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-   -   Different type of engine build project (http://forums.pelicanparts.com/porsche-914-914-6-technical-forum/373788-different-type-engine-build-project.html)

sasquatch 10-24-2007 07:12 AM

Different type of engine build project
 
I have been wanting to build some sort of monster motor (i.e. Jake) for my 914 for some time. But sadly, the funds $$ are simply not there. In reality, very little funds are available for this project at all.

This leads me into this post. I am looking for opinions from the collective on this. I am going to list out what I have and what parts I have in house and I would like your collective opinions on what I should do. I understand I am not going to get a monster motor, but I would like some additional ponies under the hood.

The car: 1974 1.8. 104k miles. Showroom, unrestored condition. No rust ever. Runs perfect. And by perfect I mean as new perfect. Original motor, only been removed once by original owner to install a lightweight clutch. Starts, drives, runs like clockwork. Heck, the thing does not burn or leak any oil at all.

Parts on hand: Besides the excellent running 1.8 in the car, I have a complete 1975 2.0 long block, in pieces, in the garage. The engine ran decent, but was tired. Burned and leaked oil, but ran fairly strong. (I personally drove the car) So all the parts are useable with reconditioning. I am unsure of the condition of the heads. They do have the air injection ports which I do not like.

Goal: Build as decent a motor as I can with as little $$ invested as possible. I do my own work, have a very stocked garage with most of the VW specific tools required on hand. I have built many type I motors and a couple of stock type IV motors in the past, so skill and ability is there. The only work I will outsource is machine work.

So, looking at what I have, tell me, in your opinions, what I should build. I can always build a monster down the road as money permits.

Tobra 10-24-2007 07:26 AM

Budget as much as you can for heads, then add 25-50% to it, heads and cam have to go together

hank911 10-24-2007 06:27 PM

Engine Build
 
Hi Jay,

I'm in about the same boat. Low budget but I have two core 1.7's and a 71mm crank & rod set along with three 2.0 heads. Luckily the heads are crack free but two of them have had "big" valves installed.
I'm thinking of sending the heads to Len Hoffman and going with some 96mm's and a cam & carbs for a nice little short stroke. The other option with my budget would be to go with the 71mm crank and do a 2056.
I'm still waiting to hear about the 1911 vs 2056 to make my choice.
Are you staying with the FI or going with carbs? I'm guessing a new FI or MegaSquirt is out because of the budget.
Take a look at some of the past threads, I thought I was sure I wanted a 2056 but after reading some posts on a short stroke(66mm x 96) I think it would be a great compromise that'll work on my limited budget also.
Then again, maybe a rich uncle will leave me a pile of money and I can get that street dominating "Jake" motor after all!

Good Luck!

sasquatch 10-24-2007 07:01 PM

Quote:

Originally Posted by hank911 (Post 3550841)
Hi Jay,

I'm in about the same boat. Low budget but I have two core 1.7's and a 71mm crank & rod set along with three 2.0 heads. Luckily the heads are crack free but two of them have had "big" valves installed.
I'm thinking of sending the heads to Len Hoffman and going with some 96mm's and a cam & carbs for a nice little short stroke. The other option with my budget would be to go with the 71mm crank and do a 2056.
I'm still waiting to hear about the 1911 vs 2056 to make my choice.
Are you staying with the FI or going with carbs? I'm guessing a new FI or MegaSquirt is out because of the budget.
Take a look at some of the past threads, I thought I was sure I wanted a 2056 but after reading some posts on a short stroke(66mm x 96) I think it would be a great compromise that'll work on my limited budget also.
Then again, maybe a rich uncle will leave me a pile of money and I can get that street dominating "Jake" motor after all!

Good Luck!

I am going to stay with the stock FI. After years of tweaking jetting, I refuse to do it any more. FI is the only way to go. The L Jet on my 1.8 works flawless. Hot or cold, from sea level to over 10k feet, it just works.

I will go look for some your threads and re read them closer. I also need a quick education on what the bore and stroke is for the 1.8 and 2.0 motors. Is there an online chart somewhere that I can look at what displacements are created with different bore and strokes?

Dave at Pelican Parts 10-24-2007 07:31 PM

Dig out your calculator...

