Author Topic: Deleting throttle body heater plate. (Read 87682 times)

D. Clay · « **on:** August 31, 2007, 04:29:41 PM »

Upper water outlet capped off at head.

Lower water line capped on plastic pipe on the side of the block.

Throttle body on intake with shortened studs.

PCV line from valve cover to throttle body.

Air inlet to idle control valve.

Lines at ICV valve.

To close off the water circuit, I used rubber heater hose caps from the "Help" section at the auto parts store. The line from the valve cover to the throttle body runs direct. Half inch heavy duty heater hose runs from the intake boot to the bottom of the ICV with a 90 degree plastic connector on both ends. The section from the ICV to the intake is under vacuum and needs to be stiff. With a third 90 degree connector, the hose is supported. The mount bracket holding the ICV valve to the intake was bent slightly at the intake to move the ICV inlet toward the firewall. The inlet is right over the hose to the heater originally. Moving it toward the firewall gives more that enough clearance. The maze of siamese hoses under the intake is gone. No problems with over heating due to the water outlets in the head being capped. I heard from another M42 owner that has a track car with no heater. He has a hose looping from the throttle body heater outlet to the heater outlet with no overheating problems.

BrandC · « **Reply #1 on:** August 31, 2007, 05:02:34 PM »

Wait, so it's safe to completely remove the hose connecting the "coolant pipe" to the cylinder head outlet? I just looped mine and now I think I'm going to completely remove the hose like you!

I'm not sure what you are trying to explain in the bottom paragraph about the ICV connections and such. Could you show us some more pictures to explain?

tjts1 · « **Reply #2 on:** August 31, 2007, 07:05:54 PM »

+1
I went to a lot of trouble tying to fit a lenght of hose between the 2 ports when I got rid of that mess of hoses. I was tempted to do the same thing but I think that port is important for removing hot coolant from the middle of the head. Thats the spot where the head typically cracks when its overheated. Please update after you have a few hundred miles on the setup. If this turns out to be safe I would be happy to do the same thing.

D. Clay · « **Reply #3 on:** August 31, 2007, 09:36:10 PM »

I thought of that also, but the there's no outlet between cylinders 1 and 2 and BMW doesn't put the TB heater on tropical models. They also make shorter TB studs for the tropical model (M6 X 28 vs. M6 X 40). http://www.realoem.com/bmw/showparts.do?model=AF91&mospid=47256&btnr=11_0953&hg=11&fg=40
I think it would be more critical on the exhaust side but there's no outlets there at all. Old small block Chevrolet's had a problem on the exhaust side where the two center cylinders had the exhaust ports next to each other. The solution was to add a bleeder for steam there and run the lines to the thermostat housing. It wasn't always successful.

tjts1 · « **Reply #4 on:** September 01, 2007, 01:29:57 AM »

Well they still put on the lower TB heater on the tropical mode. #11.
http://www.realoem.com/bmw/showparts.do?model=AF91&mospid=47256&btnr=11_0560&hg=11&fg=35
But I think even if the heater isn't used at all, you still need that hose to carry hot coolant away from the head in order to maintain an even temperature between all 4 cyls. Have you driven the car yet with this setup? I'm all for deleting the TB heater along with all the messed up hoses under the intake but I wouldn't want to be the first to experiment with completely plugging up the coolant ports.

gearheadE30 · « **Reply #5 on:** September 01, 2007, 08:03:16 AM »

+1 to tjts1

I am also planning to remove both heater plates from my car, and this seems significantly easier than trying to make other lines fit, if it is safe for the engine.

christophbmw · « **Reply #6 on:** September 01, 2007, 11:37:22 AM »

one question forthose of you you live in high humidity relatively cold places that have removed the TB heater: have you noticed any difference? im only asking because i have been thinking about it but im afraid of getting ice buildup in the winter. the M42 is such a great breathing motor so the humid air could easily cause buildup (very small amounts) inside the TB.

D. Clay · « **Reply #7 on:** September 01, 2007, 12:19:39 PM »

Anyone else plugged the opening the head?
Link to thread with pics of two cracked heads, both with cracks between exhaust valves and the water jacket.
http://www.m42club.com/forums/showthread.php?t=3427&highlight=head
Is this where the heads usually crack? I haven't driven the car yet as it's still going back together. I am also searching for references to this on the E30 sites.
I just noticed after reading the above thread that there are only very small holes in the head gasket by the exhaust valves. Anyone know the reason for this? The water jackets are almost completely covered.

cecotto · « **Reply #8 on:** September 01, 2007, 01:25:37 PM »

My view is that the pipe marked in green is a suction point, that is connected to the suction side of the waterpump. This pipe is responsible for pulling hot water through the heater core through the hose # 23. When the heater is set to cold no water flows through #23.

