[67Fbird]

So ...when did con rod bearing makers decide oem spit holes were no longer needed? My OLD (circa 1990) build used clevite bearings that did have spit holes...my NEW bearings have NO hole. I am debating about machining the hole at the edge of the bearing via simple fixture? Ideas? pro's cons?

[johnta1]

You don't need them.
Pontiac quit putting the holes in the rods early 70's.
(there's a service bulletin on it, would have to look for it)

[Sirrotica]

I'd have to agree with the engineering bulletin (Although I've never seen it). There are almost no other brands of V engines that I have worked on that have those holes.

Some earlier inline engines had on those holes in the top of the big end bore so as to lubricate/remove heat, from the bottom of the cylinder, but as years went on they also went out of favor. I don't see them in engines any longer, as years of development have proven it's an unnecessary machining step that can be left out, saving the manufacturer a little money, but not affecting the longevity of the engine. The oil being thrown from the crank seems sufficient to take care of the lubrication of the bottom of the cylinder.

[steve25]

In terms of 60s era motors, and If I am not mistaken only the factory 151, 326, 389 and 421 Rods had the camshaft oiling holes.

[Sirrotica]

A 151 engine came out in the mid 70s, derived from the last design of the inline chevy 6 with 2 cylinders removed. Pontiacs response to corporate making them use the unreliable aluminum Vega engine in the Astre and Sunbird models. Earlier in life the 151 was a 4 cylinder only available in chevy IIs and displaced 153 cubic inches.

I believe you're referring to the 194 slant 4 engine that was 1/2 of a 389?

But, the 326s, 400s, and 428s starting in 1967 still had the spurt holes and they were discontinued in the early 70s. I know that 1972, from memory, didn't have them, as I had to put a couple rods in a customers 72 400 that didn't have spurt holes, but the earlier reconditioned rods we bought did.

From that example in 1972 they were not machining them into the rods, but many of the 67 to 70 engines still had them, again from memory, not infallible by any means.

I just returned from a trip to the garage to look at parts stash, 69 428 rods have the spurt holes, 73 SD NOS rods don't, so somewhere in the middle is the cutoff, and from memory back to the late 70s the customer that brought me that 72 400 did not, so further narrows it down to 69-72 is when they deleted the spurt holes.

[steve25]

Yes, 194 inline 6 is what should have come out of my finger tips!

[67Fbird]

1968 400 has them....just wondering with all the hft cams rounding off.... might re think the idea???

[Sirrotica]

Originally Posted by steve25

Yes, 194 inline 6 is what should have come out of my finger tips!

The Pontiac inline 6 is a 215 in 1964 and 1965, that is basically an inline chevy that falls short of 230 cubic inches, but is more than the smaller 194 that chevy used. It was only available in A body Tempest/Lemans cars. It was a stop gap until Delorean got the 230 OHC 6 out of engineering, and into the car chassis.

The 194 first appeared in 1961 and it's final year was 1963, available in only Tempest and Leman cars. It was essentially a 389 right bank, cutting off the left bank of the block , and using a slant 4 configuration. It shared many parts with the 389 and if you divide 389 by 2 the displacement is 194.5, which Pontiac marketed as a 194 cubic inch slant 4.

See below 215 inline 6 picture:



See below 194 slant 4 picture:




They are 2 completely different engines, one a 6 cylinder that was designed by chevy, which Pontiac used for 2 years as a fill in proceeding the 230 OHC debuted in 1966.

The 4 cylinder was an attempt at using one bank of a 389, as an economy engine, without completely different tooling for a new 4 cylinder. Debuted in 1961, and terminated in 1963. Without a balance shaft, it idled like a paint shaker, and needed special motor mounts to absorb the vibration at idle. It was also notoriously hard on timing chains/gears, prompting Pontiac engineers to design a specially hardened timing set just for the 4 cylinder usage.

The above pictures, and descriptions are just to keep the Pontiac engines straight, and correct.

If John has time to find the bulletin, we will know for a certainty what year the Pontiac Stratostreak V8 stopped using oil spurt holes......

The FT cams were fine even after the discontinuation of the spurt holes, something changed in and around 1977 with manufacturing of the cam blanks, or lifters.

Later on gov't mandates for removing anti wear additives from motor oil also had some effects on cam lifter wear, When they started going flat at a wholesale rate, it was all GM cars that stated having cam lobes going away, not just Pontiacs. I seriously doubt re instituting spurt holes will have any measurable effects on flat tappet cam/lifter wear........