Heat Shields, do I have them all ?

I spent the weekend installing the shields between my engine tins and the CMC framework. I still have a few areas I am not sure about as I really am not that familiar with a Type 1 VW engine.

In front of my fan housing is the front engine plate and then a 2" or so gap between it and the fiberglass firewall of the body. Should the rubber "splash guard" in the CMC instructions seal this off or should it be left open for cool air to enter the upper engine compartment?

Also below the engine I have a pair of J tubes to a header instead of heater boxes. Since there are no heater boxes there are no bottom shrouds bolted between the oil sump and the boxes. I can clearly see the cooling fins and pushrod tubes. Will I get enough cooling this way or do I need the tins to keep the flowing air closer to these surfaces?

The fan shroud, upper cylinder covers, pully tins and breastplate are all there along with the stuff I added to seal the real of the compartment.

I am running a stock 1600cc dual port engine.

Thanks,
Tony Miller

Tony: Here we go...

"In front of my fan housing is the front engine plate and then a 2" or so gap between it and the fiberglass firewall of the body. Should the rubber "splash guard" in the CMC instructions seal this off or should it be left open for cool air to enter the upper engine compartment?"

Answer: The splash guard should seal this off effectively, however, don't bother with the thin material the CMC manual recommends - go to Home Depot and get a piece of 3/8 - 1/2" thick, shop floor rubber pad material (available off the roll in the carpet department) and use that instead. Make it big enough to fit the entire firewall area and drape down enough to be trimmed along the bottom of the flywheel side engine tin (paper templates work very well here). There are bulbous areas on that tin on either side of the engine in which you may drill holes to accept those plastic mushroom gizmos that are used for holding sound deadening material onto the underside of American car hoods (NAPA store). Push the mushrooms through the rubber material and then into the engine tin holes to hold it fast (or you can bolt it). The rest of the firewall mat can be attached with either 3M-90 upholstery adhesive or contact cement (which holds like crazy but may not let you re-position more than once...be careful!) AND put a couple more of those mushroom fasteners in nearer to the top of the firewall.

"Also below the engine I have a pair of J tubes to a header instead of heater boxes. Since there are no heater boxes there are no bottom shrouds bolted between the oil sump and the boxes. I can clearly see the cooling fins and pushrod tubes. Will I get enough cooling this way or do I need the tins to keep the flowing air closer to these surfaces?"

Answer: Yes, it'll work just fine. The fan is blowing DOWN and then out the bottom, which now has no obstruction to getting the hot air OUT!
BTW: If you don't have the CMC engine shields, you can either make up some paper templates to seal off the engine compartment from the bottom (it takes two to seal well) or I can send you a pair of paper templates to transfer onto HVAC sheet metal to seal the compartment up - your call...all I ask is shipping costs.

"The fan shroud, upper cylinder covers, pully tins and breastplate are all there along with the stuff I added to seal the real of the compartment."

Answer: Good! Keep it that way! You should also be running the thermostat (left side between the pushrod tubes) and the little air vanes within the fan shroud. Make sure everything is free (no binding) and works smoothly and easily.

"I am running a stock 1600cc dual port engine"

"Solid like a rock" - enjoy your toy!

Gordon

Gordon,
The rubber shield os easy enough. I have some pretty heavy rubber shop floor matting here already on a roll from the auto perts store.
I was going to do as you suggested and cover the entire firewall and make the botom fit that tin between the fan shroud and the firewall.

Underneath though there is no thermostat or linkage to the baffle/deflectors. Looks like it is open to blow through all the time. Will this be a problem? Not looking forward to stripping that all down and removing the fan shroud to fit new parts inside.

Tony

Well, on the thermostat and air vanes thing, I was always told that "the German designers put them in there for a reason, so don't peck with 'em". Jake Raby, with all his cooling studies, found just about the same thing - the vanes deflect the air precisely where it's needed for the best cooling for each cylinder (that was, I believe, on either a 36hp shroud, or the 1971 or later bigger doghouse version).

Having typed that, I have never run an engine (counting over 15 VW's I've built, so far) without the vanes and thermostat, so I have no reference for NOT running them. I know you can get the fan shroud off with the engine still in the car, IF IT'S IN A VW BEETLE SEDAN. I'm not so sure about removing it from a Speedster (anyone help here?) but I think it can be done if the alternator/fan is pulled first. If you CAN remove it in the car, it's pretty simple to install the air vanes and actuator rod in the shroud, and then the thermostat over on the Drivers side. Having the bottom of the engine open is OK, though.

