Hi everyone. While I don't own a 914 per se, I did play one on TV last weekend when I pulled its drivetrain for use in my 912. It's a 1.7, and I have a couple questions for the kind folks here.

1. I understand that the stock 1.7 made about 80HP, whereas the Super 90 in the 912 made around 92. I'd like to get around 10 more HP out of the 1.7, ideally without increasing displacement. I'll be running dual carbs. Is this a realistic goal, and if so what is the best and simplest way to accomplish it?

2. I have the dome top 1.7 pistons. These seem to be getting hard to find and were made by AA. I have run across a couple of online vendors that may still have old inventory hanging around. Is the quality of these pistons and cylinders any good, and if I can't find dome top pistons, is there an alternative that won't lower my compression ratio to VW Bus levels (ie keep it above ~8.2:1)

Thanks!

Check to see if your pistons are in spec, its possible to re hone the cylinders and use the original Pistons with new rings.

To get more power you will need to change to a carb camshaft and get a decent header for your setup.

You can easily beat the power of a super 90 by building a balanced, blueprinted, and properly designed 1.7 type 4 motor.

I'm...uh...not optimistic about the chances of re-using them

IMG_0086 by Tylinol, on Flickr

The leakdown must have been really good though, since the bottom end did not suffer any corrosion.

Haha,

Go to European Motor Werks in CA.
Get new pistons and cylinders
Get new AMC heads based upon the 1.8 liter motor, they have better air flow.
You are starting with maybe a case , the rest needs to be replaced.

Rich

What's your budget?

Like most projects I don't really have a hard number, but the more I can save on the engine without sacrificing quality the more I can put towards the rest of the car. To better answer that, I would be very pleased to get away with $2000 into a longblock. I'd like to have the 1.7 heads rebuilt rather than going with the new 1.8 cast since I've had good luck with my rebuilt 2.0 bus heads, and those heads have worked a lot harder. The jury's still out on if anything in the bottom end is usable - I'm doubtful given the state of the cylinders, but I'll reserve final judgement until the case is split.

From what I see, sell the motor for scrap and get something to work with. Even the case has lots of corrosion.

Heads are now cheaper to buy than get rebuilt...shop around.

Have to agree with Mark,find an engine that turns and has been stored inside out of the weather,personally I like the 1.7 and fitted with 96mm barrel set is a good combo and very popular on here.
You may be working hard to get a longblock together for that money however,depends on how long you want to run the motor really,good luck.

I have a 1.7 that puts out around 100hp with dual 40 Dellortos.
Valve train is built to take more than 6000 rpm.
Camshaft has increased lift and duration from stock, but I don't recall the specific camshaft used.
Compression increased to more than 9:1.
Ports re-worked to improve flow.
Tangerine 1 1/2" EVO header with EVO II Silencer.

The engine is in my street car, and has very mild manners.
I love to see the tach reach 6K before I shift.

Good to see another Nashville member. I have an old "spare" 1.8 liter, you are welcome to check out and see if you might want to start with it. @$250? The fella I got it from had driven the car around the block before he took it out. He scavenged a few things from it, but it will turn over by hand. I'll take some photos this afternoon.

Where are you located in Nashville? I am east in Mount Juliet. I would be willing to help you out any way I can, that includes weekend labor.

Clark

Whenever a HP number gets mentioned, you also need to consider what RPM it makes that power at. It's not difficult to break 100hp with a 1.7 if you're willing to rev to 7000rpm and you don't care if the car will barely move/run at 2000rpm.

Because of your budget, you are restricted to off the shelf parts. You can get custom JE pistons, but they're quite expensive. Reducing you combustion chamber volume may be the only option for raising compression ratio. As mentioned above, the choice of cam will make a big difference.

fify

Cool! I'm in South Nashville; if you frequent Cars and Coffee you may have seen my blue beater Alfa there at some point. I'm going to finish digging into this 1.7, and if the bottom end is indeed a lost cause then I will probably take you up on that 1.8!

RE power and RPM: It seems that 100hp is not too terribly difficult to extract from a 1.7, but roughly what would just a cam and a port/polish on the heads (plus appropriate carburation and exhaust) yield? My only real goal power-wise is that it not be noticeably slower than a stock 912.

Add HD single valve springs, and a small flycut on the heads (for compression) to the list and you'll get to 100.

I have a few 1.7s, and 1.8s that are complete and ready to rebuild. I'd be happy to sell you one, and I am not too far away (Charlotte).

I've got the case split now. Everything besides the pistons and cylinders are in great shape; better than the 2.0 in my bus. I suspect the engine ran just fine, and was relatively low-mileage, before sitting. A pleasant surprise.

But I was wondering if you could provide some more details on this. I'm sending them off to be rebuilt by Adran at headflowmasters soon, but I'm not sure exactly how to ask for a small flycut - do I give a target compression ratio, a number of millimeters to remove, etc? Any other bits of "language" I should know when sending the heads off?

Edit: I will (hopefully) be getting a set of 1.7 dome-top pistons in soon, if that matters.

If you are replacing the P&Cs anyways, why not just get a set of 96mm?

