[PontiacLars]

Thank you

[steve25]

No problem!

[Formulabruce]

"Align hone" will raise the crank in the block. IF the front or rear Crank seal is Off a bit, they can leak. Recommend the motor is " smoked" before installing.

[Gach]

Yes it rises crank up in the block. Just thinking out loud, usually for line hone, they take .002 to .003 off main caps. So if my math is correct, it actually only Rise it 1 to 1 and haft thousands up. Went though this with a guy, who kept insisting he needed a .010 or .005 shorter chain. After playing with 3-4 different chains and gear sets, he discovered didn’t need either. .005 or .0010. Shorter

When you get into line bore not hone thats when it changes not exactly sure on how much. But pretty sure that’s were a shorter chain comes into play. Then it may alter the situation for the rear main seal.

Its been a while since I’ve had one line hone or bored, so correct me if I’m wrong. To me a block thats that bad it needs a line bore would be the last resort if I couldn’t fine another block.

[mgarblik]

Speaking in generalities a little here and it depends on the equipment and how a shop likes to utilize it. In general though, most shops will line bore a block only when new main caps are being installed or a damaged cap or two are being replaced. If the machinist is good, they can set up the block so that almost all the material removed is from the bearing caps. When line honing, since it's abrasive material removal, material is removed from caps and the block. Removal is fairly equal, which helps make the bores round, but there are some exceptions. If the caps and block are different material; aluminum block, billet steel caps, iron block, billet caps or iron caps, it gets more complicated. The softer material generally has more material removed. There is quite a bit of finesse involved and you can cheat a little with different stone materials and lubricants, pressure and technique. As mentioned, a good machinist can align hone a block 3-4 times before a shorter timing chain is needed.

[track73]

Speaking of line hning or boring ;HO's book said Pontiac blocks rarlely need that process. Check the main bearing bores and if you can read the bearing numbers it'd ok.

[tom s]

Something not talked about but can be an issue if not checked is cam tunnel.Most of the problems we have found has been on 455 blocks?Tom

[mgarblik]

Originally Posted by tom s

Something not talked about but can be an issue if not checked is cam tunnel.Most of the problems we have found has been on 455 blocks?Tom

Very true, Tom. There is not a single shop within 150 miles of me that has a line hone mandrel small enough for cam bores. Would love to have one. They are nearly $5000.00 for a loaded mandrel with stones and guides. Then you need to have the availability of oversize cam bearings which is an issue for most engines out there. It's quite an undertaking. Quite a few Pontiac engines, I have to hand scrape 1 or more cam bearings. FE Fords are the worst I run into. Very rare to have a cam just slide in properly without needing some hand work. Every camshaft we install at the school must pass the 2 finger test. If the camshaft can not be turned smoothly with 2 fingers on the nose, it has to be addressed before continuing the build.

[tom s]

My shop here can do them,too tight has been a couple issues.This shop does about every kind of engine you might think of,from the smallest import to dsl.Tom

[Gach]

So many things that have to be checked on stock block. But please don’t get discouraged guys hearing all this.

[Stan Weiss]

Originally Posted by Gach

So many things that have to be checked on stock block. But please don’t get discouraged guys hearing all this.

While there is less chance that they are off, all of these things should also be checked on an after market block.

Stan

[mgarblik]

Originally Posted by Gach

So many things that have to be checked on stock block. But please don’t get discouraged guys hearing all this.

Agree completely. We have to realize the "newest block" for our beloved Pontiacs is 44 years old. We work with all kinds of engines in my classes. From Model A Ford to Modern Hemi and almost everything in between. Couple things I have learned over the decades. 1. All the engine rebuilding equipment was designed and tested around the SBC platform. Cylinder hone, line hone, surfacing equipment, seat and guide machine, everything. That makes rebuilding one the easiest engine out there. That just makes sense. All the fixtures, set-ups, tooling, is just plug and play. The farther and farther you deviate from that platform, the more complicated and time consuming the rebuild becomes. 2. Newer, CNC or at a minimum computer based machines are easier to adapt to different engine families and configurations. 3. The Pontiac V-8 is a VERY sound engine platform with only a few design features that need special attention during a rebuild. 4. Every engine platform has it's good, better and best features. That's why some people are still passionate about certain engines. 5. All the old American V-8's were designed with a huge safety factor to allow for greatly increased power output without worry of failure. 6. Any GOOD engine machine shop with people who care about what they are doing, should have NO PROBLEM machining a Pontiac V-8 block.

[Dragncar]

Well, if you have a known good running PMD Pontiac V8 to rebuild you at least know it runs good, holds oil pressure and water pressure without leaking into one another.
You know it does not have to be align bored or anything else major to function correctly. Might want to sonic check for over bore.
A aftermarket block that has never been run you had better check everything you can.
My 455 that ran for decades never was align bored or decked.
Even put ARP main studs in 4 bolt block and ran it.
Hand polished my crank 2 times and balled honed the bores 2 times.
Tough engines.
I will ridged hone the bores .065-.070, get a new crank and run it again someday. Probably 4" crank.

[Gach]

It really really depends on what your intentions are with a stock block. They do have a hp limit.

[Gach]

The new issue that has cropped up in past few years is pin hole leaks in one of the cylinders. Had it happen to a friend in his all original 67 GTO. Evidently they rust from inside out. Had to have it sleeve, also just saw 64 Speed go through same thing. On a block he pick up. So question is, do you go though the process of having it pressure tested. Kind of scary to think about. This is something new to me.

[mgarblik]

We thermal clean and shot blast every block which cleans the cylinder barrels inside and outside. Then pressure test every one. Nothing worse than spending hundreds of hours building and engine to find out you have an internal water leak or an oil passage breech. If it passes a pressure test, very slim chance you will have a problem.

[Gach]

Originally Posted by mgarblik

We thermal clean and shot blast every block which cleans the cylinder barrels inside and outside. Then pressure test every one. Nothing worse than spending hundreds of hours building and engine to find out you have an internal water leak or an oil passage breech. If it passes a pressure test, very slim chance you will have a problem.

WOW ! So glad to hear that. My thoughts exactly.

[Gach]

I’ve had blocks baked and tumbled, it’s unbelievable of course with freeze plug out, then you can look inside with a small mirror and they look like brand new inside it’s amazing. Then pressure tested. Unfortunately for me that machine shop no longer exist. Name of the shop was Dyno Time it was nice because the owner had set a record with his Pontiac years ago. Can’t remember what class he was running. Butler bakes all their blocks for motors they build and I imagine pressure tested them to.

[steve25]

Yes, as recall from the 90s at Lebanon valley dragway the onwer of Dyno time had a late 60s or early 70s GP that ran deep in the 9s.

I forget if the car was purple or a deep blue?

[Gach]

Yep thats it, think it was blue 70 GP.