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steven wardlaw Samba Member
Joined: January 13, 2012 Posts: 142
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Posted: Tue May 31, 2022 1:44 pm Post subject: Keeping the Judson engine cool |
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I've scanned through several forum post that say the best way to keep an old 40hp with a Judson cool is to change over to the dog house fan shroud set up. With my engine I added a Porsche oil cooler and changed out the generator and crank pullies to increase fan speed. Can the dog house cooler be added without the change to 12 volt generator? Would someone shed some light on the problem for me. Thanks.
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esde Samba Member
Joined: October 20, 2007 Posts: 5969 Location: central rust belt
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Posted: Tue May 31, 2022 2:35 pm Post subject: Re: Keeping the Judson engine cool |
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Yes you can run a doghouse cooler with a 6 volt generator. Use the 6 volt fan, as it has holes to draw air through the generator (cooling). You will also need to keep the pedestal. _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
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steven wardlaw Samba Member
Joined: January 13, 2012 Posts: 142
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Posted: Tue May 31, 2022 5:41 pm Post subject: Re: Keeping the Judson engine cool |
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Will the aftermarket 36hp dog house shroud work with the stale air system and my fan? |
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esde Samba Member
Joined: October 20, 2007 Posts: 5969 Location: central rust belt
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Posted: Tue May 31, 2022 8:14 pm Post subject: Re: Keeping the Judson engine cool |
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You'll have to cut the notch for the stale air thermostat linkage, but everything else should fit. Use the entire 6 volt pulley/ generator/ backing plate/ fan and shim if it rubs. _________________ modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7216 Location: Videbaek Denmark
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Posted: Sat Jun 04, 2022 2:16 pm Post subject: Re: Keeping the Judson engine cool |
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While the swop to a doghouse cooling set up willhelp you with keeping temps down it will most likely not solve your issue. The Judson engines are notorius for overheating and have a tendency to detonating due to generally 3 things. 1. The oil mist shot into the system to lube the supercharger decreases the octane in the fuel. Not a lot, but enough to contribute to an elevated risk of detonation under boost. 2. elevated intake temperatures due to a lot of friction between the vanes and the charger housing. And 3. Wrong ignition timing under boost.
You are actually going in the right direction with the SVA distributor, but I would not be surprised if there is upwards of 12-15Kpa vacum in the manifold under boost. That will result in the distributor not reducing timing enough in relation to the boost, so you are most likely having something like 34-35 degrees of timing at WOT. That increases the risk of detonation a lot because the burn will be at the wrong time in the cyclus, and will also create elevated cylinderhead temps which will be hard to control with just more cooling air.
If the vehicle is "just" a weekend show car the easy way was to take an old 010 or 019 and limit the timing to 28ish degrees and call it a day.
If you want to put some miles on it I suggest that you go just a little bit modern on the inside and as close to old look on the outside. Then you can buy a CSP Pacemaker distributor, black and with black cap, Then it smells a little of fish. https://www.csp-shop.com/en/electric/distributor-csp-pacemaker-bluetooth-905-205-csp400-30204b.html These distributors are 2 D programmable and will also work with 6 volt. You will have to replace the delivered rotor with a low ohm unit and - maybe - your ignition leads to a more RFI surpressed version. (They are out there, and still looking "old".
With this distributor you will then have to tap the manifold for a vacum outlet. Then you can relatively easily program the vacum to work as it should on cruise and to retard the timing a tad when you are on boost.
Finally I would recommend you to modify your front plate with a 2 x 2" hole just over the starter to help the engine get more air. The pre 67 cars starves anything more than a 1200 engine. Cutting the front plate will lower the cylinderhead temps with 10 degrees on the spot.
Hope this helps. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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steven wardlaw Samba Member
Joined: January 13, 2012 Posts: 142
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Posted: Thu Aug 11, 2022 2:21 pm Post subject: Re: Keeping the Judson engine cool |
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Just wanted to add a new photo of the engine bay on the 62 and to let some folks know what I have done to help out the old girl. I added a 356 Porsche aluminum oil cooler, new idler pulley for the Judosn, and changed the oil filter over to an Oberg filter system. I never cared for the old canister filter system. The old canister filter required adding an extra quart of oil and that extra quart would drain back into the motor and put it way over full on the next start up. The Oberg really doesn't require more oil to be added as there isn't any needed capacity needed to keep it full. I did add just a little to make sure we stay at the correct fill level. The flex lines are much better than the hard copper lines that had a problem with cracks from the engine vibrations. |
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[email protected] Samba Member
Joined: June 24, 2015 Posts: 719 Location: Rialto. CA
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Posted: Thu Aug 11, 2022 4:11 pm Post subject: Re: Keeping the Judson engine cool |
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Doesn't the judson recommend to eliminate the choke since a choke is not need in a blower ...are you running a choke seem like it or did you some how eliminated it ...that's why solex 28pci or solex 32 pci carbs I've even heard of a guy using a solex 34 pci carb are used with judson because it's easier to eliminate the choke on those carbs ... |
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Bub Samba Member
Joined: June 10, 2004 Posts: 1155 Location: Central Washington
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Posted: Fri Aug 12, 2022 8:17 am Post subject: Re: Keeping the Judson engine cool |
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steven wardlaw wrote: |
The old canister filter required adding an extra quart of oil and that extra quart would drain back into the motor and put it way over full on the next start up. |
Did you actually find that this was happening? I assumed it would too- but from my experience the canister filters don't drain very much once the engine isn't running. In my 356's and current 36hp (Okrasa filter) the canister is always 3/4 full at least. That's why they have a drain I guess.
