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Figuring Piston to valve clearance, help......... #1285909 08/15/12 08:07 PM 08/15/12 08:07 PM
Joined: Feb 2005 Posts: 4,884 Michigan MNobody OP master
MNobody OP master Joined: Feb 2005 Posts: 4,884 Michigan	Ok, Ive got a 318 with a .528 solid running .026 lash on all. I'm trying to check the piston/valve clearance without the stock adj.rockers on. with the piston at TDC and the head sitting on the block with no head gasket, moving the valve up and down between the seat and the top of the piston i've got approx .165 of movement and i'm confused, very confused lol. Thanks!

Re: Figuring Piston to valve clearance, help......... [Re: MNobody] #1285910 08/15/12 08:28 PM 08/15/12 08:28 PM
Joined: Aug 2003 Posts: 43,213 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,213 Bend,OR USA	Quote: Ok, Ive got a 318 with a .528 solid running .026 lash on all. I'm trying to check the piston/valve clearance without the stock adj.rockers on. with the piston at TDC and the head sitting on the block with no head gasket, moving the valve up and down between the seat and the top of the piston i've got approx .165 of movement and i'm confused, very confused lol. Thanks! This is sometimes call valve drop clearances, the amount of travel with the valve closed at TDC to the pistons. Now you need to get a pair of solid lifters, it is faster with two and two pushrod that will be at zero lift with your rockers tighten up, or buy, borrow or steal a pair of adjustable rockers and the pushrods that will work on a solid lifter cam with solid lifters Remove the #1 piston to be safe and install all the valve train, just the two rockers, lifters and pushrods for # 1 cylinder, set the valve lash at zero with the cam having both lifters on the heel of the cam, take a dial indicator and measure off of the valve spring retainers, be careful to get the dial indicator stem aligned with the valve angles as close as you can so you don't loose any valve lift, and then rotate the cam over one full revolution while watching the dial indicator to see how much valve lift you get with the #6 piston at 15 degrees before top dead center and until the it(#6 piston) is around 30 ATDC(after top dead center) Confused yet If so PM me for further clarification BTW, you will need a degree wheel with 360 degrees of marking and one with Top Dead Center indicated also , at least one dial indictator with one inch of travel with a magnetic base and a adjustable flexable stem to hold the dial indicator to the mag base You'll also need some stiff wire, I use a coat hangar or a .090 or so piece of welding rod to make a pointer for the degree wheel, nothing to it Like most new things we try , the first time is the worst or hardest I just reread your post, forget the stock rockers go straight to getting the adjustable rocker and correct pushrods Remember the KISS principles, Keep It Simple, Silly don't make it any harder than it allready is Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Figuring Piston to valve clearance, help......... [Re: Cab_Burge] #1285911 08/15/12 09:02 PM 08/15/12 09:02 PM
Joined: Feb 2005 Posts: 4,884 Michigan MNobody OP master
MNobody OP master Joined: Feb 2005 Posts: 4,884 Michigan	Thanks Guy's, the short block is still assembled in the car. I've got Ross 10:1 's w/valve reliefs, .090 down in the Ho and i'd like to shave these 72cc chambered 360 j-heads down to gain back some compression. Think i can take take .040 off them and use a.025 head gasket safely? I don't have a dial indicator, cam and lifters are still in the block i measured .352 lift at the solid lfter x 1.5 =.528 but then i got lost....

Re: Figuring Piston to valve clearance, help......... [Re: MNobody] #1285912 08/15/12 10:05 PM 08/15/12 10:05 PM
Joined: Jul 2003 Posts: 6,167 Maryland GO_Fish master
GO_Fish master Joined: Jul 2003 Posts: 6,167 Maryland	Your heads are off. I just put playdoh on top of a piston, bolt the head on loosely, get your lifters set where you want, then slowly turn the motor over by hand. Pop the head back off and take a utility knife and slice a cross section of clay across the middle of each valve. You will be able to measure your actual clearance, then add for your compressed head gasket and subtract for your milling, then you have your number. You could do this on multiple cylinders for a higher comfort level if you want. Scott B. "I'm a self-made man... I started with nothing, and I still have most of it!" 68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph 69 340 GTS stock 14.18@ 95.60 mph 01 5.9L Ram 1500 Quad Cab 4x4 01 3.5L 300M 16.23@ 86.97 mph

Re: Figuring Piston to valve clearance, help......... [Re: GO_Fish] #1285913 08/15/12 11:18 PM 08/15/12 11:18 PM
Joined: Feb 2005 Posts: 4,884 Michigan MNobody OP master
MNobody OP master Joined: Feb 2005 Posts: 4,884 Michigan	Thank you! turns out with the gasket in place .046, i only have about .015-.020 on the intake and about .050 on the exhaust. Taking .040 of the surface could have been a problem....

