900 Bluebell the 900e Amigo

timmycm850 · Apr 23, 2019

Gary50 said:
Connie's engine is also a GBC with alloy head - 900T's should have had the GF.

I had always thought that it was the original one when it came out of the factory (cars made in the 70's often had different parts depending on parts shortages) but I've just checked the engine number against the V5 and they are different - assuming the engine number is the one stamped under #1 spark plug? There was no mention of an engine swap when we bought her in 2001, so I'm assuming that the previous owner didn't bother to tell the DVLA.

According to the Haynes manual the 900T came with the Weber 30 ICF 20/250 whereas the 850T had the 30 ICF 15 (the one fitted to Connie as well).

Hi guys

100gbc is an 850 sport coupe (series 2/3) block and the engine number is normally on the machined face above and to the left of the timing chain cover, the seven or eight digit number cast into the block under plug 1 is a block part number and often the 100gbc blocks start with 4 and end in 141, the heads should also be cast with 100gbc in the middle of the top of the exhaust flange area, the coupes would normally run with a weber 30dic carb with two venturis at 23mm each, The 30dic carbs from series 1 850 coupe will have a smaller venuri size of 21/23, so running with a 30 ICF wont give you the full 47 or 52 hp and also you may lose a bit of the low torque(?) of the 100gf van engine as the 100gbc camshaft timing is longer and the carb is only a single choke.

ive never heard of a cast iron 850/900 head, if poss please show image of it. intruiged?

Gary, 850 coupe accelerator cables are slightly shorter than 900t types, you can replace the outer sleeve only of the accelerator cable as this normally corrodes, a metre from a bike shop is normally enough and you can carefully remove the solid ends from your own sleeve, sand your existing inner cable with a bit of oiled 400 grade paper to remove any surface corrosion before fitting the new sleeve, you dont have to remove the whole cable to do this just the rear outer piece.

just to fill you in i purchased my first 850 in 1989( an s3 coupe), since then ive not been without one and now have
1966 s1 coupe
1970 lombardi
1973 s3 spyder
1979 900t purchased 2015 i think
gamine

fiat500 · Apr 23, 2019

timmycm850 said:
ive never heard of a cast iron 850/900 head, if poss please show image of it. intruiged?

Tim...all that information is really useful and gratefully received. n:worship:n

My cast-iron head doesn't exist except in my dimly-lit memory. I was given a box of S/H bits when I bought the van and only raked through it today; so I have another alloy head, an earlier ICF carb., loads of thermostat housings, a brake master-cylinder which still has the golden anodising on the surface and various other bits which I can now see being quite useful.

I have seen the engine number and I'll look for markings on the head.

timmycm850 · Apr 23, 2019

fiat500 said:
Tim...all that information is really useful and gratefully received. n:worship:n

My cast-iron head doesn't exist except in my dimly-lit memory. I was given a box of S/H bits when I bought the van and only raked through it today; so I have another alloy head, an earlier ICF carb., loads of thermostat housings, a brake master-cylinder which still has the golden anodising on the surface and various other bits which I can now see being quite useful.

I have seen the engine number and I'll look for markings on the head.

Hi Peter.

great. a number of thermostat housings is good as they can turn to powder sometimes especially the small outlet tube to the temp sender. great to have some spares,

Tim

Classicandy45 · Apr 25, 2019

I haven't checked numbers, but have noticed a big difference in water pumps, I.e. mine(and my spare engines) are four bolt, yet most parts listings come up as 3 bolt?

timmycm850 · Apr 26, 2019

Classicandy45 said:
I haven't checked numbers, but have noticed a big difference in water pumps, I.e. mine(and my spare engines) are four bolt, yet most parts listings come up as 3 bolt?

Hi Andy

yes basically all 843 engines upto 1968 are 63.5mm stroke and 3 bolt mountings for the waterpump, 903cc engines are from 1968 are 68mm stroke and 4 bolt mounts for the waterpumps, the engine blocks differ in height by about 7 or 8mm height as well.

4 bolt pumps are much less available, some reputable companies are doing quality rebuilding of the existing pumps based on your core if you need one or on an exchange basis.

tim

rallycinq · Apr 26, 2019

How does the water pump differ between the 903 and the 899 (which is a sleeved down 903)

D

timmycm850 · Apr 26, 2019

rallycinq said:
How does the water pump differ between the 903 and the 899 (which is a sleeved down 903)

D

both these bolt flanges are angled
3 bolts on 843 100g engines are in a triangle bolt pattern with two at the top
4 bolt on 903 100gb engines are a square bolt pattern.

these bolt flanges are square onto the engine
3 bolt on 903/899 100gl and A112 engines are like the 4 bolt square pattern with the bottom right fixing missing, ( like an upturned L)

it gets even more complicated when you introduce the engines that seat made for the 133 and 127 fura's

Tim

Gary50 · Apr 26, 2019

I've just looked on Ricambio (other suppliers are available

), there is quite a difference in the price between the 3 bolt (£143.94) and 4 bolt (£474.00) versions - as is typical I have the 4 bolt version

However, assuming that it's just general wear there is an overhaul kit that fits either version for £83.94.

