Blown Engine

[SniperGT]

First off, let me clear one thing. I didn't blow my lil 4A-C, yet. I would like to know how it happens, and does high revving cause it, and parts of the engine get "blown" or damaged.

Thanks

[Mux213]

Hey Sniper,

There a dozens of reasons why and engine gets blown up. I'm not expert in this but I'll see if I can make some sence.

Revs you just mentioned already, the higher the revs, the more strain on parts, when they exceed the parts maximum, they break.

When you supercharge/turbocharge the strain becomes even higher because of the added pressure in the combustion chamber.
Related to this is a problem that with higher pressure lower octain fuels have their ignition temparature lowered causing the fuel to ignite prematurely. If this happens to soon the mixture will ignite while the piston is still traveling upwards and there are loads of things that can go wrong at that point.

Another that I have heard off but I dont think directly applies to the 4AC because of their head design, but I've seen this destroy a DeLorean engine are the valve springs. If you start tuning your car with other camshafts and stuff it could be that the valve springs you have are not strong enough to push the valves backup in time when they close. This increases the risk of the piston hitting the valve and when that puppy breaks, You'll have an engine full of holes

Oil can be an issue. Leave dirty oil to long in your engine of use the wrong type of oil (to thin in summer or to thick in winter, not change your oil often enough, etc.) and bearings start to wear out, at some point this could seize the engine. Also remember that dirty oil can clogg up oil passages and cause localized oil starvation. These are the worse because you could fix whatever is damaged, and after a few months, have another broken engine. So always figure out the cause, not just fix the results..

Heat can also be a cause for blowing your engine. If your engine no longer gets cooled enough because of tuning or because of the weather overheating an engine will cause things to expand beyond their limits. Usually gaskets and stuff get the most to suffer and will break. Another thing is the oil, oil in an overheated car can become bad, so change that oil!

Last but not least is corrosion. Coolent flows through your engine block and if you dont use the right stuff the coolent passages will start to corrode you engine. This corrosion weakens your engine block up to a point where it simply cracks under strain. On RX7s this can be a weakpoint because some passages run very close to the combustion chamber and when these break, coolent in your engine and one iron to throw away...

[SniperGT]

Wow, great info. I was just wondering because I was thinkng of getting those high performance valve springs and cams for my 4AC and was curious if those upgrades could make it easier for me to blow up my engine.

Thanks for the help

[Mux213]

Hey Sniper,

Not sure about that one I'd say it shouldn't be a problem.

[Knudsen]

If you dont want to risk the life of your engine, dont tune it... Its as simple as that :wink:

[Mux213]

Knudsen, well they can take a little bit of tuning