Squeaky/tapping noise on #8 cylinder

[geezer#99]

Originally Posted by Mrturner1

I didn't change the springs at all during break in, I just assembled the heads and broke it in that way.

During the cam break-in, I got about 10 minutes in at 3200 rpm and a belt broke. So the next day I got a new belt and gave it 20 more minutes. I thought no big deal, but it's my first so I could be wrong.

10 minutes was good but 3200 rpm with stiff springs on a fresh cam is a killer!!

[Mrturner1]

Originally Posted by geezer#99

10 minutes was good but 3200 rpm with stiff springs on a fresh cam is a killer!!

The instructions from Comp were to give it 30 minutes with RPM's varied from 3000 to 3500, and to adjust the rpm every 5 or so minutes in 200 rpm increments. I just went with what they said to do

[Mrturner1]

Ok, so I need to determine the cause of this and I'll have some time tomarrow to pull it apart further. I haven't decided yet how far I'm going to pull it apart just yet.

I could get two new rockers from PRW and buy a set of hardened pushrods, then install all and adjust the valve lash again but a bit looser this time, 1/2 to 3/4 turn after zero lash. This would be the cheapest route as far as short term, but if I'm wrong there will be more damage later and it could be way worse next time.

Option 2 is pull the intake manifold off, check all the lifters and inspect cam for wear (although I don't really know what to look for on the cam) If the cam is flattening or has some damage due to the wrong break-in procedure (followed Comps instructions but who knows) then I replace the cam, check the lifters and install new pushrods and rocker arms. I'm out about 150 bucks for the cam, then there's gaskets and pushrods, ect ect

Option 3 I start over to be sure there's no metal peices floating around in the engine somewhere, and at that point I'm not going to put it back in again until I've gone through the short block and replaced pistons, rings, bearings, and have a solid bottom end that will hold up for years and years of fun and big smokey burnouts

It's hard to believe this is THAT bad but I'm relatively new at this so I could definetly be wrong.

[kwmech]

I've been building engines for over 40 years now. I recently rebuilt a 454 and put it in my 68, replacing the 396. Les than 1000 miles I had just about the exact same thing happen to me. #5 and 7 intake push rods did the same thing. These were brand new Crane parts. 3/8'' push rods (not the 5/16). I also had to replace the lifters. Did not do any damage to the roller tip rockers though. I still have no idea what went wrong or why. Good oil with the correct additives and everything. I adjusted the valves to zero lash plus 1/2 turn engine hot while running.

[Mrturner1]

Originally Posted by kwmech

I've been building engines for over 40 years now. I recently rebuilt a 454 and put it in my 68, replacing the 396. Les than 1000 miles I had just about the exact same thing happen to me. #5 and 7 intake push rods did the same thing. These were brand new Crane parts. 3/8'' push rods (not the 5/16). I also had to replace the lifters. Did not do any damage to the roller tip rockers though. I still have no idea what went wrong or why. Good oil with the correct additives and everything. I adjusted the valves to zero lash plus 1/2 turn engine hot while running.

You can adjust the lash while it's running? Is the motor that happened to back in and running fine now?

[Chknlyps2]

Originally Posted by Mrturner1

You can adjust the lash while it's running?

Yes, here is a video. https://www.youtube.com/watch?v=CEV3Yz0kpDY

I always cut a strip of cardboard the length of the valve cover and a couple 3 inches high and slipped it between the lower side of the springs and the lip around the head to catch any oil coming off the rockers so it doesn't drip down on the exhaust.

[Grumpy old man]

Oh, The need for speed raises its ugly head again . What grade pushrods are those , stock? Don't fall into all the horror stories just yet but dump that oil and cut the filter before you decide on any other fix . If its showing ANY metal you may as well just stop and really get a good idea of what happened and why . Can you save it ? MAYBE , it all depends on how much metal you find and how long you ran it that way ( I picture the hood up and you blipping the throttle thinking what is that noise ? ) don't spend a dime on it until you assess the extent of the damage . You'll only be delaying the inevitatable !
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[Grumpy old man]

I always adjust the valves with the engine running its just how it was done back in the day . And just because everything is new and running doesn't mean after a few hours of running that it's ready for the tire frying to begin ! I'm a firm believer in breaking in an engine I want to live for more than a couple passes down the track . The need for speed is expensive $$$$$ and $$$ . If you do find metal I'd slap it back together and use it up while looking for a replacement crate drop in roller engine . With a warranty ! I didn't like you dumping money into a repaired cracked block from the beginning !
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[Grumpy old man]

I just have to say these old stock engines are a whole different animal compared to today's replacement engines and if we looked at a used truck back in the 70's with more than 50,000 mile we would pass on it ! At 100,000 miles they where considered used up junk ! Today 100,000 miles is nothing . I still get a real kick out of firing up a bone stock l6 with its old points dist and single belt manual steering / brakes and good ol 3 on the tree , try it some time if you get the chance and you'll understand why us old guys still like them that way ! Some of the classyist trucks out there are bone stock !
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[kwmech]

Originally Posted by Mrturner1

You can adjust the lash while it's running? Is the motor that happened to back in and running fine now?

