[headhunter86]

Working on 66 389 with 093 heads. Would like to know if there is a poly lock that will fit under the stock valve covers. Thinking stock valve covers will not fit when using poly locks. Or is there another good way of making adjustable valve train without using valve cover spacers.

[thepontiacman]

Might use regular locking nuts.

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[geeteeohguy]

Been using poly locks under the original covers on my '65 GTO's engine for the past 40 years with no issues. Stock 77 heads, press-in stock studs. Not sure of the brand, it's been that long since I assembled it. They certainly aren't tall or bulky....maybe 1/2 inch taller than the original stud, at most.

[headhunter86]

After asking this question I was thinking that back in the day if a Royal Bobcat tuneup kit was purchased, poly locks were part of the kit. I assume stock valve covers could be used with the kit. Thanks for the replies, Ken.

[Goatracer1]

Chevy rocker nuts work just fine.

[Sirrotica]

Originally Posted by Goatracer1

Chevy rocker nuts work just fine.

Not without a washer under the nut, they don't. The Pontiiac rocker nuts have a 7/16 recess made in to the bottom side to seat on the bottle neck. A chevy nut on a stock bottle neck stud will bottom out before you can take the rocker arm down to the adjustment point. A washer is necessary to make a chevy nut work.

Just get the short 3/8 poly locks, there are 2 lengths made. The taller ones will most likely hit the valve covers. Unintentionally I once got the taller nuts, I had to machine the lower end shorter to get valve cover clearance.

[lust4speed]

Agree with Brad. I've always had to use hardened washers under the Chevy locknuts with the 3/8" bottleneck studs (which is just one more reason to toss them and go with the stouter 7/16" studs).

[Goatracer1]

I don't know how I've gotten away without using washers under the Chevy nuts but I've been doing it since the 1960's.

[Sirrotica]

I assume you force it over the bottleneck part of the stud.

Speed Pro/Sealed Power (HT951R) for many years has included a set of 16 hardened 7/16 washers for use under chevy 3/8 inch nuts that come with the limited travel lifter sets.

I've heard that story all you need are chevy nuts for years, in practice it doesn't work, unless your forcing the 3/8 inch nut over the step in the bottle neck studs, or using a washer for a spacer. The upper part of the stud is 3/8 inch the lower part is 7/16 inch. The stock rocker nuts have a 7/16 inch countersunk relief machined into them so they sit below the flared bottle neck stud. Running a 3/8 inch nut to the flared step doesn't get the pivot ball to the correct spot to adjust the lifter with a stock base circle cam. Exactly the reason the Pontiac nuts are taller than the chevy nuts, they have that extra 1/8 inch relief machined in them.

Are you machining a 7/16 inch relief in to a chevy nut like the stock Pontiac nuts, that could work? A stock 3/8 chevy nut is going to bottom out on that step. Running a BBC 7/16 rocker stud will allow a stock style BBC rocker arm nut. Only way your going to run SBC rocker arm nuts on a 3/8 top stud, 7/16 bottom stud is with a washer to get the rocker arm pivot ball in the correct position, Believe me, I've tried it before.

This isn't my first rodeo with this story, I've built, and raced Pontiacs since the late 60s. Mick, (Lust4speed) has had his hands in Pontiac engines for many years also. Most times when there is a technical item, he, and I agree on it, basically from our years of experience between us.

Feel free to explain to me, how you get the extra 1/8 inch needed to get the pivot ball closer to the head to get the lifter adjusted properly, and get the geometry right..........

[Kenth]

I have found one full turn preload from zero lash will place the rocker ball at the same spot on stud washer or no washer under whatever nut used.
I am using CSB nuts w/o washers on my #48 heads.

Also, last time i purchased the HT951R lifters they were just regular HT951 with a different retainer clip for the plunger, certainly no limited travel.

[Sirrotica]

Originally Posted by Kenth

I have found one full turn preload from zero lash will place the rocker ball at the same spot on stud washer or no washer under whatever nut used.
I am using CSB nuts w/o washers on my #48 heads.

Also, last time i purchased the HT951R lifters they were just regular HT951 with a different retainer clip for the plunger, certainly no limited travel.

So Speed Pro/Sealed Power, included 7/16 inch hardened washers, along with the stock style SBC 3/8 inch crimped nuts in their HT951R kits to make the Pontiac valve train adjustable for no apparent reason is what your telling me? Damn they could have saved a ton of money leaving them out. Even though the Pontiac nuts have a recess cut in to them so the bottom of the nut sits below the bottle neck, you can somehow raise it roughly .125 without any consequences? It must be really noisy.

I'm wondering how Lust4speed, Speed Pro, and I can't do this, are we just ignorant fools?

Now, with a 3/8 inch poly lock, they are made the same way as the stock style Pontiac jamb nuts, and have with a 7/16 inch recess in the bottom, that will require no spacer under the nut. SBC 3/8 crimped nuts are flat and do require a spacer to move the rocker pivot ball into the correct position. It's pretty simple, a flat SBC crimped nut can't be made to work same as the original Pontiac nuts with a 7/16 inch recess cut in it.

