Engine Kaboommmm... A question to answer...

[chris2000]

my assupmtion only k, don't flame me.. hehe..

Honda block and head are aluminium hence they get warped easily if overheat. So very common for honda block and head to skim. So if they skim too much, the valve to piston clearance is very tight.

Furthermore, the pre-tensioner bearing on Honda has to be set and tighten properly and really tight to prevent them from slipping at high rev. The design of the pre-tensioner are very different from Proton so thats why they have to be tighten properly.

So assumming the mech did not tighten properly or set it too loose, as you run the car over time or at higher rev, the pre-tensioner can't hold the timing belt load and slips a tooth or two. And when this happen, your valve to piston being closer and tighter(due to skimming), that one or two tooth misalignment is good enough for the vavle to hit the valve pockets of piston. When this happen it could have broke the valve and the valve fall onto the piston. Then on the next up stroke, the stem of the valve will get crush through your piston causing the hole in the center of the piston (quench area) and the flat side of piston hit the head!

My assumption and imagination from my experience seeing many engine blow.

Hope this info will help.. :)

 

[hattech-v]

hehe.. no one going to flame anyone... sharing is caring.. haha
one more thing, is it possible if the afr running too lean will cause that kind of damage?

 

[shiroitenshi]

oh chris, yes the owner did sent the block n head for the skimming but not sure how much it being skimmed...

Wah... skimmed ah? I thought standard only... (>.
The people doing skimming in Malaysia can make the deck really really level ah? or 99.7% only? hehe...

 

[hattech-v]

is it? never done any skimming job b4... but then where to send for the skimming job to get it 100% accuracy? hehe

 

[shiroitenshi]

is it? never done any skimming job b4... but then where to send for the skimming job to get it 100% accuracy? hehe

Golden Eagle, CA. My friend sent there.. step decking and sleeving.. still not finished after six months.. lol!!
Expensive like hell.. which is why even if I had the money... still think 30x before plonking that kind of money.. half the price of EG oh!!

After that, send back by ship.. 2-4 weeks again.. haha...

I wonder how long they take? My friend isn't rushing them, so I guess those US guys doing it slow.

It's not the first time, so no worries about those guys not sending them back.

 

[eater_eg6]

if too lean... the piston will melt... rite ? n dun think the valve will pecah like that... so i dun think is the afr prob...

 

[shiroitenshi]

if too lean, detonation.. sometimes can break rods.. happened before to one of the people I've met.

However, assuming it's valve clearance, why only one valve is affected?

Installation error maybe?

 

[Enthusiast]

So what if the engine is running too rich? Any terrible side effect?

 

[shiroitenshi]

So what if the engine is running too rich? Any terrible side effect?

Plug fouling, which which will cause a bad case of engine coughing.. hehe..

 

[Enthusiast]

omg....engine coughing as in?? car jerk?? black smoke??

 

[J101]

the head skimming should be okay, u have to have a good reason why they had to mill the block koz its not a good thing to do. its just not a rule of the thumb to mill the block unless its warped badly.

oh chris, yes the owner did sent the block n head for the skimming but not sure how much it being skimmed...

 

[J101]

definitely my friend.

hehe.. no one going to flame anyone... sharing is caring.. haha
one more thing, is it possible if the afr running too lean will cause that kind of damage?

 

[J101]

too rich are as bad as too lean. running too rich will wash down the cylinder walls and you will begin to burn oil and abit of cylinder bore wear. the extra fuel will wash the oil off your cylinders and wear out your pistons, cylinders, and rings quickly (no oil), in addition to building up deposits on your valves, heads, and piston tops.

So what if the engine is running too rich? Any terrible side effect?

 

[hattech-v]

too rich is better than too lean rite?

 

[akuma]

pls update us on d diagnosis.....very confusing ler...n DAMN...MADNESS man!

 

[TODA]

sry, offtopic, but related....

is a dynotune shop equipped w lamda sensor good enuff to chk our A/F R accurately? I think my engine is running rich

 

[Enthusiast]

i think mine is too......when start car can see some smoke come out.......and it smells of petrol......

 

[hattech-v]

white smoke or black?

 

[shiroitenshi]

sry, offtopic, but related....

is a dynotune shop equipped w lamda sensor good enuff to chk our A/F R accurately? I think my engine is running rich

Don't be confused with AFR.. I used to be. A certain AFR, like .80 in lambda scale may be lean for one engine, and just right for another. So, there isn't an accurate AFR number. It depends on how well your engine flows at different RPMs.

AFR for different engines is different. For example, I had the opportunity to see two B20B with unichip getting tuned. At 3000rpm, both cars have different AFR, although both are built with the same specs (Type R head with B20B block), except for certain things, like different mufflers, different intakes, different plug cables, etc.

There is no 'magic' number for AFR, the only magic number is 1.0 (or something close) when idle.

The right AFR is when it generates the the right horsepower at certain RPM without bogging/overheating the engine. A lot of factors goes into it after that, and it's a bit too lengthy to explain, and there are many gray areas I'm still learning about.

AFR from different places along the exhaust pipes have different readings. That's why you have the 'calibrate' button on most AFR meters (e.g. Innovate's, or Motec, that calibrates on startup)

 

[TODA]

i think mine is too......when start car can see some smoke come out.......and it smells of petrol......

start car as in cold start? if cold start should b normal engine will run richer pumping mre fuel but smoke? sounds serious man, mine's jz the 'pop pop' sound outta my exhaust only but i knw im running rich coz i always see my spark plug having some black carbon ash deposits