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Had this over in the Bronco forum and Greystreak92 suggested posting it here. Would appreciate what someone thinks. Mr.john60

84 Bronco, 6 cylinder 300:
I touched on this in one of my other posts, but probably need to clarify it more in a separate thread. When I pulled my engine apart I noticed that the cooling ports on the intake side of the engine in both the head and block dead ended. In other words, the ports didn't match up. Since a cause of broken rings can be heat and stress as well as insufficient ring gap clearance, I am wondering if the coolant has enough circulation to do the job as intended. The flow of the coolant is from the pump back around the cylinders to the rear of the engine and then up through two main ports and forward through the head and out to the radiator. My questions are: 1...Is someone familiar enough with the layout of the head and block to tell me if this blockage of coolant on one side of the engine is as it should be? 2...If I were to open up the ports on the valve side of the engine to each other, would it screw up an engineered design? 3...I noticed that the ports on the opposite side of the engine were closed off by the head gasket with only a small hole in the head gasket, is this the original design? 4...Would opening up any of these ports decrease the efficiency of the cooling system? Thanks....mr.john60

 

fords reason for ending the production of the 6 is that they had problems keeping the temp even across all cylinders. This led to bad emissions. I have not had one apart, but many on here have. Someone will be able to help.

 

I don't think those holes are really supposed to be coolant passages. They are probably just casting holes that had to be put in to get all of the cast out. The later EFI engines are the same way. I suspect that if you opened them up to allow coolant flow you would overheat the rear cylinders because the coolant will take the path of least resistance. Instead of flowing all the way down that side of the block, it will just come in the front and head up through the holes. With the passages blocked it is forced to go all the way to the back, up into the head, and then all the way to the front. It isn't the best way to do it, but it's the best way to make sure all the cylinders at least get a little coolant going around them.

 

Greystreak & Peppermint,
Thanks for the comments. What you say makes sense. One problem with thinking you are intelligent is that you tend to think you are smarter than those people that are intelligent; such as engineers and the like. On my behalf though, I will say that I do believe that my sense of humor is usually of a much greater and superior scope than most engineers I have met. They, along with my wife, just think I'm weird. I'm also much more humble. and better looking. and.......never mind, the list just goes on.
What I will do then is make sure that the passages in the rear of the block and head match up well and and try to make sure there are no restrictions to the flow of the coolant. Thanks ever so much for your help. Mr.john60

 

The only time I've seen bad problems with 300's overheating when all was mechanically well [eg. no cracked iron or blown gaskets] has been when the radiator was either undersized or clogged up. My van had dealer installed A/C but they left the smaller "no A/C" radiator in place. It still worked but when the outside temp was above 95deg it did run warm [if not hot] with the A/C on. I did a homebrew acid bath and cleaned out the 20y/o scale from the radiator and that dropped the temp a little but it still ran warmer than I'd like when towing. Installed a new water pump with the backer plate on the impeller and that took the temp down to a reasonable level. The old pump was still in perfect shape but obviously the modernized impeller on the new pump flowed much better.

1yr later the old radiator sprung a leak so installed a new larger radiator [with A/C version] and the temp dropped considerably. Even towing in 100deg heat with the A/C on it's fine and dandy. Recently a buddy's van was having overheating problems and it turned out to be a clogged radiator. We'd bought a new radiator for him but he wound up selling the van before it ever got installed. it's for sale if anyone needs one, fits 75-91 vans.

You can also install an aftermarket transmission cooler and bypass the in-radiator cooler altogether. This will cool your tranny better in the summer and take some load off the radiator. If you live in the frozen north leave the radiator part connected as it helps warm the tranny fluid to a proper temp in the winter. If you do a lot of towing an engine oil cooler is a very good idea. Many trucks/vans came with these stock if you ordered the factory towing package. If you install an aftermarket oil cooler make sure it has a temp controlled bypass valve so oil doesn't flow thru the cooler till it's warmed up.