Tore the engine down today....

[chevytrucks92]

We took the motor out of the car today, found out my problem: broke rod. It broke it right at the base of the rod, just above where it goes on the crank. To explain it, it looked like two rod caps were put on the crank, lol. The rest of the rod was still on the Piston.

Of course it also spun that bearing (#6 cylinder BTW, and thats the 3rd one back on the passenger side of a small block chevy). And that of course did scar the crank a little, but it can be turned I think.

It was also a totally freak thing that caused it to break as well. One of the rod bolts actually came loose! That caused it to spin the bearing, and that's why the car started slowing down (engine was tightening up). It probably did it the last time I was in the finals, and then it really did it when I ran my time trial on Saturday night. We think it finally beat the bearing on out (it was bad too) and this freed the engien back up (remember, it felt like it had its power back when it threw the rod), and that of course let the rod rock back and forth on the crank, and that's why it broke.

Soo, all of this has happened becuase a stupid rod bolt came loose! You think of that now! Evidentally, the shop that built the engine either didn't torque that bolt properly, or just missed it. Oh well. That's part of it I suppose.

I also had a piston get into the #6 intake valve. It bent it. I'm just glad it didnt break it and shove it through the heads. I'm going to take that head tomorrow and get a new valve put in.

I will be ready to race Saturday however. I bought a 355 engine today from one of our friends that also race. I gave him $700 for it. It's got forged flat top pistons and is pretty much brand new. He said he only ran it a few times, and it was set up for nitrous. It's a 4-bolt main block and had a new Crane .568 lift flat tappet cam and lifters, with GM heads with 2.05/1.60 valves and they are ported. However, we put my roller cam from the 406 in the 355 (mine is somewhere around a .650 lift) and my roller lifters, and we're putting my heads (Pro 1, 2.08 or 2.10 intake/1.60 exhaust, and fully ported), which are 10x better then what was on the 355.

The 355 is in the car right now, it just likes one head, the intake (from the old engine as well, ported Victor Jr with 750 cfm ProForm carb), distributor, and the wiring.

So basically, this 355 will be set-up identical to the 406. The only difference in power will be the extra 51 cubic inches. The 355 has the exact cam, lifters, rockers, heads, and intake from the 406.

It will no doubt be slower, but I couldn't tell ya by how much. My 406's best run was 4.403 in the 330, and you could about garuntee it to run 4.45. In fact, the last time I raced, it ran 4.45 three times in a row. I'm figuring that this 355 should run 4.65 at worst. I dont think the hp will be that much difference, but the torque will probably be significantly lower.

Either way, I'll be able to race Saturday night now. This time last night, I wasn't going to be able to race, lol. And I will eventually get my 406 fixed, and when I do, its more then likely getting big dome pistons, and that will take me from running 4.40s in the 330, to 4.30s, and soemtimes 4.20s.

Cliff Notes:
-Rod bolt came loose
-Spun a bearing
-Broke a rod
-Scarred the crank
-Bent a Valve
-Don't think it hurt my 406s block
-Have a flat-top 355 back in the car
-Probably will loose a tenth or two, but will be able to race.

[illegal_eagle187]

how did u get ur rod broken?

[chevytrucks92]

When the rod bolts came loose (two bolts that hold the cap on the rod, which holds the rod on the crank), it allowed the rod bearing to spin. When that happens, the bearing will continue to move between the rod and crank, and it eventually wears the bearing out. That causes a lot of slack and lets the rod move on the crank. When it moves, it will hit the block, and eventually break.

Typically, you can hear them knocking. But its a freak thing when your rod bolts come loose. Thats why the engine showed no signs of going down. It just happened. Those bolts came loose, and the rod started moving on the crank, and that caused the bearing to spin, and then all that slack let the rod hit the block.

I'm lucky it broke where it did, because if it would have broke say in the middle or top of the rod, then it woudl have throwed it through the block instead of the oil pan, and more then likely, instead of just bending a valve (happened becuase when the rod broke, the piston shot up in the cylinder, and hit the intake valve), it would have broke the valve, and then shoved it through the head. If that would have happened, then the entire engine would have been junk.

[nissanfanatic]

Yuck.....

That is pretty strange that the rod bolt just came loose...

Oh well, good luck on getting it back up and running.

[TatII]

it probrably wasn't torqued right. or maybe they were drinking and chatting while building your engine. my professor did that on his hot rod but instead of not torquing the rod tight, the put the rod bearings on backwards and he blew that engine right up.

