My 72 barn find ( http://www.914world.com/bbs2/index.php?showtopic=275587&hl= ) is now starting to get a lot of work done so I can hopefully make it to lots of rallies next year. The car Has 50K original miles on a 1.7 that had some work on it previously making it a 1911 with Dlortos on it.
The engine is now torn down for rebuild with a little more power. I would like it to look as stock as possible but would like it to be a sleeper. I am considering 2.0 LTR FI and having everything else built. I am looking for suggestions on what you would do to the engine and why.
Thanks for the help
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The standard upgrades are:
1.7/1.8 starting point and you don't want to buy crank/rods/heads: Build a 1911.
2.0 starting point and you don't want to buy crank/rods: Build a 2056.
Any starting point and you're willing to spend some money: Build a 2270.
These are proven combinations that a lot of people run and you can get a lot of help 'designing' the engine and tuning. There are other combinations that come with drawbacks and compromises. Or there are things like forced-induction (turbo/super) but those aren't anything as easy as building a bigger motor.
I guess I maybe don't know the full meaning of the term, but when I think concourse car, I think of an original car, built to original specifications. Not something that's been cut up for flares with a swapped or modified engine. But again, I'll be the first to admit I sometimes don't know what I'm talking about.
For what it's worth, I've heard the 1911's are pretty dang peppy. That's what mine is, hope to have it driving next Spring. If you build the 1911 you'll probably keep the 1.7 heads/tins/specific bits and make it look the closest to it's original 1.7 setup.
Your 1911cc with Dells should be about as good as you can easily do. If there's nothing wrong with it, slap it back together and keep driving! Most especially if you are going to do an engine swap in the near to middle future, the cheap and easy way is likely the way to go.
For more power, you're looking at spending money that you won't get back. Either a nice cam and a bit of head work to wake up the 1911, or finding a 71mm crank and rods (and P&Cs) to make the 2-liter's 1971cc displacement, or a 2056cc. But the 2.0 heads are expensive, and your 1.7 heads would need a good bit of work to flow like those do.
If you can find a 2.0 engine complete with FI, that should be mostly a bolt-in. But those can be a bit hard to find with all of the bits on them.
Oh, a good exhaust like the Tangerine Racing header setup should provide a real boost in power; less-expensive headers will provide less of a boost and most mufflers aren't much improvement when using stock heat exchangers.
I do think the best option is freshening up the current motor (if it's apart) and just driving it.
--DD
71mm stroke is stock 2.0.
71mm x 94mm is 1971, which is the stock 2.0 size.
71mm x 96mm is 2056.
Stock 71mm crank and rods are fine for most builds, no need for fancy upgraded components.
If I were you, I'd look at a 1911, with a focus on lightening. Order of 'upgrades' by cost/benefit (in my opinion)
Core 1911 (what you've got now, your starting point)
Lightened flywheel.
New 96mm pistons and cylinders.
2.0 heads.
Valves/springs/retainers/pushrods for high RPM (lighter/stiffer).
Lightened connecting rods.
Lightened pistons.
I believe I've read a post on here by Jake Raby that the 1.7 heads are desirable because the smaller ports increases the velocity. I wish I could find it. Unfortunately the 1.7 heads combustion chamber/spark plug location are not as good as the 2.0 heads.
Glen, you're right about the velocity increase and that can have its advantages in certain engine designs. But it's really an aide to low-rpm power. If you build a bigger motor or a high revving motor those small ports will restrict the upper RPM band.
Like all engine design, it's just about what you want out of your engine.
Depends on how far down that list you're going to go. If you lighten everything, it'll rev higher and high revs benefit from more overlap. If you're not going to lighten as much you'll probably be happier with a cam with less overlap for better driveability and easier tuning.
I prefer most things about the 1.7 engine as a foundation for a larger displacement build- especially the crankcase.
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