Blown head gasket with a big suprise
 

A little backround to get started. I bought a 97 ti a few months ago with 140K on it. I ran it for about 6k miles and one day it died coming back from lunch. Coasted it to a parking lot and noticed the temp gauge pegged. Towed the car home and started to diagnose the problem. This is my second ti and I had blown the plastic coolant hose on the first one. I figured there was a good chance that this was my problem again. When I filled the radiator to try and find the leak, I got a check engine light for cylinder #2. Pulled the plug and noticed coolant in the cylinder. Blown head gasket! Read up on it I decided I was gonna attempt to replace the head gasket on my own. After finding some work arounds for not having BMW special tools (ask me if you have any questions about these) I got the head and cams off. First thing next morning, I take the head to the machine shop for pressure test and resurface. As I head to the machine shop, I have one nagging question......there's no rear coolant hose on the back of the head! After a little research, I realize someone has put an M42 head on my M44 block. By the time i realize this, the machinist is already working on my head. I've already purchased head gasket kit, coolant hoses, thermostat, ect. My question is what are my best options. I've seen a lot of people asking about M42 heads on M44 blocks, but no one who has done it. Is it worth putting it back together, do i try and find a M44 head and sell this one, is this the reason my head gasket blew? I'm a new member of this forum, but have viewed the website in the past because of all the great information you guys provide. Any help/suggestions are welcome. Rich

OK, the engine seemed to be running ok prior to loss of coolant, so I decided to put her back together since all the work was done and a majority of the parts were already ordered.
Two real questions unanswered. 1) Head gaskets (M42 & M44) are pretty much the same. Only difference is (3) little oil holes between the cylinders in the M44 block, (6) in the M42 head. Haven't really found out anything on what they go to, but hoping they are necessary for the springs,cams,...? Will use the M44 head gasket cause it will create a better seal over the holes. 2) I believe he M42 ? sensor is read of the exhaust cam while the m44 head uses the intake cam. I have the timing chain cover for the m44 and the sensing wheel was on the intake cam. Now, it is worth noting that I did notice some rough starts of the car in the past. The timing sprockets are slotted and are suppose to be bolted to the cams in the center of the slots. My intake sprocket was turned 1 tooth clockwise. Anyone know the sweet spot of the m44 sensor on m42 intake cam (if there is one).
Like I said, it was running prior, work was done, parts were ordered, and I could really use the car now.
I let you know how bad it turns out after the weekend. lol

Well, I put the car back together and the cooling system is working great with no leaks. It runs good when at speed but there seems to be a miss as the engine sputters a little at idle. I'm gonna go over everything to make sure a sensor isn't plugged in or a vac line isn't connected. Again, the car can be a little to rough start at times, but I'm sure that has to do with the camshaft sensor and the different locations on the m42 and m44 head.
One question I have has to do with the plastic coolant outlet flange (11531743679) on the back of the m44 head. I know the main line from this piece goes to the heater, but where does the secondary line go. The m42 head doesn't have this piece and the hose attaches directly to the head. There was a coolant line from my m42 head that was blocked off and I thought maybe this took the place of the secondary line of the outlet flange. Does anyone remember where the little 1/2" line off the rear outlet flange goes?

Sorry for the late reply. I know 100% that M42 block will work with M44 head (my setup). Also I know 100% that a M44 block works great with a M42 head since Danny has my old M44 block and runs his M42 head on it. No issues and we are stroker motors 2.1L on high boost

darn, robnhod, that really sucks! sorry you had to deal with that. looks like things worked-out okay, though.

thanks for the detailed analysis!

So do you still have the m42 head on your car? Did you have anymore problems with the car? Let me know bc Im having the same issue :frown: