Fan Shroud/Engine Tin

I'm thinking about replacing my fan shroud and engine tin.
The current set-up I have is a cheap Taiwan chrome plated fan shroud with ill fitting chrome plated engine tin.
I have an oil cooler adapter plumbed to an external thermostatically controlled oil cooler/fan system.
Jake Raby mentioned "a certain 36HP aftermarket shroud took the cake! it beat everything else, even stock and 3 Porsche 911 systems!" -
but Jake is unable to reveal the manufacturer, as he's currently trying to sell his test results to the manufacturer.

Any recommendations for a good source of engine tin/fan shroud will be appreciated.

Thanks

Dave

Has Jake said when his new T1 shroud will by ready?
Ron

Ron, I think Jake was testing different aftermarket shrouds currently available.
He identified one that worked particularly well, and is attempting to sell his test results to the manufacturer so they would be able to market their product with Jakes endorsement.
Check out the post "Retrofitting thermostat and vent flaps in round shroud" for more details.

I tested 14 different systems. Included in this was 3 different stock shrouds. All systems were tested with 3 different drive ratios also.

The certain 36HP shroud that I found to be the best is now in a legal battle to try and figure out who designed it first.

I plan on buying them and re-seling in the mean time, but it may take a few months to do so due to the circumstances.

I'm still convinced that the OEM dog house shroud with thermostat and flaps working is best bet. Would seem to me that metal dissipates heat better than fiberglass anyday --- at least from experience with electronics. Would be interested in seeing how OEM shouds did in Jake's testing.

Hey Jake,

For us cold country people in New England and parts further north.

Could you try a test with this as yet un-named shroud with retrofitted thermostat vents.

I believe the engine warms up better and produces better heat in those 40 F and lower days with the thermostat.

from a MassIVe envious speedster owner
Eric G.

Gregory,
The shrouds don't get hot.. They don't need to dissipate heat.

Next winter I plan to work with getting the engine up to operating temperature with some testing in my car.

Keep in mind that so far I have found FIVE different stock shrouds, all that are doghouse! They all are different internally and cool differently! Proven.

Jake: How's your Dad?

Gordon

Thanks for the update Jake,

Can you put me on the waiting list for a shroud?

What about cylinder covers. As I recall, you mentioned the importance of The "spark plug vanes" being VERY important to cooling, any reccomendations?

Thanks

Dave

I'm interested in knowing if anyone has used a "Center-Mount" alternator post and Fan Shroud combination in the past. My car came with that setup, but I'm not finished yet, so no data. The engine is 1954cc with dual off-board oil coolers and fans. The centermount system looks way-cool, but I hope it's functional enough to do the job. Any feedback??
-Tim

Yes I used a center mount in the testing. second worst thing we tested. The right side plenum is too large and left side is too small to correctly handle the radial airflow. The right side of the engine ran 200, and the left side ran 400- biggest splits of all the testing.

My Dad is back home and doing well, thanks for asking. He was on the tractor all day Monday- good as new! What a turn for the better.

to get on the TI DTM mailing list email info@aircooledtechnology.com

Jake, glad to hear your dad is doing well. Welcome back. Eddie

Jake- please forgive my ignorance, but are you saying that the unnamed shroud (which I assume has the configuration of the so called dog house shroud) performed better than the 911 configuration(like the Bernie Bergman "911" shroud)?

The 911 systems have not lived up to their advertisements so far at all.

Since some of my testing has been revealed I have had atleast 50 emails from guys that are experiencing problems with individual cylinder heat issues, and they all have the same characteristics, just like my testing showed.

The stock doghouse is the easiest and cheapest way to go, and very effective.

Jake,
Thanks for the feedback, as requested. I don't know the scope of your experiments, nor the specifics, but I'm now wondering what to do about the centermount system. With this big of a motor, will the oil coolers be enough to 'regulate' the temperature differential that I might see? I guess I'll buy a couple of thermocouples and TRO to check the results myself, but if you have any more to add ...
-Tim

Oil coolers do not cool cylinder heads! Oil temps hardly have any effect on head temps at all. They are so separate its almost scary!

