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> 2270(or so) Build
yeahmag
post Jan 8 2021, 12:47 PM
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I'm starting to get the case(s) machined and inspected and parts ordered for my next generation engine. The car is mostly used for autocross.

78x96
96mm piston with 22mm wrist pin (stroker)
5.4" Type 1 Rod, 22mm wrist pin
WebCam 86b/86c
David Finch heads (from Len Hoffman many moons ago)
9.5:1 CR running on 91 octane pump gas
CB Dry Sump (heavily modified) or Thorsten Piper dry sump pump
Front mounted oil cooler

There are a few crank options out there now:

* DPR offset grind Type 1 journal
* AA Performance Forged Type 1 journal
* FAT Performance Forged Chevy journal

I've read about a few 80mm DPR cranks breaking, so I was planning on staying under 80mm as I like the car to be able to rev. I was considering Chevy journals for ease of assembly, but the two cranks I've read about breaking were 80mm/Chevy journals. Is there any new information on cranks out there? Any input on the config?
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914werke
post Jan 8 2021, 03:21 PM
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Following. Aaron interested in your approach to dry sump-ing the /4. I sold off the CB pump prior looking for a better solution.
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yeahmag
post Jan 8 2021, 03:35 PM
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I’ve been running the CB Pump successfully in my current motor. I did do a bunch of work to open it up though.
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Montreal914
post Jan 8 2021, 08:35 PM
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Will definitely be following this thread. (IMG:style_emoticons/default/popcorn[1].gif)

Which cylinders will you be using?
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wndsrfr
post Jan 8 2021, 09:03 PM
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FAT uses new forgings & will supply you with a flywheel doweled with 5 pins...hard to beat.
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Alapone
post Jan 8 2021, 09:57 PM
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Definitely following this.
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yeahmag
post Jan 8 2021, 10:17 PM
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I have NOS JE’s and AA cast iron cylinders that I got in a deal, but I’m thinking about trying AA’s biral cylinders.
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Montreal914
post Jan 8 2021, 10:34 PM
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QUOTE(yeahmag @ Jan 8 2021, 08:17 PM) *

I have NOS JE’s and AA cast iron cylinders that I got in a deal, but I’m thinking about trying AA’s biral cylinders.


Did ask in another thread if anyone was using Birals in a 2270, but no replies...
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914werke
post Jan 8 2021, 11:05 PM
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I used them on a 912E rebuild but that was only 2056
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groot
post Jan 9 2021, 10:22 AM
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I have a 80x96 with birals. It's only run on the stand, so I can't comment on the biral performance.
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Jack Standz
post Jan 9 2021, 11:15 AM
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QUOTE(yeahmag @ Jan 9 2021, 01:47 AM) *

I'm starting to get the case(s) machined and inspected and parts ordered for my next generation engine. The car is mostly used for autocross.

78x96
96mm piston with 22mm wrist pin (stroker)
5.4" Type 1 Rod, 22mm wrist pin
WebCam 86b/86c
David Finch heads (from Len Hoffman many moons ago)
9.5:1 CR running on 91 octane pump gas
CB Dry Sump (heavily modified) or Thorsten Piper dry sump pump
Front mounted oil cooler

There are a few crank options out there now:

* DPR offset grind Type 1 journal
* AA Performance Forged Type 1 journal
* FAT Performance Forged Chevy journal

I've read about a few 80mm DPR cranks breaking, so I was planning on staying under 80mm as I like the car to be able to rev. I was considering Chevy journals for ease of assembly, but the two cranks I've read about breaking were 80mm/Chevy journals. Is there any new information on cranks out there? Any input on the config?


My research lead me to use the forged stroker crank with VW journals because they're a little bigger, which (all else being the same) should be stronger due to slightly larger overlap. Downside is they seem to be getting harder to find.

With the VW journal, you can use the new Empi rods that are stronger and lighter: https://empius.com/products/empi-pro-series...5-16-rod-bolts/.

And I'm using type 1 tool steel lifters, which are durable and lighter.

Just my 2 cents which is probably worth about that much. Good luck with the project.



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yeahmag
post Jan 9 2021, 12:01 PM
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QUOTE(groot @ Jan 9 2021, 08:22 AM) *

I have a 80x96 with birals. It's only run on the stand, so I can't comment on the biral performance.

