Just built my first engine and noticed something about the MLS head gasket. The coolant passages vary in size from cylinder #1 to cylinder #4. This would mean that cylinder #1 gets a good amount of coolant and will run cooler, while cylinder #4 will get very little and run hooter/leaner. Not trying to build another engine sooner that necessary, so I did the following:


This is cylinder #1. As you can see, the coolant passages are a good size. In between cylinder #1 and cylinder #2, there are very small holes to cool between cylinders. Left them alone, but next time, I'll add a few holes with a small drill bit


This is cylinder #2. Now notice the coolant passages have gone down some in size. I di dnot change these, as they seem satisfactory from my n/a car. had i gone with boost, I'd likelt widen then a tad.


This is cylinder #3. Notice that one more, the size of the coolant passages has been decreased yet again. These are smaller than the passages of cylinder # 1 and cylinder #2, and will ultimately run warmer from lack of coolant flow.


This is cylinder #4. Notice the drastic decrease in the coolant passages. This is far too small to supply the cooling needed to run effectively for a modified or even a stock vehicle.


Here are the changes I made to bring some balance to the coolant flow in this engine:


This is cylinder #3 bored out. Simply too a larger drill bit, secured the head gasket to prevent damage, and drill the passages out. This should certainly do a better job of cooling cylinder #3.


This is cylinder #4 bored out. Quite an improvement over the original design, and one less flaw to cause failure down the road.


After the drilling, I was nervous about the gasket sealing properly, so I used cooper gasket sealer on the MLS to ensure a good seal. Working great so far!

 

ive notice this on sevral engines that ive disassembled, thos small hole can get clogged pretty easy

what brand is that gasket?

 

You realized they did that for a reason, correct? If you are not in a cold climate, or you dont use your heat it is ok, but the reason they do that is to restrict the coolant flow so the engine warms up sooner.

 

well thats what the thermstat is for.

the only reason i can think why, is because the water flows for one side on the block to the other. So they restric the first cylinder thatsees fresh cool waterso the last one the water is warmerso itneeds more coolant flow to stay cool.

 

Not really. The engine may never even get hot enough to open the thermostat. There really may be nothing wrong with doing this, but my point is that there is a reason the high payed Chrysler engineers decided to do that, do you think they just said "Hey, lets make some holes smaller than others cause we are over paid douche bags?"

Another example of this, when I built my 350, the rebuild kit came with these little metal restrictors that went into the intake coolant ports, and a little paper came with it explaining that some castings had larger cooling ports than others, and the engine may not get up to operating temperature. Mine was not one of the engines listed, so I didnt use them.

 

Yes I figured there was a reason behind it. This head is temporary, so i figured i'd experiment a little.

 

thats debatable