[66_Cat_Jon]

My 1966 092 heads and 19?? 143 heads have cups or buckets on top of the valve springs. I'm getting the stuff together to have the 092's reconditioned and upgraded for a hyd roller, so new springs, retainers and keepers. Those bucket or cup devices are nowhere to be found. When and why did they become unnecessary, and what was their purpose in the first place?

[b-man]

They are shields to prevent excess oil splash from hitting the valve stems. The factory umbrella valve stem seals and the o-ring seal just below the keepers could only handle so much oil.

Factory Ram Air engines did not have the oil shields.

Installing positive modern valve stem seals (must cut the top of the valve guides) as part of a proper rebuild eliminates the need for them, plus they usually crack and fall apart with most replacement valve springs that are slightly larger in diameter than original springs.

[steve25]

You do not need them if while you are getting the heads rebuilt you have the valve guides cut for positive Viton type seals.

Once thats done you will also not need the O-ring seal that goes in the lower groove on the factory and some aftermarket replacement valves.

[Half-Inch Stud]

All good and true.

I do wonder about using the umbrella cups on the Intakes for least oil bath, yet bare springs on EXH for cooling the springs and stem in an oil bath (bone dry not cool).

[PontiacHO]

As long as you don’t mind a puff of smoke on start up.

[chiphead]

Agreed, exhaust stems WILL pull oil. I was told years ago by a machinist that oil control on the exhaust stem wasnt that important, as there is not much suction drawing oil, unlike an intake stem.

Wrong.

I did a 235 straight 6 and left the exhaust seals off. Guides were in spec and valves were new. This is a shaft mount design where all the rockers are on a common shaft. The shaft carries the oil, not the pushrods. and it puts a lot of oil up top. It smoked at idle, constantly. Installing vitons on the exhaust guides cleaned it up. Lesson learned.

Whenever rebuilding a set of iron pontiac heads, just install modern vitons and ditch the factory shield/O-ring design. On all valves.

[steve25]

Your 143 heads where used in 1967 on the 290 and up hp 400 motors and only in the B body cars .
Theses motors used a 2BBl or the Carter AFB 4bbl.

[Joe-Touring]

I would also recommend the positive viton seals. If you’re running aftermarket 1 piece valves, they do not have the second notch for the factory o-ring. So you would be forced to convert to viton seals. You can even do the machining yourself with this tool:

https://www.summitracing.com/parts/hrs-92040

I bought the comp version, but those went up quite a bit in price. They appear to be the same, however.

I do have a question for you though, I have a set of 143 heads on my 326. Can’t find any real numbers for combustion chamber volume, have you had your heads cc’d? Thanks

[3X24SPD]

I did a low budget rebuild on a 71 455 back in the early 90s.
Pulled out of a car that had been sitting in a pig farm down in MA for I don't know how many years.
It was pretty crusty, but it was free.

Cleaned it all up, hit it with a hone- and installed new rings & bearings.
Lapped the valves, new valve seals- and installed a Warrior 068 cam & 1.65 rockers.
Bolted on a 65 TriPower- and lit the fuse.

Ran pretty good, used to race it twice a week in a 4-speed 65 GTO.

Since then, it's been cycled through 4 different cars- and never so much as skipped a beat or needed any attention at all. Just like the energizer bunny.

I pulled it out of car #3 last summer, to install the new 440 in the 66 GTO. Dropped it in the 63 Tempest to serve as as a mockup for that build while the new 469 was going together.

Before I dropped it in, I decided to spruce it up with some fresh paint & new valve covers. Pulled the valve covers off for the first time since I built it 35 years ago...found this...

[steve25]

Joe since the 67 326 came with the 140 or the higher compression 141 head ( chamber like the 143 head) would think that the head may have been milled some if you where not the one to bolt it on your 326.

The listings for the CCs of the chambers that I see make no sense and especially when you consider that the 143 head was used on the 400s.

The 140 head was said to have 62 CC chamber and the 143 a 52 CC chamber.
A 400 with a 52 CC chamber would have been far above the stated 10.5 ratio.

The deck clearance of .011” sounds right from what I have seen from rebuild two of these 326 motors in the passed.

[3X24SPD]

Pulled the shields off the heads that came off the 428 I had just torn down to build the 440- degreased, media blasted, ultrasonic'd.
Fresh set of valve seals for good measure, buttoned it back up with the fancy new valve covers.
Good to go.

[pfilean]

hen I got my 61 the PO had had the engine rebuilt and new Comp springs installed. Blew smoke on startup and went through a quart every 500 or so. No cups on the springs because the springs were a slightly larger diameter than the stock. I had a valve job done on a different set of heads using the original cups and springs. Guide clearance is not great but within spec. Don't drive a lot as it is a cruise-in car show vehicle. But I don't have to top it off between oil changes. Changes are more because of time than miles. Yes I should have had the Viton seals installed but for how I drive it I'm good.

[peters23]

What is the consensus on installing newer style valve seals?
Should they go on all the valves or just the intakes?
Thanks!

[pfilean]

If you are going to take heads into the machine shop anyway might as well do them all.

[chiphead]

Do 'em all.

[Half-Inch Stud]

Originally Posted by peters23

What is the consensus on installing newer style valve seals?
Should they go on all the valves or just the intakes?
Thanks!

Great Question. Perhaps do em all. Is the right answer. Them long downhills pull high vacuum from both Valve stems. I think