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School me on Valve Lash... A couple of questions. #1096570 10/17/11 09:34 PM 10/17/11 09:34 PM
Joined: Jan 2003 Posts: 2,309 Tomorrow. D Damned67 OP top fuel
Damned67 OP top fuel D Joined: Jan 2003 Posts: 2,309 Tomorrow.	Hi All, I'm new to the solid (lifter) cam scene, always run hydraulic in the past. I just did the lash on the weekend, and have a bunch of questions. 1) What's your 'rule of thumb' on how often the lash should be set/checked? 2) Spark plugs in or out when turning the engine by hand? 3) What effect does having the lash looser or tighter than the cam card specs have? 4) If using lash caps, does the lash setting need to be altered from that on the cam card? 5) I followed the Mopar Performance Valve Lash chart (turning the engine 90 degrees each time). Now, if I'm a touch off on the 90 degrees (although my damper is marked every 90, so I can get it nice and close), it shouldn't matter too much as the lifter/pushrod/valve will be on the base circle/heel of the lobe, right? Sorry for the seemingly simple questions.

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096571 10/17/11 09:40 PM 10/17/11 09:40 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	(1) No opinion (2) in if your a weight lifter, out if not (3) not sure (4) no but it MAY alter wipe pattern and or pushrod length needed but that small of a height change may be insignificant (others will chime in on that) (5) right. PS sometimes simple Q's are all we can handle live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096572 10/17/11 10:42 PM 10/17/11 10:42 PM
Joined: Jun 2008 Posts: 3,916 usa L lewtot184 master
lewtot184 master L Joined: Jun 2008 Posts: 3,916 usa	1. usually once a year. i don't have lash issues 2.plugs out 3.looser reduces seat timing, tighter increases seat timing 4.lash caps can effect rocker geometry but don't effect lash settings 5.may depend. a longer duration cam will be more critical than a shorter. for me, rollers are a little testyer than flats. i always double check settings. i don't use 90 degree method.

Re: School me on Valve Lash... A couple of questions. [Re: RapidRobert] #1096573 10/17/11 10:58 PM 10/17/11 10:58 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	On OE flat tappet engines the service interval for valve lash was pretty long - 12k miles or something like that. On a high po build with higher loads that might be a little long. On mine, I checked after break in to make sure nothing was moving or amiss. It was fine. Then I checked after about 2,000 miles. Little to no adjustment required. All was well. Now I check every 3-5k miles - mostly a precuation. Still little adjustment required. If I was racking up the miles I'd probably go 10k between adjustments unless I was really hammering it. I just worked up to it to make sure everything was solid and stable. If you are turning by hand, pull the plugs. I've done it with the MOPAR chart but got away from it. Now I use a remote starter to bump it over. When the intake is "significantly" depressed I check the exhaust and vica-versa. I do one cylinder at a time. I find this faster and easier than the chart. If you are setting lash hot pulling the plugs on a hot engine is no fun and gives it time to cool down. I've done mine both hot and cold to confirm the "rule of thumb" that hot lash is 4-5 000's more than cold lash on an aluminum headed iron block engine. Now I usually just do them cold and set lash 5 000's tighter than spec. That way they are at spec when hot. Setting lash tighter than spec makes the cam act like a bigger longer duration cam. Looser than spec makes the cam act smaller. Cams and adjustment tecniques vary, but most folks would say playing with the lash spec plus or minus 5 000's is probably OK. Going outside spec beyond this risks getting into problems with opening and closing ramps.

Re: School me on Valve Lash... A couple of questions. [Re: ahy] #1096574 10/18/11 10:51 AM 10/18/11 10:51 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Quote: I've done mine both hot and cold to confirm the "rule of thumb" that hot lash is 4-5 000's more than cold lash on an aluminum headed iron block engine. Now I usually just do them cold and set lash 5 000's tighter than spec. That way they are at spec when hot. Ahy to clarify this for me you set the cold lash 5 thou LESS than the specified cold spec? The first sentence was confusing me "hot lash is 4-5 thou GREATER than cold lash" as I thought the hot would be less. Am I backwards here? live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: RapidRobert] #1096575 10/18/11 06:03 PM 10/18/11 06:03 PM
Joined: Apr 2010 Posts: 4,154 bethlehem pa M mikemee1331 master
mikemee1331 master M Joined: Apr 2010 Posts: 4,154 bethlehem pa	Quote: (1) No opinion (2) in if your a weight lifter, out if not (3) not sure (4) no but it MAY alter wipe pattern and or pushrod length needed but that small of a height change may be insignificant (others will chime in on that) (5) right. PS sometimes simple Q's are all we can handle a little more info would also help with getting things answered. street car, drag, 6-banger, what are we working on? the tolerances can be different.

Re: School me on Valve Lash... A couple of questions. [Re: RapidRobert] #1096576 10/18/11 08:27 PM 10/18/11 08:27 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	Quote: Quote: I've done mine both hot and cold to confirm the "rule of thumb" that hot lash is 4-5 000's more than cold lash on an aluminum headed iron block engine. Now I usually just do them cold and set lash 5 000's tighter than spec. That way they are at spec when hot. Ahy to clarify this for me you set the cold lash 5 thou LESS than the specified cold spec? The first sentence was confusing me "hot lash is 4-5 thou GREATER than cold lash" as I thought the hot would be less. Am I backwards here? You got it. Set cold lash 4-5 000's less than what you want when hot. This is a rule of thumb for iron block/aluminum head. Lash increases with heat because the aluminum head expands faster than the steel pushrods. Its a good idea to do your combo both hot and cold to check the "rule of thumb" before depending on it 100% since its hot lash that you really want to control.

