[hurryinhoosier62]

Originally Posted by chiefbigb

I am a Cummins and caterpillar master machinist. Worked for dealers and oems since 1990. Mostly did deck repair at remote locations. Not allot gets fixed anymore just swing engines in long block form. I do more wiring and emissions work these days. Still play with the Pontiac engines. There are a couple in progress similar to what Tim is working on out there now.

Machined a few N14s back in the day along with a multitude of 4Bs, 6Bs and 6Cs. Machined way too many 1100/3208s and 3116s and 3126s. We stayed out of the CAT market; hard to compete with the OEM you purchase your parts from.

[Tim Corcoran]

My engine has moved from the line hone station to to boring machine. Boring operation is starting soon.

[Tim Corcoran]

More pictures of boring the cylinders for my block. The sonic test showed a little thin for going .060 over on one bank on the thrust side. Based on one of your suggestions to "jerk the bore" my machinist is doing just that. While going from a standard bore to .060 over he is able to move that bank over about .025 to give me more material on the thrust wall. That plus the hard block I put in should give me a solid cylinder block. Next step is honing to final size..

[joes455]

What is considered a thin bore Tom?,I've got my 71 400 at 4.210 hard block

[Dragncar]

Originally Posted by Tim Corcoran

More pictures of boring the cylinders for my block. The sonic test showed a little thin for going .060 over on one bank on the thrust side. Based on one of your suggestions to "jerk the bore" my machinist is doing just that. While going from a standard bore to .060 over he is able to move that bank over about .025 to give me more material on the thrust wall. That plus the hard block I put in should give me a solid cylinder block. Next step is honing to final size..

Why this push to go to a .060 over final bore, the LAST ?
When I put all the money into my 400 block to install splayed billet caps, the intention from the start was to go .030 over so I could have one more bore in mt block.
That is why I insisted on a block with a good std bore.
Just get some .030 pistons and be done with it IMO.
Better yet, jerk the bore with the .030 pistons to insure you have another bore in it.
Machining that block was not cheap, might as well get your full use out of it.
The difference in power between a .030 bore and a .060 has got to be pretty small.

[HWYSTR455]

I don't think it's actually a 'push' to go .060 over, but that's what that particular block will take to square up the block. (bore / crank relation )



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[Tim Corcoran]

I jerked the bore on one bank to give me more thickness on the thrust side plus put plenty of hard block to stiffen things up. I think it will be plenty strong, time will tell.

[HWYSTR455]

Ah, now I see, thanks for the correction. I had to go bigger a couple times to correct the alignment, maybe that's why I was focused in that direction.

I went to .060 over twice on purpose specifically to increase displacement. But the payoff was negligible. Once for getting bore & stroke the same. (but that's a different 'square' definition)


.

[Stan Weiss]

Originally Posted by Tim Corcoran

I jerked the bore on one bank to give me more thickness on the thrust side plus put plenty of hard block to stiffen things up. I think it will be plenty strong, time will tell.

So if I correctly understand what was done. Now where the bore cylinder center line from each bank meet at 90 degrees is no long at the crank main journal center line.

Stan

[HWYSTR455]

Way I'm thinking is #6 & #7 are more forward towards the front of the block, to allow for as much meat as possible to stabilize the #4 main journal structure.

You want the 90 degree angle to the crank centerline as perfect as possible. Sometimes you have to bore a cyl slightly more to correct that relationship. And that's what I was originally thinking of as well.

.

[Tim Corcoran]

Originally Posted by Stan Weiss

So if I correctly understand what was done. Now where the bore cylinder center line from each bank meet at 90 degrees is no long at the crank main journal center line.

Stan

Stan
According to my machinist, the bank that is being moved not only gives me more material on the thrust side but it is correcting the factory position of the bores in relation to the crank centerline. Due to core shift and mass production what Pontiac did was good enough for a production vehicle. My machinist is blueprinting my block and correcting the bore position. Just so happens this gives my more material on the thrust side. Many have suggested I should of went with a .030 overbore and maybe they are correct. I am not sure if the .030 makes much difference one way or the other. Based on the sonic test by moving the bores to the correct position and going .060 over I will have about the same material on the thrust side as if I just bored it .030 over.

