jtz28

Three lifters had broken plunger retainers. All the material can not be accounted for and has likely dropped into the bottom-end of the motor.


Two additional lifter had cracked plunger retainers, athough it's difficult to see in this image.



Here is the crank. Front of motor is to the right. Notice the spun 5 and 6 rod journals



This is the mic reading on the number 6 rod journal. You can see that it cannot be turned .020 as it's already under 2.080" in diameter



These are the rod bearings for the 5 (right) and 6 (left) rods. Note that both sides of the bearing are spun.




Number 6 rod. Note the unrepairable damage on the side of the rod.




Number 5 rod. Both rods have severe grooving and pitting on the bearing contact surfaces





These are the pictures of the rest of my engine, please draw professional conclusions.
*A little history* *Engine Milage: 45302* *6500 Shift Point 6800 Rev Limit*
As you know I recently had my engine worked on by Arlington Motor Sports located in Arlington Texas. I had them install their Stage 2 cam package which Keith Moore insisted I run Comp R lifters so I can gain maximum mid range power. Along with the RS 239 cam the shop insisted I switched over to a shorter 7.35 hardened pushrod. Everything was professionally installed including the tuning which was done by Chris Marsh. Here are pictures that were taken of my engine after it mysteriously shutoff. The work done on my engine happened on Feb 17th 2004 approximately 800 miles ago.
I have given the owner Keith Moore the opportunity to get in contact with me. I have sent numerous emails and called several times during peak hours of the day and cannot get a single person to call me. I have sent numerous PM's to the Shop Secretary Elizabeth Moore and I have yet to gain a response.
So I am forced to ask for help from fellow mechanics.
Please no slamming AMS, I am just trying to figure out why with in 4 months of having my engine worked on this would happen.


Here's a price breakdown of what I think it would take to salvage this current motor
New (used) crank: $150
2 new rods: $25
R/R of old rods with new ones: $40 *
Resize of all rods: $100 *
Balancing: $200 *
Main bearings: $50
Rod bearings: $30
Cam bearings + install: $50 *
New oil pump: $120
Head gaskets: $30 (3-layer metal LS6 style)
Oil pump pickup O-ring: $5
Crank bolt: $5
Lifters: $180 ish dunno if I can get just 5 replacements.
Assembly labor: $200 (includes cleaning of all re-used parts to remove old metal shavings)
These prices will vary, as they are close to market on used parts... If you buy new GM parts (like a brand new crank), they are likely to double...

PREDATOR-Z

Improper preload settings. That is why those lifters are recommended with adjustable rockers. Stock ones are not if that is what u were running (or slp, Harland etc..)
If not they just were not properly preloaded.

z0sense

iTrader: (1)

Alright....me and JT had a conversation. This is what would seem to me like a collapsed lifter.

I would say that due to the spun bearing it would keep the piston at TDC. In essence this would not allow the pushrod to move and would cause the lifter to have to much preload on it.

Bascially I am saying that the lifter was caught in between the cam and the pushrod. Since the lobe of the cam was moving up and the pushrod was stationary, the lifter would have no where to go.

Also, for the record, no amount of this material in the motor (in my opinion) would cause a spun bearing as you see. It might have marred cylinder walls, etc. But not spun bearings as you see.

The motor was nearly seized up....squeaking, etc. What do others think about this possibly causing a spun bearing?

The pictures of the bearings have not been posted. Comp recommends about .006 preload (from what I am told), adjustable rockers were not recommneded by comp to me when I installed mine. With 7.350 pushrods too much preload is not an issue. Pushrod length canbe used to adjust preload. Would this be correct?

I also assumed the same thing as you, unitl I saw the pictures of the rod bearings.

