LS 1 questions
08-21-2019, 09:22 AM
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LS 1 questions My son picked up a low mile LS1 three years ago.
He has installed it in a 1956 GMC pickup truck that he has been custom building.
The engine has been started up several times, but for short durations only as it has been absent of any coolant.
The truck recently went to a pro shop for the final electrical work.... engine wiring, new instrument panel wiring, fuel pump wiring, etc.
As they were about to run the engine and test things out, they added coolant to the system.
As they were attempting to start the engine, it locked up as though it hydro-locked, and will now not turn over, suspecting that a connecting rod has become bent.
He has no recourse against the seller due to it having been purchased 3 years ago, so there is no consideration for that.
Questions:
What, if any, are the common issues with this LS1 regarding head gaskets, cylinder block and/or cylinder heads cracking and leaking coolant into a cylinder?
If a rod has bent (during starter motor action only), what are any further issues to be concerned with?
Is the LS1 easily and cost effectively rebuildable as are it's predecessors?
Any known issues that would suggest NOT rebuilding this engine?
If these are typically rebuildable, what are some average costs?
I will appreciate any expert opinions or suggestions.
Thank you,
Rick E. aka RicardoMarine on the marine engine forums.
He has installed it in a 1956 GMC pickup truck that he has been custom building.
The engine has been started up several times, but for short durations only as it has been absent of any coolant.
The truck recently went to a pro shop for the final electrical work.... engine wiring, new instrument panel wiring, fuel pump wiring, etc.
As they were about to run the engine and test things out, they added coolant to the system.
As they were attempting to start the engine, it locked up as though it hydro-locked, and will now not turn over, suspecting that a connecting rod has become bent.
He has no recourse against the seller due to it having been purchased 3 years ago, so there is no consideration for that.
Questions:
What, if any, are the common issues with this LS1 regarding head gaskets, cylinder block and/or cylinder heads cracking and leaking coolant into a cylinder?
If a rod has bent (during starter motor action only), what are any further issues to be concerned with?
Is the LS1 easily and cost effectively rebuildable as are it's predecessors?
Any known issues that would suggest NOT rebuilding this engine?
If these are typically rebuildable, what are some average costs?
I will appreciate any expert opinions or suggestions.
Thank you,
Rick E. aka RicardoMarine on the marine engine forums.
Last edited by RicardoMarine; 08-21-2019 at 09:33 AM.
08-21-2019, 12:09 PM
#2
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My son picked up a low mile LS1 three years ago.
He has installed it in a 1956 GMC pickup truck that he has been custom building.
The engine has been started up several times, but for short durations only as it has been absent of any coolant.
The truck recently went to a pro shop for the final electrical work.... engine wiring, new instrument panel wiring, fuel pump wiring, etc.
As they were about to run the engine and test things out, they added coolant to the system.
As they were attempting to start the engine, it locked up as though it hydro-locked, and will now not turn over, suspecting that a connecting rod has become bent.
He has no recourse against the seller due to it having been purchased 3 years ago, so there is no consideration for that.
Questions:
What, if any, are the common issues with this LS1 regarding head gaskets, cylinder block and/or cylinder heads cracking and leaking coolant into a cylinder?
No common coolant leaking issues. Could he have possibly cracked a sleeve running it with no coolant?
If a rod has bent (during starter motor action only), what are any further issues to be concerned with?
As long as nothing has contacted the cylinder wall, there shouldn't be any other major issues.
Is the LS1 easily and cost effectively rebuildable as are it's predecessors?
Yes, very similar to rebuild with some differences. For example, the heads must be removed to change lifters, but no RTV is required when installing the intake manifold, etc.
Any known issues that would suggest NOT rebuilding this engine?
Check for that cracked cylinder.
If these are typically rebuildable, what are some average costs?
Depends on the depth of the rebuild. Parts are extremely common.
I will appreciate any expert opinions or suggestions.
Thank you,
Rick E. aka RicardoMarine on the marine engine forums.
He has installed it in a 1956 GMC pickup truck that he has been custom building.
