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BB valve train set up question
#640726
03/15/10 06:42 AM
03/15/10 06:42 AM
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Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
The_Mean_Machine
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Löffingen, Germany
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I’m in the process off setting up the valve train on a 383 / 496 stroker engine with Indy 440ez heads, roller cam, Comp Cam hydr. Retrofit lifters, Hughes Aluminum Roller Rockers with hold down studs and billed hold downs. Hughes recommends to set up the valve train in a way that the push rod and the rocker adjusting screw are in one common line @ 50% of the valve lift. In order to achieve this I would need to raise the rocker shaft approx. 0,060”. This would require some special shims (common radii inside and outside, see pic:)  and are quite tricky to manufacture. The question I have: is it really necessary to go through this effort or in other words, what is the technical background making it important to have this common line? Generally I would say in a perfect world the forces on the adjusting screw are minimized and therefor wear on the valve train is minimized. But since this is more a theoretical value (50% of valve lift is passed 2 times per opening cycle) do I really gain a lot by adjusting it? Btw, the attached picture shows the angle @ 50% valve lift without any shims…  and here is the wipe pattern without shims (the inboard mark comes from fooling around with the rockers  :) 
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Re: BB valve train set up question
[Re: Mr.Yuck]
#640728
03/15/10 07:18 AM
03/15/10 07:18 AM
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Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
The_Mean_Machine
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Quote:
not sure what's up with all that math but you can shim up your shafts. I had to do it on an old 383 I had that was decked and heads were milled. Any spped shop should have the shims you need.
the shims available are just pieces of bend sheet metal with a constand material thickness. Such shims will leave a gap in the lowest point of the shaft saddle and I am afraid of loosing oil pressure were the rocker shafts are feed. Btw. Dimensions in the sketch are metric...
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Re: BB valve train set up question
[Re: The_Mean_Machine]
#640729
03/15/10 08:20 AM
03/15/10 08:20 AM
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Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Quote:
not sure what's up with all that math but you can shim up your shafts. I had to do it on an old 383 I had that was decked and heads were milled. Any spped shop should have the shims you need.
the shims available are just pieces of bend sheet metal with a constand material thickness. Such shims will leave a gap in the lowest point of the shaft saddle and I am afraid of loosing oil pressure were the rocker shafts are feed. Btw. Dimensions in the sketch are metric...
I dunno what to tell you boss. I ran them for 2 years w/o a problem. This was a 383 that I shifted at 6800 and ran the snot out of it. It had plenty of oil pressure.
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Re: BB valve train set up question
[Re: BELVEDERE67]
#640732
03/15/10 11:58 AM
03/15/10 11:58 AM
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Joined: Apr 2006
Posts: 3,675
Akron, Ohio U.S.A.
roadhazard
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Akron, Ohio U.S.A.
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Quote:
When looking at the roller travel across the valve tip, I don't really think you need it. 
 It's wiping in the middle of the valve in it's travel.
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Re: BB valve train set up question
[Re: roadhazard]
#640733
03/15/10 02:44 PM
03/15/10 02:44 PM
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Joined: Nov 2004
Posts: 2,825
Sk. Canada
RemCharger
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Sk. Canada
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Quote:
Quote:
When looking at the roller travel across the valve tip, I don't really think you need it.
It's wiping in the middle of the valve in it's travel.
That and the shims are NOT a complicated deal. Ten, one inch sqare pieces of aluminum with a hole in the middle. 
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Re: BB valve train set up question
[Re: RemCharger]
#640734
03/15/10 02:48 PM
03/15/10 02:48 PM
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Joined: Jan 2004
Posts: 27,347
Today? Who Knows?
1_WILD_RT
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Today? Who Knows?
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Quote:
Quote:
Quote:
When looking at the roller travel across the valve tip, I don't really think you need it.
It's wiping in the middle of the valve in it's travel.
That and the shims are NOT a complicated deal. Ten, one inch sqare pieces of aluminum with a hole in the middle.
While I agree the pattern looks good & I would run it as it is the issue with rocker shims that most seem to not think is any big deal can be.. I've seen enough rocker pads split from using flat shims to say you should use conoured shims..
