Bob Hoover HVX mods on wbx?

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Dan Dryden
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Bob Hoover HVX mods on wbx?

Post by Dan Dryden » Sat Mar 26, 2016 4:13 pm

Has anyone done these mods on their wbx?
I imagine they are more useful to anyone who's done a type 1 lifter conversion.

Also, does anyone have better copies of the diagrams in Bob's blog? I'm struggling to see how he has done the oiling mod at the no3 cam bearing...

http://bobhooversblog.blogspot.co.uk/20 ... -mods.html

AMBROSIA
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Re: Bob Hoover HVX mods on wbx?

Post by AMBROSIA » Tue Mar 29, 2016 4:19 am

Now that i'm going solid lifters i'm also considering doing these mods.
Interesting that VW went back to T1 style from T4 for the WBX in several areas.
The lifters I have (Thorsten) already have a wide oiling groove much like the standard hydro units.
Next time I speak to my machinist I will see what his thoughts are.

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Dan Dryden
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Re: Bob Hoover HVX mods on wbx?

Post by Dan Dryden » Tue Mar 29, 2016 6:26 am

I wonder if VW went back to the type 1 system on the wbx because it was less reliant on oil to cool the heads...?
I imagine they did these mods to the typeIV to enable superior head cooling, especially when carrying the weight of those heavy vans around!
Extra oiling to the rockers was perhaps seen as a positive by-product...

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Piledriver
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Re: Bob Hoover HVX mods on wbx?

Post by Piledriver » Tue Mar 29, 2016 2:07 pm

It needs ~all the same mods.
The biggest step back was the "through-lifter-bore" oiling of most lifters.
The T4s lifter oil feed runs across the top of all bores, only ~1/2 blocked by a lifter so all lifers get oil all the time.

The bigger cutouts on the hydros make up for this, IMHO any mechanical lifters used should be ground top about the same profile if the thickness of the lifter bodies allow.

You can also use a dremel and a ball mill to make a shallow radial passage around the lifter bores connecting all bores.
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AMBROSIA
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Re: Bob Hoover HVX mods on wbx?

Post by AMBROSIA » Wed Mar 30, 2016 7:11 am

The lifters I will be using.

Image

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Dan Dryden
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Re: Bob Hoover HVX mods on wbx?

Post by Dan Dryden » Thu Mar 31, 2016 3:48 am

Why only one oiling groove?
Will this not restrict the flow similarly to a non modified type 1 lifter?

buildabiggerboxer
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Re: Bob Hoover HVX mods on wbx?

Post by buildabiggerboxer » Fri Apr 01, 2016 12:15 pm

Like all today's mods I carry out, Are they REALY neccasary, my motors were quick enough in the biggining of time when I knew naff all, touching on the topic of HVMX, well I never had oil problems , in fact, some of the 'mistakes' I made back then, turned out to be good colestral, I could get no data sheets from VW when the Wasser 2.1s first cam out, I was on my own, so I had to use what knowledge I already had, that's how I found 32lb/ft works well on Conroe eye bolts, if I'd extra twisted them like the factory, id've been in deep ****
That's also how I found out German intake guides come lose in racing and grenade the motor if it happens at 7200 rpm, and yes, the stock springs will pull that rev ceiling if the valve train is super light, beware German retainers for high revs, I find they wear in the taper, AMC ones are superb but heavy, machine and lighten to make a quality lifter, hard? They are that!
Today, my Wassers DO get HVMX, but they are race motors on right hand circuits, so to help with less oil slosh to the right, the right head gets extra forced oil, I also run valve Spring cooling off the rockers and inlet valve sticking is a problem on race motors, it was obvious to Cary out the mod as I fit case plugs and plenty other machining is done on the case anyway. In short, to answer the question, No, it's not NECCASARY, Bob Hoover saw short comings because he needed an aero spec oil system were he saw g I would emagine, same as I do on circuits.
But Wasser size oil grooves in the lifters are a good move in any performance motor, my T1 style lifters are all machined thus in any engine, air cooled included, T1 crank cases vary hugely in detail design, the HVMX drilling often breaks through the case at the Depression in the right half, not had a Wasser case do it yet.
As to oil pickup pipe mods, a wet sump race motor seeing any g will need a shorter pickup tube as the oil pool is biased to the rear of the sump, it's very tapered, a good alternative is to run more oil, a better alternative is to go dry sump, the Wasser lends itself perfectly to Beetle installs with an engine raise by inclining the engine and trans assembly, a must for track work. Redirecting the spill oil can be done as ten cent does on his builds, but again, my turbo has stock pick up and has no oiling problems, my OKRASA has a modified spill oil circuit like T1 cases, but I left the tube alone and blocked of the case transfer port to redirect the oil to the sump via a new port drilling in the case, again, I see no difference in oil performance between the motors, the turbo runs hotter as it should, but not to the danger point. The KISS rule is still to be respected, I'm not gonna try to make my beetle, or bus come to that, a Porsche or a Subaru, where's the fun in that..

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Piledriver
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Re: Bob Hoover HVX mods on wbx?

Post by Piledriver » Fri Apr 01, 2016 6:41 pm

The shorter pickup tube may work better due to other reasons...

I read an interesting article on high RPM v8s recently that is making me reconsider the oil back to sump vs. short oil back to pump loop.

I'll try to find the article, has been awhile...

