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Hemi problems again.. valve to valve clearance #585908 01/17/10 07:38 PM 01/17/10 07:38 PM
Joined: Nov 2003 Posts: 6,293 Rock Springs Bob_Coomer OP master
Bob_Coomer OP master Joined: Nov 2003 Posts: 6,293 Rock Springs	Finally got everything mocked up, short block together etc. Despite some trouble with with the rotating assembly, (actually a rod bearing issue). Well I talked with a few of some very helpful people on this board, so I decided to do some checking for possible valve to valve issue's. I measured the distance between the valves with the valves on the seat, and didnt like what i found.. Mopar calls for .280-.300 for cams above .700 lift. I had right at .255-.260 or so. So I knew this might be a problem.. Well this cam is has wide lobe centers of 112 LSA, I degree'd and checked the cam and installed it at a 109-110 ICL so its advanced a hair. Well I was checking piston to valve clearance which is fine By the way... Anyways I was checking piston to valve clearance and noticed that the valves during overlap was very close, you can see the valve events pretty good looking through the intake port..How close..Well they didnt touch rotating the engine in the correct direction. But as I rotated the engine back words, I guess the slop in the timing chain etc retarded the cam, or changed the valve events enough that the valves clipped each other...They physically hit one another.. I had those light checker springs installed etc, so I didnt bend any valves etc. Luckily.. So now, I want to run this cam, so I must address the valves/heads to correct this issue. I know I can sink the valves, Should I sink just one valve like .050 or sink them both like .025? The valves are on diff angles so maybe I can gain more by sinking one valve compared to sinking the same amount off the other? Can the valves them self's be back cut any to gain any radial clearance?? Even if I can take as little as .008-.010 off each valve diameter would help.. Thanks in advise Bob Coomer [color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585909 01/17/10 08:22 PM 01/17/10 08:22 PM
Joined: Aug 2003 Posts: 43,157 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,157 Bend,OR USA	Clipping the valves is usally better than sinking the valve seats. Are these new valves? If so maybe grinding the valves a little first may solve the problem, if there real thick at the seat Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Hemi problems again.. valve to valve clearance [Re: Cab_Burge] #585910 01/17/10 08:39 PM 01/17/10 08:39 PM
Joined: Jan 2003 Posts: 995 Boynton Beach, Fl Rapid588 super stock
Rapid588 super stock Joined: Jan 2003 Posts: 995 Boynton Beach, Fl	Before getting too excited about them hitting i would set the valves up with the intended springs you are going to use, set with lash and then check again (going the correct direction). There will be a bit of deflection in the pushrods and the rest of valvetrain, big cams are a lot of times real close on valves missing each other, but if you do have to adjust i would cut the exhaust valve down slightly. 93 Dodge Stealth - Supercharged 526ci Hemi 93 Dodge Daytona Top Sportsman injected 588 Hemi - plus a lil NOS 67 Hemi GTX (may the 4speed with you!)

Re: Hemi problems again.. valve to valve clearance [Re: Rapid588] #585911 01/17/10 08:51 PM 01/17/10 08:51 PM
Joined: Nov 2003 Posts: 6,293 Rock Springs Bob_Coomer OP master
Bob_Coomer OP master Joined: Nov 2003 Posts: 6,293 Rock Springs	Quote: Before getting too excited about them hitting i would set the valves up with the intended springs you are going to use, set with lash and then check again (going the correct direction). There will be a bit of deflection in the pushrods and the rest of valvetrain, big cams are a lot of times real close on valves missing each other, but if you do have to adjust i would cut the exhaust valve down slightly. My machist actually told me the same thing. During the time that they were hitting. There was NO head gasket, the valve lash was set to zero. I dont think the head gasket would matter, but the valve lash might make a diff. But even MP knew it might be problem with large lift and large duration cams..And Ma Mopar called for .300 between the valves with them on the seat...I know for fact I have only .255-.260 max..Si its close. If two years down the road, and I have some valve guide wear..kaboom..its too close for comfort for me really. I couldnt measure it, but at the closest point it was only .020 inch .025 tops. Last edited by Bob_Coomer; 01/17/10 08:52 PM. [color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585912 01/17/10 09:00 PM 01/17/10 09:00 PM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	I would cut a little off each valve first,drop the seats a little second or a little of both. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Hemi problems again.. valve to valve clearance [Re: B G Racing] #585913 01/17/10 09:27 PM 01/17/10 09:27 PM
Joined: Nov 2003 Posts: 6,293 Rock Springs Bob_Coomer OP master
Bob_Coomer OP master Joined: Nov 2003 Posts: 6,293 Rock Springs	Quote: I would cut a little off each valve first,drop the seats a little second or a little of both. I was hoping you would chime in Bob.. I dug out my Old MP engine book, and according to this, are you referring to cutting some off the margin? Also I wrote down some notes you told me and some angled for cutting... Quote: Chrysler recommends .265 for cams in the .600 lift range and .300 for cams in the .700 lift range.Cut the exhaust valve parallel to the stem and cut the intake 29 degrees to valve stem ,or sink the valves.This is what I like about the Indy Legend head with the moved exhaust valve. I would still use a steel gage,the valve can easly cut quite a few .000s into the aluminum. [color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585914 01/17/10 10:32 PM 01/17/10 10:32 PM
Joined: Jul 2008 Posts: 608 Boise M Moparteacher mopar
Moparteacher mopar M Joined: Jul 2008 Posts: 608 Boise	Yea..install the actual springs, set zero lash, pull your pistons and rods, leave the crank, assemble and install both heads on the block. Now confirm actual v-v clearance with a feeler gauge up reaching through the bottom.

