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

[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 [img]<<GRAEMLIN_URL>>/bs.gif[/img]

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!