Home Engine Building Machining

[madmikeracing]

Interesting Measurments on block!!
I am not sure anyone measures like this but heres some results . Mike I finally have the proof I was hoping NOT to have. I didn't want to believe a hone or torque platewas really necessary when having these blocks honed/bored out. In my case I didn't need to have the case bolted together - but I sure as hell would've benefited from a hone plate.

Today my motor builder measured the bores of my freshly bored block. The case was split and each side was bored withOUT a hone plate. The machine shop bored to CP's specs, .0030" clearance. Pistons matched to bores. The builder torqued the case together and measured - ZERO bore distortion with the cases bolted together. Next he torqued the BHJ hone plate to the block following Ron's (Axis) ARP stud procedure. The result was .0025" piston to cylinder wall clearance towards the top 2" or so and no longer round.. lower bore stayed true. My motor builder will be doing his best to fix this.

Have your block machined with a hone plate. It costs about $300 to buy the hone plate from BHJ. Just interesting now probably doesnt matter but I feel a Torque Plate on the Bottom and the Top of a GS Block is necessary to do nuice work.. Just my 2 cents worth!! Mike

[Nessism]

Not so sure about this "hone plate" business. If you take a GS cylinder block and heat it up to 300F or so the liners will slide right out. This suggests to me that when the engine is at running temperature the cylinder expands more than the liner and thus, the cylinder itself is not compressing and distorting the bore roundness. The liners are not compressed in any way from the bottom either. They are held in place by the lip at the top of the liner, and then basically allowed to float inside the cylinder, which acts as a loose guide of sorts. I don't see what a hone plate would do other than hold the liner tight at the top. Maybe you could use this plate and then heat the cylinder to 300F before honing? That might work since it will expand the cylinder itself and allow the cylinder liners to float like they will at running temps. Just thinking out loud but that sounds like it may work.

[gs11ezrydr]

I have done quit a few GS 4 cylinder blocks over the years with no problems up to 3mm's over on the 1100's with them not changing clearances after being bolted down to the blocks. I have not tried any big blocks so can not say anything about the 80mm and up stuff. Been doing it for about 25 years now. And my boring bar is about 35 years old now. I have also done Triumph twins, XS 650 twins, with iron blocks, lots of singles up to 101 mm's and they stayed straight after being bolted to the blocks. I use all Sunnen hones and keep my stones straight and true by using truing sleeves to keep them at 100%. I also have a couple sets of stones with different grits that have four stones and four cutters each so they themselves keep the bores straight. Never done any Harleys and I know they recommend torque plates I believe because the bores are so large with iron blocks, just my guess. I also use two eight inch parallel bars on each side of the sleeves top and bottom and clamp them with sleeves that stick out of the block pointing up while boring them. Since I agree with the earlier reply of the cast iron bores floating in the aluminum blocks. I think keeping them aligned is more important that a torque plate so you don't have the cylinders staggered towards the front and to the back. A torque plate would make that a lot easier for sure by keeping them aligned. I also let all my tools stay at the same (room) temperature, pistons, blocks, micrometers, bore gauges etc. so every thing measures the same. Hone, measure, then cool, and repeat until my bores are straight and round top to bottom. Also do all my own valve seat cutting by hand three to 5 angles if needed, solid pilots and neway cutters, Install all my own guides and ream and hone them also. Built rubber plugs to fit the ports to vacuum test them also. Old school defiantly. Time consuming for sure. But usually get excellent results.

[madmikeracing]

Excellent Replies Guys! Thanks, That convinces me regarding the Torque Plate thing. What started all this was a call to a engine shop and they told me YES WE ALWAYS USE TORQUE PLATES ON ALL MOTORCYCLE BORES WE DO!!! Yeah more Bullishness I'm not surprised. I think also reading far too much on the Internet is actually Harmful ha ha there's so much misinformation on it . Anyhow thanx Guys Much appreciated This has unfortunately given me a new Idea on the Ultimate boring setup for my GS engines, Mike

[GregT]

From what my local machinist tells me, gs1100ezyrydr has hit the nail on the head, hone, COOL, measure etc...
Too many shops don't allow cooling time after a cut and frequently the unsupported sleeve ends finish up smaller than the end in the block. Surprising amount of heat generated doing a big overbore.

[madmikeracing]

Yes I agree , Man funny how many people give wrong answers and dont care to do things Properly, . Thanx Guys Interesting Post! now how bout home seat machining in a Milling Machine??