camshaft change

astikhossw · 10-09-2012, 11:10 AM

is it necessary to change the pushrods if going a little higher on the lift say about .075 int and .060 exh.or just change the height of the shims on a jesel rocker stand.

Marine One · 10-10-2012, 06:07 AM

Neither. Why would you want to install a bigger bump stick, then try to eliminate the extra lift?

You would not need to change pushrods unless the diameter of the base circle changed (base circle, not lobe).

By raising the base where the rocker sits, you affect how the rocker contacts the top of he valve stem, which impacts valvetrane geometry...good or bad depending on where everything was at before you started changing things.

Mike Taylor 3601 · 10-10-2012, 10:23 AM

Stand height is correct now? adjusters can be adjusted from bottomed against rocker to 2 turns out,if you can adjust valves with adjusters in that range then your pushrods will work if not then you'll need different length.
If you are'nt sure about stand height I would check using tool Jesel used to supply with rocker kit,it is usaully close.

You can measure base circle on cams to compare.
Mike Taylor3601

10-09-2012, 11:10 AM	#1
astikhossw Member Join Date: Jul 2008 Location: moreno valley Ca Posts: 266 Likes: 2 Liked 20 Times in 9 Posts	camshaft change is it necessary to change the pushrods if going a little higher on the lift say about .075 int and .060 exh.or just change the height of the shims on a jesel rocker stand.

10-10-2012, 06:07 AM	#2
Marine One Junior Member Join Date: Mar 2010 Location: Indiana Posts: 69 Likes: 1 Liked 0 Times in 0 Posts	Re: camshaft change Neither. Why would you want to install a bigger bump stick, then try to eliminate the extra lift? You would not need to change pushrods unless the diameter of the base circle changed (base circle, not lobe). By raising the base where the rocker sits, you affect how the rocker contacts the top of he valve stem, which impacts valvetrane geometry...good or bad depending on where everything was at before you started changing things. __________________ Chad Sheets \| STK 319 \| 10.69 \| 1.39

10-10-2012, 10:23 AM	#3
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,364 Likes: 342 Liked 281 Times in 97 Posts	Re: camshaft change Stand height is correct now? adjusters can be adjusted from bottomed against rocker to 2 turns out,if you can adjust valves with adjusters in that range then your pushrods will work if not then you'll need different length. If you are'nt sure about stand height I would check using tool Jesel used to supply with rocker kit,it is usaully close. You can measure base circle on cams to compare. Mike Taylor3601