Some of my experiance with fanshrouds for type 4 engines

Sven-Olof Brorsson · Post by **Sven-Olof Brorsson** » Fri Aug 29, 2003 4:05 pm

Over the years I have tried some fan shrouds for the type four and I have seen some testing going on here so I thought I could put up my own observations. First of all I live in Sweden with a not so So Cal type of climate, but it can get hot during July. We also have access to good lead-free 98 octane (RON) gasoline. I have used the shrouds on different engines like 2 liter with ported heads, IDF Webers and BAS exhaust and two 2600 cc full on street and race engines, at one time also used with nitrous oxide. I used VDO oiltemp and headtemp gauges (reading bellow plug but later modified to mount to head directly) to monitor the results. All tests being done in real life traffic situations or racing. Oil cooler is a 96 Mesa cooler mounted directly bellow the transmission in air stream and no electric or other fan of any type are used on the cooler. Oil is fully synthetic (Mobil 5W-50). So here are my results:

I have used the BAS/FAT/German Auto center mounted fan type and when I made some cooling tin to fill in the missing open portion of the enginebay, for it to seal of the heat coming from beneath I got away with very good results. Trying without decklid, lifted decklid on top or bottom and modified with Cabriolet louvers didn?t change the temperature. Actually we had to have the engine running between rounds when racing it on the strip to keep the engine warm enough........Not even Nitrous use affected the oiltemperature but head temp was going up a bit, but not to a risky point.

I then changed to the CSP conversion with fiberglass cylinder/head covers and a Scat non-doghouse shroud. Fitting is good, although I had to make my own tin for sealing up the engine bay this time too, you can't have it all

.... Anyway I received the same good results with that shroud too.

Basically that concludes the two options as equal or near equal at least. I prefer the CSP kit as I can combine it with a Berg shroud mounted linkage.......So to continue the testing I went for a thinner fan from a 25 hp engine instead of the previous Super Beetle model being used.....no changes to the heating efficiency. So I thought, why not raise the compression to 11:1 instead of 10:1....still no problems to report. By the way, I use a power pulley sized pulley and an 55 Amp alternator. I think that both shrouds are OK as cooling devices and efficient enough for street use in the enviormet I live in. The engine in it self is efficient in cooling as it can take the high compression ratio. Stock heads seem to cool efficiently and the same goes for the 103 mm cylindres used as long as they have been braked-in properly (ring sealing and corse honing of cylinderwllas). The change of fanwith and use of power pulley sized pulley did not effect the cooling efficiency of the engine in a negative way. On a small note, we have the same set up of cooler, pulleys, fans, oil, shrouds etc in two separate cars. I tried it during a warm day a few weeks ago and after driving constantly for more than an hour and then end up in stop and go traffic for at least 45 minutes with no heating problems except for the carburetors taking up heat and vaporizing them....... The next engine I am putting togehter (74*103) will have a stock cooling system and we will try it with a stock tin and fan (trying diffrent numbers of blades on the fan).

Anyway, these are my notes on my simple cooling solutions that I have been using over the years and to end the input, I think cooler position, jetting of carbs (IDA:s), exhaust efficense to transport heat and the well design heads are the key components.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri Aug 29, 2003 4:46 pm

Great to see that you did some testing as well. Have you ever tried the DTM style kit that I now offer? Comparing cooling systems takes alot of memory and effort. Till I did my testing I would have never dreamed.

Plastermaster · Post by **Plastermaster** » Fri Aug 29, 2003 8:01 pm

I think Jake has really taken this cooling thing about as far as it can go with what is available.
The T4 is designed to cool better than the T1, and with proper configuration can be pretty forgiving even in a high output engine. I gather that it isn't too hard to cool the engine "reasonably" well with alot of the systems out there and not cause the engine any real damage for many miles. However it doesn't necesarily end there. If your goal is optimum performance with proper warm up. There is alot more to be had with a well designed cooling system...like most other parts of the engine.

After going for a drive, I got to thinking, this post doesn't have much to do with Svens info. and its kind of early to get off topic, so I want to thank you sven for Sharing your findings. It might not be laboratory controled testing, but the real world experience is valuable also.

Ron

Sven-Olof Brorsson · Post by **Sven-Olof Brorsson** » Sat Aug 30, 2003 12:02 am

Thanks for the comments. Engine that I have in car is a real HP engine making power 200+ hp. I never went for the 911 style as they first seamed to expensive for me. I have now access to two 911 systems but I don't consider it necessary as I don't have a cooling problem as of now. Test has been done over years, not in a test environment but in real life. I don?t think it's necessary to have access to a laboratory as I am only a user, not a developer. I have torn down my engines and measured them after years of use and I see no defect coming from lack of cooling.

Plastermaster · Post by **Plastermaster** » Sat Aug 30, 2003 9:08 am

I'll have to check the systems out that you refered to . I guess the CSP is on their site. Do you have links to the others? I wasn't aware that there were any non 911 type systems other than DTM and Cali conversions.

Thanks
Ron

Post by **Tom Notch** » Sat Aug 30, 2003 9:37 am

I find you post interesting, Sven. I an going to put a stock 36/25/40hp fan shroud on my 2382 wasser cased T1 motor and use the 40hp fan (unless I can find a whistleing 36er) and weld the fan together. I also will be using a smaller pulley like you, but not sure if the power pulley or the slightly smaller 5 1/4". One advantage is my engine has aluminum barrels. This is not intended as a street engine but should be streetable enough.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Sat Aug 30, 2003 11:33 am

There ya have it......He is in Europe, has a 200+ HP TIV and doesn't have 911 cooling.......

