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Mark Four turbo build thread
https://slantsix.org/forum/viewtopic.php?t=64567		 Page 1 of 2
Author:  MadScientistMatt [ Mon Mar 02, 2020 9:52 am ]
Post subject:  Mark Four turbo build thread
Although this is the fourth turbo combination I've run, it's my first engine rebuild. Thanks to coconuteater and Charlie S for donating several parts, and also to the others who'd offered to help. Today this build got started with dropping the parts off at the machine shop. One BH code block:
Attachment:
File comment: One BH-code block
block at machine shop.jpg
block at machine shop.jpg [ 48.51 KiB | Viewed 8633 times ]
And two small torque converter cranks:
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File comment: Two small torque converter cranks
cranks at machine shop.jpg
cranks at machine shop.jpg [ 41.91 KiB | Viewed 8633 times ]
Author:  Greg Ondayko [ Mon Mar 02, 2020 11:59 am ]
Post subject:  Re: Mark Four turbo build thread
Matt, I would Highly recommend the Oiling system mods Doc Proposes in this document.

http://www.slantsix.org/articles/dutra- ... blocks.htm


Happy building and boosting. - with the Power and tunability ( ability to make more power) that you will infuse onto the slant you will want those parts to be skookum as frig!


Happy Building and Boosting!

Greg
Author:  MadScientistMatt [ Thu Mar 19, 2020 8:42 am ]
Post subject:  Re: Mark Four turbo build thread
No progress this week as I'm working from home and the car's at the shop at work. But last week I got a few pictures of doing Doc's water pump block mod. I know, should have done that before taking it to the machine shop, but better late than never!

Image

This block had a big ridge in the water pump cavity.

Image

Let's make some sparks.

Image

The final result.
Author:  MadScientistMatt [ Mon Mar 30, 2020 1:26 pm ]
Post subject:  Re: Mark Four turbo build thread
I tried to use some grease to keep debris out of the oil galley while doing Doc's oil galley porting mod.

Image

It did not work quite as I had hoped.

Image
Author:  Dart270 [ Mon Mar 30, 2020 2:08 pm ]
Post subject:  Re: Mark Four turbo build thread
Ouch. I always take some time and do all my grinding and dirty prep before I take the engine to the shop to get cleaned up and machined. You can do grinding afterwards before assembly, but it's a pain to clean everything...

Lou
Author:  Greg Ondayko [ Mon Mar 30, 2020 5:55 pm ]
Post subject:  Re: Mark Four turbo build thread
Blast that clean with brake cleaner and pipe brushes before assembly!


Greg
Author:  MadScientistMatt [ Tue Mar 31, 2020 7:26 am ]
Post subject:  Re: Mark Four turbo build thread
No, it's not blood. Just looks like it. :)

Already hosed it down with brake cleaner, will try cleaning it with a gun cleaning patch as well before starting.
Author:  DadTruck [ Sun Apr 05, 2020 7:33 pm ]
Post subject:  Re: Mark Four turbo build thread
Matt, did you get that painted red block from Cocanuteater?
If so I think I recognize it as one of the slants that he picked up from me in Indy.
He drove up from GA to get it.
If it is the same motor, I pulled it from a rusted beyond repair D150 that was headed for the crusher.
That may have been in 2010, or so.
Always good to see a motor that was saved going to good use.
One more thing,,IIRC, that slant was in front of a a833 od transmission, so the crank is drilled / sized for a pilot bushing, there should be one in it,,
But that has been along time ago and I could have it wrong,,
Author:  DadTruck [ Sun Apr 05, 2020 7:34 pm ]
Post subject:  Re: Mark Four turbo build thread
Matt, did you get that painted red block from Cocanuteater?
If so I think I recognize it as one of the slants that he picked up from me in Indy.
He drove up from GA to get it.
If it is the same motor, I pulled it from a rusted beyond repair D150 that was headed for the crusher.
That may have been in 2010, or so.
Always good to see a motor that was saved going to good use.
One more thing,,IIRC, that slant was in front of a a833 od transmission, so the crank is drilled / sized for a pilot bushing, there should be a pilot bushing in it,,
But that has been along time ago and I could have it wrong,,
Author:  MadScientistMatt [ Mon Apr 06, 2020 5:09 am ]
Post subject:  Re: Mark Four turbo build thread
Yes, I picked up the block (and rods) from Coconuteater. But it's being paired with a small torque converter flange crank so I can keep my current transmission.

It turns out the block had already been bored 0.030" over. But the pistons had some seriously weird damage to their tops - maybe detonation pitting, but it looked like they'd been damaged by something else. I could almost have done a hone and reuse job if I'd trusted the pistons not to crack, but instead I decided to have the block taken to 0.040" oversized.
Author:  DadTruck [ Mon Apr 06, 2020 10:50 am ]
Post subject:  Re: Mark Four turbo build thread
There was a teen age boy hanging around the area, I gave him a few bucks to help me pull
the motor. He had already hot wired the engine and had a fuel supply rigged out of a pop bottle and had started the motor a few times. I had heard it run. The carb was open with no air filter or housing so it easily could have ingested something..
Interesting find on the block being overbore, the engine was a combination of non matched parts.
Head was blue, the block red, oil pan black,,,, but I knew it ran,,,
And now it will run again,,that is great!
Author:  Dart270 [ Mon Apr 06, 2020 11:46 am ]
Post subject:  Re: Mark Four turbo build thread
Strongly suggest boring to 0.060" over.

Lou
Author:  DadTruck [ Mon Apr 06, 2020 11:49 am ]
Post subject:  Re: Mark Four turbo build thread
Agree, the .060 over bore is enough to actually de shroud the valves,
Although anything helps.
Author:  MadScientistMatt [ Tue Apr 07, 2020 12:22 pm ]
Post subject:  Re: Mark Four turbo build thread
Unfortunately, I've already got the pistons and the machine work done. This will let me save the 0.060" overbore if I end up with a Mark Five built with custom forged pistons and 198 rods, though. :) I'm a bit surprised that a 0.010" difference between the valve and cylinder wall would change flow so much; my thinking was that a little extra wall thickness would help with ring seal.

I am using stock valves but plan to do a bit of bowl work and a 3-angle valve job on the head before re-installing it.
Author:  DadTruck [ Tue Apr 07, 2020 5:05 pm ]
Post subject:  Re: Mark Four turbo build thread
Quote:
I'm a bit surprised that a 0.010" difference
just going .020 over probably helps, so .040 over helps more,, .060 a little more
David Vizard has a clearance where the bore no longer influences the air flow,,
I will see if I can find that.
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