Rod bolt failure carnage pics- broke 2 rods @ 7200 rpms
10-03-2014, 10:07 PM
#1
Rod bolt failure carnage pics- broke 2 rods @ 7200 rpms Just a little info on the engine first.
Stock bottom end LS1 with exception to ARP rod bolts.
Motor had 497hp to the tire on StraightLine Performance's Dyno.
Was shifting and going thru the traps at 7700 rpms
Advanced induction CNC ported 243s
Solid Roller cam
Race weight 3300 lbs
best 1/4 mile 10.76 @ 126mph with only a 1.51 60 foot.
No trans brake
Yank ss4000 (this converter was actually too tight for this engine combo)
as cast vic jr. with accufab 4150 throttle body
Over 100 passes turning 7700 rpms on the stock rods.
Surprisingly, it looks like rod bolt failure was the main cause.
It blew up just after the 1,000 foot mark. At this point the car was going about 115 miles per hour and the engine was twisting 7,200 rpms.
It broke 2 connecting rods, obliterated a piston, put a hole in each side of the block, shattered the bottom of the oil pan, and bent couple of valves. Piston rings were found outside of the engine next to the motor mounts. When the internals came out the driver side of the block it ripped a huge hole in the side of the block and it took the main oil galley with it. This instantly pumped all the oil out of the motor and onto the race track. Inside the car, following the big boom, it sounded like I was driving 100 miles per hour down a dirt road. All of the engine pieces were bouncing off the race track and hitting the floor. Luckily, oil never got under the tires and the car went straight. There was so much smoke people at the starting line thought we wrecked the car.
^^^^^ big end of the number 2 rod still on the crank.
^^^^^ all that's left of the number 1 piston and rod.
^^^^^ #1 failed rod bolt, the threaded part of one of the rod bolts is still in the rod.
^^^^^The other #1 rod bolt still intact just bent to hell.
^^^^^ number 2 piston and part of the rod.
Stock bottom end LS1 with exception to ARP rod bolts.
Motor had 497hp to the tire on StraightLine Performance's Dyno.
Was shifting and going thru the traps at 7700 rpms
Advanced induction CNC ported 243s
Solid Roller cam
Race weight 3300 lbs
best 1/4 mile 10.76 @ 126mph with only a 1.51 60 foot.
No trans brake
Yank ss4000 (this converter was actually too tight for this engine combo)
as cast vic jr. with accufab 4150 throttle body
Over 100 passes turning 7700 rpms on the stock rods.
Surprisingly, it looks like rod bolt failure was the main cause.
It blew up just after the 1,000 foot mark. At this point the car was going about 115 miles per hour and the engine was twisting 7,200 rpms.
It broke 2 connecting rods, obliterated a piston, put a hole in each side of the block, shattered the bottom of the oil pan, and bent couple of valves. Piston rings were found outside of the engine next to the motor mounts. When the internals came out the driver side of the block it ripped a huge hole in the side of the block and it took the main oil galley with it. This instantly pumped all the oil out of the motor and onto the race track. Inside the car, following the big boom, it sounded like I was driving 100 miles per hour down a dirt road. All of the engine pieces were bouncing off the race track and hitting the floor. Luckily, oil never got under the tires and the car went straight. There was so much smoke people at the starting line thought we wrecked the car.
^^^^^ big end of the number 2 rod still on the crank.
^^^^^ all that's left of the number 1 piston and rod.
^^^^^ #1 failed rod bolt, the threaded part of one of the rod bolts is still in the rod.
^^^^^The other #1 rod bolt still intact just bent to hell.
^^^^^ number 2 piston and part of the rod.
Last edited by LilSlo1; 10-05-2014 at 09:49 AM.
10-04-2014, 12:02 AM
#2
Damn, my buddies z28 makes 640 on spray, i spin it to 7k, prolly has 25 passes and 20 street raves with 30 plus bottles through it...wonder if she's on borrowed time lol
That sucks though man
That sucks though man
10-04-2014, 05:05 AM
#4
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It looks more along the lines of just rod failure, not so much rod bearing failure. All the years of abuse and track passes that the metal in the rods had had enough. If you see in a couple of your pics the rod caps are still together just bent and mangled, the wrist pin end is still in the piston and no apparent wrist pin damage. Ive seen it happen a few times myself.
Either way Im sure it really sucks, nobody loves when their engine goes, but if your going to blow it better blow it up big haha.
Either way Im sure it really sucks, nobody loves when their engine goes, but if your going to blow it better blow it up big haha.
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10-09-2014, 03:03 PM
#8
Sorry to hear about this, but that's a lot of revs for a motor that wasn't spec'd for those rod bolts and their clamping strength and increased torque on the bearings. The bearings are probably what caused the failure. More detailed info here:
https://ls1tech.com/forums/generatio...oing-come.html
https://ls1tech.com/forums/generatio...oing-come.html
10-10-2014, 07:12 AM
#9
Sorry to hear about this, but that's a lot of revs for a motor that wasn't spec'd for those rod bolts and their clamping strength and increased torque on the bearings. The bearings are probably what caused the failure. More detailed info here:
https://ls1tech.com/forums/generatio...oing-come.html
https://ls1tech.com/forums/generatio...oing-come.html
. What's the new plan?