Re: School me on Valve Lash... A couple of questions. [Re: ahy] #1096577 10/18/11 09:15 PM 10/18/11 09:15 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Quote: Lash increases with heat Now it makes sense. Thank you Last edited by RapidRobert; 10/18/11 09:30 PM. live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: RapidRobert] #1096578 10/18/11 09:44 PM 10/18/11 09:44 PM
Joined: Jan 2003 Posts: 2,309 Tomorrow. D Damned67 OP top fuel
Damned67 OP top fuel D Joined: Jan 2003 Posts: 2,309 Tomorrow.	Thanks guys! To the poster requesting info, it's a 'street' 505" with Eddy heads on an iron block. More Q's: a) How 'hot' does the engine need to be do a 'hot' lash? I warmed the car up to 180, then set about pulling plugs, valve covers, then setting the lash. All up it probably took me ~45min, but all along I would touch a head, and it continued to hold enough heat to feel like it was going to burn me. b) One that's going to be really tough to answer, how 'snug' should the feeler gauge be between the rocker tip and the valve? Cheers!

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096579 10/18/11 09:55 PM 10/18/11 09:55 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Quote: how 'snug' should the feeler gauge be between the rocker tip and the valve? Cheers! If the spec is for example .020" you want a .021" blade to have a slight drag and a .019" blade to have no drag. Held parallel of course. this will get you to within .001" live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096580 10/18/11 10:12 PM 10/18/11 10:12 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.	How hot is hot? Well an engine dosen't really get to full operating temp until the oil is up to temp. Water heats up faster. You can get a good sense of oil temp from watching the oil pressure gauge if you don't have an oil temp gauge. When the oil pressure stabilizes at normal running pressure the engine is pretty well up to normal operating temp. When allowing for setting lash cold Crane recommends the following: iron block and heads add .002 eg. hot lash=.028, set at .030. Iron block, alum heads subtract .006 eg. hot lash = .028, set at .022. Alum block and heads subtract .012 eg. hot lash .028, set at .016. Added bit of trivia, most adjusters are 3/8 in. fine thread. This means that one full turn is equal to just under .042. 3/8 fine thread has 24 threads to the inch. By definition there are 1000 thousands to the inch. 1000 divided by 24 = 41.666. If you have roller tipped rockers getting the right feel is tricky. Try moving the blade sideways. Better yet get a go, no go feeler gauge. They don't cost all that much and are easier to use. Last edited by 5spdcuda; 10/18/11 10:18 PM.

Re: School me on Valve Lash... A couple of questions. [Re: 5spdcuda] #1096581 10/18/11 10:19 PM 10/18/11 10:19 PM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Quote: Added bit of trivia, most adjusters are 3/8 in. fine thread. This means that one full turn is equal to just under .042. 3/8 fine thread has 24 threads to the inch. By definition there are 1000 thousands to the inch. 1000 divided by 24 = 41.666 good tech live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: RapidRobert] #1096582 10/18/11 10:47 PM 10/18/11 10:47 PM
Joined: Oct 2005 Posts: 4,956 WI Dcuda69 master
Dcuda69 master Joined: Oct 2005 Posts: 4,956 WI	Quote: Quote: how 'snug' should the feeler gauge be between the rocker tip and the valve? Cheers! If the spec is for example .020" you want a .021" blade to have a slight drag and a .019" blade to have no drag. Held parallel of course. this will get you to within .001" I would prefer a .020 to have a slight drag, a .021 to not fit and a .019 to be loose.

Re: School me on Valve Lash... A couple of questions. [Re: Dcuda69] #1096583 10/18/11 11:00 PM 10/18/11 11:00 PM
Joined: Feb 2005 Posts: 4,318 Prospect, PA BSB67 master
BSB67 master Joined: Feb 2005 Posts: 4,318 Prospect, PA	Quote: Quote: Quote: how 'snug' should the feeler gauge be between the rocker tip and the valve? Cheers! If the spec is for example .020" you want a .021" blade to have a slight drag and a .019" blade to have no drag. Held parallel of course. this will get you to within .001" I would prefer a .020 to have a slight drag, a .021 to not fit and a .019 to be loose. It is more like .020" will be very snug, and .021" will not fit.

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096584 10/19/11 02:12 AM 10/19/11 02:12 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	Quote: One that's going to be really tough to answer, how 'snug' should the feeler gauge be between the rocker tip and the valve? Cheers! Any thoughts Damned67 . You were right it wasn't going to be easy live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: RapidRobert] #1096585 10/19/11 02:18 AM 10/19/11 02:18 AM
Joined: Jan 2003 Posts: 2,309 Tomorrow. D Damned67 OP top fuel
Damned67 OP top fuel D Joined: Jan 2003 Posts: 2,309 Tomorrow.	Quote: Quote: One that's going to be really tough to answer, how 'snug' should the feeler gauge be between the rocker tip and the valve? Cheers! Any thoughts Damned67 . You were right it wasn't going to be easy I went with 'slight drag' on the specified blade. I'm going to go back in when I next get a chance and compare my lash setting against the blades that are next size up + down. Cheers!

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096586 10/19/11 02:34 AM 10/19/11 02:34 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	I'm gonna put a dial indicator inline vertical on top of it & find out which one is the best (like the old P&G hand held valve gapper that had a dial indicator dial built in) live every 24 hour block of time like it's your last day on earth

Re: School me on Valve Lash... A couple of questions. [Re: Damned67] #1096587 10/19/11 02:38 AM 10/19/11 02:38 AM
Joined: Feb 2004 Posts: 4,501 Gainesville,FL G goldmember master
goldmember master G Joined: Feb 2004 Posts: 4,501 Gainesville,FL	5spdcuda and bsb67 are right on. Don't waste too much time with this. Just be consistant and you'll be good. It's very simple.

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