H-I-J '76 Nova re-fit.

[Dissident]

Todd,
Being a data kind of guy, I ran some quickie calculations for the potential flow (internal leaks) of the EDM lifters and the groove thing in the lifter bores. I used 50psi as that is the pressure number you mentioned.The EDM lifters will flow approx 0.0371gpm (each) at 50psi. The grooves in the lifter bores will flow approx 0.264gpm (each) at 50psi. Doesn't sound like much until you toss in each number times the 16 leak paths. Total flow at 50psi = 4.8176gpm! WOW.

At that rate of flow, 5qts (1.25gal) will cycle very quickly. The grooves themselves go through 4.224gpm so I suspect that is the major offender and caused the earlier ugly bearings. Seems like the grooves need to be rendered useless, but I suspect that your engine shop guys have already suggested that.


I realize that I might be full of soup in this assessment, but I think it is very close to the correct analysis.



Best of luck solving the problem.



Regards,
HB2
Dissident

[Alan Nyhus]

Originally Posted by Dissident

Todd,
Being a data kind of guy, I ran some quickie calculations for the potential flow (internal leaks) of the EDM lifters and the groove thing in the lifter bores. I used 50psi as that is the pressure number you mentioned.The EDM lifters will flow approx 0.0371gpm (each) at 50psi. The grooves in the lifter bores will flow approx 0.264gpm (each) at 50psi. Doesn't sound like much until you toss in each number times the 16 leak paths. Total flow at 50psi = 4.8176gpm! WOW.

At that rate of flow, 5qts (1.25gal) will cycle very quickly. The grooves themselves go through 4.224gpm so I suspect that is the major offender and caused the earlier ugly bearings.

Regards,HB2Dissident

Actually, I think your figures are pretty close. Lifter bore clearance is also a component. Todd mentioned that one of the lifter bores had two grooves in it. -Al

[Rich Biebel]

The correct solution to me, is one of two choices. Machine the lifter bores for bronze sleeves to eliminate the grooves and use the direct lube lifters. OR....Use the block as is and buy different lifters without the holes. Either option is gonna cost a good bit. Using restrictors is worth a try at this point.

[Pat6868]

Back to time proven basics is the way I would go, and it wont cost that much.

[Hacksaw]

Is there some way you can fill the slots in the lifter bores other than using bronze bushings? With todays chemicals, I would think there must be something that should work.

[FED 387]

I know you don't want to hear this but maybe its time to get another block and start over unless you want to do bronze bushings---not sure what your guy will charge you but doing 16 lifter bores in labor & the cost of the bushings can get kind of expensive---you will still have your rotating stuff and heads etc so all you are really doing is getting to the point where you have a straight good block to work from---you want to do any tricks you can always do that but there has to be a ton of good SBC blocks you can choose from and move forward on your project---as somebody suggested go back to the basics and go on from there---FED 387

[Pat6868]

That engine will live grooved bores and all. Pay attention to lifter bore diameter, push rod hole size, oil drain back, oil viscosity. Good quality solid lifters (no hole), quality standard volume, standard pressure pump. Good starter or back up engine. Put it together and have fun. Not gonna cost that much.

[Jim Hanig]

Just a though ,make sure the screw in plugs in the front are not in to deep, Center one .

[Nmbr1GMfan]

Originally Posted by Dissident

Todd,
Being a data kind of guy, I ran some quickie calculations for the potential flow (internal leaks) of the EDM lifters and the groove thing in the lifter bores. I used 50psi as that is the pressure number you mentioned.The EDM lifters will flow approx 0.0371gpm (each) at 50psi. The grooves in the lifter bores will flow approx 0.264gpm (each) at 50psi. Doesn't sound like much until you toss in each number times the 16 leak paths. Total flow at 50psi = 4.8176gpm! WOW.

At that rate of flow, 5qts (1.25gal) will cycle very quickly. The grooves themselves go through 4.224gpm so I suspect that is the major offender and caused the earlier ugly bearings. Seems like the grooves need to be rendered useless, but I suspect that your engine shop guys have already suggested that.


I realize that I might be full of soup in this assessment, but I think it is very close to the correct analysis.



Best of luck solving the problem.



Regards,
HB2
Dissident

This is an eye opener!

[Nmbr1GMfan]

Originally Posted by FED 387

I know you don't want to hear this but maybe its time to get another block and start over unless you want to do bronze bushings---not sure what your guy will charge you but doing 16 lifter bores in labor & the cost of the bushings can get kind of expensive---you will still have your rotating stuff and heads etc so all you are really doing is getting to the point where you have a straight good block to work from---you want to do any tricks you can always do that but there has to be a ton of good SBC blocks you can choose from and move forward on your project---as somebody suggested go back to the basics and go on from there---FED 387

The pistons and this block are pretty much junk without each other, so if I have to get a block I have to buy pistons and vice versa. IMO, It will be fine when I get the oiling straight, it ran before. I just need to make this reliable so I have a spare. When it runs I'll start with a Dart block and all new internals.