Part 7 - Fitting the Engine Block and modifying the Cylinder Head
All of the main aluminium panels are now finished and either rivetted in
place or fixed with clamps.
The car is looking a lot better, as you can see from the images above and
to the right.
Now is time to discuss the engine modifications.
The engine was previously a 2.0l Pinto from an old Sierra Sapphire. The
engine was dated by Ford to approximately 1983. The engine ran well, but
its history and details of condition of the the internals were unknown.
A month or so before starting work on the aluminium panels, we were offered another Sierra for free. This time the car was from a relative of the family and the condition of the car was known.
The car that produced the new engine and gearbox was a 1989 Sierra 2.0
GLSi. This car used the 2.0 Pinto in EFI form. The Pinto in these injection
cars is much improved to the original 2.0l and is known as the '205' unit,
due to the casting mark '205' on the engine block. The cylinder head design
is also much improved. Block, rod and crank strength is also improved over
the earlier design.
A much better basis for a performance engine.
Also, this engine runs on unleaded fuel with no modifications. Other Pinto engines require hardened seats to be cut into the head.
We decided that to be certain of the condition of the engine, to rebuild it and also have the following modifications carried out:
Oversize rebore by 1.5mm / .060" resulting a 2.1 capacity (2061cc).
Cylinder head surfaced and skimmed by 1.5mm / .060" rasing CR to 10.2:1
Crank reground and polished.
New oversize pistons fitted.
All new bearings fitted.
New oil pump.
New water pump.
New clutch and clutch plate fitted (2.0l clutch and plate).
Lightened flywheel.
We found out that the much lighter 1600 Pinto flywheel fits perfectly on the 2.0l engine, so instead of paying for the 2.0l flywheel to be lightened, we simply fitted that instead. The 1600 Pinto flywheel is 1/2 stone lighter than the 2.0 item. The only difference between the two is the 2.0 has half as much weighting on the reverse side as the 1600 item. Other than that, they are identical.
The 2.0iS head, as it is known, is a better design than the original 2.0 unit and produces more power. However, it can still be greatly improved with simple porting and bigger valves. We decided not to fit alrger valves, as this would require new seats to be cut and new inserts. We didnt really need this expense as the current valves were in very good condition.
Modifications to the cylinder head have been limited, therefore, to porting
and cleaning up of the inlet and exhaust ports.
Porting is quite easy to carry out, requiring only a drill and various cutting
stones. We also consulted the 'Power Tuning the Ford SOHC Pinto' book by
Des Hammil.
Basically, the ports are widened, the throats are smoothed of any casting marks, and everything is nicely radiused to improve gas flow.
With the engine and gearbox installed, it was possible to finally fit the
modified propshaft to the diff and gearbox. It also highlighted the fact
that the gear lever is far too forward to be comfortable. A remote shifter
or some kind of extension was required.
The answer was to add another shitfer base (the pivoting section that bolts
to the gearbox top) further down the tunnel and link the two shifter units
with a solid metal bar.
The results of the shifter modification can been seen the in the pictures above.
Although there is a little bit of play in the gearchange, all of the gears can be reached - the only problem gear is reverse; due to a worn selector on the base of the stick it is sometimes selected instead of first. We will rectify this by fitting a shift plate over the stick only allowing reverse to be selected if the stick is pushed right over.
Next: Finish the modifications to the cylinder head and complete the engine rebuild.
This page updated: 25/Mar/2007