How good are bigger built engines?

andreic · 11-08-2015, 06:29 PM

Hello fellow 914-ers,

I have the option to buy a 914 engine which was rebuilt by a local reputable shop (Mofoco in Milwaukee). The engine started out as a 2.0L, but it was rebuilt with a stroker crank (82mm), matching rods, brand new heads, and 103mm cylinders and pistons. A new, larger oil sump was added. The engine supposedly has zero time (was run for maybe one hour total). From the looks of it this is accurate.

I have not yet seen the motor up close, but I am a bit weary about the very large displacement (the 82mm crank and 103mm pistons bring the displacement to 2733cc). I worry it may not be able to cool off well, and/or be unreliable in other ways. Is this a concern? Or these motors are known to hold up well all the way up to this size?

I don't plan to use the motor for anything crazy -- I don't race, I only use the car as a week-end driver on nice days. Of course, I'd like to have extra power (my current 1.8L is a bit tired), but I would not want to sacrifice reliability much.

Thanks for your opinions. Andrei.

John Rogers · 11-09-2015, 05:05 AM

Having raced a 2.8L big four for several years, they are not worth all the trouble and expense you will have. To make it last even for street use you'll need a dry sump system and increased air cooling such as a 911 type alternator/fan shroud. You did not mention what head work was done, what cam is inside and what lifters were used. Unless lots of $$$$ was spent on the heads to flow them well, it will run terrible as there will be very low flow.

Last of all, what intake comes with it as I used Weber 48's and it took several trips to the dyno shop to get the jetting set right so the engine will not burn up.

In the long run, it is a much better plan to start saving and gathering for a six conversion.

Mark Henry · 11-10-2015, 07:34 PM

I wouldn't be quick to call Mofoco a reputable shop when it comes to engine building, especially a type 4 engine.
They are known to cut a lot of corners to make a big engine, incorrect parts combinations, lower quality parts, questionable machining practices ...etc...
I have more into my piston and cylinder set then they have in the whole engine.

Quote:

...but I would not want to sacrifice reliability much

Right there would be the point at saying this is the wrong engine for you.
Build a 2056cc, if you have the FI system it can be made to work or if it's carbs get a mild carb cam

porschetub · porschetub's Garage

Yea listen to Mark he knows,an engine like this could be a heap of trouble as John mentioned from experience.
Any decent increase in capacity such as the one you are mentioning comes with an issue more than $$$,trying to keep it cool enough is the primary concern,a good front mount cooler system done correctly will help....only if its done right.
What price have they quoted to build it?
The 103 mm piston barrel combo's have in the past had a questionable reputation,I don't think anything has changed much?.
On 914world the 2056 seems to be a very good combination and many guys on there are running them with good results....I see this as a good recomendation.

mb911 · mb911's Garage

Not that I can contribute much but I am picking up a complete 1.8 this weekend that maybe a good base for you to build a bigger engine off of and do it yourself . They are not the most complicated engine to learn on.. I am just down the road from you as well

porschetub · porschetub's Garage

Quote:

Originally Posted by mb911

Not that I can contribute much but I am picking up a complete 1.8 this weekend that maybe a good base for you to build a bigger engine off of and do it yourself . They are not the most complicated engine to learn on.. I am just down the road from you as well

No they aren't a complicated engine but as with any you need to know what to look for,cylinder heads for example are the weak link and must be overhauled by someone that knows these engines.
Attention to detail during overhaul is the difference between a strong good running build or a disappointing clonk later on

Dave at Pelican Parts · Dave at Pelican Parts's Garage

The 1.8 heads are at least stronger than the 2.0 ones. They aren't quite as good for power, but I think they make up for that in strength. I think the 1.7 heads might be stronger yet, and I have heard that the Vanagon "square port" heads have even more material in the exhaust port to work with. (But they have tiny little valves, so they need more work too!)

--DD