Re: Mega block 528 - plugs - nitrous - Questions
[Re: NITROUSN]
#3023228
03/12/22 01:56 PM
03/12/22 01:56 PM
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Joined: Sep 2003
Posts: 20,268 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 20,268
north of coder
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Is that the seal with the little spring tension showing in there? About as clear as I can get from my phone and a pen spot light on it. That's a valve seal. and it looks deformed, maybe needing replaced ?
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: moparx]
#3023603
03/13/22 02:16 PM
03/13/22 02:16 PM
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Joined: May 2018
Posts: 36 FL
sixtycycle
OP
member
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OP
member
Joined: May 2018
Posts: 36
FL
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Ok thanks, hoping for some input on the leak down numbers too. And what are the best valve stem seals I can get. Indy -1 heads, what other info do I need to provide? Thanks
Last edited by sixtycycle; 03/13/22 02:18 PM.
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: sixtycycle]
#3023787
03/13/22 10:51 PM
03/13/22 10:51 PM
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Joined: Aug 2003
Posts: 43,739 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,739
Bend,OR USA
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Viton push on seals is what I would and due use, not the old race Teflon type: tsk: You need to know the outer diameter of the valve guide boss and the valve stem size as well as make sure the valve retainer or valve keepers do NOT hit the seal, minimum of .060 clearance at max lift works good for me If they hit the seal it ruins them so they don't keep oil out of the combustion chambers I usually buy mine from Goodson Tool and Motor supply, I don't have any of the better ones in stock so it is time to make up an order and restock now. I'm almost positive that the 440-1 heads have 11/32valve stem size valves in them form Indy, measure yours to make sure they haven't been changed The two in the picture are not the really good race ones, they are more for standard street motor rebuild
Last edited by Cab_Burge; 03/13/22 11:00 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: Cab_Burge]
#3023903
03/14/22 11:13 AM
03/14/22 11:13 AM
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Joined: May 2018
Posts: 36 FL
sixtycycle
OP
member
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OP
member
Joined: May 2018
Posts: 36
FL
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Ok thanks, now for the question that I hate to ask but remember first time working on a heads alone... I have the tools but what I need to know is, the process and pitfalls to change the seals with the head on the engine.
1. Remove the valvetrain/rockers keeping orientations etc. in place and notate any measurements/settings 2. Roll the engine around to ensure that the cylinder I'm working on has both the intake and exhaust valves closed. (pressure off the springs) 3. Air up the cylinder to keep the valves from falling in. 4. Compress and remove the springs 5. Remove and replace the seals 6. Install springs/keepers 7. Install valvetrain/rockers etc 8. Adjust valves to cam card specs
Are there any pitfalls or tricks to this process? I would think its just a matter of putting back the I take it off and then setting the lash...? Which I see as being .016 intake and .020 exhaust from reading my card. EOIC Method... Thanks in advance
Last edited by sixtycycle; 03/14/22 11:41 AM.
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: sixtycycle]
#3024207
03/15/22 01:05 PM
03/15/22 01:05 PM
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Joined: Jan 2003
Posts: 19,543 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,543
Las Vegas
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34% is pretty much a a sign you need to dig deeper. While a borescope sounds like a good idea, it is entirely likely you not see anything with it. Unless is a blaringly obvious problem like a chunk of valve missing, which you may not even be able to see. I woudl start by yanking that head off. Could be any number of things but its not going to be fixed with a borescope.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: NITROUSN]
#3024230
03/15/22 02:06 PM
03/15/22 02:06 PM
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Joined: Jan 2003
Posts: 19,543 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,543
Las Vegas
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What I find odd is it had decent compression. You would think with that much leak down the compression would of been lower. Can be LOTS of reasons foe the leakdown number. In this case it seems he can hear it out the exhaust side when no other cylinder is doing it. Could be a bad seat or valve issue could be a piece of carbon or some other foreign object is causing it. He seems concerned that is is hurt so best way to find out at this point is either remove the head or send it. FWIW I have seen stuff leakdown 30%+ and run pretty well especially when thats leaking out the exhast side. We dont generally leak stuff down that often, only when we find an issue with pumping being way down or we have lost vaccum. AS stated before sometimes leakdowns can be misleading.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: Al_Alguire]
#3024238
03/15/22 02:17 PM
03/15/22 02:17 PM
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Joined: Jan 2003
Posts: 18,432 UPPER MICHIGAN, MARQUETTE COUN...
NITROUSN
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 18,432
UPPER MICHIGAN, MARQUETTE COUN...
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What I find odd is it had decent compression. You would think with that much leak down the compression would of been lower. Can be LOTS of reasons foe the leakdown number. In this case it seems he can hear it out the exhaust side when no other cylinder is doing it. Could be a bad seat or valve issue could be a piece of carbon or some other foreign object is causing it. He seems concerned that is is hurt so best way to find out at this point is either remove the head or send it. FWIW I have seen stuff leakdown 30%+ and run pretty well especially when thats leaking out the exhast side. We dont generally leak stuff down that often, only when we find an issue with pumping being way down or we have lost vaccum. AS stated before sometimes leakdowns can be misleading. I agree on what you are saying. Reading from the beginning I suspect this motor has a history and has been hurt.
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Re: Mega block 528 - plugs - nitrous - Questions
[Re: Cab_Burge]
#3042797
05/16/22 01:15 PM
05/16/22 01:15 PM
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Joined: Aug 2003
Posts: 4,745 On the parachute mount
n20mstr
master
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master
Joined: Aug 2003
Posts: 4,745
On the parachute mount
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Big "depends" here on the temp. A bb Mopar has siamese exh ports so it needs good cooling in that area, especially with nitrous. You have a Megablock, shouldnt move around too much hot to cold, IF the carb works well, you should stage at 100* . That would require towing up . Like i said, the carb must be tuned for this temp so dont go try it and say it didnt work...LOL Like i said this is for a decent amount of nitrous use on a BB mopar....i dont want to argue it, just saying what i have been instructed to do by a very reputable builder and what has worked for me. I have a Dale Cubic carb and it goes on the brake no problem, usually stage at 90 to 110*
....BAD A$$ STREET CAR.....
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