The engine has been started up several times, but for short durations only as it has been absent of any coolant.
The truck recently went to a pro shop for the final electrical work.... engine wiring, new instrument panel wiring, fuel pump wiring, etc.
As they were about to run the engine and test things out, they added coolant to the system.
As they were attempting to start the engine, it locked up as though it hydro-locked, and will now not turn over, suspecting that a connecting rod has become bent.
He has no recourse against the seller due to it having been purchased 3 years ago, so there is no consideration for that.
Questions:
What, if any, are the common issues with this LS1 regarding head gaskets, cylinder block and/or cylinder heads cracking and leaking coolant into a cylinder?
No common coolant leaking issues. Could he have possibly cracked a sleeve running it with no coolant?
If a rod has bent (during starter motor action only), what are any further issues to be concerned with?
As long as nothing has contacted the cylinder wall, there shouldn't be any other major issues.
Is the LS1 easily and cost effectively rebuildable as are it's predecessors?
Yes, very similar to rebuild with some differences. For example, the heads must be removed to change lifters, but no RTV is required when installing the intake manifold, etc.
Any known issues that would suggest NOT rebuilding this engine?
Check for that cracked cylinder.
If these are typically rebuildable, what are some average costs?
Depends on the depth of the rebuild. Parts are extremely common.
I will appreciate any expert opinions or suggestions.
Thank you,
Rick E. aka RicardoMarine on the marine engine forums.
08-23-2019, 08:00 AM
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Questions:
What, if any, are the common issues with this LS1 regarding head gaskets, cylinder block and/or cylinder heads cracking and leaking coolant into a cylinder?
No common coolant leaking issues. Could he have possibly cracked a sleeve running it with no coolant?
Joe, the engine was started up for seconds only, simply to test and see if it would fire up.
It was not operated long enough for any damage to have occurred to a cylinder sleeve.
If a rod has bent (during starter motor action only), what are any further issues to be concerned with?
As long as nothing has contacted the cylinder wall, there shouldn't be any other major issues.
He has yet to tear it down...…. hopefully soon!
Is the LS1 easily and cost effectively rebuildable as are it's predecessors?
Yes, very similar to rebuild with some differences. For example, the heads must be removed to change lifters, but no RTV is required when installing the intake manifold, etc.
Understood and thank you.
Any known issues that would suggest NOT rebuilding this engine?
Check for that cracked cylinder.
We have not assumed anything as of yet, and in particular a cracked cylinder!
If these are typically rebuildable, what are some average costs?
Depends on the depth of the rebuild. Parts are extremely common.
Thank you!
Rick E. aka RicardoMarine on the marine engine forums.
What, if any, are the common issues with this LS1 regarding head gaskets, cylinder block and/or cylinder heads cracking and leaking coolant into a cylinder?
No common coolant leaking issues. Could he have possibly cracked a sleeve running it with no coolant?
Joe, the engine was started up for seconds only, simply to test and see if it would fire up.
It was not operated long enough for any damage to have occurred to a cylinder sleeve.
If a rod has bent (during starter motor action only), what are any further issues to be concerned with?
As long as nothing has contacted the cylinder wall, there shouldn't be any other major issues.
He has yet to tear it down...…. hopefully soon!
Is the LS1 easily and cost effectively rebuildable as are it's predecessors?
Yes, very similar to rebuild with some differences. For example, the heads must be removed to change lifters, but no RTV is required when installing the intake manifold, etc.
Understood and thank you.
Any known issues that would suggest NOT rebuilding this engine?
Check for that cracked cylinder.
We have not assumed anything as of yet, and in particular a cracked cylinder!
If these are typically rebuildable, what are some average costs?
Depends on the depth of the rebuild. Parts are extremely common.
Thank you!
Rick E. aka RicardoMarine on the marine engine forums.
