Sure gets annoying when.....................

[napa68]

You gotta revisit what you have done already. Not even 500 miles and I have a valve train issue that shows up after 2000 rpm on the left bank. I would say I have a cam bearing issue. Out it comes! Just kind sucks.

Off to the machine shop and regroup before something gets wrecked

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[Tracker1]

I feel for ya. That sucks. <<GRAEMLIN_URL>>/no.gif

[RST]

Oh man what a bummer, sorry to hear, hang in there, you will be back on the road in no time.

[Postsedan]

Better now, than more damage later - taken with a grain of salt.

Dan

[Mr. Chevy]

I KNOW EXACTLY what you are going through very well unfortunately. I had a major issue with my 396 69 Chevelle Motor and it had to come out after the total rebuild and instillation. Really sucks!! Only positive is that you can have these motors in and out of the engine bay relatively quickly. Not like todays cars...

Good Luck!!

Rich

[Day2_69Z]

Hmmmm, a cam bearing noise on the Left Bank ??? Cam bearings are fixed to the bore journal ,centered on the cam ...... Both Banks would have a noise.
Doesn't sound right to me either....

You don't think its a bad Rocker Arm, pivot ball, lock nut or an issue with a Rocker arm Stud ?
A too long or too short pushrod ?
Just my thoughts. .. somewhere on the Left bank you may want to check.

[napa68]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Day2_69Z</div><div class="ubbcode-body">Hmmmm, a cam bearing noise on the Left Bank ??? Cam bearings are fixed to the bore journal ,centered on the cam ...... Both Banks would have a noise.
Doesn't sound right to me either....

You don't think its a bad Rocker Arm, pivot ball, lock nut or an issue with a Rocker arm Stud ?
A too long or too short pushrod ?
Just my thoughts. .. somewhere on the Left bank you may want to check.
</div></div>

Right side is a problem too. #5 more than anything. Collapses over 2000 rpm when the oil temp comes up. Go back to idle, pumps back up. Changed out all of the lifters (cam and lifters looked good), the same problem. Oil pressure is well north of 70lbs cold (idle) and is at 50lbs at a hot idle (stock pump and spring) Checked valve springs...............they were new and good. Gotta pull it apart before something gets wrecked.

[earntaz]

Did you have the engine running before rebuild -- or did you obtain the block from another source? The reason I say this is a friend of mine had the same issue and found there were oil restriction devices in the cam galleys. The block was used for racing and had them installed to control how much oil went to the lifters. TAZ

[camarojoe]

I just went through something similar, but &quot;only&quot; had to remove the heads,(and intake of course) leaving the motor in the car. Initially thought I had a collapsed lifter, but ended up being a badly worn valve guide. Took off both heads and had them all replaced to be safe. Still not sure how or why there was so much wear with so few miles, but in any case... one more thing to look for.

[napa68]

The engine (block, heads, intake, etc) are all original to the car. It was pulled apart for a rebuild. Funny thing is, it was on the dyno and worked fine. This problem reared it's head after 200 miles and has proceeded to get worse (now about 500 miles) <<GRAEMLIN_URL>>/bs.gif

My suspicion about cam bearings is further supported by the huge oil pressure.

[67 Nova Boy]

A reply from Hilborn specialist.. Andrew Star on just what info is posted.

Nice car, sucky issue.

My immediate observation was that the rockers weren't laying on the valves right, possibly the push rods are too long or the angle of the picture tells a different story. But that isn't his problem nor is it his cam bearings.

He didn't mention if he had a hydraulic or solid cam. Since the lobes aren't flat and if he has a hydraulic cam then it sounds like he has a suction side issue on the oil pump. Namely a cracked pick-up or loose/incorrectly installed pick-up. When the oil is hot the crack starts to suck air allowing the air to get into the hydraulic tappets causing the lifters to bleed down and become noisy. A simple test is to get a high quality oil pressure gauge, such as one from Snap-on, and watch the needle as you rev the engine. If it vibrates back and forth wildly then it's sucking air. I've fixed numerous noisy tappets by replacing the pick-up tube. I ALWAYS tig the pickup on after installing it with the correct tool. This ensures that it will never come out or leak. Cheap insurance for such a sweet build. This also explains why the lifter swap had no effect, which is typical first repair for this issue.

Dave
67 Nova Boy

[earntaz]

Sure hope the cam bearing(s) haven't rotated in the block ... UGH!@#$

[napa68]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 67 Nova Boy</div><div class="ubbcode-body">A reply from Hilborn specialist.. Andrew Star on just what info is posted.

Nice car, sucky issue.

My immediate observation was that the rockers weren't laying on the valves right, possibly the push rods are too long or the angle of the picture tells a different story. But that isn't his problem nor is it his cam bearings.

