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bugguy1967 Samba Member
Joined: January 16, 2008 Posts: 4338 Location: Los Angeles, CA 90016
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Posted: Sat Dec 17, 2022 2:57 pm Post subject: Re: Home grown solid rocker shafts |
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If you have the skill, do it. The German shafts are stronger than $60 shafts anyway. I know this from machining both. Aluminum is adequate. Should 25mm O.D., I think. Use shims to align rockers. While you're machining stuff, narrow the mounts about 1mm on each side. _________________ "A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine" |
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Vanapplebomb Samba Member
Joined: November 03, 2010 Posts: 5388 Location: Holland, MI
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Sat Dec 17, 2022 6:04 pm Post subject: Re: Home grown solid rocker shafts |
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Bolt together rocker shafts are very popular, like aluminum pulleys
But they are not necessary most of the time.
I've seen the ends of the bolt together shafts fall off 3x more often than a stock clip failing.
The SPRING washers often break, but the hairpins clips are OK most of the time, at least up to 250lb open pressure.
At one time I though the rocker shafts would be "stronger" without the grooves in it, and that's true.....but rocker shafts don't break, so that KIND of strength is no issue. The sheer strength of valve train is almost never a problem because what IS important is rigidity.
If parts are rigid enough to work well then then strength takes care of itself, usually several times stronger than necessary.
The grooves for the clips or the holes in the shaft have negligible reduction in stiffness so they don't hurt anything really.
Aluminum center spacer should be fine, but also not really any better.
Several times in the past what I did was take a steel tube and weld that to the shaft for the center spacer. I cut grooves in the tube ends 180 apart and that was where the weld goes. 180 apart so you end up kinda straight, welding will warp the shaft but actually it doesn't need to be perfect. Then trimmed the ends square to the shaft in the lathe. This was easier than making a spacer at the time and also improved the stiffness of the rocker shaft.
Now I see you can buy 26mm OD by 18mm ID aluminum tube on amazon for cheap, so, that's nice.
Not sure if I have a point but I suppose in conclusion I'm not going to spend money on any rocker shaft besides stock unless it's stepped big in the middle. Just nothing to gain. In fact making the job harder |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Sat Dec 17, 2022 7:04 pm Post subject: Re: Home grown solid rocker shafts |
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Thanks Modoc! Dad and I have been into mostly stock air cooled VWs since about 1967 or so and have never seen a stock spring clip on a rocker shaft fail. I have seen some that had obvious wear on them where they contact the shims but no failures. If I were building a 200 HP 7K rpm monster then maybe yes put bolts in the ends.
As for changing up to circlips... ok... might do that... we will see. I have seen enough of those fail over the years though on other applications. Or I might safety wire the ends of the stock clips. Again I am not convinced any change is needed with stock valve springs.
As for valve train noise, I know what valve lash noise is and how it sounds. The noise I am interested in eliminating is the intermittent clatter that comes and goes especially on start up and idle. I assume this is from the rockers bouncing sideways on the shaft against the spring washers.
Interesting idea Modoc to weld the spacer in place, no set screws to come loose then. Maybe drill the spacer right through in the center and put a MIG bead in the holes on each side. Then chuck it up in the lathe and tap it straight if it needs it. Another way would be to drill both the spacer and the shaft and use a roll pin. No welding needed. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Sat Dec 17, 2022 8:03 pm Post subject: Re: Home grown solid rocker shafts |
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yeah not that hard to do.
you want quiet then get BETTER quality cam.
My engines with WEB camshafts are quieter than stock. |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Sun Dec 18, 2022 5:47 am Post subject: Re: Home grown solid rocker shafts |
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The 1641 is a stock cam but the 1911 is a Web and is the noisier one of the two. I am also going to set the valve lash closer too. Maybe try .004 instead of .006. Both are light weight Buggies so head temps are not that high. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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mikedjames Samba Member
Joined: July 02, 2012 Posts: 2714 Location: Hamble, Hampshire, UK
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Posted: Mon Dec 19, 2022 2:05 pm Post subject: Re: Home grown solid rocker shafts |
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I broke a stock rocker arm clip but then I was stupid enough to put elephants foot adjusters on the rockers. The extra side force from the elephants foot adjusters being a bit off centre on the valve stem increased the wear ..
