[CNC BLOCKS NE]

Originally Posted by cobalt327

That's interesting.I can see how bolting up the plates ahead of time could help. To professional race engine builders, ANY advantage is big!

I'm sure you can remember how the deal was years ago (before there were aftermarket or 'specialty' factory blocks available like from GMPP, MP, and FRPP). Take a new production block and build it into a tow truck/parts chaser mill and run it like that to "season" the block. Afterwards, the block would be machined/blueprinted before being assembled into a race engine.

Using a new block instead of a high mileage passenger car block was preferred; the seasoned new block would be finished for forged standard bore pistons, and that retained a little more bore thickness over using a used block.

Nowadays, I see little reason not to use torque plates for finish honing, though. Any shop worth their salt should be capable of doing it that way and for the added cost I believe it's a wise investment unless it is a grocery getter being built. But in days gone by, there were some very bad-A engines built that never saw a torque plate, so it just goes to say that there's always more than one way to get the job done!

80% of my circle track engines are used castings but trying to find one that will pass a sonic test is another story. I do machine alot of Dart blocks and so far no problems with their castings.

I do ALL performance work and have used a plate on every engine I have ever built.

My shop specializes in blue printing blocks including cam tunnels, lifter bores and having a HAAS 4-axis CNC machine and to finish the block off correctly its done with a plate plus I use the same hardware and gasket to be used in the end build.

I have even built some grocery getters with torque plates and a blue printed block that do run better then new according to the customers!!

[painted jester]

Originally Posted by CNC BLOCKS NE

80% of my circle track engines are used castings but trying to find one that will pass a sonic test is another story. I do machine alot of Dart blocks and so far no problems with their castings.

I do ALL performance work and have used a plate on every engine I have ever built.

My shop specializes in blue printing blocks including cam tunnels, lifter bores and having a HAAS 4-axis CNC machine and to finish the block off correctly its done with a plate plus I use the same hardware and gasket to be used in the end build.

I have even built some grocery getters with torque plates and a blue printed block that do run better then new according to the customers!!

Thanks: nice to know about using the gasket and same hard wear with a plate!!

Jester

[CNC BLOCKS NE]

Originally Posted by painted jester

Thanks: nice to know about using the gasket and same hard wear with a plate!!

Jester

I see more distortoin on OEM blocks as they seem pretty frail compared to a Dart unless the bores are maxed out.

[painted jester]

Over the years I have never had any bad blocks bought new that were cast in the united states! I guess I may have been lucky! But the Mexican blocks I'm Leary about any more! I didn't say American Because Canada, U.S.A, Mexico and all of the country's in South America Are American We have no monopoly on the Phrase " made in America" My wife's Canadian She just reminded me for the Millionth time while punching my shoulder LOL

I like the dart blocks! I don't like eagle cranks! but everyone brings me eagles for their builds! When a guy wants to buy a mexican block I always suggest Dart or other quality block! and if they stick with the Mexican I want the money up front for the machine shop I send it too!!! or I dont take the job!!! When you tell a customer that during testing and machining a flaw was found in the block they dont want to pay! And they already have money invested in the block they ordered

Jester

[PatM]

Really a great thread regarding dimensional stability in engines. Thanks to you all. I'm not a machinist or a racer, but I'd have guessed that the thermal cycling was to to cause the plates and the block to shift, seat, and become "happy" with one another. In other words, the residual stresses were balanced by the thermal cycling so that the plates and block were "loaded" akin to an assembled engine after some thermal cycling (running) time. Boring and honing while at an elevated temperature is also very interesting. How did the shop you were in stabilize the temperature for the full machining cycle? I believe stability in this case is as important as elevating the temperature to start with. Do you agree? I find this all very interesting, and hope the discussion goes on . . .

PatM

[cobalt327]

When I was racing slots competitively (FL state champ in the mid-90s in International 15), I had a problem w/the brushes floating at the top end. Think of it as the equivalent of floating the valves. This was after refinishing the armature commutators very carefully w/my commutator cutter. Tried using different cutters, different speeds for the rotation and the cutter feed, and nothing seemed to help.

