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  #16 (permalink)  
Old 04-30-2013, 06:27 PM
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Originally Posted by david-b View Post
Tech, makes perfect sense. Would have never thought of that. I don't remember the exact shave done by remember it was very little.
Just so everyone reading this is clear on what I'm saying, that's not the head surface I'm talking about. You're saying the shop took a slight skim off the block mating surface of the heads, probably just to make sure it was parallel and would hold a head gasket. The surface I'm talking about is the intake manifold mating surface that was cut by the head manufacturer at the time of manufacture. It could be off by any number of degrees or it could be dead on the money, matching the intake manifold mating surface exactly. Also, consider that the block being machined lolly-gagged could result in the same problem. If one end of the block is higher than the other, (example: block deck height on one bank at the front of the block measures 9.016". Block deck height on the other bank at the front of the block measures 9.026") then when you bolt the heads on, one head is higher than the other and no matter how true the head/manifold mating surfaces are, there is no way in hell that the manifold will seal up to the heads. You have to begin with cutting the block decks on a Tru-Deck mill, exactly 90 degrees apart and exactly parallel with the main bearing bore.

And of course, the heads could be dead-nuts on the money, but the intake manifold could be cut askew. Like I said above, sacrifice a set of gaskets and verify the seal yourself.

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  #17 (permalink)  
Old 04-30-2013, 10:54 PM
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Not saying tech is wrong but running a compression and leak down test is free. I'd start there.
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Old 05-25-2013, 03:20 PM
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Wanted to bring this thread back up. After some issues non related to the car, I finally got the plugs regaped to .040" and a fuel pressure gauge in the car. For the first start of the day, the gauge is 0 before any cranking. Then once she gets going, pressure goes to 9psi and stays there. Meanwhile, the car is rich and dies many times without keeping the throttle open some. After she warmed up (don't remember the exact time because was doing other stuff) the gauge was reading just under 5psi and runs like a champ then.

The ONLY change I did in the meantime was add some trans fluid. Pretty sure that didn't make a difference.
Why would it change like? How can I get it to not be at 9psi while warming up? This is a mechanical pump (Holley) doing to an Edlebrock. Had a filter inbetween there, but that's all. Any ideas?
Thanks
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Old 05-26-2013, 03:24 PM
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As i been doing more research, I'm wondering... I don't have a fuel return line setup on this car. Have fuel line to pump, pump to filter, filter to carb. Return line is capped. Have a vac line from the tank that ran to emissions canister that is currently kept vented to atmosphere. Seems people have similar problems when fuel return is capped and not vented, however I thought the vac line was sufficient enough. Any ideas?
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  #20 (permalink)  
Old 05-27-2013, 08:44 AM
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Quote:
Originally Posted by techinspector1 View Post
Just so everyone reading this is clear on what I'm saying, that's not the head surface I'm talking about. You're saying the shop took a slight skim off the block mating surface of the heads, probably just to make sure it was parallel and would hold a head gasket. The surface I'm talking about is the intake manifold mating surface that was cut by the head manufacturer at the time of manufacture. It could be off by any number of degrees or it could be dead on the money, matching the intake manifold mating surface exactly. Also, consider that the block being machined lolly-gagged could result in the same problem. If one end of the block is higher than the other, (example: block deck height on one bank at the front of the block measures 9.016". Block deck height on the other bank at the front of the block measures 9.026") then when you bolt the heads on, one head is higher than the other and no matter how true the head/manifold mating surfaces are, there is no way in hell that the manifold will seal up to the heads. You have to begin with cutting the block decks on a Tru-Deck mill, exactly 90 degrees apart and exactly parallel with the main bearing bore.

And of course, the heads could be dead-nuts on the money, but the intake manifold could be cut askew. Like I said above, sacrifice a set of gaskets and verify the seal yourself.
25 years or so ago we used to put a vacuum Gage on the dipstick tube with engine running and if there was 2 lbs or more of vacuum then went looking for a intake leak (usually found on the valley side of the intake). The engine usually had a cylinder that didn't run. BTW, finding a vacuum Gage that reads in 1 lb increments can be hard to do. Of course these were stock engines with ample vacuum.
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  #21 (permalink)  
Old 05-27-2013, 03:45 PM
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Originally Posted by techinspector1 View Post
The plot thickens.
If the angle of the heads and the angle of the intake manifold do not match exactly, top to bottom, there is a possibility that the gaskets do not seal the ports on the heads all the way around the ports. If the ports are gapped open a little on the bottom, the motor can suck in oily vapors from the crankcase on the intake stroke. It could be 1 or more cylinders that are affected. Maybe some are sealed up while others are open to the crankcase. Only way to know is to look at the intake gaskets and verify that the gaskets are pinched all the way around the ports. That's why I recommend sacrificing a set of intake gaskets on the initial build. Torque the heads down for the last time, then install and torque the intake manifold. Let it sit overnight, then remove the manifold and examine the gaskets for being pinched all the way around the ports. If they are, great, use another set of new gaskets and torque the manifold on for good. If not, you have some machine work in your future.
have been reading this thread, I think you have a very good point . and I will also do that test . I had oil on 5 and 6 plugs, and now suspect that could be a issue for me . good job !! cheers
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  #22 (permalink)  
Old 05-29-2013, 07:53 AM
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Quote:
Originally Posted by david-b View Post
Wanted to bring this thread back up. After some issues non related to the car, I finally got the plugs regaped to .040" and a fuel pressure gauge in the car. For the first start of the day, the gauge is 0 before any cranking. Then once she gets going, pressure goes to 9psi and stays there. Meanwhile, the car is rich and dies many times without keeping the throttle open some. After she warmed up (don't remember the exact time because was doing other stuff) the gauge was reading just under 5psi and runs like a champ then.

The ONLY change I did in the meantime was add some trans fluid. Pretty sure that didn't make a difference.
Why would it change like? How can I get it to not be at 9psi while warming up? This is a mechanical pump (Holley) doing to an Edlebrock. Had a filter inbetween there, but that's all. Any ideas?
Thanks
Anyone have any thoughts on what's going on with this here? I'm stumped as to why it would be changing like this.
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