Re: Hemi problems again.. valve to valve clearance [Re: Moparteacher] #585915 01/17/10 10:42 PM 01/17/10 10:42 PM
Joined: Nov 2003 Posts: 6,293 Rock Springs Bob_Coomer OP master
Bob_Coomer OP master Joined: Nov 2003 Posts: 6,293 Rock Springs	Quote: Yea..install the actual springs, set zero lash, pull your pistons and rods, leave the crank, assemble and install both heads on the block. Now confirm actual v-v clearance with a feeler gauge up reaching through the bottom. I dont think I need too...I know they need work..The Mopar Jury has reached a decision. If I had .280 between the valves yea..maybe...But Im almost .050 from recommended minimal valve to valve clearance LOL [color:"red"]65 Hemi Belvedere coming soon [/color] [color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585916 01/17/10 11:54 PM 01/17/10 11:54 PM
Joined: Oct 2004 Posts: 1,752 detroit area M moderncylinder top fuel
moderncylinder top fuel M Joined: Oct 2004 Posts: 1,752 detroit area	hey bob i run .900 lift and .260 valve to valve,,,, ma mopar must have missed the boat on me.... the mopar jury must not apply to me.. do not go on assumption.... check your actual clearance with springs, lash up through the bottom of the cylinder,, if you have .025 run it and pretty much noone runs .300 valve to valve anymore,, unless you are running a 426 with a cam from 1970

Re: Hemi problems again.. valve to valve clearance [Re: moderncylinder] #585917 01/18/10 07:53 AM 01/18/10 07:53 AM
Joined: Dec 2007 Posts: 12,587 Great Neck,LI,new york hemi-itis I Live Here
hemi-itis I Live Here Joined: Dec 2007 Posts: 12,587 Great Neck,LI,new york	Quote: hey bob i run .900 lift and .260 valve to valve,,,, ma mopar must have missed the boat on me.... the mopar jury must not apply to me.. do not go on assumption.... check your actual clearance with springs, lash up through the bottom of the cylinder,, if you have .025 run it and pretty much noone runs .300 valve to valve anymore,, unless you are running a 426 with a cam from 1970 Priceless info right there!!I would never have thought...... HEMI-ITIS has no cure. My condition is fully BLOWN!!

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585918 01/18/10 08:47 AM 01/18/10 08:47 AM
Joined: Aug 2003 Posts: 1,313 Charlotte, NC L LSP pro stock
LSP pro stock L Joined: Aug 2003 Posts: 1,313 Charlotte, NC	Check all the valve to valve measurements on the seat on each chamber. Note the chamber with the closest measurement, pull that piston/rod out and mock up the head/actual valvetrain on that cylinder. See that you have the minimum of .025" as Jeff said at valve overlap. I would leave the intakes alone, and sink/clip the exhausts to get your clearance. Careful about following the mopar "bible" too much, that info is way outdated.

Re: Hemi problems again.. valve to valve clearance [Re: LSP] #585919 01/18/10 08:57 AM 01/18/10 08:57 AM
Joined: Nov 2004 Posts: 3,619 Norwich CT USA Defbob master
Defbob master Joined: Nov 2004 Posts: 3,619 Norwich CT USA	Quote: Check all the valve to valve measurements on the seat on each chamber. Note the chamber with the closest measurement, pull that piston/rod out and mock up the head/actual valvetrain on that cylinder. See that you have the minimum of .025" as Jeff said at valve overlap. I would leave the intakes alone, and sink/clip the exhausts to get your clearance. Careful about following the mopar "bible" too much, that info is way outdated. it says the purple cam is the most powerful cam for a 440 Bob, I would listen to ModernCylinder

Re: Hemi problems again.. valve to valve clearance [Re: Defbob] #585920 01/18/10 09:08 AM 01/18/10 09:08 AM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	You can very easily check the clearence with a wire gage through the intake or exhaust port.Listen to whoever,I would look for a minimum of .035. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Hemi problems again.. valve to valve clearance [Re: B G Racing] #585921 01/18/10 02:32 PM 01/18/10 02:32 PM
Joined: Aug 2004 Posts: 2,128 sweden S sshemi top fuel
sshemi top fuel S Joined: Aug 2004 Posts: 2,128 sweden	Are you saying that the int and ex valves in the same cylinder are hitting each other when you turn the motor over only in one diretion????? How the %#!" is that possible??? Is the cam twisting in one direction?