[Stan Weiss]

Originally Posted by Tim Corcoran

Stan
According to my machinist, the bank that is being moved not only gives me more material on the thrust side but it is correcting the factory position of the bores in relation to the crank centerline. Due to core shift and mass production what Pontiac did was good enough for a production vehicle. My machinist is blueprinting my block and correcting the bore position. Just so happens this gives my more material on the thrust side. Many have suggested I should of went with a .030 overbore and maybe they are correct. I am not sure if the .030 makes much difference one way or the other. Based on the sonic test by moving the bores to the correct position and going .060 over I will have about the same material on the thrust side as if I just bored it .030 over.

Tim,
That is great how that all worked out. Since he is blueprinting your block, is he also doing your crank? The rod journal indexing is normally off a small amount.

Stan

[Tim Corcoran]

Originally Posted by Stan Weiss

Tim,
That is great how that all worked out. Since he is blueprinting your block, is he also doing your crank? The rod journal indexing is normally off a small amount.

Stan

The crank is a Scat Forged 4.25 stroke I got from Butler in a balanced stroker kit. I asked the machinist to check the crank for journal size, taper and out of round condition. He was happy with the crank. I think I will use the crank as is. My machinist does not have a crank grinder. Not sure there is a shop that can grind cranks in Raleigh North Carolina.

[HWYSTR455]

Inside Pro is in Mooresville, not sure what the wait list is though.

Honestly, Butler does check them, but no indexing unless it's 'bad' out of the box. If you get one that's like .010/.010, you know it's been corrected. Usually they will info people if it gets turned.

.

[hurryinhoosier62]

Originally Posted by Stan Weiss

Tim,
That is great how that all worked out. Since he is blueprinting your block, is he also doing your crank? The rod journal indexing is normally off a small amount.

Stan

“A small amount”? You’re lucky if you only have to go .020 under to index a crank to exactly 90 degrees. I’ve seen many that had to go .030 under. It is one of the reasons why my crank grinder only recommends indexing for full race engines ( NHRA Stock and Super Stock).

[Tim Corcoran]

I got the block back from the machine shop. I am sure many of you know how exciting that can be if you have been waiting a long time. After installing the cam bearings while at the machinist we checked the fitting of the cam and it was a little tight. It was the rear journal and it took a few minutes to find where it was rubbing and remove a little babbit and got her spinning just fine. I removed all the plugs and super cleaned the block before it went to the machine shop. Same thing again after all machining was done. Took it home and installed the plugs in the rear of the block before putting it on the engine stand. While installing the plug that goes in behind the cam make sure it doesn't go too deep you don't want the cam hitting it as the cam is located by retainer on the front. Don't forget the threaded plug that goes inside the block that is behind the small plug on the drivers side. Some recommend drilling the plug .040 before installing the plug or you can purchase a pre-drilled plug from Butler or another vendor. I chose to drill the plug using a number 60 drill, don't attempt this with a hardened plug and you should have a dill press for this.

[Tim Corcoran]

Drilling plug to lubricate distributor gear

[PAUL K]

Glad to see your making progress.

For years we installed cam bearings and there was no issue. Now it's been years since we've installed cam bearings without an issue.

[Tim Corcoran]

At the machine shop bearing clearances were verified .026-.027 on the rods and the mains are .029-.031 and that is right about what I wanted. Prior to installing the rear main seal I checked the crankshaft rotational torque and the end play. I installed the crank and torqued all the caps. It took 7.5 inch pounds to get the crank to turn and slightly less running torque. The end play was only .003 and I was not happy with that. After removing the thrust bearings I found that the upper thrust bearing was thicker on one side than the other. using some 120 sand paper laying on the kitchen granite counter top I removed some material a little at a time checking with a mic in three places to make sure I was keeping the surface flat. After removing enough material to even up the surfaces I reinstalled everything and got .007 end play and that's on the lower end of the tolerance and I am happy with that. Next step is to install the BOP one piece rear main seal.

[Tim Corcoran]

The engine I built for my street car last year I used the BOP one piece rear main seal. I made the mistake of letting my machinist install it, thinking letting him do it was my best shot at getting a leak free installation. I was wrong I should have done it my self because it leaks. This time I did it my self following the instructions to the letter and having a couple conversations with Wade to make sure I got it right. I measured the seal groove depth in the block and cap and they were within .003 and Wade said that is well within spec. The seal did require some fitting to get it to fit right but I think I got it time will tell. Seal installed mains all torqued in place, next step is to file fit the rings.