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anthonimartini
Joined: 17 Feb 2020
Posts: 240
Location: portland oregon
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 Posted: Mon Mar 29, 2021 1:11 pm Post subject: |
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you would probably have enough tilt on the rod a bit past bdc to get your 11mm socket on them. but you do raise a good point that i didnt think of. on the aircooled engines i assemble the entire crank with rods in a stand and plop it down on the case half. im not entirely sure these rods will cut it anyways. im getting some sizing descrepencies on the big end bore. the 914 crank journals are 50mm std and ours are 48mm so im not sure a undersize bearing will work. i need to see what i can get bearing wise. i may be offset grinding my crank to use this rod but with a chevy journal. its getting muddied. i may end up just spending half a day lightening and balancing my stock rods. i just dont want to spend 250 bucks on rod bolts just to keep the stock stuff.
_________________
ive saved alot of 924's
current:
79 MochaSchwartz 931
83 944
87 924S
Instagram @anthoni.jpeg
formerly known as turbellion, lost password. |
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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| Posted: Mon Mar 29, 2021 1:16 pm Post subject: |
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| what is wrong with the bmw rods, why dont make them work? |
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anthonimartini
Joined: 17 Feb 2020
Posts: 240
Location: portland oregon
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| Posted: Mon Mar 29, 2021 1:51 pm Post subject: |
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the only problem with them is how narrow they are. im honestly not sure if its really a problem. i have read stuff arguing both sides. im considering getting my crank journals welded and machined narrower as to keep the rod to crank tolerance within spec. i need to talk to a my machinist about this first. hes built tons of race engines and id like to get his perspective on it. as a side note many of the aircooled motors i built were extremely loose there as well. but the bmw rods are over .100" gap.
_________________
ive saved alot of 924's
current:
79 MochaSchwartz 931
83 944
87 924S
Instagram @anthoni.jpeg
formerly known as turbellion, lost password. |
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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| Posted: Mon Mar 29, 2021 2:10 pm Post subject: |
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| anthonimartini wrote: | | the only problem with them is how narrow they are. im honestly not sure if its really a problem. i have read stuff arguing both sides. im considering getting my crank journals welded and machined narrower as to keep the rod to crank tolerance within spec. i need to talk to a my machinist about this first. hes built tons of race engines and id like to get his perspective on it. as a side note many of the aircooled motors i built were extremely loose there as well. but the bmw rods are over .100" gap. |
is welding the crankjournals and machining them expensive? |
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anthonimartini
Joined: 17 Feb 2020
Posts: 240
Location: portland oregon
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| Posted: Mon Mar 29, 2021 2:17 pm Post subject: |
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im not entirely sure yet.... probably. im hoping he tells me with confidence not to worry about the looser gap but i suspect that will not be the case. i also could consider using the nascar method of controlling the rod axial movement with spacers at the wrist pin but to do that properly is also kinda tricky and will involve getting rid any taper on the piston. i just wish those chinese companys would make us some rods!
_________________
ive saved alot of 924's
current:
79 MochaSchwartz 931
83 944
87 924S
Instagram @anthoni.jpeg
formerly known as turbellion, lost password. |
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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| Posted: Mon Mar 29, 2021 2:32 pm Post subject: |
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| gegge used washers sucessfully |
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anthonimartini
Joined: 17 Feb 2020
Posts: 240
Location: portland oregon
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| Posted: Mon Mar 29, 2021 2:59 pm Post subject: |
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ill have to ask him how he did it. he used vw flat tops correct?
_________________
ive saved alot of 924's
current:
79 MochaSchwartz 931
83 944
87 924S
Instagram @anthoni.jpeg
formerly known as turbellion, lost password. |
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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| Posted: Mon Mar 29, 2021 3:45 pm Post subject: |
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| anthonimartini wrote: | | ill have to ask him how he did it. he used vw flat tops correct? |
"No, I dont have any pictures of the washers. They were made of aluminium with a very tight 22mm clearence. Cant remember thickness or outer diameter." this is what he said to me
Last edited by Juho on Mon Mar 29, 2021 4:14 pm; edited 1 time in total |
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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motormouth
Joined: 28 Feb 2010
Posts: 118
Location: Canton
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| Posted: Tue Mar 30, 2021 1:12 am Post subject: |
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Mitsubishi rods from the 4G63 will work. They are slightly wider and smaller in diameter, so the crank has to be machined. Before I stalled out on my 924 project, I bought a set of rods and had my crank machined. It all seems to fit together fine, but haven't gotten the motor together yet.
With the Mitsu rods, you get a 21mm(??) rod which has far more piston options than the 24mm(??) 924 rods. |
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Juho
Joined: 03 Oct 2018
Posts: 377
Location: Finland
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| Posted: Tue Mar 30, 2021 2:57 am Post subject: |
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| finding pistons for mitsu rods is harder |
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motormouth
Joined: 28 Feb 2010
Posts: 118
Location: Canton
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| Posted: Tue Mar 30, 2021 3:46 am Post subject: |
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They’re 21mm. There were a lot of options I thought when I first started looking.
There’s a thread by ideola from a while ago on that topic. |
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anthonimartini
Joined: 17 Feb 2020
Posts: 240
Location: portland oregon
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| Posted: Tue Mar 30, 2021 3:41 pm Post subject: |
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sooooo i found this....
https://www.aliexpress.com/item/32782381728.html
they list they exact dimension we need for either a stock piston or a vw flattop.
im gonna order and see what happens. i recently ordered a brand new head for a japanese import toyota van i have from a similar alibaba seller and the part arrived within 2 weeks. ali is legit.
_________________
ive saved alot of 924's
current:
79 MochaSchwartz 931
83 944
87 924S
Instagram @anthoni.jpeg
formerly known as turbellion, lost password. |
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924 FAQ (Technical)
, these are min order only 6pcs