[gtofreek]

I've seen many posts in the past where people say Pontiac blocks don't need to be align honed. That they are good the way they are. Yet I have seen many times where they were out of alignment. So this time I have photo evidence of it. This is a 455 block I align honed the other day, as we align hone pretty much everything. We align hone first, then machine the rest off the mains from there. This way we can get accurate deck heights, Etc.

These pics show the main saddles from 1-5 in that order. I hone .001" out and stopped to check progress. You can see where the front 4 all cleaned up in the .001", but number 5 hasn't cleaned up. #5 cap has been honed on completely, but the block has hardly been touched. Also, I honed .001" out of mains #1, 2, 4, and 5, but #3 had more than .002" honed out of it. That is because it was the high point, and it honed that .002" out of the block, and none out of the cap. It took more than .002" honed out before #5 cleaned up, and #3 cap cleaned up after .003".

[gtofreek]

I started out with .005" to hone out, and these first pics was with .004" left to go. Also, look at #5 main cap after I cut a couple thou off of it. Notice how one side cleaned up all the way across, while the other side only cleaned halfway. That will twist the cap when it is bolted down, unless it's cut flat. That might explain why the #5 main saddle cleaned on the rear part, but not the front. All that force from those rear main bolts being torqued to 120 FT. Lbs. really distorts things, especially if the cap is not flat. I checked the block to be sure it wasn't warped from front to rear, but the pan rails are perfectly flat, so this is just how it came from the factory. This block was align bored from the factory. I have seen a couple blocks that looked to have been align honed at the factory. I believe those blocks were blocks that were not align bored correctly, or off size, so they had to align hone them to fix them. Most Pontiac blocks I see are align bored from the factory.

In the end, it all cleaned up well, and is now on size, and in alignment!

[Will]

Paul, how much does fixing a block in that condition shorten up the distance between main and cam centerlines? Did you have to use a shorter timing chain?

I think it might be fair to say "most" Pontiac blocks don't need to be align honed. But "most" is a pretty unreliable standard if you're building a high performance engine. I certainly wouldn't want to take that chance.

We have to remember these are mass-produced parts and the factory was churning them out in very large quantities back in the day. It's inevitable that some mistakes would slip through. Also, the threshold for inaccuracy was higher in these engines - they weren't built to the same close tolerances that you build a high performance engine. After all, they were only warrantied for 12,000 miles back then and if a car went over 100K it was doing pretty good. Definitely better to measure and check than get burned.

[tom s]

Paul,when Joe Reath was alive and in the engine biz he would not allow a block to go out without the hone.I the customer did not want it he would not do the build.Over the years he had seen some issues with not doing it.FWIW,Tom

[HWYSTR455]

Main alignment checked at minimum, and align hone is SOP on every engine I've ever done. Why in the world wouldn't you do that if it's all torn down and at the machine shop? I just don't get it. That's like not truing the decks up on a rebuild. (Then folks wonder why they have head gasket issues)


.

[mgarblik]

The title of the thread says it all and the pictures show it. What the pics show is the rule, not the exception. Every old Pontiac block should be line honed. As Paul shows, it is a process, and takes time, skill and care. To answer the timing chain and centerline question. If a block is line honed properly, a -.005" timing set may be needed on the 3rd or 4th line hone. We ran an IA II block that had been line honed 6 times with a STD. timing set. The centerline changes based on how much block material is removed when honing. If you cut the caps properly, the vast majority of the material is removed from the purposely egg shaped caps from the cap grinder. If done right, the block only has .0005-.001" removed each time it is honed. There are exceptions, that's why Cloyes makes -.005" and -.010" timing sets. Good info.

[Formulajones]

I have every block align honed that I do. Has to be done, and Paul just showed why. Can't assume anything to be where it should be. The Pontiac I'm assembling now was align honed. I installed a new standard length Cloyes timing set and it's very snug.

Love it when you post up little details Paul.

[gtofreek]

That changes very little. As you can see, the rear main hardly changed in cam to crank centerline. #3 took the biggest hit, but that won't affect timing chain tightness. Rarely ever is a shorter timing set needed.

Originally Posted by Will

Paul, how much does fixing a block in that condition shorten up the distance between main and cam centerlines? Did you have to use a shorter timing chain?

I think it might be fair to say "most" Pontiac blocks don't need to be align honed. But "most" is a pretty unreliable standard if you're building a high performance engine. I certainly wouldn't want to take that chance.

We have to remember these are mass-produced parts and the factory was churning them out in very large quantities back in the day. It's inevitable that some mistakes would slip through. Also, the threshold for inaccuracy was higher in these engines - they weren't built to the same close tolerances that you build a high performance engine. After all, they were only warrantied for 12,000 miles back then and if a car went over 100K it was doing pretty good. Definitely better to measure and check than get burned.

[gtofreek]

Originally Posted by maniacmechanic

Very Nice.

Every Pontiac V8 I have ever owned when I tore it down to rebuild had factory Align Honed Mains. I could see the cross hatch witness marks from honing.
I have been told that only Pontiac Motors did so.

I wonder if late Model LS & LSx & LS -LT-4 Corvette- Camaro have factory align honed mains ? Chevy always took shortcuts. Cheap.

I have several Pontiac V8 engines ready for rebuild here.
Align Hone Check & Re Align Hone on the Machine to do List.

Most everything is align honed now days. They finally realized the importance of it. Even the late model Ford Mod engines, and the late model Hemi's are align honed now.

[gtofreek]

Originally Posted by tom s

Paul,when Joe Reath was alive and in the engine biz he would not allow a block to go out without the hone.I the customer did not want it he would not do the build.Over the years he had seen some issues with not doing it.FWIW,Tom

We won't build one of these old engines without align honing either. If we don't, who does the customer come back to bitch at if his main bearings take a dump? Us, that's who. I have seen many rebuilt engines that were not align honed, and the bearing wear says it all.

