Bob Hoover's HVX VW Engine Mods.

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Pops

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(New guy here, trying to sort out the gems from the dross.) How closely does your shop balance the rods? IIRC, Bob Hoover was pretty insistent on that as well.

Alan
Says in my post to within one gram. In doing the MOH on my C-85-12F, the book says rods within 10 grams, I went to 1 gram. The 1835 VW engine in my SSSC has the rods within one gram and the CR on each cylinder at 7.55- 1 and the engine is very, very smooth and powerful.
 

ArcticDave

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Dan, I have a question if I may?
I did all of the Hoover mods to the engine I'm building now, but I did not groove the rocker bushings. I grooved the shafts and nearly gave myself a fit trying to figure out how to do the rockers. How did you do it?

Also,on the last page you were discussing power generation. Have you considered adding a solar panel to support that flywheel drive engine? I have a flexible panel that fits the section over the cabin, that outputs enough amps to run the ignition and charge the battery. Just something to chew on...
 

Pops

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I buy the thin 3" or4" dia, ( 1/32" thick) cutoff wheels at the local hardware store. Drill a 1/16 hole and cut out a very small disk with aviation snips. I use it in a dremel tool with a flex shaft that has a very small chuck to get inside of the rocker arm I.D. Hardest job of the mod.

With the additional oil flow you will lose some oil pressure. I lost about 8-10 pounds when hot. To gain the pressure back I removed the oil pump cover and took out the .004 stock paper gasket and make a gasket for .0025 gasket material from NAPA. That is reducing the cover clearance for the face of the oil pump gears from .0045 to .003" and gave me the oil pressure that I lost with the mods.
When everything done I had 42 lbs hot at cruise rpm and hot idle at 950 rpm at 20 psi.

Plan on using a solar panel on the top of the instrument panel below the big flat windshield to charge the 12 battery that runs the handheld radio and the electric elevator trim and the oil temp gauge on the JMR.
 

J.L. Frusha

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I had this engine case checked out by the local VW engine only machine shop that I have been using since 1970. Yesterday I saw something that didn't look right. At the top of the bore in the case where the lifter for the intake valve for #1 there was a very, very small line that looked out of place. With a strong light and a magnifying glass, there was a small crack starting at the top and starting to go down in the bore. The shop must of missed it, I can see why. Not going to use the case. It would be OK for a 1/2 VW if someone wanted to build one. Bored for 92 pistons and cylinders, and cleared for a stroker crank. So, I dug out another case that I have that is good and did all the drilling and thread tapping and enlarging the oil passages on it the rest of the day.
Next thing on the HVX mods will be the rocker arms and the rocker arm shafts. Making the grove inside the rocker arm bushing is the hardest part of doing the Mods. Also when doing the mods to the shafts, it makes the shaft end locked to a certain end of the heads.
I'd be interested in a 1/2 VW version with these mods. Not real soon... No money, no funny, but... Seriouly looking at a 1-off attemt at an ultralight based off the P-51 cartoon-scale trype profile mods I've don in MS Paint. Basically start at 50% scale, shorten the fuselage for and aft of the cabin, stretch to chord a tad, keep the 50% scale cabin and tail-feathers and maybe reduce the wingspan a smidgeon, with a Malcolm Hood style canopy. Dunno if it can be done, but it can't if I don't try, at any rate.

Any idea what a 1/2 VW with these mods would cost? I've got a couple of projects in the works that may end up as money-makers.

What magneto is there?

Anyone know of a recoil start conversion, like some of the old lawnmowers, spin a crank to wind a coil spring, hit a mechanical release to turn the engine over...?
 

Vigilant1

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I buy the thin 3" or4" dia, ( 1/32" thick) cutoff wheels at the local hardware store. Drill a 1/16 hole and cut out a very small disk with aviation snips. I use it in a dremel tool with a flex shaft that has a very small chuck to get inside of the rocker arm I.D. Hardest job of the mod.

