Lessons learnt about High tuned engines.

[maurici]

Well. So here we are with some lessons learnt after blowing my engine in Cadwell park 5 months ago.

 

Reason of destruction: Combustion chamber numb 1 temperature Too high. Valve stem melted and dropped in.

 

Damage done:

Cylinder number one walls damaged.

Piston number one damaged.

Head fully destroyed.

 

Rebuilt done:

New head.

Honing in cylinder number one.

New piston number one.

New set of rings for piston number one.

 

Worth mention that the perished head, was an SBD head, with a nice and professional porting job and flat top posh valves. The new one, has been done by a Cheshire Genius called Ash Mason (@Arm) who applied all his knowledge to do something even better for a fraction of the cost (and the work) done to the old head, but putting all the attention to the detail than to doing huge and fancy things like porting and polishing.

Things we have learnt.

-Monitoring the Exhaust gas temperature to each cylinder by placing small sensors in the gas flow, is well worth.  Injector number one was half stuck, (30% les flow) and was causing the cylinder going way too lean. Therefore hotter, and this killed my engine.

When rebuilding an engine, worth checking all the ancillaries. Engine Had a major rebuilt and full mapping 2 hours before the blew… we checked all the mechanical components, but we didn’t checked the Injectors. Shame. For the sake of £30 for the set to have them pattern and flow check in a professional place... Definitely is something I’m going to do periodically.

 

 

Go away from the Big Brands.

Bottom end has been sorted using the next street machining shop, and expending a whole day with @AdamR cleaning an re-assembling everything. (Cheers mate)

£3k head, destroyed. A new replacement one for a fraction of the cost. Here is the result. Same end power, More torque in mid-range. My Advice… find your experienced garage engine builder, and walk away from huge companies unless the part you are looking for is not available elsewhere (cams, specific design pistons…), but after seeing that (see bottom plot -Red new engine, black old engine) I can assure that I’m never going to order a branded engine… unless I’m rich, so would buy a Millington because they sound nice.

 

 

I would never had expected that a dodgy injector could Blew an engine. I was really lucky that the valve dropped with the clutch pressed, and in mid-range RPM, (after a very hard acceleration), so the rod didn’t bent, I could save the cams, and the block. I’ve waked away with about two grand, but the bill would have been greater (up to 6-7k) if I had to replace the whole engine… so… yes guys. As we know, going lean is critical and is well known by everybody… but sometimes is really difficult to detect if the injector is only half failing, and the car is still running fine. It wasn’t spotted in the mapping session, but seeing the results back to back right now, we can recall something not working properly, as now the map had required less fuel than the previous one.

 

This tread is meant to be just “my thinking loud” for a newcomer like me in the High tuned engines, and don’t think in them as your daily one. For sure a dodgy injector  like this in a road engine, would had never blew it.

[Kit Car Electronics]

Thanks Maurici, glad you're sorted at less expense than might have been... Actually even a normal road engine can also be destroyed in a similar way, they are relatively highly tuned (albeit typically with more balance to emissions and fuel economy)