08-26-2019, 03:14 AM
#4
Did you pull the plugs and try and turn it over. Doubt if it bent anything just turning it over. Very unlikely that it cracked anything too, unless it already was. Pull all the plugs and bump it over slowly to get the water out. Watch all the holes to see how many spew water or which ones. Then pull it apart to look at the head gaskets. If they look good then you may have a cracked head or two. The guy you bought it off of may have had a turbo on it or sprayed it and blown the head gaskets. Hopefully there is no more damage. I would call that guy you got it from and at least say something or ask for your money back. You never know he may help you out. Worth a shot. Best of Luck. If he doesn't, put his name, address, and phone number on here and Yellow Bullet to let the members ride him like a stick pony. And ride him they will. I'm sure you have plenty of witnesses. Sucks having to go through this kind of crap though.
08-26-2019, 12:35 PM
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.....
Did you pull the plugs and try and turn it over.
Yes, that was the first thing that was done.
Even with all of the spark plugs removed, it will reach a point in rotation where it will turn no further.
Doubt if it bent anything just turning it over.
And I would typically agree. I am no stranger to the previous SBCs.
Very unlikely that it cracked anything too, unless it already was. Pull all the plugs and bump it over slowly to get the water out.
Watch all the holes to see how many spew water or which ones.
There is no water in it, just coolant.
Again, it will not turn over any more than partially.
Then pull it apart to look at the head gaskets. If they look good then you may have a cracked head or two.
Of course...…. that will be his next step.
The guy you bought it off of may have had a turbo on it or sprayed it and blown the head gaskets. Hopefully there is no more damage. I would call that guy you got it from and at least say something or ask for your money back. You never know he may help you out. Worth a shot.
Best of Luck. If he doesn't, put his name, address, and phone number on here and Yellow Bullet to let the members ride him like a stick pony. And ride him they will. I'm sure you have plenty of witnesses. Sucks having to go through this kind of crap though.
As I said earlier, there is no recourse against the seller. It has been 3 years or so since my son bought it.
Thank you for your thoughts!
Yes, that was the first thing that was done.
Even with all of the spark plugs removed, it will reach a point in rotation where it will turn no further.
Doubt if it bent anything just turning it over.
And I would typically agree. I am no stranger to the previous SBCs.
Very unlikely that it cracked anything too, unless it already was. Pull all the plugs and bump it over slowly to get the water out.
Watch all the holes to see how many spew water or which ones.
There is no water in it, just coolant.
Again, it will not turn over any more than partially.
Then pull it apart to look at the head gaskets. If they look good then you may have a cracked head or two.
Of course...…. that will be his next step.
The guy you bought it off of may have had a turbo on it or sprayed it and blown the head gaskets. Hopefully there is no more damage. I would call that guy you got it from and at least say something or ask for your money back. You never know he may help you out. Worth a shot.
Best of Luck. If he doesn't, put his name, address, and phone number on here and Yellow Bullet to let the members ride him like a stick pony. And ride him they will. I'm sure you have plenty of witnesses. Sucks having to go through this kind of crap though.
As I said earlier, there is no recourse against the seller. It has been 3 years or so since my son bought it.
Thank you for your thoughts!
08-28-2019, 08:49 AM
#6
TECH Resident
Sounds like something on top of a piston.. Get -Rent a bore scope and look in the cylinders. Also the starters on these engines will bend a rod if hydrolocked, had it happen on a 4.8 I was working on...
08-29-2019, 07:17 PM
#7
I would bet on a starter gone bad before I would bet on water in a cylinder hydrolocking it. You just don't really see that on LS motors.
I would try to turn it by hand with a ratchet before I got to pulling any parts off.
Start there. If it is indeed seized pull the plugs like mentioned above and see if water comes out. If water does come out tear it down and assess the damage.
If it seized during cranking only it usually will only damage the starter if anything.
I would try to turn it by hand with a ratchet before I got to pulling any parts off.
Start there. If it is indeed seized pull the plugs like mentioned above and see if water comes out. If water does come out tear it down and assess the damage.
If it seized during cranking only it usually will only damage the starter if anything.
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09-12-2019, 07:15 AM
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Update:
This engine has now been torn down.
What we thought was a bent rod, is actually a bent, twisted and broken rod.
The rod has caused a small fracture in the cylinder block just outside of where the main bearing cap contacts the cylinder block.
