Head comparison

[AlleyNiki]

Hi folks, greetings from Japan.

I'm sure this has been discussed at some point. Could anyone direct me to a post / link where the standard a/c 126 head is compared with the Panda 30, for port size and shape, etc?

I'm trying to decide whether it's better in the long run to have a pro reshape the ports in the standard or to get a Panda 30.. if indeed the ports need to be re-shaped.

Sorry if my question sounds stupid, I am very much a novice when it comes to "engine head stuff."

Thanks guys, great to see you all here still.

Alastair

[DEYAN IYI]

"Insid" the Panda head is the same like 650E, except the bigger inlet valve 34mm vs. 32mm (same size like in Bis). The rest is the twin inlet porting, so you will need another manifold and carb.

Panda head plus normal carb is always better than 126 head with original carb. If you want to play with the original head, go for 650E. You can put Bis inlet valves, or Cinquecento 700 (35mm). And get rid of the original so called carb.

Here is the shape of the old type of heads (up) and 650E, Panda 30 (shown on the picture), also Bis and CC700.

[AlleyNiki]

Thanks for the great info! At work ATM so the filter is preventing me from seeing the images, but I'll check them out once I'm back home. 

Alastair

[AlleyNiki]

"Insid" the Panda head is the same like 650E, except the bigger inlet valve 34mm vs. 32mm (same size like in Bis). The rest is the twin inlet porting, so you will need another manifold and carb.

Panda head plus normal carb is always better than 126 head with original carb. If you want to play with the original head, go for 650E. You can put Bis inlet valves, or Cinquecento 700 (35mm). And get rid of the original so called carb.

Here is the shape of the old type of heads (up) and 650E, Panda 30 (shown on the picture), also Bis and CC700.

OK Deyan, so the head on the top is the original 126, while the 650E / Panda is on the bottom, is that correct? I know that the garage I bought my 126 from replaced the head with a new one a couple of years back. I don't know if it's a 650E or not. I didn't even know there was a 650E, never heard of it!

So what carb do most people around here go for? I've heard of Dell'orto 40's and Weber 40's being used. I checked prices as well on the online stores.. some pretty high priced stuff there.
 
Is a dual throat carb necessarily better?

Thanks for taking the time to photo / respond BTW!

Alastair

[Rusty's Uncle]

The later 126 cylinder heads have some letters along with 650 on the casting where it is visible. Just 650 in that cross hatched area will be an earlier head I believe. If you went for a Panda 30 head then you have to decide weather to machine away a lot of metal to make the head fit the cooling tin ware, build some custon tin ware or get the tin ware from a Bambino engine.

[grubscrew]

 .. yes the tin ware issue. I spent ages adapting the original cowling to fit, and make it look as though "nothing is different" look. It can be done with patience, it looks good too, still using the original cooling flap, although some enthusists remove this bit. But all in all its a fiddly old job.Mike.

[DEYAN IYI]

Hi, Alastair!

Yes, on top is the older shape combustion chamber (pre 1984). From 1984 to 2000 all the 126 are with this one. The 650E came in 1983 (E means economy), that differs from the older types by the head, 8,0:1 vs 7,5:1 compression ratio, other camshaft, different jetting, exhaust and wasted spark ignition. All the FL (face-lift) models 1985-1994 have this engine. The EL model 1994-2000 is the same, except the nanoplex ignition, jetting and exhaust. The ELX model with cat system is the same, except the exhaust and jetting. After 1991 all the 126 valve seats are ok with the unleaded fuel. (The info must be about correct.)

About the carb, for sure the twin ones are one of the best options. I'm not convinced if they are pretty worth over a single port head (not talkin abouth the wow-effect), but for Panda can't be better. I've prepared a Dellorto for mine, but the needed tools, parts and jets to run it myself are more than 300 pounds from http://www.dellorto.co.uk/. For starting point I'll use the jettings of some Alfa Romeo 1300 models. Other problem is that very few people are into the twin carbs, so you will have to learn as much as possible, get the tools and try to jet and adjust the carb. Would be easier if you have bug maniacs around, some of them are playing for decades with it.

