[Joshinator99]

Originally Posted by laynlo15

We safely made 707/662 on the stock Lt1 long block with a 2300 Maggie, Toohighpsi Port Injection, stock exhaust on E65. We did use the JMS boost pump but the rest of the fueling is from the stock High and low side fuel system. We also ran 9.86@142 with this set up on stock suspension except for Phastek lowered springs, lost 100 lbs with the drag pack which for sure helps out on the ET and MPH with less rotating mass.

Yeah, keep in mind that even at that level (which is really great for a SBE), you’re probably 831 crank HP. Still nearly 10% away from a 2x safety margin (910 HP) and still a whopping 40% off from a 3x safety margin (1365 HP). You’re keeping the fueling right on point so you’re probably going to be fine but as you know, there’s never any guarantees…. I wonder if we should start taking bets on how long before you need drop-in pistons…but I don’t want to jinx you.

[oldman]

AFAIK GM had an issue with the lighten LT1 crank and hence the LT4 has a solid 7&8 rod journal or "pin" as well as a fillet radii vs undercut ends, different steel (that is from memory. I'll cut and paste below). So HP probably is not the limiting factor but rather torque. At the stock LT4 torque level GM felt the LT1 crank was inadequate.

IMO a real crank is needed at 750 ish HP and / or 650 ft-lbs. I did not do it and I feel that will be where my engine fails if it does fail before 100K. GM felt a better crank was needed at 650HP and /or 650 ft-lbs

Any build I talk about should have a MTB failure of 100,000 miles, drive it like you stole it; also note that a manual is probably harder on the rear rod journal vs an auto.

TSP aftermarket stroker is rated upto 950 HP: https://smgspeed.com/product/tsp-for...t-sump-oiling/


Rotating assembly – Each component of the rotating assembly is unique to the LT4 to support the cylinder pressures the boosted engine is capable of generating, as well as the unique requirements for a lower compression ratio. Elements include:

A 1528MV forged steel crankshaft with tungsten balancing inserts, ground pin collars and intermediate pin drills for rods 1-6
A lightweight, forged 6061 aluminum damper with a T6 anodized hub and an iron inertia ring (the LT1 uses an iron damper)


If I ever go into my engine again (other than change valve springs), I'm going LT4 or better crank, LT4 damper, and look into the best trust bearing upgrade, and a Zl1 clutch, oh and I'd stud the mains (already studded the heads).

[Kerry]

Hey Im just one person. But this engine was tuned perfectly by looking at the spark plug and the piston top. Timing was pretty low and fuel was in the 11.8 wide open. No it did not hydro lock at any point. No deto. Here's what happened to number 4 rod at somewhere north of 1000 crank sbe. I think if you start dancing at high 700s to mid 800s wheel that's the danger zone. Just 1 persons thoughts. I think number 2 left the chat first and took 1 out beings their brothers on the same journal.

[adamjwilson]

that hurts!

[Kerry]

Some say when you mod its not if it will break but when. lol Thats how you know where the real limit is. I was planning to do drop ins in another month and just kinda kept sneaking up on power over a period of time. Now I had to buy another block and do drop ins ha! So far so good with about 10000 miles north of 800.

[Casper the friendly G]

Originally Posted by JANNETTYRACING

We have never seen a rod bolt failure.

We often spin the engines 7200 with cams.

Ted.

What the highest miles you have seen on your builds?

[JANNETTYRACING]

Originally Posted by Casper the friendly G

What the highest miles you have seen on your builds?

192,000 then pulled the engine and supercharger and sold them both in perfect condition, replace with a 427

[Casper the friendly G]

Originally Posted by JANNETTYRACING

192,000 then pulled the engine and supercharger and sold them both in perfect condition, replace with a 427

What year Camaro was this? Auto or manual trans?

[sr71bb]

Originally Posted by Katech_Mike

We don't like to push stock LT1 shortblocks much further than 700RWHP on E85 for durability reasons.

On pump gas I really don't even like to push them past about 650RWHP.

I would recommend upgrading to a forged shortblock if you want to make more than 700RWHP. We offer a good budget forged shortblock that will take 1,000RWHP.

Ok I think the amount of power that a STOCK LT1 can handle is application specific. For example ROAD RACING an LT1 is probably the HARDEST thing on the internals of an engine.

Under CONSTANT de-acceleration the stock rods and pistons take a real beating because the rods can stretch trying to slow the piston speed down from the higher RPM limits to the SUDDENLY lower RPM levels. In effect the engine can pull itself apart resulting in rod failure and piston failure. ARP rod bolts btw can help but not prevent breakage, Here below is a picture of what that looks like on my own engine. At the time THIS stock LT1 (my second engine) was making about 550WHP and it was PERFECTLY tuned running on E85.

This is NOT uncommon in a road racing application if the car is pushed to the limit particularly in track mod where the LOWEST RPM level the car sees is somewhere around 4500 RPM even in the slowest of corners (A10 trans). At the time I was daily driving this car with 2-3 track days a month.

