Sudden Loud knocking

[bobbyn362]

i knew it was in the top of the motor.

[S.J.SLEEPER]

Originally Posted by BonzoHansen

can he use a bore scope to look?

Yes, thats why I put 3) in there.

i'd still rather do lifters then a whole bottom end!

Absolutely!!!

Originally Posted by LTs1ow

More importantly, if this is not the first time this has happened, you should figure out what in your valvetrain is causing your rocker to be the weak link.

Too much spring pressure, or to much pushrod travel etc etc

Ive seen this happen with .550" springs and all way to .675"+ springs.
The problem isnt the spring pressure, its the weak area of aluminum that the hardened seat for pushrod sits in. That area normally is "beefed up" to withstand the pressures applied to it, but in the Ls case rockers, these aftermarket aluminum ones run a thinner area there to allow clearance of stock valve covers and such. Any taller and the pushrod side of the rocker will hit inside of valve cover and scuff against the gasket rail of the head.

[qwikz28]

Yikes. I have no idea how to check a lifter. I guess this thread will have to go for a little longer. I suppose pulling a head is way better than replacing a shortblock, so I'll be grateful.

When I lost the stock rockers, the problem wasn't the rockers, but rather a hole in the head. I dont think there is any problems in my valve train besides this one rocker that failed. I'll likely send the stock rockers for a trunion upgrade before installing them as I tend to spin this motor pretty high.

I'll check the intake next. The current one is a ported stocker ls6. I actually didnt notice whether the piece that broke off of the rocker is in there either. Looks like my work is only just beginning. Ill continue work on her next week, i feel much better now that I know what is wrong with the car.

Thanks for all the help this week fellas. I really am very grateful.

[V]

Jake, just let me know when ur around, Either I can drop them off or if you're in the area u can pick them up. I have 2 full sets and no ls1 build plans in the works so they are just taking up room. I really don't need any money for them.

On an added note,
When i built my ss motor, i took the brand new GM rockers from the LS6 and sent them out to Harland Sharp to get the bearings swapped out for trunion bearings. I then had the benefits of stock rockers and the knowing that id never explode needle bearings inside my engine. Held up fine for 500 flywheel hp.

[S.J.SLEEPER]

Jake, when i get a few minutes, I'll find a stock lifter laying around and post up pics of what it should and shouldn't look like. Ill also give you a shot of how to inspect for it.

[MyFirstZ]

Might wanna look around for that chunk of metal also. Hopefully it stayed in the head

Hope that is still the only issue, again any help needed just let me know

[1984camaroz28]

Originally Posted by S.J.SLEEPER

DO NOT get all excited yet Jake.
1) I can almost guarantee that you will need to replace intake or atleast epoxy & grind it due to the backfiring through the intake
2) you will need to pull the head off,....sorry to tell you this, but very common for when rocker breaks, the pushrod beats around on top of lifter and pops out the retaining clip, which then releases thelifter body & spring from its case.
3) OR... you can use your 20/20 vision and a flashlight to look down in hole to confirm clip is completely seated, but MAKE SURE 110% that it is.
Cuz if you don't, the lifter will evebtually come dissasembled down the road and circulate into the rest of your engine. And then you will no longer be getting off easy.

p.s. make sure you find the rest of the rocker (hardened seat part)

agreed

[qwikz28]

Thanks Curt. I have installed lifters on the car before when I originally did the heads and cam, so I am moderately familiar. I'll see what I can do to peek inside, but its the number 6 cylinder so it will be tough to wedge my massive head in there to see the lifter.

Paul- will you be around at all tomorrow? And I think Comp cams does the same upgrade now as Harland sharp. I was looking at it earlier today

[V]

Yea ill be around at some point tomorrow, I just know I'm helping my friend help his sis-in-law move for a few hours, then im going out at night. but im not busy the whole day.

[qwikz28]

I have to pick up my sister from JFK at130. Can I swing by late afternoon?