He didn't mention if he had a hydraulic or solid cam. Since the lobes aren't flat and if he has a hydraulic cam then it sounds like he has a suction side issue on the oil pump. Namely a cracked pick-up or loose/incorrectly installed pick-up. When the oil is hot the crack starts to suck air allowing the air to get into the hydraulic tappets causing the lifters to bleed down and become noisy. A simple test is to get a high quality oil pressure gauge, such as one from Snap-on, and watch the needle as you rev the engine. If it vibrates back and forth wildly then it's sucking air. I've fixed numerous noisy tappets by replacing the pick-up tube. I ALWAYS tig the pickup on after installing it with the correct tool. This ensures that it will never come out or leak. Cheap insurance for such a sweet build. This also explains why the lifter swap had no effect, which is typical first repair for this issue.

Dave
67 Nova Boy </div></div>

Dave,

Thanks for the post. This was suggested to me already. Since the engine builder is primarily a race car guy, he installed a high pressure / high volume pump (which was welded together). It did it then. I had since changed the pump to a stock unit and the problem still exists. Oil pressure does not fluctuate according to the stock gauge. FWIW, it is a hydraulic cam

I do appreciate you guys taking the time to post some of your experiences to minimize my grief!

Tim

[napa68]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: earntaz</div><div class="ubbcode-body">Sure hope the cam bearing(s) haven't rotated in the block ... UGH!@#$ </div></div>

Me too!

[SuperNovaSS]

This isn't an early 67 962 block is it? That block requires a grooved rear most cam and matching bearing for valve train oiling as well as the correct dizzy.

Jason

[SupremeDeluxe]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: napa68</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Day2_69Z</div><div class="ubbcode-body">Hmmmm, a cam bearing noise on the Left Bank ??? Cam bearings are fixed to the bore journal ,centered on the cam ...... Both Banks would have a noise.
Doesn't sound right to me either....

You don't think its a bad Rocker Arm, pivot ball, lock nut or an issue with a Rocker arm Stud ?
A too long or too short pushrod ?
Just my thoughts. .. somewhere on the Left bank you may want to check.
</div></div>

Right side is a problem too. #5 more than anything. Collapses over 2000 rpm when the oil temp comes up. Go back to idle, pumps back up. Changed out all of the lifters (cam and lifters looked good), the same problem. Oil pressure is well north of 70lbs cold (idle) and is at 50lbs at a hot idle (stock pump and spring) Checked valve springs...............they were new and good. Gotta pull it apart before something gets wrecked. </div></div>

FWIW, I had a HV/HP pump installed in my 67 L-68, installed by engine builder before I got the car, and the oil pressure was exactly what you describe. It would never dive below the 45 psi hash on the gauge at hot idle, and by 2000 RPM the gauge was always pegged. It never caused me any issues, and I drove it that way for thousands of miles.

Feel your pain on the R&amp;R. I had the trans out of mine three times this summer trying to correct internal problems, and it looks like it may be coming out for a 4th.

[napa68]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SuperNovaSS</div><div class="ubbcode-body">This isn't an early 67 962 block is it? That block requires a grooved rear most cam and matching bearing for valve train oiling as well as the correct dizzy.

Jason </div></div>

Yes it is.................and that is what my suspicion is. The car was built early October of 66. If memory serves me correct, the block is July or August of 66.

[earntaz]

Early block? -- Jason is spot on ... needs a groove in back cam journal and matching bearing. TAZ

[napa68]

Just to follow up...............we found the culprit! The cam and cam bearings were correct.

The problem.....................valve guides were too tight on all of the exhaust valves. The new guides were galled up. Even so bad...............the valve hit the piston on the #2 cylinder.

Uhhhhhhhhg <<GRAEMLIN_URL>>/bs.gif

At least we found it and can move on from here!

Tim

[camarojoe]

I guessed a valve guide problem... mine were too lose, yours were too tight. Either way... bad news! Glad you got it sorted out!

[napa68]

Back from the machine shop. 433 hp @ 5700. 430 tq @ 3700

Going back together! Sure seems like it takes a lot of work to get back to where you started.

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[Xplantdad]

Beautiful!

[RPOLS3]

Nice!

[BJCHEV396]

X2!!!

[VintageMusclecar]

Was that with headers or the Corvette manifolds, and what cam did you use?

[green crv]

Really nice corvette, love the color. Had to laugh when I saw it was green, I've been told twice about my Chevelle being forest green, one older guy and a 12 year old girl said nice car, but wished it was red, and asked why I would buy a green car? Glad your problem was found before it came apart at 6000 rpm, on a cruise, or a ways from home. Steve. <<GRAEMLIN_URL>>/3gears.gif

[napa68]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: VintageMusclecar</div><div class="ubbcode-body">Was that with headers or the Corvette manifolds, and what cam did you use? </div></div>

With headers. There is a larger cam in it, but has the same manners and vacuum readings. I'd have to go back and look up the specs. I reused the cam. Certainly, it would not make that kind of power with a 9:1 CR and the stock cam.

Tim

[TimG]

I owned '67 #2867 that had a 400 HP built the same day. The assembly stamp is identical, same 0 and the other characters are identical. If you laid your assembly stamp directly over mine, they would match exactly.........