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I am trying to determine how many spacers should be installed when attaching the fan to the generator. On the fan side of the shroud where the air is drawn in there is a gap between the fan and the shroud. Is there a spec for the distance from the shroud to the fan? I have found information stating some spacers may be needed to keep the fan from rubbing, but I have not been able to locate any information regarding the gap between the fan and the shroud. Is it critical for cooling?

Thanks,
Mitchell

Concerning the spacer shims, I think the main thing is that there should be enough gap so that the fan does not act like a saw and cut into the fan shroud.
This link should help:
http://vw-resource.com/fan.html#gap

The only way that the "gap" could be wide enough to have any adverse effect would be if a "singleport" fan were used in a "dualport" (doghouse) shroud...but even then the cooling would be superior to that of a singleport shroud.
The inside width measurement of a dualport fan is approximately 35mm; singleport fans are ~6mm narrower. The shrouds are wide enough to provide about 2mm of clearance on either side of the fan, so there's some tolerance for lateral runout - but a DP fan will not fit inside an unaltered SP shroud.

Thanks for the information. I just would like to make sure the engine has all of the cooling that it should. The summer is coming and I live South of Houston, TX. The engine does run a little hot, at least according to the dip stick method. That is the dip stick is to hot to touch comfortably. The head temp runs at 350 as long as I keep the speed at 60 mph or less. I am in the process of installing an oil temperature unit in order to determine how hot the engine is running. The engine is in a 1970 Beetle convertible. It is a 1600 cc with dual port heads and 7.1 compression ratio. All of the seals are in place and all of the tin is in place. Just looking for any ways to keep it cool. Next will be an oil sump as I am using a 30 mm oil pump.

Thanks,
Mitchell

What engine lid do you have? The two-louver was marginal for the stock `70 1600SP, with a DP you really need a 4-louver in your part of the world.

Marc thanks for the reply. The deck lid has four vents. I purchased the car from the original owner about 18 years ago and the deck lid was on it then. I always thought it was the original deck lid, but from reading other posts I have learned this car should have had a 2 vent deck lid. Apparently it was changed.

I have completed installing the oil temperature gauge. After I drive it and check the oil temperature I will post an update.

Thanks,
Mitchell

And Mitchell,

Just to confirm, does the 1600 dual port engine have the doghouse cooler/shroud, or is the the original 1970 B series 1600sp engine with the old style in-shroud oil cooler - just converted to dual port with the original fan shroud?

If it does have the old style in-shroud oil cooler, that would be part of the reason it's running a little hot. The old style cooling was really at the limit with the 57hp 1600sp engine, and definitely not sufficient for the 60hp 1600 dual port engine.

Just for info, the old style 1300/1500/1600sp fan blows about 22cf/sec at about 4000 engine rpm (7000 fan rpm) where the wider doghouse fan blows 25cf/sec, and of course the doghouse has a completely separate air path for the oil cooler, so all four cylinders/heads get cool air, and more of it, for their cooling.

The Convertibles had a 4 louver lid..... just like all the rest, they deleted the verticals above the deck lid, so they had to account for that. The Deck lid you have is probably the correct, original lid.

Thanks for the replies. Rob I did change to the doghouse cooler for the dual ports with the larger fan. I just recently removed the fan and cleaned it to make sure the engine was getting all of the air it should. That was what prompted the original post as there was a small gap between the fan and the shroud. I did not replace the thermostat and deflectors as I had been informed they were not needed in this area. Also thanks for the info regarding the volume of air moved.

Scott thanks for clearing up the point regarding the vents. I have read several posts and articles with several different conclusions regarding the vents. I had always thought this was the original deck lid because of what the PO told me when I purchased the car.

Thanks,
Mitchell

At model-year changeover time VW often used up parts from the outgoing year before they started putting on the "correct" ones; although a 4-row lid is what belongs on a `70 convertible, it would not surprise me in the least to find one with the 2-row which is normal for `68/`69 convertibles and `70 Sedan. I've also seen cars which were damaged in accidents while "young" and repaired at dealer body shops using last year's parts...this is why I asked.

Not that it makes any difference to your situation, but just to satisfy my curiosity - is the slot-count in your lid 7-7-7-7 or 7-6-6-7? Does it have a stamped-steel "raincatcher" panel inside? Around here those're desirable, but you're probably better off without it.

It's been proven that the thermostat flaps actually help the cylinder heads run slightly cooler (being the last stage of air direction). Even on race engines with no thermostat I always install the flaps, brazed in the open position. A properly-operating thermostat can do no harm (the OEM bellows-style which fails open, anyway) and reduces engine wear by hastening warmup. It's unfortunate that you've removed these parts, but now your car is like most on the road today - it doesn't make a huge difference in head temps so I wouldn't bother to put the flaps back in just yet, but don't throw them out!

Mitchell wrote:...I did change to the doghouse cooler for the dual ports with the larger fan....

Also the two pieces of oil cooler exhaust ductwork and the firewall tin? Are all of the seals present, including the strip over the top of the cooler? If any of the 4 rubber seals on the ductwork are missing the airgaps can be sealed with RTV; a strip of carpet pad makes a good replacement for the one glued around the cooler.

How about the "Hoover Bit"?
(bottom of page): http://www.oldvolkshome.com/oilcool.htm

A large-passage case with a doghouse cooler or the `70 large-passage SP cooler should have the 021 117 151A seals (usually red/orange in color). The green (sometimes gray) 111 198 029 "conversion" seals may fit without leaking but they will restrict the oil flow.

