Newbie Engine Question

D8design · 11-01-2010, 02:14 PM

Hi all

My engine Serial number is 6135316 and the number on the case is 901.101.102.7R
Can someone identify what I have? Thank you in advance!

bgyglfr · 11-01-2010, 02:24 PM

You have a 73T engine.

Bob Ashlock · 11-01-2010, 02:32 PM

It looks like a 1972/1973 engine. To get more specific, you need to find the "type number" that is located in the same general area as the engine number. This number will look like "911/xx" where "xx" gives the specific type of engine, (T, E, S) and what trans it was originally mated to. Once you have that, the info is available in Wayne Dempsey's engine rebuild book and other sources.

bgyglfr · 11-01-2010, 03:33 PM

Doesn't the 613 mean -

6 = 6 cyl
1 = t
3 = 73 year?

I didn't realize there was more to it. You learn something new every day.

Zeke · 11-01-2010, 03:53 PM

Quote:

Originally Posted by bgyglfr

Doesn't the 613 mean -

6 = 6 cyl
1 = t
3 = 73 year?

I didn't realize there was more to it. You learn something new every day.

You are correct. And the 5316 falls within the series made for the '73 1/2 CIS engines.

Grady Clay · 11-01-2010, 07:23 PM

The 1973 911T has three series of engines (six if you include engines for the Sportomatic transmission).

There are the:

911/59 RoW (911/67 for Sportomatic) 911TV (V = Vergasser) Zenith 40TIN carburetor.
These engine numbers are 6530001 to 6533239 and 6539001 to 6539197 for Sportomatic.

911/51 USA (911/61 USA Sportomatic) 911T MFI.
These engine numbers are 6130001 to 6131926 and 6139001 to 6139149 for Sportomatic.

911/91 USA (911/96 USA Sportomatic) 911T CIS (commonly referred to as ’73.5 911T).
These engine numbers are 6133001 to 6136092 and 6139301 to 6139502 for Sportomatic.

I hope this helps.

What is strange about this is Porsche is usually very fastidious about their numbering.
Why did they not simply change the 2nd digit to reflect CIS?
That second digit normally reflects the type engine:
1 = 911T MFI (and later CIS)
2 = 911E MFI
3 = 911S MFI
5 = 911T Virgasser
6 = 911RS 2.7 MFI
9 = 911RSR 2.8 MFI

Why didn’t Porsche use 4, 7 or 8 for the CIS engine?

I suspect it was to avoid re-certifying the engine for USA and/or California.
This was a mid-year engine change.
IMHO Porsche ‘sneaked’ it through in preparation for all the USA cars having CIS in ’74.
Continuing a sequence of engine numbers may have let them escape oficial notice.
They weren't secretive about this.
There are a lot of Factory service publications.

It would be interesting to read contemporaneous internal Porsche correspondence.
“Who knows what evil lurks in the minds of …” Porsche?

Best,
Grady

crustychief · crustychief's Garage

Thanks Grady, I learn something from nearly every one of your posts.

D8design · 11-02-2010, 04:58 PM

Thanks everyone for the valuable information!
Based on the info you guys provided, I think I have a 1973 911T with CIS before the Webber conversion by the PO.

One more question though, do I need to remove the old injector ports (circled in red) plug it with something or leave them alone? Please advise. Thanks again!

D8design · 03-21-2011, 07:23 AM

Can I upgrade my upper & lower leaky valve covers with a turbo covers from 1982 3.0 liter engine?
Thanks

ossiblue · 03-21-2011, 08:15 AM

Plug the ports (someone can offer the plug size and where to get them) before running the engine.

D8design · 03-21-2011, 08:27 AM

Sorry...I should have a new post for the valve cover question.

Grady Clay · 03-21-2011, 08:41 AM

Those (red circle) things are the old, un-used CIS injection nozzles.
You can find steel caps to seal these (10 mm x 1.5?).
The problem is the old rubber seals between the nozzles and heads tend to leak air.
Better is to remove the holders from the heads and plug the ports.

Yes, the later ‘Turbo’ valve covers are better at preventing leaks.
Make sure they are ‘flat’ on the sealing surface.

Best,
Grady