Bent and grinding pushrods
6th Gear Member
Joined: Apr 2007
Posts: 10,468
From: California
KEEP THE LIFTERS IN ORDER!!!
They don't interchange to different cam lobes, and no, you can't just replace lifters on a flat tappet cam, the lobes and lifters wear together. If they're worn properly the lifters should be mostly shiny on the bottom with a slight bullseye pattern, and no scuffing or pitting. And they're actually slightly convex, though they make appear flat to the eye, if they look concave at all, they're toast.
Edit: Also good point about the rockers.....with the pushrods wearing like that, the rocker alignment was all over the place, so the roller tip and/or bearings in them could be shot.
They don't interchange to different cam lobes, and no, you can't just replace lifters on a flat tappet cam, the lobes and lifters wear together. If they're worn properly the lifters should be mostly shiny on the bottom with a slight bullseye pattern, and no scuffing or pitting. And they're actually slightly convex, though they make appear flat to the eye, if they look concave at all, they're toast.
Edit: Also good point about the rockers.....with the pushrods wearing like that, the rocker alignment was all over the place, so the roller tip and/or bearings in them could be shot.
Thread Starter
Joined: Nov 2010
Posts: 12
From: AR/CO
the lifters are really as simple as remove old and drop new in. the more complicated part is how to adjust the rockers (so to say play). too loose: tapping, to tight: cam and lifters dead.
to check on the lifters, they should be 100% flat at the bottom (the part that sits on the cam). If there are deep marks in eat or parts eaten off it's dead
for the cam. what you are really looking for is wear on the lobes.
this is what it usually looks like. It doesn't have to be that bad. if a cam starts to wear you can throw it out
compare the lobewith the pen (ground down) with the one right in front of it
to check on the lifters, they should be 100% flat at the bottom (the part that sits on the cam). If there are deep marks in eat or parts eaten off it's dead
for the cam. what you are really looking for is wear on the lobes.
this is what it usually looks like. It doesn't have to be that bad. if a cam starts to wear you can throw it out
compare the lobewith the pen (ground down) with the one right in front of it
No surprise as the seller stated there was 300 miles on the new engine.
Thanks again for the advice, I'll letcha know how it goes!
6th Gear Member
Joined: Oct 2006
Posts: 6,417
From: Cork, Ireland
well that's good news. but don't let you fool the 300miles. you've seen what 300 miles can do to pushrods :-) I've seen a cam fail already during/straight after break in (wrong procedure, high ramp rates is not a good combination).
So what's your plan?
change studs, rockers and put measured to size hardened pushrods in there?
maybe not as bad as it seems
So what's your plan?
change studs, rockers and put measured to size hardened pushrods in there?
maybe not as bad as it seems
4th Gear Member
Joined: Apr 2010
Posts: 1,027
From: NJ
If your oil of choice is API certified then it has very low levels of zddp (under 1000 ppm I believe).
Probably more than what you want to know about oil can be found in this article. Interesting read. http://www.corvetteactioncenter.com/tech/oil/index.html
Last edited by mr_velocity; Nov 18, 2010 at 02:18 PM.
Thread Starter
Joined: Nov 2010
Posts: 12
From: AR/CO
well that's good news. but don't let you fool the 300miles. you've seen what 300 miles can do to pushrods :-) I've seen a cam fail already during/straight after break in (wrong procedure, high ramp rates is not a good combination).
So what's your plan?
change studs, rockers and put measured to size hardened pushrods in there?
maybe not as bad as it seems
So what's your plan?
change studs, rockers and put measured to size hardened pushrods in there?
maybe not as bad as it seems
Will get proper pushrod length using the check I have once my pushrods are in. Additionally, I've upgraded studs to 7/16 (rockers are 7/16 as well) and guide plates for the 7/16ths. It looks like there's good room to accomodate this in the pushrod holes, so why not go even stronger!
The reduction of zddp is having a major impact on flat tappet cams. Before switching everything, right down to the lawn mower, to RedLine i was using a ZDDP additive from Valvoline (I think). I may still have a bottle in the garage, I'll have to take a look tonight.
If your oil of choice is API certified then it has very low levels of zddp (under 1000 ppm I believe).
Probably more than what you want to know about oil can be found in this article. Interesting read. http://www.corvetteactioncenter.com/tech/oil/index.html
If your oil of choice is API certified then it has very low levels of zddp (under 1000 ppm I believe).
Probably more than what you want to know about oil can be found in this article. Interesting read. http://www.corvetteactioncenter.com/tech/oil/index.html
Thread Starter
Joined: Nov 2010
Posts: 12
From: AR/CO
When I said "when the pushrods are in" I meant roller rockers, in case you're like whaaaa? lol
Will be using the CORRECT EOIC method this time once I have everything setup. BTW: Summit racing has some great deals right now. Check them out.
Will be using the CORRECT EOIC method this time once I have everything setup. BTW: Summit racing has some great deals right now. Check them out.