Finally, on a hunch I used a hot air gun to heat up the spinning arm before cutting the comms. Even though I couldn't measure a difference, there WAS enough of a difference to add several thousand useable RPM to the motors. And the bigger benefit was the comms and brushes quit arcing, which meant the motors could almost always go an entire race w/o replacing the brushes and springs- and that was time that could be now spent on other chores between heats (you race for 8 minutes then have only have 3 minutes to change lanes and do the needed maintenance, repeat 8 times).

I mention this only to agree that there can be subtle differences when machining parts at room temps as opposed to running temps.

[CNC BLOCKS NE]

Originally Posted by PatM

Really a great thread regarding dimensional stability in engines. Thanks to you all. I'm not a machinist or a racer, but I'd have guessed that the thermal cycling was to to cause the plates and the block to shift, seat, and become "happy" with one another. In other words, the residual stresses were balanced by the thermal cycling so that the plates and block were "loaded" akin to an assembled engine after some thermal cycling (running) time. Boring and honing while at an elevated temperature is also very interesting. How did the shop you were in stabilize the temperature for the full machining cycle? I believe stability in this case is as important as elevating the temperature to start with. Do you agree? I find this all very interesting, and hope the discussion goes on . . .

PatM

I looked at hot honing years ago. So far I have not had any ring seal issues leak downs at temp seem to be 2%.

Problem with hot hot honing I don't think you could get any one to pay for it.

I also find on OEM blocks with a lot of heat cycles the main lines are not very straight I have 2 line set ups one at each shop and they get used a lot.

Look at these main bearings with 400 miles on a newly rebuilt engine and the shop that built the engine said the main line was fine.

[engineczar]

Originally Posted by cobalt327

When I was racing slots competitively (FL state champ in the mid-90s in International 15), I had a problem w/the brushes floating at the top end. Think of it as the equivalent of floating the valves. This was after refinishing the armature commutators very carefully w/my commutator cutter. Tried using different cutters, different speeds for the rotation and the cutter feed, and nothing seemed to help.

Finally, on a hunch I used a hot air gun to heat up the spinning arm before cutting the comms. Even though I couldn't measure a difference, there WAS enough of a difference to add several thousand useable RPM to the motors. And the bigger benefit was the comms and brushes quit arcing, which meant the motors could almost always go an entire race w/o replacing the brushes and springs- and that was time that could be now spent on other chores between heats (you race for 8 minutes then have only have 3 minutes to change lanes and do the needed maintenance, repeat 8 times).


I mention this only to agree that there can be subtle differences when machining parts at room temps as opposed to running temps.

Ah a fellow slot-head, I set the box stock 15 record for a Blue King back in late 80's. Lots of fun.

[painted jester]

Originally Posted by PatM

Really a great thread regarding dimensional stability in engines. Thanks to you all. I'm not a machinist or a racer, but I'd have guessed that the thermal cycling was to to cause the plates and the block to shift, seat, and become "happy" with one another. In other words, the residual stresses were balanced by the thermal cycling so that the plates and block were "loaded" akin to an assembled engine after some thermal cycling (running) time. Boring and honing while at an elevated temperature is also very interesting. How did the shop you were in stabilize the temperature for the full machining cycle? I believe stability in this case is as important as elevating the temperature to start with. Do you agree? I find this all very interesting, and hope the discussion goes on . . .

PatM

Man: its too hot to be in the garage im going looking for an air conditioner at some yard sales to put in there!!!LOL Does that mean Im a Puss!! I just came in to cool off! and did a search for hot block honing !


http://www.circletrack.com/techartic...ing/index.html
Cylinder Block Honing - Honed To Perfection
Here’s The Result When Solid Engineering And Practical Experience Collide In The Study Of Making Cylinder Block Bores Concentric...At Operating Temperature
From the February, 2009 issue of Circle Track
By Jim McFarland
Photography by Dennis Wells


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It is widely recognized that cast, machined metal parts tend to have “memory” created from internal stresses. In the presence of temperature changes, these stresses often cause dimensional and structural shifts. Racing engine builders know about this condition that can have a direct bearing on cylinder bore concentricity. In fact, we often spend extra time and funds to produce “round” cylinders in an attempt to produce bore dimensions equal to those that exist after an engine reaches operating temperature and cylinder pressures.

