Discussion
Never sure whether to put updates in here since the car is a [retired] Tuscan Challenge racer, or in the general section as I don't do the 'Challange'. Hopefully get it out in the SuperLap series at Knockhill if I can get it 'debugged' in time.
Anyway, I'll put the techie stuff in here. The previous small-block Chevrolet grenaded itself at a track day at Oulton Park last year (in fact the 3rd major engine failure on a small-block, so enough was enough). The change to the LS7 took longer than I'd hoped (and cost waaaay more
) but I got it running under its own steam again today. Still some bits and pieces to do, and the engine's rough as old boots on the first spin up the road but at least its back down to 'development' rather than 'building'.
Physically getting the engine in wasn't too much of a problem, although I did have to cut chunks off the block. But there does seem less space around the motor, and the SBC was on a wet sump and a carb. A bit of challenge to get the dry sump pump in and the dry sump tank while keeping it still a 2-seater. Alternator was another problem, as was the exhausts, as was the fueling...hell it was one problem after another but it runs now
So the motor is an LS7 block with all-steel internals and worked-on LS3 heads and a hot cam. Bench dyno'd at 630hp, but presumably making less in the car. Canems ECU, Aeromotive fuel pump, filters, rails etc. 'Standard' internal oil pump for pressure and Razor scavenge pump. Tilton clutch and release bearing and I kept the TKO600 from before. Home made brackets galore and more braided hose and AN fittings than you can shake a stick at.
If I can get it MOTd and taxed again next week I can get some miles on it for a proper shakedown (the advantage of having it road-registered).
Anyway, I'll put the techie stuff in here. The previous small-block Chevrolet grenaded itself at a track day at Oulton Park last year (in fact the 3rd major engine failure on a small-block, so enough was enough). The change to the LS7 took longer than I'd hoped (and cost waaaay more
) but I got it running under its own steam again today. Still some bits and pieces to do, and the engine's rough as old boots on the first spin up the road but at least its back down to 'development' rather than 'building'.Physically getting the engine in wasn't too much of a problem, although I did have to cut chunks off the block. But there does seem less space around the motor, and the SBC was on a wet sump and a carb. A bit of challenge to get the dry sump pump in and the dry sump tank while keeping it still a 2-seater. Alternator was another problem, as was the exhausts, as was the fueling...hell it was one problem after another but it runs now
So the motor is an LS7 block with all-steel internals and worked-on LS3 heads and a hot cam. Bench dyno'd at 630hp, but presumably making less in the car. Canems ECU, Aeromotive fuel pump, filters, rails etc. 'Standard' internal oil pump for pressure and Razor scavenge pump. Tilton clutch and release bearing and I kept the TKO600 from before. Home made brackets galore and more braided hose and AN fittings than you can shake a stick at.
If I can get it MOTd and taxed again next week I can get some miles on it for a proper shakedown (the advantage of having it road-registered).
.Lovely
Someone was going to do it one day!
Best practice up north, then when you have it ready...race it in the challenge!
Incidentally, I'd protect that filter from wheel debris and water.
And did you find out what happened to the last one? Was it oil starvation (wet sump)
Well done again
Andy
Someone was going to do it one day!
Best practice up north, then when you have it ready...race it in the challenge!
Incidentally, I'd protect that filter from wheel debris and water.
And did you find out what happened to the last one? Was it oil starvation (wet sump)
Well done again
Andy
Guillotine said:
Best practice up north, then when you have it ready...race it in the challenge!
Yea, but given the interest in the past for any series to come up and do even a single round at Knockhill because of the distance, I'd have the same distance and some for every round in the South. Oulton Park is a 550 mile round trip for me, and lots of folks in the South consider it a decent drive North!Guillotine said:
Incidentally, I'd protect that filter from wheel debris and water.
On the list of things to do, plus protect the oil cooler hoses on the other side. And the eagle-eyed will notice there's no oil breather tank yet. I took the right hand oil-cooler out (I actually took both out as they had seen better days, and just replaced with one). I was hoping to run with just one with the LS and use the opening on the right to give a cold air supply. I'll definitely protect it from the hot air off the radiator and debris off the wheel. I'm in 2 minds about giving maximum cold air and ducting direct from the front, but that will bring in water and all sorts; or having it above the airflow so there's cold air in the area but rain etc would go underneath.
I won't do too much work on that side yet until I know it can run with just the one cooler, as I may have to re-plumb the intake.
Guillotine said:
And did you find out what happened to the last one? Was it oil starvation (wet sump)
The SBC had a monster winged sump and the logs never showed any oiling problems. Looking at all the damage I can work out what must have happened first (as everything else is consequential), but no idea why. The block and bore were wrecked when the rod went through the side. But the rod was intact (but bent) so it had to go walk-about when the piston came apart. The remaining piston fragments and head have 'cuts' in the crown matching the edge of a valve so there had to be a valve-head side-on in the bore, and there is a valve stem still in the guide...and no valve head so clearly the head came off the valve.
But there's also a broken valve spring on that valve and a head/valve contact wouldn't break the spring, but a broken spring would have dropped the valve; gets whacked by the piston and takes valve head off. The only mystery is why the spring broke. It had Jessel shaft-mount rockers so really precise valve control. And the data logs and video confirm it was a cooling down lap at constant 3000rpm with good pressures and temperatures. I guess just fatigue in the valve spring.
It may be the other way around
My investigations for Chevy have found a major failing in the pistons
They chip at the crown or
Separate around the gudgeon pin hitting the valves and possibly inyour case braking the valve off?
Anyway, the forged stuff will cure that as I believe that even the 7 uses hyper pistons... Yuk.
Goodluck with it mate, and as for the geography thing, I drove upto Glasgow last week and I know just where you are coming from. I reckon Spa is closer!!!
;-)
My investigations for Chevy have found a major failing in the pistons
They chip at the crown or
Separate around the gudgeon pin hitting the valves and possibly inyour case braking the valve off?
Anyway, the forged stuff will cure that as I believe that even the 7 uses hyper pistons... Yuk.
Goodluck with it mate, and as for the geography thing, I drove upto Glasgow last week and I know just where you are coming from. I reckon Spa is closer!!!
;-)
Edited by Guillotine on Sunday 5th May 11:20
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