So I would take Mike's advice on getting some forged internals but I would do that at even a lower power level IF road racing your LT1 is your thing. BTW I currently am running an LME fully forged 416 with ARP head studs, AND ARP studded main bolts. I have the RPM limiter set at 6600 RPM.

[JANNETTYRACING]

Originally Posted by Casper the friendly G

What year Camaro was this? Auto or manual trans?

it happens it was not a camaro, it was a GMC Denali we supercharged with 8000 miles on it and added other mods to the tune of 700 HP

It is a mobile office, Tows heavy equipment to and from jobs, participated in all the Farmtruck Real street races in the northeast, and other drag events at Thompson motor speedway 500 ft drags, and Test and tunes etc.

You asked what was the highest mileage on one of my builds.

The 850 HP 427 now has over 100K on it.

It is all relative, the LT is stronger than the LS.

We build hundreds of cars every year in varying levels of performance.

We can't possibly keep track of them all as far as mileage goes, but No news is good news in this industry.

Ted.

[JANNETTYRACING]

Originally Posted by sr71bb

Ok I think the amount of power that a STOCK LT1 can handle is application specific. For example ROAD RACING an LT1 is probably the HARDEST thing on the internals of an engine.

Under CONSTANT de-acceleration the stock rods and pistons take a real beating because the rods can stretch trying to slow the piston speed down from the higher RPM limits to the SUDDENLY lower RPM levels. In effect the engine can pull itself apart resulting in rod failure and piston failure. ARP rod bolts btw can help but not prevent breakage, Here below is a picture of what that looks like on my own engine. At the time THIS stock LT1 (my second engine) was making about 550WHP and it was PERFECTLY tuned running on E85.

This is NOT uncommon in a road racing application if the car is pushed to the limit particularly in track mod where the LOWEST RPM level the car sees is somewhere around 4500 RPM even in the slowest of corners (A10 trans). At the time I was daily driving this car with 2-3 track days a month.

So I would take Mike's advice on getting some forged internals but I would do that at even a lower power level IF road racing your LT1 is your thing. BTW I currently am running an LME fully forged 416 with ARP head studs, AND ARP studded main bolts. I have the RPM limiter set at 6600 RPM.

You are absolutely correct the Road coarse is the ultimate challenge for any engine.

Looking at your engine I would bet my career on it that there was oil starvation to those rods as they are the most vulnerable which causes the bearing to grab hold of the crank and break the rod.

A dry sump oiling system would have prevented this failure.

Ted.

[sr71bb]

Originally Posted by JANNETTYRACING

You are absolutely correct the Road coarse is the ultimate challenge for any engine.

Looking at your engine I would bet my career on it that there was oil starvation to those rods as they are the most vulnerable which causes the bearing to grab hold of the crank and break the rod.

A dry sump oiling system would have prevented this failure.

Ted.

Well as you are more aware than most it is so difficult to determine the INITIAL cause of an engine failure but I have been told TED that I can break a hammer in a sand box so you may very well be right. The pistons were in pieces and the rods were twisted on the ones that were still in the engine and the failure came after I de-accerlerated VERY QUICKLY into a set of twisties on a road course. I windowed the block in two places and I even damaged the oil pan when the engine pieces came apart and hit the inside of the pan. This is the MARIO ANDRETTI effect. He either won or you wound up with pieces at the end of the race.

[Casper the friendly G]

Originally Posted by sr71bb

Ok I think the amount of power that a STOCK LT1 can handle is application specific. For example ROAD RACING an LT1 is probably the HARDEST thing on the internals of an engine.

Under CONSTANT de-acceleration the stock rods and pistons take a real beating because the rods can stretch trying to slow the piston speed down from the higher RPM limits to the SUDDENLY lower RPM levels. In effect the engine can pull itself apart resulting in rod failure and piston failure. ARP rod bolts btw can help but not prevent breakage, Here below is a picture of what that looks like on my own engine. At the time THIS stock LT1 (my second engine) was making about 550WHP and it was PERFECTLY tuned running on E85.

This is NOT uncommon in a road racing application if the car is pushed to the limit particularly in track mod where the LOWEST RPM level the car sees is somewhere around 4500 RPM even in the slowest of corners (A10 trans). At the time I was daily driving this car with 2-3 track days a month.

So I would take Mike's advice on getting some forged internals but I would do that at even a lower power level IF road racing your LT1 is your thing. BTW I currently am running an LME fully forged 416 with ARP head studs, AND ARP studded main bolts. I have the RPM limiter set at 6600 RPM.

How many miles on this setup? What happened to the first engine?

[Katech_Mike]

Originally Posted by JANNETTYRACING

You are absolutely correct the Road coarse is the ultimate challenge for any engine.

Looking at your engine I would bet my career on it that there was oil starvation to those rods as they are the most vulnerable which causes the bearing to grab hold of the crank and break the rod.

A dry sump oiling system would have prevented this failure.

Ted.

I would absolutely agree with this.

Most road course LT1 failures that we've seen have been Camaro wet sumps. Many of them run at Daytona or other tracks with high speed high sustained G force turns which starves the factory wet sump oiling system.