phenryiv1's 1989 325iC Project - SETA 2.7i Swap Complete and Running!

[phenryiv1]

I also picked up a replacement HVAC panel to replace my broken one.



On my way to NY for work I stopped by Guten Parts to pick up replacement (new) OE convertible lower body trim and some switch blanks. Somehow no pictures of those (or the trip to Guten) but hopefully they will finish off the look of the bottom of the body (where the white clips are on the driver's side in the pics).

[phenryiv1]

It has been a while but I did a thing (actually 2)!

Changed the oil (first time since the swap) and rotated the tires!





I did notice a bit of seeping oil from below the front of the head at the valve cover but nothing too bad. I tightened up the front VC nuts to see if that helps.





Also, the oil was very clean and the magnetic plug had very little on it despite nearly a year (but still probably no more than 3000 miles) since the last change, which occurred concurrently with the motor swap last spring. When pouring it into the waste container it was still clear enough to see through it.

[phenryiv1]

I almost forgot to post that I picked up another BMW. I snagged an E61 in January as a daily driver.

[phenryiv1]

Some progress of late.

So the car was starting to overheat in stop and go traffic so I was fearful of an air bubble in the cooling system. My worst-case-scenario brain was thinking something worse but there is no indication of any other issues so I started with the most simple possibility- the thermostatic control unit for the electric fan.

When I did the SETA 2.7i swap there was no mechanical fan so I used the same Hayden/Imperial controller as I did in the RallyX car. It is Part No. 226204.

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_adjustable-thermostatic-fan-control-imperial_3670006-p

Like before, I had installed it near the passenger side headlight, hooked it up to the fan (with reverse wiring since it was to be in "push" configuration) and wired the controller to the car. The wiring is ugly but it worked for what I needed it to do.



I wired the 12V+ to the firewall terminal, grounded the fan and controller to the same point on the chassis, and used a 12V+ constant for the "signal" lead (supposed to be switched 12V+ so that it is off when the car is off) but I wanted it to be able to run after shutdown in the event the engine was still hot after driving.

The temp probe goes in the radiator.

For a while it functioned as it was supposed to but after a while I determined that it was never kicking on.

I researched the Hayden/Imperial controller and the consistant feedback was that it died after several months of use. The relay woudl be fine but the controller woudl fail in either the temperature sensor lead or the potentiometer in the variable temperature control.

I swapped relays- no change.

Then I juiced up the "override" button (which I stupidly had never hooked up to a 12V+ switch in the cabin) and the fan worked. So we know it isn't the controller, the relay, or the fuses/wiring.

Next up I let the car get hot and it still never kicked on so on a whim I messed with the thermostat, dialing it back to the coldest set point...and it worked! I played with the dial for a bit and now it seems to kick on/off as it is supposed to.

Just to be safe I will be wiring up the override switch to the cabin but at least I have it working at least somewhat at this point. I will also add a heat shield to the controller since it is on the same side as the exhaust maifold. No harm in doing that.

Next up was to play with the DME a bit. When I bought the car I was told that it had some aftermarket chip in the DME but I never knew which one or whether the guy was telling the truth. The car ran, however, so I never thought much about it. The car seems to stumble just as I get on/off the throttle, particularly at low speeds. I was also getting an intermittent hard start (may be a function of a failing temp sensor but I have not investigated) so between those issues I figured that it might be DME related.

When I swapped in the SETA 2.7i, the car came with a DME that was tuned for the M50 injectors (17#?) and had a raised rev limit. I was lazy and never installed it but yesterday I finally plugged it in. I went for a short test drive with the old one still in place but after playing with it a bit I like the throttle response of the "new" DME over the old one.



Turns out that the old one was actually a 380 and though it is probably not original to the car (380s were used late in production but since the convertibles were bastard cars, who knows?) it did not look like the tabs had been opened so it was probably just a bone stock 380, which would explain why it had trouble accounting for the larger injectors.

[95maxrider]

Ebay chip to the rescue! IIRC the rev limit should be 7000.

[phenryiv1]

So unfortunately the cooling system woes resurfaced.

I am rarely in stopped traffic for more than a minute or so and I by the time I get to my house it is 4-5 minutes of 30-55 MPH driving from the interstate to my house so for the fan to NOT be on in the driveway/garage is not uncommon. Just this weekend I was wondering to myself if the fan controller was still working. Yesterday i determined that it was not.

I had been out driving around with my daughter, a mix of back roads and interstate. After 15 minutes of driving I sat in a drive through. As I got on the interstate I saw the temp gauge climb and the coolant light illuminated. I limped home (2 miles) and opened the hood and it was a mess. Dry coolant tank, coolant everywhere, no fan running. I let it cool off and refilled the coolant reservoir, then started it for about 10-15 seconds.

When I squeezed the top radiator hose I saw coolant spew from the hose that goes up to the throttle body (throttle body heater?). I have no idea what is going on. Cooling systems are not my forte.

The TB heater is attached to the TB by RTV (due to stripped screws, I assume) and it looks like when the system heated up and pressurized that was the weak point.

