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generalities about valvle lash and its relation with temp
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Author:  argentina-slantsixer [ Sat Dec 18, 2004 9:07 pm ]
Post subject:  generalities about valvle lash and its relation with temp
hey there

I wanna know if higer lash on ex valvles produces more or less heat.

Also I'd like to double check something: I always believed that the more initial timing you have, the less engine temp works at, but at some post the other day some guy told me that too much advance could produce overheating... is that true?

thanks, and merry xmas and happy new year.

juan
Author:  Slant6Ram [ Mon Dec 20, 2004 9:07 am ]
Post subject:  generic answers
Don't know about the valve lash question.

I expect that on the timing question, too much advance is "too much too early" or "too much total". Both conditions can cause preignition and excessive heat generation.

Initial timing, when when coupled with a properly recurved distributor advance can be set (in my experience) to 10 degrees and possibly more without causing excessive heat problems. Keep in mind, that the properly recurved distributor is required to control the early and total advance problems.
Author:  Doctor Dodge [ Tue Dec 21, 2004 10:50 am ]
Post subject: 
The more lash clearance you have, the longer the valve will be on the seat and the "seat time" is when the valve is cooled by the water jacketed cylinder head. This is especially important with the exhaust valves, which run red hot.
DD
Author:  argentina-slantsixer [ Tue Dec 21, 2004 1:07 pm ]
Post subject: 
Thanks you guys.

Doc, thanks for the ex note. I gotta say that I'm not happy with my grinder's advice on lash setting so I was wondering (and actually I started by increasing ex to almost stock and intake just a li'l) how could I operate over ex temp. also, what'd be your input on the timing "affaire" ;) ? I'm talking about 14 initial, not 20°. Does that produce overheat?

Slant6Ram, thanks. I'm not way out of initial timing, especially since I've recurved and bench tested my dist. It has 18° of total mech advance and it gives it full by ~ @2300 rpm. Not happy with my vac pod tho. I'm getting a crappy mileage (13 at the city, 20 when cruisin) but my foot is heavy.
Author:  Doctor Dodge [ Thu Dec 23, 2004 11:06 am ]
Post subject: 
Extra initial timing should not effect engine temp., the burn at idle is pretty cool compared to an engine under load.

I find that if the initial timing is set to far advanced that the idle will get rough. You also have to avoid detonation because this increases engine temps and kills performance.

Always keep the total advance around 30 degrees for the best WOT performance. (each engine is a little different so this is something you need to try some different settings to find the best total)
DD
Author:  argentina-slantsixer [ Thu Dec 23, 2004 1:29 pm ]
Post subject: 
thanx doc

merry xmas and happy new year.

Thanks for yyour advice, I was kinda worriend 'cuz I have to recurve another dist for having like 15 or 16 total mec advance plus another 15 initial and the pod.... maybe my one barrel is way too li'l to feed my cam and 0.20 overbore and shaved head and block with steel gasket setup....

I "invented" a new style eccentric post distributor recurving tool by carving a "V" into a screwdriver. It allows me to work on those posts with mag pickup plate bolted... I'm gonna shot some pix as soon as I get back home.

My best wishes to all you guys.
Juan, from way down argentina.
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