Line hone question...

[charlief1]

I doubt GM went through these pains to prep a block for the line bore. With perfectly round cylinders you may drop leak down a couple % which will not show up as any measurable difference in power. Now if you are planning on making 700+hp it might be worth it if you have a good block to cut down on blow by. The stock block cylinders will be moving all over the place under power at those levels though so it wont matter if they were round on assembly. Just my opinion.

I agree to a point.

Got to remember, when GM put together these motors, they never thought of the mods we are doing to them today. We are 2x, 3x, 4x, 5x and 6x (maybe) the stock power of the original motor.

Ever take apart a stock, unopened motor that was heavily modified? You'll see the shape the cylinders/pistons are in. If the motors are left stock, then probably you can get away from all the extra honing/bore steps. You start adding HP, then everything starts to move.

Billy T.
gnxtc2@aol.com

Both of you are correct except I'll point out 1 thing. When Buick decided to go to Indy they picked Rhere and Morrison to do the machine work for a reason. The machinist name was Ollie and I got to meet him when I did my first engine in the 80's. He used 2 torque plates on the engine for most of the modifications and machining that was done to the Stage II block then, which was what Buick told them was needed. This is on a race block and not a factory street engine so if Buick wanted it done on a racing block why wouldn't you want it done on yours for safety.
I had Rhere and Morrison do my NA in the mid 80's just for this reason and just to bore the block back then it was $638. When I moved back to Texas I was going through some of my stuff and found the reciept. I forgot how much it was then and I'm still amazed.

 

[Pablo]

I agree to a point.

Got to remember, when GM put together these motors, they never thought of the mods we are doing to them today. We are 2x, 3x, 4x, 5x and 6x (maybe) the stock power of the original motor.

Ever take apart a stock, unopened motor that was heavily modified? You'll see the shape the cylinders/pistons are in. If the motors are left stock, then probably you can get away from all the extra honing/bore steps. You start adding HP, then everything starts to move.

Billy T.
gnxtc2@aol.com

and that's exactly why round cylinders in a static environment are even less important on a big HP engine unless you have the time, money, and equipment to recreate the cylinder distortion in the dynamic environment of the running engine. Lets consider for a moment that there is indeed some cylinder distortion when the heads are bolted on. You machine the block with a torque plate attempting to compensate for this and then you run the engine. Now those perfectly round cylinders at 5x the power level of stock are no longer round, so did getting them perfectly round sitting on a honing machine really matter?

Charlief

Did any of those people provide quantitative evidence that there is distortion?
Lets say there was, the needs of an indy race engine are significantly different than 99.9999% of the buicks on this forum. They are working within a strict set of rules that effectively make every car run within single digit % points in power. When this situation exists and you have mountains of money, you can start to throw cash at things to pick up single digit hp. They also have the means to really test these differences and adjust their honing methods to more accurately reflect distortion conditions in an actual running engine.

If there are some concentricity issues, then lets talk about what kind of horsepower we are talking about in a running engine. Isn't that the point?

What kind of power do you think you gained by spending $638 dollars on a "special" hone job vs a regular hone job... 5? 10?
I can think of a lot better ways to spend the difference between that hone job and a cheaper one. 400+ dollars put into heads or cam or intake or chassis could probably go a longer way to reducing your et than some likely tiny hp gain that as of yet still has not been proven.

All I am saying is that I would like to see some numbers, if the hp per dollar gain looks good, I'll shut up

 

[charlief1]

and that's exactly why round cylinders in a static environment are even less important on a big HP engine unless you have the time, money, and equipment to recreate the cylinder distortion in the dynamic environment of the running engine. Lets consider for a moment that there is indeed some cylinder distortion when the heads are bolted on. You machine the block with a torque plate attempting to compensate for this and then you run the engine. Now those perfectly round cylinders at 5x the power level of stock are no longer round, so did getting them perfectly round sitting on a honing machine really matter?

Charlief

Did any of those people provide quantitative evidence that there is distortion?
Lets say there was, the needs of an indy race engine are significantly different than 99.9999% of the buicks on this forum. They are working within a strict set of rules that effectively make every car run within single digit % points in power. When this situation exists and you have mountains of money, you can start to throw cash at things to pick up single digit hp. They also have the means to really test these differences and adjust their honing methods to more accurately reflect distortion conditions in an actual running engine.

If there are some concentricity issues, then lets talk about what kind of horsepower we are talking about in a running engine. Isn't that the point?

What kind of power do you think you gained by spending $638 dollars on a "special" hone job vs a regular hone job... 5? 10?
I can think of a lot better ways to spend the difference between that hone job and a cheaper one. 400+ dollars put into heads or cam or intake or chassis could probably go a longer way to reducing your et than some likely tiny hp gain that as of yet still has not been proven.

All I am saying is that I would like to see some numbers, if the hp per dollar gain looks good, I'll shut up

It wasn't about power Pablo, I was running in SCCA street modified/super modified class at the time. I needed to keep the engine in 1 piece so I went with the best. Thank God that they were only 18 miles away from my house.
My point is if Buick told them that "this is the way we want it" there has to be a reason, isn't there? Maybe I'm wrong but when a manufacturer tells you what to do there is a reason.:biggrin:

 

[Pablo]

Well if you can explain to me how your hone job increased reliability or "safety" in any real sense then I am all ears.

Professional race teams are constrained by rules to the point where their horsepower per dollar ratio is leaning a lot more toward the dollar side than you probably were. That's why they spend insane amounts of money on minor details to get a small edge.

For the rest of us mere mortals, we still have a lot more room to work with in other areas to maximize our horsepower per dollar.

