AMC head torque plates

[Holeshot]

BHJ makes them & LOTS of other COOL stuff as well.

A little under $400

http://www.bhjinc.com/1products/0-landing.htm

[tomcat]

Nowhere nearby has a amc plate. And i have still 4 unbuild engines laying around. So im considering buying such a plate.
What is the difference between the steel and the aluminium plates? Dont tell me you need different ones for cast and aluminium heads ;)

[Rogue Racer]

Honestly, you probably do.

The real effectiveness of using honing plates is to duplicate what the engine sees when assembled so that any distortion to the cylinder case is induced before honing. After the engine is assembled, the cylinders will be the same - straight and round. There are lots of different opinions and viewpoints to discuss concerning the use of the plates, but there is a method that I have seen used by many successful performance engine builders. That method is to assemble the component parts on the engine block and carefully measure the cylnders to detect any distortion. This will take lots of time and an accurate dial bore gauge. When it comes time to hone the block, then install all the component parts that created any cylinder distortion in the same manner as they will be installed when the engine is running. This can include (but not necesarily) the bellhousing, front cover, motor mounts, oil pan, and circulating hot water through the block.

The purpose of the plates is to simulate the cylinder heads being installed while retaining access to the cylinders for machining operations. This means that to be absolutely accurate, you have to install the cylinder heads you are going to run on the block with gaskets like you will use and measure the distortion (or lack of) in the cylinders. Then install the plates and work installation procedures (material of the plates, torque values, bolt types, gasket, torque sequence) to duplicate what you measured with the cylinder heads installed. You may find that duplicating the distorting forces is simple or complex. Every engine design has its method. Record your techniques and duplicate it when honing your cylinders.

Learn about "plateau honing".

Cylinders that are round and straight are the single most productive factor in a high performance engine.

[tomcat]

What would you do in a situation like me? The engines should be not for race or strip, just strong dependable engines.

except one or maybe two engines they will all get cast heads (3x 360 w. cast, 1x 401 alu)

sooo...

1. save the money and torque plate
2. buy a steel torque plate and beein little bit less then optimal on the alu head block

Both plates are too expensive for me, even the single one is already some sort of luxury

[82Waggy]

tomcat, where are you located?

[tomcat]

pm send

[82Waggy]

I see your dilemma.

Perhaps you should look at it from a cost per unit perspective. You are building 4 engines - a torque plate would add what, $50-75per engine.

You could always sell or rent it out after you have finished with it.

I'd consider at least option 2.

[Rogue Racer]

I suspect you could approach duplication of the aluminum head with the cast iron plate (not steel). You might have to adjust the torque amount or sequence or maybe even adjusting the amount of torque per bolt depending on the length of the bolts. Just bolt the aluminum heads on the block, turn it over and measure accurately the cylinders. Measure in several locations around the cylinders and at different heights in the cylinders. (you will find most of the distortion in the upper 1" of the cylinders.) Then bolt the plate on the block and measure again. Some common sense and trial and error should get you in the ball park. If you can get the cylinder within 2 to 3 tenths with the cast iron plates, that will be good enough.

[tomcat]

Thanks for the tipps! Btw. how much deflection does a block have with boltet on cylinders? Did never measure it, so im curious how much that is.

[Rogue Racer]

Depends. Early 390 distort more than 401s. 360s distort more than 343s. 290s are pretty rock solid. I have seen as high as .0023" on one 390 block.