cold_beer839

So '93 GTS numbers would be: 85P00501-00680

What would the top numbers be?

ROG100

Your car should have M28/49 if it says M28/50 then you just hit the jackpot and its an Auto 8>)

pcar928fan

^^^^^^
LOL! Love it Rog!

Vilhuer

If engine was changed under warranty new one has very likely M28/50.

Since car is '93 MY and not early '93 MY, second row should be 85P00xxx. What last three digits are is interesting. Since both ROW and US model shared same engine number its likely they also shares one single internal engine numbering. This means both market 5sp models must be counted together when estimating what engine serial number can be.

Since this is 36th '93 US out of 102 made its about 1/3 in production run. Fact that 19 early '94 MY US GTS were made in spring '93 and very likely share same engine number series complicates things a little but 19 more cars made in spring and early summer '93 doesn't mess numbers too much.

Its ROW '93 which are more important as there were more of them. Total '93 ROW production was 621 GTS. 1/5 of them is probably manual cars. This means by the time when 1/3 of '93 ROW cars were made some 20-25 of them were manual gearbox cars.

Since some 40% of US cars were 5sp together these would mean maybe 40 manual GTS were made when 0096 US was at end of production line.

One other issue must be considered also. Porsche did some extra engines and this means engine numbers raise faster than number of cars made. But engines might have ended up into cars in different order than they were numbered.

Since engine number series started from 00501 I would expect original engine number to be somewhere between 85P00530 and 85P00570. Based on above logic last '93 manual cars might have engines in low 85P00700 range.

Besides engine number it would be good to check other expensive part, gearbox. Obviously it should be G28/57 and there is cooler in engine bay but migth be good idea to check box is GTS version.

cobalt

Why do you say this? My Radiator is original I have no doubt of that and the stickers are in the same location.

Don't know if it would help mine being the 73rd produced I can post my engine # when I have a chance to look. IIRC my production date was February of 1993 but will need to check.

Are we positive it is 40% of all US GTS's are 5 speeds or is this based on what we know about the 95 and 94's so far? I thought we were still awaiting Rixter on the balance of the 93's?

Also the M718 option used by Porsche worked by taking shells from the previous MY and installing drivetrains from the current MY. So the first 19MY 94 cars should have R coded motors.

First picture of my engine is from 2001 second is from 2005 I poke to both previous owners and they said nothing major was ever done and everything is original with all records forwarded.

cold_beer839

Rixter ran the build sheet on the '93 GTS that I'm buying and he gave me the exact engine and trans serial numbers. I will have them verfied during the PPI.

So far everything is looking good on that car.

Michael Benno

Hi, I am reviving an old thread because I am looking at purchasing a GTS and I would like clarification on when (Month year or VIN serial number) the 'stronger 2R' connecting rods were phased into the GTS production. In the quote above the author states the stronger connecting were phased in around 1994. However, the service tech info by year says says stronger and lighter connecting rods were phased in 1992 and no mention of a change in subsequent years. PET isn't very helpful since it only lists the most current part number (PN 928.103.008.04) for 1992 through 1995. And, I dont have TSB beyond 1993 so I am not able to verify a change. So any help you can provide is appreciated.

Mike

Rob Edwards

Here's the TSB on the 1R to 2R GTS rod changeover, which started with '94 5-speed engine # 85R00533, or '94 automatic engine # 81R50597.

Michael Benno

Thank so much Rob. Any concerns with the 1r rod reliability? Do they fail and if so under what sorts of conditions.

also, you you have a pdf resource for the post 1993 Tsbs? I’d be interested in reviewing. My files only go through September 1993

Rob Edwards

I don't have enough memory to recall all the conversations about 1R vs. 2R rods, Greg's comments in this thread https://rennlist.com/forums/928-foru...ata-point.html indicate he's only seen 1 rod failure but he's a proponent of the 2Rs whenever possible. But I'm not sure that whatever failures were occurring were primarily the rod's fault or [speculation] a consequence of the undrilled oil holes, carbon build up on the piston crowns, increased compression/impaired octane due to oil dilution of the air/fuel mix from increased blowby, and detonation that then killed the rods. [/speculation] . But it's likely Porsche saw something really worrisome or they would never have bothered to strengthen the rod design.

I'm about to embark on rebuilding a '94 GTS motor and will be using a set of 2R rods, for whatever that utterly non-statistically significant data point is worth.

jcorenman

I thought '94 GTS motors came with 2R rods...

Rob Edwards

They did, but only after September 14, 1993. Not sure how many August production '94s there were.

cobalt

That was an interesting read thanks for sharing Rob. I did not go back and read this entire thread so if I repeat myself ignore this. I cast and inspected aluminum and magnesium for the DoD, and aerospace industries from the 1980 to 2011. From my perspective Porsche was not close to cutting edge with their cast processes and did not properly prepare their magnesium parts prior to finishing. Both their mag and aluminum cast parts were nothing to write home about and in some cases I found embarrassing in quality. But that is most automotive parts, price over quality and limited QC/QA. Although the rods are not cast Aluminum or mag the differences visually from cast to forged are significant with all metals. From what I read and saw in Greg's thread I highly doubt that the rods had any special process and appear to be cast not forged. I am speculating here but I see differences that might be the result of different rod suppliers or casting houses. More than likely this might be what started the change. Most likely the 1R rods with the increased material came from different tooling and supplier. There are variations to the castings along with the lettering and markings, this is usually indicative of a different manufacturer. Although the later style 1R rod tooling looks to have more wear and tear than the earlier and the raised lettering has signs of repeated use and damage from ramming the sand and hitting the lettering with the rammer. I see variations like this quite a bit when one tooling/die maker interprets the drawings differently than another. Without actual measurements and testing to say one rod is significantly inferior to the other it is nothing more than an assumption. There are many threads about one being stronger and oiling holes not being drilled and the 93's having significant oil burning issues although I have yet to see any objective evidence this is the case. There are so many factors that could make one rod stronger or more brittle than the other irrespective of tooling or prior to machining. I suspect that the 2R revision was made to standardize all rods as not to have one version vs another used. It is possible if we had all early 1R rod engines in front of us that there may be more of the later style rods in the earlier engines than just the TSB is stating but that the engines as of 00533 all can be guaranteed to have these rods.

ROG100

These are waiting for my 93 GTS engine rebuild this fall.

Ladybug83

Interesting thread. Below is a pic of what I assume are the later 1R rods, with 2R shape, that went into my recent 5.4L M28/22 build. 944 stamped