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Need advice on valve sticking in 426 hemi alum head #178635 12/30/08 12:22 AM 12/30/08 12:22 AM
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	I have an exhaust valve that sticks open. I've got less than 200 miles on this hemi I had built and I was running it hard dialing in the carb when it starting huffing and running like crap. I limped home and discovered one of the exhaust valves was hanging open about 1/8" when it should be closed. I looked inside the cylinder and there is no sign of the valve hitting the piston. What's also strange is about 50 miles earlier I decided to do a compression check and none of the cylinders would hold pressure. But since I just had the engine built I dismissed it as a faulty compression gauge. 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? Maybe the wrong kind of oil seals causing the stems to run dry? Is there something I sould be looking for or be careful of? Thanks

Re: Need advice on valve sticking in 426 hemi alum head [Re: DLP4] #178636 12/30/08 12:35 AM 12/30/08 12:35 AM
Joined: Jan 2003 Posts: 20,622 Eagle, Idaho Neil The Doctor is in.
Neil The Doctor is in. Joined: Jan 2003 Posts: 20,622 Eagle, Idaho	Rebuilt engine with new guides? Years ago my brother rebuilt a 455 Buick and the machinist installed new guides, but didn't bother to measure/ream them to the proper size. The result was two stuck valves (one on each head) several months apart. Finally when he realized what was going on he took both heads to another shop and had them reamed out for the proper clearance and it never happened again.

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
Joined: Oct 2004 Posts: 16,479 Canada CrAzYMoPaRGuY I Live Here
CrAzYMoPaRGuY I Live Here Joined: Oct 2004 Posts: 16,479 Canada	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

Re: Need advice on valve sticking in 426 hemi alum head [Re: CrAzYMoPaRGuY] #178638 12/30/08 02:15 AM 12/30/08 02:15 AM
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	That's interesting about the Buick. I hope that's all it is...still a pain but could be worse These are all new parts. Using MP aluminum heads but the engine builder replaced the guides because he said the guides the heads come with are a sloppy fit. That's what kinda makes we wonder if he fit them too tight. I can't say for sure about the seat. I pulled the hedders and used a dental mirror and a scope and from what I could see I think the seat is ok.

Re: Need advice on valve sticking in 426 hemi alum head [Re: DLP4] #178639 12/30/08 03:44 AM 12/30/08 03:44 AM
Joined: Nov 2003 Posts: 2,715 closer to Canadian beer! torkrules I'm neurotic
torkrules I'm neurotic Joined: Nov 2003 Posts: 2,715 closer to Canadian beer!	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.

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
Joined: Jan 2003 Posts: 1,791 Big Sky Country M MO_PA top fuel
MO_PA top fuel M Joined: Jan 2003 Posts: 1,791 Big Sky Country	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!!

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
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	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

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
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	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.

Re: Need advice on valve sticking in 426 hemi alum head [Re: DLP4] #178643 12/30/08 01:41 PM 12/30/08 01:41 PM
Joined: Oct 2005 Posts: 708 Mechanic Falls, Maine 4 4BBodies mopar addict
4BBodies mopar addict 4 Joined: Oct 2005 Posts: 708 Mechanic Falls, Maine	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.

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
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	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.

Re: Need advice on valve sticking in 426 hemi alum head [Re: DLP4] #178645 12/30/08 02:21 PM 12/30/08 02:21 PM
Joined: Jan 2003 Posts: 20,622 Eagle, Idaho Neil The Doctor is in.
Neil The Doctor is in. Joined: Jan 2003 Posts: 20,622 Eagle, Idaho	You can buy the tools to measure inside the valve guide holes if you want to, Powerhouse tools sells them as a kit. Then all you would have to do is take a set of calipers and measure the valve stems. Subtract the two numbers and you have your clearance. If you don't have the tools you can just take the head to the shop and have them measure one or two valve guides while your standing there.

Re: Need advice on valve sticking in 426 hemi alum head [Re: Neil] #178646 12/30/08 03:33 PM 12/30/08 03:33 PM
Joined: Oct 2005 Posts: 708 Mechanic Falls, Maine 4 4BBodies mopar addict
4BBodies mopar addict 4 Joined: Oct 2005 Posts: 708 Mechanic Falls, Maine	I didn't catch above if you were going to be taking the heads off, (I am assuming you are,) so I think you will get a good picture after the springs are off the valves. The valves will either slide in the guides good or they won't, and a simple "wiggle" test will at least give you an idea on how loose/tight they are.........then you can actually measure them with some sort of measuring tool.........maybe when they get hot they expand, and tighten up.

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
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	Quote: 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.

Re: Need advice on valve sticking in 426 hemi alum head [Re: DLP4] #178648 12/30/08 06:48 PM 12/30/08 06:48 PM
Joined: Nov 2003 Posts: 2,715 closer to Canadian beer! torkrules I'm neurotic
torkrules I'm neurotic Joined: Nov 2003 Posts: 2,715 closer to Canadian beer!	Under the valve cover there should be a part number 2531100-M (the A990 heads are the same part number without the -M). The newer heads should have a fancy "E" cast somewhere on the head denoting EDELBROCK. When I spoke to Tim at FHO with regards to my particular problem, he mentioned that there was a real problems with sizing on the guides from the folks who were machining the heads for MP (I think it was Dart). Ditto on the valve seats. I would still have a look at the seats. I had a friend of mine that was working on an engine with a set of factory '65 A990 heads. The lash kept opening up on one valve. They pulled the head and found that the seat was starting to drop out. They caught it before it became a disaster. I wish I could post pictures, but they are too big.

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
Joined: Mar 2007 Posts: 3,285 West Coast, USA jbc426 master
jbc426 master Joined: Mar 2007 Posts: 3,285 West Coast, USA	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)

Re: Need advice on valve sticking in 426 hemi alum head [Re: jbc426] #178650 12/30/08 10:49 PM 12/30/08 10:49 PM
Joined: Jan 2003 Posts: 2,431 USA S SSAAHemiFan top fuel
SSAAHemiFan top fuel S Joined: Jan 2003 Posts: 2,431 USA	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'.

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
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	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.

Re: Need advice on valve sticking in 426 hemi alum head [Re: DLP4] #178652 09/12/09 01:00 AM 09/12/09 01:00 AM
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	Well, after getting over the flu I just felt sick of working on the car and let it sit for about 10 months. Got the heads off today. 2 lobes gone on opposite banks. The wear marks on the lifters look like they never spun like they should have (mechanical flat tappet). The lobes apparently mushroomed the bottom of the lifters jamming them and the 2 valves hit the pistons bending the valves. not a good day. My first thought is the cam was not broke in properly or possibly a bad cam. It was a CompCams 557/540 solid flat tappet. Any thoughts?

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
Joined: Jan 2004 Posts: 27,347 Today? Who Knows? 1_WILD_RT Management Trainee
1_WILD_RT Management Trainee Joined: Jan 2004 Posts: 27,347 Today? Who Knows?	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

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
Joined: Mar 2005 Posts: 123 usa D DLP4 OP member
DLP4 OP member D Joined: Mar 2005 Posts: 123 usa	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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