Alright, here's my deal

ZZ4 shortblock, bought ARR190's and had them milled 30K and it was measured at 65cc The heads were rebuilt with all new parts but still has 2.02/1.6 valves(Manley Race Flo)

I have also put in a CC 276HR-14 cam with 1.6 roller tip rockers so that gives me a 220/229 dur @50 and .544/.544 lift

I haven't had many miles on the build and it's broke already. I never really had it tuned right and had it dynoed and after the dyno is when I noticed the problems. The car would shake bad at idle and the vacume gauge was bouncing from 11-15. The car also had trouble accelerating.

I have since found that my #6 intake pushrod was bent and the lifter was all apart(clip broke)

My question is can the lifters that came in the ZZ4 handle a .544 lift? Also, do you think I have enough valve/piston clearance? what would cause the vacume gauge to bounce liek that? there were no vacume leaks.

 

you may be having a problem with pushrod legnth after changing rockers and milling the heads. i'd start there. the lifters should be fine.

 

The lifters don't care about the lift.

The reason the lifter came apart was becasue the push rod broke. There was nothing wrong with the lifter until that happened.

Your problem is probably the valve springs, or the rockers you used.

 

well, just wondering if I did get the right pushrods

CC780816 is what I have on here, the pushrod is chewed up pretty good in the area where the guidplate was.

I told Comp Cams what I had and that was the number they gave me as well as the springs

 

The push rod is not the cause of the failure, it is merely another victim of something else.

What springs do you have?

Do you have self-aligning rockers?

 

the vacuum guage problem is from the bent pushrod. i've ran into this problem a couple times with the pushrod being too long, but also have had a problem with the pushrod hitting the head on certain applications. milling the heads changes the angle of the pushrod slightly and also brings the pushrod closer to the lifter. i'd contact comp cams or afr and tell them also to see what they say or just check clearances.

 

I have cc98716 springs and don't have self aligning rockers because I have guideplates. here's a pic of the pushrod

I will call CC and see what they think. it almost looks liek the pushrod rubbed on the guidlplate by the looks of it.

 

Looks like the push rod rubbed on the inside of the slot in the guide plate and was pushed up out of its seat in the rocker. Pretty definitely was forced to bind on the guide plate somehow. Sometimes this happens from contacting the hole in the head below the guide plate, but I don't see a wear mark where that would leave one.

Grind or file the slots in the guide plates deeper, but be careful not to widen them. Since those are evidently the flat guide plates you should be able to lengthen the slots quite a bit.

Next time, you also might want to use the 7400 series push rods, they are a much better piece.

 

have a part number? I don't see 7400

it's a lot more money but I think the 249-7372-16 would work

one piece 1010 chromoly with a .080 wall thickness and heat treated for use with guideplates