16v refresh/"while you're in there"

[Fraser_Crenshaw]

I've been wanting a 16v motor for my 85.5 NA for some time now and recently found a pretty good deal on one. It has roughly 150k on it, came with accessories, harness, dme, intake components, clutch, etc... I actually have yet to unwrap it from the pallet and see exactly what I have or need since the weather fully crapped out today.

While I'd prefer to avoid completely rebuilding the thing, I do want to give it a good refresh while I have time to work on it out of the car.
Here's what I'm thinking initially:

Timing belt/components
Cam chain pads
All seals
Clutch
Basic tuneup stuff- plugs, cap, rotor, if necessary.
I was recommended to do rod bearings, is this overkill?

Any reason to do the cam tensioner itself? Seems like most just change the pads.
Any hop up stuff? I would consider aftermarket cams at the risk of scope creep, probably end up doing a HG at the same time. I'm guilty of going unnecessarily overboard with stuff like this...I mostly would like to just make it as reliable as possible before it goes in the car.

Also, I think I have most of the parts necessary to swap into a standard NA car, but I'm a little curious about the bell housing. I think I read that the S cars had a different reference sensor bracket or something? I hope I don't need an S bellhousing...

Here's a photo of car for attention. Thanks for any advice you may have to offer!

[djnolan]

Maybe do the intake related stuff such as ICV and AOS lines. Also clean the ICV and AOS. Definately do the oil cooler seals. Also easy to do some power steering line replacements while the engine is out (lines, pump seals). Definately replace cooling system hoses, too.

[944 Ecology]

The 16 valve engines use a different flywheel and a single flywheel sensor (unlike the 8 valve engines, which use two flywheel sensors.)

You can use the forward hold on your 8 valve sensor bracket and it will work fine.

[v2rocket_aka944]

I have a 16v-specific adjustable cam gear for sale that will allow you to dial in the power band (advancing should make a great difference)...if interested.

[Pauld_94S2]

Yes, 944 S2 is a great Porsche!

Timing belt/components = Yes
Cam chain pads = Yes
All seals = Yes, include rear main
Clutch = optional but why not?
Basic tuneup stuff- plugs, cap, rotor = yes
I was recommended to do rod bearings = yes, since it's easy to get to now
Motor mounts = yes

OK, now for the bad:
You won't like the acceleration unless you replace the trans, do some research
Air filter is going to wrench your plans since it lives inside the fascia & sheet metal in the nose.
Also, all front sheet metal, fenders, fascia, front panel, and headlight covers are different if you want it to look like the picture you posted.

My advice? Find an S2 that has a broken/missing engine but with trans and go from there.

BTW, the S2 is highly advanced over the base 944, suspension and brakes are different and very costly ($$$$) to change out. That's if you are trying to build an S2.

Start studying the factory service manuals to get an understanding of the differences between the base model and the S2 so you have a more complete knowledge of the issues.

[djnolan]

There are major differences in the intake and HP/displacement depending on if it is an S or S2 engine. The S airbox is in the engine compartment, the S2 is in the nose panel although it could be relocated with a cone filter.

You could add a MAF kit to the current 8V engine and get halfway to an S engine. Since the chassis was originally designed for the 8V motor you could make do with the current brakes and suspension.

[v2rocket_aka944]

Originally Posted by djnolan

You could add a MAF kit to the current 8V engine and get halfway to an S engine. Since the chassis was originally designed for the 8V motor you could make do with the current brakes and suspension.

As the world's foremost proponent of ****-canning the AFM for a MAF or MAP conversion I'm gonna have to shoot this one down.

A MAF conversion opens up a whole new world of performance and responsiveness but by itself will only get you ~5 peak HP. Under the curve is transformed wholly but the dyno number you'd brag about is only bumped up a little bit. That said, everyone with an NA should DEFINITELY get it, you will love it.

See below for stock DME/AFM vs NA-tune MAF kit.

[Fraser_Crenshaw]

Originally Posted by v2rocket_aka944

I have a 16v-specific adjustable cam gear for sale that will allow you to dial in the power band (advancing should make a great difference)...if interested.

Details? How much? Feel free to PM me. I ran the cam advanced on my 8v for a while and hated it- power just fell off horribly in the higher RPMS.

[Fraser_Crenshaw]

Originally Posted by Pauld_94S2

Yes, 944 S2 is a great Porsche!

OK, now for the bad:
You won't like the acceleration unless you replace the trans, do some research
Air filter is going to wrench your plans since it lives inside the fascia & sheet metal in the nose.
Also, all front sheet metal, fenders, fascia, front panel, and headlight covers are different if you want it to look like the picture you posted.

My advice? Find an S2 that has a broken/missing engine but with trans and go from there.

BTW, the S2 is highly advanced over the base 944, suspension and brakes are different and very costly ($$$$) to change out. That's if you are trying to build an S2.

Start studying the factory service manuals to get an understanding of the differences between the base model and the S2 so you have a more complete knowledge of the issues.

Sorry for the confusion. I bought a standard 2.5 "S" 16v motor. I would love an S2 engine but budget just didn't allow it right now. I think I'll be happy with a slightly tweaked 2.5. My biggest gripe was the lack of top end with the 8v, especially on the track, just never feels willing to rev...

I've heard the 16v motor w/8v trans combo is actually pretty decent since the "s" cars came with fairly tall gearing, I could be wrong.