[V]

Originally Posted by qwikz28

I have to pick up my sister from JFK at130. Can I swing by late afternoon?

yea, i should be home and free by then. ill PM u my cell in case you don't have it, just call me a little prior to make sure ill be home

[S.J.SLEEPER]

autozone rents tools, you rent it, your return it, and get your $ back, so it costs nothing.

Autozone may have a borescope (like Bonzo mentioned) you can rent. That would do the trick.

If all is good, just make sure you get that pusshrod seat out of the motor. You can stick a magnet in pan through drain plug hole, and use a heavy duty magnet to drag across pan towards hole to get it. That would be awesome if you can dig it out of the motor without having to pull motor out...
Good Luck bro, and if you need anything give me a shout.

[S.J.SLEEPER]

another thing....
how old are the yella terra rockers? I know that Scorpion & YT both had problems in their first designs. Call YT and they will replace the set you have w/ a new set. Then sell that set online to help pay for the trunion upgrade w/comp. If you need a "reciept" I can hook ya up so they'll take them back.
FYI: Harland Sharp & Mast both make a nice inexpensive aftermarket set of rockers that haven't had any issues

[qwikz28]

I got the rockers back in 07 or 08, and I just looked and couldn't find a receipt. I will call them, no doubt, this week and raise hell about the rocker that broke with low miles on it.

I don't see a borescope on Autozone to rent, but they aren't expensive so I'll just order one off Amazon and I should have it by Wednesday when I'm off from school and have time to continue diagnosis.

The rockers are aluminum, so I likely won't be able to catch it with the magnet. If I can't find that broken piece, I may be having to drop the pan. I just hope I can do that with the motor still in the car.

[qwikz28]

Also looks like I'm going to need 7.350" pushrods with this cam. Not sure how I would check if this is correct, but I found some old threads from TTP and it appears they used 7.350" pushrods for cam upgrades: http://ls1tech.com/forums/4316179-post2.html

[sweetbmxrider]

Pushrod length checker and a sharpie. Google gogogo!

[MyFirstZ]

The subframe is to close you can only drop it inches.
I should of offered but I forgot.... could of borrowed one the guys at work

[qwikz28]

Originally Posted by sweetbmxrider

Pushrod length checker and a sharpie. Google gogogo!

Got it. Found a good article. I used to own a pushrod length checker, but lost it. I didn't know how to use it anyway and ended up putting pushrods in the car that were too short. Took it to Josh and picked up about 20whp. True story.

Originally Posted by MyFirstZ

The subframe is to close you can only drop it inches.
I should of offered but I forgot.... could of borrowed one the guys at work

I believe there is a way to get the pan off by unbolting the motor mounts and some other things while lifting the motor with an engine hoist a few inches with the frame of the car on stands. That should give enough clearance to get the pan out. I still have to pop the covers back off and look for the broken piece again. I may not need to drop the pan at all.

As for the help at the shop, much appreciated. I'll let you know if I need a hand. You live walking distance from me!

[MyFirstZ]

Ha yes I do....
I was going to suggest the liftng off the motor mounts but wasn't sure how far you were going to go. Since you mentioned limited room to.

[NastyEllEssWon]

on a side note after you get this all back together....all this money youve spent on the car....lose the fram

[sweetbmxrider]

Looks penzoil.

[LTb1ow]

And clean it, that thing is dirtier than my LT1...

[BonzoHansen]

Originally Posted by sweetbmxrider

Looks penzoil.

and a fram. nice.



edity: whoops, that filter looked orange on my phone, and I thought it was nasty's car lol

[S.J.SLEEPER]

Originally Posted by LTs1ow

And clean it, that thing is dirtier than my LT1...

still lighter & faster than your Ltnone...

[S.J.SLEEPER]

Jake,
There is a preload tolerance amount for the lifters.They are hydraulic so you don't have to spot on.measure w/a dial indicator from time pushrod just touches rocker to completely bolted down. you want 50 -100 thousands preload.
Example: with 7.350 pushrods, if you have 150 thousands preload, you want to go with 7.275 or max of 7.300 length rods.

Depending on head milling and decking of block, head gasket thickness, you will need anywhere between
7.300 and 7.400. I have yet to build one that needed under 7.300.
most are 7.350-7.400.