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[email protected]
Samba Member
Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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 Posted: Fri Jul 08, 2022 2:10 pm Post subject: Crank rod journals |
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OK so I was rambling the Internet for some connecting rod ideas and found some rods that caught my eye honda 750 connecting rods down fall is that they are to short for my 36hp 74mm porsche crank I'm thinking of just having custom rods made .. but also some may say OK what's your point and why did those honda rods catch your eye ..they caught my eye because I'm looking for rods that can clear the cam lobes as much clearance I can get and have and if anyone here knows 74mm crank in a 36hp case is a bigg problem most 36hp guys and 356guys would have their journals cut down for chevy rods or honda 45mm journals to get as much clearance so that they could use a bigger lobes ..well these honda 750 rod journals I believe from what I searched up are 36mm   How safe would it be to go that small ..honda 750 racers use a strocker 69mm crank with those jounal sizes and they seem not to have problems ... I know crazy .... |
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3668
Location: Sarasota, in my adopted state of Florida
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| Posted: Fri Jul 08, 2022 2:29 pm Post subject: Re: Crank rod journals |
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Small rod journals in any flat four VW or air-cooled Porsche engine is not a good idea. Remember, almost all inline four-cylinder engines have a main bearing between every connecting rod, the flat four VW engine does not.
The VW crank will become weaker with a reduction in the size of main and rod bearings.
It will also become weaker when the stroke is increased. This is why VW engines need line boring so often.
Bigger mains and rods increase the cranks overlap making it stronger and more ridged.
Subaru solved this problem by using five main bearing to the VW's three.
If you want a significantly bigger engine, get a 1500/1600 engine that don't have the connecting rods hitting cam lobes.
Dan |
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Brian_e 
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Joined: July 28, 2009
Posts: 4104
Location: Rapid City, South Dakota
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| Posted: Fri Jul 08, 2022 3:06 pm Post subject: Re: Crank rod journals |
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Not sure if its possible, but what about having Jose build you a 36hp crank with 1600 size mains, then line bore the case to fit 1600 size bearings? Kinda like when T1 guys switch to T4 mains. The main journals would increase almost .200". This would really help with the journal offset of the smaller rod journals.
Just a thought.
Brian
_________________
So more or less the lazier and stupider you want to be, the nicer quality parts you need to buy.
-Modok
Narrowed beams, Drop adjustable spring plates, Bus disk brake and IRS kits.
www.type-emotorsports.com
Type E Engine Parts and Supplies
https://type-emotorsports.com/collections/engine-parts |
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Brian_e
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Joined: July 28, 2009
Posts: 4104
Location: Rapid City, South Dakota
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| Posted: Fri Jul 08, 2022 3:12 pm Post subject: Re: Crank rod journals |
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I just googled a honda 750 rod, and I don't thing the smaller diameter will be enough to still clear the giant nuts on the big end. Those nuts are exactly where a standard VW rod gets clearanced when building a stoker. Same reason a chevy rod wont work in a VW.
Brian
_________________
So more or less the lazier and stupider you want to be, the nicer quality parts you need to buy.
-Modok
Narrowed beams, Drop adjustable spring plates, Bus disk brake and IRS kits.
www.type-emotorsports.com
Type E Engine Parts and Supplies
https://type-emotorsports.com/collections/engine-parts |
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[email protected]
Samba Member
Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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| Posted: Fri Jul 08, 2022 3:23 pm Post subject: Re: Crank rod journals |
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| I've never thought about 1600 mains ..can it be done who knows but trust me I will ask around ...John willhoit builds 356 engines and has made/ makes a 84mm crank for his 356 engine cases and he uses honda journals what ones/size .. I don't know since he doesn't give his secrets out by what I was told ..I ain't trying to go that big but if that guy can with a 84mm 356 case ..I bet a 74mm can as well is it crazy yes is it safe most would say yes ...yes I know just get a 1500/1600 case ummm nooo I'm in love with the 36hp engines there unique to many 1776cc and 2387cc engines out there ..not many performance 36hp engines ..I have no problem with the 1600 performance I love them but I'm a 36hp /356 guy ..I'm in the process of building a 12valve 3 valve per cylinder head ...I gotta think outside the box but some times I can go over think things ... |
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3668
Location: Sarasota, in my adopted state of Florida
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| Posted: Fri Jul 08, 2022 3:29 pm Post subject: Re: Crank rod journals |
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| The Porsche solution was the one-piece rod cap. The 356/912 engine were hot rodded 36 hp engines. |
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[email protected]
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Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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| Posted: Fri Jul 08, 2022 3:29 pm Post subject: Re: Crank rod journals |
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| The rods I would have to make custom new ones with a bigger ratio length and 3/8 bolts or even 1/4 × 1.4 625 bolts but I would use the same honda 750 journal size ...new rods are mandatory since those rods have those big bolts that stick out and interfere and thos rods are 4.500 to short |
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Matthew
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Joined: January 29, 2004
Posts: 1760
Location: Eastern Tennessee
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67rustavenger
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Joined: February 24, 2015
Posts: 11298
Location: Oregon
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| Posted: Fri Jul 08, 2022 3:50 pm Post subject: Re: Crank rod journals |
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| Quote: |
| I'm in the process of building a 12valve 3 valve per cylinder head |
Say what?