Sounds like you've got the rest of it knocked. If the air vane thing is too daunting right now, spend $50 on one of those dip-stick thermometers from mainelycustombydesign.com and watch it. Depending on where you live, the weather and how you drive, you may be OK, who knows?

Gordon
The "Temporary Bachelor Speedstah Guy" from Rhode Island

Gordon,
I don't have enough experience to know their function for sure but did get an e-mail from another member here about them. They suggested their purpose was more a cold weather thing to restrict cooling air to the cylinders and therefore allow quicker heating through the heater boxes, etc... so the cockpit would heat faster in winter months.

I would think without the vanes in the shroud the cooling air would continuously blow downward onto the fins. With the vanes and thermo they would either shut or partially shut and then rerstrict cooling somewhat. Almost like leaving the thermostst out of a water cooled engine to reduce the water flow restriction so it did not overheat but at the expense of reducing cold weather performance.

Anyone else here with thoughts on this?

Thanks,
Tony

It's probably best to have them but I never installed mine and have been on the road for about 12 years in sometimes hot temperatures and with no heating problems (lucky?). Have a 1600 with dual Dell's, center-mount shroud, 009 distributor, comp headers, stinger, external oil cooler (mounted in the wrong place, need to change). Mostly requires a brief warmup in cold weather until it smoothes out and then I'm off and running.

I'm gonna save a lot of typing here and simply state that both you and your friend are dead wrong (and I don't come across this strongly very often). Those vanes direct air to where it is most needed on the heads BOTH when cold and hot. Also, you have to make a distinction between OIL temperature and HEAD temperature (which Jake Raby is always emphasizing). There's a BIG difference

Go to either or both of the Gene Berg or Jake Raby websites and see what they've found out about how the VW engine cools itself, what cools better and what doesn't. They BOTH have made the same discoveries over the years; among others, that the air vanes and thermostat are imperative to better cooling in the VW fan shroud - remove them and it simply won't cool the heads as well. BTW: this is something that the VW/Porsche racing crowd have known for years.

Also, removing the thermostat from a water cooled engine can often make it run too cool, which can often make it run too rich and cause the air/fuel mix to puddle up in the (cooler than normal) intake manifolds and cause all sorts of erratic performance.

On some water cooled engines (big-block Chevys with those BIG water pumps come to mind), removing the thermostat can actually make it run hotter because the fluid runs through the engine much too fast and doesn't cool adequately - it relys on the thermostat restriction for proper fluid flow and cooler operation.

Bruce: Do you have a dip-stick thermometer? How hot does your engine actually get?

gn

I guess I better get the wrenches back out of the toolbox again......

Now where do I get those vanes and thermo from ?

Thanks,
Tony

You might try getting an entire fan shroud (preferably in good shape) from a salvage yard (although more and more of them seem to be closing weekly). Please try to get REAL GERMAN tins - they work MUCH better than any of the imports. That's why the salvage yard stuff is usually a better deal. Take everything apart, clean it up and make sure nothing's bent and that it all works smoothly and easily.

For the thermostat on my last build, I ponied up for a new one from Mid-America (used to be Rocky Mountain Motorworks) just to make sure the thing would work right. At the same time, I also got all new air vane keeper springs to hold it all together. The whole mess (including the salvage yard fan housing and new fan) was under $50.

Gordon
One of the "Speedstah Guys" from Rhode Island

After rereading, maybe I misunderstood what you meant by "vanes". If you mean the tin that catches the air coming out of the bottom of the fan shroud and sends it over the cylinders then I stand corrected - I have them. I thought you were referring to something else. My thermostat is inoperable (absent) though.

Bruce,
By "vanes" Gordon and I mean the movable flaps inside the fan shrould and actuated by the thermostat. They open and close (and it seems direct the air path as well) out the bottom of the shroud and into the tins you are thinking of. I have those tins and some smaller deflectors under the cylinders but not the thermostat, linkage or interior vanes and springs.

Tony

You can get the shroud off with the engine in the car. You'll have to remove the deck-lid, and the throttle cable, and hold your tounge just right, but it is possible.

I added the thermostat and flaps to a retro shroud. Very involved PITA job. My car warms up during short drives and stays cool during high speed runs.

I replaced the aftermarket head tin with old German tin and the gap between the shroud and head covers was eliminated. Also the German tin had a deflector in front of the spark plug holes mising in the reproduction crap.