DriveATransAm

i have a .563 lift cam and heads are 0.050 milled. how much p/v clearance should there be at TDC?

RyanJ

i thought i read .090. cant remember

Jason99T/A

iTrader: (21)

Shoot for a minimum of .080" on the intake and .100" on the exhaust.

<small>[ July 24, 2002, 12:04 AM: Message edited by: Jason99T/A ]</small>

DriveATransAm

i think you mean 0.08 ?

i have a about .20 for the closest one <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> .

SStrokerAce

iTrader: (2)

yeah you mean .080 Intake and .100 exh

DriveATransAm

SWEET. so im good to go then. who says you cant use stock length pushrods on 0.050 milled heads <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Jason99T/A

iTrader: (21)

corrected my numbers... I guess I should re-read my posts before hitting reply. <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

DriveATransAm

im really amazed at how you can use stock length pushrods with that much off the heads though. doesnt comp say to use stock rods if you have stock heads anyways?

i did get around to torqing one of the heads down though. it got late and i got tired so im stopping for the night <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

should be done soon hopefully.

VAP

STOP !!!!!! have i missed the boat here or what - you don't check piston to valve @ tdc you have to check whilst rotating the motor - the valves actually get the closest anywhere between 8- 12 degrees ( depending on cam duration/ lobe centreline etc etc ) before and after tdc depending whether your checking the intake or the exhaust........
The piston chases the exh valve & the inlet valve chases the piston....
You can check with plasticine ( my non preferred way)
Or assemble the head with no springs fitted and just 2 type mushroom seals on so as the valve ( 1 seal per valve ) -can not fall into the cylinder but can fall as far down as where the mushroom seal is - I usually only push on the seals just under the collet groove. Hold the valves up by hand @ tdc on firing stroke of that cylinder adjust the tappets so as you have zero clearance BUT no preload and then push that valve down all the way whilst holding up the rocker, then slowly rotate the motor 360 degrees (whilst still holding up the rocker )and you'll see the valve and rocker chasing each other around tdc (on the overlap tdc )- when you see the miminum clearance by eye, slip in some feeler gauges and measure you piston to valve clearance - being sure that you are not applying lifter preload whilst checking the clearance and hence getting false figures etc. Once you have found this clearance be sure to rotate the motor 2 complete revolutions being sure it doesn't get tight anywhere else or moreso make sure you got the valves on the overlap of the cam and not the firing stroke ......... Do it everyday and can do it with my eyes closed but you know what, I've always been **** and trying to explain things to people ... SORRY

Just use the old not so trusty plasticine method..

Hope I've helped rather than confuse you ...

<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

VAP

BY the way pushrod length doesn't do anything in regards to <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> pushrod length or rocker geometry....
Are you trying to check piston to valve or lifter preload???????

<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

DriveATransAm

i didnt understand a damn thing you just wrote <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> maybe its too early.

im was talking about piston to valve clearance though <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> .

i talked to one of the site sponsers before people got around to responding and he said that i should be good to go too. not really sure what youre getting at <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Reckless

iTrader: (9)

VAP....I started feeling queasy about half way through that paragraph <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

My heads are also milled .050 and I use the 7.350" pushrods. You should also to ensure more correct valvetrain geometry. Not sure what the effect is on PTV clearance though?

I am going back to flat top pistons soon as well, so I have been trying to discern the max lift/duration for my new cam purchase.

DriveATransAm

well, how much clearance is stock?

Pro Stock John

iTrader: (34)

You should need shorter pushrods.

DriveATransAm

well, i tested the other head with playdoh today (was using plumbers putty before). i put a little over half an inch piece in. well, lets just say playdoh blew out the sparkplug hole! haha. i dont think i got enough clay in when i first tested it and i didnt get a whole impression of the valve. lets just say ill be using the shorter ones, haha.

Pro Stock John

iTrader: (34)

What you really need to do is measure lifter preload. With the stock 7.450's I think you will be .050 too much might be like .100 lifter preload.

Jason99T/A

iTrader: (21)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>What you really need to do is measure lifter preload. With the stock 7.450's I think you will be .050 too much might be like .100 lifter preload.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The stock pushrods are actually 7.400".

DriveATransAm

well, the heads are on, water pump is on, headers are on, intake is on, valvetrain is on (with the 7.35s). if something breaks- im getting a stroker. only thing left are radiator and coil packs <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> . im giddy like a school girl <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Dom

iTrader: (2)

You're one talented **** when it comes to photoshop, but checking clearance is another thing.

DriveATransAm

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Dom:
<strong>You're one talented **** when it comes to photoshop, but checking clearance is another thing.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

i dont even know how to use photoshop. thanks for the words of the wise though...not sure if that was a compliment or insult though. ill just take it as a compliment though and not get mad <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

tomorrow= <img border="0" alt="[Firebird]" title="" src="graemlins/formula.gif" />