Thermostat friendly 1 3/4" merged header

[Jeff68]

I have to go from a 1 5/8 merged header to the next size up which is a 1 3/4.  Right now I have a 1 5/8" Berg header that clears the thermostat. The 1 3/4 Berg header doesn't clear the thermostat as it's designed mostly for racing (the catalog says). I looked at the A-1 low down, JPM / CSP Wasp and they don't clear the thermostat either. It seems once you go larger than a 1 5/8 the headers available are not made to clear the thermostat and I'd really like to run the engine with the thermostat.  The only option I can see is that you can get a 1 3/4 A-1 header and the A-1 1 3/4 heater boxes and I'm thinking that this would clear the thermostat. I live in Florida so I don't really need heat in my car so I'd rather not use heater boxes. I also prefer the "straight out the back" collector configuration (non sidewinder). I do want to run as much of the VW factory cooling tin and thermostat as possible.

So, does anyone know of a 1 3/4" header that clears the thermostat? I guess I could buy a header and try to modify it but I wanted to check to see if anyone knows of an off the shelf header that will fit.

Thanks guys.....

[vwhelmot]

Thermostat isn't really needed. Just make sure the cooling flaps are there and wired open so to direct the air flow correctly over the cylinders. My motor never had the thermostat fitted and I never had problems.

[neil68]

I looked at the A-1 low down, JPM / CSP Wasp and they don't clear the thermostat either.

I do want to run as much of the VW factory cooling tin and thermostat as possible.

So, does anyone know of a 1 3/4" header that clears the thermostat? I guess I could buy a header and try to modify it but I wanted to check to see if anyone knows of an off the shelf header that will fit.

Thanks guys.....

I run a JPM-CSP Wasp Stage 2 and it clears the stock thermostat.

I also run all the OEM engine tin, although I did have to trim the lower sled tin slightly to clear the J-pipes (alternatively the edge of the sled tins could be bent upward and closed in with industrial tin).

[karl h]

i have an old Scat 1 3/4 header that clears the thermostat with some modifications to the bracket. i would never run an engine on the street without all the stock tin and the thermostat (just imho)

[Jeff68]

Thanks guys.....I didn't know that the Wasp header cleared the thermostat, thanks Neil.
Jeff

[javabug]

Check with Dave Greiner at Proformance. He's got some headers listed on the samba that look a lot like the old Phoenix/Berg merged. I don't know if he's got something larger than 1-5/8", but it could be worth a call.

[Jeff68]

Thanks Java, when I'm ready I will. I also may check with Joel Mohr about the step headers that he makes to see if they clear the thermostat.

[Jeff68]

Well, for anyone interested here's what I found with regard to a 1 3/4 header that accommodates the use of the thermostat and sled tins / industrial tins. The only header 1 3/4 header that allows the use of the thermostat and sled / industrial tins in the Wasp header from JPM. It seems as soon as you go larger than 1 5/8 the headers are not made to clear the thermostat and sled / industrial tins. I also wanted to use a Berg traction bar. Other headers clear the traction bar but the Wasp doesn't, I'd have to make my own (no big deal).

Some very knowledgeable and experienced VW people say that you don't need the thermostat or sled tins and that they have run without them and haven't had any cooling / overheating problems. What do those who are running a 1 3/4 header on the street say? I'd like to hear from anyone who is running a 1 3/4 header without a thermostat and lower tins (sled tins). What is your experience? I know the thermostat just ensures that the engine warms up uniformly and maintains correct operating temperatures and probably doesn't aid in cooling.

I know I'm probably overthinking this but I really do drive my car on the street, up some steep hills occasionally (Sunshine skyway bridge in St. Petersburg Florida), and on 150 mile highway trips at 70 mph. It gets hot here in Florida so that's why I think about the cooling aspect.

Just gotta make up my mind and go for it.........

 

[Jim Ratto]

Jeff,
I've run a 1-3/4" header, off and on (mostly on) since 1991. Admittedly, some of the engines that have been under my decklid were poorly thought out as far as cooling and ability to drive anytime, anywhere. I'm referring to the engines that had Super Flow heads and aftermarket fan-shroud, cut up cylinder cover and rear cooling tin (by apron). These engines had serious heating issues, but obviously not from the header size/routing or lack of thermostat/directional vanes.
The following is fact:
Since 2006 I have run a 1-3/4" header on my 94 x 78mm with 044 casting heads, a factory VW shroud and cylinder covers, and at least 9.5:1. In the months between March and November, here in Southern CA, I run a stock size lower pulley and stock alternator pulley. I have a stock doghouse cooler (T1) and a Setrab dual-fan cooler (fans fed by fresh air scoop near r torsion tube). I cannot run thermostat. I have over 50K mi on my heads and p/c since 2006. The cylinders have been re-honed once, new rings to go with. As far as obvious signs of heating issues (tight valves, loose head nuts, wasted guides, milky-glazed plugs, death-ash on exhaust valves, espresso looking film on underside of piston or in rocker chambers, peppering on plugs or piston tops, loss of ring tension, etc), I've yet to experience any of it. I believe my car runs cool because I spent a lot of time tuning it to run cool and run without mixture or timing induced hiccups/holes etc that almost always manifest in heating problems.

