Which 914 engine best to build?
 

Me and a buddy are looking to build a mildly upgraded engine in his garage for his 914. It has a running 1.8 in it now but he would like some more power. Any suggestions on what the best engine to start with would be, 1.7 1.8 or 2.0?
Here is the car and the owner.
http://forums.pelicanparts.com/uploa...1346027613.jpg

There is no "best". There are things that are better or worse depending on your point of view, budget, priorities, and so forth, but there is no single "best".

Lots of decisions to make about things that will influence this. What kind of fuel system does the car have, the stock L-jetronic fuel injection, carbs, aftermarket injection? Does the owner want to tinker with carbs, fiddle the mixture on a laptop, use archaic analog electronics, or something else?

What's the budget? What sort of power levels are the minimum to be acceptable? Is it allowed to have poor street matters in exchange for crazy top-end power? Does it need any heat at all, for example to do-fog the windshield?

If your friend wants to throw five digits' worth of money at a motor, a 200+ HP/180+ lb-ft 2270cc motor can be built. See Welcome to Raby's Aircooled Technology Web Site for someone who will build that.

On the other hand, if your friend wants some form of bone-stock 914 motor only, the 2.0 had the largest displacement (1991cc) and highest power (95 HP) of the stock motors. The case is the same, but almost all of the important bits (crank, rods, pistons, cylinders, heads, valves) are different.

If your friend wants to use as much of his 1.8 as reasonable, the cylinders can be honed out to 96mm, making a 1911cc motor. With higher compression (something like 8:1 or 8.5:1) it can make decent power, and still use the L-jet EFI.

If your friend likes carbs, the 1911 with a very aggressive cam grind can make good top-end power, as long as the heads can be worked to support the flow and stay together.

For least effort and lowest cost, a stock rebuild would be best. A little more compression (as above) could make the 1.8 more responsive.


Lots and lots of options. No single "best" one, though.

--DD

A good rule of thumb is when HP goes up, reliability goes down and cost goes up, usually not proportionally! A 2L with carbs, slightly hotter cam, polished heads, headers and slightly higher compression will bump up the power to 120 or so and be good for a long time.

you need to think about all these things, induction, exhaust, etc... For a mild boost, a bigger bore cylinder kit can be added, but here are limits on what the stock FI can handle. I run a 2 liter D-jet with bigger 96 mm piston, had to tweek the MPS (manifold pressure sendor) But tweeking needs to be done on even a stock D-jet running todays new fuels. some compression increase can give more power, you will likely havve to go to high test gasoline vs. regular if you do that. more power means more heat eventually you will want to add an extra oil cooler.

Jake Raby has a bad reputation for customer service, I wont buy from him, burned me once. also burned a freind of mine. He is over priced to boot. Elgin Cams makes several nice FI compatible Cams that will increase power, they also have more radical cams for carbs. Check them out they know there stuff.

http://www.elgincams.com/c-por3.html

the above is Elgins 914 page of the online catalog.

give them a call, they are very very helpful on the phone, unlike Raby, who will charge you for advice.

Quality pistons can be found, J and E pistons are good, but can be pricey, cheaper chinese ones from AA can work, but one of my engien build freinds says that they have to carefully inspect the AA pistons, rejecting some. If correctly inspected, these pistons can work for less money, but make sure the builder measures them carefully, returning out of tolerance ones(AA has been good at returns, and quality has been improving)

also keep in mind the potential collector value of the 914, if you can up the power without cutting up the car (ie V8 conversion) you are likely to retain the value more.

also beware of curent or future smog testing laws. Some conversions are not smog legal.

The 1.8's L-jetronic EFI doesn't have a manifold pressure sensor... ;)

We know your problems with Raby, and I wasn't suggesting that he OP's friend necessarily go there. However, his $10K+++ engines do serve to illustrate one end of what can be done with the motor.

--DD

Thanks a bunch fellas. Already a lot of great info here to work from. To answer some important questions:

The 1.8 in the car has webers on it and he is not opposed to staying with them and away from converting back to old tech injection.
120 hp plus is the goal and doing it on a pretty strict budget.
The car has heat now and he would like to keep it that way.
The car is used for spirited driving in the hills and the occasional HPDE day. I would say torque over top end would be desirable.

So we are really looking for the biggest bang for your buck, that most of the work can be done in the garage. We are thinking of buying a tired engine (2.0?), tearing it down and rebuilding it with the goal of being over 120hp. Neither of us are mechanics but both have done a fare share of dyi and mid level restoration work in our garages.

It sounds like the 2.0 would be a first choice. We could pull the 1.8 and use it. What are the advantages / disadvantages of the 1.8 vs the 2.0?

The 2.0 heads are significantly better. Larger valves, larger ports of better design, and a re-located spark plug all contribute to the ability to make power.

The 2.0 obviously has more displacement, which certainly helps.

The 2.0 heads are notoriously fragile, often requiring a lot of work to use again. They crack across the spark-plug holes, and they crack in the short-radius bend in the exhaust port.

120 HP can be had reasonably easily by starting with a 2.0 engine, keeping the 71mm crank (and the rods that go with it), taking the 94mm cylinders out to 96mm to make a 2056cc engine. A good cam, some compression, and a little work to the heads should get you into that range.

--DD

Super, thanks Dave.
Any suggestions who could handle the head work here in the SF Bay Area?

Most of the top head work including welding, repairs and heat treatment is done in the L.A. area and the shop I used to do my race engines always mentioned a place named "Tuttles". Not sure if that is their name or a nick name so you could call Jeff at Black Forest in San Diego at 858-292-1192 and see what he can tell you. They did the $10,000 heads on my 2.8L stroker 4 years ago and it made over 220 ftlbs of torque at the erar wheels. Heads can be brought back from the grave if they have a lot of work in them such as port reshaping big valves and such.

Ted at Precision Machining. I think they're in Campbell, but it could be San Jose? Only been there twice--once to drop off the wife's 911's flywheel, and once to pick it up. You'll have to keep pestering him, as things can take a long time.

Elgin (the shop may not be called that but they're associated with Elgin Cams) in Redwood City is good for the milder-type stuff; they'd probably be good for what you're looking for. Talk to Rich Bontempi at High Performance House; he has forgotten more about 914s than most of us know.

Avoid Ellsworth in Mountain View. PM if you want the details of my experience.

Head Flow Masters is down in So Cal somewhere, and they are reputed to be good.

--DD

Ted at Percision Machining did well on machining my 356 link and king pin set up. He is busy but he does nice work.

I dont think Elgins has a store anymore in Redwood City, they moved top Santa Rosa, although you can still see there old sign on the building behind the City Pub. Elgins is first rate in cam shafts and is very helpful.

Rich at High Performance house is a very good source (650) 364-6234. and is fully capable of doing a stock or powerful motor (he sometimes has good used engines come in for sale, if you want to go used)

Also Jansen Enterprises in Belmont on Habor Blvd is an excellent air cooled engine shop. Ken jansen can do the heads, he has done several for me and friends, he can build the whole engine for you, or just head work, he has them welded as needed. He is a top rate race winning engine builder, I am very happy with the 2056cc he built for me. He has done three different engines for me, and is very reasonable in price, but you need to get in early has he is aways busy, he also is a great guy for advice, knows his engine stuff. He even supplies other engine builders with machinng. Real quality here.

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