Differences betwen 69T & 70T

[blackbird225]

Some of you might remember my two rolling chassis saga from this year. I have a 70T chassis that I am still selling, and I bought a 69T chassis to put the engine and trans in. I now have my engine out thanks to the list and Brian specifically. But my 69 has 2 batteries. My 70 has one.

Should I buy just one?
Will the electrics in general be the same from car to car?
I am moving my H4 headlights over, do they have a special relay that I should take with me?
Any other perils in moving backward from 70T to 69T that will bite me in the ass?
As always, TIA.

Michael

[Wil Ferch]

Cars with two batteries can run instead with one....
No Porsche ever came with headlight relays ( should have !).....
Door handles are different ! Unique '69....and 70+ later......

Wil

[Grady Clay]

Michael,

Actually the wiring is very different from ’69 to ’70 and later. ’69 has many unique wiring features. You should get wiring diagrams for both and then make one specific for your car.

The headlight relays are available aftermarket and are very desirable.

Make sure the external voltage regulator follows the alternator.

The clutch is another large issue. The ’70 has a 225 mm pull type clutch and the ’69 originally had a 215 mm push-type clutch. It is desirable to keep the larger 225 mm clutch but it comes with the “Rube Goldberg” linkage. There are differences at the clutch pedal assembly also. This configuration will work just fine but you will need everything in perfect condition.

You are going to want to use the ’70 transmission case if you use the 225 mm clutch. Normally ’69 and ’70 have different gearing; A-F-M-S-Z in ’69 and A-GA-O-V-ZA in ’70. If you have both transmissions you can gear your ’69 for your use.

I am a proponent of dual batteries and having them well strapped down. This is particularly important in lightweight 911s. It serves the purpose of increasing the moment about the longitudinal axis and getting the weight forward using useful components (not cast iron weights.)

Does your ’69 still have the Bosch fuel pump and brackets in the front at the cross member? If not, bring the ’70 front mounted pump over.
By any chance does the ’69 have the return fuel line in the chassis? If not, now would be the time to install one even if not used. It is necessary for all FI engines. Plan ahead.

Theoretically if both are “T” then they should have the same brakes. If you should be so lucky that one has the aluminum “S” brakes, use them and the struts.

Most components are the same and directly interchange.
Which fuel tank is best?
Do either have the up-dated wedge-pin type struts and ball joints?
Is there any sign one rear suspension is in better condition than the other?
Sway bars?


What is your plan for some serious general maintenance on the new chassis?
Some important items are:
Brake rotors and calipers.
Brake hoses and master cylinder.
Pedal assembly, linkage, and cables
Wheel bearings and seals.
Shocks.
Ball joints and tie rod ends.
CV joints and rear wheel bearings.
Shift linkage.
Fuel tank and filter screen cleanliness.
Electrical connection integrity.
Doors, windows, latches, and lights.
and more….

Best,
Grady

[Wil Ferch]

Grady:
Wasn't the 71 with the pull-type clutch and strange linkage ?????

Wil

[Grady Clay]

Wil,

Yes, the ’71 also had the pull type clutch identical to ’70 with the same linkage. The ’69 had the clutch very similar to ’65-’68 with only minor differences. Of course in ’72 everything in the linkage changed with the 915 but it continued with the 225 mm clutch.

One of the remarkable things about Porsche’s engineering progression is the ability to up-date and back-date 911s. This is the fun and challenge.

Best,
Grady

[blackbird225]

Grady, thank you thank you thank you for answering.
Ok, the car was parked in a garage in 82. So everything is still in really great shape. I am moving the 70T's engine and transmission over, so the clutch is no problem. I plan on replacing the master cyl and rebuilding the calipers. CV Joints came with the 70T. Headlights came with the 70T. Pedal cluster is like new. Fuel tank is new, sender is new. Etc.
Problems....
The wiring for the two cars is TOTALLY different as you pointed out. This scared the *(&% out of me. I might not have bought this car if I knew that little tidbit. I don't see the CDI box, so I am assuming that 69's didn't even have one...
Can I "convert" the 69 to the 70's wiring? I hope you say it can be done... Let's just say I frowned when I popped the lid and my dreams of a "drop in" faded quickly.