The following is my opinion:
Is the thermostat "needed?" On a car running a fresh air style heating system in a cold climate, driven by a person that wants good heating immediately..... YES. Does it affect the wear and tear on the engine, driven by someone with NO mechanical sympathy for the car? YES. Has my car suffered any because of it missing it? NO. 
In my opinion, the thermostat system (the one that bolts to the case, under cyl 1 & 2) was introduced (same time fresh air heating was) because the earlier thermostat was reducing air volume through fan, by restriction (lessening the amount of heating air sent through heating). If you read road test reviews of old 36-40 HP VW's everybody bitched about the heater in these cars, how they were like a mouse's breath. The early thermostat was designed to keep engines from running too cool on long downhill grades, in alpine climates.
The newer thermostat works differently, not restricting air to heating system, in fact, when it has the vanes "closed" it's forcing MORE air through heating. I believe this was done to improve passenger comfort, with less emphasis on engine wear. Remember, the stock motor had cast pistons. We typically run forged... which require wider skirt to wall clearances. How does the thermostat account for that? We run cams that lift in excess of 0.500", against valve springs that would tie stock pushrods in a knot. That DOES increase oil temperature over stock valvetrain. (how much influence the stock thermostat has over oil temp I am not sure of).
In any case, there are other things we do to these engines, cam, mixture, rpm, type of heads, ignition curve, etc, that I think either balance out or negate what the thermostat does or can do. I would opt to run a correctly sized header for your engine, anyday, over losing sleep about the stock thermostat.

Have fun

Jim

[Jim Ratto]

One more thing to remember

The 356 and 912 never had any kind of air restricting flaps or fan ring.

[Frank LUX]

Jeff,
I've run a 1-3/4" header, off and on (mostly on) since 1991. Admittedly, some of the engines that have been under my decklid were poorly thought out as far as cooling and ability to drive anytime, anywhere. I'm referring to the engines that had Super Flow heads and aftermarket fan-shroud, cut up cylinder cover and rear cooling tin (by apron). These engines had serious heating issues, but obviously not from the header size/routing or lack of thermostat/directional vanes.
The following is fact:
Since 2006 I have run a 1-3/4" header on my 94 x 78mm with 044 casting heads, a factory VW shroud and cylinder covers, and at least 9.5:1. In the months between March and November, here in Southern CA, I run a stock size lower pulley and stock alternator pulley. I have a stock doghouse cooler (T1) and a Setrab dual-fan cooler (fans fed by fresh air scoop near r torsion tube). I cannot run thermostat. I have over 50K mi on my heads and p/c since 2006. The cylinders have been re-honed once, new rings to go with. As far as obvious signs of heating issues (tight valves, loose head nuts, wasted guides, milky-glazed plugs, death-ash on exhaust valves, espresso looking film on underside of piston or in rocker chambers, peppering on plugs or piston tops, loss of ring tension, etc), I've yet to experience any of it. I believe my car runs cool because I spent a lot of time tuning it to run cool and run without mixture or timing induced hiccups/holes etc that almost always manifest in heating problems.

The following is my opinion:
Is the thermostat "needed?" On a car running a fresh air style heating system in a cold climate, driven by a person that wants good heating immediately..... YES. Does it affect the wear and tear on the engine, driven by someone with NO mechanical sympathy for the car? YES. Has my car suffered any because of it missing it? NO. 
In my opinion, the thermostat system (the one that bolts to the case, under cyl 1 & 2) was introduced (same time fresh air heating was) because the earlier thermostat was reducing air volume through fan, by restriction (lessening the amount of heating air sent through heating). If you read road test reviews of old 36-40 HP VW's everybody bitched about the heater in these cars, how they were like a mouse's breath. The early thermostat was designed to keep engines from running too cool on long downhill grades, in alpine climates.
The newer thermostat works differently, not restricting air to heating system, in fact, when it has the vanes "closed" it's forcing MORE air through heating. I believe this was done to improve passenger comfort, with less emphasis on engine wear. Remember, the stock motor had cast pistons. We typically run forged... which require wider skirt to wall clearances. How does the thermostat account for that? We run cams that lift in excess of 0.500", against valve springs that would tie stock pushrods in a knot. That DOES increase oil temperature over stock valvetrain. (how much influence the stock thermostat has over oil temp I am not sure of).
In any case, there are other things we do to these engines, cam, mixture, rpm, type of heads, ignition curve, etc, that I think either balance out or negate what the thermostat does or can do. I would opt to run a correctly sized header for your engine, anyday, over losing sleep about the stock thermostat.

