Oil cooling options...

Well, you'd think that Gene would be trying to sell you an aftermarket cooler if they helped at all since that's his business. He's been doing bugs since about 90 million years ago, so I think I'd take his advice.

My '70 bug has over 400K miles and is only on it's 2nd rebuild with a just stock oil cooling.

I suggest we all keep an eye on the research that Jake Raby is doing. His research is _thorough_ and it will certainly be invaluable to the information available, although I think most of his focus is largely high-performance ACVWs built correctly (that is: Jake's way).

In a case like this consider who is trying to sell you something. Berg could sell you and oil cooler, too, and make just as much money off it. The fact that he's trying to talk you out of spending money on something tells you a LOT.

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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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I can't believe that an external oil cooler (along with the stock cooler) doesn't help a performance engine. But I'm willing to listen and proven wrong, so someone try to convince me otherwise. Until then, I call bullshit.

The additional cooler will help the oil temp. Problem is, high oil temps more often a symptom than the problem.

I have done several long trips in very hot conditions in my Ghia, both before and after adding a Setrab cooler (in addition to the stock cooler). I can say that the Setrab reduced my oil temps quite a bit under similar conditions. On the other hand, that didn't keep me from cracking two sets of stock heads, one set after adding the Setrab.

On an air cooled VW engine, the biggest heat related challenge is usually that of head temps. That is where the most intense source of heat is (the combustion chamber) and the fewest options for dealing with that heat.

If you are in the engine-building or parts-selling business, what sort of temp gauge are you going to push? The one that has the easiest follow-on sale potential? Or the one that will tell the customer he has a problem you don't have an easy answer for?

The easy solution to 260ºF oil is a simple bolt-on cooler. Which is great if you sell such things. The oil temp comes down, the customer is happy and gets to show off all that shiny hardware to his friends.

But suppose his heads are running 350ºF just loafing around town and pass

450ºF north-bound when you put your foot into it. Now what do you sell him? The parts of his cooling system that are missing? Do you tell him to drive slower? Take back that power-pulley you sold him? Tell him his rice-eating engine design can't really take more than 30 minutes on the freeway? Yeah, that'll work.

For most of the kiddies (to use Bob Hoover's term), a cylinder head temp gauge would just raise inconvenient questions.

BTW, if the oil is too hot, the heads probably are too. Knocking the oil temp down with addition cooling leaves the source of all that heat (mostly the heads) in place. I have a collection of ruined heads to show for it.

Max

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Including Volkswagen.

In case you hadn't noticed, the dog-house oil cooler arrangement is an 'external' oil cooler and is even provided with a source of cooling air independent of that used for cooling the engine (ie, the extra width of the later model blower and the scroll that collects that extra air and delivers it to the oil cooler). The system even has its own exhaust ducting.

Putting the oil cooler inside the blower housing has always imposed additional heat-stress to the downstream cylinders (ie, #3 & #4) with most of the pre-heated air going to #3.

The added heat-load wasn't much of a problem for the original 985cc engine but after VW bored & stroked the basic design, #3 cylinder began to swallow its exhaust valve with alarming regularity. By the time the engine had grown to

1300cc the problem became so severe that VW began retarding the timing on #3, originally by 4 degrees. This upset the volumetric balance of the engine and increased its fuel consumption but it also cooled things down a bit. The extra fuel wasn't burned, it was being blown out the tail pipe after serving to cool the #3 exhaust valve. That meant the engine's hydrocarbon emissions went through the roof but in 1965 Volkswagen didn't think Americans were really serious about all that 'clean air' stuff. (And by the time they got the message, it was too late.)

A better fix in the view of hot-rodders was to get the oil cooler out of the blower housing -- and to run a 'straight-cut' distributor. Volkswagen confirmed the validity of this approach when they did the same thing, going to an external cooler in '71.

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Ah, yes. Gene's extensive testing.

Guys starting putting bigger jugs on VW's in the late 50's, originally using the barrels from a Harley or those war-surplus Wisconsin engines. On the later cases we turned the lugs off Corvair jugs and used those.