Kevin,

I assume it’s AA on the birals, what crank did you end up using?

Thanks!
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Mark Henry
post Jan 9 2021, 02:08 PM
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Longevity you want the 78mm with T1 rod journals, less crank flex with the bigger journals. I run DPR, you cant beat Swedish steel of the OE crank. China cranks have soft journals but I have used them in the 78mm/T1 rod, racing I'd likely tear down the block each season, where you might go longer with a welded crank.
80mm cranks flex, but there's no replacement for displacement, so if you have a big budget and you can afford engines go for it.
If you need the engine to last longer you want the T1 journal.

Clearanced CB rods stock T1 or 5.4"

I still prefer the EMW KB pistons.

Heads need dual springs, retainers, keepers and Manton pushrods.

9.5CR is really pushing it, I'd aim for 9.2-9.3CR.

I've used the same cam on several builds, you need reduced base circle. Big duration, good for carbs but almost no vacumm signal for a MAP sensor, so ITB FI has to run in AlphaN (TPS only), which is a pain in traffic but no issue on the track.

Issue with the dry sump pumps is the fan in the way. Personally I'd run a 30mm schadeck done full flow, steel cover, tuna can and a big accusump.

One of the best mods for a race car is a big ass pipe running air from the front end and dumping it into the fan.

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groot
post Jan 9 2021, 03:58 PM
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AA crank, chevy journals... this is kind of a parts bin engine to get the car dialed in.
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Dave_Darling
post Jan 9 2021, 07:02 PM
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Is the 78 stroke big enough to require a reduced base-circle cam? I think I remember that's right around where you start to need that.

--DD
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Mark Henry
post Jan 9 2021, 08:48 PM
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QUOTE(Dave_Darling @ Jan 9 2021, 08:02 PM) *

Is the 78 stroke big enough to require a reduced base-circle cam? I think I remember that's right around where you start to need that.

--DD

Both 78 T1 and the Chevy rod flavors need reduced base circle cam and mod rods. All because of one pesky cam lobe in the way.
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Montreal914
post Jan 9 2021, 11:02 PM
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QUOTE(Mark Henry @ Jan 9 2021, 06:48 PM) *

QUOTE(Dave_Darling @ Jan 9 2021, 08:02 PM) *

Is the 78 stroke big enough to require a reduced base-circle cam? I think I remember that's right around where you start to need that.

--DD

Both 78 T1 and the Chevy rod flavors need reduced base circle cam and mod rods. All because of one pesky cam lobe in the way.


Reduced base-circle cam OK, but do these types of rods also need rework?


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Mark Henry
post Jan 10 2021, 07:59 AM
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QUOTE(Montreal914 @ Jan 10 2021, 12:02 AM) *

QUOTE(Mark Henry @ Jan 9 2021, 06:48 PM) *

QUOTE(Dave_Darling @ Jan 9 2021, 08:02 PM) *

Is the 78 stroke big enough to require a reduced base-circle cam? I think I remember that's right around where you start to need that.

--DD

Both 78 T1 and the Chevy rod flavors need reduced base circle cam and mod rods. All because of one pesky cam lobe in the way.


Reduced base-circle cam OK, but do these types of rods also need rework?


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Yes, it's not a huge amount but there's still a bit of clearancing, if you buy rods from T4store this is already done. For chevy rod and 80mm you have way more rod clearancing to do than the T1 rod.
I use the CB rod for 78mm T1 and the SCAT rod for 80mm chevy.

Stroker cranks are a lot dry fitting, I often assemble an engine several times as I build. As I like to say "no two objects can occupy the same space at the same time."


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groot
post Jan 10 2021, 10:04 AM
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Hmmmm... I didn't have much clearancing required for the Chevy rods and 80mm crank, but it's the only stroker I've built. I took my time and checked it a lot. Time will tell if I did an adequate job ;-)

Chevy/Buick journals are smaller than type 1, so should require less clearance work?... maybe you're comparing the clearancing required for type1 rod with 78mm versus Chevy rod and 80mm crank?
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Blown59
post Jan 13 2021, 10:55 PM
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Curiously... As a noob when it comes to T4 builds... Why not run the 2.0 rod journal and not reduce the cam base? Isnt the crank strong enough and the reduced cam circle weakening the cam?

If my idea is wrong, can someone please educate me as to why?
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