Valve Adjustment & Valve Closure Rate

[JoeHall]

The 62GT had 16,347 miles since the last valve adjustment. So, in prep for the trip to Maggie Valley, TN later today, I adjusted them this morning. I last set them around .027" for the intakes, and .029" for the exhausts. Today, the tightest intake was around .024, and the tightest exhaust was .016". I set them today at .028" and .030". All measurements are when cold. It now has that nice light tap at idle, many of us are soo familiar with.

My experience is when the exhausts get down to less than around .005" clearance the motor will start to rock at idle, so it had plenty of clearance left this time. Should be good to go for another 20,000 before the next adjustment .

Almost forgot to mention, it has hardened exhaust seats. My experience is that they close at about half the rate the OEM ones do.

[PackardV8]

Hi, Joe,

As always, you can be relied upon to produce factual data. You also put more miles on your cars than most anyone. The 16,347 in a relatively short time span is rare among Studes today. Losing .013" on the exhausts is huge, much more than I'd have expected with hard seats.

I'm trying to find time to pull down the 224" V8 from my '55 E12. It had some 3,000 RPM highway miles on the OEM seats and valves, so I'll be interested to see the recession on those.

FWIW, recently I saw a photo of a motorcycle head with hard seats. The valve face was completely worn away until the outside edge of the valve was seating down inside the hard seat. Engine still ran fine.

jack vines

[Commander Eddie]

Joe,
Thanks for sharing this. I too am putting a lot of miles on my '61 Champ with a 259 V8. About 1,000 miles per month. With this much daily use should I have my valves adjusted more often? How far should I be going between adjustments?

[Mike Van Veghten]

Joe -

I've found it depends or your (my) driving.
That is, if most of your driving is around town, and with short trips on the freeway, my adjustment intereval is more like 16/18,000 miles.
If I do more high speed freeway driving, the adj. intereval is more in with 14/15,000 miles.

If you think about it...this makes sense. Around town, things stay cooler, the valves don't pound as hard (rpm), as long as they would out on the freeway, at 3200/3500 rpm for long distances.

I like to keep an eye on my valve adjustment, just for this reason...being this is my daily driver.

And I also adjust them to the cold specs. of .027" int. / .029" exh.

Mike

[SN-60]

Joe -

I've found it depends or your (my) driving.
That is, if most of your driving is around town, and with short trips on the freeway, my adjustment intereval is more like 16/18,000 miles.
If I do more high speed freeway driving, the adj. intereval is more in with 14/15,000 miles.

If you think about it...this makes sense. Around town, things stay cooler, the valves don't pound as hard (rpm), as long as they would out on the freeway, at 3200/3500 rpm for long distances.

I like to keep an eye on my valve adjustment, just for this reason...being this is my daily driver.

And I also adjust them to the cold specs. of .027" int. / .029" exh.

Mike

You must like to listen to valve 'clatter'....adjust both to .026 cold and You'll be good to go!

[JoeHall]

Joe,
Thanks for sharing this. I too am putting a lot of miles on my '61 Champ with a 259 V8. About 1,000 miles per month. With this much daily use should I have my valves adjusted more often? How far should I be going between adjustments?

Hi Ed,
I'd say, if yours are hardened exhaust seats, and you set them on the loose side (.027" and ..029") figure on about 15,000 miles. If running OEM type seats figure around 10,000 miles. Those are good, safe intervals. Like I said above, your motor will also let you know if they are about closed up, with a rocking idle. But of course that's also a good way to burn out a valve if not attended to promptly.

Glad to hear someone else out there is putting some miles on their Stude

[JoeHall]

Hi, Joe,

As always, you can be relied upon to produce factual data. You also put more miles on your cars than most anyone. The 16,347 in a relatively short time span is rare among Studes today. Losing .013" on the exhausts is huge, much more than I'd have expected with hard seats.

