No start turned into bigger problems

[Train67]

I rebuilt a BMW 4 cyl M10 (from a '84 318i) with a 2.0L crank, 91 mm 9.6:1 pistons, 288 cam, port fuel injection with 234 cc injectors, running MS (microsquirt). The engine has never ran since being rebuilt.  I had trouble getting it started with MS (MS noob) but finally got it running, had good oil pressure and brought it up to 2000 RPM until it warmed up to break in the cam.  The valves seemed to be a little loud so I shut it off, checked the clearance and all seemed good with 1-2 about a thousdanth off. The noise was still there when I started it again so I went to check the valves again and found drops of coolant in between the exhaust valves for cylinders 2 & 3.  WTF.

The coolant was about <1/4" down but I assumed that was from burping the system since it's the first fill. Engine oil level did not change.  Compression is 185 on cylinders 1,2,4 and 210 on cyl 3 (rechecked it 3 times).  Oil pressure was 50psi and no weird noises while cranking. I'm not sure what the noise was or if it had to due with the engine tune, or something mechanical. 

Any suggestions on troubleshooting the coolant issue?

[Mike Self]

48 minutes ago, Train67 said:

and found drops of coolant in between the exhaust valves for cylinders 2 & 3.

Where did you see the coolant--in the valve chest (where the valves, cam, valve springs etc are)?  Was the coolant just gathered around the bottom of the valve chest, between the two exhaust valve springs?  And are you sure it's coolant and not just moisture?  

 

Any brown muck in the oil--the foamy mess when coolant gets in your oil?

 

mike

[Simeon]

It might be a funny question but are you familiar with M10 engines? Compared to many others they always have a ‘sewing machine’ type quality of noise. 

 

I am with Mike that is could be condensation under the valve cover from a cold start. How’s the weather been recently?

 

 I would run it for now and keep a careful eye on everything. Note the coolant and oil condition regularly and when you change your break in oil have a good look at that before I would panic. Compression looks good and the spec. sounds like a lot of fun!

[Train67]

9 hours ago, mike said:

Where did you see the coolant--in the valve chest (where the valves, cam, valve springs etc are)?  Was the coolant just gathered around the bottom of the valve chest, between the two exhaust valve springs?  And are you sure it's coolant and not just moisture?  

 

Any brown muck in the oil--the foamy mess when coolant gets in your oil?

 

mike

The coolant was in the valve chest near the center can journal and exhaust valve springs (red circles in pic). I’m pretty certain it is coolant because I am using the blue BMW coolant and the drops were definitely blue. No foamy muck in the oil, looks clean and level is correct. 

 

The coolant was clear and blue and not churned with the oil. Are the head bolts supposed to have thread sealer?  

[Train67]

8 hours ago, Simeon said:

It might be a funny question but are you familiar with M10 engines? Compared to many others they always have a ‘sewing machine’ type quality of noise. 

 

I am with Mike that is could be condensation under the valve cover from a cold start. How’s the weather been recently?

 

 I would run it for now and keep a careful eye on everything. Note the coolant and oil condition regularly and when you change your break in oil have a good look at that before I would panic. Compression looks good and the spec. sounds like a lot of fun!

I know these motors are a little noisy so I assumed the noise I was hearing was a bit louder than normal because I have no windshield or hood on the car at the moment (project car). Now I am thinking it was some detonation happening because of the tune. I would love it to be just condensation but everything was clean and dry before starting it and the coolant drops are clear and blue. 

[Simeon]

No coolant will come from head bolt threads. You can get oil up the outside of the rearmost head bolts outside of the cam cover. 

 

If it was clean blue coolant then it still seems unusual as you would need a significant crack to see it up there. A crack into the chamber (with all the usual signs) would be much more typical. 

 

How about getting a cooling system tester and pressurise the system and watch the head? If it is cracked that bad you would see the seepage. 

[Train67]

Thanks for the input. I’ll do a cooling system pressure test and cylinder leak down and see what happens ?

[Train67]

I pressurized the coolant system and saw coolant coming from the center journal of the exhaust rocket shaft. It’s dripping down either side of the journal. Is this a crack in the head or gasket issue?

[Simeon]

What method did you use to tighten down your head? Anything other than a factory style head gasket used?

[Train67]

I used a Cometic gasket and tightened it to 60 ft lbs in 3 steps. This was the first time I ran and warmed up the engine. Checked the manual and it says another 25deg after engine warm up. Do you think that will stop the seepage?  I’ll give it a try. 

[Tommy]

I've never seen anything like that but my bets are on the Cometic. I've heard nothing but trouble with them. Throw there an Elring "tii schneidring" gasket and see what happens. They are pretty much all you need for any tune-up.

[Train67]

Pulled the head bolt and found coolant at the bottom. There appears to be a path from the water jacket to the bolt threads. Time to pull the head...

[Einspritz]

Before installing the head, did you use a tap to clean out the threads for the bolts? it is rare, but I have seen where the oil was not cleaned out and when the bolt was installed, it "hydro-locked" and cracked the block.

 

Perhaps that is how the coolant is getting up to the head of the bolt.

[Train67]

It was a top to bottom rebuild and the threads were lightly coated. If hydro locked then area was fatigued and ready to go and I was the lucky one. Cracks there seem likely though. Praying it’s just the gasket 

[Buckeye]

Hope that you will find is just the gasket. Next time use OEM or Erling head gasket and use torque and angle method.

That 60 ft-lb torque in 3 steps was for old gasket and gasket technology of 60 and 70's .

Instruction from reputable manufactures tells you to use torque and angle and even service bulletin published by BMW in June 1986 says so.

4. Service-Information - Group 11, Engine June 1986 (Pdf file)

Let us know what you find out and Good Luck.