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#1 |
Registered User
Join Date: Mar 2009
Location: winthrop, wa.
Posts: 33
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valve adjustment. help?
my buddy decided he wanted to adjust the valves in my 72 402. we tightened them down until we could not spin the push rod and then tightened them a 1/2 turn more. we followed a pattern we saw on line that allowed us to adjust half of them then rotate 1 turn and adjust the rest of them. well it sounds ok idling but put it into gear and it almost dies no power. whats wrong?
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#2 |
Registered User
Join Date: Apr 2008
Location: riverhead,new york
Posts: 160
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Re: valve adjustment. help?
Your Valves are too tight. Back each nut uo until you hear a slight clicking sound. Then tighten just a half turn. That's 180*. Do this immediately or you may wipe out your Camshaft.
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#3 |
Registered User
Join Date: Oct 2005
Location: Northern Arkansas
Posts: 1,132
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Re: valve adjustment. help?
I agree, way too tight. You only tighten until initial drag is felt while spinning the pushrod with your fingers. If you tightened until you could not spin them, you probably went a couple turns too much.
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#4 |
Account Suspended
Join Date: Oct 2009
Location: Sammamish, WA
Posts: 2,404
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Re: valve adjustment. help?
Don't adjust valves with the engine running.
Unless you have a radical cam, the companion cylinder method is quick and easy. Key point is as above...the very first time you feel any drag at all is zero lash. http://www.carcraft.com/howto/ccrp_0...aft/index.html |
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#5 | |
Registered User
Join Date: Nov 2009
Location: Oregon City, OR
Posts: 146
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Re: valve adjustment. help?
Quote:
![]() Ticker, I just noticed all of the helpful links in your signature. ![]()
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Thanks, Aaron Life is about making dreams come true, stop dreaming and make life happen. 64 GMC Project MY_YOUTUBE_VIDEOS To keep an opened mind- speculation is devine. Assumptions always lead to a dead end! Last edited by Phlebmaster; 02-23-2010 at 04:39 PM. |
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#6 |
Registered User
Join Date: Mar 2009
Location: winthrop, wa.
Posts: 33
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Re: valve adjustment. help?
well the mechanic said the cam is gone, but it was running with an intake back fire with and acceleration before, and now it keeps trying to die when put in gear.
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#7 |
Account Suspended
Join Date: Oct 2009
Location: Sammamish, WA
Posts: 2,404
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Re: valve adjustment. help?
If you tighted down the cam too much...then you'd have wiped the lobes
![]() The backfire was likely timing and/or fuel related. Last edited by Ticker; 02-23-2010 at 05:16 PM. |
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#8 |
Registered User
Join Date: Mar 2009
Location: winthrop, wa.
Posts: 33
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Re: valve adjustment. help?
we timed it to -9 and dialed in the carb before we ever took off the valve covers.
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#9 |
Registered User
Join Date: Oct 2005
Location: Overland Park, Ks.
Posts: 5,216
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Re: valve adjustment. help?
What do you mean by "-9". You may have it timed too slow & your valves are OK. If it was popping back through the carb on accel. your mech. is probably right. You may have a bad cam. Run or turn the engine with the covers off & watch for a valve that barely opens.
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#10 |
Registered User
Join Date: Mar 2009
Location: winthrop, wa.
Posts: 33
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Re: valve adjustment. help?
so the mechanic wants to charge me 1000 to replace the cam. how hard is it?
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#11 |
Registered User
Join Date: Mar 2009
Location: winthrop, wa.
Posts: 33
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Re: valve adjustment. help?
i guess i mean 9 off top dead center
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#12 | |
Registered User
Join Date: Nov 2009
Location: Oregon City, OR
Posts: 146
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Re: valve adjustment. help?
Quote:
Here is a video I made of the swap> This one might give more detail of the front of the block and cam gears Put the engine at TDC for # 1, Pull the distributor (after you mark it) Then the intake then the grill, radiator, water pump and the stuff attached, then the crank pulley/harmonic balancer, then the timing cover. Then pull the timing gear/ chain. Pull the fuel pump (there is a fuel pump lever actuator rod in the block) Loosen the rocker adjuster nuts, pull the push rods, then the lifters (keeping them in order). The cam should just slide right out. (be careful not to bung up the cam bearings) Do the reverse to put it all back together. ![]()
__________________
Thanks, Aaron Life is about making dreams come true, stop dreaming and make life happen. 64 GMC Project MY_YOUTUBE_VIDEOS To keep an opened mind- speculation is devine. Assumptions always lead to a dead end! Last edited by Phlebmaster; 02-23-2010 at 06:15 PM. |
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#13 |
Account Suspended
Join Date: Oct 2009
Location: Sammamish, WA
Posts: 2,404
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Re: valve adjustment. help?
