Engine Rebuild
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Engine Rebuild Time for an engine rebuild. I installed the short block with 50K miles on it. After three years, it was starting to leak and burn a little oil. Ran great, though. I decided to rebuild it now, rather than in the middle of the season.
LS6 Rebuild
LS6 Rebuild
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Yeah, it will. Nothing you can do about that. As long as it doesn't get too bad, I'll be happy. Just part of routine maintenance.
I started it up yesterday. Sounds pretty good. I'll put the suspension on today and get it drivable. Sometime in the next few weeks I'll get it to the dyno.
I started it up yesterday. Sounds pretty good. I'll put the suspension on today and get it drivable. Sometime in the next few weeks I'll get it to the dyno.
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This project took a lot longer than I had planned. These things usually do.
The inside didn't look too bad at all. Like I said, the short block was used, with about 50K miles on it, when installed 3 years ago.
The inside didn't look too bad at all. Like I said, the short block was used, with about 50K miles on it, when installed 3 years ago.
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Once cleaned up, it looked a lot better. I used those new rocker arms from the WS6 store.
One of the reasons for the rebuild was that it was starting to use a lot of oil; about 1-1.5 qts per week end. Some was being burnt, and some was leaking. When I took the engine apart, I found some of the oil pan and front cover bolts were loose. So I used safety wire to put them back in.
I changed the intake. I decided to use the Edelbrock part, only because it had a lower profile. It just barely fits under the hood.
I also changed the cam
And this is the end result. Gained some HP, lost some torque.
This is the tune from 3 years ago.
One of the reasons for the rebuild was that it was starting to use a lot of oil; about 1-1.5 qts per week end. Some was being burnt, and some was leaking. When I took the engine apart, I found some of the oil pan and front cover bolts were loose. So I used safety wire to put them back in.
I changed the intake. I decided to use the Edelbrock part, only because it had a lower profile. It just barely fits under the hood.
I also changed the cam
And this is the end result. Gained some HP, lost some torque.
This is the tune from 3 years ago.
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Ahh. According to that pull, the motor wasn't done yet. Looks like it's going to want to rap out to 7k. Will probably make more once it's broken in too. When I refreshed my LT1 back in 2015 I must have made 20 pulls on the dyno and I rolled off at like 248whp. Went back after 1 race and it was up to 27Xwhp and I had to plate down. Next season it crept up to 27Xwhp with the restrictor in place. Now it's creeping down, but I have plenty of restrictor left in it to keep making the numbers.
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I built it to run to 7K. I'll reset the redline and run it up that high if I need to.
I generally don't worry too much about how much power it does or doesn't make. The parts will make what the parts will make. I asked them to give a nice safe tune that will run forever. Ultimate power isn't as important to me as durability. I think it's going to be fun.
I generally don't worry too much about how much power it does or doesn't make. The parts will make what the parts will make. I asked them to give a nice safe tune that will run forever. Ultimate power isn't as important to me as durability. I think it's going to be fun.
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Ran this week end in Pueblo. Bad weather on Saturday, with some rain, cold, and even a little bit of snow. Sunday was much better; cold in the morning, but the sun came out and it was a great day.
How did the new engine do? Great! Ran strong and smooth all week end. Pulled strong out of the corners, and ran smooth with a redline of 7,000. I even used 5th gear at the end of the front stretch and actually gained speed in 5th! That's a first.
I'm pretty happy with the results. The new engine and some other changes made it a whole new car. I just need to learn how to drive this "new" car again.
How did the new engine do? Great! Ran strong and smooth all week end. Pulled strong out of the corners, and ran smooth with a redline of 7,000. I even used 5th gear at the end of the front stretch and actually gained speed in 5th! That's a first.
I'm pretty happy with the results. The new engine and some other changes made it a whole new car. I just need to learn how to drive this "new" car again.
Last edited by .boB; Apr 16, 2019 at 09:30 AM.
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Contrary to popular belief, you can destroy an LS engine on the road course. It's not easy, but you can do it if you try hard enough. I think it slowly went. I struggled all week end to make a decent time; I was 3-4 seconds slower than normal. And that was on new Hoosiers! Then it started idling bad Sunday afternoon, and then wouldn't run above 2,500 or so. We called it a day.
I was hoping it would be something simple like a fuel [pump. But that checked out OK.
A compression test revealed the problem. Very little compression in #1. No change with a little oil.
The valves look good under the cover.
My bet is at 7,000 rpm, the rod stretched and the piston and head tried to occupy the same space at the same time. I don't remember a lot from HS physics class, but I seem to recall that's a bad thing.
This time I think I'll call TSP and order up an assembled long block. Then I can make the switch in a week'ish.
Won't make the race in July. Probably not in August, either. Oh, well. That's the way it goes sometimes.
I was hoping it would be something simple like a fuel [pump. But that checked out OK.
A compression test revealed the problem. Very little compression in #1. No change with a little oil.
