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  #16 (permalink)  
Old 07-05-2009, 03:30 PM
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Yea according to your part # he sold you the right rockers 1.6 for 3/8 stud. In most cases you can go .100" over on the pushrod and be ok. JMO Cole

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  #17 (permalink)  
Old 07-05-2009, 03:38 PM
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Quote:
Originally Posted by eloc431962
Yea according to your part # he sold you the right rockers 1.6 for 3/8 stud. In most cases you can go .100" over on the pushrod and be ok. JMO Cole
What about the p-rod hole in the head. With 1.6 ratio rockers, the hole should at least be checked and be opened up if using a cam like the Comp 268XE.

The lifters (if they're for a SBC) should be the same length as what came out of it. Is the cam a reduced base circle cam by some chance?
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  #18 (permalink)  
Old 07-05-2009, 03:55 PM
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I totaly agree cobalt they should at least be checked and opened up if needed. Cole
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Old 07-05-2009, 04:14 PM
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There is about a 90% chance that 1.6 ratio rockers will cause the pushrod slot to interfere with the pushrod at the stud end of the pushrod slot. To make a 1.6 rocker, they just move the pushrod cup towards the stud on the rocker body.

You can't just slap a 1.6 rocker on and go.
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Old 07-05-2009, 04:21 PM
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I agree with tech i. You are going way too far. Intake closes, set the exhaust.
Exhaust opens, set the intake. Move pushrod up and down while adjusting.

with 416 heads + 1.6 rockers the slot in the head need to be lengthened towards the rocker stud. (5/16" rat tail file in a drill.) longer slot , not wider.

If the new valve job seat depth location in the head results in the valve seat location not being as deep in the head as stock, then the geometry will be off.
Possible valve seat machining error if larger diameter valves were installed.

Possible ford rockers. Non chev rocker pushrod seat, rocker tip geometry.
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Old 07-05-2009, 04:33 PM
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Trust me on this one, my valve adjustment is correct, this has been verified by a person who knows for sure how to do it, im just having a hard time explaining how i adjust them, this is not my native language you know

Rockers are chevy rockers, lifters are stock height, i measured my pushrods, they are stock (compared to another stock sbc pushrod). Cam could be smaller base circle.. thats the only place that could be "shorter" than stock.

I cant locate the thread now but i read about this same problem here couple of days ago, cant remember what was the reason why it happened on that case..
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  #22 (permalink)  
Old 07-05-2009, 04:52 PM
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Quote:
Originally Posted by maliboo
Cam could be smaller base circle.. thats the only place that could be "shorter" than stock.
I don't recall the other thread just now.

There are different length valves, if they were changed during the head work that was done, they might account for it.

It's just that thousands of those rockers have been installed on heads like yours- w/o drama. So if there's nothing wrong w/how they're adjusted, it's something in the parts themselves.

I would start measuring things, as compared to known "correct" or OEM parts. Something is short, and not just a little bit, to cause this to happen, IMO.

How much thread is showing above the adjuster nut? Or are you using P-locks? If poly locks, is there plenty of engagement for the locking allen head?

Is the same thing happening on both the intake and exhaust valves? ALL the valves, or just some of them?

