SBC Bad cam during run-in - Advise needed :)
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SBC Bad cam during run-in - Advise needed :)
Hey everyone,
I have recently had my SBC (approx 1972, 350cui, mild cam, roller rockers, approx 300hp) freshened up, the freshen up included:
- Replacing cam and crank bearings (pistons were left dangling in block as rings and bores were good).
- Replacing Lifters and push rods (Hydraulic flat tappet).
- New valve guides.
- Head and was block skimmed.
- Carby rebuild.
- And new gaskets all round.
Everything else was re-used including: Cam (had cleaned), Crank (Had cleaned), pistons, rings, conrods, roller rockers, distributor although everything was cleaned and checked.
There was also an issue with a threaded head bolt that we had to heli-coil in the block (was #11 bolt in tightening order) nearest cyl #7.
The bolt torqued up perfectly and hasn't traveled loose at all, I simply just thought I'd state it.
The motor had its initial run in procedure done and then traveled approx 17miles so in total has a max of 2 hours run time.
The problem is I have badly worn 2 cam lobes and lifters, the culprits are cly #7 Exhaust and cyl #5 Intake, I find this very weird to be right next to the troubled head bolt... although I checked torque specs again multiple times and it doesn't seem to have traveled at all.
The worn lobes are really quite bad to the point lifter(cyl #7) is dented in so bad it has a hole at the bottom and cyl #5 isn't much better in total both valves have lost about 6-8mm of lift. The motor is currently still in the car as removing it from its current application is an absolute B**** that I'd rather not do AGAIN...
Also the sump to timing cover gasket got damaged while removing the timing chain cover.
My main questions are:
- How far do I need to drop the sump to replace the sump to timing chain cover gasket? and can I reuse the other sump gaskets or do I need to replace all again.
- Should I tear the whole motor down to clean it up and replace all the bearings again (I REALLY don't want to!) or could I get away with running some oil through it to clean it up or something?
- Is there any pointers or advise that could be given to help avoiding damaging anything again?
Ultimately I'd like to keep the motor in the car, clean it all up replace the cam and ALL the lifters and pushrods, Obviously I'd replace all the gaskets of things I have removed: intake mani, carb, fuel pump, water pump, timing chain cover and sump to timing cover. would anyone recommend against that?
Any help is greatly appreciated.
I have recently had my SBC (approx 1972, 350cui, mild cam, roller rockers, approx 300hp) freshened up, the freshen up included:
- Replacing cam and crank bearings (pistons were left dangling in block as rings and bores were good).
- Replacing Lifters and push rods (Hydraulic flat tappet).
- New valve guides.
- Head and was block skimmed.
- Carby rebuild.
- And new gaskets all round.
Everything else was re-used including: Cam (had cleaned), Crank (Had cleaned), pistons, rings, conrods, roller rockers, distributor although everything was cleaned and checked.
There was also an issue with a threaded head bolt that we had to heli-coil in the block (was #11 bolt in tightening order) nearest cyl #7.
The bolt torqued up perfectly and hasn't traveled loose at all, I simply just thought I'd state it.
The motor had its initial run in procedure done and then traveled approx 17miles so in total has a max of 2 hours run time.
The problem is I have badly worn 2 cam lobes and lifters, the culprits are cly #7 Exhaust and cyl #5 Intake, I find this very weird to be right next to the troubled head bolt... although I checked torque specs again multiple times and it doesn't seem to have traveled at all.
The worn lobes are really quite bad to the point lifter(cyl #7) is dented in so bad it has a hole at the bottom and cyl #5 isn't much better in total both valves have lost about 6-8mm of lift. The motor is currently still in the car as removing it from its current application is an absolute B**** that I'd rather not do AGAIN...
Also the sump to timing cover gasket got damaged while removing the timing chain cover.
My main questions are:
- How far do I need to drop the sump to replace the sump to timing chain cover gasket? and can I reuse the other sump gaskets or do I need to replace all again.
- Should I tear the whole motor down to clean it up and replace all the bearings again (I REALLY don't want to!) or could I get away with running some oil through it to clean it up or something?
- Is there any pointers or advise that could be given to help avoiding damaging anything again?
Ultimately I'd like to keep the motor in the car, clean it all up replace the cam and ALL the lifters and pushrods, Obviously I'd replace all the gaskets of things I have removed: intake mani, carb, fuel pump, water pump, timing chain cover and sump to timing cover. would anyone recommend against that?
Any help is greatly appreciated.