Author Topic: seat marbella engine converted to fiat/seat 133 engine, running anti clockwise  (Read 3206 times)

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Offline sleurhut

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Hello GMR forum,

I got a Fiat/Seat 133 for daily use. When i got it i did a full service on the engine, drivetrain, brakes and suspension. The car is in pretty nice shape for something that is over 40 years old.

After running it for a while the Original engine lost oil pressure while idling at a trafficlight. Since this event the engine makes a tapping/knocking sound. probably bearing related problems due to oil starvation.

Bought a 133 engine from a vintage Lancia/fiat dealer in the north of the Netherlands. This engine had been sitting for about 20 years in a shipping container. The cilinderwall of the 3e cilinder got rustdamage and the 4e cilinder also got damage. If i want to use this engine it has to be overbored and new piston have to be fitted. A lot of work for a 840cc engine

After searching i found out you can use a 903cc seat Marbella engine for this application but you have to reverse the way the engine runs. A Marbella engine runs Clockwise. An 133 engine runs anti-clockwise.

I bought a very recent Marbella engine from 1998 with a very low milage (kilometers we call it in holland). Got it honed, measured and cleaned.

To change engine rotation i have to change the ignition, camshaft, waterpump and oilpump to counter clockwise turning ones. the blocks are the same.

Despite a lot of searching and measuring before I started the convertion to make sure it would work one thing was forgotten:

Fiat changed the stroke of the crankshaft to increase the number of cc's from 843 to 903cc.

 a 843cc got an 65x63.5 stroke.    The 903CC got an 65x68 stroke.

so the piston travels +/- 4.5mm more in the 903cc compared to the 843cc.'

My question is: can i still use my 133 camshaft? i'm afraid the timing on it wont work with the increased stroke. like it wont run in synth with the inlet and outlet stroke

Does somebody have some info on this or is this done before? how can i overcome this problem or is this not a problem at all?

greetings,

Joost van Beers

Offline olavr

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No problem, use your 133 camshaft. And the distributor together with the drive gears from the 133 will also work in the Marbella block.
The Marbella has a deeper oilpan, use the Marbella oilpump.
If you want to use an alu oilpan from a 850 coupe or spider, the 133 pump is perfect.
Good luck

Offline sleurhut

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just measured the lift heights of both camshafts, they are both a 10mm lift (dont have a micrometer handy out here but with some calipers it should me pretty accurate). thickness of the lobes from the side are the same and the height measured from top to bottom is exactly the same for both cams. but the shape of the lobe is a bit fatter on the marbella cam,

i will make a cam profile sketch and post it here,

if someone has some info on camshafts and which one to use for this engine please comment!

Offline sleurhut

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No problem, use your 133 camshaft. And the distributor together with the drive gears from the 133 will also work in the Marbella block.
The Marbella has a deeper oilpan, use the Marbella oilpump.
If you want to use an alu oilpan from a 850 coupe or spider, the 133 pump is perfect.
Good luck

Hello Olavr

so i can use the 843cc camshaft in the 903cc marbella engine? i will use the 903cc (larger stroke) crank, pistons and rods.

will it work with the increased stroke?

Offline sleurhut

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nobody? :(

Offline olavr

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Hello Olavr

so i can use the 843cc camshaft in the 903cc marbella engine? i will use the 903cc (larger stroke) crank, pistons and rods.

will it work with the increased stroke?

Sure, The fact that the Marbella 903 has a longer stroke will not affect the camshaft.
Another issue is that you maybe will want a hotter cam for your car than the std Marbella.

Offline sleurhut

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Hello guys,

I thought now i finished it why not post some pictures.

I did took a marbella engine, very low km's. stripped it down and did a full rebuild on it. New bearings, seals, cylinders honed and pistonrings. everything measured and made to specs. Dropped in the original 133 camshaft from an donor engine. standard lift and durations.

Fabricated a 4 finger exhaust from some kind of 850 unit and an imitation abarth damper. For more free flow and high rpm power. Put on a 30DIC with different jets to accomodate the cc increase.

I wanted to use the standard marbella cilinderhead since it had one done very little miles. Stripped the head and machined the hole in it to use an old style distributor like a standard 100 series engine has. Also had to drill an extra hole to mount my waterpump. i cant use an original pump because of the reversed engine rotation.

after all of this the swap was done in 1 day on a parkinglot,  i could have used a lift on my job but someway this was just as practical and it makes hell of a good story hahaha






engine got oil pressure very quickly and it ran great, only missed a bit of power in the low range, tuned out the accelerator linkage was not adjusted.

Ran it on the dyno, i made +/- 30 hp on the crank. AFR values wayyyy to rich. leaned it out by changing jets. eventuele on the last pull i punched it again and made 42 hp on the crank. not that bad!



When the engine was fully ran in i took it to the autocross circuit to test the track capabilities, or to be exact. the lack of those!

Next thing i will do is do a full suspension rebuild. Set it up to be fast on the slalom course. Its a very fun car to drive out there, the rear engine rwd gives you great adventages on some sharp corners and tight hairpins. you can steer the rear of it in just right to line up with the gates.



got a bit to confident and forgot the big problem with swingarm suspension:



i will put some pics on here when i'm finished fabricating an independant front suspension!




Offline olavr

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Nice job!