Then what I found was that the adjuster slid down the side of the valve stem, the washer wore through, fell off in two pieces , and the clip wore through and snapped.
The exhaust valve being permanently closed caused massive backfiring that shook the flywheel off the crank, as I tried to nurse it off the motorway. It also blew out the manifold boot on the other side of the engine, so I ended up having to drive on one working cylinder and two with a massive air leak so the recovery truck could get a safe working space in front of my bus to load it up. _________________ Ancient vehicles and vessels
1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.
1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Mon Dec 19, 2022 8:31 pm Post subject: Re: Home grown solid rocker shafts |
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oprn wrote: |
The 1641 is a stock cam but the 1911 is a Web and is the noisier one of the two. I am also going to set the valve lash closer too. Maybe try .004 instead of .006. Both are light weight Buggies so head temps are not that high. |
Do that....but then re-check the lash hot after you warm it up. If you still have ~.0025"-ish and they are more quiet....good deal! Ray |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Mon Dec 19, 2022 10:07 pm Post subject: Re: Home grown solid rocker shafts |
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SURE try tighter. Maybe it's too tight. .006-.007 works good for me with aluminum pushrods and a web grind, they have about .012 of lash ramp. if I set it tighter it's louder.
But then again I did an engine where the CB cam had almost no lash ramps, maybe they were .004" tall at most, it ran quiet too, set TIGHT lash, but the whole valve train was ALL top quality stuff just near perfect.
It's not just one thing.
Pushrod cups loose it the lifter, or the rockers loose on the shaft, side play, or the pushrod ends not fitting the cups nice, valve adjusters..... that can all give you some lash VARIATION when running.
I noticed sometimes it took a while for the pushrods to wear into the rockers or lifters and get a SMOOTH fit, but if they are almost perfect fit from the start then they don't wear much.
More like.....those 'sometimes" were just not very good parts |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Tue Dec 20, 2022 6:20 am Post subject: Re: Home grown solid rocker shafts |
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Thanks! I will play with those ideas... once it warms up some. -37*C this morning so the focus will be on firewood today!
I have also wondered about setting the intakes closer than the exhausts being as the exhaust valves run hotter. Say .004 intake and .005 exhaust. Not sure if this is a valid line of thought or not. VW never did that. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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bugguy1967 Samba Member
Joined: January 16, 2008 Posts: 4338 Location: Los Angeles, CA 90016
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Posted: Fri Dec 23, 2022 2:40 pm Post subject: Re: Home grown solid rocker shafts |
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I used to make these from stock shafts for the 36ers: treated aluminum spacers, hacked the ends off and threaded them for metric hardware, made endcaps, narrowed the clamping rings, and supplied shims. _________________ "A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine" |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Fri Dec 23, 2022 3:57 pm Post subject: Re: Home grown solid rocker shafts |
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oprn wrote: |
Thanks! I will play with those ideas... once it warms up some. -37*C this morning so the focus will be on firewood today!
I have also wondered about setting the intakes closer than the exhausts being as the exhaust valves run hotter. Say .004 intake and .005 exhaust. Not sure if this is a valid line of thought or not. VW never did that. |
Yes.....that can be common. This is precisely why I set the valves to factory stock 0.006" and run it until fully warmed up and check them full hot.
You are looking to see....at the engine (and especially the heads) hottest normal running temperatures.....how far the valve lash closes up on each valve. It's not uncommon to find one valve out of 8 that has slightly different expansion. But more importantly, at least in my type 4 engine, the exhaust valves tend to close up about 0.0005"-ish more than the intake valves.
It's not uncommon to end up setting exhausts 0.001" looser than the intakes whe. You are making them tighter than the factory setting.
Pretty much on mine, I find that they never get tighter than about 0.0025" with a 0.004" setting when fully warmed up. That's just fine.
All of this depends on a stack up of variables....the quality and material of your valves, the cam, what kind of adjusters etc.
By the way, I did not start doing this type of adjusting to make my valves more quiet. I was working to get a more accurate valve lash because I run D-jet injection. It is VERY sensitive to excessive valve lash and variable valve lash.....at low speeds.
Being able to get the lash more uniform made a significant difference in tuning the lower end of the fuel mixture. It also made the valves "slightly" more quiet.....but by no .ore percentage than Porsche swivel feet and solid spacers.
