dannyz

Got a GM Hotcam that I'm gonna shove into my engine.
I was going to reuse my stock pushrods, but my friend told me that was a no-no.
He says to get a set of stock length chrome moly pushrods to play it safe.
He seems to know what he's talking about, what do you guys think?
I was hoping the stock ones would work, since the hotcam uses ls-6 springs, but if you guys say " get the chrome moly's", thats what I'll do.

Tainted

iTrader: (9)

chromeoly, maybe not. hardened, sure why not.

I think a hardened pushrod will do its job just fine for you. your friend is sorta right, its always good to go with a stronger pushrod, but the chromeoly isnt needed unless you really wanna spin high.

Die Grinder

You can't have too strong of a pushrod. Go to Manton pushrods site and read Terry Manton's article on column theory. A hardened pushrod is only required if you're using guide plates or a head that has guides machined in like production small block chevy before guided rockers.

Medic/Z28

iTrader: (9)

I agree with Tainted. Look at my sig. I have the same cam.

PREDATOR-Z

GM hotcam will run with no issues on stock p-rods if they are straight to beguin with. However it does have a smaller base circle than stock cam so it would benefit from the AOL added length of the aftermarket. (there is a difference between guage length and AOL on aftermarket)

dannyz

Thakyou guys.

Andy1

How much smaller is the base circle diameter than the stock cam? Just to confirm: Hot Cam base circle diamter difference/2 = additional length required over the stock push rod.

I thought the GM Hot Cam had the same base circle diameter as the stock cam.
Thanks,
Andy1

Andy1

Anyone?

Thanks,
Andy1

EastTnZ28

iTrader: (20)

Pushrods are cheap insurance. Im the type that would use new pushrods and new lifters with a new cam and not think twice about it. .02

NaturalMystic831

sorry to jump in but do all chevy small blocks (especially LS1) use the same length rods?

Old SStroker

We have a variety of opinions here. I think that the OP should listen to EastTNZ28 and Die Grinder. Their posts make a lot of sense. A stiffer pushrod helps the cam produce the designed valve motion and improves valvetrain stability especially at the higher revs we all tend to exploit with a cam change.

Base circles get smaller with increased lift because the nose or highest lift point on the lobe can't be any taller than the bearing journals, and the lobe lift comes from the radius of the journal minus the radius of the base circle. Well, the nose of the lobes as a tad under the radius of the journal so the lobes don't hit the bearings during install.

Someone should expound on how smaller base circle lobes increase valvetrain loads. I'm not a cam guru, but I did have dinner with one last night.

Merry Christmas to all.

Jon

Andy1

Discussion on smaller base circles is fine, but the GM Hot Cam has the same lift as a stock cam and I read for the first time in this thread that its' base circle diameter is smaller. I'm not contesting that perhaps it is. I've read nothing from GM recommending a longer push rod when doing this install, therefore my original question:

"How much smaller is the base circle diameter than the stock cam? Just to confirm: Hot Cam base circle diamter difference/2 = additional length required over the stock push rod.

I thought the GM Hot Cam had the same base circle diameter as the stock cam."


Andy1

silverta00

iTrader: (3)

I had a 2000 Trans Am and began to lose power around 50,000 miles. I was told by several people that the stock pushrods were weak and might want to put hardened ones in. I decided to give it a try and ended having 9 bent pushrods. Some just barely and some very noticable. And I never even put a cam in that car. It would probaly be a good investment to put new ones in to avoid problems later.

jakebdb56

iTrader: (25)

Sorry to kinda dig up an older thread, BUT I had the same question about the base circle as well. GMPP does a great job at listing the duration, lift, and LSA but there aren't any other specs out there. My theory is that if they sell the "GMPP LS1 Hot Cam Kit" that comes with just blue LS6 springs you won't have any problems swapping into a stock motor. I of course went ahead and opted for some comp cam magnum pushrods for the ease of mind factor, but I'm not totally sure that you have to get different pushrods. Anyways, my hotcam should go in next weekend so we'll see what kind of numbers it makes. Right now I'm sitting at 285rwhp/300rwtq

regorih383

iTrader: (21)

stock push rods are good

1970judge

iTrader: (12)

It is best to run a hardened pushrod with a new cam! In some cases not necessary but in most all cases, worth it.

-Marcus