I'm in the process of cleaning and preparing an old 2.0 engine for 24hr of LeMons. I have removed all the tins to clean the fins and remove all the trash accumulated over the years. I have removed the front blower section and cleaned the fan as well. Replaced the oil cooler seals. I would like to block off the heat exchanger tubes. If I remove the "J" tubes and block off the holes coming off the blower housing will that help? Is there any advantage to leaving the "J" boxes and running air through the heat exchangers?

Since I have everything off the front of the engine, am I able to inspect the oil pump by removing the cover below the crank? Front oil seal is dry as a bone, should I replace it just for good measure? Any other input is appreciated.

You can block the round holes comming off the side of the HEs with rubber freeze plug repair plugs. If you can't find locally (cheap) I can ship you two. AL

Hopefully the experts will chime in. I had heard that blocking the blower housing air vents interferes with the design airflow and leads to poorer cooling. Not a fact, just what I was told once somewhere.

I believe Jake did some testing and found that plugging them created cavitation and lower cooling ability, but if you replace the housing with a bus housing, the air loss is reduced and there is no cavitation.

Joe - IIRC if you leave it hooked up with the J-tubes to the heater flapper boxes with those set closed, then it vents the hot air off of the HEs up higher in the air stream/engine bay as per the original design & away from the engine for better cooling.

Doing that, you can then remove the heater tubes & block off their feed holes on the heater flapper boxes with that aluminum tape/adhesive sheet.

I can say when my turn key engine came back from Jake the J-tubes were blocked off. I had to remove the blocking plate on one side to connect to the heat exchanger kit for the Tangerine exhaust.

Was it blocked off where the J tube connects to the cast fan housing ?