PREDATOR-Z

Ah so, I didn't know about the bearings. You're talking rod bearings right?
If so how high were you reving? what cam are u using? Stock bottom? How many miles?
Rod bearings let go because of rod bolt failure. Stock bottom (low miles) are reliably good to around 6500 rpm max (LS1) anything more is a time bomb.
I've always maintained my belief that with any rev limiter over 6500 you need to a least upgrade your rod bolts to ARP's.
Now you'll see a lot of poeple saying "I rev it till 6800 or 7000 with no problem"; but untill when??

z0sense

iTrader: (1)

You know, I forgot all about rod bolts. As common as that is I should have known.

Either way, do you concur that the bearing would spin first? Or atleast that a collapsed lifter would not cause a spun bearing?

I was not really looking to see what caused the bearing to spin, more so then I thought it was the problem that caused the collapsed lifters.

Any other thoughts?

jtz28

Rev was set to shift at 6500 the cam is AMS 239/236 610/600 109lsa Rev limit at 6800
45k on current engine. Which was said to be ok by AMS shop tuner Chris Marsh

PREDATOR-Z

I've had that over- reving discussion on many other threads. And was bashed for it. But I speak from my experience (2 blown motors by FRB, both y2k). I simply do not believe anyone telling me reving a stock LS1 shortblock to 6800-7000 period.

in M6, one could have kissed the limiter on more than one occasion (or miss-shift). The stock tach. is crap with bigger cam and innacurate at hi rpm. That is why high reving racers use shift lights.
But your car is A4??

Anyways I will say it (Probably get cursed again) but that cam is way too big for a stock bottom.

In any case, I would do it right this time. Get a forged shortblock. $3000 range with exchange.
Or get another low mile block 01-02-03 and replace the rod bolts. It would cost about the same than rebuilding your motor.

Slowhawk

iTrader: (12)

An A4 put's more strain on the lower end when revving high rpms.A M6 rev's quickly to the rev limiter and during the shift goes back down to take the stress out.I have a few stock lower ends revving 7000rpm with no problems(lot's of track passes) An A4 will hold 6800 rpm a long time down the track causing bearing damage.

Taspeed

iTrader: (1)

On another note if you were spraying, over time the added stress on the crank will wear the journals. You checked the journal in at 2.080 which gives you a LOT more clearance between the bearing and journal. This clearance can cause a turned bearing. oil will just blow out if there is too much clearance and leave the bearing and journal to get caught up on each other.

SAM98WS6

preload is .008-.010" with adjustable rockers for the R lifters according to their tech line. Mine work fine and are very quiet. good luck.

Country Boy

iTrader: (24)

Just because a bearing spun, doesnt mean the piston stops. Everything still runs. The mangled retainers is from too much preload. Pushrods can only take up so much slack, but then you have to account for shaved heads, cam base circle and the lifters. The spun bearings is from lack of oil telling from the paper thin bearing. We had a local who was spraying when his oil pump failed and his bearing looks exactly the same... how many miles are on this motor? Alot of hard driving and many miles does takes its toll.

ezss

Those lifters should not collapse unless preload is setup incorrectly. You can adjust with the pushrod length, but that is not a very precise science unless you get custom lengths between 7.350 and 7.400, and from what Ive also heard is the intake and exhaust side cannot be the same length with that type of setup. This is what caused the failure of my first motor -- collapsed lifters from too much preload. And I think the actuall correct number is more like .004".

The damaged bearings could be a result of that, ie valve doesnt open and close correctly because of collapsed lifter, piston hits valve, back down.

crainholio

iTrader: (2)

I had a Comp-R lifter do the same exact thing to me. Same Comp part#, but this was an L98 350ci engine.

I installed them, preloaded to zero lash + 1/8 turn, and things were great. Throttle response was noticeably improved, no extra noise.

I drove it to work for ~2 weeks (45 miles round trip) and then did a Time Trial event at Pocono Speedway. Still ran sweet.

I was later changing the oil in preparation for an event at Lime Rock Park, and found the little steel retainer plate in two pieces stuck to my oil pan magnet. Out them came, back to Comp they went, and I got a free replacement set under warranty.

