Help! Cracked Head in my CSi

E9inus Maximus

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Fellow e9ers. I have an issue that requires forum expertise. I had my csi engine fully rebuilt in February of 22 and all systems fully gone through, the car was running very strong for a stock 4 speed with Stahl headers and a mild Schrick 282 cam. This particular problem began a few weeks ago after an enthusiastic 4 hour drive from Miami to Orlando. A few days later I developed a hard start condition with misfire that would disappear after about a minute then a week later noticed I was rapidly loosing coolant until smelling exhaust fumes in expansion tank. Didn’t take long to figure out I had a headache Tylenol doesn’t fix… I just pulled my head off and dye tested it to find these two cracks between my seats. Please see photos. I like that I have a numbers matching CSi but can this area be well repaired or am I better off getting another head and if so, which? I would think it’s been decked at least twice. Repair or replace…tough one, I love that it’s a very original matching numbers car. Help gratefully appreciated @deQuincey @sfdon. I’ll get one today if I have to, I can just as easily be reached on my mobile @ 305-495-1942. Cheers, Dan
 

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Certain of the heads used on our cars were known to have this problem. The head on my car was replaced sometime prior to my ownership, and I presume this issue caused that replacement.

Fortunately, the heads are not numbers matched to the engine and/or to the car. And better yet, the later heads have better coolant passageways and are a known and preferred upgrade to the earlier heads. Do not repair your head. Seek out a head with a 1981 or later casting date on it and replace your head.
 
Certain of the heads used on our cars were known to have this problem. The head on my car was replaced sometime prior to my ownership, and I presume this issue caused that replacement.

Fortunately, the heads are not numbers matched to the engine and/or to the car. And better yet, the later heads have better coolant passageways and are a known and preferred upgrade to the earlier heads. Do not repair your head. Seek out a head with a 1981 or later casting date on it and replace your head.
Hi,
I went to look at the head after posting and realized I was staring at the block but noticed my head is date coded. I’m aware of the usual e9 gremlins, countless hours of restoration, studying this forum and have read tons of your posts as well of which many have been very useful. I think I may have purchased it this way because the head was done but not the bottom end…I’m already looking at an E12 head because I still run my DJet but I’m seeing others that seem as though they work too. It’s an M30 so several head options. Is there an “ideal head” or preferred head to keep my DJet. I suppose upgrading to improved coolant passages isn’t a bad thing. I sourced an original fan shroud and hardware from BMW of Monterey…it is unusually hot here, this car needs the upgrade and I drive the hell out of it. Any advice or options appreciated.
 
It would be interesting to learn if your head (the one that just cracked) is original to the engine/car. There's no way to confirm this 100% because they were not VIN stamped. But you could look for the date stamp on the front left side of the head to see if it is contemporary to the car. I'd assume it is the original given the cracks you just experienced (the earlier heads were prone to overheating). If original, I suspect it would read '72 in a circular shaped stamp/mark. But so many of these heads have been replaced with later heads already.
 
It would be interesting to learn if your head (the one that just cracked) is original to the engine/car. There's no way to confirm this 100% because they were not VIN stamped. But you could look for the date stamp on the front left side of the head to see if it is contemporary to the car. I'd assume it is the original given the cracks you just experienced (the earlier heads were prone to overheating). If original, I suspect it would read '72 in a circular shaped stamp/mark. But so many of these heads have been replaced with later heads already.
Date stamp shows perfect match to build date. I’m assuming I have my original head as I purchased a fully intact car.
 
I'm running carburetors, so I'm not familiar with the various differences in the head applicable to D Jet or L jet or whatever. That said, I don't think you will find an e12 head with an 81 or later casting date, so if you are looking at an e12 head, you are not looking at the head with the improved cooling passage design.

I remember sfdon stating you do not want an M30b30 replacement head. You need to find a later head. I don't recall exactly when D jet morphed into L Jet, but I suspect this means you are not looking for a head from a car running D Jet.
 
You want a fuel injected head with later coolant passages and NOT one that has already been machined past the recommended head height. You will determine the head height by seeing the dimples cast into the head.
 
Hi,
I went to look at the head after posting and realized I was staring at the block but noticed my head is date coded. I’m aware of the usual e9 gremlins, countless hours of restoration, studying this forum and have read tons of your posts as well of which many have been very useful. I think I may have purchased it this way because the head was done but not the bottom end…I’m already looking at an E12 head because I still run my DJet but I’m seeing others that seem as though they work too. It’s an M30 so several head options. Is there an “ideal head” or preferred head to keep my DJet. I suppose upgrading to improved coolant passages isn’t a bad thing. I sourced an original fan shroud and hardware from BMW of Monterey…it is unusually hot here, this car needs the upgrade and I drive the hell out of it. Any advice or options appreciated.
From a drivability standpoint, you are better off with a newer head design, from a collecting and value of the car standpoint, the original head is a definite plus. Advice: Get your original head fixed and keep it on the side while using the newer one for driving.
 
From a drivability standpoint, you are better off with a newer head design, from a collecting and value of the car standpoint, the original head is a definite plus. Advice: Get your original head fixed and keep it on the side while using the newer one for driving.
Thanks & +1 @sfdon for finding me the ultimate upgrade head. ✅
 
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I'm running carburetors, so I'm not familiar with the various differences in the head applicable to D Jet or L jet or whatever. That said, I don't think you will find an e12 head with an 81 or later casting date, so if you are looking at an e12 head, you are not looking at the head with the improved cooling passage design.

I remember sfdon stating you do not want an M30b30 replacement head. You need to find a later head. I don't recall exactly when D jet morphed into L Jet, but I suspect this means you are not looking for a head from a car running D Jet.
Typo, accidentally wrote E12 which is not the correct one.
 
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Newer = Better.

Do we not upgrade our shocks, springs, & sway bars? Buy tires that have better engineering than what was available 50 years ago? Put in faster window motors and change our fuel injection brains to more reliable modern components? Install that 5-speed we've been wanting? These changes, though barely visible, have a positive impact on the use of our pride and joy.

Our cars are, mostly, not museum display items to be admired but vehicles to be driven and enjoyed. Sure, too many changes can alter the basic characteristics that we love about our cars beyond what's reasonable, but I'm not going to let a barely visible date code keep me from replacing my head with the 1984 vintage head I've already bought when the original one fails.
 
Newer = Better.

Do we not upgrade our shocks, springs, & sway bars? Buy tires that have better engineering than what was available 50 years ago? Put in faster window motors and change our fuel injection brains to more reliable modern components? Install that 5-speed we've been wanting? These changes, though barely visible, have a positive impact on the use of our pride and joy.

Our cars are, mostly, not museum display items to be admired but vehicles to be driven and enjoyed. Sure, too many changes can alter the basic characteristics that we love about our cars beyond what's reasonable, but I'm not going to let a barely visible date code keep me from replacing my head with the 1984 vintage head I've already bought when the original one fails.
Well put, I fully agree, I drive the hell out of my car on 17” BBS style 5’s with sticky tires and love every minute of it. True it will never see a museum, but I simply love M30/B30 analog 4 speed originality. Not stuffing a bigger motor or 5 speed in either, I have track cars for that and this car does just fine if you’re not trying to break a land speed record. I’m still having my old head professionally repaired just to keep in case.
Cheers,
Dan
 
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