Re: 1955 Oil Pumps

Posted by Muir On 2017/12/31 15:47:11

Just my two cents worth - I've just done the Olds oil pump conversion on my 374 and it is positively brilliant I did about the hardest test you could for an old car - I drove it downtown in rush hour, no low pressure issues whatsoever.

Now, adding something a little more illuminating here - my 61000 mile 374 measured .045 wear on the mains. The bearings were absolutely munted. Interestingly it had had "020" stamped on the counterweights, so it looks like it's already been ground sometime in the past.

Had a spare motor that came out of a 58000 mile original car - BUT this one owner car had been parked up in 1966 (levelizer issue). The crank was around .002 wear so in really good shape, though again the main bearings were through the copper to the backing.

What this tells me is that a low owner car is more likely to have had things like regular and more frequent oil changes and possibly more sympathetic driving that would've helped considerably to offset massive wear.

I get the impression that the oil pump (and possibly the galleries) were on the marginal side when designed (fine for a less stressed low comp straight eight with double the sump capacity though) and with old unchanged grubby oil (especially the raw crude that was available back in the day) the V8 just clogged the galleries and the pump a little too much and with a revvy, High comp V8 that people drove pretty hard it just pushed the marginal capacity oiling system over the edge.
The oil pump conversion kit and with vastly superior oils available today it's really now no issue.

You could even think ditching the silly bypass oil filter that stresses out even more the oiling system. Filters about 10% of your oil and syphons off a litre out of one head that the poor old oil passages have to cope with. Dealer handbooks advise that after installing a bypass filter to advise the customer not to be concerned that the oil pressure warning light now comes on at idle. Friend with an early Landy had a measured pressure gauge and after removal of his bypass filter oil pressure raised 9 - 10 pounds at warm idle. No wonder there were oiling issues.

Merry Christmas and Happy New Year too :)