Specific Question - ARP Head Studs on 2.7 Magnesium case - Insane?

[Lapkritis]

Originally Posted by Henry Schmidt

You seem to be basing your attack on this statement: Which clearly states I didn't use 90mm cast iron cylinders. Nowhere does it say I didn't test cast iron cylinders or use smaller cast iron cylinders to evaluate the possibilties.

I've shown the quotes I took issue with around cylinder temps and dates. I'm not here to argue with you and there is no attack. I covered this all before and digging up the hatchet is not wise. Not wise at all.

[304065]

Originally Posted by Henry Schmidt

If this is a question about the Rockwell tester and measuring scale,
we used a Rockwell 3R and measured on the B scale.

LOL no I was asking what manufacturer of rear main seal he used.
Only took me a SECOND engine drop to realize that Victor Reinz is junk. . .

[Lapkritis]

Originally Posted by 304065

LOL no I was asking what manufacturer of rear main seal he used.
Only took me a SECOND engine drop to realize that Victor Reinz is junk. . .

Elring Klinger in the red and white box purchased separately from the host here. I've purchased a lot of additional seals so I have about 80% of the original Victor Reinz kit boxed up new still even with the job done.

The old seal was bottomed out and appeared perhaps a roller bearing was visible directly beneath. It was so loose around the shaft that was what appeared to be visible anyway and I'm unfamiliar with the bearing layout inside the transmission. Normally would run a couple screws into the old until they bottom out and push the seal out but not with what appears to be a bearing visible for fear of damage. There's enough room to install maybe 4 additional seals on the shaft before you reach the splines. Simply bottomed the new seal against the old blown out seal. Sits square and provides better opportunity for oil splash through the gusher to keep it happy.

[Walt Fricke]

Neither bearing - ball, roller, or other - nor bushing of any sort reside where the input shaft comes out of the tranny into the bell housing. Closest bearing is on the other side of the ring gear where it leaves the diff area. Ring gear edge is pretty close.

Sounds like you have the intermediate style, which is what Porsche used the tool Henry pictured for. Compared with the earliest, it must have been heaven. And you could use screws. I hadn't thought of them pushing the seal out, but will bear that in mind. I've had using screws and a slide hammer in my reserve of techniques.

I had wondered if the input shaft had enough machined surface to do what you did and install new on top of old. Now I know. Always something to learn.

A bent input shaft (AKA mainshaft) can, I am told, make short work of that seal. Hope that wasn't the cause of the "see through it" gap around the seal lips.

[Lapkritis]

Hi Walt- thanks for the info. Must have been a reflection of the splines somehow inside the seal to the metal surface.

The records for the car (big thick folder) go back to around 1980 without indication of the output shaft seal being replaced. Mature drivers from what I know, zero track time. First guess would be aged/worn seal. If a leak develops soon after install of the new then output shaft would be inspected. I did rotate by hand and did not notice any twist or bend in the shaft.

Unable to locate the clutch lever circlip as the last piece of the puzzle so ordered from host next day air along with a few other bits thanks to their rewards coupon emails baiting me in. My brother got a look at the car yesterday for the first time. He has a lot of experience with MSD and HEI systems with a race team he crew chiefs for. May be adding in the soft touch limiter for the 6A setup currently in there. More updates this weekend I hope.

[Lapkritis]

Saw this today, thought it was funny for myself...

[Lapkritis]

1974 911 PMO 2.8L - YouTube



Edit for video link update.

[HawgRyder]

Well...it runs...LOL
Sounds like it's a little lumpy...but tuning should take care of it.
Good job.
Bob

[rsscotty]

Sounds like, listening to it crank, a new 1.5hp starter would do wonders for cranking. Along with a fully charged battery.

Just a thought.

[Lapkritis]

Thanks Bob. Didn't think it would start up and was about to quit and glance things over again.

Original starter... cranked the same prior to the top end job. The starter looks rough and is lazy. All connections are clean and tight.

Slow drip from the oil pressure sensor/right cam feed line where it goes into the case. After that's addressed only license plates and break-in drive remain.

[HawgRyder]

Andrew...the starter on your car really does sound slow.
Mine used to crank a lot faster...but it was a 2.0 so maybe that had something to do with it.
An old trick for very hard to start VWs at the time was to put a 6V starter in and feed it with 12V.
You had to change the nose bearing in the case...but other than that it was an easy fix...and wow...did they ever spin over!
I wonder if there is a 6V starter (from 356s?) that would do the same thing?
Bob

[Lapkritis]

I see there are 2hp on EBay... I'm going to resist until this one doesn't get the job done. Starts much easier with the carbs full of fuel now.

Going back a few steps now that a hectic week has passed. Here's how the rockers went in.