EDIT- If you think it'll help, I can walk out to the shop and measure the amount of valve stem that extends up past the valve guide boss on the valve cover side of the head (stock head and valves)- for a comparison to what yours measures.
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  #23 (permalink)  
Old 07-05-2009, 05:52 PM
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Quote:
Originally Posted by techinspector1
Using the twist method, I'd say that you definitely do not know how to adjust valves
Comments like this make me laugh. I use this method all the time and I definitely know how to adjust valves.
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  #24 (permalink)  
Old 07-05-2009, 08:04 PM
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Quote:
Originally Posted by engineczar
Comments like this make me laugh. I use this method all the time and I definitely know how to adjust valves.
Yeah, well maybe that was too sweeping as a general statement, but you've probably done this thousands of times and have a feel for it, whereas the OP hasn't your experience.
Cut this old man some slack, dude.
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Old 07-05-2009, 08:10 PM
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Quote:
Originally Posted by engineczar
Comments like this make me laugh. I use this method all the time and I definitely know how to adjust valves.
I was going to say what the Inspector did too. The "spin" method gets more amateur's in trouble and I don't like it either, especially with hydro lifters. I know how to use this method too, but it shouldn't be a recommended method.
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  #26 (permalink)  
Old 07-05-2009, 09:35 PM
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I really don't want to turn this into a thread about how to adjust valves. The process of setting the valves is inherently a precise procedure no matter how you do it and does require a pretty good sense of feel to get it right no matter which procedure one chooses to use. However just because someone poses a question doesn't automatically make a person an amateur and I think it does a tremendous disservice to the original poster to imply that he doesn't have the skill to adjust the valves a certain way. I don't think the problem he's having is related to how he's adjusting his valves but has more to do with the combination of parts he's working with.

Like what has already been posted I would check the clearance of the pushrod slot due to his using 1.6 rockers. I would also check with the machinist as to whether or not the valves are stock length or +.100, other things to consider are the combination of deck height/head gasket thickness/head deck thickness combining to necessitate a longer pushrod or just a plain old out of whack head casting that has left the rocker stud bosses too high. While nice pieces the Scorpion rocker arms do tend to be a pretty bulky design.
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  #27 (permalink)  
Old 07-05-2009, 10:16 PM
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Quote:
Originally Posted by engineczar
However just because someone poses a question doesn't automatically make a person an amateur and I think it does a tremendous disservice to the original poster to imply that he doesn't have the skill to adjust the valves a certain way.
But assuming an OP (not this thread's OP) has mad skilz is the one thing that most often gets me burned when giving advice! lol

It seems if I give credit for knowing the basics, sure as heck, the next post will be that all the "carb problems" were really a burned plug wire that the lawn service guy found while he was there cutting the grass! And then if I were to go into some long, drawn out description of how to tune the idle circuit of his carb, he'll come back and say, "Oh, BTW, I'm the head technician at XYZ Carb Co.".

Quote:
I don't think the problem he's having is related to how he's adjusting his valves but has more to do with the combination of parts he's working with.
That's what it's sounding like, as long as the OP has a grip on the valve adjustment thing. Which brings us back full circle!
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Old 07-05-2009, 11:04 PM
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I cannot see how valve adjustment could even solve this. If i cannot even apply preload, on some valves i cant even get all the lash away before rocker gets jammed, it cannot be the reason why it does this. Good to check of course, but in this case it isnt the case. As for if i know how to do it or not, why does my engine work with stock rockers perfectly, and has done so after many times ive been adjusting them....?

Nuts are polylocks, and the allen nut is about at the same height than the hex nut, so it really does not come out too much.

I have to speak with the machinist who did my valve job. Maybe he used long-tip valves. The locking groove, however, is at correct height, i know this because i measured valve spring heights and they were same as stock..
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  #29 (permalink)  
Old 07-05-2009, 11:07 PM
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When the valve lifter is all the way down in the lifter bore and on the cam base circle, does it sit below the edge of the lifter bore? (Lower than with a stock GM cam) What cam is in the motor?
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  #30 (permalink)  
Old 07-08-2009, 03:44 PM
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Quote:
Originally Posted by F-BIRD'88
When the valve lifter is all the way down in the lifter bore and on the cam base circle, does it sit below the edge of the lifter bore? (Lower than with a stock GM cam) What cam is in the motor?

Lifter sits right at the edge of its bore when its on the base circle. Camshaft is Comp Cams xtreme energy with 268 / 280 adv. duration.

I talked with the machine shop dude. Valves are stock length.

Maybe my heads just are more bulky than normally, for some odd reason? Anyway, in this case these rockers wont fit without removing heads, so I'll just have them converted to threaded studs and machine stud bosses down. Then check for pushrod length and buy new pushrods if necessary.
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