Id this odd engine noise. old problem time to solve it

[Redline novdog]

if there are pushrod issues it would be very visable with a valve cover removal!

[mtdave2]

great info guys thanks.

everyplace i have looked shows .475 max lift. not sure where they get the .420?

http://www.jegs.com/p/Chevrolet-Perf...49896/10002/-1

http://www.jegs.com/i/Chevrolet-Perf...58060/10002/-1

[mtdave2]

new everything was used, I want to say eagle brand pistons, not sure.

Problem there from day one, reputable shop did the work, (like 6 years ago now, and i live in a different state)

The crank is NOT hitting the pan, nor the lifters the cover. sound is defiantly from the top of the motor.

viscosity? 10/30. I would think if it was too thin, it would be better when cold? it is worse.

[mattfranklin]

Yes, higher, but with modifications.
I read the 0.420" limit was for the unmodified guides.

But I'll read your links, too -- thanks for sharing those.

Originally Posted by mtdave2

great info guys thanks.

everyplace i have looked shows .475 max lift. not sure where they get the .420?

http://www.jegs.com/p/Chevrolet-Perf...49896/10002/-1

http://www.jegs.com/i/Chevrolet-Perf...58060/10002/-1

[mtdave2]

all i am going by is the listed max valve lift listed on the specs for the heads... I am really out of my area when it comes the heads and valves, so ill defer to the experts.

[mattfranklin]

I took the CarCraft and SuperChevy articles as Gospel, but you're right, there are differences in opinion.

I'm going to have backtrack and say I don't know because I have not personally worked with those heads myself.

This comes from the official GM/Chevy Power Catalog:

12558060 Cast-iron Vortec Cylinder Head Assembly
• Completely assembled with 1.940"/1.500" valves
• Uses bare head 12529093
• 64cc combustion chamber
• Straight spark plugs
• No heat risers
• Requires Vortec-specific intake manifold
• Camshafts with more than 0.475" lift require machining valve guide
bosses and checking valve seal to valve spring retainer clearance
• Can be machined for 2.020"/1.600" valves
• Rocker arm studs can be pinned or drilled and tapped to 3/8"
• Valve spring seat diameter is 1.280"
• Casting number 10239906 or 12558062
This head is assembled with the following components:
10241743 Intake Valves 10241744 Valve Spring Retainer
12550909 Exhaust Valves 10212810 Intake Seals
10212811 Valve Springs 12564852 Exhaust Seals
24503856 Valve Locks

So maybe you're ok. I don't know now. I'd hate to send you down the wrong path and do that disassembly and machining for nothing and still have the noise. But it still kind of stands out to me that CarCraft recommended the machine work. They are usually a pretty reliable source.

Anyone have firsthand experience with these heads?

Originally Posted by mtdave2

all i am going by is the listed max valve lift listed on the specs for the heads... I am really out of my area when it comes the heads and valves, so ill defer to the experts.

[mattfranklin]

Here's the CarCraft article:
http://www.hotrod.com/how-to/engine/...l-block-chevy/

I was mistaken. They are successfully running 0.431/0.451 lift cam. I was confusing it with the SuperChevy article. Sorry about that. I guess I was hoping for a quick easy fix for you.

[Captainfab]

I have run the Vortec heads with a cam that had valve lift of .462/.480. The only thing changed was upgraded to a set of Comp 981 springs. Retainer to seal clearance was checked and was good.

[mattfranklin]

The process of elimination continues...
What kind of rockers is this engine using?
Are they the guided rockers that use the top of the valve to keep themselves centered?
Or do they require guide plates?

[mtdave2]

http://www.summitracing.com/parts/SUM-G6935-16/
rockers

[Marshy]

Your on the right track regarding the valve stem seal clearance. I've researched the hell out of those heads before I started my 350 build this spring and can tell you that the clearance to the retainers should be checked if you have a cam with valve lift greater than 0.450. There is some variation from head to head and all the articles I've read but if you're going into that relm of valve lift the clearance needs to be checked. My heards had the guide boss lowered because my cam lift is .480/.489... I'm not certain he checked the clearance before machining them or if he remember how much they had before machining them at this point or I woukd ask. The rockers need to be self aligning if your not using a guide plate. Hope this helps.

[mattfranklin]

Looks like they are indeed self-aligning.

Originally Posted by mtdave2

http://www.summitracing.com/parts/SUM-G6935-16/
rockers

Here's an interesting summary of advice for these heads:
http://www.crankshaftcoalition.com/w..._cylinder_head

There is a discussion on opening up the push rod guide holes in the head, but that's only for 1.6 ratio rockers and yours are 1.5. Still grabbing at straws.

BTW, I saw an earlier discussion of your troubleshooting history with your engine:
http://67-72chevytrucks.com/vboard/s...d.php?t=511559


And just let me throw this out there -- probably not the issue you have -- but something I have seen...
My current project truck had a pretty bad clattering sound from the time I bought it that sounded a lot like valve-train and a little like rod noise. When I got apart I discovered that it had STANDARD rod bearings on 0.010 UNDER rod journals. Not sure how that could have even transpired except maybe a combination of an inexperienced assembler, a mix-up at the parts counter, and no double-checking with plasti-gauge. Mine sounded better when cold and with 15W40 oil. I'm currently in the middle of rebuilding mine.

[mtdave2]

I am loving all the input, thank you guys.

Ha! I forgot about that other thread! oh well, good to start fresh i guess.