With the additional oil flow you will lose some oil pressure. I lost about 8-10 pounds when hot. To gain the pressure back I removed the oil pump cover and took out the .004 stock paper gasket and make a gasket for .0025 gasket material from NAPA. That is reducing the cover clearance for the face of the oil pump gears from .0045 to .003" and gave me the oil pressure that I lost with the mods.
When everything done I had 42 lbs hot at cruise rpm and hot idle at 950 rpm at 20 psi.
Pops, you should write a book on aero VWs. HVX mods (details on how to do them), your carb heat oil box, which sealants/lubricants work for what, all the tricks to doing a proper rebuild and for regular maintenance. You would not need to start from scratch: Maybe take the Great Plains Engine Assembly Manual as the foundation/memory jogger and write your tips as additions/comments/footnotes to that. You've already got a lot of the text and some photos finished--as posts you've written here.
There, just what you need--another project!
 

Pops

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Pops, you should write a book on aero VWs. HVX mods (details on how to do them), your carb heat oil box, which sealants/lubricants work for what, all the tricks to doing a proper rebuild and for regular maintenance. You would not need to start from scratch: Maybe take the Great Plains Engine Assembly Manual as the foundation/memory jogger and write your tips as additions/comments/footnotes to that. You've already got a lot of the text and some photos finished--as posts you've written here.
There, just what you need--another project!
LOL , Yes , just what I need is another project. JMR is not flying yet, I stated a VW pipe buggie that is ready to paint. Need to finish the 1835 cc engine for the buggie. Need to finish the flywheel drive 1835 VW engine that I started. What is it going on? Don't know maybe another SSSC. Just need to finish what I have started.
Its a sickness I tell you, its a sickness.

I do have about 15 chapters written of a book for the grand and great grand children of the family history from 1754 up to including me and my children. I have lots of records on the subject, other books written about my ancestors, court records, Civil war capture and POW papers, etc. Also the highs and lows of the family in all of those years. From wealthy to poor, etc.
Have had a family member in every war of this country up to my oldest son. I have a grandson named after a Minute Man and Indian Scout for George Washington and George Rogers Clark . So much information its hard to condense it down so its not so long. Need to get help from my English Major grand daughter.
 

ArcticDave

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I buy the thin 3" or4" dia, ( 1/32" thick) cutoff wheels at the local hardware store. Drill a 1/16 hole and cut out a very small disk with aviation snips. I use it in a dremel tool with a flex shaft that has a very small chuck to get inside of the rocker arm I.D. Hardest job of the mod.

With the additional oil flow you will lose some oil pressure. I lost about 8-10 pounds when hot. To gain the pressure back I removed the oil pump cover and took out the .004 stock paper gasket and make a gasket for .0025 gasket material from NAPA. That is reducing the cover clearance for the face of the oil pump gears from .0045 to .003" and gave me the oil pressure that I lost with the mods.
When everything done I had 42 lbs hot at cruise rpm and hot idle at 950 rpm at 20 psi.

Plan on using a solar panel on the top of the instrument panel below the big flat windshield to charge the 12 battery that runs the handheld radio and the electric elevator trim and the oil temp gauge on the JMR.
SMH...thats genius man.:cool: I've already assembled these rockers, but I will certainly give that a try on the next one. Thank you!

An 1835 pushes my tube buggy along just fine!
 

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Pops

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Going to paint my buggy with Poly-Fiber green epoxy primer with polished aluminum sides and hood. 1835 cc VW engine with the Bob Hoover mods. Need to visit the auto junk yards for a good set of seats for my old bones.
 

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Pops

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I have to agree. Great little engine. I have built street bugs that made the Mustang and Camaro boys go home with their heads down. Amazing engines.

Guessing , that looks like a 1969 VW Bug body in the video.
 

Dillpickle

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I have to agree. Great little engine. I have built street bugs that made the Mustang and Camaro boys go home with their heads down. Amazing engines."

And they BEG to be unbolted from the humble bug and put to use elsewhere. I had this free 1967 Cushman truckster given to me this last fall, and an extra '74 super beetle that was tossed in with another deal. They ended up mashed together. Kinda fun to drive, and definitely turns heads!
 

billyvray

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Is your buggy from a kit, or did you bend all the tube yourself?
Either way I'm interested !

Going to paint my buggy with Poly-Fiber green epoxy primer with polished aluminum sides and hood. 1835 cc VW engine with the Bob Hoover mods. Need to visit the auto junk yards for a good set of seats for my old bones.
 

