Valvetrain help |
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Jordanbrown123
Member Joined: 13-July-2017 Location: BC, Canada Status: Offline Points: 49 |
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Posted: 01-September-2017 at 9:47AM |
Just wondering if anyone has ever seen this type of wear and damage before? The valve stem is almost being machined by the keepers or somthing in the first pic.
I also noticed a couple valves were sitting much lower causing the rocker to hit the retainer. How could they be sitting lower than the rest? Bent or somthing? i cant tell if they are bent with just my eye. How can i check? Maybe the valve stem is getting machined down from the flakes of steel coming off the retainer? What do you guys think? Thanks |
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71 Ranchero, 351w.
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6072 |
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you're well into the violent dis-assembly countdown
the locks are hammering the grooves out of the stems and the retainers are moving upwards and contacting the rockers. what lets go first is anybody's guess but the result will be the same, dropped valve(s) leading to a total catastrophic event 99% of the time any details on the build, engine, cam grind, spring pressures yada yada yada ? what does she tach to?
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72 GT Ute
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Jordanbrown123
Member Joined: 13-July-2017 Location: BC, Canada Status: Offline Points: 49 |
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Yikes. Looks like ill be rebuilding these heads. Or buying knew ones..
The block is a 1970s 302w. The bottom end is stock. And the heads are Fomoco c80E-J (1968?). CompCams roller tip rockers and stock everything else (probably) Maybe the springs are aftermarket (blue paint line on them. Sorta) Car never ran properly. And had coolant blockages 3 inches thick in the intake making it overheat obviously. It was sitting for nearly 20 years before i got it. No idea how high the rpm will go. Dosent have a tach wired up and i barely drove it. Im guessing this is just symptoms of a really worn out head and engine. No idea of the miles on it. |
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71 Ranchero, 351w.
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6072 |
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OK this is the spew motor, i didn't make the connection. C8xx yes 1968 model year castings could've been in production until the next iteration came about but they were coming fast & furious back then so likely 1968 ... on a 197x? block
that thing has had a hard life, the valves are cheap replacements or both are you familiar with Alex's parts? https://www.alexsparts.com/ sbf heads are PITA because there's countless combinations of valve tip heights, retainers & rocker styles some of which are not compatible. be careful choosing parts, i'd start fresh with everything new / don't re-use anything. nice time to match the springs to a fresh cam
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72 GT Ute
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Jordanbrown123
Member Joined: 13-July-2017 Location: BC, Canada Status: Offline Points: 49 |
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lol the spew motor. Yup thats me.
Thanks for the input guys. Im totally rebuilding this damn thing now. Im gona catch any other issues before they bite me in the ass down the road.
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71 Ranchero, 351w.
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6072 |
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a quality 1 piece stainless steel valve is the way to go
have you measured the valve head & stem diameters yet? are the castings serviceable or are you replacing them? the GT40/P heads are an alternative but can create an issue with spark plug & exhaust clearance build an Edelbrock Clevor?
Edited by Rockatansky - 09-September-2017 at 6:22AM |
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72 GT Ute
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Jordanbrown123
Member Joined: 13-July-2017 Location: BC, Canada Status: Offline Points: 49 |
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Havent measured anything or done much since taking the thing apart. School started so i have to pay for that instead of parts for now.
Im going to take the heads and block to a machine shop somewhere and get them checked out and cleaned before i do anything else. If the heads are screwed im probably going to get some edelbrock performer rpm heads or somthing. Not sure what will work for my set up. Might change out the cam depending on if its worn out or not. |
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71 Ranchero, 351w.
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Rockatansky
Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6072 |
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i'd pretty much consider the cam & lifters disposable. with such a popular platform you can probably pick up a complete running, rebuilt or crate engine for less than you'll pour into yours
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72 GT Ute
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