Thanks again for helping me out

michael

[Grady Clay]

Michael,

It sounds like you have everything in hand except the wiring at the engine. Don’t let your hopes fade, this is easily resolved.
First, get the diagrams for ’69 and for ’70. I have the diagrams for ‘69E & S and for ‘70T, E, & S. Send me your e-mail address and I will send you scanned copies so we are looking at the same page, literally. These will be several Meg files, is that OK?

The absolute easiest solution is to find a good used engine wiring harness from a ‘69T, E, or S. I think the next easiest best solution is to make a small intermediate “adapter harness” from your 14-pin connector '70 engine harness to the 4, 5, & 6-pin connectors on the ’69 chassis. Next choice would be to make a new engine wiring harness or buy one from Porsche. Another choice would be to convert the engine compartment electrics to ’70 configuration – most difficult.
My philosophy is to do things right the first time. When things are done half-ass, they come back to bite you there. You want the wiring to be well documented and serviceable forever. It is easy to do this with your 35-year old 911. Make it so in another 35 years.

Can you post a photo of the electrical panel, etc. in the engine compartment of the ’69T?

I think your ’70 has a separate wiring harness for the CD ignition so that should be easy to swap over.

The first step is to do some on-line searching for a ’69 harness. A “T” harness would be best but an “E” or “S” would work just fine, you just wouldn’t use the MFI features.



While you do that, let’s discuss the clutch more.
While the engine and trans are out, you should separate them and inspect and lube things.
Pilot bearing surface on input shaft, inspect for damage.
Signs of input shaft seal leak.
Clean and lube release bearing guide tube.
Clean and lube the bore of release bearing.
Clean splines on input shaft. Very lightly lube (WD-40).
Does it have the updated pivot for the release arm? Clean and lube.
Are all the right parts there?
Is there any sign the release arm has been contacting the pressure plate?
I would recommend disassembling the clutch.
Inspect clutch disc for wear. Confirm it has a spring center, not rubber.
Test fit the disc on transmission splines. Make sure it slides smoothly.
Measure flywheel thickens, is in spec?
Inspect friction surfaces of flywheel and pressure plate for damage.
Inspect for any sign flywheel seal is leaking.
Spin and feel release bearing for any noise.
Inspect pressure plate fingers at release bearing for any damage.

If this were my project, I would summarily replace the pilot bearing, crankshaft seal, flywheel bolts, clutch cover bolts & lock washers, release bearing, transmission input shaft seal, and install the “dam” seal in the guide tube.

Properly reassemble everything.

I would replace the clutch cable.
Check that the plastic piece has been replaced with a metal part.
Inspect the support ring that is part of the transmission side cover.

The issue with the pedal assembly is the lever that the clutch cable clevis attaches to. The length of that lever changed between ’69 and ’70 I think. If so; you can have an unfavorable ratio where the clutch won’t operate fully. PET 6 shows the one for ’69 as 901.423.320.01 and for ’70 as 911.423.027.00. If the lever arm in the ’69 car is longer or the same, leave it alone. If it is shorter, replace it. In any case, this is a good opportunity to rebuild the pedal assembly. I am in favor of the OEM plastic bushings.

Please read these threads, there is a lot of good info. It shows the clutch release arm pivot update and the guide tube “dam” seal modification.
’70-’71 clutch
clutch cable for 70-71 901
and
'70-71 T.O. arm play?
and
http://forums.pelicanparts.com/porsche-911-technical-forum/166598-clutch-cable-70-71-901-a-post1520882.html#post1520882


On to other issues:

When you are removing the engine and transmission from the ’70, be very careful undoing the speedometer cable to not stress or damage the speedometer angle drive at the transmission. It may take several applications of “EZ Off.”

The same care with the oil hoses. What is the condition of the oil tank in the ’69? You need to clean it thoroughly. Does it have an oil level sender?

While the engine and transmission are out it is a good time to replace the plastic bushings in the throttle linkage bell-cranks at the engine and transmission. Clean and lube all the throttle linkage. The rubber throttle cushion should be replaced also.