ArcticDave

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Going to paint my buggy with Poly-Fiber green epoxy primer with polished aluminum sides and hood. 1835 cc VW engine with the Bob Hoover mods. Need to visit the auto junk yards for a good set of seats for my old bones.

Looking good! It has the lines of an old Chenoweth.
If you're going to run it off road, I would recommend some X bracing in front of the cabin. I did that to mine and it really stiffened the chassis. I can hit something off camber now and the frame doesn't twist at all. See below :)

I have a set of older Beard shorty seats, and they are super comfortable. Comfortable seats are must at my age.

Red Green is my hero! Hahahaha watched him every week growing up in Alaska. His show came on every Saturday on the local PBS station.
 

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TXFlyGuy

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I have to agree. Great little engine. I have built street bugs that made the Mustang and Camaro boys go home with their heads down. Amazing engines.

Guessing , that looks like a 1969 VW Bug body in the video.
Yes, 1969. Bought it in 1974, sold it in 2017. Toga White, the original color. VW only did that color in '69. The car was in mint condition. Custom built engine, but 1650 cc. Rock solid cruising down the highway at 80+ mph. Just keep those valves adjusted.

I'm sure this engine would have ran well in an airplane!
 

Pops

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Is your buggy from a kit, or did you bend all the tube yourself?
Either way I'm interested !

The tubing was a kit but it was very poor. Poor fit and some tubes to short, etc. I build a couple tube buggies back in the 1970's from tube kits and they were very good.
 

Pops

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Yes, 1969. Bought it in 1974, sold it in 2017. Toga White, the original color. VW only did that color in '69. The car was in mint condition. Custom built engine, but 1650 cc. Rock solid cruising down the highway at 80+ mph. Just keep those valves adjusted.

I'm sure this engine would have ran well in an airplane!

My first VW was a 1969 that I bought new for $1868 drive away price.
I built a 1968 VW Bug body on a box frame that I built and powered with a 1972 Buick 215 CI, 200 hp engine. Sold it a couple years ago. Friend of mine built a 1974 Conv on a box frame with a Chevy 383 engine. Looks factory made.
 

Pops

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Looking good! It has the lines of an old Chenoweth.
If you're going to run it off road, I would recommend some X bracing in front of the cabin. I did that to mine and it really stiffened the chassis. I can hit something off camber now and the frame doesn't twist at all. See below :)

I have a set of older Beard shorty seats, and they are super comfortable. Comfortable seats are must at my age.

Red Green is my hero! Hahahaha watched him every week growing up in Alaska. His show came on every Saturday on the local PBS station.

Getting easier in this state to get an assembled title and put it on the road. Also there are back logging roads where I can go almost across the state. Back in the 1970's I ran the pipe buggies on the highways until they changed the law requiring state inspection stickers.
 
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ArcticDave

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Thankfully tube buggies are completely legal here in Arizona. They require insurance and all that, but I can drive anywhere in my buggy...and i do. :cool:

Back to the subject of HVX mods, Pops... have you ever messed with Mr. Hoover's oil pressure valve modification? I did it to this half veedub I'm building, more out of curiosity than anything. You take out the piston and replace it with a steel ball instead. I made a seat out of some chromo tubing for the ball to seal against. Knurled the outside, slathered it some loctite retaining compound and drove it into the bore at the rear of the case. I made the seat long enough to compensate for the height difference between the ball and old piston. Mr. Hoover claimed it resulted in smoother oil pressure regulation.
 

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Pops

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Thankfully tube buggies are completely legal here in Arizona. They require insurance and all that, but I can drive anywhere in my buggy...and i do. :cool:

Back to the subject of HVX mods, Pops... have you ever messed with Mr. Hoover's oil pressure valve modification? I did it to this half veedub I'm building, more out of curiosity than anything. You take out the piston and replace it with a steel ball instead. I made a seat out of some chromo tubing for the ball to seal against. Knurled the outside, slathered it some loctite retaining compound and drove it into the bore at the rear of the case. I made the seat long enough to compensate for the height difference between the ball and old piston. Mr. Hoover claimed it resulted in smoother oil pressure regulation.

No. I do use an adjustable oil control valve at the rear of the case close to the flywheel. This valve controls the high oil pressure limit. I usually adjust it for a top oil pressure of about 55-60 psi.
 
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