Confirmed; Another One Bites the Dust
Thread Starter
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
Confirmed; Another One Bites the Dust
Well, got confirmation today that my LT4 has spun bearings in the bottom end. Was hoping for the best and the issue was a clutch or accessory. Just going to put this one back to stock.
I would like to suggest to any of you that autox and run DOT R Compound tires such as Hoosier A6's; at least install a windage tray or road race oil pan. We suspect oil starvation to be the cause for the failure.
I would like to suggest to any of you that autox and run DOT R Compound tires such as Hoosier A6's; at least install a windage tray or road race oil pan. We suspect oil starvation to be the cause for the failure.
Melting Slicks
Joined: Jun 2004
Posts: 3,253
Likes: 2
From: Castro Valley CA
My condolences as well. Hope you get it running soon.
My LT1 finally packed it in after 13 years and probably 200 track hours. I've been running Pirelli slicks for the last 3 years and DOT R's for years before that, totally stock engine and pan. Redline 20W-50 for the last 5 years. What broke on mine was that the teeth stripped on the cam sprocket that drives the water pump; causing overheating plus "tooth decay" throughout the engine. My point is, the stock pan and pump may not be entirely at fault. I should add, in your case it certainly was!
My LT1 finally packed it in after 13 years and probably 200 track hours. I've been running Pirelli slicks for the last 3 years and DOT R's for years before that, totally stock engine and pan. Redline 20W-50 for the last 5 years. What broke on mine was that the teeth stripped on the cam sprocket that drives the water pump; causing overheating plus "tooth decay" throughout the engine. My point is, the stock pan and pump may not be entirely at fault. I should add, in your case it certainly was!
Last edited by Sidney004; Nov 7, 2013 at 10:39 PM.
Team Owner
Joined: Sep 2003
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Just curious.
There was a post not too long ago about the oil pump port or housing that is known to cause LTx oil starvation problems at high revs.
I mention this for your mod list on the fresh motor.
There was a post not too long ago about the oil pump port or housing that is known to cause LTx oil starvation problems at high revs.
I mention this for your mod list on the fresh motor.
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Safety Car
Joined: Feb 2000
Posts: 4,564
Likes: 110
From: Austin Texas
When I built my 355 first time...I figured I'd be sneaky and leave the stock pan on (against my machinist's "suggestion") so it wasn't so obvious that I'd done motor work.
It survived for 5 months of autocrossing...until I did some track days at Texas World. Sustained high-g loading in the carousel in my sig picture starved it of oil. As a matter of fact...it was this particular weekend that I did the damage. The next event weekend it finished it off...3 main and 4 rod bearings. To make matters worse...it cracked the crank as well!
I've got over 40k miles on the SECOND rebuild...lots of track and autox events. No issues with the Canton RR pan and oiling with it.
Putting an AccuSump on it over the winter. You can never have too much insurance.
Last edited by 1991Z07; Nov 8, 2013 at 09:24 AM.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Here are a few pictures of where Will ported mine.
And here are a few showing mods to get the lifter valley to drain better
In this picture you can see where one side has been ported and the other side has not.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
The 90* straight cut on the (ON ANY) oil pump pick up tube causes cavitation at higher rpm.
Suggest modding the inlet to a 45* opening then roll the edges to a form a flare.
Suggest modding the inlet to a 45* opening then roll the edges to a form a flare.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Not sure what you are talking about to be honest. I can tell you that Will has a lot of experience with these motors and mine is doing fine. Been to 7000 rpms on many occasions.
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Push any engine long enough they will fail produciton engines just werent designed for this
Even the aftermarket stuff will give way at some point
Sorry to hear about the failure, its never a good time.
Even the aftermarket stuff will give way at some point
Sorry to hear about the failure, its never a good time.
Burning Brakes
Joined: May 2010
Posts: 900
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From: Cary illinois
I have been lucky so far . Stock bottom end . Big sticky tires . Nice dent in the bottom of the pan also . After some runs at Blackhawk . Pressure went to zero .Light came on and the engine died . Started back up . I ran an extra half qt. I don't see high rpm like some motors .
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Sorry to hear about the engine failure. Best of luck with the repair.
Le Mans Master
Joined: Jul 2009
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From: SF bay area C.A.
C4 of the Year Finalist
Sorry to hear that but remember the racers motto. "Race it, break it, fix it and repeat" with all the problems I had this season I should have it tatted on me.
Melting Slicks
Joined: Jan 2009
Posts: 3,482
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From: folsom california
[QUOTE
Here are a few pictures of where Will ported mine.
And here are a few showing mods to get the lifter valley to drain better
In this picture you can see where one side has been ported and the other side has not.
[/QUOTE]
I really appreciate see oiling system modifications; I never believed (based on personal experience) that a chevy small block oil system was "bullet proof" as it came from the factory.
if you ever find a copy of "Racing The Small Block Chevy", read about the EXTENSIVE oil system modifications that were done back in the day to get a small block chevy to survive endurance racing events.
with that said, the oil drain back mods to your engine are a definite upgrade.
a related drain back mod is to enlarge the drain back holes above the camshaft to allow increased splash lubrication of the camshaft lobes; some aftermarket blocks leave this area almost completely open.