Has anyone here carried out an overhaul of their water pump and if yes is it something that you would advise an average enthusiast to avoid? Or relatively straight forward?

Are there any special tools required?

timmycm850 · Apr 26, 2019

Gary50 said:
I've just looked on Ricambio (other suppliers are available ), there is quite a difference in the price between the 3 bolt (£143.94) and 4 bolt (£474.00) versions - as is typical I have the 4 bolt version

However, assuming that it's just general wear there is an overhaul kit that fits either version for £83.94.

Has anyone here carried out an overhaul of their water pump and if yes is it something that you would advise an average enthusiast to avoid? Or relatively straight forward?

Are there any special tools required?

Hi Gary

its very easy to break the soft rear casing taking it apart, Middle Barton Garage in Oxfordshire do an exchange basis on the 4 bolt ones, not sure what the cost is but it might be worth a look at or a call to find out.

Tim

Classicandy45 · Apr 29, 2019

The mechanic who fitted the overhaul kit, messed up first attempt, complaining the spindle threads were made of plastercine (but just looked mushroomed by application of hammer to me!). Anyway, a 3bolt spindle, and another overhaul kit later and job was done.

Gary50 · Apr 30, 2019

Classicandy45 said:
The mechanic who fitted the overhaul kit, messed up first attempt, complaining the spindle threads were made of plastercine (but just looked mushroomed by application of hammer to me!). Anyway, a 3bolt spindle, and another overhaul kit later and job was done.

Just doubled checked the pricing, £474 is for brand new old stock. There is a reconditioned option for £300 - both require the old pump back.

One alternative I'm considering is to switch to an electric pump, as I have already switched to an electric fan. The basic set of bits for the conversion are around £150 to £250 (depending on type). However, getting an adapter for the engine block (where the pump currently fits) may be a problem.

Has anyone carried out an electric water pump conversions before?
And if so can you provide details/photos?

Vin · May 1, 2019

I just thought I'd mention that the 100GBC coding was certainly a code for the 850 Sport Coupe as Tim has stated, but by the early seventies all 903cc blocks were being stamped 100GBC regardless of what they were intended for (this was something I remember reading in an old Fiat document, many moons ago). I discovered this at the time I rebuilt the engine in my van as the original engine (the numbers matched the documents) and the two spare units I had were all stamped 100GBC on the blocks. I thought I had 3 Sport coupe engines!!! As with many things the reality was somewhat different...

fiat500 · May 1, 2019

Vin said:
As with many things the reality was somewhat different...

Well said.

I was coming to the same conclusion, having seen quite a few images of engines on vans embossed with the exact same lettering. It's better from the restoration point of view otherwise I would have difficulty being sure that the manual and parts lists applied to my engine.

I've already cocked-up as I got hold of a reasonably bargain set of timing-gears and chain under the correct kit parts number but find they are very similar but very different.:bang:

Bogged down at the moment replacing some very rusty "metal" on the floor of my 500 which was a brand new floor-panel fitted in 2009. :bang::bang::bang:

timmycm850 · May 1, 2019

Vin said:
I just thought I'd mention that the 100GBC coding was certainly a code for the 850 Sport Coupe as Tim has stated, but by the early seventies all 903cc blocks were being stamped 100GBC regardless of what they were intended for (this was something I remember reading in an old Fiat document, many moons ago). I discovered this at the time I rebuilt the engine in my van as the original engine (the numbers matched the documents) and the two spare units I had were all stamped 100GBC on the blocks. I thought I had 3 Sport coupe engines!!! As with many things the reality was somewhat different...

Now that makes for interesting reading, If that's the case then its possible that some "100GBC" engines out there are from Vans and so will have the shorter camshaft timing at about 242 degrees rather than camshaft timing of a sport coupe at 256 degrees, I guess the only way of really finding out is the paint dab colour on the camshaft based on the model it came from.

This could be why a certain engine of mine marked 100gbc doesn't seem to be as lively as some others, its likely that i will be looking at a camshaft closely in the next few days

Hmmm interesting reading.

Tim

timmycm850 · May 1, 2019

fiat500 said:
Well said. I was coming to the same conclusion, having seen quite a few images of engines on vans embossed with the exact same lettering. It's better from the restoration point of view otherwise I would have difficulty being sure that the manual and parts lists applied to my engine.

I've already cocked-up as I got hold of a reasonably bargain set of timing-gears and chain under the correct kit parts number but find they are very similar but very different.:bang:

Bogged down at the moment replacing some very rusty "metal" on the floor of my 500 which was a brand new floor-panel fitted in 2009. :bang::bang::bang:

Hi Peter

On the gears hat you received that don't fit, is the gear that fits on the crankshaft much thicker by about 8mm, I'm wondering if the gears you recieved are for a 100gl engine which has a different oil system.

