Does anybody have any experience with an Uno Turbo braking a conrod? What was the reason?

ECL said:

Does anybody have any experience with an Uno Turbo braking a conrod? What was the reason?

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what sort of boost/mods were/are you running

I am looking at 2+ bar boost and 1.5 bar with NOS. BB GT2860R turbo. Mods on the block, peen shot conrods, balancing all relevant parts, lightened flywheel, bigger intercooler and oil cooler, Weiseco pistons, gasflowed head with head stud kit, custom cam, EFI with 550cc injectors and 76mm exhaust.

My concern is that with all the time and money spend I would put a conrod through the block and mess it all up with 2 high boost. Maybe there is somebody with experience that would help me out.

Well, I have plenty of experience with NOT breaking con-rods on FIAT engines

I believe a main cause of this problem would be excessive bearing clearance/crankpins worn oval. With the amount of effort going into rebuilding that engine, it shouldn't be too much to measure the crankpins carefully in two directions and ensure that replacement bearing shells are the correct size, fitted in conditions of absolute cleanliness.

My pretty-much standard Uno Turbo engine develops peak power at somewhere less than 6000RPM. It's easy with a turbocharged engine to run well past peak power. I'd suggest an observed rev limit of 8000RPM unless you have had all the rotating parts balanced. Note that as standard, FIAT engines are well-balanced, so you have to be certain that your 'expert' balancer is not likely to make things worse!

Just my thoughts. You really have little to fear; blowing the head gasket is a far more likely possibility at those boost levels.

-Alex

This is what could possibily make it throw a rod:

Detination (Like how a diesel engine works, compression ignition)
pre-ignition (a hot spark plug electrode, coke build up, incorrect ignition timing, these factors will ignite the fuel before the spark plug does)

Caused by

1) Ignition timing and the octane of the fuel that is used
2) Cokeing up of the combustion chamber (Hot spots, valve not seating properly, etc, etc)

The piston could be coming up on the compression stroke and the air/fuel mixutre is ignited before the spark plug ignites and that will put MASSIVE forces on the connecting rods but the big-end shells SHOULD take the force as they will "crush" under the stress but pro-longed detenation or pre-ignition will kill a rod(s)

Any clearnces will promote a knocking sound a the engine should be used at all if there is any knocking sounds

Never heard of a broken UT rod. However use the 1300 rods, not 1400. 1300 are forged, 1400 are generally cast.

I unfortunately dont have access to 1300 conrods. There are very few 1300 in SA.

Thanks for all the advice guys. I feel much better knowing that the sub assembly is fine.

1500 rods are the same as 1300T

Is that the X19 conrods?

yes