Buy cylinder head temperature gauge and install its sender on the #1 spark plug... run the car up the road at 75 MPH for a given distance... Go home and swap the sender to the # 3 cylinder and take the same trip... You will have completed your own test and you will see just how what the shroud can do for even temps. An unevenly heated engine is a poor running engine!

Remember, an oil cooler does not cool the cylinders or heads. Head temps are fully controllable with engine design coupled with a shroud that correctly positions the air in the most crucial parts of the engine- nearest the exhaust ports on the heads in my findings with shroud design.

My testing took 3 solid weeks, 500.00 worth of fuel, and a purposely built engine. It was taken very seriously and a 4 person team was dedicated to it the entire time. Ultra VW magazine from the UK is covering it in a series of comprehensive articles in the next few months.

If in doubt, use stock cooling tin! (atleast till the TI DTM is perfected)

I would recommend a 1973 type 181 shroud (no fresh air heat outlets) with genuine VW cylinder/head tin (with spark plug air deflectors).

I'm going to order a dual head temp gauge from Westach, so I can monitor #1 and #3 at the same time. I'm running a Bernie Bergman 911 shroud and I've got the funny feeling that I'm not going to be happy with the results.
Ron

Ron, with the 911 shroud the hottest cylinders are #2 and #4 i every instance I have seen. The axial fan blows air back and cools 1-3 fairly well, while 2-4 bake. This is why guys think that the 911 is so good, because they base its preformance on 1-3, which are conventionally hotter always. The 911 changes all that and as soon as you use 12 sensors on the same engine simultaneously you'll see that 2-4 hurt badly. #2 has been over 100 degrees hotter than any other cylinder with one shroud I tested. Its positioned in a fashion that puts it under and behind the fan and since the axial fan makes a ton of CFM, but with low pressure there is not enough force to help the air find its way to that path.... I have been working with my 911 shroud mold a bit and can say that many of the shrouds are too LARGE, when compared to the stock 911 shroud. I'm trying to make a very complex version of the 911 system actually work, but its not being easy.

BTW, as soon as any radial fan set up was reinstalled on the engine the #2 temps went right back down again...

George mentions a 181 shroud, but in the test work there was little gains from one, not even noticeable when compared to any other doghouse shroud, the only benefit is that it incorporates a scoop inside the rear of the right side plenum like the 1971 only BUS version of the doghouse. This gets more pressure to the cooler cavity for the oil cooler.

I have studied this stuff somuch that I have almost went crazy...

TI DTM is *almost* perfected! Gimme 6 more weeks and it'll go back on the dyno and out of the car!

Jake- Your information is most valuable and appreciated. It is so refreshing to get information that is based on exacting testing procedures rather than opinions. I was very close to ordering a 911 type of system for my 2.4 engine. Now thanks to you, I will not use the 911 setup ut instead will purchase your product when it becomes available.

David,
you don't have to have my DTM, and I wasn't trying to persuade you into buying one with my post.

The 911 shroud works fine on a 911 engine. 911 engines have different cylinders (Nickies)and way more surface area..

In other words stock tin will be sufficient, and the DTM (when perfected) will be an update..

Thanks for the info, Jake. I'll try putting the sensors on #2 and #3 for a comparison.
By the way, is the DTM going to have heater holes?
Ron

The DTM can use heater outlets...

But you are better off with a gas heater...

Ahmen! 3 of my 5 daily drivers have them.

A gas heater would be nice, but I've already got the big heater boxes, and they've kept me warm enough, even when the temperature drops down to near freezing. My biggest problem is the drafts coming in from around the side windows. I may blow the wad and get Henry in install a newer style top and hardware. I'll have to replace my old top fairly soon anyways.
Ron

Jake; was that battle resolved? And finally, will you be able to let us know who's the manufacturer?

The battle was never resolved.. AND the MFR would not pay me anything for my testing of their shroud, so I refuse to help them.

Greg, if you're running a larger engine, why bother to alter the dog house with a type 4 cooler as you'll need an external cooler anyway.

As I recall, Jake's extensive testing reveled, the thermostat flaps reduced cooling efficiency - Gene Berg said they improve the cooling.

Maybe Jake can clarify this.