Each one of these mods made the valvetrain a little more quiet....but combined....it runs and tunes a lot better with D-jet. Ray |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Fri Dec 23, 2022 5:01 pm Post subject: Re: Home grown solid rocker shafts |
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Thanks Ray! Looks like we may be getting out of the deep freeze first of next week for a few days. Then I can start the old David Brown and blow a trail out to the hay shed to move a Buggy into the garage. _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Tue Jan 10, 2023 6:10 pm Post subject: Re: Home grown solid rocker shafts |
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Here is the follow up. I got the snow out of the way, sand rail in the garage and the home grown rocker mod finished. I deviated from advice given here in a couple ways. The first being that due to a lack of either aluminum or steel in an appropriate size without robbing the drive axles out of the tractor I used bronze bushings from the local industrial parts store and machined them to suit. I did not fasten them to the shaft as I cannot see any harm coming from them rotating.
The second thing which will get a few backs up is that I reused the stock clips on the ends. There are two reasons, first is that with my limited machining experiance I did not have to deal with trying to make accurate snap ring groves in a hard surfaced shaft. The second reason is that despite what others have experiance, in 20 years of running 12 different stock air cooled VWs in our family I have yet to see a stock clip fail. Stock cams, stock valve springs. Maybe this will be the first? At any rate I will keep a close eye on them.
All set up and shimmed to zero side clearance on all rockers. Just a nice light touch to move them without any valve spring pressure. Turns out this is super easy to do. The two intake rockers just have one shim each, then I sized the brass spacers to take out all the play, with the whole thing assembled and on the head, put 4 stock shims on one end, clip on, slide the rocker shaft all the way toward the open end (yes there is enough end play due to the rocker shaft holes being larger than the studs they go on, tighten the rocker nuts to hold it all and you only have one end to shim! So - just one shim adjustment per side.
All back together with a fresh .004" valve lash adjustment and start 'er up. Pretty pleased with the results! Well worth the effort as this is beyond any doubt the quietest air cooled VW valve train in my memory!
The next victim will be the 1911 in my street Buggy! The valve train noise on it at idle is quite frankly - a bit embarrassing! _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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modok Samba Member
Joined: October 30, 2009 Posts: 26740 Location: Colorado Springs
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Posted: Tue Jan 10, 2023 8:40 pm Post subject: Re: Home grown solid rocker shafts |
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Two thumbs up. Should work great.
Middle rockers look aftermarket......cb? |
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Clatter Samba Member
Joined: September 24, 2003 Posts: 7527 Location: Santa Cruz
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Posted: Wed Jan 11, 2023 12:03 am Post subject: Re: Home grown solid rocker shafts |
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oprn wrote: |
The noise I am interested in eliminating is the intermittent clatter that comes and goes |
Nice work. _________________ Bus Motor Build
What’s That Noise?!? |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Wed Jan 11, 2023 4:39 am Post subject: Re: Home grown solid rocker shafts |
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modok wrote: |
Two thumbs up. Should work great.
Middle rockers look aftermarket......cb? |
Thanks all!
Good eye Modoc! Unfortunately they are EMPI brand 1.25 rockers. Quite soft compared to the stock rockers so I will see how they last. I am also a bit concerned that they hit more toward the top of the valve stem but when mixing 1.1 and 1.25 rockers it's a compromise? _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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madmike Samba Member
Joined: July 11, 2005 Posts: 5291 Location: Atlanta,Michigan
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Posted: Wed Jan 11, 2023 5:32 am Post subject: Re: Home grown solid rocker shafts |
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Good Job Merv, _________________ 'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Wed Jan 11, 2023 7:53 am Post subject: Re: Home grown solid rocker shafts |
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Thanks Mike, especially for your help. The shims worked out great. I ended up only using 5 of them so lots left for future engines! _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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esde Samba Member
Joined: October 20, 2007 Posts: 5927 Location: central rust belt
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Posted: Wed Jan 11, 2023 8:06 am Post subject: Re: Home grown solid rocker shafts |
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It's cheap insurance to use some safety wire to bind the ends of the spring clip together. I do this on my 36hp, with a solid spacer in the middle to eliminate the big spring. _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
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