Tim

fiat500 · May 1, 2019

timmycm850 said:
Hi Peter

On the gears hat you received that don't fit, is the gear that fits on the crankshaft much thicker by about 8mm, I'm wondering if the gears you recieved are for a 100gl engine which has a different oil system.

Tim

Hi Tim, I think the gears are actually the same, the chain would fit either set and the gears will actually fit; both on the crankshaft and the camshaft. The drawback is that the central boss on each is thinner (I'll double-check with images tomorrow). A thick spacer came with the kit but I can't see any combination of placements that aligns properly. :bang:

fiat500 · May 7, 2019

Classicandy45 said:
The mechanic who fitted the overhaul kit, messed up first attempt, complaining the spindle threads were made of plastercine (but just looked mushroomed by application of hammer to me!). Anyway, a 3bolt spindle, and another overhaul kit later and job was done.

Having just dismantled my pump I can sympathise with the mechanic.

The threads are made from Plasticine and a 34 year-old pump does not come apart according to the book instructions.

After trying to get away with my soft-headed hammer I gradually had to go up to a big, heavy thumper and consequently the threads on the shaft, although usable, are a bit manky. I also fell victim to the broken flange on the side housing...I have an escape plan for that.

But it crossed my mind that possibly a brand-new, three-bolt pump could be salvaged for parts because they can be bought quite cheaply from some online sellers......cheaper than the bearing overhaul kit. It's just that being pattern parts it's possible that the dimensions of the internals are different.

Where did you get your three-bolt spindle from Andy?

fiat500 · May 7, 2019

As mentioned above, here are most of the components of the water-pump. I've now managed to extract one of the woodruff-keys which seemed permanently embedded and I'm soaking the pump body in a mild solution of phosphoric acid and degreaser. I already cleaned out the thermostat-housing in the same way, but I'm being careful not to leave it too long; I only want to remove the rust and salt deposits and not to dissolve the whole assembly.

I'm trying the same technique with the radiator, but I think I'm safe to leave that longer term. The radiator has the advantage that because it is buried so deep and protected by cowlings it has sustained no significant external damage to the fins; unlike modern cars where I always find that dealership garages helpfully flatten the fins with the powerwash at every service.:bang:

I was going to use the chain of my new, mis-ordered timing-gearset on the old sprockets as they don't seem worn. But there is a bit too much side to side movement so the 850 set will go back on eBay and I'll order a new 900e set.

I didn't plan to get so deep into this at this point but like the rest of the van the engine seems to have suffered neglect and bodged repairs which might as well be fixed properly whilst I'm at it.

rallycinq · May 9, 2019

Better to do it while its out, rather than later.

Good work

D

Gary50 · May 12, 2019

timmycm850 said:
Hi guys

100gbc is an 850 sport coupe (series 2/3) block and the engine number is normally on the machined face above and to the left of the timing chain cover, the seven or eight digit number cast into the block under plug 1 is a block part number and often the 100gbc blocks start with 4 and end in 141, the heads should also be cast with 100gbc in the middle of the top of the exhaust flange area, the coupes would normally run with a weber 30dic carb with two venturis at 23mm each, The 30dic carbs from series 1 850 coupe will have a smaller venuri size of 21/23, so running with a 30 ICF wont give you the full 47 or 52 hp and also you may lose a bit of the low torque(?) of the 100gf van engine as the 100gbc camshaft timing is longer and the carb is only a single choke.

ive never heard of a cast iron 850/900 head, if poss please show image of it. intruiged?

Gary, 850 coupe accelerator cables are slightly shorter than 900t types, you can replace the outer sleeve only of the accelerator cable as this normally corrodes, a metre from a bike shop is normally enough and you can carefully remove the solid ends from your own sleeve, sand your existing inner cable with a bit of oiled 400 grade paper to remove any surface corrosion before fitting the new sleeve, you dont have to remove the whole cable to do this just the rear outer piece.

just to fill you in i purchased my first 850 in 1989( an s3 coupe), since then ive not been without one and now have
1966 s1 coupe
1970 lombardi
1973 s3 spyder
1979 900t purchased 2015 i think
gamine

Hi
I've finally found the engine number - top left above the timing chain cover as suggested. It is quite faint and had a thin layer of grime over it hence why it was easily missed.

Stamped above the engine number (original by the way) is 100 GF .000 - so the GBC block casting number ties in with what had previously been suggested about most of the later blocks being stamped GBC regardless of where they ended up.

Reading the Haynes manual the GF engine has a 7.9:1 compression (the GBC is 9.5:1). From what I've read elsewhere on the Internet the lower compression should make it more compatible with unleaded petrol - less risk of pre-detonation etc.

If correct (can anyone confirm?), I'm happy to live with fewer horses in favour of the ease of being able to fill up at the pumps without worrying about additives etc.

900 Bluebell the 900e Amigo

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