Clean up all the holes with WD40 and a clean papertowel.



Parts for each rocker... new everything except shaft and adding in the seals that weren't there previously.




Clean the crud out of the ends with a scotchbrite pad and some brake parts cleaner:



Goal is spotless, clean taper and no debris... you will be surprised at the junk trapped in some of these:



Light lube/oil of the hardware to prevent galling during installation:


Installing the seals and being careful they don't flip inside out...

[Lapkritis]

I chose to lube the o-rings very slightly to encourage proper seal. I took special care to not drive a lubed o-ring through the rocker arm as that would likely cause lubrication issues blocking oil. I did this by applying a small dab of o-ring grease (same as used on the case through-bolt seals) to the far side housing and to the trailing seal on the rocker.









Torqued to 18ft lbs and a couple took a bit more. Final torque method was no resistance on the non-torque end tool to show the shaft secured in the housing. Care was taken to ensure the shaft seal was centered in the thin cast of the housing for each and the bolts were removable from within the housing so they may be serviced with the engine in the vehicle and all tins attached.

[Lapkritis]

Oh, and oiled the rockers a couple of times after all tightened up. Couple drops of oil, wiggle it around and return a few hours later and repeat.



Seemed to be intended for the job:

[Lapkritis]

Need to locate the unisyn that came with the car. Infrared shows cyl 1 and 5 cooler than the rest. Spritz of carb clean on those smoothed out the idle and raised rpm. Full carb tuning session coming...

[Lapkritis]

Haven't been able to head to the storage area where the unisyn is located so tried an alternative method.

Set idle to 2k rpm with hand throttle.

Spritz of carb clean into each throttle body, one at a time and note reaction of engine speed.

Cyls that bog when carb clean introduced received no adjustment at this time although the reaction on those was uniform.

Cyls that raced or increased engine speed received adjustments of 1/8 turn out in idle mixture (more fuel) until spritz yielded same bog as other cyls.

Exhaust note now smooth, throttle response crisp. Egt for all 6 cyl is +/-20°F. Would still like to confirm balance is precise with unisyn for all cylinders.

Preliminary Idle test shown head stud 8% warmer than cylinder. More measurements once this starts being driven. I will share spreadsheet of data collected for the various components at the same time.

[Lapkritis]

Unisyn found, one cyl was off a tiny bit. Will probably service carbs with kit from the host to be safe.

1st drive/ring break-in tonight and had my brother along for an extra set of ears just in case. Did the wot/engine brake cycle quite a few times. Engine feels great. Zero detonation. Zilch. Nada. Distributor was returned to exact previous position because it was marked during teardown. Power is up from previous configuration with the RS 2.7 according to my seat of pants. More curve above 5k rpm. Changes were webcam regrind of similar profile, 92mm bore (+2mm), compression to 9.5:1 (+1pt).

Returned to garage after 30mins of ripping and idled down. Sink tip 167°F, vc at base of sink 211°F, engine case 188°F. Not sure how but cyl temp at middle was 190°F, head fin 190°F.

Oil change and will report back with more data collection.





Before pic to see where we came from:

[tscrihfield]

Nice build!

My personal take on the iron cylinders. They'll be fine. I have a good friend running a twin plug 2.5 long stroke small bore engine that dyno'd at 265hp @ 6xxx rpm. I've watched it run three maybe four seasons without rebuild and he runs 10-12 weekends a year.

I bought a 74 2.7 and plan to build it in the next year or so... Keep us up to date how the cylinders hold up. I may have missed it mentioned, but what pistons are you running?

Thomas

[Lapkritis]

Thanks for the comment Thomas; the silence in here since making the most recent progress has been deafening.

Your friend's engine sounds like quite the healthy 2.5 with that power output and the type of use; I would like to get to the dyno once the break in is complete and the carbs are sorted with confirmed steady air to fuel ratios. Just looking for average, healthy power output as you would expect from a 2.7 with these mods.

Pistons are the JE 9.5:1 92mm off the shelf pistons. Had to hone the cylinders out to gain proper clearance to fit. Hindsight I would custom order the JE pistons a bit smaller to limit the time on the machine for the cylinder work. These take the engine to a smidge over a 2.8L. Time will now tell how they wear and perform; will be run with synthetic oil and a close eye on fueling. If fueling is out too far even with a carb rebuild and tune then going to go efi. I'd really like for the carbs to work out on this though to preserve some of the raw character that attracted me to the car in the first place.

[rsscotty]

Listed on Ebay 1.8 hp OEM starter or buy a new one for around 245.00.

The slow spinning starters are .8hp.

Porsche 911 Starter Bosch SR 68 x Original Starter | eBay