Bigger engine means more heat. The oil cooler blocked the air flow to the left bank so we took it out. But removing the oil cooler lead to a serious upset in the distribution of the cooling air to the left bank -- you had to put in a plate with a curved lip over your hose adapter. This apparently restored the pressure distribution and smoothed the air flow so that each jug got an equal amount. (The key point here is that with air cooled systems, flow is a function of pressure. Unlike liquids which can not be compressed to any extent, gases are easily compressed. With the VW, reducing the pressure of the cooling air or creating an imbalance in its distribution, usually leads to overheating.)

I've already written about the methods tried & used back then, from heater cores to finned refrigeration tubing. The system I finally got to work -- reliably -- consisted of a pair of war-surplus 'Harrison'-style oil coolers for the Continental A65 engine mounted over the intake of the blower housing. This still subjected the engine to waste heat extracted from the oil but now the heat load was distributed across all four jugs instead of being concentrated on #3 and proved to be an acceptable compromise.

As it turned out, finding a suitable oil cooler was only half the problem. The real trick was coming to understand how and when VW sends oil to the cooler, which in normal operation is only part of the time. That means you need a cooler capable of removing a lot of heat from a relatively small quantity of oil in a relatively short period of time. That dictates a cooler offering a low restriction to flow but with lots of fin area. And that pretty much ruled out using the stock VW oil cooler. It has a low restriction but lacked the required surface area for use with larger engines. Plus, it was heavy and difficult to mount.

The Corvair oil cooler was a close match to the Harrison, as was the cooler VW used on the Type III engine. (The Type III cooler is the best one VW ever made, having 8 fins to the inch. The ones used on '71 and later engines have only 6.)

Suppliers to the Kiddie Trade offered a number of external cooler kits, most based on varioius versions of refrigeration coils and most of which offered too much restriction at low temps and not enough cooling at high because the fins were not bonded to the tubes but simply pushed on. Plus, most were fabricated of soldered copper. Not the good stuff, just plain old fashioned plumbing solder. Subjected to high temps and lots of vibration, the joints would age-harden and leak.

(If you're unfamiliar with any of the above I suggest you find a copy of Bill Fisher's 'How to Hotrod Volkswagen Engines' and give it a read. Although published in 1970 most of the material still applies.)

Having built some large engines that racked up a lot of miles using external oil coolers I was rather surprised by Gene's negative opinion and asked him about the 'tests' he mentioned. His response was to say there was no reason for him to discuss it since I wouldn't be able to understand it.

Which is probably true :-)

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I think most of the problems associated with non-stock oil cooling arrangements are due to a lack of understanding about how the VW system works.

If you install a full-flow oil filter and put a cooler between the outlet and the engine, you need a cooler having a very low restriction. That generally dicatates a big cooler. But you also need a cooler that can handle the maximum heat-load. That means a lot of fins -- a lot of surface area. Plus, the core must withstand the maximum cold-engine oil pressure. Combine those requirements and you're looking at a very expensive piece of goods.

Most opt for a big, sturdy, low-restriction core like the Mesa (or similar). Unfortunately, due to their relatively small surface area, at higher temps the rate of flow thru the core may be so high that not enough heat is removed from the oil.

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The dog-house cooler has proven effective for engines up to two liters and may be improved by using a core having more surface area, such as those from a Type III or Type IV engine.

If you feel an external cooler is an absolute necessity then you should probably provide some method of thermostatic control, either to the flow of oil, such as the valve used by Porsche, or the flow of cooling air, such as using a thermostatically controlled blower.

Since the Porsche oil-flow control valve is a $300 item and its after-market copies are prone to leaks and failure of the thermostat, I went with a blower arrangement.

My solution (for a 2180 in a '65 bus that has hauled a boat down to Bahai de Los Angeles more than once) was to run a large, low restriction external cooler in addition to the stock dog-house, but to mount the extrenal cooler in a plenum chamber having its own exhaust and fitted with a thermostatically controlled fan, an installation not for the faint of heart :-)

Grinding up the grade at El Rosario, the difference between making it to the top or not was to hear that blower kick in and see the oil temp settle back into the green.