Have fun

Jim

Amen Brother..!!! Perfect!!!!

Frank

[Jeff68]

Great reply Jim! Thanks for taking the time to answer my question and give your personal experience. I didn't know that the 356 or 912 didn't have a thermostat either, that's good to know.

After some thought I'm really not that concerned about not running a thermostat. I did want to run the sled tins to keep air flow around the heads but I'm not sure how critical they are or that I'm convinced that they are needed either.

I just have to make a choice, see how it works and make adjustments as needed.

Thanks

[Joel Mohr]

Jim gets my vote too...

[Zach Gomulka]

Porsche 356/912 absolutely did use a thermostat.
http://forum.porsche356registry.org/viewtopic.php?f=1&t=24702
http://www.sierramadrecollection.com/Thermostat-Connecting-Rod-All-356-s-912-p18937.html

[Martin S.]

The oil/case cooling and head cooling are two different systems independent of each other. We found that having an efficient chamber where everything that goes in gets burnt makes all the difference in head overheating. The thermostat does seem to only affect heater box flow and interior comfort. There's a also lot more interior heat flow with a dual port shroud wide fan system and a single port narrow fan.

[Jim Ratto]

Porsche 356/912 absolutely did use a thermostat.
http://forum.porsche356registry.org/viewtopic.php?f=1&t=24702
http://www.sierramadrecollection.com/Thermostat-Connecting-Rod-All-356-s-912-p18937.html

This routed warm air to carburetors

[Zach Gomulka]

Porsche 356/912 absolutely did use a thermostat.
http://forum.porsche356registry.org/viewtopic.php?f=1&t=24702
http://www.sierramadrecollection.com/Thermostat-Connecting-Rod-All-356-s-912-p18937.html

This routed warm air to carburetors

Correct. I wonder how effective it is compared to the VW flap system?

[Jeff68]

As far as the thermostat - I thought I had read that the thermostat helped ensure the engine got to operating temperature quicker which helped reduce engine wear.  Where I live / drive my car the outside temperature is pretty consistent year round except in the summer when it gets very hot and humid....I usually only drive it when it cools off in the morning or evening.

Thanks guys

[Joel Mohr]

I agree. In my opinion, the flaps closing at cold temps helps the "warm up", but after they open, they just obstruct air flow. That was the theory back in the day, and why every one I knew with HP builds would take them out. If you don't live in a sub 30* climate, they were useless...The BIGGEST change I've seen in the last 35 years, has been better understanding of chamber design and compression ratio. I build big motors all the time with Hemi cut chambers and 10 to 1 with no heating issues..and I live in the desert...Having a dyno has really opened my eyes to the possibilities, and studying what the auto industry evolution has done to the efficiency of the internal combustion engine just in the last 20 years is astounding....

[Martin S.]

.. It's all about the chamber.. 

[Jeff68]

Thanks for the information Joel.

[javabug]

I run the thermostat and flaps on my car with an aftermarket 36 hp shroud. 90.5x82, 9.5:1, 86b. My reasoning is that this time of year if the roads haven't been salted yet but it's 30ºF and I want to take my car for a ride, I won't need to drive 50 miles to get it up to temp. I also ran it for a few years without the thermostat and flaps. The only real difference I have seen? The head temp gauge has read more consistently with the flaps installed. Temp range has stayed about the same.

Not to reiterate, because Jim said it the best, but your engine will be fine without the thermostat stuff, especially in your climate.

[Joel Mohr]

Perfect! Exactly my point....My street car was 11.2 to 1 Web special grind .640 x 310* and I drove it every day...Hemi cut and detailed by Clyde Berg. No heating issues... I have a motor in one of my play cars that will be going to 12 to 1 on 91 octane. I'll post the results...

[Martin S.]

What gas? With 9.5:1 I can lug our 1776 without ping even with regular cheapo gas. No overheating either.

[Joel Mohr]

A lot of detonation occurs long before it's audible...and depending on your cam, there may be low cylinder pressure in the range you are "lugging" it...

[Martin S.]

The nice thing about the high CR is that the timing does not need to be advanced as much. I was able to retard it enough not to ping, yet it still makes power. The bottom end (Berg 69 CW crank, etc.) is going on 16 years now being used every year since 1999 and didn't need opening up when we rebuilt with high CR. Tight deck height/flame port worked wonders for that thing!
The other aspect to that car working well is that it still has the 4.375 RP trans. Wife beats on it and short shifts plenty but still can't kill it.