Hi Guys

Snapping con rods, is this a normal problem when tuning a Mondeo V6?

The conrod that snapped was the middle rod in the front which I think is
called number 4. This snapped in a 97 car and in an 01 car.
Same flowed heads were on both cars, not skimmed.

BHP is approx 30 up on standard .

Any help or pointers would be gratefully recieved

Cheers Malc

 

Well if it happened twice to you, it sounds like a common problem!

Rods only normally break due to either excessive det or excessive rpm IME, flowing the head(s) on an engine and keeping the same rev limiter is unliklely to cuase a problem.

 

Hi Chip..

I think he has changed the cam shafts, maybe the timing out and its suffering det.... It is a tough one I thought on a N/A engine you would really have to go some to snap a con rod....

Cheers

Malc

 

on a NA engine, rods will almost always break whilst in tension (ie excessive rpm as Chip says, at the top of the exhaust stroke), in fact it's often the bolts that break first, or round the cap..

I've never seen a rod break in compression direction in a NA engine, (maybe with huge boost forced induction/NOS...)

looking at the remains of the rod should give you a clue what happened and where it broke

 

RichM, I agree totally.

The number of arguments ive had with people telling them they dont need to change rod bolts due to adding nitrous etc is silly.

People just dont seem to be able to seperate the cylces out in their mind and realise that rod bolts are typically under less strain if anything not more when used on a nitrous engine! (unless you use nitrous to extend the RPM range of the engine by forcing it to breathe somewhere it couldnt before of course!)

 

Hi Guys

Thks for the responces, What tuning companies would know this engine inside out??

Cheers Malc

 

Up for the day guys please

Cheers Malc

 

Engine was be running a little lean because of bigger throttle body and filter. Would this have any effect?

 

Camshafts were the standard.