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Discussion Starter #1
Installed the 1.6 Crane long slot stamped steel rockers. Seems like everything works good except I can "hear" the valve train now unlike before with the 1.5's.(and that's over the flowmasters :) ) Not one particular spot, just the whole thing.

Clearances checked out fine (very mild cam) except it was hard to measure rocker to valve stem contact with the stamped rockers to determine if I need different length pushrods.

Has anybody done this swap and is more valvetrain noise normal or would you buy one roller rocker and try and check pushrod length?

Thanks for listening to my rambling. :)
 

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Did you readjust the valves properly? Did you double check? Triple check? The majority of valve train noise that I've experienced has been from poorly adjusted lifters. I pull up and down on the pushrod until all of the play has been removed, then I go a little past half a turn for lifter preload. Seems to be just about perfect.

Kev
 

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Discussion Starter #3 (Edited)
novaboy009 said:
Did you readjust the valves properly? Did you double check? Triple check? The majority of valve train noise that I've experienced has been from poorly adjusted lifters. I pull up and down on the pushrod until all of the play has been removed, then I go a little past half a turn for lifter preload. Seems to be just about perfect.

Kev
I double checked them before firing it up, I'm gonna triple check them after they sit for a while. Just thought I'd see if anyone else had done this swap while I'm waiting. :)

I always set at 1/4 turn preload. I heard the less you can get away with the better. Maybe I'll try the 1/2 turn.
 

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stock z/28 said:
Are the push rods binding in the push rod sots?

Is that what the louis tool is for (I think that is what it is called) to lengthen the pushrod slot a bit?
 

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Discussion Starter #6
stock z/28 said:
Are the push rods binding in the push rod sots?
I'm assuming you mean the casting holes in the heads? I don't have guide plates. I was gonna check again for binding also. I didn't see any the first time around. If I still have that much noise I think I'll just swap back. For the very small gains I've heard about(if any) it's not worth the hassle.
 

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Discussion Starter #7
69NovaSS said:
Is that what the louis tool is for (I think that is what it is called) to lengthen the pushrod slot a bit?
I've heard about one of those, but know nothing about them. Wouldn't they get metal shavings in you motor? Dumb question?
 

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Repointer said:
I'm assuming you mean the casting holes in the heads? I don't have guide plates. I was gonna check again for binding also. I didn't see any the first time around. If I still have that much noise I think I'll just swap back. For the very small gains I've heard about(if any) it's not worth the hassle.
Just pull out a couple of the push rods if they are binding I would suspect it should put a mark on it somewhere. The net gain in lift is somewhere in the area of 6.7% when you switch from 1.5 to 1.6 ratio rockers.
 

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Repointer said:
I'm assuming you mean the casting holes in the heads? I don't have guide plates. I was gonna check again for binding also. I didn't see any the first time around. If I still have that much noise I think I'll just swap back. For the very small gains I've heard about(if any) it's not worth the hassle.

Not sure if that kinda thing can be done with the heads on the car but if it can I would think that getting metal in the motor might be an issue also.
 

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Discussion Starter #10 (Edited)
Sure enough, it looks like the pushrods are rubbing against the casting holes. There are no marks on them, I don't think they are binding, but very close. With the 1.5 rockers they are about perfectly centered in the holes; with the 1.6 I have less than .020". I guess that means I need shorter rods or bigger holes. :rolleyes:

Anybody want to take any educated guess on how much shorter I need to go? I would have to order them tonight if I want them here by this weekend for the drags.

I know there's probably too many variables for a guess. If I can't find an adjustable one locally for some tests, I'll just have to wait for another day. Thanks. :)
 

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Discussion Starter #12
DriveWFO said:
Ahhh, didn't I suggest to check for pushrod clearance.... :rolleyes:
Okay...Okay...you were right. ;) It least I did all the checking though. Now do ya have a guess for me? I think I'm gonna order a set along with an adjustable rod, check the length and if I'm right, I'll be good to go this weekend, if not I'll send them back unopened and get the right ones for another day. :cool:

A friend called today and we have a gang of people going out there including one guy who has a newer mustang cobra that turned a 13.3 a few weeks ago. I can't let him embarass me. :D

I think some guys from this site are heading out there too. :)
 

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Discussion Starter #13
Not to beat this to death, but it's bugging me. I assumed the push rod slots you are talking about are the holes in the head the pushrods go through? If you can see in the pic, the left is the 1.6 and right 1.5; the 1.6 rod sits very close to the bottom edge of the hole. 1) This hole is very smooth, I don't see how it could "bind" in there unless something was really bent, also I don't see how a shorter or longer pushrod would make any difference in "centering" the pushrod in the hole. 2) The only way it seems to fix it would be to enlarge the hole? Once again just trying to learn, thanks for the input.

I've been thinking about this all night. I hope this what you guys were talking about or I'm really starting to sound like an idiot. :D
 

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Yes, it appears in this case that you need to enlongate the pushrod holes in the heads. Personally, I would just run the 1.5 rockers for now and wait until you remove the heads on down the road to elongate the pushrod holes.

Also, a shorter or longer pushrod won't make any difference in "centering" the pushrod in the hole. The 1.6 rockers are shorter behind the pivot point, which changes the pushrod angle through the head and caused the interference problem.



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DriveWFO said:
Yes, it appears in this case that you need to enlongate the pushrod holes in the heads. Personally, I would just run the 1.5 rockers for now and wait until you remove the heads on down the road to elongate the pushrod holes.

Ya me too, if I had the heads off anyway it would be worth it to me to do the work involed to get the extra 6.7% increase in lift. BUT if I was not removing the heads anyway then it is a LOT of extra work for such a little increase. Just my 2 cents. :)
 

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I had the same problem several years ago and the easy solution was to run a longer pushrod. I went from stock to .100 over and the engine got considerably quieter.
 

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Discussion Starter #19 (Edited)
DriveWFO said:
Also, a shorter or longer pushrod won't make any difference in "centering" the pushrod in the hole. The 1.6 rockers are shorter behind the pivot point, which changes the pushrod angle through the head and caused the interference problem.
After thinking about it last night that's all I could come up with also. Thanks for confirming it. :)

Yea, no way am I taking the heads off for this; if they ever do come off before I swap out engines I'll just go with a new cam. Maybe use some of those secret specs. ;)

Thanks for the help guys.

Anyone use Lash Caps while were on the subject?
 

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This has been discussed before. You would have saved yourself some trouble and expense if you had
read this topic. I may merge these threads into one and put in FAQ section.
 
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