Re: How much can you tighten Valve Lash?
[Re: GwaiiEagle]
#1222168
04/25/12 10:51 PM
04/25/12 10:51 PM
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Joined: Aug 2003
Posts: 43,163 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,163
Bend,OR USA
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Quote:
Magnum 282 solid, 282 adv, 236 at 50, .495 stock lift, .528 with my 1.6 rocker arms.
It is said that you can tighten lash to see if the engine likes it.
Question is how much can you safely tighten it? Magnum Cams must have a mild ramp speed.
I have been told and used the 25% rule, if it is suppose to be set at .024 hot then .006 tighter and no more than .004 looser is what I try. Same thing if it is a tight lash cam, .016 hot then tighten up to .012 max and to .020 looser max
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: How much can you tighten Valve Lash?
[Re: Mr.Yuck]
#1222172
05/04/12 05:50 PM
05/04/12 05:50 PM
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Joined: Apr 2004
Posts: 329 Frederick, MD
moparguy1967
enthusiast
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enthusiast
Joined: Apr 2004
Posts: 329
Frederick, MD
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Quote:
??? I ran a MP 528 solid at 22-24 (cold). It seemed to run better than the factory recommened 28-32
Not to hi jack this tread, but Im running the 284/528 solid in my car. Do you feel that running it at 22-24 will hurt the valve train at all on a street car?? Thanks
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Re: How much can you tighten Valve Lash?
[Re: moparguy1967]
#1222173
05/04/12 06:11 PM
05/04/12 06:11 PM
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Joined: Oct 2007
Posts: 288 Birmingham, England
Mick70RR
enthusiast
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enthusiast
Joined: Oct 2007
Posts: 288
Birmingham, England
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I run the MP 528 cam and set the lash 20/22 cold. I run Stealth heads so the lash gets bigger as the engine warms up. I don't think I'd set the lash that tight with iron heads because the lash gets smaller with heat. 28/32 cold with iron heads would be around 26/30 with iron heads once it's warm and that's about what I have when the ally heads heat up.
1970 Road Runner
505 cid
MCH CNC ported Stealth heads
MP 528 camshaft
4 speed
GV overdrive
11.98 @ 117 on street treads
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Re: How much can you tighten Valve Lash?
[Re: GwaiiEagle]
#1222174
05/04/12 09:25 PM
05/04/12 09:25 PM
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Joined: Jun 2008
Posts: 3,916 usa
lewtot184
master
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master
Joined: Jun 2008
Posts: 3,916
usa
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Quote:
Magnum 282 solid, 282 adv, 236 at 50, .495 stock lift, .528 with my 1.6 rocker arms.
It is said that you can tighten lash to see if the engine likes it.
Question is how much can you safely tighten it? Magnum Cams must have a mild ramp speed.
the lash on this cam can be varied between .015"-.030" per comp cams. i would use .016" hot as the minimum with a 1.6 rocker.
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Re: How much can you tighten Valve Lash?
[Re: moparguy1967]
#1222175
05/04/12 10:42 PM
05/04/12 10:42 PM
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Joined: Jan 2003
Posts: 24,562 Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Quote:
??? I ran a MP 528 solid at 22-24 (cold). It seemed to run better than the factory recommened 28-32
Not to hi jack this tread, but Im running the 284/528 solid in my car. Do you feel that running it at 22-24 will hurt the valve train at all on a street car?? Thanks
I had iron heads and it seemed to work for me. You can always try 24/28 for starters
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Re: How much can you tighten Valve Lash?
[Re: Stanton]
#1222177
05/05/12 12:56 AM
05/05/12 12:56 AM
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Anonymous
Unregistered
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Anonymous
Unregistered
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I have always thought "tight lash" cams were just another way to claim better numbers under the curve. Another cam sales device for sure! ( or every cam on the planet would be one!) I have seen race engines run and sound just fine but be much slower( several tenths) when lash was too tight--as in the valves never really close and "seal in" that lick. You have to get enough lash so that they really have a chance to close at the RPM you are racing at. I would bet my shop that on a dyno you would see very little diff going with more lash but too little can kill power. It is all bout RPM as well--a street engine is not the same as a unit buzzing 7500 RPM--Component weight plays even more as RPM goes up--Swapping to Titanium retainers can often make it feel like you changed engines in a drag car--If you were short on installed height like some small blocks even more so. It is a balancing act and lash plays a very small part as long as you have enough. There is no way to explain how much you can learn on a dyno in a year--it will dispell lots of BS "conventional wisdom" in a HURRY. Light weight valvetrain GOOD, Belt Drives GOOD, stiff pushrods GOOD, enough spring pressure to control it all GOOD Chasing valve lash all over the place--a waste of time IMO. I have seen Bob Reed lash a Hemi in staging so fast it would make your head spin and he did NOT get them within a few thou--he lashed 'em and raced 'em--in other words--made darn sure it HAD some then went to it!!! Ya'll should to--and...in a drag engine do intake and Ex the same--it is EASIER and who thinks that in 6-10 seconds an ex valve will be hot enough to change the lash enough to make one millionth of a second diff?
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