Great that the fuel tank is new. What and where is the fuel pump?

Start collecting the necessary parts for reassembly now. You are going to need CV gaskets, new Schnorr CV lock washers, and much more.

Best,
Grady

[blackbird225]

WOW.....
I feel like I owe you some $$ now, gees. This is why I even attempt this project. This is what the internet was supposed to be for. Not just porn and Viagra peddlers, right? hehehe

The 69T has an intact wiring harness, but do I still need another one?
THere is a 70T partial harness on Ebay right now. $23 shipped. But its got those nice connectors included.

Here is what I have to work with on the 69.

You are seriously the man for helping out and writing a whole book for me/the list like this

MIchael

[blackbird225]

BTW,
PELASE send me the wiring diagrams. I was gonna beg the list for them later.

Don't care what size they are.

Thanks again X1 million
Michael

[Grady Clay]

Send me your e-mail address to gradyclay@hotmail.com. Wayne's system won't allow large files.

I'll post lower res versions so all can see.

Clearly someone has been tinkering with the wiring in the engine compartment. It may take some work but I think the easiest is to convert the engine to '69 configuration.

Best,
Grady

[copper]

Michael

Just to clarify one of your earlier observations...

69 was the first year for CD ignition systems. ONLY the E and S had CD boxes. The T, as a base model remained conventional.

Jim

[Grady Clay]

Guys,

Michael is going to need some photo documentation of the original configuration of a ’69. How about chiming in?

Here is the correspondence we had today:
Michael,
If it really has 40K miles, you have a real find. Be careful to not undo something original that can't be put back. This reinforces my thoughts about converting the engine wiring to original '69 configuration. Yes, I think it is an easy conversion; it definitely is NOT a nightmare. My admonition to you is to take your time and do it right. That will reward you in spades.

Keep taking photos and start a manual/scrapbook for the 911. There is a lot of value in documentation and provenance.

My remark about "tinkering" is based on the dangling wiring. The good news is that it appears that someone disconnected all the individual wires from the 9-pin connector rather than disconnect the connector (the one behind the engine). That makes it easier. Tomorrow I'll look and find the small alternator wiring harness that may be the only thing you need. Tell me the wire colors coming from the 9-pin connector at the rear of the engine bay.

Dealing with the clutch is your call. It depends on how competent the PO's mechanic was. If it were my 911, I would follow my previous post, possibly wasting some money and effort but having a reliable and proper functioning 911.

Why do you think you need to rebuild the calipers? I would replace the master cylinder and rubber hoses with OEM, lube and cycle the pistons in the calipers, and then see. I recommend you use OEM rubber brake hoses and not aftermarket SS hoses.

You still haven't answered my question about the fuel pump.

Don't sell your '70 roller for a while. There are many more things you may want to swap or save.

Attached is the relevant part of the '69 wiring diagram, I'll send more soon.

Best,
Grady



----- Original Message -----
From: michael
To: gradyclay@hotmail.com
Sent: Friday, November 12, 2004 1:53 PM
Subject: 69T 70T wiring nightmare

Hey Grady,

Thanx again for all of the help!

Just send them filez to this address. Does it really look like tinkering? That surprises me. The car has the original tube tires, original everyting incl radio except a shoddy repaint.
It only had 40K miles went put away too. I hope you are right when you say it can still get done fairly easily.

The clutch is new/ with a transmission rebuild 2K miles ago, but by the PO. I had planned to repack the cv joints and just drop it in. I also plan to rebuild all four brake calipers, replace the flexible lines with stainless and put in a new m\c. Also plan to put my new gas tank, sending unit in.
Already switched seats, retractible seat belts and headlights - PITA. Have new clutch cable, rebuilt pedal cluster.
DO I stil lneed to look for a 69T harness? Y
Michael

I want to see Michael’s project be successful and someone in another 35 years appreciate our efforts.

Best,
Grady

[Grady Clay]

Guys,

Who has photos of original '69 engine wiring?

Best,
Grady

[dafischer]

I'll be doing some maintenance on my 69T tomorrow. I'll take some shots of the wiring and post in the pm. It's pretty original, and hasn't had much PO "ingenuity" applied to it.

