Z06Vette.com - Corvette Z06 Forum - Broken Lifter

-X- · 10-01-2008, 08:48 PM

Started hearing a loud knocking sound yesterday about two miles from home, no check engine light, luckily I made it without breaking down. Had it towed to a shop today and the initial diagnosis is a broken rocker arm. Tomorrow it will be looked over fully.

If it is as such, what can I expect to pay (excluding labor) to have all rocker arms replaced? Any recommendations on potential replacements?

The Z's previous owner had a nitrous kit installed (which I had him remove). Is it reasonable to expect that there are other parts that might have been weakened as well due to nitrous kit? Any advice would be appreciated.

seamus2154 · 10-01-2008, 09:02 PM

Alot of guys have switched to Harlan sharp rockers and been happy. I haven't had any problems yet but the needle bearing failures in the rocker still plague the c6z also.

-X- · 10-01-2008, 10:13 PM

What about Jesel SS shaft rockers or Yella Terras?

Z1LE · 10-01-2008, 11:04 PM

Yella Terras seem to be a popular option w/ guys around here. The Jesel SS rockers are pretty decent for the money, we've used quite a few sets of these on bracket motors with good success. I would advise putting on new springs while you're at it. Chances are good that if the guy had spray on the motor he was ragging on the car. Step up to a 1.8 ratio as well.

-X- · 10-01-2008, 11:37 PM

Thanks, I was wondering if I can get away with the 1.8:1, seeing as the car has had the following installed/done by the previous owner:

GTP stage 2 + CNC ported and polished cylinder heads
Ferrea stainless steel intake/exhaust valves, 2.02"/1.57"
REV dual valve springs
Hardened steel valve spring cups and shims
Competition Cams hardened chrome moly pushrods
Five angle valve job
REV titanium valve spring retainers
DTE custom engineered billet steel hydraulic roller camshaft - .588/.588 228/228 112 LSA
Blueprinted and degreed valve train assembly
Ported and polished throttle body
Ported and gasket matched intake manifold

I'm probably going to go with the YT UltraLites, so the REV springs should be replaced anyway due to the lighter YT rocker tips, correct? Meaning, they won't need to be as firm as with the heavier stock or HS rockers, or am I way off in my reasoning on that?

Last C5 · 10-02-2008, 12:51 PM

Quote:

Originally Posted by -X-

Thanks, I was wondering if I can get away with the 1.8:1, seeing as the car has had the following installed/done by the previous owner:

GTP stage 2 + CNC ported and polished cylinder heads
Ferrea stainless steel intake/exhaust valves, 2.02"/1.57"
REV dual valve springs
Hardened steel valve spring cups and shims
Competition Cams hardened chrome moly pushrods
Five angle valve job
REV titanium valve spring retainers
DTE custom engineered billet steel hydraulic roller camshaft - .588/.588 228/228 112 LSA
Blueprinted and degreed valve train assembly
Ported and polished throttle body
Ported and gasket matched intake manifold

I'm probably going to go with the YT UltraLites, so the REV springs should be replaced anyway due to the lighter YT rocker tips, correct? Meaning, they won't need to be as firm as with the heavier stock or HS rockers, or am I way off in my reasoning on that?

The YT Ultralites are a good way to go, but the 1.8s will put you at a .622 lift which might not be to your advantage with those heads.

Terry S · 10-02-2008, 06:08 PM

I doubt if the nitrous had anything to do with the rocker problem. Probably just a part failure.

-X- · 10-02-2008, 06:55 PM

Guy at the shop said the rockers are fine, so they have to tear it down further and attempt to find where the expelled needle bearings came from. He's speculating they are cam bearings or from the lifters. I had him show me one of the bearings and it was ~5/8" long. His tech that was supposed to do the teardown had a personal emergency and had to leave before getting to it today.

I get the feeling it's going to be expensive, whatever it is. Good opportunity to put in the YT UL rockers (he recommended new retainers, everything else was fine in the valvetrain) and underdrive pulleys.

-X- · 10-02-2008, 07:00 PM

Quote:

Originally Posted by Last C5

The YT Ultralites are a good way to go, but the 1.8s will put you at a .622 lift which might not be to your advantage with those heads.

I figured it would be too much. What would need to be done in order to use 1.8s? Just curious.

PaulS · 10-02-2008, 07:19 PM

lifter, been there done that.... probably have a heavily scarred camshaft as well. I think the needle bearings just dump into the pan after the lifter valleys, I'm sure someone here will correct me if I'm wrong

I'd install Cadillac racing lifters at the least and Morel racing lifters if it were my motor.

Sounds like you will get to choose a new cam. Save the old cam for a lamp since they are hollow it's easy to make and save the rockers for door pulls on your cabinets:

-X- · 10-02-2008, 07:58 PM

Bigger cam? Hmmmm... I'll look for info on the Caddy and Morel lifters.

Z1LE · 10-02-2008, 09:45 PM

The needles are probably from the lifters as stated by PaulS. Find the flow numbers for the heads, and that will help to determine whether more lift will be beneficial. (I'm guessing yes). In order to run 1.8 rockers, the valvespring heights need to be checked to make sure you don't get into coil bind and interference with the guide. Assuming the same cam, there is no need to replace the springs if they have adequate seat and open pressures. Valve spring pressures have to do with weight of the valvetrain, rpm, and ramp speed on the cam. The faster the ramp the more aggressive the spring has to be to repress lofting and float. I am curious as to why the tech suggested new retainers?

Remember that lift is free (sort of). Finally, if you do go larger on the cam and go with 1.8 rockers, make sure to check piston to valve clearance.

-X- · 10-03-2008, 06:01 PM

Well, it was indeed a lifter that failed. The knocking was the lifter against the cam lobe, so that's toast as well. They have to pull the heads off to see if the bore hole is damaged, and if so, the bottom end has to be replaced.

If a new bottom end is needed, what should I go with? I'd want to keep the top end stuff to minimize costs, of course.

Any ideas on the best route to take here?

Z1LE · 10-04-2008, 02:43 PM

That depends on how much you want to spend, and what you plan on doing with the car in the future. If the bore is messed up you wil have to sleeve the hole, if you have to do that you might as well sleeve the whole block. That can be very expensive, but you can increase the bore size to 4.125" without issue. A nice alternative would be an LS3 block which I think are now available. This block comes with a 4.063" bore. LS2 blocks can be had for under $1000 now and they offer a 4.000" bore. your block has a 3.898" bore for reference. If you go with these blocks you can work the chambers of the heads to accomodate the increase. There are also many short block options out there ranging from stock style to all out turbo/blower/nitrous.

-X- · 10-04-2008, 03:08 PM

I was looking at Cartek's X-Series LS2 block packages (366 looks good) and also Texas Speed's LS6 shortblock ($2800) as well. Hopefully the block can be salvaged but I'm expecting the worst. Already going through withdrawal and now it looks like I'll have to sell my Audi to pay for the new build. I might even just go longblock and sell everything that comes out.

All this after I just spent $2400 on wheels and another $2000 on LG coilovers, ultra rare Mallett sways and a DTE diff brace. The wheels are on but not the suspension pieces.