VW Engine Oil System / Hoover Mod revisited
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- Опубліковано 25 лип 2024
- I am going to revisit the oil system hoover mod and explain how to do and why I think it's not needed. There is one small mod to the center cam bearing that could be helpful if you use a bigger oil pump than the stock 26mm
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Hey EZ, the way you talk, one would think you had some experience with VW engines, or somethin' LOL Appreciate ya; keep 'em comin; !!
That happens when you drive what you build almost every day for 30 years hehehe
Morning EZGZ! If memory serves me correctly the reason behind the Hoover mod is for increased volume and availability of oil for the top end, you showed part of it being the case modifications. One other important step is to add a couple notches to the lifter grooves. What this will accomplish is oil going down your pushrods at all times to help with valve train life and heat dissipation. There are other parts of the mod that have to do with the rocker shafts and adjusters. This will also increase the time between head rebuild intervals. Robert Hoover came up with these as a way to upgrade the type 1 engine to be more robust for aircraft use and took some design changes from the type 4 and implemented them to his motors.
Thanks for taking the time to make another great video
Thanks for your input. I did the research on the origination of the hoover mod from John Mahers site and thought it threw. I see no need for it on a daily driven VW engine. The lifter mod you speak off has also been around forever and more builders are including it but in reality it is for very high lift old school race cam's that made the lifter oil rings go out of range of the oiling hole reducing the amount of oil going up the rod to the head. On my channel I try to focus more on my offroad cars and daily driver's. As I mentioned in the vid I build my engines and drive them many years which gives me first hand info on what my mods do and the long term effects according to how I drive. It's good to have quality comments like yours to further educate our VW family. Recently I was studying the VW aircraft style engines but that is a whole different animal that generally has a narrow RPM operating range according to the propeller design if I interpenetrated that right. One other point is that airplane engines do not use the VW fan shroud and cooling system which has better control for engine temps.
the Hoover mod was for engines running high RPM for long periods of time. Airplanes. IT was to prevent excessive oil to the left side valve cover at high rpm. Relieving it to the other side of the engine. I agree not necessary for street cars.
Exactly this, not sure what his tone is about, there are reasons for everything...
I always enjoy your videos, learned alot. My current case has a similiar mod. Was lucky the case was line bored once. My previous case some of the smaller oil galleys has pieces of cillicone in there and was done by a reputable shop.
I have known EZGZ for a number of years that what he knows about VW engines, mods, ranges, years etc. he also knows about commercial chillers, centrifugal, recip, screw, etc. Also boilers and all things combustible. He just has a love for the VW and it is a beautiful thing.
As always, thanks for another education lesson. And thanks for taking the time to share.
G'day man Kevin here from Australia.
What a great video I've heard of this mod but wasn't to sure what it was all about .
Now I know you explained it perfectly. Thankyou.
And congratulations on 14,000 subscribers. 🥳
✌ Peace man stay safe and i look forward to your next video.
Love the invaluable information you share, EZ GZ. You are one of a small (and I mean SMALL) handful of Vdub folks I trust on here when it comes to keeping the facts straight. Just the other day I was just wondering if I needed to do the Hoover mods in my new aluminum case before getting the short block assembled (1776 cc for my splitwindow bus). I do think I will pass - case closed.
Another Great Informative Video for us from You. These engines are air and oil cooled. All that is good to know stuff. Thanks for sharing what you have learned over the years. Take Care my Friend and have a great week. BigW;-)
Reason I’ve had it come to my newly built 1776 bus motor is because T2’s run warm at the best of times so the Bob Hoover mod saddled with the Gene Berg mod give the following
Approx 15% more oil to the heads 94% more of the time.
The 15% is achieved by the drilling of the case, widening of can bearing saddles and grooving of rockers and shafts. The 94% is actually 100% I believe and achieved by the modification to the lifters.
The Gene Berg cam gear mod reduces pressure on helical gears and reduces oil sling and frothing. Hope this helps .
Thanks. I've been intrigued by the Hoover Mod and while my case is open and empty, thought about doing it. This explanation gave me useful experienced opinion, and I won't bother! Great video EZ, cheers!
Glad I could help! Not doing it is a wise choice.