No very relevant, personally I bet the Oberg is a better setup anyway- probably takes 70k miles to filter 3qts of oil through the canister. _________________
hitest wrote: |
Had a girlfriend once who shall we say, nearly arrived at the mere sight of a semaphore in action- easy to please she was... |
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steven wardlaw Samba Member
Joined: January 13, 2012 Posts: 142
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Posted: Fri Aug 12, 2022 8:41 am Post subject: Re: Keeping the Judson engine cool |
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I'm still running the choke on the 28 carb. I've never had a problem with running the choke but did have major problems with vapor lock issues. I finally changed out the original style dome top fuel pump for the square top pump. the square top has the check valve that the dome tops did not. Some of the 40hp motors added a check valve into the fuel delivery line but most of those are no longer being used today. After adding the new pump and making sure the pressure was within the specs I have had any of the vapor lock problems.
The Fram canister filter I was using had the return drain at the very bottom of the filter so the full amount of oil in the canister would drain back to the crankcase after running the engine.
I ran the engine about 40 miles yesterday and after that trip I checked the oil temp and was glad to see that all was working well with the old engine. Engine oil temp was around 160 degrees with the air temp outside at around 90 degrees. I'm sure if I drove it harder or added a lot of hills that the temps might have been higher. |
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Bub Samba Member
Joined: June 10, 2004 Posts: 1155 Location: Central Washington
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Posted: Fri Aug 12, 2022 8:53 am Post subject: delete |
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steven wardlaw wrote: |
Engine oil temp was around 160 degrees with the air temp outside at around 90 degrees. I'm sure if I drove it harder or added a lot of hills that the temps might have been higher. |
160 * !?! My oil is 160* before I even start the car! Seriously...160* is almost a cold engine. Mine runs 200-220* in light driving on a 90* day.
240* sometimes....but I know why and I'm not surprised and it doesn't seem to bother it. _________________
hitest wrote: |
Had a girlfriend once who shall we say, nearly arrived at the mere sight of a semaphore in action- easy to please she was... |
Last edited by Bub on Fri Aug 12, 2022 9:26 am; edited 2 times in total |
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steven wardlaw Samba Member
Joined: January 13, 2012 Posts: 142
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Posted: Fri Aug 12, 2022 9:18 am Post subject: Re: Keeping the Judson engine cool |
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My car doesn't have an oil temp gauge and I have to check the temp with an external temp gauge that is inserted into the dipstick hole. Can't say how accurate that really is but I can keep my hand on the oil cooler after it is up to temp. The Gene Berg oil temp dipstick never even gets close to turning on the dash idiot light. That dipstick will turn on the light at 220-225 degrees. |
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steven wardlaw Samba Member
Joined: January 13, 2012 Posts: 142
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Posted: Fri Aug 12, 2022 9:32 am Post subject: Re: Keeping the Judson engine cool |
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I had many issues with a hot engine after adding the Judson and found that my biggest problem was not jetting the carb to give the engine the fuel it needed. I also don't run alcohol added fuel in the car. I'm lucky to live near stations that carry premium non-alcohol fuel. I had to switch to premium with the Judson. the Judson boost pushed the compression ratio up to the point of spark knock on regular gas. Adding a Porsche 356 aluminum cooler did help with better cooling along with pulley changes that increased the cooling fan speed. |
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vwhelmot Samba Member
Joined: May 04, 2006 Posts: 617 Location: united kingdom
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Posted: Thu Aug 18, 2022 12:34 am Post subject: Re: Keeping the Judson engine cool |
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I run a Cab decklid, 010 dizzy and everything else stock. Just made sure it was always adjusted right , had the correct carb jets and the tinware fitted as it should. Never had any issues with temp. |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1466 Location: San Carlos, CA
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Posted: Thu Aug 25, 2022 4:26 pm Post subject: Re: Keeping the Judson engine cool |
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According to Jake Raby, ceramic coating your combustion chamber, valve faces and piston tops will dramatically reduce your head temps. Just make sure to also coat your ring lands. If you don't do this, you may have problems with microwelding of your top ring.
Cheers,
Paul _________________ "I would rather have questions that can't be answered than answers that can't be questioned."
Richard Feynman |
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doveblue3 Samba Member
Joined: March 28, 2003 Posts: 1820 Location: Florida
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Posted: Thu Feb 16, 2023 10:47 am Post subject: Re: Keeping the Judson engine cool |
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steven wardlaw wrote: |
I'm still running the choke on the 28 carb. I've never had a problem with running the choke but did have major problems with vapor lock issues. I finally changed out the original style dome top fuel pump for the square top pump. the square top has the check valve that the dome tops did not. Some of the 40hp motors added a check valve into the fuel delivery line but most of those are no longer being used today. After adding the new pump and making sure the pressure was within the specs I have had any of the vapor lock problems.
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Could you please provide further info on this inline check valve? I had been having what I thought were vapor lock issues when hot (dry incoming line), and switched to the later fuel pump based upon your post above. Although that did seem to improve the situation, it stuck it to me again a few weeks ago after a drive that heated things up to full operating temp. Note that these issues did not happen prior to install of the Judson. It's weird - nothing seems overly "hot" there is just no fuel flow. |
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hcarrera Samba Member
Joined: January 20, 2012 Posts: 1 Location: Houston , Tx
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Posted: Sat Feb 25, 2023 7:24 pm Post subject: Re: Keeping the Judson engine cool |
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Hi everybody
how I can resolve the oil pressure in my judson supercharger 36 hp?
thanks |
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