[spectramitch]

Originally Posted by mgarblik

By "drop the caps", I assume that means cutting the caps? After they were done doing that, did they line hone the housing bores to make them round again and remove any taper from cutting the caps? There is a little more to finishing this up than just cutting caps. Your installation work of the caps looks very nice, just make sure it is finished 100%. I don't like to run a block without line honing. I like to finish the housing bores on a 3" main block at 3.1883-3.1884. I like 80% of the bore diameter to gauge at +-.0001 of that dimension with some growth toward the parting line. I like all 5 mains +-.0001 in taper. If you have those dimensions, your King bearings will have around..0028"-.0032 oil clearance. Looking really nice so far.

They cut the bottom of the caps and said it did not need the line hone. There is growth at the PL somewhere around .001 a side. I believe there is slight taper the worst being .0003 from front to back of a journal. I might find another shop to run a line hone through it.

[mgarblik]

Originally Posted by spectramitch

They cut the bottom of the caps and said it did not need the line hone. There is growth at the PL somewhere around .001 a side. I believe there is slight taper the worst being .0003 from front to back of a journal. I might find another shop to run a line hone through it.

I wish you were closer. I am in Dayton, OH. It probably needs 1 full pass. Then flip block and make 1 half to full pass and it would be done and just right.

[spectramitch]

How much extra horizontal clearance towards the Parting line is typical? My thrust journal has .005 on the parting line

[mgarblik]

I have seen as much as .002" without issue. Rule of thumb is 80% of the diameter should be within tolerance. The more times you cut caps and line hone, the lesser of the full diameter can be restored at the parting line. Some racing blocks may be line honed 8-10 times after multiple bearing failures. They can be a challenge. Worked with a student last night on a Toyota Supra in-line 6. 7 fairly large main housing bores. 1000 HP engine. Really tough to get all 7 right on the money. The factory didn't even try. They supplied 8 different main bearing sizes, each .0002" different. This engine had 5 different sizes in the same engine. Once rebuilt, all the bearings are the same size. Tough job. Hard to believe a stock bottom end can take 30+ lbs. of boost.

[Jack Gifford]

I've relied on bearing inserts to provide the necessary extra clearance at the parting line. Incorrect?

[mgarblik]

Originally Posted by Jack Gifford

I've relied on bearing inserts to provide the necessary extra clearance at the parting line. Incorrect?

It's certainly important to have that clearance built-into the bearings as well. OE, the main housing bores are line bored and not honed. So in theory, they are perfectly round. The clearance built into the bearing shells would be necessary to prevent pinching the bearings at the parting line under heavy load. But there is no way to restore a 100% round housing bore by cutting caps and line honing. You can get close with really careful set-up. Now if replacing all the caps with new and indexing off the block saddle, you could line bore a perfect hole again in theory. My "guess" is this is how the 80% rule came into being.

[spectramitch]

Here is a layout I made up of the Main Bore Diameters. This is without bearing shells. I measured vertical Bore (3.188-3.189) and recorded dimension. Then I gauged 45° from there and measured 'runout'. I know 3 and 5 are a couple tenths under book spec but I feel that is the least of my issues. I think the block may have been jacked up from the start when I first bought it. I'm worried about excessive oil clearance at the parting line causing low oil pressure to the rods. I need some second opinions on what to do here.

[hurryinhoosier62]

Originally Posted by spectramitch

Here is a layout I made up of the Main Bore Diameters. This is without bearing shells. I measured vertical Bore (3.188-3.189) and recorded dimension. Then I gauged 45° from there and measured 'runout'. I know 3 and 5 are a couple tenths under book spec but I feel that is the least of my issues. I think the block may have been jacked up from the start when I first bought it. I'm worried about excessive oil clearance at the parting line causing low oil pressure to the rods. I need some second opinions on what to do here.

I would be align boring the main saddles. There is too much variance in the measurements within each saddle. As a rule, I attempt to keep the main saddle size at 3.1880-3.1885.