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Re: BB valve train set up question
[Re: 1_WILD_RT]
#640735
03/15/10 03:34 PM
03/15/10 03:34 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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You are overthinking it. Just get some soft copper flat washers of the right thickness with the bolt hole dia correct (larger dia for the pedestal that feeds the shaft) that will easily conform to the saddles, mock them up & get the straight line @50% then check the wipe pattern. The wipe pattern is more important than the straight line but get the straight line 1st and If you are feeding the shafts up from the cam I would consider oiling in horizontally from the back of the heads then angling up to the rear pedestal and restricting the crank to cam feed passages w setscrews w a 1/16" hole drilled in each one which is plenty of lube for the cam bearings/journals but one problem at a time.
live every 24 hour block of time like it's your last day on earth
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Re: BB valve train set up question
[Re: RapidRobert]
#640736
03/15/10 05:14 PM
03/15/10 05:14 PM
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Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
The_Mean_Machine
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Thanks for the feedback so far. So the wipe pattern is more important than the straight line between PR and Rocker Adjusting Screw? Can someone adjucate me why? And honestly, I do not believe the 'whatever soft material the of the shelf shims are made of' can be compressed this much to really gap 0,016" at the bottom of the rocker saddle and provide sufficend distributed clamping force... But maybe I am realy pushing it too far  Thanks Frank
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Re: BB valve train set up question
[Re: The_Mean_Machine]
#640737
03/15/10 05:21 PM
03/15/10 05:21 PM
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Joined: Nov 2004
Posts: 2,825
Sk. Canada
RemCharger
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Sk. Canada
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Quote:
Thanks for the feedback so far.
So the wipe pattern is more important than the straight line between PR and Rocker Adjusting Screw?
Can someone adjucate me why?
And honestly, I do not believe the 'whatever soft material the of the shelf shims are made of' can be compressed this much to really gap 0,016" at the bottom of the rocker saddle and provide sufficend distributed clamping force...
But maybe I am realy pushing it too far
Thanks
Frank
Its just an old plymouth.
You will be fine without doing anything, just put it together.
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Re: BB valve train set up question
[Re: RemCharger]
#640740
03/15/10 05:45 PM
03/15/10 05:45 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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I'm curious why Hughes would borther with that... You can't adjust either location (lifter or rocker screw placement). You can minimize the sideways push on the screw by having minimum threads exposed (the longest pushrod you can for your assembly...) but that's it. What I learned is you want the roller on the exhaust flange side of the valve tip at exactly 1/2 lift. The arc the roller traces places it furthest from the shaft centerline at mid lift if the geometry is correct. The sweep looks a little narrow to me but if the cam's moderate that would be why. It placed well, providing the tip starts on the inboard side on the base circle, then moves accross the tip to the exhaust flange side at mid lift, then back to the inboard side at max lift. Needing correction is the result of the valve job being off. I'm hoping the heads were fixed rather than out of the box. I would not run shims if this needs to go higher in the rpm range (above6500) on a regular basis. Shims do not allow for the best support of the shaft.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: BB valve train set up question
[Re: The_Mean_Machine]
#640742
03/15/10 06:57 PM
03/15/10 06:57 PM
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Joined: Feb 2005
Posts: 4,310
Prospect, PA
BSB67
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Prospect, PA
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My opinion is you are okay with what you have. How and where did you measure your 50% lift?
Mancini use to have tapered shims and you might check with RAS.
Last edited by BSB67; 03/15/10 07:47 PM.
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Re: BB valve train set up question
[Re: RemCharger]
#640743
03/17/10 07:57 AM
03/17/10 07:57 AM
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Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
The_Mean_Machine
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Quote:
Actually looking back at your pictures,,, do you have enough rocker to retainer clearance? 
What kind of rockers are they and whats the cam specs?..... 
this is the cam, installed @104°
Rocker to retainer clearance is fine...
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Re: BB valve train set up question
[Re: roadhazard]
#640744
03/17/10 07:59 AM
03/17/10 07:59 AM
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Joined: Jan 2003
Posts: 2,325
Löffingen, Germany
The_Mean_Machine
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Quote:
Actually I might be more concerned with the valve locks
Are those stamped locks or machined? If they are not machined I'd toss them
Also I would machine and put rockershaft stands on there before I'd use a shim. another
The locks are the ones supplied with the heads from Indy. I would say they are stamped, but I am not 100% positive.
Whats the failure mode with stamped locks?
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.(keeps you in the mindset of seeking perfection in every subsystem and it all adds up in the end.)
