"Angle Milling" heads

Your drawings help illustrate your intentions very well.
Only the top of the head should be parallel to the bottom of the head (now) and when the head is bolted to the block, the head is no longer parallel to the crank.
Which means -
The head nut seats are not perfectly perpendicular to the crank the way they shoukd be.
So your proposed angle milling of the head "should" actually fix that problem.
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I'm wondering if your studs have all been tweeked by this problem since the engine was new?
 
Forgive me for not having read all of the posts here, but have you tried swapping heads side to side for measuring only? See if the "taper" still exists with the particular head or if it remains with the side of the block.
 
I'm surprised a block can have the head face out by .030". Surely it couldn't have come from the Factory like that.

Strange indeed.

Mart.
 
Just a couple of things that should be noted. There are no studs involved because this is an 8BA; just bolts. Swapping the heads side for side won't help, even for measuring, , because it would put the back chamber over the front cylinder. Besides, I have spent a lot of time measuring both heads (on and off the engine), and I am convinced the problem lies with the block (which I have also spent a lot of time measuring).

"Mart" - As I alluded to in an earlier post, I attribute this problem to an earlier, inferior rebuild with a poor deck job. Given this situation, I am loathe to deck the block even more and believe it is the more prudent approach to try to correct this situation by working with the head rather than the block. Given all of this, I really don't think the .030" difference over 20" would have prevented the engine from being assembled or running properly.

If I can get the chambers equal (and I expect I can) I don't see what the problem would be. The only thing I can think of would be with gasket leaks. I will be using my "tubing method" to positively locate the head and gasket to minimize the chances of this.

(I wish I could have "GOSFAST" install his locating pins on this setup, but I am to far down the road on this project (and too darn far away as well).
 

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I'm not really an engine expert, but I am thinking you do not want the chambers equal. Well, sort of, but not. If you have the chambers in the heads equal, the cylinder with the piston highest relative to the head face will have the highest compression. the compression will be reducing as you go along to the piston at the other end of the block.

Your original proposal to angle mill the heads to equal things up may be the best option, but the chambers heed to be different volumes to allow for the different piston heights above the deck.

To be honest, two wrongs don't make a right. It will never be right, but I suppose your proposal will make it less wrong than it is at the moment.

If you could cc the chambers taking into account the piston heights, it might work well, but to be honest, in my opinion, it's probably not worth the effort. (I wouldn't even know how to start working it out).

It depends how fussy you are and what is your intended use for the engine and vehicle. It can be made to run as well as you can without resurfacing the block, or you can bite the bullet and rebuild the motor into another block.

One requires a hell of a lot more work and $$$ than the other, and I suspect the end result may be imperceptable.

Lets face it, most people would have just bolted the head on, completely oblivious of the deck problem. the motor would have run and may not have even given any symptoms of anything being wrong.

An interesting conundrum for sure.

Mart.
 
3Dueces said:
Also,keep in mind that not only the bolt holes become "un-square" with the head gasket surface, the spot face for the bolt heads become "non-parallel" as well resulting in torque problems and leakage.
Click to expand...

Exactly, if they are intentionally angle milled for compression. We had a set that came on a roundy round car, sbc. They had taken so much off we had to use 2 spark plug washers and never could get the coolant to not leak around some of the head bolts.
 
Big-Foot said:
I would bring the short block to the machinist and have him back up your measurements of block height, then have the block decked to the lowest point measured. IE if cylinder 1 has a deck height of -.020" and cylinder 4 has a deck height of -.050" - have the block decked to -.018 ...
presumably the other side is similar.
Either way, you want to make your block deck parallel to the crank centerline.
This is how to do it right.
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To clamp a head to an angled block deck means that your head studs are not perpendicular to the block deck, the nuts will not provide a good seat on the heads.
Don't worry about quench / squish until you have a good foundation to work with.
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My opinions only...
Click to expand...

I know what you'r saying,..and I agree.
I have "bars" for the main saddles to check deck height,...you need a starting point..
 
You should not CC the heads (before or after milling) because of the angle of the head will make the numbers useless unless you take into account the piston popup variation from front to back.
The drawing is correct.
After the milling procedure the bolt holes will be correct and perpendicular to the crankshaft as they should be and the bolt head surfaces will be parallel to the bottom of the bolt head. If the surface of the bolt hole at the top of the head is scarred from the previous out of parallel situation, you may have them cleaned up when the angle milling operation is done. (skin first, then angle mill.) The next test will be back to the aluminum foil test to confirm you work. If the balls all turn out the same , then the combustion chambers are all equal and you will have satisfied Ol' Ron on his quench dimension. It will run great.
The angled block-angled head situation will be similar to a 409 or a VW VR6, instead of side to side, it is front to back.
My opinion
 
^^ Good points made there, Floyd. the bolt angles will be more correct after angle milling than they are now. Hadn't thought of that.

Mart.
 
The chamber volumes in the driver head are about equal now. After the angle milling, they won't be. Combined with the extra volume in the cylinders themselves (because of the pistons being lower in the bores), the total volume at TDC above the pistons should be close to the same.
 