I have the truck in the garage now, my plan is to sort a few other things out that i have been putting off, like doping that aux tank and rehabbing it, run all new steel fuel lines. I will have nice clean gas. Then, I will track down some wiring gremlins.

then i guess ill start fresh with this problem. verify timing, paint the push rods see if they are turning. ect.

I will solve this problem one way or another. whole new engine if i have to..

[toolboxchev]

Originally Posted by mtdave2

I am loving all the input, thank you guys.

Ha! I forgot about that other thread! oh well, good to start fresh i guess.

I have the truck in the garage now, my plan is to sort a few other things out that i have been putting off, like doping that aux tank and rehabbing it, run all new steel fuel lines. I will have nice clean gas. Then, I will track down some wiring gremlins.

then i guess ill start fresh with this problem. verify timing, paint the push rods see if they are turning. ect.

I will solve this problem one way or another. whole new engine if i have to..

Man I had that same noise with that Comp Cam and their lifters, yet still had power. HMMM????

I was on my 3rd oil change after rebuild when I dropped the oil out with the Lucas additive at about 1000 miles. I remember exactly that I went through the valve lash adjustment also doing exactly as Comps Techs recommended. I believe their method goes like this EOIC.

Exhaust Opening, then adjust the intake valve

Intake Closing , then adjust the exhaust valve

Start with the Number 1 cylinder and run to number 8.

Fresh Oil and no more problem. If you do not have threaded rocker studs, those press fit ones can work loose therefore changing the valve lash. Don't ask me how I learned that one.

Fresh Oil and the problem was gone 4 me. Comps tech service guys are top notch. They will walk you through exactly how they want their Cams valve lashed.

Call them, it cant hurt, and you most definitely learn something.

[Marshy]

Originally Posted by toolboxchev

Man I had that same noise with that Comp Cam and their lifters, yet still had power. HMMM????

I was on my 3rd oil change after rebuild when I dropped the oil out with the Lucas additive at about 1000 miles. I remember exactly that I went through the valve lash adjustment also doing exactly as Comps Techs recommended. I believe their method goes like this EOIC.

Exhaust Opening, then adjust the intake valve

Intake Closing , then adjust the exhaust valve

Start with the Number 1 cylinder and run to number 8.

Fresh Oil and no more problem. If you do not have threaded rocker studs, those press fit ones can work loose therefore changing the valve lash. Don't ask me how I learned that one.

Fresh Oil and the problem was gone 4 me. Comps tech service guys are top notch. They will walk you through exactly how they want their Cams valve lashed.

Call them, it cant hurt, and you most definitely learn something.

You are right about EOIC, its also on their web site.
http://www.compcams.com/v002/Pages/4...ableValveTrain

[mattfranklin]

Any progress?

[mtdave2]

not yet. I am rebuilding the fuel system, tanks and all. then im putting a new wiring harness in. after all that is done I will work on this issue. give me a few weeks!

[mattfranklin]

I know how that goes. I imagined that I'd have mine running over the break, but only got as far as torqueing in a new front cross member and cleaning and painting my engine block.

Keep us posted. It's an interesting problem to solve.

[mtdave2]

Well i did a complete leak down test, and compression test on the motor. Results are low of 5% leakage high of 9%. air coming out of the dipstick. Really don’t think that is out of line.

Compression 121-228. again, unremarkable results.

Only odd thing i found was all the spark plugs were gapped at 55, not 45. shrug.

[Ironangel]

If the build quality comes anywhere near the sound byte quality, the motor is either toast or a good running diesel in need of a turbo...Tear it down and spec everything paying special attention to the balanced rotating assembly and its individual parts. Forged piston slap, or the lack there of, in holes clearanced for hypereutectic cast aluminum pistons but got Forged pistons instead?...Open them pipes up and run it like a rented mule! Or disassemble it now and find where the missing pony's escaped? ~Ghostrider~

[cadillac_al]

I can't help because photocraps malware is too much for my old computer. Am I the only one still running an old computer? I think newer computers can just store the malware and keep working. Mine gets the blue screen of death just like win 98 days. photcrapbucket sucks.

[kwmech]

Years ago my father-in-law put an engine together when he was working for me. For some unknown reason he got the cam timing out 90*. It started right up and ran, sounded exactly like that, a diesel idling. Pull the timing cover.

[mtdave2]

Update. Timing marks are good. Did find a few things. .55 spark gap, vacuum leaks in carb butterfly shaft, and a bad harmonic balancer.

Threw another carb that I had on, runs a bit better, took off, inspected adjusted all the rockers and push rods, new ballancer, .45 plug gap. changed the oil. Used 2 cans of carb cleaner looking for more leaks. Re timed. Engine runs better, but still does not spin the tires.

Verified again I have around 4:11 rear gears, stock height tires. Thing runs great at 70, just as no low end. Ugh.

some video of the rockers. all looks normal to me. still hear a bit of tapping/knocking but my ear knows the sound I am trying to find.

https://www.youtube.com/watch?v=wPVGXDh0d_Q
https://www.youtube.com/watch?v=GffU_YD6Rac

[mattfranklin]

So, here's another comment on the valvetrain clearance issue. Hot Rod says it depends on manufacturing tolerances of the heads. Sometimes you can get away with more lift, sometimes not. That would explain all of our references and experiences.

Freiburger's comments on that issue start just a little after 6:00 on this video:
https://www.youtube.com/watch?v=Fbd33oEyCbU