The twin carbs give about 10% more power on an engin with progressive carb. The progressive one (like the ones in Panda 30, Bis, Cinquecento 700) is good enough for the 126 if you are not after the max power. If you get the Panda head, you can use the original manifold and carb. Only the manifold must be machined a bit, cos in Panda the engine is declined.

 If you use Panda head/manifold/carb and the pre 650E standard camshaft adjusted with 5* from the big timing chain wheel, you will have a Panda 30 engine in your 126, that means 30hp at 5500rpm or at 120km/h

Greetings! To Japan as well!

Deyan

[AlleyNiki]

Hi, Alastair!

Yes, on top is the older shape combustion chamber (pre 1984). From 1984 to 2000 all the 126 are with this one. The 650E came in 1983 (E means economy), that differs from the older types by the head, 8,0:1 vs 7,5:1 compression ratio, other camshaft, different jetting, exhaust and wasted spark ignition. All the FL (face-lift) models 1985-1994 have this engine. The EL model 1994-2000 is the same, except the nanoplex ignition, jetting and exhaust. The ELX model with cat system is the same, except the exhaust and jetting. After 1991 all the 126 valve seats are ok with the unleaded fuel. (The info must be about correct.)

About the carb, for sure the twin ones are one of the best options. I'm not convinced if they are pretty worth over a single port head (not talkin abouth the wow-effect), but for Panda can't be better. I've prepared a Dellorto for mine, but the needed tools, parts and jets to run it myself are more than 300 pounds from http://www.dellorto.co.uk/. For starting point I'll use the jettings of some Alfa Romeo 1300 models. Other problem is that very few people are into the twin carbs, so you will have to learn as much as possible, get the tools and try to jet and adjust the carb. Would be easier if you have bug maniacs around, some of them are playing for decades with it.

The twin carbs give about 10% more power on an engin with progressive carb. The progressive one (like the ones in Panda 30, Bis, Cinquecento 700) is good enough for the 126 if you are not after the max power. If you get the Panda head, you can use the original manifold and carb. Only the manifold must be machined a bit, cos in Panda the engine is declined.

 If you use Panda head/manifold/carb and the pre 650E standard camshaft adjusted with 5* from the big timing chain wheel, you will have a Panda 30 engine in your 126, that means 30hp at 5500rpm or at 120km/h

Greetings! To Japan as well!

Deyan

Hi Deyan, thanks once again for an informative response! 

I may just leave buying a super duper carb until later, but I would like to run the Panda head with the Panda carb. I'm guessing you mean the engine is on a slant, so the manifold has an to keep the carb levelled? If so, that's pretty clear.

My car is a 1989, therefore I must assume I don't have the old type of camshaft. Do I need the old camshaft if I want to use the Panda setup you mentioned with the 5* (degrees?) adjustment?

Thanks once again!

Alastair

[DEYAN IYI]

Hi, Alastair!

The pleasure is mine!

Sorry for my gipsy english Anyway, you got it right.  

I have no info about the real effect of adjusting the 650E cam (except on theory). In your case (if you don't perform an ultimate tuning), better keep the original camshaft without adjusting, unless you have aroud a perfect or a brand new old type one. If you spend money on a brand new one, better purchase a sporty one about 290° for a daily driver.

Compare here:

Standard 600/650cc ... 26°/57° - 66°/17°  (263°-263°)
Panda 30 .................. 21°/62° - 61°/22°  (263°-263°)
New type 650E ...... 18°30'/53°30' - 72°/24° (252°-276°)

Advanced timing - torque at low RPM
Delayed timing - torque at high RPM

And here is how to reshape the holes to play adjusting.



Actualy on the picture is CC700 chain (the engine turns anti-clockwise). For ours must be drilled to the right  http://www.126fan.pl/www/images/walrozrzadu/fazowanie_walka.jpg

PS - whatever you do, you'll have to throw away the original exhaust.

 

[AlleyNiki]

Fantastic information,  Deyan! Thanks so much for this.