My 968 engine build
 

Broke the head on my 87 S, so I finally built my 968 engine for the car… What a long, tedious assembly! Pretty much stock build, all new bearing and seals, crank scraper and head has a valve job and the pockets were opened up.
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nice porting job did you do it?? looks great.

No, local shop did the head work and honed the block. They specifically said it's not ported- these ports are massive as it is. They just "opened the pockets" up.

That's a massive engine. Let me know if you ever want to sell it!

Beautiful. Who did the machine work?

How was the block honed?

Hopefully not like this: http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/782248-my-16v-engine-build.html

It was honed properly. Abacas Racing in Virginia Beach did the work; they've done some 944 race engines in the past and were knowledgable. As for selling it- sorry. Need this for my daily driver after her engine broke. Plus I doubt I could get my money back out of it...

Did you time your own cams?

Yes. See the third picture...

Thanks, found your thread on the "other" site.

Haha, no worries!

Do you have a close up shot of the dial indicator assembly extension.

I bought it from Harbor Freight… It's a vice grip with a long, adjustable arm that the dial attaches to. I just clamped it to the block under the head and placed the dial where I needed it and locked the arm in place.

Here's a picture of my setup. I bolted a small steel plate to the block to support a magnetic base for each of the two indicators.

http://forums.pelicanparts.com/uploa...1386340423.jpg

obviously those are all shots speedy put up are BEFORE timing the cams, as the bolts that hold the exhaust cam are not in place.

there also needs to be a second mechanism for reading the relative position of the piston, as the timing marks are usually about 5-10 degrees off. i've never seen on yet that is bang on. it needs to be one such that you can rotate the engine a few times and see TDC as it comes around each time, and simultaneously read the lifter gauge.

lear's shot is correct

I found TDC myself before even putting the head on, checked and rechecked, and made my own reference marks for it.

well, i suppose that essentially does some of the same thing a degree wheel would do, except for not being able to set the cam at a specific degree of opening, which would be more accurate than the tappet measurement.

the only issue then would be any variance in the piston position, which occurs as you rotate the crank. even with a mark, as you "float" over TDC, the piston moves quite a bit, which you can clearly see with a gauge. it's almost impossible to mark the crank pulley or anything that small, and get it dead on. depending on the angle of viewing, it's very easy to be off a few degrees. that's why a large degree wheel is better. but, with a gauge, you know exactly where the piston is.

when doing my build, we had to use both to get it truly right. the differences due to the design made for some pretty large changes in cam locations. this could easily have made some large changes in power, had we not have gotten it right.

the engine will run almost anywhere, and i'm reasonably sure you will be able to drive just fine. it's all about how much power you want, and where.

And I understand that. I don't have a laboratory nor the precise instruments to make it prefect. If I'm so inclined and have the time, I may attempt to vary cam timing in the spring maybe, and see what kind of changes my G-Tech can show me.

yeah - it may not show up on the g-tech, but it will on the dyno.

as a note though, many shops don't time the cams. they just use the template and run with it, often just setting it in the middle of the slots. i guess they figure that it runs, and the owner will never know the difference. in most cases, they are probably right.

those of us who have been seeking every pony from the 968 do things a bit differently though.

timing
 

Speedy, not exactly sure how you checked your timing, but you seem to know what you are doing. I read that you had checked for TDC before putting the head on, which in my opinion is the most accurate way.
The way I have done it before is to have a degree wheel on the crank...a positive stop device bolted over #1 cylinder, rotate crank and mark on the degree wheel, reverse rotate and mark where it stops, divide by 2 and that should be TDC.
Having the stop directly over the center of the piston should eliminate most play.
I would think that belt elasticity and thermal expansion would have more effect than a small amount of piston rock, which if you can determine that amount, then it can be compensated for.

That's essentially what I did. Found where the piston just started to move on either side of TDC, and split the difference to mark TDC.

Got the engine in the car last night!
What's recommended break in oil and process?

I was just watching Ass Monkey Garage the other day and they ruined two completely different rebuilt motors by following improper engine break in protocol. Lesson learned from those 2 episodes; do not use break in additive, purchase expensive break in oil with as high a zinc content as you can find.

Fill with 20W50 and let it rip tater chip.

Any particular brand…? Non detergent or standard oil with zinc?

These aren't air-cooled airplane engines. You don't need straight mineral oil or anything like that. When I did my 968 rebuild break in earlier this year, I used standard multweight oil (I used Valvoline 10W-40 Premium) . I ran it an easy 500 miles. I drained the oil through a paint filter to see if anything was in the oil. I also cut open the oil filter to inspect the paper element. I expect you will see some tiny pieces of debris. This is normal.
Then refill with whatever oil you plan to run normally and as said earlier, let 'er rip.

Got it started yesterday afternoon! Time to finish bleeding the brakes, fix a little water leak, and get an alignment!

Congrats on the build! Keep us posted.

If you have questions on converting a 944S to a 968 driveline, let me know. Pretty sure I figured it all out; it's not rocket science!

Just an update- I played with my G-Tech Pro a little...
The last time I used it in this car with the original S engine, I got about 125hp.
New engine read 200hp... I put a new O2 sensor on the car after that too, since my gas mileage has not been what I expected, so I'll see if that made a difference soon.

The 968 motor gets significantly worse mileage than the S motor, I do 16/25 in my swapped s2. Your S will likely do worse since the gearing is a little shorter. My S gets 19/28.

I used to get 27ish on the highway with my S, but was down in the low 20s before the head went... I was looking for better out of the 968 between it's better engine management with the 944's lighter weight...

Nice work! Weight won't make much diff on highway mpgs. My 968 does 24.x mpg all the time (mixed driving). I've never done a full tank of lowish speed highway though. Speed limits here are 70 and traffic flows around 80...

And I've heard others claim 30 or close to it in there 968s...

it really depends on speed. at 55, you can get over 30 in a 968. at 65 you'll get about 27. at 75 it's down to 25.