Your head guy ( ) will know how much to flycut them,it can't be too much from memory,I think you mean flat top pistons these are usually named "euro" pistons.
Just remember most cylinder head rebuilders run away when they see cracked heads,get them stripped and beadblasted before proceeding,any welding repairs required normally aren't good economy as opposed to getting good cores to begin with.
EMC should have the parts to get you to 1911cc(96mm) not a lot of point staying with stock barrels and pistons @ 90mm.
Good luck.

My thinking is that, given the cross-country mid-august death valley trek the engine faces, I'd like to keep as much material on the heads as possible. I also would rather not bore the case.

Go to 914 world member McMark, he has an awesome line of engines at a great price. I just got done with a similar build (2056) and didn't find out about him until I was to far down the road.

Ahhh Grasshopper, SEARCH is your friend

What you want to know is the head volume in cc. To figure that out, I believe you need the pistons and cylinders you want to use to get the deck height. Then figure out your static compression ratio from there with the head volume you have currently (including the piston dome), and figure out what it needs to get the compression ratio you want. I think there is some debate about the ideal deck height, maybe .030 -.040? Adrian should be able to help you, too - if you can get a hold of him.

I remember this process from my 2.0 Bus now, although the flat-top pistons made the calculations very easy. I'm thinking 8.5:1 will be my target as I will be using premium fuel (93 octane out here, 91 in California and elsewhere with some good octane booster to make up the difference).

Edit: But of course, if I can reach my ~92hp goal with lower compression I'm open to it. I'd like to keep it 1.7l so that I can re-use the rods and crank that I have.

Shouldn't be hard to find dome topped 90mm pistons. AA is what most people sell. Here they are, you can get them really cheap from the manufacturer:
http://aapistons.com/collections/piston-li...-top-piston-set

Having driven a 1.7L, 1.8L, 2L, and 2.056L 914, I'm not sure why you want to start with a small displacement engine. The 1.7L and 1.8L are turds. The 2L is almost enough HP to be fun. The 2056 is a bit more funner than the 2L.

You don't necessarily have to break the bank with a larger engine. I recently picked up a running 2056 with carbs for less than 1k.

As the saying goes: Theres no replacement for displacement

Factory 1.7L engines were at 8.2:1 with the standard 90mm domed pistons. Just removing the head gaskets(no flycut) will get you close to 8.5:1.

Some people like the way the shorter stroke early motors rev over the 2l.

That was where I tried first, but they are sold out. I've heard rumblings that they are discontinued. I found one vendor that listed them for sale and ordered a set; now it remains to be seen if they actually ship them out, or if they just forgot to update their inventory.

I want a 1.7 because the original 912 engine is a 1.6, and I want to keep the displacement and power delivery - as well as the overall output - as close to the 1.6 as possible. Since it's going on a cross-country trip, fuel economy does play a role as well.

Turd is a bit harsh....the 1.7 lasts longer and makes almost as much hp as the 2.0 liter

I haven't seen many folks pull that pesky /6 or 2L+ engine and install a fresh 1.7L...

As an owner of both, the 2.0 is a much better engine.

No case mods are needed with 96mm cylinders, they are a drop in replacement for all type 4 cases. The 1.7 heads will need to be opened up for the larger cylinder registers but if you are already having head work done just add that to the list. 1.8 heads will fit with no machining and may be a better starting point anyways.

I agree. I'm building a 1911cc engine now because it's exactly the same cost to rebuild as a 1.7 liter if you factor in head work. I like the 1911cc engine because you get much better power (rev happy) but still get excellent mileage.

Many don't care about the mileage since these are basically fun weekenders, but where I live it's meant to be a great cruiser so MPG is an important factor.

Also, I do miss soooo my 912. I bought it just out of college but couldn't afford the engine work when trouble happened. For me, it's always the one car that got away...

,the super 90 engine is getting old now and very expensive to overhaul,in fact way more than a T4 and that's not cheap....
If you aren't worried about keeping the car stock this is the conversion to do.
Jake Raby has done some great conversions on these older cars to good result,don't want to sound harsh but the OP needs to fully read the replies and research all options,there are extra costs to this conversion that need to be considered besides.

While you may not be concerned with higher horsepower, you will always appreciate increased torque. I agree with the recommendations to consider a 1911 conversion, 66 x 96.

You may want to visit the Shop Talk Forum, Type 4 Forum, and do a little reading.

http://www.shoptalkforums.com/viewforum.ph...1f5f5c924779aad

Well I'm not stubborn enough to ignore the advice of a dozen-plus people; however I may have a source for NOS 1.7 dome-top pistons. If that pans out, I will stay with a 1.7 since I place an almost unreasonable value on using German parts whenever possible.

If not, I'll go 1911.

As for the conversion, it is more than just "drop it in and go" but it also doesn't require any permanent modifications. Engine tin and a rear mount are the two biggies; I'll be ordering a DTM kit soon to help on that front.

I have a set of 912E tin for sale.

if you have two sets of head tin, and a fan from an old 36hp vw motor, you can make it look correct for a 912/356 install.

the alternator mount can be had at CSP in Germany.

Rich

Good idea on the CSP kit! I actually do have some sort of complete Type 1 laying around; it may well be a 36hp. It looks like with some creativity I can mount my breather and filter from the 616 and it will be very difficult to tell there's a Type 4 underneath.

My NOS 1.7 Dome-tops are on the way; I'm very excited about those even if it means losing some power or torque vs. a 1911.