Possibly Bent Valves?

[DeFl0wEr3d]

My car was running in 3rd gear going 120, and instead of shifting to 4th gear, i accidently shifted down to 2nd gear. The car was struggling to drive after that, i was pushing the accelerator and the revs were dropping.

Took it to the mechanics and he said he did a compression test, in cylinder 1 and 4 has 25% while the others both had 175%-200%.

He said it could be the timing belt from a couple of teeth missing, so he checked that out and he said it wasen't aligned and a few teeth are missing. Replacing the timing belt could be the fix.

Not sure i want to waste $400 for him to tell me the valves are bent.
Can i get you opinions guys, would really save time, if it sounds like bent valves thats a$2000 job, probably better off selling it.

[trism]

Its not measured in % its measured in psi.

If it has bent valves, you wont be able to get anything at all when you sell it.

It is an interference engine from memory, so it would only have a bent valve if the timing belt broke.

Over revving an engine, could be one of many things. Valve springs, stretched conrods, bent rods, its an engine apart job.

Sent from my Xoom

[xclusive_eg8]

That's basically over revving the engine, the head was probs taken way way past Rev limiter. Is there any ticking/clunking comming from engine?? What's it feel like to drive?? You could have chipped a piston all the way to floated a valve. Explain what is now happening.

[DeFl0wEr3d]

Yeah it over reved by alot way past the red part on the revs. No ticking or clunking coming from the engine. When the cars cold , its runs pretty well , but it sounds like its running on 3 cylinders. By the time it warms up the car will drop up and down in revs for a couple of seconds and then stall.

[dougie_504]

If your compression test was 25PSI in one cylinder and 175-200 in the other three then it sounds like you're in a bit of crap dude. As trism said, it'll be a tear-down job.

Otherwise if you can determine if it's the head or the block I'd be tempted to just swap it out, or just put in another longblock altogether...

[PtR_008]

get a leak down test done. it should help determine what has failed and needs replacing.

[Nepolian]

get a leak down test done. it should help determine what has failed and needs replacing.

Compression generally tells you there a leak in piston. Leak down will tell you if it is valves! I say take it to a better mechanic that know how to diagnose simple mechanical faults!

[bennjamin]

Avoid wasting time and money mate with all these diagnosing
You have ****ed your engine - it needs pulling apart at a minimum so get some cash get a quote on a rebuild and compare this to say a 2nd hand engine

What's your location ?

[DeFl0wEr3d]

Yeah a rebuild is what its going to come down to, im in sydney near parramatta area.

[h2cker2]

what ended up happing with this?

[EVLGTR]

out of curiosity, do you shift as if your backhanded? my friend does it all the time and often misses 4th completely coz it applies more pressure to the left.

[munkaii]

I don't know why people would go 3-4 with a backhand grip. The only time you should use that type of grip is 1st-2nd or 3rd-2nd or 5th-4th, but never 3-4 for the very reason above.

[dougie_504]

^

Fair enough if you're a crap driver, but to be honest I think most competent drivers could shift from any gear to whatever gear they like with a backhand grip, but then of course most of us would know to just do what's smartest IE the correct grip and shift to the correct gear.

[munkaii]

Indeed, if I was taking a sweeping left and I couldn't reach the gearstick using a normal forehand grip, I'd use a backhand grip. It's a straight down movement so I don't get why it can be difficult o.0