-Bob Hoover

Bob, thank you so much for taking the time to share your knowledge with us. This is exactly the kind of information I was fishing for. Clearly, keeping a VW engine cool is not just a matter of slapping on some trick part, but results from a careful balance of factors, none of which happen by accident. Bill Fisher's book is on my list...I'll pick up a copy today.

Cheers, Walt

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You're welcome. But in this case it was mostly remembrances. I wasn't the only guy doing that kind of stuff.

But the key point is that Gene said you couldn't pull the oil cooler without making the engine run hotter. And then Volkswagen pulled the oil cooler and arranged things so it DIDN'T run hotter.... which is exactly what a lot of other folks had done as much as ten years before.

Along with external oil coolers that actually worked there were things like ratio rockers, bigger jugs, case-savers, swivel-foot adjusters, electronic ignition systems, full-flow oil filtration, hydraulic lifters, full time valve train lubrication... all that stuff was running on the streets, tracks and off-road courses years -- YEARS -- before it appeared on a stock VW.

I'm often asked, if these tricks are so kewl how come the asker has never seen them in "..the magazines."

The answer is painfully simple. It is also a Rite of Passage between Kiddiedom and maturity, something the asker has to figger out for themselves.

Magazines exist to support their ADVERTISERS. And their biggest advertisers are the retailers selling junk to the Kiddie Trade. Most of the mods I've mentioned above are not something you can buy, bolt on, and drive off. Most of the really good mods have to be built-in to the engine during assembly. Nothing to sell, other than skill, and most of the good VW machine shops include such mods on their job-tickets. This sort of thing comes under the heading of Old News, at least to real mechanics.

This is interesting -- maybe someone can post some information how to do this. Gets hot here in SoCal and I have a 71 doghouse.

Sure:

Jan

Yup. Bob's answer is right-on. I may be the designated newbie to VW's and mechanics, but I know about how the publishing business operates to serve itself.

Here's how to tell if a "buff" (enthusiast/specialty) magazine can be trusted: if it only provides powder-puff reviews of gear and stays away from in-depth technical articles, it has been purposely dumbed-down to please the advertisers.

I've seen it happen in other fields, where originally useful and informative magazines started by enthusiasts with little interest in business are acquired by large publishers who care only about revenues. The original writers and editors are marginalized or fired outright if they aren't willing to toe the new Party Line (i.e., start helping the advertisers sell their wares). Then "fresh blood" -- hip young new writers and editors who are easily excited by advertiser's claims are hired (another word for those guys is "hacks"). Advertisers can now safely provide their products to the magazines for review, they'll get favorable mention in articles, sales go up, ad rates go up, everyone is happy. The only loser in this otherwise friendly relationship is the reader.

I let Bob slide because I presumed that he was refering to the automotive area, but your affirmation is too general so let me just say 'bullshit'. Not all magazines live to serve the advertisers. Show me your publishing expertise and I'll show you ours (speaking for Molly and myself.)

Do that.

..................Is your magazine available at the mall newstand or at Barnes & Noble? Do your advertisers get exposure to a circulation of lets say at least 25,000 readers per month? Does your magazine get more incoming cash-flow from advertisers than it does from subscriptions? It's clear enough to me that Mike is talking about widely circulated magazines that do indeed follow the model that he describes. What are you publishing John...........'Olde Biker's Gazette' with a readership of 5,000 lifetime subscribers? Do the newsstands turn down your promotional offers for a stack of freebies?

Nah, John just needs to get laid. :-)

Agreed.

Max

Fuck you, Timmie. It's Molly's. Big River magazine. Does everything have to be big and ugly to make you happy? Think it over.

Yeah, Tim can be an asshole sometimes. Like you. Y'all should get along. HAHAHAHA! :-)

....................I wouldn't deliberately try to upset Molly. She's probably got enough problems in her life considering who she's living with. Tell her I'm sorry...........and you can KMA.

timmy

Nice try, Timmie. Take a pill.