1216cc foot gasket

[Huib]

Does anybody know the thickness for the foot gasket of the 818.130 - 1216 cc engine?

The reason I am asking is that I lack 0,35mm.

The stroke of the 1216cc is 2,7mm less than of the 1300cc and 1232 engines. The crank is thus 1,35 mm less off centre than the crank of the 1300 crankshafts.

To get the top of the piston level with the top of the cilinder as with the 1300's the 1,35mm would have to be compensated for by a conrod which would have to be 1,35mm longer than the conrod of a 1300cc engine. However the conrod is only 1,0mm longer.

The foot gasket in the current gasket sets is 0,47mm thick. On all the 1300's I have done this is the correct thickness to get the top of the piston level with the top of cilinder at TDC or at least nearly level. On the 1216 cc the piston would be 0,35mm under the top of cilinder at TDC with this gasket. The only solution I can see to gain the 0,35mm "legally" would be a thinner foot gasket.

The engine I took apart would have quite a story to tell if it could talk. The foot gasket was a 1300 cc gasket which I think to be wrong.

[Michael Beattie]

I suppose the question is, did the 1216 run a lower compression ratio, as standard ??

Or is the head "skimmed" a bit more to make up the difference?

I see according to the table in :-

http://www.alma.it/vanzettip/fulvia/fulviae.html

That the 1216 had a different bore from the 1232 & 1300, has it a different crown height?

Otherwise, I wouldn't have a clue, Huib ?

Cheers

Michael

[william]

The gasket is the same for al non 1600 engines and is about 0.5mm thick (check also the Tavola Ricambi)
The reason for this is the well known difference in expansion of the guss iron cilinderblock and the aluminum cranckcase. A 0.15mm gasket could simply not cope with this difference.
The compression of the 1100 and 1200 engines is both 9:1 and because they share the same head and stroke the difference must be in the pistons. Otherwise the compresion for the bigger bore 1200 would be higher.
A nice piece of side information is the fact that the 818.100 head was often used on 1300HF comeption engines just for the smaller combustion chamber. Only the ports needed to be enlarged. With stock HF pistons they could reach over 11:1 compared to 10.5:1 as standard 1300HF. (This trick was performed in classes were only original parts could be used)
In my 1216cc HF engine I discarted the 'foot gasket' altogether. I milled two chambers around the oilpassages to take an O-ring and glued the cilinderblock on the cranckcase with high quality jointing paste. So far no leakage what so ever but because the pistons reach 0.5 mm more in the bore the CR is upped. In your case the 0.15mm they will clear the block will be no problem as the headgasket is 1.3mm thick at least. most replacement gaskets are 1.5mm or more but that is another discussion.

[P. de R. Leclercq]

Interesting stuff - this sort of subject makes an excellent topic for club meetings etc., where Fulvisti can argue about such things.

First of course the gasket must compress, Huib, or was the measurement made on an old gasket?

We used William's approach successfully several times at Evolution Engineering; but there were four O rings: two for the camshaft feeds, one for the famous "spout" and one for the feed to the water-pump shaft.

One engine on which we did this was the infamous 1486cc project. This I shall be writing up on my blog before too long as I have found a photo and some interesting drawings.

Paul

[P. de R. Leclercq]

Very interesting about the 818 100 heads being used by the factory.

At that time, more compression meant usually, domed pistons. Of course this approach is no longer used in the best engines, since a flat topped piston means a shorter flame path and less total ignition advance is therefore needed.

And a piston with a high dome also affects gas flow - when both valves are open. This subject came up in the 1960s at BRM - see Doug Nye's BRM books and also Tony Rudd "It was fun"

This means that with flat pistons, in theory, one would need less overlap for a given result, all else being equal.

Paul

[Huib]

Nr 3 O ring must be for the tensioner.

Whether the gasket compresses or not is in this case not part of the issue. If it does, it would compress equally in 1300 and 1200 engines and still not account for the missing 0,35mm.

The head is an 818.100 head.

Distance between crankshaft and top of crankcase is the same for 1216 and 1300
Height of block idem
I put a 1300 and a 1216 piston on the same pin. Crowns appear to be at same height.

The 818.100 (1C), 818.100 (2C) and 818.130 (1216cc) have the same stroke.

CR of the 818.000 is 7.8. It's conrod is 1mm shorter (same length as for the 302/303).
818.100 and 818.130 have a CR of 9 and the longer conrods.

The crankcase of the engine is in bad shape: the nozzle is gone, welding was done around the hole for the hidden bolt, broken off bolts in the clutch housing, marks of hammering on various places. Probably someone forgot the hidden bolt and used the Russian tools to seperate block and crankcase.
Some days ago I dug up another 1216 crankcase, cleaned it and scraped of the remains of gaskets. Stupid enough I did not measure the thickness of the foot gasket but I do remember that it was not the black material as in todays gasket sets, but a light brown material.

[william]

See for a picture of the 818.340 engine with 818.100 head the bottom picture on page 166 of the yellow italian Lancia Fulvia book.
Huib, If the 1100cc 2C and 1216cc coupe/GT have the same CR , the same rods and head plus the same height of the cilinderblock then the difference MUST be in the pistons. Maybe a measurement of a rod with piston attached without having those parts in an engine is bound to have errors. 0.35mm is difficult to measure that way. I'm sure you would remember if you scraped of a 0.15mm thick gasket instead of one of 0.5mm thickness. I never noticed a difference on the 1100, 1216 and 1298 engines I took appart.

[Huib]

If the difference is in the pistons (like you I see no other options) I would expect it to be in the doming on the top rather than in the pin - crown distance.

I think the gasket I scraped off was thinner than the 0,5 gasket.

[P. de R. Leclercq]

Quite right - the tensioner... Obviously asleep yesterday...

"Probably someone forgot the hidden bolt and used the Russian tools to separate block and crankcase."

Ha-ha!

Paul

[P. de R. Leclercq]

This was, I think the practice at the time - cf 302 and 303 pistons.
Paul