Great explanation, thank you for taking the time to do the video.
Excellent explanation. Some people just don't want to leave anything alone.
thanks again, EZ!...another great video WITH explanation as to WHY!...that's the reason i sub...
Thanks for sharing EZ keep the great videos coming ✌️✌️✌️
Good Stuff EZ, love your vids!
Thanks for your support
Thank you for the walk through. Very informative.
Glad it was helpful!
I believe the reason for the mod is to get more oil to the 1/2 side pushrods/rockers. If you are using the pushrod micro squirter mod the added splash lube really helps valve train wear with the free benefit of pulling heat from head.
You are exactly correct........
Thanks for the info and your opinion. I also learn from the educated comments. Such as Tony and Speed. Thanks to everyone for sharing your experience and knowledge.
Thanks for the great info 👍 info! I might just widen the center cam valley just a tiny bit.
.....And,,, I just opened an old case and there was silicone everywhere. "drives me nuts!" Permatex Aviation form-a-gasket plastic bottle with built-in brush dark brown very sticky. Most NAPA stores.
Eventually your going to have a leak -(
Some great discussion on oil topics. Silicone should really be used sparingly on and engine. Excess silicone can stop up oil ports
you seem to miss the point of the hvx mod. it was to get more oil to the valve train, not the cam bearings. you also missed the lifter mod that makes this work by allowing oil flow for more than a fraction of crank rotation. finally, the rocker arm mod is needed to get the oil to the valve springs on the right side of the engine, which was the goal to begin with.
Go ahead and follow that hvx tribe. I know from driving my cars every day with modified engines that the hvx mod is not necessary. If you have spring heating problems your putting a band aid on your elbow when the sore is really on your knee. If you do the hvx mod to increase oil flow your robbing oil from your mains and rods. You will need a larger oil pump. Larger pumps take more HP to turn. To much oil flow on rods and mains will cause unwanted bearing wear. Do the research. Build it and drive it for years then take it apart and look. Or just join a club of like believers and continue building it wrong. You hvx guys don't drive your cars like I do so it really doesn't matter. Create a great day my friend.
@@TheEZGZ your points are well taken and in a land based engine make perfect sense. however, bob was an aviator and also believed in the vw design as a suitable power plant so he addressed the short coming in an effort to create a more reliable power plant for small ac. he also created crankshaft alternators and an adapter for mounting the prop on the flywheel end of the crank. this was before the makers of small areo engines were readily available to the eaa folks. so even though he started the hvx mods for the baja bugs, it led to better performance for the home built aircraft using the vw engines. cheers!
amen and more power to ya. It has it's place but many newby's might think it's the right thing to do. For a everyday car I say caution and not for the faint of heart. Everybody get all excited that they are going to gain something and be ahead of the pack. I say the factory new a thing or two and leave well enough alone. Hvx mod is for the 1 % that have the need and know what there doing. God Bless and No Harm No Fowl. Peace!
Really cool video. Thank man
Learning with every video I watch
Me too!
great explanation,.
More great info. Thanks
Always great info with EZ!
👍 Great info.
VW continued this oil gallery style with the later WBX engines so they felt it was not a big issue.
My understanding is the benefit of this mod is when the engine is run at continuous higher revs.
The stock oiling system is adequate for the lifters, rockers and shafts under normal operation in a car, but when used in an aviation application it is not.
Many of his other mods are of more benefit like oil grooves in the rocker shafts and joining the grooves on the lifters.
One other viewer commented that his newly purchased case from Autolina had the oil galley drilled. Also, VW jawbreaker bought an new aluminum bubble top case that came clearanced and all 6 of the main 12mm main bolts were shufflepinned. I love all you guys that throw in your experience and knowledge to help our group of VW lover's
@@TheEZGZ All of these mods absolutely improve the platform, the question is are they actually necessary?
If you're building a screamer stroker engine and plan to drive it like you stole it then the hoover mod is something you should probably do.
There is no right or wrong answer, only what's best for your application.
Brilliant. Extremely helpful video. I have been looking for information on how the oil system works. I especially appreciated the part where you showed us the little bypass for the oil at the cam bearing at the front of the case.
