Cosworth yb pistons into pinto

[Brisca665]

Hi guys, i have just bought some cosworth mahle yb pistons and h beam rods, my question is which way around to fit the pistons. They have a notch out of the skirt on one side and the pin is offset. Does the notch go to the front or rear of the engine. Or in other words does the pin offset go towards the intake or exhaust side of the engine ?
Many thanks.

[Graham]

cant remember off the top of my head, but it should be obvious if you look at the oil squirter position

[HonkyWhiteTrash]

The largest offset faces the direction of engine travel - in a Pinto this should be on the inlet side.

Also, marks or notches usually go to the front of an engine.

Are you building a Pinto Turbo as Cozzy pistons will lower your compression unless you've got a cylinder head with very small chambers.

[Brisca665]

Cheers. I was thinking that the pin would go to the thrust side ie exhaust side on a pinto. My thinking is to keep the rings square in the bore on the power stroke.
Yeh im building a pinto with an m90 supercharger blowing through a pair of weber 45 dcoe 's

[Graham]

the pistons were designed to be used in a forced induction engine, so surely best to fit them as intended? after-all they are not going to know whether they have a pinto head and supercharger, or a yb head and turbo pressuring down on them

[Dyno]

I suggest not to blow into Webers, when throttle plates fitted after the Eaton blower, you can get very high pressure on the inlet side of the carb. Best and far most easy way is to use suck trough setup. Some Eetons have a very large intake entry, try to mill off as much as possible and fabricate a new flange. Some other already have a nice intake small intake. The fuel mixture will also be very difficult to tune. Carbs do not understand denser air.

You can fit one Weber DCOE but I found it was not so easy to tune. 2x SU 44mm is very easy to setup. Also Weber 32/36 DGAV can be used as long as the power is not too high. Otherwise you need a Holley 350 or 450. Please note, you will need carburator manifold heating.

After the blower you have to make the exit entry as small as possible, lowest volume possible. Don't worry to much about air flow or "fast looking shape". From here the tube as small as possible to the inlet manifold. A simple single carb manifold from a Ford VV carb is fine. Also important to fit the blower higher as the inlet manifold and keep attention to the piping so the fuel dropped out of the air will run into the engine with gravity. This will minimise te risk to fuel collecting into the manifold and poor performance.

I've done it more than once, all the rest was simply not working. I once build a very old 1800 Volvo with blower and SU. Fuel consumption was as low as 11 / 100 kilometers, measured in a mix of traveling on and off the rally + rally stages !!!!! I did had t fit water injection to prevent pinking because I was using fair lean mixtures to keep fuel consumption low (this car was driven over motorway to rally's in Italy Spain, Portugal, made 60.000 Km in less than 2 years). Fuel consumption was important.

[theduck]

Price youd get selling the webers could well pay for efi conversion too.

[Dyno]

On a Blower engine, that would be a good option. Specially if you are not familiar wit carb tuning. You will not need any fancy throttle bodies, just a good old scrap throttle body will do the job. All you need is an ECU and wiring.

At the same time, you can put the blower about everywhere on the engine, not just as high as possible.