HI Mitchell,

I agree with Marc's words of wisdom above.

I just posted the following stuff on another thread but it's relevant here too, as you said you had removed the thermostat and cooling flaps.

Those movable cooling flaps have TWO functions.

1. They work with the thermostat to provide a fast and even warm-up of the engine. The rate of warmup is also timed to work with the rate that the choke winds itself off. The fast warmup also helps prevent icing under the carb as it ensures that the exhaust gases in the heat riser get up to normal running temps faster (icing does not occur in snowy conditions when the air is already dry - it happens most in humid conditions with temps above freezing).

2. But if you have no thermostat (you should - even if you live in a hot climate), they still have a second function - when open, the outer movable flap touches the inner edge of the head finning, resulting in a separate air path inside the shroud for the heads and the cylinders. Since the air is driven outwards from the fan around the edges of the shroud a little more than through the middle of the shroud, those flaps result in a larger proportion of air going to the heads, and a smaller proportion going to the cylinder finning. Since the heads run hotter than the cylinders, this balances the cooling better. Without those movable flaps (held open if no thermostat is fitted), the cylinders get slightly overcooled and the heads get slightly undercooled.

A lot of folks forget that if they alter the original VW design, they become, in effect, the "engineer". Most times you can get away with it, but I prefer to trust the VW engineers myself - they were building the car to a price, so they did not do anything they did not have too, yet they spent over million US dollars in 1969-70 just redesigning the cooling shroud for the doghouse fan and shroud, so they obviously thought every piece was important. If you remove stuff, you alter their carefully thought out design.

So I'm a fan of keeping things as stock as possible, and the result is that my 1970 1500sp engine (I bought the car brand new 43 years ago) has over 400,000km on it with only one rebuild (now a 1600sp, but with everything else stock).

Marc, the hood is a 7-7-7-7. There was no rain catcher when I purchased the car. I do have the two pieces of tin and the firewall tin installed. I made two seals for the two pieces for the oil cooler exhaust. I will have to do a little research to determine what I am missing. I also do not have the one that goes across the oil cooler. I am fairly certain I used the correct seals when I assembled the engine. I do have the hoover bit, but from what I have seen in pictures a portion of mine is missing so I need to fabricate the missing piece.
Rob, I also agree with Marc about the flaps. I have been doing quite a bit of reading and it does make sense, especially when you and Marc point it out so that it is very easy to understand. I really like your site, very helpful.
I did drive it after installing the oil temperature unit. Driving 60 mph the head temp was 350 C and the oil temp was about 215 C. This was after 15 minutes of driving. The oil pressure was 35psi at 60 mph, but the light flickered at idle. After allowing the engine to cool off the oil pressure came up and the light went off.
I plan to install the flaps when I remove the cooler to correct the rest of the issues. Unfortunately for me I just sold a second set that I could have installed on the motor I am building for my 1973 Karmann Ghia convertible. Hopefully I addressed everything.
Thanks for all of the information,
Mitchell

IIRC the 7-7-7-7 lids were unique to `70 and `71 convertibles, newer lids are 7-6-6-7.
Your oil temp seems a bit high to me, but gauges vary. So far as you know are the plungers and springs all factory-stock? If you have a 9.5mm fanbelt, replace it with the 11.3x912. No chromed pulleys, right?

Thanks for the information. I checked the temperature gauge, installed in the engine, against a calibrated temperature probe and at 180 C the gauge was fairly accurate. I know the plunger and spring in the oil relief were changed to the stronger spring. I believe the oil pressure control is stock. The belt is the 9.5X905. I will change it. I also need to verify the oil cooler seals. After I thought about it I do not know if I check the seals on this engine. I acquired the engine when I purchased a VW 71 Super. The case is an AR case, if you remember I asked about this case a few weeks ago as someone had drilled a hole to install a fuel pump. I am using it to as a temporary replacement for the engine I had in my car. I had purchased what I thought was an oil pump for a dished cam. Turns out it was not. Even though the supplier measured it, I ended up with the wrong pump. After driving for a while the pump slipped out of the slot in the cam and the number one and number three bearing locked up. As we had several shows coming up I installed this engine so we could attend.

Yes the pulley is a stock VW pulley. At one time I had an aluminum pulley on it, but I thought it might be causing the problem. The aluminum pulley looks to be smaller than the stock pulley.

Thanks,
Mitchell

I hate the "official" nomenclature for the oil pressure control & relief valves since it's not really descriptive of their functions, so I just refer to them as the "pump-end" and "flywheel-end" to be sure I'm understood. The flywheel-end one has one function, to relieve any pressure above ~65psi to keep from blowing coolers - ordinarily there's no need to change anything there.
The pump-end one pushes down under high pressure (interpreted as cold oil) to uncover a passage that leads directly to the bearings. The passage up to the cooler (and oil pressure sender) is always open, but when the bypass is open it offers less resistance so most of the oil goes that way, promoting faster warmup. Stiffening this spring, or shimming it, will make the bypass close at a higher pressure so warmup is delayed. Pressure will therefore be a bit higher over a short trip, but once you've driven long enough to get to full operating temperature there is zero effect (other than one more shiny piece in your engine and a few more in the seller's pocket).