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Esoteric question re: aluminum slant six block compatibility
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Author:  Greg Ondayko [ Fri Feb 28, 2020 4:01 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
Quote:
Al block question....can an al 225 block be cut down to make a 170 block? If it would work, that might be a way to use an al block with bad corrosion around the top of the cylinders. I don't have one, just thinking.
This would sure be an interesting Idea.

Depends on the way the Die cast is made in my opinion.

I thinks the only way to know for sure is to try it out.

If there are dowel locating pins on THE AL block there will need to be some provison for those after cutting.
Also if the female threads for the head bolts get "cut away" in this process then I suspect your project might be D.O.A..

I have cut the tops off of cracked 225 Iron Blocks to make a honing plate say ~1-1.5 from the top of the deck. and it cut the thread housing for the head bolts with it - THis also might happen in your idea. If so, then you need another method of holding the head in place!


Greg
Author:  Dart270 [ Fri Feb 28, 2020 4:26 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
The block casting bosses for the head bolt receiving holes only go down about 1.5", so this will not work w/o welding on new bolt hole bosses. You can maybe cut it down 0.250" or so without getting into trouble.

Lou
Author:  hyper_pak [ Fri Feb 28, 2020 9:22 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
Quote:
Quote:
You can use a 75 up head on any slant (ex hydraulic)
Ex (I assume you mean "except") hydraulic…? Why?
I don't know anything about a hydraulic motor, don't want to say something I know nothing about.
My comment wasn't that it would not work, I just don't know.
Author:  hyper_pak [ Fri Feb 28, 2020 9:33 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
As far as cutting a 225 AL block down, that is an interesting idea. (Rob, I want that one I sold you back!) However the bolt issues have been mentioned. And there are those who don't have any interest in losing any cubic inches. If you were going to drop in the 198 crank, remember the crankcase needs some clearance on a steel block, also in the AL? There are the same issues with the normal AL block to deal with also, head gasket, bores moving around with higher power levels, 40 thousand overbore, rare block to find, bolts or studs, etc.

When they were de-stroking the 426 hemis in the 70s and 80s, they had started using low block 383s and adding 8 bolt bosses in the lifter valley. So, most anything can be done, limits are imagination, skills, cash, time and desire. Few slant folks have "all" those.

Great idea though!

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De-stroked Hemi s.jpg
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Author:  sixinthehead [ Fri Feb 28, 2020 2:21 pm ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
I like the idea of saving some of the otherwise 'decorative' blocks 8)
Even if they weren't making big power, it would still be a point of pride.

Maybe some of the shorter modern pistons on 225 rods & crank would allow you to mill the block enough to get past the corrosion without compromising the bolt bosses.
For that matter, most of the stock pistons were pretty far down in the hole to begin with - I wonder how much could be safely milled off a stock crown?
Author:  SlantSixDan [ Fri Feb 28, 2020 3:25 pm ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
Friends and neighbours, take a quick glance at the block. Or a picture of the block. Or a bad photocopy of a picture of the block, without your glasses and with your strong eye closed and with the lights dimmed. Or take a look at Lou (Dart270)'s correct description of why the answer is no.

(Actually, the answer is yes, you can cut an inch off the aluminum block and wind up with a 170 block. It won't have even the minimal deck surface it started with, and you won't be able to mount a cylinder head on it or anything, but yes, it will be a 170 block.)
Author:  DadTruck [ Fri Feb 28, 2020 5:12 pm ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
Quote:
most of the stock pistons were pretty far down in the hole to begin with - I wonder how much could be safely milled off a stock crown?
I don't own an aluminum block, but that is an interesting concept to fix one that is un-useable due to corrosion. Perhaps it can be milled to bring to the top a cylinder bore surface suitable for sealing.
assuming the milling would be in the <.100 arena.
Author:  Greg Ondayko [ Fri Feb 28, 2020 5:15 pm ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
When I built the engine that is in my 69 dart I took .100" off of an iron block to bring the pistons closer to the head... using 225 rods and stock pistons.


I am not sure if that can be done on an AL block successfully but The experts will chime in.


Greg
Author:  Dart270 [ Sat Feb 29, 2020 3:40 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
0.100" would be no problem at all. Most corroded blocks have problems that go deeper than that, though. Again, from my measurements it looks like 0.2-3" should be doable. Finding a shorter piston is trivial with a piston catalog, and you lose no displacement.

Lou
Author:  Charrlie_S [ Mon Mar 02, 2020 4:46 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
I don't know if this is the case on the al slant six block. But I seem to recall (from back in the day) that most aluminum blocks had the top of the cylinder liner a little "proud" of the rest of the deck, to insure good sealing.
Author:  Greg Ondayko [ Mon Mar 02, 2020 7:28 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
I seem to recall from looking at the liners that they are fairly cylindrical and not a lot of extra material up top.

Greg
Author:  Dart270 [ Mon Mar 02, 2020 11:06 am ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
No "proud" cyl liners on any blocks I have looked at and measured...

After looking again, I think 0.120-0.140" might be OK for a max mill depth, but beyond that you will get rid of the large flat sealing surfaces are the outside of the block, esp on the plug side.

Lou
Author:  Reed [ Mon Mar 02, 2020 3:02 pm ]
Post subject:  Re: Esoteric question re: aluminum slant six block compatibility
What about applying a oxidation dissolving chemical such as "aluminum jelly" and then filling pits with one of those lauminum brazing products that melts with a propane torch? I am no metallurgist, or chemical engineer, nor have I ever even set eyes on an aluminum bnlocked slant six in real life. But if the conern is disintegration of the aluminum material due to oxidization and corrosion, it seems that there must be a chemical that will remove such corrosion and another material that can be used to full the voids. The repaired block could then receive a light milling to restore flatness.

Feasible? Or no?
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