While I have the head off...

#1

Hello everyone. I’m new to the forum, and while I’ve been reading many posts for technical assistance, my build is moving along so it’s time to officially join the community. B)

While at an HPDE at Chuckwalla Raceway in March my headgasket blew, which resulted in a cracked head. Long story short, I have a re-manufactured head on the way, and am researching what should be done while the head and other components are disconnected.

I’m doing quite a bit of clean-up, removing quite a bit of sand and dirt from the last event being cancelled early due to severe sand storms, and am looking at removing the heater core, and bypassing the hoses.

The A/C system is long gone.

Other than cleaning up, removal of heater hoses, and bypassing heater core, are there other projects that you would suggest while I’ve stripped things this far?

Thanks,
Jason

#2

2 studs are used to fasten the thermostat housing. Remove the top stud and replace it with an 8mm bolt of appropriate length. This will make it much easier to R/R the tstat housing in the future. Otherwise the tstat is a bugger to remove because a temp sensor abuts the fuel rail.

Remove the aluminum pipe at the back of the head. Fab a piece of aluminum to block the port off. Block off the other end of the hose at the tstat housing.

If you’ve not removed the hoses to the throttle body, do so.

Remove the hose barb that goes in the block near the starter. Put your OEM oil pressure sender into that hole. Use the OEM wire harness connector. Now you have a coolant pressure switch.

4 metal pipes go into the base of the throttle body. Remove them, clean the surfaces, coat in JB Weld and then insert them back in.

#3

I definitely need to do some of those as well Ranger. Thanks for the ideas.

#4

Your head is already configured for the thermostat bolt mod and block off plate is installed. I have a plug for your deleted coolant lines and JB weld for the throttle body fittings.

#5

Thanks for the helpful tips Ranger! I’ll take a further look at things tonight, as I’m still researching what will need to be capped off at the thermostat and coolant resevoir. I have a late model 325i (91), which has the T-hose setup, so the standard kit that provides the plate for the head, and the screw cap for the thermostat won’t completely cut it.

With regard to the coolant pressure switch, I assume I’ll just tap off the OEM wiring harness and run that to an aftermarket light, or is it best to pull from the back of the cluster?

Much appreciated!

Jason

#6

[quote=“coastaljay” post=66593]Thanks for the helpful tips Ranger! I’ll take a further look at things tonight, as I’m still researching what will need to be capped off at the thermostat and coolant resevoir. I have a late model 325i (91), which has the T-hose setup, so the standard kit that provides the plate for the head, and the screw cap for the thermostat won’t completely cut it.

With regard to the coolant pressure switch, I assume I’ll just tap off the OEM wiring harness and run that to an aftermarket light, or is it best to pull from the back of the cluster?
[/quote]
As far as I know there’s nothing unique about late model cooling that makes blocking off the back of the head more complicated.

Clip the OP wire off of the OEM wiring harness a couple feet from it’s end. Then use that wire and connector to connect the sensor to your aftermarket coolant pressure warning light. When triggered the sensor will ground your warning light.

#7

Jason,

Just after the “T” in the coolant line that runs to from the resevoir, thermostat housing, and to the deleted heater core, install a 1" PEX plug. Cut line just after the T on the heater core side to install with hose clamp. You’ll find the PEX plug in the plumbing section at Home Depot. Thanks to Michael Osborne for this tip.

Cap the back of the head with an aluminum plate and OEM gasket (or anaerobic gasket maker).

#8

I found some higher quality hose at the parts store and eliminated the need for the old T hose. I welded the aluminum tube at the back of the head shut. I petitioned Ireland Engineering to make us a silicone hose for late model heater delete but they want about 30 people to call/email them for that to happen.

#9

Ranger - I was referring to the Heater Core piping being different in the late models. You previously mentioned a heater delete kit, but it appears to be specific to the early model setup, as late has a T setup as shown below. I’ll be making a trip to home depot with the pipe from the back of the head to see if they have any plates that might do the trick.

With regard to the hose barb you’re referring to for the new location of the oil pressure sender, do you mean the one small hose that’s connected to the block at cylinder 6, shown below? What did you use to replace the moved oil pressure sensor? I’d ideally like to have a warning light for coolant pressure and oil pressure. Gauges with readouts would be for WT, OT, and possibly OP.

The 4 metal pipes in the base of the throttle body you mentioned - I only count two… See below:

Fishman - The PLEX plug is an interesting idea, but I’d prefer to eliminate the hose all together to reduce failure points, and the hose is looking quite weathered.

turbo329is - Where did you run your aluminum piping? From the coolant reservoir to the thermostat?

Forgive my confusion… the motors been apart since March, and while I’m sure I can piece everything back together with some sense and the bentley manual, it’s difficult to reference when the parts are on the floor of my garage.

#10

Found the attached late model cooling system diagram.

Ranger - the hoses that can be removed from the throttle body are #18 and #19? Would I be correct to assume that #19 is what in a typical OEM setup, connects to the head? If so, what is used to cap off the throttle body side of #18? If these hoses can be removed, what is their purpose?

#11

You can’t eliminate the coolant hose to between the heater core and thermostat housing because it also runs to the coolant resevoir. If it’s weathered, you’ll need to replace it. You might be able to find a different hose that will wotk, but the seems like a lot of work. The PEX plug works extremely well and is nothing to worry about with a good condition hose.

#12

That was a fine couple of posts.

Re. Steel pipes to JBWeld. Lets compromise. Looking at your pic it’s 3 pipes, not 4. The 3rd is on the other side of the tbody.