I re-installed my old stock lifters and ran them at Lime Rock, never got around to re-installing the Comp-R pieces.

AMS

I think it was something related to the oiling system or rodbolts. I think the colapsed lifters where a side effect of the other problems inside the motor. Joe was running at the track, and ran a 7.2, which was slightly slower than normal. On his next run, the car either shut down in the burnout box or right after launch.

Joe had the car trailered the shop SAT night, where Keith came to the shop at 10:30pm to put the car inside. We looked at the car on the next buisness day, and informed Joe that the car sounded like it had a bad bearing. We told Joe about several shortblocks that we knew where avalible, and he came to get the car 2 weeks later on a trailer.

Judging that it happened right after a run, it leads me to think it starved one of the bearings at launch. It just takes the oil level being slightly low for this to happen. Other than that, maybe rod bolt stretch led to bearing failure? Its hard to think that the lifter collapsed, unless it was a freak manufacturing problem. We have setup numeroues setups with these exact lifters, and never seen the problem before.

I have been online and on AIM for the last week, and have not been contacted by Joe in any way. I also check AMS' PM several times a day on various boards and have not recieved anything from him about this. There has also been no voice mail messages left about the situation. I called this morning to offer any solutions that we can, and hopefully Joe will get this fixed and get his ride back on the road soon!

Chris
AMS Racing

Jason98Zee

i would think the metal could cause a rod bearing to spin all it would have to do would be to stop oil flowing the rod bearing in return spining it or "stacking" the bearings. It doesnt take a whole lot but usally the bigger pieces of metal stay in the oil pan.

Its hard to say, but i would definatly say the metal from those lifters didnt help anything but i think the problem occured somewhere else

bigeller

iTrader: (2)

That engine was never sprayed on..

mbaskett

I see a few interesting things here. From all the motors I've seen that had spun bearings due to an oiling problem, the most affected rod journals were 7 and 8 and the #5 main bearing journal. This is simply because they are the last in line to receive oil and the first to lose the oil supply when the pump fails or pressure drops. Since the 5 and 6 rod journals are the only bearings that were spun, then I'm more likely to believe that the rod bolts stretched, or they picked up some trash from elsewhere in the motor, and caused just those two to spin...

The mangled lifter plunger retainers look pretty bad, but having a lifter actually collapse, I don't see how 2 of the 5 lifters would just have cracks.... I think those cracks are caused by the lifter over pumping (not collapsing), caused by either too little preload or from the valves floating. I doubt it was from the latter, because I recall jtz28 having those really nice comp double coil valvesprings that are good to 650 lift. Continuous running with a situation like this will eventually fatigue the metal, (hence the cracks) and eventually breaking them out completely.

If you are familiar with the design of the lifter valley on the LS1's then you'll know that for these metal pieces from the lifter plunger retainters to make their way down into the bottom end of the motor, they have to be knocked upwards and out the top of the plastic lifter holders. I can easily see these metal parts bouncing around in there for many miles before one ever manages to get out, and the problem could go unnoticed for quite some time.

crainholio

iTrader: (2)

The way the oiling system is designed, a failed lifter can significantly reduce the net pressure of the overall oiling circuit. It's one big plenum cast into the block, with outlet passages to the lifters and crank.

If one or more of the Comp lifters raised the plunger enough to expose it's internal oiling passages, oil would have blown out and the overall pressure would have dropped big-time.

This would have starved the main and rod bearings for oil, no more hydrodynamic wedge between the crank and bearing, and you got localized welding.

Taspeed

iTrader: (1)

I wasn't sure since the motor swap. reguardless, I think it was a preload issue and a lifter failure. Wear over time tends to be pretty even not singled out to specific journals unless something else helps out.

eallanboggs

iTrader: (1)

A spun bearing results from excess friction due to loss of lubrication. This could result from excess clearance, streched bolts or low oil pressure which can be caused by numerous things. You should try to figure out why 5 & 6 went and 7 & 8 were unaffected. That is curious.