Technical Timing belt help

[jidebl]

Good day, everyone. I have an old Fiat Ducato (1996–1998) with a Sofim 8140.43 engine. The original timing belt has 154 teeth, which is very rare in Nigeria, and even online it’s not shipped here.

My mechanic replaced it with a 153-tooth belt, which is more common locally. I’ve been using the vehicle for almost a month with no issues, but I’m concerned about its longevity. I don’t know how he managed it, and he didn’t explain, knowing I’m also a mechanic. Can this setup last safely?

 

[Mike1alike]

If it is long enough it can.
How tensioned is it? If it's too tight is very bad, with possible damage. It will brake and there'll be bent valves, contact between pistons and valves. If it's long enough and sits proper tensioned, it's ok.

 

[lancepar]

Are you sure this is the Engine crank/valve Timing Belt you are asking about? I don't think it is.

 

[Communicator]

Are you sure this is the Engine crank/valve Timing Belt you are asking about? I don't think it is.

Why not??? A little research will show that 152, 153, and 154 toothed belts are used on the Sofim 8140 series engines.

 

[Communicator]

Good day, everyone. I have an old Fiat Ducato (1996–1998) with a Sofim 8140.43 engine. The original timing belt has 154 teeth, which is very rare in Nigeria, and even online it’s not shipped here.

My mechanic replaced it with a 153-tooth belt, which is more common locally. I’ve been using the vehicle for almost a month with no issues, but I’m concerned about its longevity. I don’t know how he managed it, and he didn’t explain, knowing I’m also a mechanic. Can this setup last safely?

As previously stated 152,153, and 154 toothed belts have been used on Sofim 8140 series engines. These belts seem to have a 0.375 inch pitch, which is approximately 9.5mm. As the wrap on the tension roller is considerably less than 180deg, the roller would have to be pushed back by considerably more than 1/2 of the belt pitch, compressing the tension spring further with the shorter belt.

A search on Ebay reveals an offer of a 153 toothed belt for a 2.8D engine presumably the 8140.63. This offer is from Coastal Motorhomes, who are frequently recommended on this forum. In a footnote they include the information that both rollers are 67mm diameter. My 2.8jtd (8140.43s) uses 64mm and 67mm rollers. I am wondering whether the use of two 64mm rollers could have eased the installation of the shorter belt, and reduced final belt tension?