I always set the valves initially to break in the cam, then readjust afterwards. And yes I just went to the NAPA store in town and got 2 lifters and 2 push rods, dropped them in and adjusted. Been driving it for 2 weeks now, nice and quiet

[davepl]

MRTurner has likely not seen the procedure, but yes, you can set lash while running. It's messy and ugly, and better if you have special oil clips and a pair of valve covers with the tops cut off.

Basically you do it by loosening it until it rattles, tightening it until its quiet (zero lash) and then your 1/4 to 3/4 after that.

Grumpy is probably right about getting the filter cut to know just how much is in your engine. But if you're not adding any parts beyond a pair of pushrods and rockers, might be worth the chance to just run it. But don't put any money into it until you know!

Remember, this is the hobby we chose :-)

[Mrturner1]

Originally Posted by kwmech

I always set the valves initially to break in the cam, then readjust afterwards. And yes I just went to the NAPA store in town and got 2 lifters and 2 push rods, dropped them in and adjusted. Been driving it for 2 weeks now, nice and quiet

That's good to hear, I'm hopin that mine is a quick fix too. Since I had no damage on the lifter side of the pushrod is it possible I don't have to pull the intake manifold and replace those?

Man a big block would be awesome, that's on my list of "someday"s

[Mrturner1]

I'm okay with making repairs and if need be, puttin a little more money into it. But one thing I would hate is to repair it and run it again only to have the same thing happen IF ITS DUE TO THE CAM BEING FLAT OR BROKE IN WRONG. So, is there a way to know if my cam is trashed for sure? It would really confuse me if it is the cam though, because I followed the break-in procedure from Comp, and all the guys on here. The directions were simple for the initial break-in. It was said earlier to break in the cam and then re-adjust lash again, well being my first time I could've adjusted it wrong and I never re-adjusted after break in so that seems more likely to me.

I'm gonna go drain the oil and cut that filter to check out how much metal is in there

Thanks for all the help and input guys! Cross your fingers

Matt

[Grumpy old man]

Before you go adjusting the valves while it's running understand it needs to be done SLOWLY !!! Once you have it back together and running with 1 valve cover off and a shop rag laying over the top of the rockers to try to control some of the splattering oil , ( don't catch it on fire) SLOWLY really slowly loosen the rocker until it clicks and then SLOWLY tighten it back to 1/2-3/4 turn down . Keyword here is SLOWLY or you take the chance of bending the valve !
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[snipescastle2]

Yeah, stiff springs don't like stock pushrods for sure. I'm surprised the roller rocker arm socket wasn't more galled than it was.hope you get it fixed at minimal cost....
Ben

[hamjet]

The tips of the pushrods wear just like anything else with high mileage. at the tip it could have worn very thin and with the high pressure springs along with a different mating surface,( new rockers) it probably failed for these reasons. I'd change them all.

[Mrturner1]

Originally Posted by hamjet

The tips of the pushrods wear just like anything else with high mileage. at the tip it could have worn very thin and with the high pressure springs along with a different mating surface,( new rockers) it probably failed for these reasons. I'd change them all.

Ok I looked at some pushrods today. Comp has a set of CS High Energy pushrods for about 60 bucks. Not sure if those are hardened but I'd like to find some that are.

My question is, how do I get a set that's exactly the right length? Do I measure one of mine (one of the good ones) and what do I measure them with? I think I'm going to replace all the rocker arms with Comp 1.6 ratio arms. My valve springs are rated to .525" max lift, and with 1.6's I should be around .512" if my current setup is .480" with 1.5's

One thing I was disappointed about with this cam grind was that the intake and exhaust lift are exactly the same. From my reading I've learned that these SBC motors like a little MORE on the exhaust side (please correct of I'm wrong) so this could be an opportunity to change it up for the better

[Mrturner1]

Never mind the 1.6 rockers, my springs are only good to .490" lift

[hamjet]

I'm not sure with roller rockers, but as far as I remember there is only one size STOCK pushrod length for SBC. I wouldn't change rocker arm ratio, it will put more stress on the pushrods and cam lobes. plus you're getting into a different set of possible problems, (piston / valve interference)

[hugger6933]

Matt, call 1-800-CAM -HELP. That is the Comp cams tech hotline. Tell them what you have and they can spit out a Comp part number for the part you need. There are two different SBC pushrods but the shorter ones are off the later roller motors and has no bearing on/in this case. I think that number is a 24 hour deal but I may be wrong and being in Memphis TN, [75 miles from me] those guys are gearing up to go to Super Chevy this weekend. It is kinda a big deal around here. Comp normally has a trailer or two and sometimes even a couple tents at the race/show

[davepl]

Originally Posted by Grumpy old man

1 valve cover off and a shop rag laying over the top of the rockers

...never thought of that. I used those little clips, which weren't bad, but I've been shot in the eye with oil too. The simple things... shop rag!