Just done a Compression test and im not happy.

Been driving my car today and as i was driving i thought its starting to sound more and more like a fiesta CVH engine, for those that have never heard 1 they are very tappy top end.

So i came home popped the bonnet and listend better, when on tickover its sweet but once i hit 3 thou revs its really tappy.

So i called my engine builders and they told me right away ive bent some valves, so i said how can you tell and they just said to a comp test and you will see.

I found my tester out took all the plugs out and found these results

cyl 1 - 120

cyl 2 - 170

cyl 3 - 170

cyl 4 - 170

cyl 5 - 120

cyl 6 - 170

Now the firing order i think is 1 - 5 - 2 - 4 - 3 - 6, or somthing like that 1 - 5 for sure, so how can i have bent valves, they say its been over revved and they are prop right lol.

But i just cant see them bending unless they have hit somthing.

Feel sorry for you mate :/

This is not good :/

Ah mate sorry to hear this

I thought you could only bend valves if the cambelt broke...

Although would it be possible to bend the valve if it was over reved??

Piston coming back up before the Valve spring had the chance to retract the valve?

like richard said, i thought the only way was if the cambelt snapped. making the pistons get to know the valves abit better. hope you sort it out mate

Is it possible too bend valves with high compression? Sure I've heard that when I had my Rst, bad luck fella hopefully it's a cheaper fix then a head rebuild

I thought the supra was non interferrance?

Yep the 2JZ is non interference,, can you do a leak-down test, that will enable you to tell if its ring/bore seal related or valve/seat seal related.

Num is running a 1jz.

its a 1jz isnt it lads?

1JZ's are non interference too aren't they? or at least they are pre VVTI, thats what I was always told about my MK3.

sorry to hear about that mate! and you just got your single turbo going !

Not good mate:rolleyes: if you need a hand................................i`m busy.

Why do they think it's the valves?

not good mate:rolleyes: If you need a hand................................i`m busy.

Not good mate:rolleyes: if you need a hand................................i`m busy.

Burn

Sucks man, hope you manage to fix it easily!

Could it be a valve spring broken?, you did replace them on the build didn`t you?

Think its valves as 1 - 5 are the same firing and its very tappy top end, not if you just rev it but hold it at say 3 - 4 rpm and its noisy.

Car starts and drives mint with no hesitation or missfire or lumpy.

Im going to take the rockers off tomorrow and check the clearance's and if they seem out then ill take cams out and check the valve springs.

My other thought is i have adjustable cams but as all the lobes are all the same hight if they was adjusted wrong then all the pistons would be out.

I also might adjust the cams back to stock setting and do another test.

If it is the valves it wont cost me nothing as i have a spare engine down the garage and my engine builders will do it for nothing as they love me lol, ok they will help me fix it lol.

When over reving the engine the valves will float. And if the engine is interference the valves will be bent most likely the exhaust valves as the piston chase the valve.

Valve float can also make the valvekeepers to jump out from the retainers and the valv would drop into the cylinder.

If you have acsess to a leakdown tester you could test and see of you get any noise in the exhaust port/turbo to determind if its the valves or somthing else

When over reving the engine the valves will float. And if the engine is interference the valves will be bent most likely the exhaust valves as the piston chase the valve.

 

Valve float can also make the valvekeepers to jump out from the retainers and the valv would drop into the cylinder.

 

If you have acsess to a leakdown tester you could test and see of you get any noise in the exhaust port/turbo to determind if its the valves or somthing else

This makes sence and especially as it has cam timing adjusted, might have made it interference BUT i will take the head off if the shims dont measure up right.

i dont know if the 1jz is interference or not its either interference or non interference, changing the cam gears wont affect it. however if it is an interference engine using adjusteble camgears is more risky if the bolts that holds the adjusters slip it could cause the piston to slap the exhaust valve.

good luck tho mate!

The 1JZ is definitively a NON interference engine. There is no way for the valves to physically hit the pistons, even if you wedged every one wide open and spun the thing over. Cam timing, adjustable cam gears, snapped belt etc, it's impossible for them to touch. It's possible that you've burnt the valve seats out though, running lean on them cylinders?

I'm unsure of the firing order, but could be a faulty injector driver if running batch fire on them two cylinders? What ECU are you running?

possibly contaminants on the seats....carbon build up will cause ticking sounds, being so hard.

Whip the plugs out, take a photo of the colour of them, I'd say it's ran lean on the two pots.

All 6 plugs are identical in colour and my AFR gauge always reads good, but like you said that dont mean to say them two cylinders havent run lean.

Im taking the head off anyways as i want my car to be perfect.

The 1JZ is definitively a NON interference engine. There is no way for the valves to physically hit the pistons, even if you wedged every one wide open and spun the thing over. Cam timing, adjustable cam gears, snapped belt etc, it's impossible for them to touch. It's possible that you've burnt the valve seats out though, running lean on them cylinders?

 

I'm unsure of the firing order, but could be a faulty injector driver if running batch fire on them two cylinders? What ECU are you running?

Even with higher lift cams, as per the 2JZ (in general, not just in this case)?