Hi Folks, was on a long run yesterday on the freeway, dropped into fifth to pass some car up a slight hill onto boost about 4500rpm 2/3 throttle heard a pop/bang brief cloud of black smoke from the RHS same side as the noise, so I backed right off, all gauges OK, no lights. Thought maybe a backfire...

Cruised into the next town 5 minutes or so slow driving as I pulled up at the lights, heard a tapping sound from the rear, pulled over had a listen from inside the engine bay and sounds like a rod knock from the RHS.

So time for new rods and bearings I guess and a few other things whilst in there.

Running new Tial Alpha 28s, 60lbs inj, GIAC 700 tune.

Car is being trucked back to my place next few days, so I am just trying to think of next steps, any suggestions welcome.

rgds
mike

 

I'm pretty sure a bent rod would make more than just a tapping noise. To me it sounds cam or valve related

 

With the GT28's they are known for bending rods and a guy on here had the same thing one rod just touched the casing somewhere till the motor warmed up. Ill try post his pics and this was still running fine and it was still quick

 

i just disassembled a motor from another member who thought the IMS bearing was going it had a tick that followed the rpms. it was a slightly bent rod touching the case as it Rotated.

it happens very easy.

 

4500rpm in 5th - you were moving. Sorry to hear about your engine.

Out of curiosity how much boost were you running and how much when it had troubles?

 

Normally its high load at low revs bends rods

 

So too much boost/torque for that RPM? Detonation can cause that too amongst other things. So the rods are a week point with this motor then? Are the 60lb injectors maxed out with that tune/boost?

Anyways that sucks man!!! Hopefully you have it back up and running soon!!
Scot

 

wow that sux

 

gt700 runs high boost 1.4bar +- so maybe bad fuel or lean condition etc...! i run 2bar spike with meth and car run 2.3sec 60-100 with a28s stock engine !no knocking here.
i wish you the best with your future built*

 

A28's at 1.4 bar are doing what about 620-650 lbs-ft (700+ at the crank talk) equivalent, plenty to bend our soft rods

 

Soft rods?!?! bummer. Good to know though. Been meaning to ask...what are the limits of these engines realistically? Is 600ft-lb torque is about all the bottom end can handle? What about a setup that has a later power curve?

 

A28's kill the most stock engines... And I just put them on my new to me stock engine turbo for DD duty.. Built the Engine and never look back. With A28's and a built engine you are hard pressed to find a better street car.

 

Tim, what rods/pistons combo did you go with?

 

On my daily? It is a un opened turbo engine... for now. My red 996 makes 1300 wheel hp on stock pistons (modded) and Carrillo rods.

 

hopefully its just bent rod touching the casing, it sounds worse cold. Will listen more with a stethoscope when I get her back home.

LQQK answer to your question I am running a 98 pump tune at the moment at 1.4 bar.