One thing I have been having trouble with is figuring out how the oil gets back into the block after it makes it past the crank thrust bearing near the transmission. I see the inlet hole but my AH block is machined without any other holes for it to return. I saw your other video where you told us to be careful not block that gap with engine sealant but mine is blocked from the factory. Have you ever seen this before? Thank you.
That's not an inlet hole it's the drain hole and it's up off the bottom so some oil remains there for the next start up. The oil is supplied from the rear main journal located under the rear main bearing.
HEY HOW DOES THE BAFFLE PLATE GO IN ?
Hi EZ. I'm looking for information on the plug that is just to the right of the crank near the dip stick. It appears to close the hole made when the factory machined an large return oil path from the cam gear area. I have spent 2 days on the internet with nothing found. I have one that is threaded in and has an Allen wrench center. Is there a name for this? Are there replacement plugs. What size are the threads? Thanks in advance. I have enjoyed your postings.
Confused wether as21 s or as41s are harder alloy
Great info! What size pump do you run with a full flow system on a 2 liter street motor?
26mm
Is the 110 camshaft a small step up from stock in a 1600? I want to go with a larger than stock Cam. But don't want to go too large for my stock 1600 with dual 34 mm carbs. What would you recommend?
you might consider Ratio rocker arms. That way you can always go back to stock without splitting the case????
Waw😍,good job
EZGZ love the video
Nice Explantion , I never Knew VW did it at one Time , Yeah Not all mods are needed or Nesecerry
Thank you!
I see your point on the extra mess created by added oil return around the cam gear but the grooving of the lifters to allow more oil to the rocker shafts to allow cylinder head cooling to be improved ..do you warrant this mod?..
Why do you need to improve perfection? Why do you think VW left it out? That's like putting a bandage on your elbow for the sore on your knee. If you have overheating problems then you need to find the real problem and fix it.
Here's a question for you. I'm about to build a VW engine. I want a stroker with some displacement for power, and keep the rev's down. My understanding is the longer the stroke the more side pressure it puts on the cylinders. In your opinion, what is the longest stroke you would would go with if you want it to hold together for a long time? Thanks
No hesitation on my part. My best engine for a daily driver with good power on pump gas is a 78 storke X 90.5 bore. Stock valve heads, a mild cam, dual carbs, stock heater boxes and no bigger than 1.5 header style exhaust. Cast piston's are fine, counter weighted crank with lighten flywheel, stock length rods ( stock stroker rods or aluminum H beam stroker rods) Total seal piston rings, full flow oil system with filter using a 26mm pump. If you go with a new engine case (aluminum or mag) maybe a 1.5 deep oil sump with professional rotating parts eng balance. It will make good power foreeeeeeeeeveerrrrrr.
Dog house cooler with thermostat and stock air flaps goes without saying along with all the rest of the stock engine tin. That's my theory and I'm doing it in my Baja every day. AMEN
@@TheEZGZ Thank you EZ, I really appreciate the advice. The 78 x 90.5 has been on my mind, though someone said AA has new 92mm thick wall that are the thickest of any (4.75mm I think). I figured displacement is better than high RPM. It's going in a rail buggy, so the 78 x 90.5 is probably more than ample, and if you're putting it in yours, with all your knowledge and experience, that's good for me. Thanks again. Would love to spend a weekend picking your brain, lol.
I totally agree. People forget that designers of these things are not motor mechanics but highly educated professional engineers. They make every hole for a reason they size every hole for a reason they send a certain amount of oil to each
bearing for a reason. If you are planning to race the thing OK , knock your self out but Air cooled VW engines were never
designed for that.
Well said!
How do I know what engine I have in my airplane it's a VW motor. I would like to know the CCS if it's 1800 or 2100 or whatever it might be
You have to take off the head and measure the bore and stroke and CC the head to know for sure. That will also allow you figure out the compression ratio.
There are just to many aftermarket parts available to know how it was built. Its a airplane for crying outl-loud.
I'm working on an unconventional VW engine configuration to be used on
a Gyrocopter. It's going to be a duplicate of the engine used on the
gyrocopter from the movie "Mad Max 2". There are very few photos of the
gyro that can be used as reference but I have enough information that
I can take some educated guesses. The area that is giving me some
grief, and I hope you can make some suggestions, is the intake manifold.