More specifically, cast and machined bores in a cylinder block are subjected to thermal and load distribution that add complexity to the goal of maintaining concentric bores in a running and highly stressed engine. Like it or not, there’s some “Kentucky windage” built into the task of producing dimensionally correct cylinder bores that model those subjected to in-use heat.

We know the distribution of operating temperatures and combustion pressure are anything but uniform in the metal structure surrounding cylinders and the fact that three-dimensional growth of block material occuring in this proximity is unavoidable. So, we’ve contrived ways to pre-load blocks with honing plates; by heating the material or use of other methods intended to anticipate how a given block will experience bore distortion, once assembled with parts and running ... sometimes on the assumption that all bores will distort the same, which they do not.

None of this is to suggest such methods are not effective, because they have been and are. Rather, these comments go directly to the problem of devising improved ways to compensate for the “effective” distortion that is inescapable under the influence of operating conditions.

Enter Stephen Kuzara of Sheridan, Wyo.-based Millennium Products Corporation. Stephen’s background is essentially two-sided. At 53, he has engineering training, 35 years as an engine builder/machinist and 16 years running his own machine shop. That’s not an unworthy combination. During his time as a machinist when the use of torque plates came into common use, it appeared to him there must be other ways to produce concentric bores once put into operation.

In prior conversations he’d had with Smokey Yunick (who had tried the process of “hot honing” during the 1950s), Kuzara explored ways to circulate heated liquid through the cooling jacket of a cylinder block during finishing honing operations.

“Curiosity and frustration arose from chasing the final few tenths in the honing process,” Kuzara says. “During the early ’70s, I worked with a machinist friend who owned a CK-10. I began wondering how important those last few tenths were in the overall effort of achieving precision-machined blocks. I’d already observed how the stones would heat the bore surfaces and create dimensional changes, so it seemed logical some major changes would probably occur at engine operating temperatures.”

In fact, Smokey had abandoned the process (although in the ’70s he’d shared with this author the benefits he’d projected would occur), considering the way he’d tried the method was cumbersome, “messy,” and “took too long.”

Kuzara appears to have been more persistent. “My first setup was hooked up to our hot-water heater, with one hose running water into the block and another running out to the drain,” he says. “The outlet hose had a pressure gauge and a valve to help monitor the pressure and control the flow. Water temperature during the first test I ran was at 180 degrees F. The distortion measured was significant enough that I quickly concluded the last few tenths I had been chasing ‘cold’ were lost in the greater distortion I was seeing ‘hot,’ which was several times that produced by torque plates.”

Interpretation? While torque plates do pre-load and create bore distortion, thereby providing data that enables improved honing precision, the process of hot honing (using torque plates) appears to create and allow material movement that closely relates to cylinder dimensions of a running engine at temperature. In the following portions of this story, you will find data and commentary intended to help you form your own opinions, but the evidence is pretty clear. Stephen has subsequently licensed the technology to Kwik-Way for manufacturing and marketing purposes.

Typical bore dimensional variations For purposes of this story, four small-block Chevrolet cylinder blocks were selected from inventory at Wells Racing Engines in Duncanville, Texas: a stock 350, stock Bow Tie, a 0.060-overbored Dart and a Dart Little M (lightened). Elsewhere in this story there are charts of data provided, each of which presents cylinder bore dimensions obtained (1) “cold” (65 degrees F) with a torque plate and “hot” (200 degrees F jacket temperature and 195-degree F torque plate coolant temperature). Cylinder bore measurements were taken as “long” (parallel to crankshaft axis) and “thrust” (perpendicular to the crankshaft axis). Also, three measurements per cylinder were taken: top, middle and bottom.

