suspended
Join Date: Nov 2003
Location: Fort Worth, Texas
Posts: 0
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I think you already know the answer.......
If the seats are that bad, yes, you need a valve job. |
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#3 |
Account Suspended
Join Date: Jan 2000
Location: Woodstock, IL
Posts: 7,020
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And guides!
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#4 |
Senior Member
Join Date: Jul 2001
Location: Muskegon,MI,USA
Posts: 6,026
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Before I would condemn the valves I would pressurize the cylinder with the springs still in place on the valves and smack the valve straight on with a compothane hammer. It is possible to have dirt or carbon between the valve and seat and this will usually dislodge anything and let the valve seat. If that does not cure the leaking then definately you will have to pull the heads.
Jim |
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#5 |
Pronounced "Pew-al-up"
Join Date: Oct 2002
Location: Puyallup, Washington
Posts: 845
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Thats a good idea JimKshortstep4x4 , I'll try it. They do look pretty cruddy, with alot of buildup!! Can I just tap out the guides with the heads removed?
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Classic GM Trucks of Washington Club Member 1970 FS chevy,350/350, Edelbrock cam and intake. Holley 650 carb,HEI,AT,Tangier Orange, 18's, Power Locks, Truck Photos |
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#6 |
Pronounced "Pew-al-up"
Join Date: Oct 2002
Location: Puyallup, Washington
Posts: 845
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How much can a guy expect to pay for a rebuilt set of heads?
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Classic GM Trucks of Washington Club Member 1970 FS chevy,350/350, Edelbrock cam and intake. Holley 650 carb,HEI,AT,Tangier Orange, 18's, Power Locks, Truck Photos |
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#7 |
Account Suspended
Join Date: Jan 2000
Location: Woodstock, IL
Posts: 7,020
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I just had the heads done on my 88, and it cost me $250 for 8 exhaust guides and a valve job.
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#8 |
Pronounced "Pew-al-up"
Join Date: Oct 2002
Location: Puyallup, Washington
Posts: 845
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Did you just take your heads into a machine shop and tell them what you wanted?? IO guess I need to find a good local machine shop.
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Classic GM Trucks of Washington Club Member 1970 FS chevy,350/350, Edelbrock cam and intake. Holley 650 carb,HEI,AT,Tangier Orange, 18's, Power Locks, Truck Photos |
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#9 |
My other Love
Join Date: Aug 2001
Location: Castlegar B.C. Canada
Posts: 4,085
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I f you are getting that much air through, you valve guide have got to be toast, and plus its just better to get the heads done, because it it pretty embarassing to have a brand new motor that blows blue
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![]() Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life |
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#10 |
Account Suspended
Join Date: Jan 2000
Location: Woodstock, IL
Posts: 7,020
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I took them to the machine shop, and they told me what it needed. I knew that was what it was gonna need. And the nice thing is, is that now, I have no more smoke at start up.
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