Re: Figuring Piston to valve clearance, help......... [Re: MNobody] #1285914 08/15/12 11:45 PM 08/15/12 11:45 PM
Joined: Nov 2004 Posts: 1,708 S. Il. U.S.A. 5spdcuda top fuel
5spdcuda top fuel Joined: Nov 2004 Posts: 1,708 S. Il. U.S.A.	Ideally you should have at least .100 on the intakes and .125 on the exhausts. You can get away with less, but if you get any valve float it may not be very pretty.

Re: Figuring Piston to valve clearance, help......... [Re: 5spdcuda] #1285915 08/15/12 11:58 PM 08/15/12 11:58 PM
Joined: Jan 2003 Posts: 27,421 Balt. Md 3 383man Too Many Posts
383man Too Many Posts 3 Joined: Jan 2003 Posts: 27,421 Balt. Md	The clay will work fine. But you have to have the timing chain on and in time and the valves adjusted. You will want to check both the intake and exh all thru the overlap period the exh/int stroke. As long as you turn the eng over a full 360 degrees you should get a reading. I use a light spring under the valves when I do it as that way if I have one that I feel is close I will bring it up to that spot and then put a dail indicator on the valve and push the valve down until it hits the piston to get a very accurate check. Ron

Re: Figuring Piston to valve clearance, help......... [Re: MNobody] #1285916 08/16/12 12:18 AM 08/16/12 12:18 AM
Joined: Jan 2003 Posts: 75,043 U.S.S.A. JohnRR I Win
JohnRR I Win Joined: Jan 2003 Posts: 75,043 U.S.S.A.	Quote: Thank you! turns out with the gasket in place .046, i only have about .015-.020 on the intake and about .050 on the exhaust. Taking .040 of the surface could have been a problem.... looks like you don't have enough as it is .

Re: Figuring Piston to valve clearance, help......... [Re: JohnRR] #1285917 08/17/12 01:32 AM 08/17/12 01:32 AM
Joined: Feb 2005 Posts: 4,884 Michigan MNobody OP master
MNobody OP master Joined: Feb 2005 Posts: 4,884 Michigan	Why is that? Oh the head gasket measures .050 i measured in a bad spot before. Fixed a couple valves and lapped them all in, gonna put her back together with the same kind of gasket's it had.

Re: Figuring Piston to valve clearance, help......... [Re: 5spdcuda] #1285918 08/17/12 09:47 PM 08/17/12 09:47 PM
Joined: Jul 2003 Posts: 6,167 Maryland GO_Fish master
GO_Fish master Joined: Jul 2003 Posts: 6,167 Maryland	Quote: Ideally you should have at least .100 on the intakes and .125 on the exhausts. You can get away with less, but if you get any valve float it may not be very pretty. Scott B. "I'm a self-made man... I started with nothing, and I still have most of it!" 68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph 69 340 GTS stock 14.18@ 95.60 mph 01 5.9L Ram 1500 Quad Cab 4x4 01 3.5L 300M 16.23@ 86.97 mph

Re: Figuring Piston to valve clearance, help......... [Re: MNobody] #1285919 08/18/12 10:04 AM 08/18/12 10:04 AM
Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O 70Cuda383 Too Many Posts
70Cuda383 Too Many Posts Joined: Oct 2003 Posts: 21,345 Marysville, O-H-I-O	Quote: Why is that? Oh the head gasket measures .050 i measured in a bad spot before. Fixed a couple valves and lapped them all in, gonna put her back together with the same kind of gasket's it had. with the gasket in place, you had .020 of intake valve clearance and .050 of exhaust clearance? or was that WITHOUT the gasket in place, you had .020 and .050? your post said "with gasket in place" and even if you meant "without" those numbers are pretty dang tight! Photobucket sucks

Re: Figuring Piston to valve clearance, help......... [Re: 70Cuda383] #1285920 08/18/12 02:05 PM 08/18/12 02:05 PM
Joined: Feb 2005 Posts: 4,884 Michigan MNobody OP master
MNobody OP master Joined: Feb 2005 Posts: 4,884 Michigan	Must be the reason they went with a mechanical cam, I can't believe this thing run's as good as it did with 8.17 comp and i won't even get into what i found with the heads. Needless to say they are getting the ports cleaned up and i lapped the valves, new heads in the near future. Gonna put her back together with the same thickness gaskets as it had with hopefully no surfacing. Guy told me he ran .026 lash on all the valves, i'll loosen them up to .028 just for grins and giggles. I look at it this way, they beat the crap outta the 318 at the track trapping at 7,000. I beat on it every time i take her out, and the only issue i found so far is bad workmanship done on the heads with leaky valves.

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