Re. Late model hoses. Well look at that. I guess I never really understood how late model reservior’s connect to the system. So just run a single hose from reservior to tstat or turn that T into an elbow by plugging one leg.

You could always go to an early model reservior to cut down on hoses. You can do that by either getting an early water pump, $50 new, or T’ing into your water pump’s return. Either idea probably reduces a 5’ hose run down to 2’.

When a person has a coolant pressure switch there’s more freedom to apply imagination to the coolant system because if your idea ever starts failing you’ll know immed.

Also, don’t forget to drill a very small hole in the top of your thermostat. That allows you to bleed the system w/o having to wait for the engine to warm up.

Re. OEM OP port. Remote a hose from the port to your fender and then put in a 1/8NPT T that allows you to have a pressure sensor and pressure switch. I have an adjustable pressure switch set to ~20psi but there’s no school solution.

Get a piece of SS -4AN hose in 16-24". Then 1/8NPT adapters for each end. Finally a 12mm x 1/8NPT adapter to connect hose to block. This last is the hardest to find.

Re. tbody hoses. Yes #'s 18 & 19. They warm the tbody for cold weather “warm up” operation. They don’t need to be capped at the tbody, just at block and tstat.

#13

[quote=“Ranger” post=66615]So just run a single hose from reservior to tstat or turn that T into an elbow by plugging one leg.

[/quote]

The T hose is expensive so just replace it with a single piece of hose. I used some stiff double layer red outside blue inside hose that looks like really thick compressed air hose.

There’s nothing wrong with the late model system.

pics in a few hours maybe.

#14

Well… Not much luck at home depot or the local auto parts store. Home Depot no longer carries a 1" PEX cap, only up to 3/4", with nothing else similar available. Nor, do they carry any hoses that would be sufficient for the job. :angry:

I’m tempted to get the kit from AKG that Ranger posted not too long ago (see below), mostly to simply the job and get it over with, but the overnight shipping I’d need to be able to cap the back of the head by this weekend, would run me $75 shipped!! They’re in IL I’m in CA - doh!
http://www.akgmotorsport.com/catalog/catalog.php?category=e30%20Engine%2FDrivetrain

I did find a section of 1/8" thick aluminum stock at home depot that I might go back and get for a custom fab job. The width is oddly enough exactly as wide as the widest point of the aluminum pipe i’ll be removing from the back of the head. I’ll just need to cut it down a bit to fit, and figure out a custom gasket. Anyone have a better solution, or story on how they custom fab’d theirs? Please share!

Anyone have an opinion on running a mixture of water and Redline’s Water Wetter vs typical coolant/water? I’ve run a few HPDE’s and maintained a decent boiling temperature, as far as I can tell anyhow, given my old reading is from an OEM dummy gauge.

Re. Steel hoses - I looked at them again, it all makes sense. Thanks for clarifying Ranger.

Re. Removal of hoses from TB - I assume the breather hose from TB to valve cover needs to be retained?

Re. Drilling the hole on the top of the thermostat - This feels like a silly question, but wouldn’t this cause it to constantly leak out the top? I’m use to using the bleeder screw, which doesn’t take that long… If it’s safe and saves me time, then I’m all for it though.

Re. OEM OP port. I didn’t have enough time to source all these parts, but I’m intrigued by the idea. Do you have any pictures of the setup that you’d be willing to share? What senders did you use? I picked up a new e30 m3 OP sender for dirt cheap that I’d love to use if possible.

turbo329is - Please do post pics of your custom hose. Where did you pick it up? What’s the diameter?

My remanufactured head arrived today! Looking forward to starting the car again in the next week or two. Thanks to everyone for your tips and guidance so far! :slight_smile:

#15

Re. blocking back of the head. You’re making this too hard. Buy a piece of thick aluminum and use the AL pipe as a model to cut the blocking plate and drill the two holes. Then just reuse the gasket from the pipe or slather in some RPV goobage.

Re. blocking off the hose at the tstat. For now just cut a short piece of hose, but a great big bolt in it, slather in goobage and put on a hose clamp. Later do something more elegant.

Re. drilling hole in top of tstat. Drill the hole in the tstat, not the tstat housing you goof.

Re. Remoting OEM OP Port. This is easy. The block has a 12mm port. Buy a piece of -4AN SS hose in appropriate length and the 1/8NPT T. Then get the adapters to make it work. A pic would only show a length of SS hosee and some mystery fittings.

Re. Waterwetter. Its worth doing. There’s a number of products that all do the same thing…they’re wetting agents and they reduce water surface tension so more water get’s in contact with surfaces. They also contain anti-corrosion additives.

#16

Took some pics and then realized my micro sd adapter is 90 miles away. ID of the hose is 1in or a little more. I bought 3 ft and used about 2. It’s just a hose that goes from the reservoir under the airbox and makes a sweeping curve behind the alternator into the bottom of the thermostat.

Picked it up at the real local car parts store. The store is badly lit, has anything you need in back and still has naked girl calendars on the wall from the 80s from wurth and mac tools.

I just changed the t-stat in my iX. It came with a hole and a crude check valve already in it. Was on the shelf at O-reily for about 16$ including the o-ring.

#17

Here’s what I built today from Surplus Depot: M12 1.5 AN to 1/8th NPT adapter -> to oil distribution block with 2x 1/8th NPT ports for an OP Switch and OP Sender. Still researching what switch and sender to get.

My main goal for this week is to get the car running, and will probably just use the M12 1.5 AN fitting and cap it off so I can move the OEM OP sender to the other side of the block.

Will post pictures of the whole setup when completed.