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Tue Jan 21, 2025 7:41 pm

For a completely unrelated reason... :wink: 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.

Tue Jan 21, 2025 7:45 pm

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.

Tue Jan 21, 2025 7:51 pm

+ old vw “ common knowledge” like if you dont go with thick walls the engine will melt down and that strokers wont last long.. etc

Tue Jan 21, 2025 8:01 pm

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".

Tue Jan 21, 2025 8:04 pm

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.

Tue Jan 21, 2025 8:28 pm

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.

Tue Jan 21, 2025 9:26 pm

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

Wed Jan 22, 2025 4:17 am

@Glenn; shows there's always an exception to every rule. :roll:

Wed Jan 22, 2025 4:46 am

johnnyvw164 wrote: @Glenn; shows there's always an exception to every rule. :roll:
Don't make the same mistake I made.

I had to tear a new engine apart to clearance the case because I assumed.