TheSamba.com :: View topic - The last 1300cc F engines were Dual Port?

Tue May 13, 2025 11:53 pm

Hello everybody,
this morning I started to work on an engine for a customer, a 1.3cc dual port with AS41 block.
While I was working on it something strange went to my eyes: the block is stamped "F".
At first I tought it was a reconditioned engine but then I also noticed that the numbers and the vw logo were present and seemed original:

After that I checked here on the samba, looking at the tabs the "F" engine production ceased in July 1970 after 2.140,820 units.
So my engine is very close to the end of production, merely 3000 units to the end.
Strange because F engine should have: single port, single pressure valve and not built on AS41 blocks.
It is a full finished double port engine, with the aluminum radiator, doghouse, three pieces intake etc etc.
So what do I have here? Being so close to the end of production it is possible that vw already made the new version and started to sell it marked "F" for the last units and then change the name in august with the new model year?

I wonder if the last "B" engines were the same and when exactly they started to make the dual port engines.

Does any one of you have a 1970 beetle to see other engines like that?

cheers

Wed May 14, 2025 3:16 am

Dual relief valve was introduced in 1970. So it is possible that your engine was originally single port but dual relief valve and later rebuilt as a dual port.

Wed May 14, 2025 10:08 am

Back in the 80's I had a 1500SP I tossed DP heads on. I don't remember swapping out P/C's. Would putting stock DP heads on a 1300 be possible?

Wed May 14, 2025 8:12 pm

You are in Italy. That was one of the countries where you didn't get anything larger than a 1300CC engine without paying a special tax. I imagine you will find a lot of 1300CC dual port engines there.

As for the engine discrepancy, you will need to look further. There has to be documents somewhere.

Wed May 14, 2025 11:31 pm

From this page on engine numbering:

Quote: Replacement cases
These cases were VW engine cases that were sold from VW but never issued in an actual production vehicle. All are dual-relief cases with 100mm oil passages.
F1 1300/1600
F2 1300/1600
DO 40hp if last digit is "X"
D1 40hp part
AD 1600
AK 1967-1974 1500/1600
AM 1600
AS Sometimes seen listed as Super Beetle case for 1973-onward

My question is whether the engine you are working on is actually a 1300cc (1.3L)? Does it still have the 77mm diameter pistons? Or are you calling it a "1.3cc" because of the F2 case?
If it is a VW replacement case it may never have existed as a 1.3L engine. :?

Thu May 15, 2025 8:24 am

I'd be interested to see what else is in that engine especially if it is stock and never been apart before.

Does your engine have flat pistons or the dome top ones?

Thu May 15, 2025 11:01 am

My March 1970 still has its original F code 1300 and its a dual relief case. Not sure if its an AS21 or AS41 case though.

The 1969 F code engine i bought for parts was a single relief case one, though only a few hundred digits older

Thu May 15, 2025 11:21 am

Luca5387 wrote: Hello everybody,
this morning I started to work on an engine for a customer, a 1.3cc dual port with AS41 block.
While I was working on it something strange went to my eyes: the block is stamped "F".
At first I tought it was a reconditioned engine but then I also noticed that the numbers and the vw logo were present and seemed original:

Side issue... that oil deflector plate is oriented wrong. You are not the first:
https://www.thesamba.com/vw/forum/viewtopic.php?t=644095
Should be:

Thu May 15, 2025 7:14 pm

One thing about the numbering system for serial numbers for upright Beetle engines for German made production line vehicles:

Single port were always one letter and 7 digits
Dual port were always two letters and 6 digits.

(type 3s got dual port before this numbering system change, so they werelsingle letter plus 7 digits)

The parts manual clearly shows the start of dual port heads at AB 000001 and AC 000001.

Thu May 15, 2025 11:00 pm

ashman40 wrote:

My question is whether the engine you are working on is actually a 1300cc (1.3L)? Does it still have the 77mm diameter pistons? Or are you calling it a "1.3cc" because of the F2 case?
If it is a VW replacement case it may never have existed as a 1.3L engine. :?

Hello,
This is actually a 1.3cc with 77mm dome pistons

But looking at your tab maybe this was a replacement case from vw, then rebuilt with DP heads and stamped after the original engine...

Thu May 15, 2025 11:02 pm

Zebedee wrote: My March 1970 still has its original F code 1300 and its a dual relief case. Not sure if its an AS21 or AS41 case though.

The 1969 F code engine i bought for parts was a single relief case one, though only a few hundred digits older

From this photo it's visibile the single port intake so, at least you have the correct heads.

Thu May 15, 2025 11:03 pm

glutamodo wrote: One thing about the numbering system for serial numbers for upright Beetle engines for German made production line vehicles:

Single port were always one letter and 7 digits
Dual port were always two letters and 6 digits.

(type 3s got dual port before this numbering system change, so they werelsingle letter plus 7 digits)

The parts manual clearly shows the start of dual port heads at AB 000001 and AC 000001.

Yep, that's the same you see in the tabs here on the samba. I did not know the numbers differentiation between single and double port tho.

Thu May 15, 2025 11:09 pm

heimlich wrote: You are in Italy. That was one of the countries where you didn't get anything larger than a 1300CC engine without paying a special tax. I imagine you will find a lot of 1300CC dual port engines there.

As for the engine discrepancy, you will need to look further. There has to be documents somewhere.

Actually the most common engine here also for the 70's is the 1.2cc for the beetle and 1.3cc on T2 (!) with mountain ratio gearbox as standard :roll:
But sometimes you can find 1.6cc beetles, rare tho...