[gtofreek]

Originally Posted by HWYSTR455

Main alignment checked at minimum, and align hone is SOP on every engine I've ever done. Why in the world wouldn't you do that if it's all torn down and at the machine shop? I just don't get it. That's like not truing the decks up on a rebuild. (Then folks wonder why they have head gasket issues)


.

Problem with just checking them is they may check on size, but trying to check for alignment is almost impossible. Feeler gauges just don't come thin enough to check it.

[gtofreek]

Originally Posted by mgarblik

The title of the thread says it all and the pictures show it. What the pics show is the rule, not the exception. Every old Pontiac block should be line honed. As Paul shows, it is a process, and takes time, skill and care. To answer the timing chain and centerline question. If a block is line honed properly, a -.005" timing set may be needed on the 3rd or 4th line hone. We ran an IA II block that had been line honed 6 times with a STD. timing set. The centerline changes based on how much block material is removed when honing. If you cut the caps properly, the vast majority of the material is removed from the purposely egg shaped caps from the cap grinder. If done right, the block only has .0005-.001" removed each time it is honed. There are exceptions, that's why Cloyes makes -.005" and -.010" timing sets. Good info.

Always like your posts Mike! Wise words from a wise man!

[TedRamAirII]

Originally Posted by gtofreek

We won't build one of these old engines without align honing either. If we don't, who does the customer come back to bitch at if his main bearings take a dump? Us, that's who. I have seen many rebuilt engines that were not align honed, and the bearing wear says it all.

Yes Paul. I would most certainly just add it in as part of the job, just like cleaning the block. If they don't want it done, then you dont want the job. Its "your way or the highway". Its your name on it when something goes south. Reputation is everything.

[gtofreek]

Originally Posted by TedRamAirII

Yes Paul. I would most certainly just add it in as part of the job, just like cleaning the block. If they don't want it done, then you dont want the job. Its "your way or the highway". Its your name on it when something goes south. Reputation is everything.

This is one of those cases where the customer is not always right!

[Formulas]

All this is good and I used to have this philosophy until circa 1982 I bought a nice original stock XF 4bolt 1970 455 block had it aligned honed before I put it together it ran good for a year or better then burnt a rear main bearing trial fit new bearings crank wouldn't turn out for a rebuild and another align hone this time I ran the engine for about another 6 years no problem de, commission the engine torn it down and had copper showing on upper front 2 main bearings.... In hind sight I wish I had left it alone because I ended up taking the main caps off and personally tossing it into the dumpster at a scrap yard... New timing chains were loose and this was before internet and options we have now.... Point being I wouldn't walk into any machine shop and say just do it without KNOWING they are fully capable of the task in a precise manner and that the block NEEDS it or you might end up worse than you started...... Fortunately most of my engine work since has been high mileage takedowns and if the bearings look great you couldn't pay me enough to let someone touch it....... With that said yes the crankshaft saddle should be as near perfect as possible I'm all in on that.

[grandville455]

Originally Posted by mgarblik

The title of the thread says it all and the pictures show it. What the pics show is the rule, not the exception. Every old Pontiac block should be line honed. As Paul shows, it is a process, and takes time, skill and care. To answer the timing chain and centerline question. If a block is line honed properly, a -.005" timing set may be needed on the 3rd or 4th line hone. We ran an IA II block that had been line honed 6 times with a STD. timing set. The centerline changes based on how much block material is removed when honing. If you cut the caps properly, the vast majority of the material is removed from the purposely egg shaped caps from the cap grinder. If done right, the block only has .0005-.001" removed each time it is honed. There are exceptions, that's why Cloyes makes -.005" and -.010" timing sets. Good info.

That's what my engine guy does too, takes the caps out of round, not the block.

[Skip Fix]

Here only a few shops have 3.25 fixtures for 455s.

[ponjohn]

If this weren't done, what would be the effect?

Long term durability issues?

[mgarblik]

Originally Posted by Skip Fix

Here only a few shops have 3.25 fixtures for 455s.

Yes, that can be an issue if the shop does almost all small blocks. For the majority of main bearing housing bores in American V-8's it takes 3 honing mandrels. They are very expensive. One that will do 3.25" mains is over 3K loaded with shoes and stones. They also have to be taken care of, stored properly, stones dressed, shoes checked and tightened. There is allot to it. I do not have a mandrel to do the 55mm cam tunnel we run. The bore size is 2.282". There is a shop in town that will loan me theirs when I need one. I always hand them $50.00 every time I borrow it because I know how much they cost.

[hurryinhoosier62]

Originally Posted by mgarblik

The title of the thread says it all and the pictures show it. What the pics show is the rule, not the exception. Every old Pontiac block should be line honed. As Paul shows, it is a process, and takes time, skill and care. To answer the timing chain and centerline question. If a block is line honed properly, a -.005" timing set may be needed on the 3rd or 4th line hone. We ran an IA II block that had been line honed 6 times with a STD. timing set. The centerline changes based on how much block material is removed when honing. If you cut the caps properly, the vast majority of the material is removed from the purposely egg shaped caps from the cap grinder. If done right, the block only has .0005-.001" removed each time it is honed. There are exceptions, that's why Cloyes makes -.005" and -.010" timing sets. Good info.

Well said, Mike. If a machinist is able to remove enough material from the saddles through align honing to warrant an undersize timing set, he's done something VERY wrong. The same goes with align boring. A COMPETENT machinist should be able to limit the amount of material removed from the saddles.