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!
There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!
2003 Astrovan? GFYS again, Xevin! 
Don't let your bad ideas remain, ideas! |
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[email protected]
Samba Member
Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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| Posted: Fri Jul 08, 2022 3:58 pm Post subject: Re: Crank rod journals |
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| Matthew wrote: |
| What about the 36 hp rods that AA sells? |
To short "length" for a 74mm crank ....well to my liking and not much clearance also ...I've asked aapistons in the past for my 69.5 ww crank if they sold those aapistons 36hp h beam rods but with the smaller 1/4×1.4 625 rod bolts which are the same bolts that the porsche 356 h beam rods use and they sell as well .. aapistons told me no and were not willing to get the rods drilled or made from there manufacturer " China " to have them drilled for the smaller bolts 1/4x 1.4 which I didn't/don't understand why they couldn't since they have the same company who makes both the 36hp rods and 356 rods ...some folks just don't like asking there manufacturer to make a couple rods with smaller bolts I guess .... |
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[email protected]
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Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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| Posted: Fri Jul 08, 2022 4:04 pm Post subject: Re: Crank rod journals |
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| 67rustavenger wrote: |
| Quote: |
| I'm in the process of building a 12valve 3 valve per cylinder head |
Say what? |
Yes I am ...and it's gonna be a pushrod engine not ohc ..my dream engine is the porsche type 367 hemi I love that engine it's also know as the vw peter max muller engine ..I've got my idea from this engine 😍 ...
👇👇👇
https://youtu.be/JIkx0gzNumQ |
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[email protected]
Samba Member
Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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| Posted: Thu Jul 14, 2022 11:42 am Post subject: Re: Crank rod journals |
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| Brian_e wrote: |
Not sure if its possible, but what about having Jose build you a 36hp crank with 1600 size mains, then line bore the case to fit 1600 size bearings? Kinda like when T1 guys switch to T4 mains. The main journals would increase almost .200". This would really help with the journal offset of the smaller rod journals.
Just a thought.
Brian |
Talked to a couple of folks even Jose and 1600cc mains can't be done to a 36hp case only porsche 356 55mm mains can be done on 2 and 3rd main the porsche 356 main bearings are thinner ...but those porsche 55mm bearing are expensive compare to the 36hp and 1600cc..356 55mm bearings I've looked for pricing $400-500 no wonder vw 36hp guys are sticking to the stock 50mm bearings way way less for the bearings ....looks like I'll have to go for the 55mm porsche bearings just gonna be expensive 😡.. I wonder why porsche didn't make # 1 main bearing 55mm also ... |
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Dusty1
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Joined: April 16, 2004
Posts: 2190
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| Posted: Thu Jul 14, 2022 6:20 pm Post subject: Re: Crank rod journals |
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| [email protected] wrote: |
| OK so I was rambling the Internet for some connecting rod ideas and found some rods that caught my eye honda 750 connecting rods (truncated) |
You can get away with smaller rod journals if your crank has more support on the mains. For example recent Subaru flat fours have more main bearings than old VW flat fours. I haven't had my fingers inside a Honda 750 for decades but I suspect the crank is well supported in there.
| [email protected] wrote: |
| Matthew wrote: |
| What about the 36 hp rods that AA sells? |
To short "length" for a 74mm crank ....well to my liking and not much clearance also ...I've asked aapistons in the past for my 69.5 ww crank if they sold those aapistons 36hp h beam rods but with the smaller 1/4×1.4 625 rod bolts which are the same bolts that the porsche 356 h beam rods use and they sell as well .. aapistons told me no and were not willing to get the rods drilled or made from there manufacturer " China " to have them drilled for the smaller bolts 1/4x 1.4 which I didn't/don't understand why they couldn't since they have the same company who makes both the 36hp rods and 356 rods ...some folks just don't like asking there manufacturer to make a couple rods with smaller bolts I guess .... |
Saw Roger Waters in Boston the other night. Roger Waters understands why one- offs are one- offs almost as well as Chomsky...