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585922 01/18/10 03:05 PM 01/18/10 03:05 PM
Joined: Feb 2005 Posts: 232 Lansing, MI M MuscleMike enthusiast
MuscleMike enthusiast M Joined: Feb 2005 Posts: 232 Lansing, MI	FYI: odds are you will have intake pushrod clearance issues on #1 &#8. The way they machined those old Mega blocks the intake pushrods hit the block. Mike @MM

Re: Hemi problems again.. valve to valve clearance [Re: MuscleMike] #585923 01/18/10 03:43 PM 01/18/10 03:43 PM
Joined: Mar 2006 Posts: 9,910 Eighty Four, PA B G Racing master
B G Racing master Joined: Mar 2006 Posts: 9,910 Eighty Four, PA	With close center long duration camshafts it is advisable to have a minimum of .280/.290 between the valves on the seat.Jeff may be getting away with .025 at the valve to valve intersecting point and only have .260 between the valves on the seat with the design of cam he is using.I would not and never recommend you use his numbers with that cam I gave you.The slightest deviation could spell disaster, a loose guide,slight varaying position of a guide center,or a side loading of the valve from unstabe or poor geometry.Even a pushrod bind can cause enough deflection in a long valve with a 5/16 stem to cause concern.I'am not doubting Jeff's claim,after all he is the head guru for race applications and especially SS/AH Hemis,and he would know better than any of us.If your that confident in his recommendation go for it,what do you have to loose?I stand buy what I said,I would rather be conservative and safe than be sorry later.Bob your not building a SS/AH granade and trimming or sinking those valve won't kill a 100hp for sure and you will sleep better.What ever you decide,good luck. P.S.FYI, Jeff it is an early style cam. Last edited by B G Racing; 01/18/10 08:02 PM. [IMG]http://i430.photobucket.com/albums/qq21/ajcasini/max_zpsdppwd9km.jpg[/IMG]

Re: Hemi problems again.. valve to valve clearance [Re: sshemi] #585924 01/18/10 03:58 PM 01/18/10 03:58 PM
Joined: Aug 2003 Posts: 43,157 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,157 Bend,OR USA	Quote: Are you saying that the int and ex valves in the same cylinder are hitting each other when you turn the motor over only in one diretion????? How the %#!" is that possible??? Is the cam twisting in one direction? Cam does not twist, it is a physcical contact on the overlap of the valves, not unusual with bigger cams on the 426 hemi motors, be very careful when setting the cam up and make sure to check them like what has already been said to do the bigger the lift(.700+ and duration (286+)the more likely you can have a problem Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Hemi problems again.. valve to valve clearance [Re: Bob_Coomer] #585925 01/18/10 03:59 PM 01/18/10 03:59 PM
Joined: Dec 2005 Posts: 4,231 State of retirement 5 52savoy master
52savoy master 5 Joined: Dec 2005 Posts: 4,231 State of retirement	Besides clipping the valves for clearance, no one mentioned(or I missed it) anywhere about cutting the exhaust valve to 1.900. I agree with BG..old school cams should be set up the old school way. I run a Crane R290 in my 477 and it's clipped with 1.900 exh valves. It wouldn't work(clear) any other way even with moving the cam timing around.

Re: Hemi problems again.. valve to valve clearance [Re: Cab_Burge] #585926 01/18/10 04:13 PM 01/18/10 04:13 PM
Joined: Aug 2004 Posts: 2,128 sweden S sshemi top fuel
sshemi top fuel S Joined: Aug 2004 Posts: 2,128 sweden	Quote: Quote: Are you saying that the int and ex valves in the same cylinder are hitting each other when you turn the motor over only in one diretion????? How the %#!" is that possible??? Is the cam twisting in one direction? Cam does not twist, it is a physcical contact on the overlap of the valves, not unusual with bigger cams on the 426 hemi motors, be very careful when setting the cam up and make sure to check them like what has already been said to do the bigger the lift(.700+ and duration (286+)the more likely you can have a problem But only when turning it over in one direction???

Re: Hemi problems again.. valve to valve clearance [Re: Cab_Burge] #585927 01/18/10 04:16 PM 01/18/10 04:16 PM
Joined: Jan 2003 Posts: 19,363 Las Vegas Al_Alguire I Live Here
Al_Alguire I Live Here Joined: Jan 2003 Posts: 19,363 Las Vegas	Good luck with it but if it were me I would mock it up as it is going to be run, lash, springs and all. Then see what you get. BTW the comment about the block and pushrod clearance is spot on, it is gonna need some grinding, even my World block needed a little with an appropriately sized pushrod. "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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