chromaly push rods DON't expand?!

[74baja1915]

i have put some chromoly push rod and a solid rocker shaft with swivel feet adjusters and i was told to set them the push rods just so they spin is this ok to do?

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If its not broke don't fix it, but if it can be made better by all means do it!

[James2]

Yes

[Ryan72]

yep, whoever told you was right on, zero them out to just where they will still spin, but no clearence is notable. chromoly will not expand, so your lash will not change as the motor warms up.

[74baja1915]

cool thanx for the info

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If its not broke don't fix it, but if it can be made better by all means do it!

[Ed Brewer]

That's not exactly true. Chromoly expands with heat, just a slower rate than alumium or magnesium. About half the width of the engine is aluminum or magnesium (heads and case). So the engine as a whole expands at a greater rate than a steel/chromo pushrod. Because of that you can set cold lash at zero, and the lash will increase as the engine heats up. With lash at zero you do need to check it more often because there is no room for error when the engine is cold.

[MASSIVE TYPE IV]

They will expand, but it takes atleast 800 degrees to get them to move a thou

I set mine to zero, just so the pushrod sins, this gives about .004 when hot, according to the temps.

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Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

[Marty]

Yeah but are you running Chomoly head studs or stock? That is a very important thing to consider.

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Marty Staggs
www.staggsracing.com

[Tom Notch]

Chromoly PRs expand at about half the rate of aluminum PRs. At 200 degrees F. stock aluminum expand .016", while Chromoly has expanded .008".

As tested in my oven and using my 12" dial calipers. And physics even agrees.

Your results may vary, but they shouldn't.

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Tom Notch
Tom's Old VW Home

[This message has been edited by Tom Notch (edited 04-17-2002).]

[ANT]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MASSIVE TYPE IV:
<B>They will expand, but it takes atleast 800 degrees to get them to move a thou

I set mine to zero, just so the pushrod sins, this gives about .004 when hot, according to the temps.
</B><HR></BLOCKQUOTE>

Jake, I suggest you send your pushrods to church seeing as how they're sinners. HEATHEN!
-ANT

[mrbajadude]

Jake, Shame on you. If we use your #'s, your pushrods would be 3200 degrees. Are you sure about the 800 degrees???? Ol' John

[Denny Anderson]

I don't understand WHAT the big deal is, all the bickering,Enough. Let me tell you the way
I set them & then you can cut me into pieces.
I set them hot 1st. To .004 or .006 or .008,
& then I check them cold.If it rattles on
start up, I tighten them up,if not ,I'll let it go, I don't know if this is the proper way
or not, but it is the way I've been doing it
for many years & no problem.

[MASSIVE TYPE IV]

I have most of mine made at a local race shop, I just cut them to length. I supply the correct ball ends and go from there..

The ones I have tested, of mine did not expand at all till over 600 degrees, the manufacturer does make a difference. I bought alopt off the shelf, but no longer, as they were very inconsistant and their tip hardness screwed me a few times.



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Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

[petevw]

will this all differ when using chromo headstuds? will pushrod setting/adjusting change?

later,
pete

[Marty]

Yes. The real Chromoly head studs do not expand near as much as stock ones.
I run Chromoly studs and pushrods at .004 and they pretty much stay there. This is a race motor however. Its gets hotter than a street motor but not for vey long.

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Marty Staggs
www.staggsracing.com

[david thomas]

i run a 2276 type 1, with std head studs & have gone through several sets of chromo pushrods. i have dual valve springs in my heads. bugpack ones began making noise after 500 miles, gene berg ones, these were returned because 12 of the ends went flat (don't know whether they were just a bad batch), finally got hold of manton 125000psi rods in cut to length format, and theyre brilliant. i set them at zero lash, but be careful, as it's easy to over adjust, and have a misfire at cold. this dosent seem like a big deal, but as the exhaust valve seats itself, some of the heat generated in the combustion cycle is dissipated into the cylinder head, cooling the valve. if the tappits are over adjusted, the exhaust valve cannot do this. dont know if it would cause any long term problems, but it's something that is good to be aware of.
does anyone know, if chromoly engine studs (good ones) are used, and torqued to std, would there be any benefits? or are they designed for tighter torques?