Carrillo will make any connecting rod you're willing (and able) to pay for.
| [email protected] wrote: |
It's gonna be a pushrod engine not ohc ..my dream engine is the porsche type 367 hemi I love that engine it's also know as the vw peter max muller engine ..I've got my idea from this engine 😍 ...
👇👇👇
https://youtu.be/JIkx0gzNumQ |
It's so much better in German. I used to write punk tunes in German because it's way more bad- ass compared to English.
Bist du punk genug?
.
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esde
Samba Member
Joined: October 20, 2007
Posts: 6370
Location: central rust belt
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| Posted: Thu Jul 14, 2022 8:48 pm Post subject: Re: Crank rod journals |
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Have the rods and rod journals narrowed, and ask Jose to use a thicker counterweight. This way the crank throws can be made stiffer, the same idea as running Porsche journal rods on a 1600 based engine.
It'll be $$$, but there's no freebies when trying to squeeze a 36 for more juice.
_________________
modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that. |
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nsracing
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Joined: November 16, 2003
Posts: 9744
Location: NOVA
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| Posted: Fri Jul 15, 2022 4:43 am Post subject: Re: Crank rod journals |
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Using other rods will be in our future for the VW aircooled as we get less support for parts...and bearings and stuff.
I already got ready - got my crank grinder and crank welder. Coz it will not be long before we cannot find any bearings for rods and cases.
I have been collecting Porsche 911 rods to support my engine builds in the future. |
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Dusty1
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Joined: April 16, 2004
Posts: 2190
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| Posted: Fri Jul 15, 2022 5:59 am Post subject: Re: Crank rod journals |
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| [email protected] wrote: |
| I'm in the process of building a 12valve 3 valve per cylinder head ... |
Making one is a whole lotta work. You're going to need two...
| [email protected] wrote: |
| I gotta think outside the box but some times I can go over think things ... |
If you're making patterns for a one- off head you might as well make it fit 1600. That is unless you want an extremely labor intensive one- off.
I often think in terms of small batch manufacturing. When I make one of anything I generally pay for it. When I build ten more I hope to at least break even.
If you have all the time in the world and all of it is free...
Carry on.
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scotty timmerman
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3668
Location: Sarasota, in my adopted state of Florida
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| Posted: Fri Jul 15, 2022 1:20 pm Post subject: Re: Crank rod journals |
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Hey, thanks for the info on the type 367 engine. All the Porsche history I have looked at over many years and never knew about this one. Interesting engine. They did it before Chrysler.
Here is some more about the engine. Is a download and in English
http://www.downloads.izikastom.info/articles/REG-32-6.pdf |
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[email protected]
Samba Member
Joined: June 24, 2015
Posts: 882
Location: Rialto. CA
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| Posted: Fri Jul 15, 2022 3:19 pm Post subject: Re: Crank rod journals |
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| Dan Ruddock wrote: |
Hey, thanks for the info on the type 367 engine. All the Porsche history I have looked at over many years and never knew about this one. Interesting engine. They did it before Chrysler.
Here is some more about the engine. Is a download and in English
http://www.downloads.izikastom.info/articles/REG-32-6.pdf |
The type 367 in the video was/ is a 1.1 liter 64x75 it made 56hp the peter max muller type 367 had 4 solex 32 pbic carbs it was more powerfull than that one In the video I believe peter max muller type 367 engine made 60 to 70hp to remind you it was still a 1.1 litter monster the type 367 hemi was know as the powerfull engine porsche couldn't use for there 356s ....only 3 type 367 engines were build 2 are in running condition and the other last one is in a family collection I believe....not much is know about the type 367 but it's one nice bad engine ..imagine that engine build as a 1500 or 1600cc I wonder how much hp it would give with todays technology .....
Last edited by [email protected] on Fri Jul 15, 2022 3:52 pm; edited 1 time in total |
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Dan Ruddock
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Joined: October 25, 2012
Posts: 3668
Location: Sarasota, in my adopted state of Florida
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| Posted: Fri Jul 15, 2022 3:32 pm Post subject: Re: Crank rod journals |
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Not as much as the 4 cam furman 1500 engine 
I have built a 1904cc 356 engine that made a 140hp.
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