The car in the photo is mine- a previous owner swapped the front end with turbo/S2 stuff already. It's a pretty capable track/autox rat already, hawk pads and good fluid with the stock brakes are pretty darn good. I'll consider upgrading to turbo/S2 down the road but currently not a priority.

Thanks for your advice!

[Fraser_Crenshaw]

Originally Posted by v2rocket_aka944

As the world's foremost proponent of ****-canning the AFM for a MAF or MAP conversion I'm gonna have to shoot this one down.

A MAF conversion opens up a whole new world of performance and responsiveness but by itself will only get you ~5 peak HP. Under the curve is transformed wholly but the dyno number you'd brag about is only bumped up a little bit. That said, everyone with an NA should DEFINITELY get it, you will love it.

See below for stock DME/AFM vs NA-tune MAF kit.

Love this. I have a turbo e30 running on Megasquirt and it rips. I saw there actually is a MSPNP available for the 16v motors- this is already on my radar as I would love to ditch the AFM and open up a bunch of MAP based tuning possibilities. Is there an affordable MAF conversion setup out there? I feel like the investment would be better aimed towards a standalone setup...

[v2rocket_aka944]

Originally Posted by Fraser_Crenshaw

Details? How much? Feel free to PM me. I ran the cam advanced on my 8v for a while and hated it- power just fell off horribly in the higher RPMS.

$250 shipped OBO.
PM me with an email address for pics.

I think you may have had your gear retarded rather than advanced.

After putting the MAF onto my 944 I advanced the cam and it made more power at all RPMs than stock "straight up" cam timing.

I liked it so much I contemplated going a full cam gear tooth (9 degrees) to get all the sauce but changed plans on the car shortly after that.

[guru944]

v2rocket_aka944;

Is your posted dyno of a 8v or 16V 2,5 or 3.0 engine?

I would not recommend Advancing past +/-4 degrees of Cam Gear since our V8 and V16 are Interference engines (Potential damage would be catastrophic) like bent valves, damaged Head, Pistons, Rings etc.
I would highly recommend Stage 2 ported Headwork and tapered SS Valve over any camshaft mods anyday (more street-able and torque).
More CFM means capable of more HP and Tq.
Later,

[v2rocket_aka944]

Guru - that's an early 8 valve 2.5

Yes they are interference but the "pistons chase the valves" so even 1 full cam tooth advanced (9 degrees) you wouldn't have the valve touching piston around TDC.

If the belt breaks you're going to have bent valves no matter the cam timing.

And I would strongly recommend putting a hotter cam on the car before ever unbolting the head. The SOHC 944 cam is so tiny that anything would be an improvement, and the 8v heads already flow "ok" that it's not a real limiter at that point.

But this is getting further OT for the 16v thread.

OP - you DO want to get a MAF or MAP conversion (aftermarket ECU) because the AFM sucks, the stock DME is 1000 years old, and they conspire to rob you of power that would otherwise be there if the engine could just breathe.

...make it better with my cam gear... PM me.

[walfreyydo]

Originally Posted by v2rocket_aka944

As the world's foremost proponent of ****-canning the AFM for a MAF or MAP conversion I'm gonna have to shoot this one down.

A MAF conversion opens up a whole new world of performance and responsiveness but by itself will only get you ~5 peak HP. Under the curve is transformed wholly but the dyno number you'd brag about is only bumped up a little bit. That said, everyone with an NA should DEFINITELY get it, you will love it.

See below for stock DME/AFM vs NA-tune MAF kit.

I am not aware of any MAF conversions for the S2, anyone know of any? Closest Ive found is the Vitesse ECU standalone ($$$).

[v2rocket_aka944]

VEMS plug and play, about $1300 bones

[Fraser_Crenshaw]

FWIW diyautotune makes a MSPNP2 for $799 that will work with S and S2. Having used that same ecu on my turbo e30 for a couple years I can say it's a pretty killer value. Not a MAF conversion per se, it uses an onboard MAP sensor.

[azbanks]

The VEMS system is really nice because it is plug and play. Plugs into the existing wiring harness and Peep(raceboy) will help with any questions or issues.

[Fraser_Crenshaw]

Ok, a little update since this evolved somewhat from what it started out as. The "while you're in there" took on a life of it's own (as usual) when I decided that not replacing the headgasket while I was already this far in would be a silly move. So off came the head.



The piston tops looked pretty gross, not terrible, but not good. At this point since I was already planning on replacing the rod bearings, I figured I'd pull the pistons, which exposed the fact that the rings were pretty much all stuck.



I think this motor may have sat in the elements for a while since being pulled. It was in pretty good shape overall but there were problem areas that had started to develop some surface corrosion or worse. Pistons are still soaking in ATF, I'll replace the rings next week.

Disassembled the head to get it cleaned up:





In the mean time the head went off to our local amazing machine shop where it was cleaned, milled, valve seats were cut and the valves cleaned and cut. Just got it back this morning and it looks phenomenal.

[PHillary]

See Web Cam Racing cams really changed how I felt about the car...really satisfied for the money spent

[Fraser_Crenshaw]

Man, I looked into getting some hot cams to toss in there while it was all apart but holy smokes are they expensive! That particular upgrade would sort of blow the budget for this project out of the water. Maybe down the road...