The engine as used in the movie appears to be a single port 1600 and
uses a magneto, no generator stand, standard fuel pump, a modified type 3 oil filler, custom
straight exhaust, external 4-pass oil cooler and a Stromberg BXV carburetor (weird right?).
Anyway, I can see that they turned the intake manifold 180 degrees around and have
some form of squarish carburetor adapter that the intake manifold goes in to and
the carb sits on top of. The carburetor has a cylindrical custom intake filter assembly
on top making the carb sit rather high. The intake manifold does not have any
heat riser attached and therein lies my concern. Since there is no heat available
from the exhaust and there is no electrical system installed, how is the intake
manifold heated in order to reduce the possibility of icing or condensation?
Since no real close-ups of the engine are available, I have to make a guess as
to how to heat the manifold. The only way I can think of is if the "box" that
the intake manifold goes into and the carb sits on is heated by passing the warm
engine oil through it and then to the 4-pass oil cooler. Do you think that
warming just the "T" junction of the intake manifold would be sufficient to prevent
icing and condensation? Is the oil hot enough to do the job? I've never heard of
anyone using hot engine oil to warm the manifold before so this is uncharted
territory.
As a side note, there is a "Mad Max" museum in Australia that is suppose to house
the original gyrocopter from the movie. I contacted them to see if they'd send me
some photo's of the gyro but they refuse to reply. The photo's I can find of this
gyro in their museum is NOT the original. The museum version is a dual port with
a generator stand and generator as well as a horizontal standard VW oil cooler.
The dual intake manifold does go to a "Box" which looks original, but I can't see
any real details to help me.
Sorry for being so long winded but I thought with your experience and "experimental"
nature, you might give this problem some thought. It's my intent to construct a
functional and working Gyro engine identical to that used in the movie and install
it on my current gyro that's using a very expensive Rotax 503 DCDI engine (I hate 2 strokes).
Anyway, thanks for your time and any suggestions would be greatly appreciated!
Sincerely,
Michael Sohnly
Renton, WA
(Virus central, USA)
Generally speaking if they made the movie in warm summer temperatures and low humidity there would not be as big a problem with fuel Icing. You have to be much safer with an aircraft engine.
Stock VW intakes had the exhaust heat at the Tee in the manifold and of course as the engine RPM went up and down so did the exhaust flow. They also used summer and winter air inlet flaps on the oil bath air cleaners to pick up heat near the muffler at lower RPM. So by now You should be getting the concept of not relying on heating the fuel mixture after the carb but also /and/or preheating the air before the carb. A word of caution: VW engines are famous for vapor lock and boiling the fuel in the float bowl causing the engine to quit on hot summer day's. NOT a good thing from the air. Fuel injection fuel systems are less prone to fuel icing.
There are established company's that convert VW engines to 2 cylinder operation and have Magneto's and fuel systems.
www.flight-mechanic.com/carburetor-icing/
a6141.americommerce.com/
www.aeroconversions.com/products/aerovee/index.html
Michael-- are you documenting your gyro build? I'd love to see it!
Hay ezgz do you like the total seal rings they have no gap
Yes, it's just for the second ring groove. I've used it on 2 different engines so far. $100+ dollars and throwing away a perfectly good kind of sounds crazy. The first time was over 20 years ago on my 2110 build that had 9.5 to 1 compression. That made 170 psi compression on all 4 cylinders for years and years. I just freshened up that engine with a new engine block and lowered the compression to 8.5 to 1 . I just honed the cylinders with a standard grit cylinder hone and slapped it together. All 4 cylinders go 160 psi after the build. Not saying I recommend doing that but tells me that it's a good product. Not even saying I would do that again. I guess if you have the extra money and it makes you feel better. Do It! Probably makes more compression for longer that stock.
Friend greetings from Paraguay ... what kind of drill did you use? Long? And width.
I bought a 3/16 by 12 inch long standard twist drill. I don't recommend doing this mod. IMHO It could have easily been done at the factory but they did not do it. If your not having oiling problems and wearing out valve train on cylinders 1 & 2 Why open it up? Your oil pressure will drop because you'll be sending more oil to that side and that lowers the level in the sump.