HT951R from Summit website:

Sealed Power Hi-Rev hydraulic lifters operate at or near zero lash for higher rpms without adjustment, unlike a mechanical setup. They have a reduced internal height to maintain the proper valvetrain geometry of a stock rebuild. They are recommended for high-performance street and racing use.

It seems they are made differently from an OEM Pontiac lifter other than just a retaining clip, and " they have a reduced internal height", which would make them, limited travel?.....

[Kenth]

Brad, FYI i´m not using the CSB nut to the same as an original Pontiac rocker nut.
I´m using them to set the preload on lifters as i would do on a CSB, and that´s what i did on my Pontiac V8. No washers used IIRC from +25 years ago.

Guess there is more than one way to skin a cat, no one has to be an ignorant fool for that! Experiences may differ though.
Still, you can not change the fact that the rocker ball will end up at the same spot on the stud at 1 turn preload washer or not below the nut.

And for the HT951R, when did you buy a set last and disassembled them to check whats inside?
The content may have changed since then?

Picture attached shows one standard (Dana made) HT951 and the famous Sealed Power HT951R i bought and returned.
A set of circlips on a regular set of HT951 for a fraction of the price did the same job.
You´ll be the judge, but i know what i saw, certainly no limited travel on those.
If you know a source of the HT951R lifters you descibe i´m all ears.

Cheers!

[Sirrotica]

Originally Posted by Kenth

Brad, FYI i´m not using the CSB nut to the same as an original Pontiac rocker nut.
I´m using them to set the preload on lifters as i would do on a CSB, and that´s what i did on my Pontiac V8. No washers used IIRC from +25 years ago.

Guess there is more than one way to skin a cat, no one has to be an ignorant fool for that! Experiences may differ though.
Still, you can not change the fact that the rocker ball will end up at the same spot on the stud at 1 turn preload washer or not below the nut.

And for the HT951R, when did you buy a set last and disassembled them to check whats inside?
The content may have changed since then?

Picture attached shows one standard (Dana made) HT951 and the famous Sealed Power HT951R i bought and returned.
A set of circlips on a regular set of HT951 for a fraction of the price did the same job.
You´ll be the judge, but i know what i saw, certainly no limited travel on those.
If you know a source of the HT951R lifters you descibe i´m all ears.

Cheers!

I haven't bought, or used a set for probably 20 years, I know that through the years I've probably used 30 sets of them, they all came with crimped nuts, and washers to place the rocker arm pivot ball below the bottle neck stud, same as a Pontiac jamb nut does. The extra parts came with the kits to make the Pontiac valvetrain adjustable for the limited travel lifters. Since I used poly locks on the engines I worked on, I still have the spare washers from the SP kits in my stash of parts.

I trust that SP has knowledge of what they sell, but maybe they're lying about what's currently in the box. I can't answer of what they currently sell, been out of the wrenching on High Performance Pontiac engines for a couple decades.

Paul K would probably know, as he currently sells, and still builds Pontiac V8s. I have read he has access to the coveted Johnson lifters that people seem not to be able to obtain from other sources. If I was currently building an engine, I would probably contact him for lifters.

I'm done hashing this out, I know exactly what I've done in the past to use SBC nuts on a Pontiac to make the valve train adjustable. I know how SP packaged their lifters with nuts and washers to allow for an adjustable valve train with the HT951R kit. I haven't used SBC nuts to make a Pontiac valvetrain adjustable since I found out about poly locks in the early 70s. The SBC crimped nuts never held the adjustment well anyway on a Pontiac, The difference in double springs and higher pressures over SBC stuff just doesn't hold adjustment with crimped nuts, Poly locks are set, and forget.

It's a crutch anyway because the bottle neck studs have a tendency to break at the step as Mick has already alluded to. It was the cheap way out, back in the 60s, and has been surpassed long ago to ditch the stock studs and use 7/16 studs (BBC style) for better stability. Same as was used on RA IV engines if you're serious about a more stable/reliable valvetrain...........

[Kenth]

The main reason for me using CSB nuts for adjustment of the preload, instead of polylocks is the use of the oil splash/drip baffles under the valve covers preventing oil drip on the cover thru the oil filler cap.
Surprisingly enough the studs have held up for +25 years.

Been through the issue with FederalMogul/SealedPower/SpeedPro HT951R before, seems like they don´t inform the customers (lie, if you will) of the non-existing content in their boxes.
https://forums.maxperformanceinc.com...66#post2476166

Still, in their catalog X-3009 1996 you can read on page 168 under" Lash adjustment directions for hi-rev hydaulic lifters".
3. For Pontiac engines there is a washer and self-locking nut included with these lifters. They must be used to perform the above adjustment. If washer is included, install the washer and then the nut in the place of the stock nut. DO NOT use these washers and nuts on Oldsmobile engines.
Clear as mud on content.

Regarding the washer under the CSB nut i may very well have used one, like i said it was +25 years ago i assembled this engine and have worked well since.