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moab Samba Member
Joined: August 28, 2013 Posts: 16 Location: Moab
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Posted: Tue Jan 21, 2025 7:41 pm Post subject: How to choose and engine |
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For a completely unrelated reason... I was wondering how to choose between the different engine sizes.
There are a lot of choices. Why not pick the biggest engine you can afford? Does reliability start to suffer the larger the bore or stroke goes? I would assume that if everything was equal the bigger the motor the more power it makes, the more power it makes the less you have to wring it out, all adding up to more longevity.
I have more experience with Chevy motors and if you try to make a 305 push a truck with a trailer it may explode whereas if you do the same job with a 632ci big block it will hardly notice it.
Matt
PS I assume that there is something I'm missing. |
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Glenn  Mr. 010

Joined: December 25, 2001 Posts: 78540 Location: Sneaking up behind you
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Posted: Tue Jan 21, 2025 7:45 pm Post subject: Re: How to choose and engine |
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Depends on the vehicle and your intended use.
Bigger is not always better.
Budget is always a limiting factor.
For example, Busses ruin hotter than Beetles, they also weight more.
Larger displacement doesn't always mean more power. You can build a 1600 that ill have more hp than a 2332. For example a 1600 with forged pistons and a turbo and a 2333 with stock heads, cal and very small carb.
Both can have 125hp. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare
עַם יִשְׂרָאֵל חַי |
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BFB Samba Member

Joined: November 03, 2014 Posts: 2205
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Posted: Tue Jan 21, 2025 7:51 pm Post subject: Re: How to choose and engine |
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+ old vw “ common knowledge” like if you dont go with thick walls the engine will melt down and that strokers wont last long.. etc _________________ Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1 |
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johnnyvw164 Samba Member
Joined: July 27, 2020 Posts: 598 Location: South of Raleigh
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Posted: Tue Jan 21, 2025 8:01 pm Post subject: Re: How to choose and engine |
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Lot's of factors. Piston sets are typically made for either 69 mm or 82 mm strokes. In between sizes require extra work. AFAIK, 74mm stroke is the largest you can use without clearancing the inside of the case. 1776, 1835, 1914 are the "easy" builds because there is (theoretically) less fitting to do as they are based on the stock 69mm stroke. Of course if you buy a complete engine kit from say, CB Performance, I guess those would already be clearanced.
The old saying..."speed costs money, how fast do you want to go". |
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Glenn  Mr. 010

Joined: December 25, 2001 Posts: 78540 Location: Sneaking up behind you
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Posted: Tue Jan 21, 2025 8:04 pm Post subject: Re: How to choose and engine |
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johnnyvw164 wrote: |
AFAIK, 74mm stroke is the largest you can use without clearancing the inside of the case |
I thought that until I installed a EMPI 69mm CW crank and found that it hit the case.
johnnyvw164 wrote: |
The old saying..."speed costs money, how fast do you want to go". |
CHEAP - FAST - RELIABLE
You can only have two of the above. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare
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modok Samba Member

Joined: October 30, 2009 Posts: 27301 Location: Colorado Springs
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Posted: Tue Jan 21, 2025 8:28 pm Post subject: Re: How to choose and engine |
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moab wrote: |
Why not pick the biggest engine you can afford? Does reliability start to suffer the larger the bore or stroke goes? I would assume that if everything was equal the bigger the motor the more power it makes, the more power it makes the less you have to wring it out, all adding up to more longevity.
PS I assume that there is something I'm missing. |
the main thing you are missing is the transmission.
Most of the popular engine combos the small CC engines are undercammed and the big CC engines are overcammed, to match common gearing.
If you can actually afford to fix the gear ratios that opens up a lot more good possibilities. |
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moab Samba Member
Joined: August 28, 2013 Posts: 16 Location: Moab
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Posted: Tue Jan 21, 2025 9:26 pm Post subject: Re: How to choose and engine |
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All of this makes sense. It's kind of what I suspected but I wasn't sure. Most things have compromises the sizes with the least compromises or the ones that you are willing to live with get chosen the most.
Thanks, Matt |
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johnnyvw164 Samba Member
Joined: July 27, 2020 Posts: 598 Location: South of Raleigh
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Posted: Wed Jan 22, 2025 4:17 am Post subject: Re: How to choose and engine |
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@Glenn; shows there's always an exception to every rule.  |
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Glenn  Mr. 010

Joined: December 25, 2001 Posts: 78540 Location: Sneaking up behind you
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Posted: Wed Jan 22, 2025 4:46 am Post subject: Re: How to choose and engine |
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johnnyvw164 wrote: |
@Glenn; shows there's always an exception to every rule.  |
Don't make the same mistake I made.
I had to tear a new engine apart to clearance the case because I assumed. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare
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