To make a long story short, they ran some calculations, did some testing, and at high RPM, the pump would usually cavitate if it had to suck all the way back to the pickup, the short bypass loop flow (which is really most of the oil at high RPM) prevented that from occurring.
(In the SBC pumps the bypass oil never leaves the pump)

The pump in question was IIRC a std hipo SBC oil pump, gears are same dia but shorter than a stock T1 VW pump. (.750"/~19mm, OD T1 is 21mm, T4 is 26mm from factory)

Of course Bob Hoover always said that his calcs showed the stock T1 oil pump was 7X oversize to begin with, allowing for stock clearances...

In a somewhat related note, i'm trying to figure out it it would be practical to repurpose/modify something like a GM emission AIR pump as a centrifugal air/oil separator, like Daily Engineering is working on.
They make an apparently effective unit as an option on their dry sump pump stacks.

It's basically a (internally) very leaky centrifugal pump, and the lighter foam and air "float" to the center of the hollow impeller and out to the top of the oil tank, while de-aerated oil is sent to the bottom of the DS tank via another hose.

BBC@10K RPM dyno pull, clear DS tank with/without their DS pump and air/oil separator unit
https://www.youtube.com/watch?v=noO16P5vSwQ
They were kind enough to briefly show off their design in the cutaway in this vid:
https://www.youtube.com/watch?v=qJxMNcHRvpU
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

AMBROSIA
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Re: Bob Hoover HVX mods on wbx?

Post by AMBROSIA » Mon Apr 04, 2016 5:12 am

Why only one oiling groove?
Will this not restrict the flow similarly to a non modified type 1 lifter?
All the tool steel light weight lifters I have seen are the same design.
The groove is larger than one of the single stock ones but certainly much smaller than a hydro lifter.
I'm thinking it would be easier to modify the bushes by perhaps adding a chamfer to the oiling holes?
Image

I'm still unable to move forward as the lifter/bush combinations I tried so far are all out of spec.
One view is that there is insufficient 'crush' from the existing bores due to wear.

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Dan Dryden
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Re: Bob Hoover HVX mods on wbx?

Post by Dan Dryden » Mon Apr 04, 2016 6:10 am

I guess the answer to your problem, Ambrosia, is to get the bores drilled out and find someone willing to make over sized bushes..... Sounds easy when you say it!

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Dan Dryden
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Re: Bob Hoover HVX mods on wbx?

Post by Dan Dryden » Mon Apr 04, 2016 6:14 am

Piledriver, those air/oil separators look very effective! How would you incorporateo one into a VW pump? Surely it would make it protrude so far out you would be very restricted on exhaust header options?...

AMBROSIA
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Re: Bob Hoover HVX mods on wbx?

Post by AMBROSIA » Mon Apr 04, 2016 9:43 am

I guess the answer to your problem, Ambrosia, is to get the bores drilled out and find someone willing to make over sized bushes..... Sounds easy when you say it!
I'm exploring options with JC at stateside.
TBH we are only talking 0.03mm out of spec and that's within the spec range of the lifters.
I did briefly speak to the guy working on my engine case regarding the oil mods.
He has performed oil gallery widening on race motors but for different reasons.
Loss of oil pressure on the center crank bearing feed and the conrods leave the case.

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Re: Bob Hoover HVX mods on wbx?

Post by Piledriver » Mon Apr 04, 2016 11:41 am

Dan Dryden wrote:Piledriver, those air/oil separators look very effective! How would you incorporateo one into a VW pump? Surely it would make it protrude so far out you would be very restricted on exhaust header options?...
That's why I want an electric one, it could go almost anywhere.
Daily Engineering is working on an electric version...
It doesn't make ~any pressure, and has loose tolerances by design, so should be reliable, and not require a huge electric motor, it just has to fling oil, inertia and the fact that oil is heavier than air does the trick.

On a T4 its a bit easier to package things for belt drive, as the exhaust goes down... and can even go forwards.
I actually have a spot under my AC compressor where a DS pump and//or vacuum pump could live. Made it with a serp belt for a reason.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

buildabiggerboxer
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Re: Bob Hoover HVX mods on wbx?

Post by buildabiggerboxer » Sat Apr 09, 2016 12:17 pm

Dan Dryden wrote:Has anyone done these mods on their wbx?
I imagine they are more useful to anyone who's done a type 1 lifter conversion.

Also, does anyone have better copies of the diagrams in Bob's blog? I'm struggling to see how he has done the oiling mod at the no3 cam bearing...

http://bobhooversblog.blogspot.co.uk/20 ... -mods.html
Image

Dan, here you can see the new drillings to connect up the oil feed to the normaly blind #3 cam bearing, this one broke out and required welding. Best, Johnny.

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Re: Bob Hoover HVX mods on wbx?

Post by Piledriver » Sat Apr 09, 2016 12:38 pm

I have done it on 3 cases with no breakout...
If it gets out or not is simply down to case manufacturing variations.

You do want to use as large a drill as fits, too small a bit may wander.

Its just as vital if you build a motor using t4 solid lifters, as they don't have much for oiling grooves like the hydros, and the bodies of the lighter ones you want are too thin to machine the same as the hydros.

OTOH you could fairly easily "shim up" a set of hydros so they were solids.
That would make for a reasonably light lifter, as they are hollow, and oil is much lighter than iron.

I'd have them reground to the proper radius and Parkerized, there's at least one fellow here in the states that does it.
The last 2 sets of normal out of the box lifters I looked at had no detectable face radii, dead flat. That's wrong.
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