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Twiggy - Long Rod Aluminum Block Engine Build-up
https://slantsix.org/forum/viewtopic.php?t=23948		 Page 24 of 25
Author:  Doc [ Fri Oct 17, 2008 1:45 pm ]
Post subject: 
Yes, I pulled the intake valve out of chamber # 5 to get a look at the valve seat insert and port pocket, everything looked OK there.

A couple of other observations on the head:
I saw (now remember) that I used the short valve stem umbrella seals on both the intake and exhaust valves... I was concerned about getting lots of oil into the aluminum (no guide insert) intake valve guide. I will change those back to the correct "long skirt" umbrella stem seals before this head goes back into service.

As for those aluminum intake guides... yes, they show some looseness and wear for the short amount of run time on them. Once I have a chance to check all the intake guides, I will have to decide if i am going to put liners into all the intake valve guides.

Now that this head is "out of service"... I can't help but think about freshening it up and installing it onto the Buster engine. :shock: :roll:
DD
Author:  440_Magnum [ Fri Oct 17, 2008 3:45 pm ]
Post subject:  Re: The Head Is Off...
Quote:
The only obvious thing is that this casted-in top deck on this engine has shifted and in places, it is being pushed down deeper into the block's water jacket. You can see seam lines and cracks in various places of the closed deck and some areas are now .005 to .008 lower. :evil:

Image

Live and learn... I did this block repair over 10 year ago, while I was doing the Hyper-Pak reproduction project... basically, took a badly corroded aluminum block to the foundry one day, sandblasted all the corrosion, fill the water jackets with casting sand, leaving 1 inch at the top to pour-in molten aluminum. In hind sight, the small amount of draft in the die casting, combined with the corrosion pits and some welding is not enough support for the new top deck.
Well, poop.

I wonder if you had drilled the block at numerous places, inserted dowels through the holes, and then poured your fresh aluminum around the dowels if that would have held it in place? Or even done it post-pour by drilling and tapping and inserting a number of bolts (pre-pour would be better to my way of thinking simply because you could use aluminum dowels and avoid dissimilar metal expansion problems).
Author:  75duster [ Thu Feb 26, 2009 6:51 pm ]
Post subject: 
just took the time to read this entire post (very very good reading). how did the coatings on the pistons hold up?
Author:  Wizard [ Fri Feb 27, 2009 7:08 am ]
Post subject: 
Not very good idea to run valve stems on raw aluminum for valve guides. Metal is soft and tremedous pounding that valves stems imparts on these guide. Sleeve them with valve guides. (bronze or iron guides which chrysler used on 2.2/2.5 alum heads with iron guides).

Cheers, Wizard
Author:  Doc [ Fri Feb 27, 2009 9:14 am ]
Post subject: 
The "heat barrier" coating on the tops of the pistons did flake-off in a few spots but most of it in now under a coat of carbon. I have not pulled the pistons out so I don't know how much of the skirt coating is left. I did tear-down a race engine that used this coating and all of the skirt coating on any high spots was gone.

As for the aluminum head... yes, the intake guides will get some bronze liners before that head goes back into service.

My current plan is to get my "Buster" engine block back from the machine shop and then use most of Twiggy to build-up Buster. (Light rotating assembly engine build)
DD
Author:  jason white [ Fri Feb 27, 2009 9:23 am ]
Post subject: 
I like all the great info and advice you give doc I am getting a 1980 slant6 out of a volare to rebuild and eventually put in my truck I am thinking about your 260inch engine as a possible plan if feasible
Author:  slantzilla [ Sat Jan 06, 2024 3:19 pm ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Just an update, Robert Maw on FB who is doing the billet heads has also done a billet deck plate. Not sure how he's mounting it in the block but from the pictures I've seen it sure is purty.
Author:  hyper_pak [ Sun Jan 07, 2024 7:50 am ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Zilla, If I remember correctly he machined a step in the block top,
machined a thick plate,
pressed it in with some super duper adhesive compound.
Something like that.
Author:  slantzilla [ Sun Jan 07, 2024 7:55 am ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
I believe so. :D
Author:  Dart270 [ Sun Jan 07, 2024 11:29 am ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
That is exactly what I was thinking of doing. I bet it should work very well and allow you to make real power and save the head gasket. Hopefully the guy will actually get something running someday...

Lou
Author:  hyper_pak [ Sun Jan 07, 2024 1:47 pm ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Here is one picture:

Attachments:
Rob Maw Block Mod 1 s.JPG
Rob Maw Block Mod 1 s.JPG [ 77.12 KiB | Viewed 840 times ]
Author:  Dart270 [ Sun Jan 07, 2024 2:25 pm ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Cool, thanks. That is perhaps better or at least more elegant that what I was thinking. Mine would be easier to make. I think you could just mill the outside of the block down about 1/8", then make a flat plate that would slip fit around the cylinders (maybe with a light "trace" around each cyl liner with a CNC mill after locating the center of each bore) and be sandwiched between the head and block. The plate would have head bolt holes and would look just like the bottom of a cyl head but with bores that would fit the OD of the cylinders.

Lou
Author:  Maxwedge413 [ Wed Feb 07, 2024 4:49 pm ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Quote:
Here is one picture:
A very neat piece - I had entertained doing something similar for an aluminum block I have had kicking around for years with a bad chip at the deck

(apologies - newb here)
Author:  hyper_pak [ Wed Feb 07, 2024 5:42 pm ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Quote:
Quote:
Here is one picture:
A very neat piece - I had entertained doing something similar for an aluminum block I have had kicking around for years with a bad chip at the deck

(apologies - newb here)
Maxwedge413, Welcome on board!
That block was super nice.
He milled the top of each cylinder so it had a step on the inside and on water jacket as well.

Make sure you come back!
Author:  Maxwedge413 [ Wed Feb 07, 2024 6:28 pm ]
Post subject:  Re: Twiggy - Long Rod Aluminum Block Engine Build-up
Quote:
Quote:
Quote:
Here is one picture:
A very neat piece - I had entertained doing something similar for an aluminum block I have had kicking around for years with a bad chip at the deck

(apologies - newb here)
Maxwedge413, Welcome on board!
That block was super nice.
He milled the top of each cylinder so it had a step on the inside and on water jacket as well.

Make sure you come back!
Much appreciated - is there a link to this gent's FB page?
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