All things considered equally what component would be most likely to give first on a stock big block that was slowly raised in rpms until it detonated? Pushrod bending? Connecting Rod shattering? Piston coming apart? Cam or Main bearing meltdown? Just curious.
half of the (dozen or so) 455 cars i have ever bought have had blown head gaskets due to cooling problems ...the other half (with the exception of one from my current 74 vert that ran fine and i sold to FREEEDSTER), ended up dying from oil pump weaknesses.
I wonder what would die first if cooling and oiling wernt an issue. Maybe the structural tolerances are close enough that its impossible to tell.
Are you in neutral? Then probably the con rods (unless it drops a valve). However if the engine is under load, then you'll have other reasons. Is this an engine that fails because you are putting too much HP in it (like with a supercharger)? Or, just over-revving it? Different methods will cause different modes of failure. -Bob Cunningham
I had a 430 with a stock bottom end and valve train (except for the cam) that I kinda-sorta reved over 7000 RPM in neutral (once or twice!) before I knew better. I decided to quit while I was ahead and the engine lasted for a good long time after that, however when the engine was pulled apart one of the front main bolts was broken in two! I don't know when it happened but I'm sure reving it over 7000 didn't help!
Interesting! Im just doing some 'for fun' research on metal technologies like HY-80 and Titanium for valvetrain & other components that are likely to fail under stress. The ideal method would seem to be replacing components one at a time and testing until failure then replacing what failed with something stronger until a satisfactory overall strength was reached. Sure it would be expensive and time consuming but would make for an awesome writeup. I love technology. Things like; peltier coil airconditioning, reverse port blowing & intelligent programmable suspensions keep me geeking hard for months. Ive got a picture of (I think) a reverse port blown nailhead somewhere that is an amazing sight to behold. Very out there.
I just pulled my engine completely apart today and can add to this. My #4 piston is in several pieces, but the rod, crankshaft and heads are OK. It appears the rod bearing ( Upper half) "spun." How it became dislodged from the rod is a guess as the bearing itself looked good, torque specs were still OK, and oil pressure was never a problem. I would guess the piston broke from contacted the head several times. The cylinder wall is a bit damaged. Can it be sleeved? Hope to hear from some of you on this one. Russ
After spending the day at Rod Hendrickson's house, I can tell you that no part is safe if you start racing it! Hes got enough junk parts laying around to fill a pickup truck. If you are going to beat on it, you have to overbuild it!
Depends if it's detonating and under load and how long. The oil system is irrelevant when just revving it once in neutral. Oil will be on the parts long enough for that even if the pressure were low. I have gone to 6900 down track with stock crank, rods, cast pistons....and nothing broke.......except the block. :Brow: Half of a bearing saddle came out with the main cap! Bruce
Embarassing story... When I first bought my GS I knew next to nothing about cars (except which ones were good ones :TU: ) My bro-in-law wanted to see the tach fly up, so I just nailed it to the floor and held it there. I assumed that the engine would just go to redline and stay there. ou: Valves floated and the engine died, and it took several tries to restart it. 7 and 8 rod bearings lasted about another two years...
Brian, Brian, Brian, those are not junk parts. Those are hand me downs from the Skyhawk for that lovely 65 Skylark sitting in the drive (my toy at the track :Brow: ) A pick up trucks worth??? I can tell you were not around to help us move last fall, He still has stuff out at his mom's farm!! Why do you think he is building an 8 car garage ou: Rod seems to find the weakest link in the car pretty easy. Just up grade anything in the car and the next problem will jump right out at you. The trans is the weakest link now. Next will be the block, but I didn't say that.
Once the proper upgrades are done, the weakest thing seems to be the competition's knees:laugh: The last 455 I put together, I used the grooved cam bearings and made sure my main/rod bearing clearances were dead on. The car was built as a mild street car, so no huge cam and rev limiter in the MSD set at 6k RPM. Shift point was 5700, and the car ran a 12.38 with a 3.73 rear and 2400 stall. Vehicle weight was 3890 with driver. No reliability issues, and the owner still races the car from what I've heard. Spend your money/time getting everything set how it's supposed to be, and you'll be fine.
I personally think that the weakest link is the loose nut behind the wheel.ou: That is the one that always gives me the most problems.:3gears:
This is probably the most common problem. Most failures can usually be traced back to abuse/misuse or an error made during assembly. Weakest link...Human error!!