Also the throttle body heater loop is driven through this suction pipe, the throttle body heater draws its hot water through the connection marked in red. I'm pretty sure that this connections primary reason for being there is to supply the hot water for the throttle body heater. Not to supply extra cooling for the head at this location.

The water circuit is in my understanding like this:
The water gets drawn through the block. and flows internally through the oilpump housing to the thermostat, where it's either pumped through the head. And further down the block again. Unless the thermostat redirects the flow through the radiator. In this instance cooler water is added to the circuit, until the thermostat is cooled enough to close the radiator off.

In my view it makes no difference if the water is recirculated through the red outlet and the system of hoses and heat exchangers or through the block in it's usual path.

On my engine the hoses: 11+13+16+25+26+17+18+14+15 will all be deleted, and the red outlet pluged.

cecotto · « **Reply #9 on:** September 01, 2007, 01:33:24 PM »

Quote from: D. Clay;32896

I just noticed after reading the above thread that there are only very small holes in the head gasket by the exhaust valves. Anyone know the reason for this? The water jackets are almost completely covered.

Please read the above post and rethink your question. Then i'm sure you'll have the answer.. :-p

Well as the water starts it's jurney through the front of the head and needs to cool all four cylinders, the cooling system would actually be better off without the small holes. Notish that on the fourth cylinder theres a fully open path for the cooling water to entr the block, and flow towards the first cylinder and eventually reach the pump..... (If all the small holes were fully opened the fourth cylinder would see very little coolant flow)

The only reason for the small holes is to be able to bleed the system, if they were not there air pockets would be able to be trapped there.

Hope this makes sense.

tjts1 · « **Reply #10 on:** September 01, 2007, 01:41:46 PM »

Looking at the picture above, hose #4 connects through fitting 6 to water pipe circled in green. The other end of hose #4 goes to the bottom of the radiator on the left side. This smaller hose takes hot coolant from the water pipe to the radiator all the time and is not regulated by the thermostat. Its not big enough to cool the entire engine but it helps maintain a constant temperature across the length of the engine.

Put another way, the water pipe is an outlet. It is fed by the block, the small port on the side of the head between cyl 2 and 3, and by hose 22 coming from the heater. When the thermostat is fully closed, this water pipe functions as a small bypass to prevent pressure from building up in the head and block.

Quote from: cecotto;32899

The only reason for the small holes is to be able to bleed the system, if they were not there air pockets would be able to be trapped there.

So if we plug up the small port between cyl 2 and 3, air would also get trapped in the head and cause that area to overheat.

cecotto · « **Reply #11 on:** September 01, 2007, 02:17:08 PM »

Quote from: tjts1;32900

Looking at the picture above, hose #4 connects through fitting 6 to water pipe circled in green. The other end of hose #4 goes to the bottom of the radiator on the left side. This smaller hose takes hot coolant from the water pipe to the radiator all the time and is not regulated by the thermostat. Its not big enough to cool the entire engine but it helps maintain a constant temperature across the length of the engine.

Put another way, the water pipe is an outlet. It is fed by the block, the small port on the side of the head between cyl 2 and 3, and by hose 22 coming from the heater. When the thermostat is fully closed, this water pipe functions as a small bypass to prevent pressure from building up in the head and block.

So if we plug up the small port between cyl 2 and 3, air would also get trapped in the head and cause that area to overheat.

I think you're telling me i got the direction of flow wrong...

Well i dont think so, please have a look at the direction of flow arrows on the hoses #23 + #22, if water was to be flowing from the block out the green connector we would have a collision of water there.

BMW calls the hoses by these names also:
22 : Water hose outlet (Outlet from the heater core)
23 : Water hose inlet (Inlet to the heater core)

The hose #4 is the circuits connection to the expansion tank, and the system will draw from this resaouir when ever it needs to.

Also have a look at the pump propeller wheel which i added for refrence. The engine would have to be turnng backwards for the water to flow in your suggested direction :-P

tjts1 · « **Reply #12 on:** September 01, 2007, 02:35:24 PM »

EDIT:
Looking at it again, I think you are correct about the flow direction.

I still don't think that blocking off that port is a great idea. But if somebody is willing to try it and prove me wrong I'm willing to listen. I would love to plug up the port instead of the hose I have in there now if its proven safe.

D. Clay · « **Reply #13 on:** September 06, 2007, 09:46:43 PM »

Original post updated 9/6/2007.

bmwpower · « **Reply #14 on:** September 06, 2007, 10:38:37 PM »

I deleted the heater on my M20 TB a loooong time ago...no problems to date. Much easier to do on that engine though.

I don't like those "Help!" section caps. They scare me too much to use them in this application. They're not braided rubber and have a tendency to breakdown with the hot/cold cycles. Not sure what else you could use...maybe a short length of hose with a plug clamped on the end.