Low oil pressure in a Model "B" engine follow-up

[Marshall V. Daut]

I'm posting the apparent solution to what had been a vexing low oil pressure concern in a friend's professionally rebuilt Model "B" engine with insert bearings in his 1928 Model "A" Sport Coupe. My posted question last week didn't get many public responses (like, ZERO), but I did hear off-line from three knowledgeable Model "B" guys, who offered great advice and printed documentation: Jim Brierley, Colin in Melbourne, Australia, and James Rogers of Dreamwerks. "Greg Out West" also provided some good information on "B" oil pumps and how to improve oil pressure and flow in a "B" block a few months ago when I was looking to modify the Kentz filter system. Past postings on the subject reaped good information and photos, too. But Vince Falter's website information on Model "B" oil pumps provided the definitive answer to my problem. Thanks to all for your input. Each little bit added up to help solve the problem.
Briefly, the problem simply came down to the need to use a Model "B" oil pump in a Model "B" engine. Duh! The problem "B" engine in question here had a rebuilt Model "A" pump with the straight 1/2" pump shaft, no relief. This wasn't able to pump enough oil to feed the oil filter or give a good oil pressure gauge reading. When their fittings were removed for checking oil pump operation while the engine was running, only a blurp, blurp, blurp resulted. Taking advice from the aforementioned experts and studying Vince's drawings and photo of a Model "B" oil pump shaft with a 0.10" relief along its shank, I decided that a Model "A" pump just couldn't provide the needed oil pressure. There was NOTHING wrong with the later Model " A" oil pump in this engine! It just operated differently in a "B" block with its alien non-Model "A" oiling system. Instead, I put in an NOS Model "B" oil pump with its relieved shaft Sunday and was flabbergasted at the improved pressure that resulted! It was so strong, in fact, that the fittings for the pressure gauge and oil filter leaked like crazy, something they hadn't even come close to doing when the Model "A" pump was in place. It took quite a bit of thread sealing and fitting tightening to stop the hemorrhaging of oil. But, wow! Instead of the paltry 1 or 2 psi delivered by the totally stock Model "A" pump (with the round exit holes), the pressure now reads 4-5 psi and steady. What a difference!
One other thing I asked about in my posting, as well as off-line, was whether the orientation of the oil pump drive gear housing made any difference. As readers may know, there are two "flats" on the housing in the area of the exit hole in the lower oil gallery. I turned the housing until one of the two flats was directly opposite this exit hole. I looked everywhere for an answer about orientation of this little devil, but nothing was mentioned anywhere. I assumed that was an answer in itself if the issue had not been raised on this website or mentioned in any Ford or restoration manuals. I can't say if the way I oriented the housing made any difference in increasing the oil flow (doubtful) or whether the change was due solely to use of a true Model "B" oil pump, but the problem appears to be solved.
Not being much of a Model "B" engine block fan, this was new information to me that I'll file away for future reference. Maybe reading the solution here to my problem may help someone else in a similar situation.
Marshall