The valves look good under the cover.
My bet is at 7,000 rpm, the rod stretched and the piston and head tried to occupy the same space at the same time. I don't remember a lot from HS physics class, but I seem to recall that's a bad thing.
This time I think I'll call TSP and order up an assembled long block. Then I can make the switch in a week'ish.
Won't make the race in July. Probably not in August, either. Oh, well. That's the way it goes sometimes.
So. . . Whatcha doin with the old block? 
One thing I have to plug here is crankcase venting. IMO it is insufficient on an LS motor. My 98 Chevy truck with a 350 has a 3/4" breather line from the factory. When I bumped up from the LT1 3/8" breather to the truck valve cover and breather line the difference was staggering. About 15whp staggering and it no longer pushes oil out the rear main seal. It worked so well that I decided to do it to my 454 supercharged dually as well. Irrelevant to the failure, I know, but seeing how you are back at the drawing board this is something worth implementing in the new build. You're going 408 right?
One thing I have to plug here is crankcase venting. IMO it is insufficient on an LS motor. My 98 Chevy truck with a 350 has a 3/4" breather line from the factory. When I bumped up from the LT1 3/8" breather to the truck valve cover and breather line the difference was staggering. About 15whp staggering and it no longer pushes oil out the rear main seal. It worked so well that I decided to do it to my 454 supercharged dually as well. Irrelevant to the failure, I know, but seeing how you are back at the drawing board this is something worth implementing in the new build. You're going 408 right?
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I'm using the upgraded crankcase venting, and that seems to work well.
The current engine is a mostly stock LS6. The short block had about 50,000 miles + 4 racing seasons on it when I overhauled it. Rings, bearings, gaskets, etc. But still the same crank and rods. The block was cleaned and honed, but that's about it.
A big b427 monster motor would be fun. But that's a lot of coin, and a lot of strain on the rest of the driveline. Probably not worth it. I'll go with a simple stroker crank, about 395 cubes. Nothing radical. But the cost of a 393 and a 347 is about the same, so why not?
Not sure what I'll do with the old engine. If it's rebuildable, I'll do that and keep it for a spare. If not..... ? Might make a nice coffee table.
The current engine is a mostly stock LS6. The short block had about 50,000 miles + 4 racing seasons on it when I overhauled it. Rings, bearings, gaskets, etc. But still the same crank and rods. The block was cleaned and honed, but that's about it.
A big b427 monster motor would be fun. But that's a lot of coin, and a lot of strain on the rest of the driveline. Probably not worth it. I'll go with a simple stroker crank, about 395 cubes. Nothing radical. But the cost of a 393 and a 347 is about the same, so why not?
Not sure what I'll do with the old engine. If it's rebuildable, I'll do that and keep it for a spare. If not..... ? Might make a nice coffee table.
Bob consider your stroke limitation vs oil pan and steering rack. You're pretty much limited to 3.75" unless you do something with the steering rack height because the crank throws will hit the oil pan where it tucks in by the rack otherwise. If you want more inches, bigger bore is the answer. 4.185x3.46 will net you a nice 388 inch motor with no extra piston speed, but all the bore size to flow more air through the heads which is where your power comes from anyway.
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Bob consider your stroke limitation vs oil pan and steering rack. You're pretty much limited to 3.75" unless you do something with the steering rack height because the crank throws will hit the oil pan where it tucks in by the rack otherwise. If you want more inches, bigger bore is the answer. 4.185x3.46 will net you a nice 388 inch motor with no extra piston speed, but all the bore size to flow more air through the heads which is where your power comes from anyway.
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A new 388 engine will cost me about $8K. Not planned for in my summer budget. Although I have the money, I'm reluctant to spend it right now. Who knows what the next few months hold for all of us?
We have three races left. If I ordered the engine today, I wouldn't receive it soon enough to get the car ready for the second event. So, do I want to spend the money and do all the work for 1 race week end? I have to admit, I do not. I have other things on my plate right. Thrashing in the garage in the summer heat was not on my To Do list.
So I'm going to bag this screwed up season. I'll replace the engine as a winter project.
If we go back to in-car instruction, then I'll sign up for that. I love instructing. But I don't have a car to do lead-follow instructing with. If they have trouble finding instructors (like they did last week) I'll consider renting a car for the week end. That might be fun.
We have three races left. If I ordered the engine today, I wouldn't receive it soon enough to get the car ready for the second event. So, do I want to spend the money and do all the work for 1 race week end? I have to admit, I do not. I have other things on my plate right. Thrashing in the garage in the summer heat was not on my To Do list.
So I'm going to bag this screwed up season. I'll replace the engine as a winter project.
If we go back to in-car instruction, then I'll sign up for that. I love instructing. But I don't have a car to do lead-follow instructing with. If they have trouble finding instructors (like they did last week) I'll consider renting a car for the week end. That might be fun.
