TOPIC: In-line inner water jacket exhaust baffle plate

This water jacket deal is difficult in many ways! As Randy pointed out, we're dealing with 2 (or 3, if you include pre'73)designs of the water flow direction. Plus, it's hard to explain thoughts,(then type it) in a manner that is easily understood to everyone else.

...Frankenmerc, your motor must be a mid '70, Pre '77 design?...im guessing, because you used (plural) when you talked about "closing exit port(s)"....you have 2 holes that exit from under baffle (holes are in the top 2/3rds between bolt bosses...am I corrct?

This is my thought: I will quickly describe my water passage direction on my inner baffle, water enters under inner baffle from a 1/4" hole at base of block, water flows up to top of channel, makes a U-turn, then goes down the other side, and out an exit hole at the bottom, and that hole is slightly pointed upward into the block water exit port. at the very top where it makes a U-turn, there is an 1/8th" hole that connects to the cylinder head cover area. Everybody review their block, and tell me what you have....

my feelings are...you need all the water flow under that baffle plate, that you can possibly get!
Here's what I think when I examine my block: the entry hole at the bottom..it can be enlarged by about an 1/8th of an inch. Going with the flow of water, it then reaches the top at the U-turn, that is where that 1/8" connector hole goes into the cylinder cover area..i question, why is that hole there...is it a pressure balnce passage?...is it helping to keep water at the upper most part of water jacket..where my telltale port is? I don't understand what the real purpose of that connector port is. NOW, the water makes its U-turn at the top and goes down the jacket that runs along the bottom of the cylinder, then my water exits out a hole (slightly smaller than 1/4") into the exit water jacket...my exit hole is drilled on an upward angle into that exiting water jacket.

...SOOO, my exit hole is smaller than entry hole, the exit hole is also drilled on an upward angle, into the out going flow of water in the exit jacket. Earlier, I questioned if this (angle of exit hole)might have some "siphoning" effect..I've ruled that out..if that hole went upwards, then made a down-turn, then you get a siphoning effect...far as I am concerned, the water trying to get out from under baffle, is being impeded by the out going water flow...your trying to push water upwards, into the opposite direction of the out going water.....

so im left with: an entry hole that can be enlarged, a connector port at top of jacket (remember, connects to cylinder head cover area just below where telltale port comes out the top of block)..a connector port I have made no conclusions on...then an exit hole out bottom of baffle jacket that is smaller than entry, and pointed into the flow of out going water...

...for now, I am going to forget about the connector port at the U-turn..the port that connects to the cylinder cover area.
I know I can get more water in...THE QUESTION IS, how to get more water OUT...I've been looking, I've been studying...the block and baffle design leaves little opportunity...not much meat on the bone to work with..LOL..im looking for a way to get water out of there..

Thanks for taking all the time to write up the posts atomant.
I will be reviewing your posts a few more times and inspecting my block(s) and reply.
I'm thinking you are probably correct regarding the small hole at the top in that it's mission in life is probably to keep an air pocket from forming at the "U-turn" and shouldn't be enlarged.
doc

...there ya go Dr! Just as I said previously, it takes everybody's input! You basically just answered the question on the small passage at the top! Somehow I figured that little passage was critical..like I said (a balance port)...but I was suggesting "head pressure" between the exhaust jacket and the cylinder cover water. It never occurred to me about an air gap at the top...and that's exactly why they moved the telltale to the top of block too!
Now I think all I need to figure out is how to get better water flow out!

Hi guys,
Just an update, I am having gaskets made from a higher temp material, good for 500 F continuous.
I will also be using a junk block to drill a passage from the top of exhaust waterjacket to the exit waterjacket and cut down the wall that makes the flow a u shape. It looks to me there is a perfect spot to do so. All water will flow in and exit at top, similar to how the cylinder area is done. I believe this will result in water being less likely to boil where it is now one larger column not seperated into two smaller columns and the water will flow top to bottom so any given volume transits trough faster , just up and out rather than having to go up then down as is now. Water will also have better contact with the baffle plate to keep it's temp down.........
More to follow. S till can't get pics small enough to post.
Randy

Randy,
If you send your pictures direct to my email I will reduce them to a size that will post.
I'm really interested in exactly where you are drilling and enlarging, but I'm not understanding your explanation. Probably my bad, but I do better with pictures.
Doc