Spend a little time examining the accompanying charts. From them you can determine the dimensional differences and accuracy measured between the two methods used: torque plates and hot honing vs. neither. Particularly interesting is the data that shows the number of honing passes required to bring a cylinder into concentricity as depicted in the chart entitled “Dart Little M Lightened” (note cylinder No. 4). This same chart also shows a comparison (same cylinder) of cold readings at 60 and 70 degrees F and one at 70 degrees with the torque plate removed. Here, the two readings make a direct comparison between readings with and without the plate. Remember, all readings are shown in tenths of a thousandth an inch.

Some concluding thoughts Is hot honing worthwhile? Some observations may be made from information gathered in this story. For example, with the use of torque plates, stresses and bore distortion created by the installation of cylinder heads can be imposed. Therefore, it’s possible to finish-hone cylinders to compensate for such deformities. However, the body of information gathered from hot honing indicates greater bore distortion is created by circulation of hot water through a block’s cooling jacket than by cylinder head clamping forces.

It was also apparent that cylinders in blocks that have been “lightened” will notably benefit from the hot-hone process and should be finish-honed after all material is removed.

Finally, as noted by Wells, bore-gauging cylinders that have been hot-honed and allowed to cool will produce measurements that appear quite skewed. Once brought up to temperature, these same cylinders will assume the desired concentricity and, according to the data, be more concentric than if the hot-hone process had not been employed.

Where simulations or approximations are used to approach in-use conditions (in a variety of engine or parts applications), the nearer a process comes to duplicating those conditions the more beneficial it becomes. In terms of cylinder bore concentricity and preparation, it appears the hot-hone process closely approximates the dimensional environment of a running engine’s cylinders. Smokey would likely have approved.

Read more: Cylinder Block Honing - Engine Machining - Tech Review - Circle Track


I hope it helps anyone interested! I also hope its showing up I had no trouble posting articles before but the last few days I have !

In 1968 I worked for a speed shop in Troy Mich. and pit on the seaton shaker (the corvair not the chevelle) We were talking about hot block machining then! Its funny it never caught on in the main stream of the industry!

Chris

[cobalt327]

Originally Posted by engineczar

Ah a fellow slot-head, I set the box stock 15 record for a Blue King back in late 80's. Lots of fun.

Yeah, it was. Box 15 is one of the most competitive classes- we used to pull 100-plus entries in just that class in the statewide races. Sorry, above should read " ...3 minutes then have only have 3 minutes to change lanes and do the needed maintenance, repeat 8 times." Open class (Group 7) ran 5 on/3 off x 8.

I raced in the '60s as a kid, RTR's, Cox Chaparrals, that sort of thing, got into scratch building when the local track closed. Got quite an eye opener the first "real" race I went to in '92.


Open motor. It can be covered w/a quarter, makes about 1/4 hp. Hand wound arm, cobalt magnets, ball bearings (2mm shaft) both ends. About $300 in parts per motor if you pay retail.

End of off topic.

[painted jester]

Originally Posted by cobalt327

Yeah, it was. Box 15 is one of the most competitive classes- we used to pull 100-plus entries in just that class in the statewide races. Sorry, above should read " ...3 minutes then have only have 3 minutes to change lanes and do the needed maintenance, repeat 8 times." Open class (Group 7) ran 5 on/3 off x 8.

I raced in the '60s as a kid, RTR's, Cox Chaparrals, that sort of thing, got into scratch building when the local track closed. Got quite an eye opener the first "real" race I went to in '92.


Open motor. It can be covered w/a quarter, makes about 1/4 hp. Hand wound arm, cobalt magnets, ball bearings (2mm shaft) both ends. About $300 in parts per motor if you pay retail.

End of off topic.

Its great you posted about slot car racing we had some big tracks in Detroit I used to take my cars to. Brought back memory's I can even smell the oil and electricity ( isn't that funny) and after all these years!!

Thanks for the memory's: Chris