2270(or so) Build |
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2270(or so) Build |
yeahmag |
Jan 8 2021, 12:47 PM
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#1
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
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? |
914werke |
Jan 8 2021, 03:21 PM
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#2
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"I got blisters on me fingers" Group: Members Posts: 9,998 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
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 |
Jan 8 2021, 03:35 PM
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#3
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
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 |
Jan 8 2021, 08:35 PM
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#4
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Senior Member Group: Members Posts: 1,541 Joined: 8-August 10 From: Claremont, CA Member No.: 12,023 Region Association: Southern California |
Will definitely be following this thread. (IMG:style_emoticons/default/popcorn[1].gif)
Which cylinders will you be using? |
wndsrfr |
Jan 8 2021, 09:03 PM
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#5
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Senior Member Group: Members Posts: 1,428 Joined: 30-April 09 From: Rescue, Virginia Member No.: 10,318 Region Association: MidAtlantic Region |
FAT uses new forgings & will supply you with a flywheel doweled with 5 pins...hard to beat.
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Alapone |
Jan 8 2021, 09:57 PM
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#6
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Member Group: Members Posts: 105 Joined: 4-April 13 From: Nj Member No.: 15,734 Region Association: None |
Definitely following this.
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yeahmag |
Jan 8 2021, 10:17 PM
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#7
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
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 |
Jan 8 2021, 10:34 PM
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#8
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Senior Member Group: Members Posts: 1,541 Joined: 8-August 10 From: Claremont, CA Member No.: 12,023 Region Association: Southern California |
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914werke |
Jan 8 2021, 11:05 PM
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#9
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"I got blisters on me fingers" Group: Members Posts: 9,998 Joined: 22-March 03 From: USofA Member No.: 453 Region Association: Pacific Northwest |
I used them on a 912E rebuild but that was only 2056
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groot |
Jan 9 2021, 10:22 AM
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#10
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Dis member Group: Members Posts: 894 Joined: 17-December 03 From: Michigan Member No.: 1,444 |
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 |
Jan 9 2021, 11:15 AM
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#11
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Member Group: Members Posts: 268 Joined: 15-November 19 From: Happy Place (& surrounding area) Member No.: 23,644 Region Association: None |
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. |
yeahmag |
Jan 9 2021, 12:01 PM
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#12
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Advanced Member Group: Members Posts: 2,421 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California |
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Mark Henry |
Jan 9 2021, 02:08 PM
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#13
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
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. |
groot |
Jan 9 2021, 03:58 PM
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#14
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Dis member Group: Members Posts: 894 Joined: 17-December 03 From: Michigan Member No.: 1,444 |
AA crank, chevy journals... this is kind of a parts bin engine to get the car dialed in.
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Dave_Darling |
Jan 9 2021, 07:02 PM
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#15
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914 Idiot Group: Members Posts: 14,981 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
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 |
Mark Henry |
Jan 9 2021, 08:48 PM
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#16
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
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. |
Montreal914 |
Jan 9 2021, 11:02 PM
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#17
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Senior Member Group: Members Posts: 1,541 Joined: 8-August 10 From: Claremont, CA Member No.: 12,023 Region Association: Southern California |
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? |
Mark Henry |
Jan 10 2021, 07:59 AM
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#18
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
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? 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." |
groot |
Jan 10 2021, 10:04 AM
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#19
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Dis member Group: Members Posts: 894 Joined: 17-December 03 From: Michigan Member No.: 1,444 |
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? |
Blown59 |
Jan 13 2021, 10:55 PM
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#20
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Member Group: Members Posts: 66 Joined: 21-July 19 From: St Louis Member No.: 23,315 Region Association: None |
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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