[Jack Gifford]

Originally Posted by spectramitch

... I'm worried about excessive oil clearance at the parting line causing low oil pressure to the rods...

I don't believe the larger parting line dimensions of the bores will cause excessive oil clearances. I can't picture the bearings flexing measurably over that short distance (ever tried bending an insert?). The most oversize dimension (#4) is where the U-shaped thrust bearing resides- and it ain't gonna flex at all.

[mgarblik]

Personally, I could align hone that block and make it quite a bit better. I don't have the capability to line bore the front and rear cap. I only have a line boring attachment for my Sunnen line hone. It sets up on the rear main and can only bore the center 3. If it was in my shop, I would cut all the caps .003 and line hone the 5 bores +-.0001 and +- .0001 for taper. IMO, your parting line oversize is not an issue. The situation you have now is really this: Will the block work as is? Yes IMO. Is it "blueprint quality"? No. You have put allot of time,effort and money into properly installing billet splayed caps. Now IMO, you need a race shop capable of finishing the job with the same care and attention to detail you have put in yourself. You need a race shop that cares about getting it "to specs.", not just hitting a tolerance range. Hopefully, someone can recommend a shop that cares about getting it more than just "good enough for an old Pontiac". That's the issue you often run into.

[hurryinhoosier62]

Originally Posted by mgarblik

Personally, I could align hone that block and make it quite a bit better. I don't have the capability to line bore the front and rear cap. I only have a line boring attachment for my Sunnen line hone. It sets up on the rear main and can only bore the center 3. If it was in my shop, I would cut all the caps .003 and line hone the 5 bores +-.0001 and +- .0001 for taper. IMO, your parting line oversize is not an issue. The situation you have now is really this: Will the block work as is? Yes IMO. Is it "blueprint quality"? No. You have put allot of time,effort and money into properly installing billet splayed caps. Now IMO, you need a race shop capable of finishing the job with the same care and attention to detail you have put in yourself. You need a race shop that cares about getting it "to specs.", not just hitting a tolerance range. Hopefully, someone can recommend a shop that cares about getting it more than just "good enough for an old Pontiac". That's the issue you often run into.

Mike, that is the reason I suggested align boring the block. Very few engine machinists are going to take the time to put the effort you do into align honing a main saddle. It makes me wish I could go back to machining engine blocks and components, but I believe my wife and my doc would have me committed.

[spectramitch]

I took the block to Holbrook Racing in Livonia MI and they got it straightened out for me in less that 24 Hours. Looks good with cross hatch (there was none before) and is much rounder. I feel a lot better about it and can sleep at night. Thanks Tom V. for the recommendation.

[Tom Vaught]

Glad to help. I have known the people at Holbrook Racing in Livonia Michigan for 45+ years.
Was a Father and Son operation. Son runs the business the last 20 years.

Glad I could help out on your project.

Tom V.

Chris does excellent dyno testing too.

[mgarblik]

That looks good. Glad you got it all fixed up. I much prefer line honing to boring as a final step. That's why we hone cylinders rather than just bore and go. Much more control of tiny amount of stock removal. I also like that I can see a gentle clean-up of the pan rail as well as the cap registers. Looks like a good job.

[spectramitch]

With the King Hp Bearings my clearances are (1).0031 (2).0028 (3).0029 (4) .0033 with X UPPER ONLY (5) .0035 My crank is on the Low end of Dia @ 2.9991-2.9993 I have a Butler Pro 60 psi pump that I'll probably shim to 70 or whatever. I want good oil pressure at idle as itll see the street, but I want to stay away from 50wt oil. Do you think I should mix some more X bearings in to loosen it up?

[mgarblik]

Numbers look good to me. 10W-30 oil should give you about 90-100 PSI cold start, dropping to 25 PSI or so hot idle. Normal driving PSI should be at bypass pressure. Rod oil clearance and side clearance may change this slightly.