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Discussion Starter #1
Hello,

I am asking your help for clarification about understanding what are the differences between 750 and 101 engine block for Giulietta Spider Normale and how someone can distinguish the differences.

Pictures are really appreciated.

Thanks

Carlo
 

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The easiest way to distinguish between 750 and 101 block is the serial number. The 750 block has a much rougher casting surface than a 101 block. The 750 main bearings are smaller than the 101 main bearings. I believe that the serial number is the easiest way to determine 750 or 101 and the year it was produced. The typical 750 Spider Normale block is numbered 1315.40001-45000. The problem with 1959 Spiders is that you could have a 101 engine with a 1315 number. I own a 1959 Sprint engine with a 1315 number and it is a 101 engine.
 

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Kuni,

I agree, but are these larger bearing 1315 blocks not identifiable by having a 6 digit engine number, unlike true 750 blocks which I think all had 5 digit serials?

Joe
 

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Gents an easier way is to check the location of the fuel pump, the 101 Interim car engines which carry the 1315 designation have the block mounted fuel pump, while the early or 'true' 750 engines have the head mounted fuel pump.

Ciao
Greig
 

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Discussion Starter #5
Hello,

Thanks a lot for the information. Unfortunately my block has no serial number on it. Speaking about dimension of main bearings, do I have to measure the diameter in the attached picture? Anyone know the diameter for 750 and the diameter for 101?

Carlo
 

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Hi Carlo

Look on the outside "here" - if it has a fuel pump mounting on the timing cover it's a 101 series block, if there is no fuel pump mounting it's a 750 Series block.

Easy - see the difference in the second picture

If it's a 101 Series with the side mounted fuel pump then almost everything internal from the 105 Series 1300's will fit + most of the gaskets. If it's a 750 Series, then you can multiply the prices by 4 and add several months if not years to your search for parts.......

Ciao
Greig

750B's
750D's
750E
10102's
10103's
10109
 

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Hi guys,

Other than the engine number itself, are there any visual/internal differences between a 1315 and 101 engine block?

Many thanks,
Alex
 

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Not sure if this helps but the head studs are shorter on a 750 block than on a 101 block.

I have a (rebuilt Veloce) engine with a 750 block and a 101 head. The head was machined to be able to use the shorter studs.

But I don't know the stud lengths of either the 750 or 101 block.
 

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750 vs 101 Giulietta block

The principal difference in the engine block is the main bearing size.
750 series is 60.4mm
101 series is 63.4mm

This is the size of the bearing cap and block journal without bearing shells inserted.
There are other differences but not easily noticed, a 101 head can be put on a 750 block as noted by Biba, so that can add to the confusion.
over the years many changes could have been made, but the main bearing size will really be the first step in confirming the type of block that you have.

DaveB
 

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The principal difference in the engine block is the main bearing size.
750 series is 60.4mm
101 series is 63.4mm

This is the size of the bearing cap and block journal without bearing shells inserted.
There are other differences but not easily noticed, a 101 head can be put on a 750 block as noted by Biba, so that can add to the confusion.
over the years many changes could have been made, but the main bearing size will really be the first step in confirming the type of block that you have.

DaveB
Can a 750 block be bored out to take a 101 crank?
 

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Yes, but that's not the way to do it. Use a 101 crank and cut the mains to 750 size. Use standard 101 rod journals and stronger 101 1300 conn rods.
We found that most 750 blocks were not as tough castings as 101, and material removed from 750 blocks anywhere just made them more "rubbery". Stiffening a 750 block with a 101 crank and 101 head does help, as does a 2 piece cast veloce sump.
Just my opinion from my experience.
 

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Hi guys, becouse I see you are enthusiast of the Giulietta 750 and 101 I would report you that I have on sale a Giulietta 750 crankshaft absolutely new. If someone is interested in, can search and type on this site "Someone is looking for a giulietta crankshaft new (early type)?" So you will see my ad and the attached pictures. The crankshaft is in Italy. Sorry, my english isn't so good.
Best regards to everybody!
 

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I would use the proper crankshaft in either a 750 engine or 101 engine. I spoke to Marine Crankshaft located in Southern California and they can weld up an undersized crank or machine a new billet crankshaft. I have a complete 1959 750 Sprint motor for sale on eBay and also have another complete 1959 750 Sprint motor that I might sell. The two motors have 0.010 crankshafts.
 
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