[chevytrucks92]

Originally Posted by TatII

it probrably wasn't torqued right. or maybe they were drinking and chatting while building your engine. my professor did that on his hot rod but instead of not torquing the rod tight, the put the rod bearings on backwards and he blew that engine right up.

Yeah, I'd say they just didnt have it torqued right. The engine is almost a year old, and it has probably a 100 passes. But still, an engine only a year old shouldn't throw a rod. So there's almost no doubt the bolts weren't torqued properly. And the guy that owns the shop raced this engine in a dirt car of some kind, and had just overhauled it when we got it.

I took the head that was on that side of the engine (the one with the bent valve) to the shop today to get a new valve. I haven't picked it back up yet, but I called the owner and he said he had to replace both #6 valves. Only going to cost me $40. That's not bad at all I dont think. Again, you just don't know how glad I am that it didnt get my heads, lol. I don't think you can get a better set of heads for a small block then what I've got. About the only thing I guess you'd want is for them to be alluminum, and that doesn't make them better (makes them weaker actually), just makes them lighter. But the 50 or 75 pounds I could save with alluminum heads wouldn't make a bit of difference in how the car runs.

Hopefully, this time tomorrow the 355 will be together and ready to run. I'm hoping to hear it by this time tomorrow. Or atleast around this time tomorrow.

[-The Stig-]

Wouldn't the aluminum heads help it run a bit cooler? Help disapate heat faster?

Nnn Shit.

[chevytrucks92]

Well, that's what they say, but this car never gets to 180*. Atleast it didnt with any other engine, lol. And its had alluminum heads on it before. I know I only run 330 ft, but we have to drive back around a really long return road. Its well over a 1/4-mile long, probably closer to a 1/2-mile. And when I get back to the pits, the temp. guage typically reads 170* or so.

Alluminum heads are just so bad about warping. They are MUCH lighter though, lol. You can easily carry an assembled alluminum head in one hand, where as it takes two for a cast head, lol.

Alluminum heads look better, lol.

[-The Stig-]

aluminum blocks look even better.


ever thought about slappin in a LS1? Or, saving up for a LS2 crate?

I read an article that the LS2 with AFR heads, and a fatty bump stick with some headers did 500hp. Prior to tuning it. Thats crank HP by the way.

And the motor wasn't broken in yet. Shave close to 150lbs off the car with just that motor I'd say. That's equivalent to taking a nice hot stack just before the race.

All depending if you had Korean BBQ the night before...

[eps]

Pictures of the rod?

[nissanfanatic]

Most modern engine blocks and heads are aluminum.

With proper torque pattern usage and proper torque stepping, there is no reason for the head to warp under proper usage and temp.

Key word here is proper.lol

What kind of cooling setup do you have? 170 shouldn't really be a problem. I know my car runs at 180 for the msot part and prolly peaks into the 200s on WOT runs.

[Igovert500]

Wow, that is odd. Glad you got it close to running so quickly though. Good luck!

[chevytrucks92]

Originally Posted by RedNeck383

aluminum blocks look even better.


ever thought about slappin in a LS1? Or, saving up for a LS2 crate?

I read an article that the LS2 with AFR heads, and a fatty bump stick with some headers did 500hp. Prior to tuning it. Thats crank HP by the way.

Ahh, not really. I mean LS1s are nice, but man parts for them are ridiculas compared to the old style blocks, lol.

Originally Posted by nissanfanatic

What kind of cooling setup do you have? 170 shouldn't really be a problem. I know my car runs at 180 for the msot part and prolly peaks into the 200s on WOT runs.

I'm not sure what the radiator came out of, but I have 2 electric fans and a high volume water pump driven by an electric motor. No thermostat. The car doesn't run hot at all. I crank it when the two cars in front of me pull onto the track, and after I've done my burnout and staged, its on about 140-150 degrees, and then when I get back to the trailer, its on about 170-180.

And I don't have any pics of the rod. All I have seen of hte rod is just the cap and then the base of the rod. It just looks like two rod caps are bolted together, lol. The rest of the rod is still on the piston.

[Hypsi87]

Originally Posted by chevytrucks92

Soo, all of this has happened becuase a stupid rod bolt came loose! You think of that now! Evidentally, the shop that built the engine either didn't torque that bolt properly, or just missed it. Oh well. That's part of it I suppose.

Just another reason to build your engine instead of a shop.

that sux man but sounds like you are on the right track to a fast recovery.