[dafischer]

Grady, any thing specific you'd like to see to help Michael out?

[Grady Clay]

Dave,

Thanks for the help.

I think the connector behind the engine (near the RR shock) is pretty straightforward and he has the engine side harness (dangling in his picture.)

He will bring with the engine the ’70 CDI harness so that is OK.

I think the issue is the alternator harness. In ’70 it is intergraded in the main harness but in ’69 it is a separate small harness. Looking at PET 6 it seems to be 901.612.037.10 for a Motorola alternator. He certainly should be able to find one somewhere.

If you can photo and sort out your wiring between the engine and the electrics to the left of the engine compartment, that will help. My lame memory is only so good.

Best,
Grady

[blackbird225]

You guys are the best.
Still unsure which plan of attack:
1) Map wire for wire from 69 config to a 70 connector for plug 'n pray?
2) retro fit each wire from the existing harness onto the 70 engine / CDI box ?

I plan on thoroughly cleaning the engine compartment tomorrow, then taking nice pics of the wire colors, and making a spreadsheet to list them. The finished product would be a neat thing to have around for future conversions...

Again can't say enough good things about you for all your help

Michael

[Grady Clay]

Michael,

Both your choices don’t deal with the issue of the main (red) wire from the alternator. On the ’70 it goes directly from the alternator, through the tin behind the engine to the battery wire on the starter motor. That extension to the engine wiring harness also includes the pair of wires to the back-up light switch and some wiring from the starter (yellow).
The ’69 has the big alternator wire (red/white) going to a single screw terminal (#60 “terminal bar” in the ’69 diagram I sent you) at the left of the engine compartment (just left of the stenciled number 12 in your first photo.) This is similar to ’68 and earlier. I think all the wires to the starter and back-up light switch just branch out of the main harness above the transmission.
This is where your and Dave’s photos will help.

BTW, in the photo of your transmission you have the back-up light switch dangling from the harness. You should unplug the two wires and reinstall in the transmission. Make sure the little pin is still in place in the transmission.

It may turn out that the bundle of wires zip-tied to the LR engine mount may be all that is needed.

What brand of voltage regulator is on the ’70? I see a Bosch voltage regulator on the ’69.

Be sure and look at the fuel pump set-up on both 911s.

Best,
Grady

[klaucke]

Grady, why did you suggest OEM brake hoses, rather than the stainless braided? I thought these were always preferable, and a slight "upgrade"?

[Grady Clay]

Michael,

Looking at that beautiful, clean magnesium transmission reminds me about the Factory coating.

Porsche originally coated the transmission (and the entire underside of the car) With Valvoline Tectyl 822. I copied the number off the drums at the Factory. It is a solvent based, amber, “one-season undercoat.” In fact it lasts many years if done properly. Porsche was (is) adamant about coating the magnesium parts with this stuff. I have seen unprotected magnesium parts simply disappear from corrosion. I have also seen properly protected ones look like new when re-cleaned. Every time we rebuilt a transmission it was recoated with Tectyl.

Tectyl is available in the States from Daubert Chemical Co. here: http://www.daubertchemical.com/main.taf?erube_fh=daubert&daubert.submit.getproducts=1&daubert.categoryId=1&daubert.productLineId=1
The current product is Tectyl 553.
I think it is distributed worldwide as a Valvoline product.

You cut (dilute) this with standard Stoddard Solvent to the consistency of thin house paint and brush it on. It comes back off with normal cleaning with solvent. I coat all external surfaces except mating surfaces (axle flanges, engine-to-trans surface, starter seating surface, etc.) If you have nice new anodized hardware, it will remain beautiful for years to come.


Another corrosion issue with the magnesium castings is “contact corrosion.” When Porsche changed to the magnesium casting, they also changed to cadmium plating on steel flat washers that contact the magnesium. This prevents electrolytic contact corrosion. You should always use new, well plated washers. I would always additionally dip them in Tectyl for added protection.
With the change from steel spring washers or split lock washers to flat washers, Porsche also changed to nuts with internal locking threads (looks like a Helicoil.)

Best,
Grady