Here are a few pictures of where Will ported mine.
And here are a few showing mods to get the lifter valley to drain better
In this picture you can see where one side has been ported and the other side has not.
[/QUOTE]I really appreciate see oiling system modifications; I never believed (based on personal experience) that a chevy small block oil system was "bullet proof" as it came from the factory.
if you ever find a copy of "Racing The Small Block Chevy", read about the EXTENSIVE oil system modifications that were done back in the day to get a small block chevy to survive endurance racing events.
with that said, the oil drain back mods to your engine are a definite upgrade.
a related drain back mod is to enlarge the drain back holes above the camshaft to allow increased splash lubrication of the camshaft lobes; some aftermarket blocks leave this area almost completely open.
Team Owner
Joined: Oct 2004
Posts: 81,241
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From: altered state
St. Jude Donor '05
I plug all that stuff off so its not getting whipped on the crank and work on return holes.
Start at the top with the heads. If X amount can only get through there then that same amount will only get through the block in time maybe Im wrong. LTx and Dart blocks really benefit
There are other things you can do wiht actual oil passages themselves thats usually best left to a machinist
Nothing wrong with letting the lifters sit in a pool of oil either. Opinions will differ
Start at the top with the heads. If X amount can only get through there then that same amount will only get through the block in time maybe Im wrong. LTx and Dart blocks really benefit
There are other things you can do wiht actual oil passages themselves thats usually best left to a machinist
Nothing wrong with letting the lifters sit in a pool of oil either. Opinions will differ
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
We have a couple o different discussions going on here.
In reguard to LTX's spinning rod brgs. IMO it's a combination of very tight factory brg clearance, load, oil temp and sometimes oil starvation/cavitation of the pump.
Now the brg clearance can be opened up.
Load is what it is.
High oil temps can be combated with opened up brg clearance, less windage, oil coolers and more oil capacity.
Starvation/cavitation... this is a big one. Starvation can be cured with a properly built RR oil pan. The best for the money IMO is the Champ. The opening up of the oil returns in the block help combat starvation and also decrease windage.
I personally have never had oiling system problems where we needed an Accusump/oil accumulator - Even back when our late models were wet sumps (late 1980's)... Today I still build a few limited class dirt cars that are way faster today than the late models were back then and by rules we use wet sumps and we still don't have any oiling system problems.... But you see the kind of hand work I put into blocks and the oiling systems... there is also alot of blue printing work I do to the pumps that you will never see... Then there is componet selection for pans and pumps..... Bearing clearances and oil ring gaps, cyl wall finish ect.... If your not willing or not knowlegeable enough to do all that an Accusump/oil accumulators can be a good idea if your willing to plumb one.
Cavitation is a product of the oil pump. That grinding I do on the rear main cap helps. A properly designed oil pan with a windage tray that blocks the oil pump bypass from dumping oil directly on top of the oil pump pick up tube also helps. Also alot has to do with the oil pump itself and how it's built inside.
As far as the SBC oiling system in general it's not that great. Production engines oil the camshaft first, then divert oil to the crankshaft and last the rods.... aftermarket block all have "priority main" oiling systems that have a dedicated main/crankshaft oiling circuit.
To the OP. If you just put it back stockish but intend to keep tracking it on R tires... The few things you need to change at a minimum IMO is the pan, the pump and the brg clearances. Buy the Champ RR pan and a Milodon STD volume oil pump. Set the rod and main brg clearance at .002-.0025.
Will
In reguard to LTX's spinning rod brgs. IMO it's a combination of very tight factory brg clearance, load, oil temp and sometimes oil starvation/cavitation of the pump.
Now the brg clearance can be opened up.
Load is what it is.
High oil temps can be combated with opened up brg clearance, less windage, oil coolers and more oil capacity.
Starvation/cavitation... this is a big one. Starvation can be cured with a properly built RR oil pan. The best for the money IMO is the Champ. The opening up of the oil returns in the block help combat starvation and also decrease windage.
I personally have never had oiling system problems where we needed an Accusump/oil accumulator - Even back when our late models were wet sumps (late 1980's)... Today I still build a few limited class dirt cars that are way faster today than the late models were back then and by rules we use wet sumps and we still don't have any oiling system problems.... But you see the kind of hand work I put into blocks and the oiling systems... there is also alot of blue printing work I do to the pumps that you will never see... Then there is componet selection for pans and pumps..... Bearing clearances and oil ring gaps, cyl wall finish ect.... If your not willing or not knowlegeable enough to do all that an Accusump/oil accumulators can be a good idea if your willing to plumb one.
