Last May I broke a piston skirt on my 250, and I started a thread on how I should proceed. My block, which was scored, was already out to 60 thou and I asked your advice as to whether or not to go to 80 thou. The concensus was to go for another block as 80 thou was too much and would cause over heating problems when towing my trailer.
This is an update to let you know that I went for the standard bore block that my builder fortunately had under one of his benches. I had it bored 30 thou over and balanced, installed TRW pistons and Hastings rings and moved over my crank, cam, timing gears and heavy duty oil pump. Since the previous owner had already removed the intake port bosses in the head, I felt it was a good time to install a set of lumps from Larry to see what difference they would make in the performance. I just finished putting the car back together today. I'll let you know my feelings on the lumps over the next few weeks as I gradually begin the break in process.
Al

Sounds good, did you deck the block close to zero?

The lumps should help out.
What intake manifold/carb are you using?

Have fun breaking it in !

MBHD

Thanks MBHD.
Didn't deck the block.
Running a water heated Offy and a 500cfm Edelbrock with home made headers.
It's been a long road. Hopefully there is some summer left that I can enjoy driving.
Al

al,
what are the specs on your cam? do you know what final compression ratio you ended up with? good luck with the brealin. i like to run a jug of GM EOS in with the first run of a engine. tom

Hi Tom
Don't know the specs on the cam. It's an old Shadbolt RV cam. I didn't change it as it was working well for me and seemed to have good low and mid range pulling power.
I'm also not sure of the final compression ratio. The head has not been milled as far as I know, and the TRW's have a very slight dish to them.
Al

Still breaking in my motor. Got about 400 miles on it now. I seem to have a ticking noise coming from the lower end. It sounds like a rocker arm slightly out of adjustment but it is coming from the vicinity of the oil pan.
Any ideas?
Al

Rod Knock?


Only thing I know that sounds like that and would come from there.

Ticking or knocking?

Consistent or just when it feels like it?

Have you 'scoped the engine?

mechanical fuel pump?

It's more a loud tick than a knock.It is consistant, but only on the idle. Seems to disappear as the rpm's go up. I have an electric fuel pump.
Not sure what you mean by scope.
Al

Mechanic's stethoscope-it's like a doctor's but with a rod at the end instead of a cup. It helps with pin pointing where a noise is coming from. You touch it to spots on the engine and listen.

Them Stethoscope things are less than $10 at O'Reilly's.