George Brown, are you using the thermostat flaps?

They're not as easy to work around as the 36 hp type doghouse shrouds, but I think VW knew what they were doing when they created the cooling system.
My preference for my newest project 2 litre type1, 9:1 compression, dual 44 webbers,follows:
Doghouse (leave as is), (leave as is) fanshroud with thermostat flaps installed. (leave as is), (leave as is) Cyl covers, and early deflectors (under cylinders)
(Preferable to have thermostat operate flaps but flaps set full open is OK.)
doghouse parts of fan shroud altered to accept 914 or 411 bus type cooler.(read a couple of rows wider)
Welded, balanced fan
Any NON-powerpulley crank pulley and stock dia alternator pulley.
Aluminum housing full flow oil pump. Desired oil pressure = around 40 psi at turnpike speeds w/ 20/50 oil temp at 210 degrees.
Add external cooler(s) if needed.
I think wider cooler and sealed engine compartment will be adequate to keep temps reasonable. Oh yeah, the firewall has the air intake hole at engine fan intake.(Fiberfab body)
Greg B

David,
I use the oil pump that routes the oil through the front cover for the full flow oil filter system. The filter attaches to the engine via a bracket bolted to the exhaust header.
I can add oil cooler(s)by splicing into the filter system if I need to, however I'd like to be able to Remove and Replace the motor without the hassle of undoing oil lines and all that drippy mess. (And quick connect oil lines just aren't in the budget)

I've used this same system in a VW bug with a smaller motor without problems. The TypeIV cooler should be large enough to handle the type 1 motor so I'm going to give it a shot.

I like being able to swap motors from Bug to Ghia to Speedster without too many changes.

Greg B
PS
JAKE R. Feel Free To Jump In Here. You've done the tests. When you have the mystery 36 hp shrouds available. Sign me up for 1 if they're better than what I've described here. :-}

I'm under the impression that the thermostat flappers installed, stock OEM fan shroud and non-supertin (I'm using the flat ones that were used pre dual port heads)deflectors under the cylinders and OEM dual port tin with the directional vane near the intake was about as good as it gets using type 1 configuration tin*. (OEM or Aftermarket)

*
I'm not talking about DTM or Center shrouds or 911 fans or anything other than type 1 style sheet metal

"so I refuse to help them."

BUT . . . would you be willing to help out a fellow VW guy havin' a little trouble deciding which shroud to spend money on?

If yes, please send an email/PM and give me a heads-up so that I don't piss away hard earned $ and lunch a nice motor down the line.

I won't tell a soul, my word! Best yet, I'll be in your debt . . .

Thanks,

TC

TC,

why not go with the DTM, I bought one - the product is beautifully made.
I'll be installing it later after Henry at IM begins selling their new air conditioning compressor bracket.
The current compressor bracket I have bolts to the fan shroud for support which can't be done with a DTM.
In the meantime, I'm using a 71+ OEM shroud.

You may want to call Pat at CB, and ask what shrouds they're using.
One of the complaints I've heard regarding the aftermarket shrouds is the spot welds break causing an irritating rattling sound.

I bought an original 36 horse. I pretty much have the flaps installed and will end up welding the dog house sheetmetal onto it. I just chopped up a later shroud and it looks pretty easy. I thought that I would even mount some outlets on the rear side of the head tin and use my dual out-let Type II fan to provide additional cooling air via ducting. Otherwise, I'll use my base plate adapter with a top "cap" and remote cooler/fan set-up.

I only want the engine to look different enough to be confused for something Porsche related, it doesn't have to exactly mimic a 356 engine. The fan shroud will be lost among all of the other details.

SCAT makes a very good aftermarket fan shroud - other than OEM factory, it's the only tin we use. The fit is about the best you will find, yet you possibly may need to trim / file a bit or screw the tin in place. The down side is the finish (even their powder coat) is not that durable. We usually order our tins cad. plated & have them powder coated locally.


On a side note since you mentioned having chrome plated tins - it is NEVER a good idea to have the chrome plated tins on an air cooled engine - the chrome tins retain heat & do not work well for cooling. Because of the design of the engine compartment, cooling is already an issue with the speedsters.