You are right the 911 seems expensive, and it is ESPECIALLY SINCE IT DOESN"T WORK!

Bobtail · Post by **Bobtail** » Sat Aug 30, 2003 3:32 pm

Does that mean you'll be using 103's then Jake

Seriously tho' , given the exploding fan situation I presume all yours will be welded?
That would be my major fear.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Sat Aug 30, 2003 3:52 pm

Not all will be welded.
I have blown one fan in a DTM conversion, thats all...The welded fan is an option that we do have for the stage IV kits..(the only kit that includes cooling fan and etc.

I'll be using 103s, but only if they are Nickel Silicon Carbide plated Billet Aluminum.......

With the cast iron slugs I have "Been there, done that and have the head leaks to prove it!"

NextGen · Post by **NextGen** » Sat Aug 30, 2003 6:54 pm

Plastermaster the CPS shroud is the Cali style in kit form. Actually all it is, is the 36 hp T-1 fanhousing with doghouse and he also sells the pulley and uses fiberglass cylinder covers, similar to Sharpbuilts T-1 style kit. That's why in the manual I say if you don't want to or do not have the ability to built it all yourself you can purchase things like the covers and gen/alt stand from CPS or Sharpbuilt. Actually I bought my sealing tin from Mike Sharp and it fit perfectly . Later I traded some stuff and got Mike's crank pulley.
Joe

Sven-Olof Brorsson · Post by **Sven-Olof Brorsson** » Mon Sep 01, 2003 2:40 am

The CSP kit can be found on http://www.csp-shop.de/cgi-bin/shop2/sh ... 1086516937

Power pullys lower the fanspeed and therefor act as a problemsolver for blowen fans. No need to weld..or at least that's what we think so far

On a note, we still have to blow a fan to pieces of the T1 version but we blew a T4 away.......

If the 103 cylinders leak where they seal against the head than I would suspect it to be a cylinderhead problem not a cast iron cylinder problem. Going to a aluminum cylinder with the same dimensions would create the same problem as the head in it self collapses. I weld the fins (boxing) by the sparkplug hole, about 40 mm of weld per cylinder. I can only tell whats working for me....

Frallan · Post by **Frallan** » Mon Sep 01, 2003 4:51 am

Thats why I used Scat split ports for many years and no leakage on my 103's.
Not that I would buy Scat heads again for other reasons but cylinder leakage was not one I have had. Furthermore as I run with boost today, I am running "mechanical seal" with two small grooves machined in the top of the cylinders. They make a nice seal but there are some drawbacks as to 1-2 aftertorquying's are needed and if I change the cylinders, I will not get exactly the same mating surface with the head.
The tolerances of the machining of the seals are not excatly the same.
But this was not the main topic........sorry.

Wally · Post by **Wally** » Mon Sep 01, 2003 4:57 am

Sven-Olof Brorsson wrote: If the 103 cylinders leak where they seal against the head than I would suspect it to be a cylinderhead problem not a cast iron cylinder problem. Going to a aluminum cylinder with the same dimensions would create the same problem as the head in it self collapses.

Sven,
As I understood, it isn't a cylinderhead problem, but the steel 103's make it become a head problem: the 'problem' lies in the poor cooling abilities of the big, poorly finned, steel jug: The alu cylinders cool much more because of a the 3x better thermal condutivity of Aluminium, thus giving less residual heat to be transferred to the head. An 'optional' Nikasil plating gives less friction, thus even more so contributing to a cooler cylinder.
A cooler cylinder has less of a expansion difference with the head, more so, because an Alu cylinder is of the same material as the head, there is even less of an expansion difference between the two, making for a much better seal.
After all, the difference in expansion between the cylinder and the head is IMHO the mean reason for the aformentioned head-cylinder sealing problems...
So, I really do think its a cylinder problem. The heads are fine for most applications.
Regards,
Walter

Sven-Olof Brorsson · Post by **Sven-Olof Brorsson** » Mon Sep 01, 2003 6:25 am

Back to the sealing issue.......Let's look at things from a diffrent perspective. Why not go for a stock engine used in an enviorment of dirt (mud, sand...whatever) and a mix of water and oil builds up a cake insulating dirt on the cylinder covering all the fins. It's not a high performance car, only a daily mule lacking maintenance. What are the effects? They have a gasket, the same pattern for the studs and the materials used are the same, but do they have a problem with cylinder sealing? Only things that differs between the 94 and 103 is the lack of material....in the head.....
So back to the high performance side of things. What is lifting the heads and causing the leak? I would say high cylinderpressure. All of the Swedish car presented have high cylinder pressure and seem to work. So with the bad gas in USA would a car equipped with 103 seal better if compression is lowered enough as that is the reason for lifting heads?

Again, I'm only refering to my own experiences and lack knowledge of the enviorment and effects of other countrys enviorments and other circumstences. Some of the thinking could apply while some may not.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Mon Sep 01, 2003 7:39 am

Plain and simple- 103 cast iron pigs are JUNK!

I got tired of trying to make them work, so we just did research on better, smaller engines....Then Shad came along with the Nickies..

Having bragging rights to a huge engine that will not last more than 20,000 miles (If you are lucky) does sno good if the heads won't stay on it....

I push the TIV conversion for a more reliable, largere FACTORY engine that needs LESS modifications to make it's power. Adding 103s absolutely destroys that whole idea.

There are simply too many problems with the entire scenario with 103s to even think about solving them with anything less than a set of Nickies!