 

[thadeal4real]

the truthe

Pablo preech it

 

[turbodave231]

In a perfect world..........sure, line hone or bore with heads installed.

From my experience, line honing or line boring with heads installed is not practical.......and in my opinion not needed. I doubt you could measure very little if any difference in the main bores honed with or without the heads installed. The BMS book never mentioned this practice either.

I have an RMC CNC V20 with a Nash line bore setup and a brand new Sunnen Line hone at school/work. With both setups, the block mounts to the
machine(s) in V blocks that rest against the deck surfaces.

Torque plates for boring/honing cylinders are a completely differerent subject, You will get completely different measurements with and without the plate in place. I've done it and measured the difference.

 

[Pablo]

Torque plates for boring/honing cylinders are a completely differerent subject, You will get completely different measurements with and without the plate in place. I've done it and measured the difference.

What kind of bore differences did you measure on a 109?

 

[thadeal4real]

#'s?

cylinder wall should only be within 0.0005" and the mains on the v6 buick i doubt you could even measure would be like +/- 0.0002"mabey?how about that 0.0025" oil clearance or the fact that within the first min of fire up/break in you take almost 0.001" off the walls just a thought:wink:

???

 

[turbodave231]

What kind of bore differences did you measure on a 109?

When these engines were originally manufactured, Buick City Plant 36 did not use any torque plate when they honed the bores. But that was production. We are talking about building custom engines, not production engines.

I have a BHJ cast iron plate. Most of the Buick engines I've built had a variety of different aluminum heads (GN1, M&A, S2) and use a variety of different head gaskets (stock composite, Fel Pro 1026, Fel Pro 1006 wire lock, Cometics).

In a perfect world, I'd have an aluminum torque plate that exactly matched the head thickness at every bolt hole for each design head. I'd use bolts or studs that matched the hardware used on assembly. If I were using a Wire lock Gasket, then the torque plate should have a receiver groove too!!

I haven't measured a 109 block.....but, experience with a 016 S2 block after honing showed .0004-.0006" out of round without the torque plate in place. After that, I hone with the plate and the correct head gasket torqued in place.

 

[Squid4life]

I haven't measured a 109 block.....but, experience with a 016 S2 block after honing showed .0004-.0006" out of round without the torque plate in place. After that, I hone with the plate and the correct head gasket torqued in place.

Good info there. I plan to do a similar test on a 109. Torque it all down with a torque plate, correct HGs, and bolts. Then try it with a head on. Then try it with both heads on. Curiosity is getting to me, and will be good info for the masses I assume.

 

[bison]

If anyone is planning on going over 700hp then they should be running an aftermarket block. Those that run big numbers with stock block often have the blocks filled to reduce distortion. Throwing a bunch of expensive machining processes at a stock block doesnt add up imo. Just save up for a few more months and go for the good block. Ive noticed blow by increases much more rapidly on stock blocks when they are pushed hard.

 

[Squid4life]

If anyone is planning on going over 700hp then they should be running an aftermarket block. Those that run big numbers with stock block often have the blocks filled to reduce distortion. Throwing a bunch of expensive machining processes at a stock block doesnt add up imo. Just save up for a few more months and go for the good block. Ive noticed blow by increases much more rapidly on stock blocks when they are pushed hard.

Ha, a few more months? Not in my world. I'd need a real job to do that. :biggrin:

With a full weight car, how fast is 700 hp? Are we talking bottom 9's? 10's?

 

[cylinderhead101]

Cylinders 1,5,2,and 6 moved .0015" at roughly 10, 2, 4, and 8 o"clock...next to the bolt holes and about 1.5 inches down. Cylinders 3 and 4 moved .002". I left .004" to hone and checked for round and straight before I honed. The bores were straight with no plate. The boring bar is nice and it does a grand job. I just wanted to be sure before I torqued the plate. I used ARP head bolts, Victor Reinz gasket, torqued to spec with the plate. The areas next to the holes got larger (bore increased). I line bored the billet caps and align honed the block before doing the cylinders. I had the mains torqued in place while doing the cylinder bores. After machining I double checked the cylinders with the mains removed and got no movement in the lower portion of the cylinders. My dial bore gauge reads to .0001". I also checked the mains to see if the mains moved with a plate on. I could not read anything greater than .0001". I have heads here. I could have put one on the other side to check for other changes but I was backed up in work up to my chin at the time. Oh well. Back to the grind, so to speak.

 

[Pablo]

Cylinders 1,5,2,and 6 moved .0015" at roughly 10, 2, 4, and 8 o"clock...next to the bolt holes and about 1.5 inches down. Cylinders 3 and 4 moved .002". I left .004" to hone and checked for round and straight before I honed. The bores were straight with no plate. The boring bar is nice and it does a grand job. I just wanted to be sure before I torqued the plate. I used ARP head bolts, Victor Reinz gasket, torqued to spec with the plate. The areas next to the holes got larger (bore increased). I line bored the billet caps and align honed the block before doing the cylinders. I had the mains torqued in place while doing the cylinder bores. After machining I double checked the cylinders with the mains removed and got no movement in the lower portion of the cylinders. My dial bore gauge reads to .0001". I also checked the mains to see if the mains moved with a plate on. I could not read anything greater than .0001". I have heads here. I could have put one on the other side to check for other changes but I was backed up in work up to my chin at the time. Oh well. Back to the grind, so to speak.

Good info. It would have been interesting to see how the heads compare to the plate.

 

[Squid4life]

AWESOME INFO! Thank you very much! I have been too swamped to do something similar with heads vs plate, etc. Good stuff, thank you very much!

 

[charlief1]

Good info but I'm wondering what the differences would be on a non 109 block like the 4.1 or earlier 3.8 blocks.