Cavitation is a product of the oil pump. That grinding I do on the rear main cap helps. A properly designed oil pan with a windage tray that blocks the oil pump bypass from dumping oil directly on top of the oil pump pick up tube also helps. Also alot has to do with the oil pump itself and how it's built inside.
As far as the SBC oiling system in general it's not that great. Production engines oil the camshaft first, then divert oil to the crankshaft and last the rods.... aftermarket block all have "priority main" oiling systems that have a dedicated main/crankshaft oiling circuit.
To the OP. If you just put it back stockish but intend to keep tracking it on R tires... The few things you need to change at a minimum IMO is the pan, the pump and the brg clearances. Buy the Champ RR pan and a Milodon STD volume oil pump. Set the rod and main brg clearance at .002-.0025.
Will
Thread Starter
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 79
From: Monroe OH
NCM Sinkhole Donor
We have a couple o different discussions going on here.
In reguard to LTX's spinning rod brgs. IMO it's a combination of very tight factory brg clearance, load, oil temp and sometimes oil starvation/cavitation of the pump.
Now the brg clearance can be opened up.
Load is what it is.
High oil temps can be combated with opened up brg clearance, less windage, oil coolers and more oil capacity.
Starvation/cavitation... this is a big one. Starvation can be cured with a properly built RR oil pan. The best for the money IMO is the Champ. The opening up of the oil returns in the block help combat starvation and also decrease windage.
I personally have never had oiling system problems where we needed an Accusump/oil accumulator - Even back when our late models were wet sumps (late 1980's)... Today I still build a few limited class dirt cars that are way faster today than the late models were back then and by rules we use wet sumps and we still don't have any oiling system problems.... But you see the kind of hand work I put into blocks and the oiling systems... there is also alot of blue printing work I do to the pumps that you will never see... Then there is componet selection for pans and pumps..... Bearing clearances and oil ring gaps, cyl wall finish ect.... If your not willing or not knowlegeable enough to do all that an Accusump/oil accumulators can be a good idea if your willing to plumb one.
Cavitation is a product of the oil pump. That grinding I do on the rear main cap helps. A properly designed oil pan with a windage tray that blocks the oil pump bypass from dumping oil directly on top of the oil pump pick up tube also helps. Also alot has to do with the oil pump itself and how it's built inside.
As far as the SBC oiling system in general it's not that great. Production engines oil the camshaft first, then divert oil to the crankshaft and last the rods.... aftermarket block all have "priority main" oiling systems that have a dedicated main/crankshaft oiling circuit.
To the OP. If you just put it back stockish but intend to keep tracking it on R tires... The few things you need to change at a minimum IMO is the pan, the pump and the brg clearances. Buy the Champ RR pan and a Milodon STD volume oil pump. Set the rod and main brg clearance at .002-.0025.
Will
In reguard to LTX's spinning rod brgs. IMO it's a combination of very tight factory brg clearance, load, oil temp and sometimes oil starvation/cavitation of the pump.
Now the brg clearance can be opened up.
Load is what it is.
High oil temps can be combated with opened up brg clearance, less windage, oil coolers and more oil capacity.
Starvation/cavitation... this is a big one. Starvation can be cured with a properly built RR oil pan. The best for the money IMO is the Champ. The opening up of the oil returns in the block help combat starvation and also decrease windage.
I personally have never had oiling system problems where we needed an Accusump/oil accumulator - Even back when our late models were wet sumps (late 1980's)... Today I still build a few limited class dirt cars that are way faster today than the late models were back then and by rules we use wet sumps and we still don't have any oiling system problems.... But you see the kind of hand work I put into blocks and the oiling systems... there is also alot of blue printing work I do to the pumps that you will never see... Then there is componet selection for pans and pumps..... Bearing clearances and oil ring gaps, cyl wall finish ect.... If your not willing or not knowlegeable enough to do all that an Accusump/oil accumulators can be a good idea if your willing to plumb one.
Cavitation is a product of the oil pump. That grinding I do on the rear main cap helps. A properly designed oil pan with a windage tray that blocks the oil pump bypass from dumping oil directly on top of the oil pump pick up tube also helps. Also alot has to do with the oil pump itself and how it's built inside.
As far as the SBC oiling system in general it's not that great. Production engines oil the camshaft first, then divert oil to the crankshaft and last the rods.... aftermarket block all have "priority main" oiling systems that have a dedicated main/crankshaft oiling circuit.
To the OP. If you just put it back stockish but intend to keep tracking it on R tires... The few things you need to change at a minimum IMO is the pan, the pump and the brg clearances. Buy the Champ RR pan and a Milodon STD volume oil pump. Set the rod and main brg clearance at .002-.0025.
Will
And I am going to mention the forementioned grinding to open up the passage. One would think since the LTx motors were designed to produce power in he higher Ron's they would have considered cavatation and oil starvation.
Thanks for the condolences on the second blown motor.
And, just saying and may just be coincidence; my L98 lasted longer than my LT4 before failure.
Last edited by l98tpi; Nov 8, 2013 at 02:54 PM.