Obviously I need to remedy that (FaceBook R3v'ers suggest bypassing the TB heater function altogether) but it may be a good time to make an investment in a new fan controller and possibly to make the plunge toward aftermarket temperature gauges. It is also clear that I need to get the override switch wired up, as I could have at least had the fan in forced operation when the controller failed.

I am embarrassed to say that in my panic I failed ot think to turn on the heater so who knows if I would have thought to use the override. When I saw coolant on the hood I freaked out.

I actually have a bunch of other progress on the car that I need to post about but this is pushing those things to the wayside at the moment.

[phenryiv1]

Holding pen for cooling info (for me):

http://www.r3vlimited.com/board/showthread.php?p=2592222#post2592222

https://www.electronicspoint.com/threads/12v-automotive-cooling-fan-indicator-light.281952/

http://www.hotrodders.com/forum/fan-indicator-light-148416.html

[phenryiv1]

Mulling this over now:

My 2.7i swap came with the mechanical fan deleted so I went with an electric fan. I had it running off of a thermostatic controller (temp probe in radiator) with a relay. Unfortunately, the controllers have a reputation for failing, which is what happened to me. The circuit board had continuity issues and the board kept losing power but I never knew if it did or did not have power because hearing the fan run with the engine running was impossible.

So last week I realized that the controller had shit the bed…mostly because I saw the temps shoot into the red and the car pissed coolant from a blown coolant passage. Fortunately the head gasket did not go- the gasket at the TB heater failed first (thank God).

Now I am trying to build a new fan controller based on a switch in the A/C fan port in the body of the radiator. Plan is to use either one or two 5-pin relays. I can either use a 2-relay system that has an override switch in parallel with the thermostat switch on a single-relay setup OR I can run 2 totally separate parallel relays – one thermostatically controlled and one manually controlled. A single will be easier to wire up but a double relay system has the benefit of redundancy.

Obviously the 30/51 will be fed with a fused 12V+ signal and terminal 85 will be grounded. Terminal 87 will feed the fan when triggered. The assistance comes in two areas: The use of the 87a terminal and setting up “indicator” or “status” lights associated with 87 & 87a.

So the new setup will use an 80*C switch trigger that goes into the A/C port in the radiator. It will supply the trigger to the 86 terminal on the relay. I can also run a simple toggle switch in parallel to the terminal 86 or I can run the second relay. Which would you recommend- two relays with discrete triggers or dual triggers run in parallel to a single relay?

Second question focuses on an indicator or status light. I would like to have a light that remains on when the relay is powered but not triggered by wiring the status light into the 87a terminal and then having it change color or illuminate when the relay is triggered and the 87 terminal fires. Ideally the “triggered” light would be tied across the coils of the fan but that would be too hard to wire up so this is a good (enough) indicator solution. I found something like these:

http://www.alliedelec.com/sloanled-255-12-r-g/70015146/

http://www.dialight.com/Product/Details/557_led_panel_mount_indicators_PMI/5571432203F

If I tie one color into the 87a to show power to the relay and the other color into the 87 terminal to show that the relay has been triggered, that should at least give me an idea of the status of the relay (though obviously not the actual fan), correct? And would that small LED require any sort of diode or resistor? It would be the only thing on the 87a terminal when the relay is not triggered but when wired in parallel with the high-draw accessory fan will it cause issues?

While this all makes sense to me in theory I just don’t understand circuits well enough to have full confidence in the schematic that I drew up in my head.

[bradnic]

That's an awful lot of work and complexity.. what's the issue with the stock setup?

[phenryiv1]

That's an awful lot of work and complexity.. what's the issue with the stock setup?

It isn't there. When I swapped in the 2.7i it had the mechanical fan deleted.

[bradnic]

Gotcha. So why not just put it back? Unless you're tuning for peak hp or trying to make a swap fit who really cares about the parasitic loss?

[phenryiv1]

Gotcha. So why not just put it back? Unless you're tuning for peak hp or trying to make a swap fit who really cares about the parasitic loss?

I don't have a mechanical fan in my parts bin and the parts - new- are in the ~$350 range. While that isn't a back breaker it is not cheap.

http://www.realoem.com/bmw/enUS/showparts?id=BB13-USA---E30-BMW-325i&diagId=11_0616

I have the electric fan already installed and the relay setup is actually very simple to wire up. It is the status indicator lights that are giving me the trouble. I can always forego the status lights (the use of a thermostatic switch in the radiator is fairly bulletproof) but after having the previous setup fail I would feel better with the indicator lights.

[dasmanschaft012]

I don't have a mechanical fan in my parts bin

I have a fan and a 4k mile fan clutch I'd ship you, but sounds like you're already in efan land

[phenryiv1]

I have a fan and a 4k mile fan clutch I'd ship you, but sounds like you're already in efan land

How much? Might not be bad to keep it around if the electronic fan situation fails.

[paynemw]

ABSOLUTELY do a crank scraper and baffle especially if you didn't put new bearings in the bottom end when you did your 2.7i build. I just blew mine up because I was revving too high AND didn't have a scraper. I spun rod bearing #3, which damaged the crank - really only .003 so I would have to grind the rod journals down. Well that removes some coating according to Metric Mechanic and is detrimental to the overall strength of the crank.