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1275 oil change

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Rut

Rut

Obi Wan
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Exciting topic for sure! First time I've changed oil in a 1275 and I'm using 20w50 VR1. I noticed that on the second quart going in that the rocker assembly was under oil and the oil drained into the crankcase very slowly. Same on the third and the last I poured in as well. Is this normal? When I started her up I had pressure in the 75 to 80 psi range cold and 45 to 50 psi at idle warm. Temp averages about 180 f with the engine running for about 30 min in the garage with no aux fan blowing. Looks good to me, but the oil draining back into the crankcase so slowly got my attention.
Thanks, Rut
 
good numbers all.
 
Don't worry, my 1275 did the same thing on my first fill. They all do it, just pour slowly!!
Scott in CA
 

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On the 1275, the pushrod holes in the block are a bit smaller than the ones in the 948 and 1098. Like 3/8" compared to 1/2". Also, the small bore engines have the tappet chest cavities for the oil to drain into before dropping through the two small "rectangular" slots between the front and rear cylinder pairs tappet bores.

On the 1275, there is a boring (just under 1/2") down the manifold side of the block, from front to rear, that connects all tappet bores and the two drain holes to the sump. So, the oil in the 1275 has a bit more of a restricted path to drain to the sump.

On the 1275s I build for racing, I bore the pushrod holes out to 1/2" using the milling machine and a Cobalt drill bit. This is a bit of a trick, since the pushrod holes are angled at a nominal 4 degrees to the vertical towards the center of the engine. Just a minor adjustment on the mill head, but don't try this on a drill press with the bit straight up and down. You might find the water jacket.

HTH,
Mike Miller
 
Thanks all, that makes me feel much better. My only experience is with various Triumphs, TR3, 4, 6, and this was not the case. I guess my rocker cover gasket is oil tight!
Rut
 
Spridget64SC said:
On the 1275, the pushrod holes in the block are a bit smaller than the ones in the 948 and 1098. Like 3/8" compared to 1/2". Also, the small bore engines have the tappet chest cavities for the oil to drain into before dropping through the two small "rectangular" slots between the front and rear cylinder pairs tappet bores.

On the 1275, there is a boring (just under 1/2") down the manifold side of the block, from front to rear, that connects all tappet bores and the two drain holes to the sump. So, the oil in the 1275 has a bit more of a restricted path to drain to the sump.

On the 1275s I build for racing, I bore the pushrod holes out to 1/2" using the milling machine and a Cobalt drill bit. This is a bit of a trick, since the pushrod holes are angled at a nominal 4 degrees to the vertical towards the center of the engine. Just a minor adjustment on the mill head, but don't try this on a drill press with the bit straight up and down. You might find the water jacket.

HTH,
Mike Miller
Click to expand...


It might be worth mentioning that the only reason we would do such a mod to the block pushrod's holes is for running larger diameter racing tubular pushrods. Bottom line oil drains into the block slow because there not alot of places for the oil to drain down, the pushord holes are it, and it just takes time on a 1275.
 
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