OK, I was finally able to find someone to mill my head to my specifications. I went to five shops who either said they couldn't do it, or wanted an exorbitant amount. I finally found a retired guy running a shop in his backyard (ain't that always the way) who said "No problem". I got the head back and started working with it today. All of the measuring and checking I did before having it worked on paid off, because the results were better than I would have expected. I installed the head with a used gasket and put foil balls on the valves and on the pistons. I only put 3 balls on each piston (at 3, 6, and 9 o'clock) because this was a preliminary check. The first thing I found is that I have plenty of clearance over the valves, so there is no problem there. Next I checked the balls on the pistons. They were remarkably consistent for each cylinder, and the averages per cylinder were quite close. I could bore you with the details, but for brevity, here are the average clearance by cylinder :

#5 - .046
#6 - .050
#7 - .050
#8 - .052

This is about where I like to start when fitting heads to an engine. I will now remove the gaskets, bolt the heads back on, and use the "grease method" (I got from "CharlieNY") to finalize the chambers. Given the numbers I have, I don't think I'll have to remove over .005 of material from any area. It's always a tedious job, but the results are worth it.

In the final analysis, I believe that this was the proper way to solve this problem. Tearing the whole engine down and decking the block even more did not appeal to me. I will end up with good squish and consistent combustion chamber volume. Also, I am now sure that the head bolts are parallel with the bolt holes in the head. How I determined this is a little beyond the scope of this post. Anyone who wants the details can PM me.

In the final analysis, I am completely satisfied with the results of the process and I am sure I will end up with a fine running engine.
 

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I really appreciate the work you've done to BUILD an engine. Planing ahead leads to not only a fine running engine but one that will last for a long time. My 280 is one of the strongest engines I;ve ever built and has only one modified part in the engine .145 over pistons, along with .045 piston to head clearance a Gm dist by richard and a 2GC carb. The torque is un real. It was also the least expensive one.
 
In case anyone is interested in how this turned out, I have completed the assembly and have gotten the engine running. I am extremely happy with the way it runs. Granted, I have only break-in time on my engine stand, but everything works so well, that I can't help but think I found the proper solution. See for yourselves : https://www.youtube.com/watch?v=deAgpVmvjhU
 
An engine stand is the worst thing you can use for a new engine, because: It allows you to run the engine without a load. THis could glaze the cylinder walls and prevent ring seating. Put the darn thing in a car/truck and drive it like you stole it. Best engine stand is an old tire, and an oil pressure gauge..
 
I run all the engines I build in an engine stand after they are built. I run them enough to be sure there are no problems and I don't let them sit and idle. I have never had nor heard of a problem with any of these engines.
 
I was browsing "YouTube" and came across a video of a very high-end shop that was building a V12 Packard from scratch. You know the kind of place : white walls, tile floor, not a tool lying around, high ceilings, commercial lighting etc, etc., etc. The kind of place I couldn't afford to even walk in the front door. They finished the engine, and I must say, it was a work of art. The guy narrating the video said they then ran the engine (at varying speeds) on the stand for twenty hours for break in. Only then do they transfer it to their dyno for load testing.

I personally couldn't bring myself to do the initial start of a fresh engine sitting on an old tire with no cooling or instruments. I want it on my stand with everything connected (up to and including the dual A/F meters). I fully believe that the potential for damage to an engine is much higher with a impromptu start on a tire than it is with a controlled planned start on an adequate stand. I have also heard that after a successful initial start, an engine should be run at 2000 RPM for at least 20 minutes to break in the cam. So, it seems I must make a choice of risking my camshaft or my piston rings. Since I personally know folks who have had their cams go flat, but nobody with an unseated set of fresh rings, I'll go with the stand. Anyway, haven't I been reading (other places and even here) that modern rings break in in a minute or so? I think "Ol' Ron"s concerns may have been valid back in the old days with"chrome rings", but in this day and age, I think I'll stick to my engine stand.

In any event, it was run for less than 1/2 hour because I need my stand for my Olds Rocket initial start-up.
 
Ford broke in the babbit bearing motors by running them with an electric motor until the current decreased by a certain amount. I agree with Ron about having a load to seat the rings but it takes a lot to glaze the cylinder walls.
 
I guess I was being alittle crude when I suggested the old tire, it's a junk yar thing of my youth. The problem I have with an engine stand is: Once you have it there, you might consider running it just to impress your friends while you build up the car to put it in. This might take a few years and by that time the engine is all warn out from
No load running"
Bearings, that have been properly fit, need little or no break in time. And some new style rings and honing break in rather quickly. Not many of use them. At one time I had a dyno with all the bells and whistles. inital start up was check for oil pressure and leaks. I brought the rpm up to 2000 rpm and brought a load in to drop the rpm to 1500. Left it there untill I got some tempature in the engine and started increasing the load to about 100 ft/lbs at 2000 RPM and then shut it down. The next day retorque the heads and fire it and play with it for awhile with tuning the carb and ignition. call the customer to pick it up.
But an old tire is better than an engine stand, as it won't hurt the rngine.
 
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