It could be TIG weld repaired.
Piston and cylinder look great.
Crankshaft throw also looks great.
Head gaskets do not show signs of failure.
I think that he will end up buying a reman ..... not sure yet from which company.
This engine has now been torn down.
What we thought was a bent rod, is actually a bent, twisted and broken rod.
The rod has caused a small fracture in the cylinder block just outside of where the main bearing cap contacts the cylinder block.
It could be TIG weld repaired.
Piston and cylinder look great.
Crankshaft throw also looks great.
Head gaskets do not show signs of failure.
I think that he will end up buying a reman ..... not sure yet from which company.
09-13-2019, 09:17 AM
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However, we have no reason to believe that the shop (who did the electrical work) did anything wrong.
As said, my son did a few very short dry starts (i.e., no coolant in engine) just to hear it fire up, and not long enough for any over-heating to have occurred.
Had the shop run the engine without coolant (for any duration and encountered an over-heat), and then added coolant later on, we would now see some tell-tale signs.
The cylinders look perfect and the pistons look perfect, including the piston that encountered the broken rod.
Just to be clear, I fully understand the locking or lock-up force that a hydro-lock would cause.
I can see this stopping the flywheel and starter motor..... but man...…. that must be an extremely powerful starter motor in order to break a rod!
For me, it shows that GM's powdered-metal connecting rod process lacks well thought out engineering!
Note the crack that I circled in red .
09-13-2019, 12:43 PM
#11
And the reason I disagree is the reason I call bs on the rod breaking during cranking.
I have seen starter nose cones break off and starters go to **** trying to crank on an engine that had water in it, but in my 20 years as a tech, racer, friend of high end speed shop owners and tuners, forum avid reader and participant... I have never seen or heard of a rod break during cranking.
The GM powdered metal rod has held shockingly high power levels and RPM since it was introduced. The gen 3's could sustain 7000 rpm and have survived at WELL over 1000 hp in multiple builds. The gen 4 rods are holding closer to 8k rpm and I don't even know how much power.
I know Richard Holdener has many dyno tests of gen 3 motors and one of them, the 6.0, didn't come apart until 1500 hp with stock rods. For a factory piece, they're nothing short of a miracle really.
If you haven't read on the big bang motors you should check it out. They have done hundreds of dyno runs on stock rods at over 1000 hp
09-19-2019, 07:17 AM
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To further add to the story and my thoughts:
There are absolutely no signs of damage that would have occurred had this engine been running.
Other than where the broken rod had pushed one time against the lower web, there are no other signs of cylinder block damage.
No odd markings on the broken connecting rod that would indicate that the engine was running at the time.
No piston skirt damage.
No cylinder wall damage.
Starter motor appears to be in tact.
This is indeed a strange scenario.
Rick E.
There are absolutely no signs of damage that would have occurred had this engine been running.
Other than where the broken rod had pushed one time against the lower web, there are no other signs of cylinder block damage.
No odd markings on the broken connecting rod that would indicate that the engine was running at the time.
No piston skirt damage.
No cylinder wall damage.
Starter motor appears to be in tact.
This is indeed a strange scenario.
Rick E.
Last edited by RicardoMarine; 09-19-2019 at 08:15 AM.
09-21-2019, 06:07 PM
#16
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The pic showing the crack circled in red actually looks pretty nasty when you blow it up. You can see where the rod tried to punch through the block and there appears to be some major cracks running more horizontally through the block from that point. Maybe in person it's not that bad, but the pic is scary when you zoom in.
10-01-2019, 06:45 AM
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Thanks for all of the replies.
From every indication, this was a one-time-revolution ordeal. There are NO markings that would indicate that the crankshaft and/or rod made more than one revolution (if that) when the damage occurred.
Meanwhile, he has ordered another engine, and will try to sell these parts.
From every indication, this was a one-time-revolution ordeal. There are NO markings that would indicate that the crankshaft and/or rod made more than one revolution (if that) when the damage occurred.
Meanwhile, he has ordered another engine, and will try to sell these parts.