Re: Need advice on valve sticking in 426 hemi alum head
[Re: DLP4]
#178637
12/30/08 12:52 AM
12/30/08 12:52 AM
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CrAzYMoPaRGuY
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Are you sure it's the valve hanging open or could it be the seat in the head moving around? Is it aluminum or iron heads? I would pull the head and look before guessing to be honest..? Could be guide clearance, or a number of things.
CrAzYMoPaRGuY
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: DLP4]
#178640
12/30/08 10:06 AM
12/30/08 10:06 AM
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Joined: Jan 2003
Posts: 1,791 Big Sky Country
MO_PA
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Quote:
I'm in the precoess of pulling the heads but I was wondering if any of you guys that know engines can tell me what to look for?
If those were my cylinder heads I'd locate a competent engine builder!! The guy that built your heads may correct things for you by reaming the guides TOO much which create a new problem.
Valve guide clearance is VERY important!!
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: torkrules]
#178641
12/30/08 12:12 PM
12/30/08 12:12 PM
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Quote:
Are these the new Mopar heads or the older ones that look like the old A990 heads? If they are the older ones, they are notorious for having problems.
After suffering through a year of using an excessive amount of oil, it turns out that all 16 guides had excessive clearance. Also, they have been known to drop seats. This usually shows up either when they are first run on the dyno or after a few miles. I spoke to Tim at FHO about this and he confirmed the problems with these heads.
I'd get them off and go through them pretty thoroughly.
How do I know which heads I have? Is there a casting series or something to look for?
It survived the dyno and I'm at about 200 miles.
Funny you mentioned oil consumption. I'm blowing through a lot of oil. But that would contradict the tight clearance theory.
When I get 'er opened up I'm take some pictures and post. thanks everyone
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: DLP4]
#178642
12/30/08 12:22 PM
12/30/08 12:22 PM
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Quote:
If those were my cylinder heads I'd locate a competent engine builder!! The guy that built your heads may correct things for you by reaming the guides TOO much which create a new problem.
Valve guide clearance is VERY important!!
That kind of leads to my thoughts about valve stem lubrication. Of course, I won't know 'till I get it apart but I'm wondering if maybe the clearance is ok but the lubrication is not. He seemed pretty concerned about getting the clearances correct...of course that doesn't mean they are so we'll find out.
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: 4BBodies]
#178644
12/30/08 02:01 PM
12/30/08 02:01 PM
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Quote:
It sounds like the guide got dry (of oil) and the valve siezed to me. Could the machinist have made the clearance too tight for the valves? My books say .001 to .003 thousandths clearance, I use the pilots from my valve seat grinder to measure them, they have been pretty accurate to date. Good luck, I hope you figure it out.
I've never done a valve job but I have experience machining non-automotive stuff. Should each stem be measured and each guide reamed to fit? Seems the stems should be consistant but I don't know. I want to figure out what the problem is before I send it off to someone to have it fixed.
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: 4BBodies]
#178647
12/30/08 04:18 PM
12/30/08 04:18 PM
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I didn't catch above if you were going to be taking the heads off, (I am assuming you are,)
Yes, I'm pulling the heads. Started last night but there is a lot of stuff in the way. Hopefully I'll the one head off tonight that has the offending valve and we'll see what's there.
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: torkrules]
#178649
12/30/08 08:02 PM
12/30/08 08:02 PM
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jbc426
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Do a search on the microsoft site about Microsoft Toys and then look for the resizing tool. It works great and is as easy as a right click from your mouse.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: SSAAHemiFan]
#178651
01/01/09 12:47 AM
01/01/09 12:47 AM
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Quote:
Tight guides and seat issues are very common with MP heads.
I noticed you said you were running it hard AND fiddling with the tune. Both of those items COULD have contributed (over-rev or mixture problems). Not pointing fingers just thinking out loud.
Pulling the heads will tell the story. Keep us updated please. Hopefully it's a simple fix for ya'.
I'm sick with the flu so it's going to be couple days before I finish getting the heads off.
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: DLP4]
#178653
09/12/09 02:30 AM
09/12/09 02:30 AM
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Joined: Jan 2004
Posts: 27,347 Today? Who Knows?
1_WILD_RT
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First thought what oil was used/is being used.. Are you familiar with ZDDP, what it does & the fact it's been removed from most oil... http://www.zddpforum.com/forum/viewtopic.php?f=2&t=7Second thought were lighter springs used during cam break-in?? There are plenty of other questions but those two are biggest... Unfortunately flat cams are all to common these days & unfortunately when the lobes go they send metal particles throughout the whole engine... Often damaging pistons, bearings cylinder bores & sometimes cylinder heads... Your whole engine really needs to come apart for a thorough inspection Also I would strongly suggest a roller cam to eliminate the potential of this happening again
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Re: Need advice on valve sticking in 426 hemi alum head
[Re: 1_WILD_RT]
#178654
09/12/09 02:59 AM
09/12/09 02:59 AM
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Quote:
First thought what oil was used/is being used.. Are you familiar with ZDDP, what it does & the fact it's been removed from most oil... http://www.zddpforum.com/forum/viewtopic.php?f=2&t=7 Second thought were lighter springs used during cam break-in?? There are plenty of other questions but those two are biggest...
Unfortunately flat cams are all to common these days & unfortunately when the lobes go they send metal particles throughout the whole engine... Often damaging pistons, bearings cylinder bores & sometimes cylinder heads...
Your whole engine really needs to come apart for a thorough inspection
Also I would strongly suggest a roller cam to eliminate the potential of this happening again
I'm not sure what the engine builder did or didn't do. I suppose it's water under the bridge at this point.
I was considering a roller because of not requiring break-in and also because the roller tolerates low speeds and idling better but most of the roller cams I've seen are pretty tall and I want to keep the car driveable. I need to figure out what direction to go pretty quick though so I can get it back together. Should do a complete tear-down like you said.
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