Technical Sump bolts Thread?

[ClassicFiat500]

Can anyone help me locate the THREAD of my sump bolts i have removed my 4 litre sump to fit an oil temperature sender, however I noticed 2 of the sump bolts missing ( naughty) plus a couple fairly loose ones, the length is 27mm & diameter. 5.7mm But not sure what the thread they are!, as I have to order these on line i want to make sure I order the correct thread.
I also thought if I am going to order a new set of 16 I would order them with Alan key fixings as there is very little space between the fins on my Abarth sump to get a comfortable 10mm socket in.
Looking on the top of the bolt it says D6 8.8 and take a 10mms socket.I
All answers very grateful.

 

[lazylobster]

Hi, some more informed person will be able to advise. But a kit is here:

https://www.ricambio.co.uk/sump-bolt-washer-kit-classic-fiat-500-126

Other vendors will also be able to provide.
R

 

[jackwhoo]

M6 thread

 

[the hobbler]

The thread for the sump afixing bolts is 6mm x 1mm (pitch). If the thread has gone on the crankcase, there is enough 'meat' around the hole to go up 1 size to 7mm x 1mm. The appropriate hole in the sump has to be opened up--7.5mm should be big enough to give you a bit of 'wriggle' room.
I use cap-head (aka, Allen key) screws to secure my sump (3-1/2litre ally) to my crankcase, using a silicon sealer instead of a gasket. If sealer is use, apply it carefully to just the outer half of the contact surface so that no sealer is squeezed out into the sump. If you DO decide to use a gasket, use the 'rubberoid' type, NOT the cork variety. To secure the screws I use a 'shakeproof' washer AND the original Fiat 'oblong' washers. When using a sealer, these screws can be done up tight; if using the gasket, you have to 'feel' how tight they are, basically untill the gasket JUST begins to spread.

 

[jackwhoo]

To avoid damage to these small threads I use a screwdriver handle with a square 1/4 inch drive fitted to a 10mm socket to tighten .

 

[the hobbler]

Sorry, forgot to mention---the appropriate screws can be ordered from "Westfield Fasteners"---you will get 1st class service and the parts at a sensible price. I use the stainless cap-head screws. Look through your collection of nuts,bolts, screws and washers prior to ordering---Westfield can supply just about all that you will require of these parts.

 

[ClassicFiat500]

Great answer from everyone I knew I could rely on the Forum thanks for your replies an so fast. Now just have to order them!

 

[Toshi 975]

Great answer from everyone I knew I could rely on the Forum thanks for your replies an so fast. Now just have to order them!

Order screws to suit the thicker flange of the alloy sump not ones that suit a thinner steel sump. Order a couple of spares as well while you are at it. I would also use some sort of washer.