"off TDC" can go either before (BTDC) or after (ATDC) - 9 BTDC is reasonable, the other way - you'd get the issues you're noting or worse.
You can ABSOLUTELY do this swap on your own with a little time and basic hand tools - 4 hours or so. I have to note...that depending on how far the cam is gone, having the metal particulate in the engine is not good ![]() ![]() Last edited by Ticker; 02-23-2010 at 06:46 PM. |
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#14 |
Registered User
Join Date: Nov 2009
Location: Oregon City, OR
Posts: 146
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Re: valve adjustment. help?
I almost forgot to mention........ You want to make sure you replace the lifters with the cam. It is not wise to reuse lifters unless you have them re-surfaced.
New ones are not that expensive. ![]()
__________________
Thanks, Aaron Life is about making dreams come true, stop dreaming and make life happen. 64 GMC Project MY_YOUTUBE_VIDEOS To keep an opened mind- speculation is devine. Assumptions always lead to a dead end! Last edited by Phlebmaster; 02-23-2010 at 06:59 PM. |
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#15 |
Registered User
Join Date: Oct 2005
Location: Northern Arkansas
Posts: 1,132
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Re: valve adjustment. help?
If it ran any longer than a few minutes with the intake backfire, I would bet there are chunks of cam metal imbedded in your crank bearings. I would just go ahead and pull the engine and check out the bearings too. The last time I had a cam failure it totally wiped out the crank.
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#16 |
haha, ford guys...
Join Date: Feb 2007
Location: Visalia, CA
Posts: 576
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Re: valve adjustment. help?
your supposed to tighten until the rods stop spinning, then loosen. not tighten.
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#17 |
Registered User
Join Date: Feb 2010
Location: Ft Gibson
Posts: 3
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Re: valve adjustment. help?
I just had a cam failure in a 350. We pulled it out and the bottom of the oil pan was full of metallic oil, So I agree, You can do some quick oil changes and hope for the Best or even better, Yank it out and rebuild it. We replaced ours with a 383 Stroker. Going to redo 350 for an S10 we have.
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#18 |
Registered User
Join Date: Feb 2010
Location: Ft Gibson
Posts: 3
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Re: valve adjustment. help?
Spinem
I've got an old Hanes manual that says to tighten to 0 tolerence then tighten 1/2 turn more. So if you tighten them until You just start to feel friction and tighten them 1/2 more turn they are good. Used this method many times. |
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#19 |
#16876
Join Date: Apr 2005
Location: Auburn WA
Posts: 12,266
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Re: valve adjustment. help?
My most recent cam install. Put in an Isky race cam in my 327. Yes replace your lifter rods timing chain or gears. Make certain that if you decide on a loppier cam that your heads will work with it. This was at initial start up. Not running well in video. Almost forgot, make sure to use cam lube and prime your oil pump before you stab the rotor.
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Posted via Stationary Device '71 Custom Deluxe C-20 402. '67 Buick Special 455. '49 Plymouth Special Deluxe. "I love that old car smell" ![]() Some people are like Slinkies... not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs. Last edited by Sillyoldman; 02-23-2010 at 11:38 PM. |
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#20 |
Registered User
Join Date: Dec 2005
Location: gilbert arizona
Posts: 48
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Re: valve adjustment. help?
Older big blocks are known for eating cams anyway -- 1 tip I got from a guy who knows these engines REAL well says ALWAYS use AC Delco lifters --- no matter what cam installed. Thats what i have in my 454 with ISKY cam now and works fine. Just my 2 cents --
Ditto on the metal in the crank bearings -- when my cam went flat almost 10 years ago (prior to the AC Delco lifters) I ended up spinning a main bearing after replacement. Cheaper to do now than replace a crank etc later. You could always just take a chance -- you may be ok -- but be aware it will be more expensive later! No matter what -- flush it REAL good! |
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