I'm trying to find time to pull down the 224" V8 from my '55 E12. It had some 3,000 RPM highway miles on the OEM seats and valves, so I'll be interested to see the recession on those.

FWIW, recently I saw a photo of a motorcycle head with hard seats. The valve face was completely worn away until the outside edge of the valve was seating down inside the hard seat. Engine still ran fine.

jack vines

Hi Jack,
This motor's exhaust valve recession rate is about same as I have experienced with other hardened seats. The OEM seats are about twice as bad. Of course IIRC the Shop Manual says adjust them every 10,000, but I am just too lazy to do that. If only the exhausts receded at the rate the intakes do, it would be easy to go 50,000 miles between adjustments. That would be nice, but unfortunately it ain't so.

[JoeHall]

Joe -

I've found it depends or your (my) driving.
That is, if most of your driving is around town, and with short trips on the freeway, my adjustment intereval is more like 16/18,000 miles.
If I do more high speed freeway driving, the adj. intereval is more in with 14/15,000 miles.

If you think about it...this makes sense. Around town, things stay cooler, the valves don't pound as hard (rpm), as long as they would out on the freeway, at 3200/3500 rpm for long distances.

I like to keep an eye on my valve adjustment, just for this reason...being this is my daily driver.

And I also adjust them to the cold specs. of .027" int. / .029" exh.

Mike

Hi Mike,
I prefer tall gears and overdrive, so my motors live at around 2000-2500 RPM, except when winding up to shift.

I have learned to squeeze as many miles out of a valve adjustment as possible. It been many years since I have, but would never again have a set of heads done and install OEM exhaust seats, and that helps a lot. But also setting them a little on the loose side does too. Sounds like we are both from the same school in that sense

[StudeRich]

When you do this clickity Clack thing guys (loose Valves), how long do the Rocker Arm surfaces last?

It is interesting, Performance Cammed Studes. usually run at .014 to .016 driven hard, and no problems.

[Mike Van Veghten]

Rich -

They last just fine...why ? The stem tips checkout just fine also.
I've seen better performance...even with the stock cam, adjusted slightly loose rather thAn slightly tight. But that's just me...!

You apparently aren't aware of the early Corvette, Z-28 cams that were adjusted to .030"/.030" (hence the term...30/30 cam).

Mike

[PackardV8]

When you do this clickity Clack thing guys (loose Valves), how long do the Rocker Arm surfaces last?

It is interesting, Performance Cammed Studes. usually run at .014 to .016 driven hard, and no problems.

The clearance ramps are designed into each cam differently. There's no magic number. Some of the Isky copies for Stude performance cams run at the .015" you mention. Then there's the early Corvette solid lifter cam, the famous Duntov 30-30 was so named because it runs with .030" lash. Some "close-lash" special application cams run with .001"-003" lash.

jack vins

[studebaker-R2-4-me]

I'm installing new valve springs this weekend in my R2 in preparation for the PSMCDR next weekend. With that I will be removing the rocker arm assembly and filling the cylinder with air to keep the valves from falling into the cylinder. When I complete the valve spring swap out I will probably need to re-adjust the valves. My engine builder suggested .025 clearance cold, adjusting each cylinder's valve independently following the cam lobe profile. His system of adjustment is, when the intake valve just closes adjust the exhaust valve for that cylinder. Likewise when the exhaust valve just opens adjust the intake valve for clearance. Using this system of adjustment allows precise measurement from the cam, allowing maximum lift and performance.

Hopefully my time slip from the track will tell the tale of performance.

Allen

[JoeHall]

When you do this clickity Clack thing guys (loose Valves), how long do the Rocker Arm surfaces last?

It is interesting, Performance Cammed Studes. usually run at .014 to .016 driven hard, and no problems.

No clickity clack from the extra .004 to .005". Never had a problem with rocker arms, or anything else. Thinking out of the box is not for the squeamish or faint at heart. You can't go wrong by just going with the Shop Manual, and that may be best for you