Displacement == (bore/2)*(bore/2) * 3.1415926 * stroke * #_of_cyls

In our case, the number of cylinders and the half-the-bore bits cancel, giving you:

bore * bore * 3.1415926 * stroke

Not too hard...

That said:

96x66 = 1911cc
94x71 = 1971cc
96x71 = 2056cc

You can go bigger, but I'm not sure how well that would work with the L-jet EFI.

Supposedly the L-jet will work fine with the 1971cc (stock 2.0 displacement). I would worry, at least a bit, that it might lean out near red-line at WOT. A good dyno with a wide-band O2 setup, or your own WBO2, would probably be a good investment... The 2056 likewise might work, but you would need to make sure by testing it.

The 2.0 heads are going to be cracked--almost certainly. Have them fixed up by someone who knows what they're doing (Adrian at Headflow Masters for a stock build, or Len Hoffman at HAM) and stick with stock valve sizes and ports and such. Unless you're building a monster, the stock valves and ports are quite good, and you will be limited by the L-jet unless you get creative. The heads will probably be the costliest part.

A mild cam, like the Web 73 or Raby's 9550, should be able to be made to work with the L-jet. You will probably be doing some tinkering to get it working well, though.

Going to the "Euro" compression spec, or even a half-point more, could give you more zip. Note that you'll most likely want to use mid-grade fuel for the 8.0:1, or premium for the 8.5:1, so figure that into your cost calculations.

Throw the 75 exhaust as far away as you can, it's really quite awful. Use the 74 exhaust, or if you can fit it into the budget and want to lose all semblance of heat, look into a real tuned header setup. Exhaust seems to be critical to getting good power out of these motors.

What else? You can clean up the surface inside the case so the oil and air move around more easily. Clean up the casting flash on the heads so they cool effectively. There are probably dozens of other tricks that someone with time and tools but no money can do to squeeze a little more efficiency out of the motor...

--DD

sasquatch 10-25-2007 05:40 AM

Dave,

This is precisely the reply I needed. Thank you very much. I will probably go with the higher compression for a few more ponies. The car only gets driven about 1,200 miles each year, so fuel prices are irrelevant.

I do have more time, tools and ability than money. So I will be doing exactly what you suggest and spending time with each and every part polishing, blueprinting, etc. I did that once with a sport bike motor and picked up 7 hp just by blueprinting all the stock components.

Exhaust. Heat is critical. I will use the exhaust I currently have. I have the stock heat exchangers running into an ebay special header/glasspack. Most certainty not the best setup, but better than stock and sounds great. Would love a Tangerine setup, but very cost prohibitive at this point.

I will do a dyno run before and after the build to see what HP numbers I end up with.

Can anyone ad their input to the projected HP numbers and power characteristics of the packages that Dave suggested?

96x66 = 1911cc
94x71 = 1971cc
96x71 = 2056cc

Thanks again for your responses guys.

Tobra 10-25-2007 06:04 AM

I would bet that Jake Raby could tell you what you could get away with on an Ljet, or cruise some VW boards for info. It is air flow metered, so there is some flexibility in the system.

NOTASIX 10-29-2007 03:16 AM

Ljet is a serious limitation for these engines, just like D jet. With either of the two systems I have found the maximum SAFE engine output to be 110 HP. Abover this output the system cannot adequately manage fuel delivery and lean conditions around peak torque and above are hard to overcome, if not impossible.

I worked for years to make more powerful engines equipped with stock FI and was not successful at all, even with different exploratory approaches.

sasquatch 10-29-2007 05:41 AM

Quote:

Originally Posted by NOTASIX (Post 3557863)
Ljet is a serious limitation for these engines, just like D jet. With either of the two systems I have found the maximum SAFE engine output to be 110 HP. Abover this output the system cannot adequately manage fuel delivery and lean conditions around peak torque and above are hard to overcome, if not impossible.

I worked for years to make more powerful engines equipped with stock FI and was not successful at all, even with different exploratory approaches.

I know better than doubt your experience Jake. With the budget I have, or more correctly, dont have, 110 HP seems like a reasonable expectation right now. Just buying a carburetor kit is probably $1000. I hope to build the entire motor for less than that.

I do have a complete D-jet system I ought to try and sell and maybe that will help offset the price a bit.

But again, I am a HUGE fan of injection and will try and stay with it for as long as I can.


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