Tune needed for modified 304 - Can anyone help me?

[383 hatch]

Well, thats a fair point about the revs, however the one i know of that bent the rod actually did it on start up.....Was running fine the night before, started the next morning, knocking noise. We couldn't believe it, took us ages to find it didn't find out what it was untill we tore it down, only to see a bent rod and witness marks on the counterweight. Strange things happen inside engines from time to time.

 

[DeViLisanAnGeL]

hrmmmm. OK, lets hope not
If nothing is revealed via the timing case (which i expect not) heads will be removed to check in there. Nothing shown by that, out she comes. I'm getting pretty quick at this stuff now so doesn't take too long

 

[DeViLisanAnGeL]

Ok so went apeshit on the car last night, in 2 hours managed to strip it back to short motor (block still in the car). Heads, mani, exhaust, timing case etc all off. Can't see anything dodgy, except for cyl no4 where the piston appears to be very clean in contrast to the other pistons in certain areas. These areas are the same shape as the uncut section of the combustion chamber that is level with the deck of the head (dunno how you describe it). There is a small dint mark in the head a couple of mm long and maybe 1mm deep at most in the same spot. The head is also very clean in this spot.

I took photos this morning on the way to work, but have misplaced the camera now... hrmm...

Leads me to think the piston is kissing the head (maybe rod bolt stretch/failure?) Pistons go up and down as they should (der.. ) but they appear to be still in one piece (ie head of the piston has not separated as far as i can tell).

When i get a chance next week (weekend chockers) i will pull the motor out and strip it down. Shouldn't take more than an hour to get it out.

 

[greenfoam]

Cool sounds like not much damage then, Maybe be a buggered bearing/broken rod bolt? both?. Or I'll laugh if the flex plate is loose

 

[DeViLisanAnGeL]

haha
i put ARP covertor and flexplate bolts in when i did the motor, with loctite
so should be sweet

keen to get it fixed so i can get to the all holden day.

 

[Eliminator]

shame it only lasted 2 weeks mate hope you get it sorted, sounds like a woe in the assembly if its **** itself that early in its life.

 

[DeViLisanAnGeL]

Yeah you'd like to think that's not the case, as I double checked everything and was supervised by my old man.

I guess also saying "i wasn't hard on it" is very relative, cos to some people it could be considered i was thrashing it, but to me I didn't feel worried at all haha

 

[DenchY]

try turing the crank both ways and watch no4 piston see if it moves like the others..

when i had bad metal noise and striped it down i had nice shinny pistons and heads (only on 2 pistons) almost sounded like tappets rooted but anyway it was the conrod bearing on the crank got tossed out/ broken.. resulting in piston slap !!

 

[DeViLisanAnGeL]

Yeah we tried the turning both ways, but regardles its coming out tomorrow so will find out for sure!

Sounds similar to what i'm hearing

 

[DeViLisanAnGeL]

OK so stripped the motor down

Spun No.3 Big end pretty hard (one shell was on top of the other), and all other rod and main bearings were rooted (scored and/or flaked the bearing material). Crank has a deep wear shoulder between two of the journals, pretty much unserviceable.

Back to the drawing board...