10-11-2014, 08:44 AM
#12
Don't really have a new plan. Although I'd really like to build the same combo again with good rods and see how fast I can get it to go. I think if I had a looser converter I could go low to mid 10s.
The Vic jr was as cast and I was definitely seeing distribution problems. I wanted to put a ported super Vic on it or even maybe a mast intake if I win the lottery.
Also all the cylinders were worn out and egg shaped. 2 of the cylinders had some decent scores in it too. All I did at the time I built it was garage hone it, put some file fit rings in it and a fresh set of bearings and let her eat.
I am curious as to what a fresh good bottom end would do.
I seriously had less than 3 grand into this back yard garage combo. Obviously the most expensive part was the AI ported heads.
Cam was a cheap *** solid roller I bought off eBay and the rockers were shitty cheap ebay Pro comp rockers. Those are the rockers you need tall valve covers for and have to clearence the heads to fit the rockers. Those rockers were so shitty I had to grind the valve covers so much that the stock gasket would no longer work and I had to make my own cork gasket to seal the valve covers.
The Vic jr was as cast and I was definitely seeing distribution problems. I wanted to put a ported super Vic on it or even maybe a mast intake if I win the lottery.
Also all the cylinders were worn out and egg shaped. 2 of the cylinders had some decent scores in it too. All I did at the time I built it was garage hone it, put some file fit rings in it and a fresh set of bearings and let her eat.
I am curious as to what a fresh good bottom end would do.
I seriously had less than 3 grand into this back yard garage combo. Obviously the most expensive part was the AI ported heads.
Cam was a cheap *** solid roller I bought off eBay and the rockers were shitty cheap ebay Pro comp rockers. Those are the rockers you need tall valve covers for and have to clearence the heads to fit the rockers. Those rockers were so shitty I had to grind the valve covers so much that the stock gasket would no longer work and I had to make my own cork gasket to seal the valve covers.
Last edited by LilSlo1; 10-11-2014 at 08:57 AM.
10-11-2014, 10:33 AM
#14
Going solid roller isn't as expensive as all the Ls1Tech know-it-alls say it is.
The only extra thing I bought was the Hinson rev kit. The reasoning for this wasn't so I could rev it to the moon, it was to better control the lifters and obviously not require the valve springs to control them. When I built this combo I knew it was going to be 7500 to 8000 rpm engine.
The valves I ran were NOT even light weight, they were regular Manley Pro flow valves, and the shitty ebay cheapo rockers as stated earlier weren't exactly light either.
The springs I ran were stock diameter dual springs, nothing special,basically a Pac or Patriot type spring. (I'm not sure exactly what spring was on it cause AI set up the heads for me, I just told them that I wanted the stiffest stock diameter dual spring on it that they could get).
Also, I was using 5/16" pushrods (stock diameter).
This engine never skipped a beat. It pulled hard all the way to the gear change at 7700 rpms.
I put over 100 runs on this combo and never once heard valve float.
However, a downside to this, is that I would probably change valve springs every winter to be safe. This may be too much for some people.
Also, the myth of always having to set the valves is bull **** too. If you constantly have to set the valves there is something wrong. I put about 50 runs on the car this year. I check the valves at the beginning of the year and they were fine, and I checked them again before the event I went to that I blew the engine up at and they were fine. In my experiences the only time you have to check and reset the valves a lot is when you run titanium valves, I see this a lot with circle track engines. And to be honest I don't think very many people on this message board will be running Ti valves, and those that are, I'm sure know about this issue. Ti valves are very expensive and require different seats.
I had several people doubt me that this solid roller setup would work when I was planning it and building it. I even had one person say that I didn't know anything about valve trains.
Maybe when I get some extra time and if I can find my notes from building it, I'll post up the exact build in another thread.
The only extra thing I bought was the Hinson rev kit. The reasoning for this wasn't so I could rev it to the moon, it was to better control the lifters and obviously not require the valve springs to control them. When I built this combo I knew it was going to be 7500 to 8000 rpm engine.
The valves I ran were NOT even light weight, they were regular Manley Pro flow valves, and the shitty ebay cheapo rockers as stated earlier weren't exactly light either.
The springs I ran were stock diameter dual springs, nothing special,basically a Pac or Patriot type spring. (I'm not sure exactly what spring was on it cause AI set up the heads for me, I just told them that I wanted the stiffest stock diameter dual spring on it that they could get).
Also, I was using 5/16" pushrods (stock diameter).
This engine never skipped a beat. It pulled hard all the way to the gear change at 7700 rpms.
I put over 100 runs on this combo and never once heard valve float.
However, a downside to this, is that I would probably change valve springs every winter to be safe. This may be too much for some people.
Also, the myth of always having to set the valves is bull **** too. If you constantly have to set the valves there is something wrong. I put about 50 runs on the car this year. I check the valves at the beginning of the year and they were fine, and I checked them again before the event I went to that I blew the engine up at and they were fine. In my experiences the only time you have to check and reset the valves a lot is when you run titanium valves, I see this a lot with circle track engines. And to be honest I don't think very many people on this message board will be running Ti valves, and those that are, I'm sure know about this issue. Ti valves are very expensive and require different seats.
I had several people doubt me that this solid roller setup would work when I was planning it and building it. I even had one person say that I didn't know anything about valve trains.
Maybe when I get some extra time and if I can find my notes from building it, I'll post up the exact build in another thread.