Where did the Hoover mod come from? Was it someone that used ACVW motors for aircraft??
that's right!
Food for thought, that's somthing I wouldn't do.
I'll have to look up your Vidio on the EFI, have been reading about the new Hollie EFI, (to late for me though, I've just bought a new carby.
Where can I find a gene berg “blue book”
No idea
Hey EZ I’m heading back overseas soon any chance I can talk you into building a motor. I want to drive my bug when I get back.
Nope, Nobody could afford to pay me for the care I put into building each of my engines. That's why I show folks how to do it themselves. Then when something goes wrong they can't blame me. LOL Hope all goes well overseas Thanks
TheEZGZ thanks well it didn’t hurt to ask lol
I would like to ask your advice please. I have several questions on Cam and crank gears.
I have a new Aluminum Auto Lina case, and built an engine with original cam and crank gears (German) The engine makes a noise that goes away when grease is smeared on those gears, and comes back when the oil washes it away.
1. Does anyone make matched gear sets? Hobbed the same?
2. I imagine I can buy a NEW stock grind cam without the gear, and bolt on the cam gear from this matched set correct? I am only looking for stock performance, nothing more.
3. Since this is a highly modified case. (clearanced, webbed, pinned and dual relief) and am using it in a stock configuration. Single port 1600 cc. I assume I can buy the Gear set/cam mentioned above with a ''dished'' feature for the ''new style'' bigger dual port oil pump. correct?
Your response would be greatly appreciated..thank you.
German gears mean nothing because of all the wear. During production the bore of the crank and cam varied. VW made 15 different aluminum cam gears to compensate for this. They vary in pitch from + 1-7 and 0 threw -7. Your new Autolina case falls in there someplace. Only the -0- gear is now made. You have to find a used one or run it in with valve grinding compound or use straight cut gears which make noise. I explain all this in all my engine build video's which you need to watch. You also need to be careful of the crankshaft thrust at the flywheel end and custom fit the camshaft thrust bearing on the cam gear end. Every engine building book explains this in great depth. GET ONE. Do Not trust your instincts or trust what you see on the internet. If you don't follow the correct tolerances and torque things down correctly your engine won't last. Don't forget Zinc in what ever oil you use and do the proper 20 minute cam break in.
@@TheEZGZ ok I will look more closely at your videos.
Yes I understand perfectly about + and - of the hobbing on the cam gear.
I was assuming this was done to match differences in the crank gear. Hence the matched set question. However you have said differences in the cases was the reason for the + and - of the cam. Ok...now I can understand.
Because,... my cam and crank gear came from an original engine....with a rotten case. (Moisture)
I’ve put together several VW engines, and am a maestro mechanic. ASE certified, so I fully understand tolerances.
I only got back into this recently.....last build was in the 80s. Back then it wasn’t unusual to get original German engines that had not been boogered with. So, simply splitting things apart, new bearings, an oil pump....seal stuff up and your golden.
It looks as if it’s going to be hit an miss with this auto Lina case.
About building engine books....yeah, I understand quite a bit about that, and have a few. However the only thing I find in them is hit and miss about how the cam rides. Weather it hops out of the journal or not.
Wolfsburg is the only place that sells + or - cams. Oh, I forgot. I’m only interested in making stock horsepower....it’s why I said cams, and not gears.
I guess I could order all 14 of them and find the one that fits the best...ha,ha,ha
Straight cut gears are great.....BUT here’s the rub....you can only buy stock cams with aluminum helical cut gear riveted to it.
Straight cut gears are for bolt on applications. And with that you can’t get a stock lift and duration.
Probably what I am going to do is buy several used stock lift cams and just find the best one.
Thank you for your response. Bet your bottom dollar, I am going to check out your videos carefully. 😀😀😀
@@OkFixer Why not use the valve grinding compound and rotate the crank and cam until it loosens up. Then clean and final assembly? You can grind off the rivet head, punch out the rivet, then drill and tap for bolt. You may have to grind down bolt head to clear oil pump. We do that all the time for performance cams with 3 holes. Good Luck with your project my friend.
@@TheEZGZ thank you
new autolina cases have it