1970 911T motor shot. Where to go from here?

[darmahman]

Long story short - Bought 1970 911T last month. Had a weird rattle/knocking noise above 3500 rpms. Took it to a shop after buying the car (didn't do a PPI as PO assured us it was solid...).Engine had been rebuilt in the 80's. (10,000 miles ago. Car sat a lot after rebuild. ) This shop is a VW / Porsche shop in my area. The owner thought it was a rocker arm...
I decided to then send it to a shop in Denver that has a much more experienced engine man (Jim @ Eisenbuds). He drove it and said the motor was gonna blow any time.(My son and I had only put less than 200 miles on it since buying it, all below 3000 - 3500 RPMs as that is when the noise begins(under load).

We decided to have Jim tear it down. So... the motor is shot. Rod bearing spun. Crank is shot. Already one under. So at least we need a new (to us) crank and rods, pistons, cyl. bored 10 over, blah blah blah. $20K or so...
Would like to see more power but make reliable. Thinking 2.4 crank and E cam with more open exhaust(needs total exhaust anyway as it is original). Car is equipped with Webers already.

Would love to here from the knowledgeable what direction they would go. Money is an issue as always but not afraid to spend 10-20% more if it would make a dent in the power/ reliability area. Eisenbuds has been great to work with. Just looking for other/more ideas.
Thanks in advance. Great forum BTW. Mike

[Henry Schmidt]

Here is the engine I built for my 70T about 6 years ago. Fun to drive, great acceleration and smooth power.

Twin plugging is of course an unnecessary option.
This was from the add I used to sell the car.

The engine is a 2.45 liter twin plug with DC Mod “S” cam and 9.5:1 compression.
The entire engine was balance to 1gram.
The case has CaseSavers, oil by-pass mod, 3.2 Carrera pump, line bore and oil squirters.
The 2.4 (70.4 mm) crank was magged, polished and cross drilled.
The pistons are CP 9.5:1 forged racing pistons in new 86mm Biral barrels.
The rods were rebuilt ARP bolts & Supertec nuts.
The heads are 2.7 liter with 36mm intake ports and machined for twin plugs.
Phosphorus /bronze valve guides and new oversized valves (47, 41) were installed.
The valve springs are Supertec 240. The head studs are of course Supertec.
The cams are 4 journal billets, DC Mod “S” for great mid range to high RPM performance. 10,000 RPM tack.
Carrera chain tensioners, chains, ramps with Supertec tensioner arms were installed.
Rockers are rebuilt with Teflon lined bushing and Rockwell tested to guarantee cam compatibility. Shafts were polished.
The carburetors are 40mm Webers completely re-manufactured. PMO manifolds.
A Supertec Power Pulley was installed with new belt and remanufactured alternator.
The distributor is a Rennwerks Gen II triggering an MSD 6AL CD box.
The exhaust is SSI with sport muffler.
Dynoed at 180 RWHP @ 6400

[Black 993]

$20K seems a bit steep for what's involved here. I rebuilt my '70T a few years ago with the works and can cite some numbers. Good used crank/rods, either stock or 2.4, can be had for well under $1k. You'll need about $2K in case machine work (I used Ollie's). I did piston squirters, oil bypass mod, etc. I sourced a good 4-rib oil pump for $400. You can get good used or reconditioned p/c's for $1,500. Assuming you don't have to buy valves the heads will be $1K+ for new guides. Being T heads you might want to open up the ports but this is pretty cheap and simple. Overall you shouldn't be into for more than $8-$10K in parts, and it doesn't take $10K in labor to build an early motor.

[targa72e]

Henrys build is pretty nice formula. I Have had two engines in my 914-6 conversion in the last year. One was a 2.4 E MFI and the other a 2.7 with RS pistons and Mod S cams with Webers. The mod S cams and 2.7 rock, 2.4 and E cams are OK. Open up the ports, add displacement, add compression (you can get away with a little more at altitude) and add cams. There is always talk about how peaky the S engines and big ports are and that the T engines have tons of low end torque. That is just not the case. S engine might feel peaks (butt dyno) but that's just because it has so much more on the top end compared to a T. This link has a thread I posted with factory HP and Torque graphs for T, E, and S. you can see that they are very similar under 4000RPM but much different above.

The exageration about peaky S engines.

john

[Cairo94507]

I would suggest contacting Bruce Abbott, Flat6pak on this forum. He has been building Porsche motors for over 40 years and he did the 3.2 in my car and it runs great. He builds them in his garage and documents it all with pictures. The bright side is when you get your motor back you will know it is fresh and no future worries. Good luck.