A couple of idle and ticking questions

[ber55ber55]

So i did a valve adjustment and did the gasket and rocker plugs all at the same time....

Ive been driving the car a couple days and have been noticing some strange things.

1) the engine "ticks" pretty loud under light thottle. It ticked before i did tthe vlave adjustment, but i just want to make sure this is normal for m20's. It not overly loud but the engine does tick tick tick tick tick pretty good.

2) The idle is slightly ackward. When the car is cold, the idle is around 400 and is extremly ruff, but once the car reaches normal temp, the idle stabilizes around 800-900rpms. Whats extremly wierd that i didnt have before is that the idle slightly oscillated now between 800-850, but just ever so slightly. My question being...am i just being picky? or do i have a vaccum leak again?

3) lastly when i have the hood up and im playing with the throttle and hold it at a good 1500-2000 rpms the engine sounds like it is slightly misfireing or the timings off. But its also very slgiht. Again, am i being picky?

I have now almost 140k the car. I recently replaced the centering bearing, guibo, pilot bearing, release bearing, pressure plate, clutch, all tranny seals, flushed tranny, tightened linkage, replaced oil pan gasket, and rear engine seal. Could any of this have caused a problem?

Thanks in advance for any insight:D

[Bin_jammin]

So i did a valve adjustment and did the gasket and rocker plugs all at the same time....

Ive been driving the car a couple days and have been noticing some strange things.

1) the engine "ticks" pretty loud under light thottle. It ticked before i did tthe vlave adjustment, but i just want to make sure this is normal for m20's. It not overly loud but the engine does tick tick tick tick tick pretty good.

2) The idle is slightly ackward. When the car is cold, the idle is around 400 and is extremly ruff, but once the car reaches normal temp, the idle stabilizes around 800-900rpms. Whats extremly wierd that i didnt have before is that the idle slightly oscillated now between 800-850, but just ever so slightly. My question being...am i just being picky? or do i have a vaccum leak again?

3) lastly when i have the hood up and im playing with the throttle and hold it at a good 1500-2000 rpms the engine sounds like it is slightly misfireing or the timings off. But its also very slgiht. Again, am i being picky?

I have now almost 140k the car. I recently replaced the centering bearing, guibo, pilot bearing, release bearing, pressure plate, clutch, all tranny seals, flushed tranny, tightened linkage, replaced oil pan gasket, and rear engine seal. Could any of this have caused a problem?

Thanks in advance for any insight:D


The tick sound is probably lifters. They may be worn out ( I don't know if you can shim m20 lifters) or they may be gummed up pretty badly. You may want to consider running a slightly thinner grade of oil.

So far as your idle, I'd check out your coolant temp sensor and all your vacuum hoses, just to be safe.

The misfire sound? Might be a misfire, when was the last time you did a cap and rotor? Check the resistance on all your plug wires to see if you've got a bad one. Spark plugs new? Give up some more info for some further advice.

[ber55ber55]

What are lifter? When I did the valve adjustment everything seemed pretty clean and ungummed.

Yes with the sensors.....they look pretty worn and sometimes there is coolent residue around it. What is the normal resistance on these? Vacuum leak, the only leak i can figure there being is the cover on the back of the intake manifold. The gasket, when i took it off to do the valve adjustment, it looked pretty jacked up, but i didnt have a new one, and i doubted it wouldnt reseal, but maybe that is the problem.

Plugs, i replaced them about 500 miles ago. They were bosch plat. +2

[Bin_jammin]

I don't know what the resistance is supposed to be on your sensors, and I've got an m30, you're going to have to poke around to find that.

[attack eagle]

The tick sound is probably lifters. They may be worn out ( I don't know if you can shim m20 lifters) or they may be gummed up pretty badly. You may want to consider running a slightly thinner grade of oil.

Give up some more info for some further advice.

Funny thing. I decided to go from 10w40 to 10w30 on my m50, and itstarted ticking like like the White Rabbit's watch... Did a little old school trick to flush any deposits or accumulated high mileage crud (+1 qt ATF in the crankcase) and changed the oil to 20w50 (104 degrees in the shade here last 2 weeks) and no ticking any more.

Possibbly doesn't apply to m20s because ofthe different lifters design... but if you recently changed oil to a lighter weight, you might consider changing back.

[ber55ber55]

alright ill try to find the resistance somewhere in the forum...

but what are lifters?

and no, i havint changed oil recently to a different grade, but i WAS thinking about using one of those oil flush additives. Thanks for the help and advice.

Alex

[jiminEcricket]

the m20 motor does not have lifters. there are shaft mounted rocker arms that connect the valves to the camshaft lobes

[bsell]

but what are lifters?

Alex

Lifters are used to transmit the motion of the camshaft lobes to either rocker arms or pushrods, then rocker arms. The lifters can be either solid (mechanical adjustment on the rocker arm) or hydraulic (auto adjusting until thier very tiny oil passages get gummed up, then they tick also!).

If the camshaft lobe directly actuates the valve the things in between the cam and valves are 'cam followers'.

But your engine has rocker arms that ride on the camshaft lobes which is yet a different system than the other ones.

On to your problem...

You say the 'normal' valve tick is louder than before. Are you saying they are all uniformly loud now? The reason I ask is if you have a 'tight' valve (one that doesn't really seat firmly) you can get a rough, low idle and missfire at speed. What is happening is the combustion pressure is blowing past the softly-seated valve in almost blow-torch fashion. If you are thinking this is a bad thing, you are right!:D This is a common reason valves 'burn'.

The other reason a valve burns is it doesn't spin in the guide. When a valve is operating properly, it should slowly spin in relation to it's seat during every open/close cycle to help clean off any garbage on the valve seat, preventing leakage and burning.

So if you have a very smooth, sewing machine-like sound from your valve train; they should be nice and evenly loose. Overly loose valves get slapped around during uncontrolled crashing onto their seats. Yes, this is also a bad thing over the long haul as it causes excessive seat, rocker arm, and valve wear.

If the ticking is not smooth or has a 'beat' to it, you got a tight valve or two (or just a less loose one) than the rest.

As your problems began after the valve adjustment, this might mean another trip in there to ensure the valves are set properly. Or you could have a vacuum line loose causing a lean start/cold run making the idle speed low. Once the engine is warm, it will tolerate a lean mixture better, causing the higher idle than when warm.

Brian

[ber55ber55]

well the thing is, that is only does it under load. I have heard it could be a header or something of that sort.

When the car is sitting and i play with the throttle i have NO sound other then the engine cranking up

But when I am moving and i hit the accelerationg and am above 2k rpms, i get a ticking sound.

I have also heard this could be a temp sensor which is causing a bad mix.

The idle is OKAY. Just slight oscilation i.e >50 rpms movement

The only other thing is the extremly rough idle when cold. But i am assuming that is normal.

At this point I am almost conviced the ticking is a normal sound. I have checked the valves again, and everything is cool. I am going to replace all the different sensors next, just for the hell of it, since they havint been replaced.

Alex

[ber55ber55]

I also dont have misfires, or rough low idle. And honeslty, i think i am imagining that its louder now. I think its me just trying to perfect my machine

[ber55ber55]

Oh, that is misfires while driving, but when the car is idleing, it sounds like the timing is "slightly" off. It was the same before the vale adjustment

[E34-520iSE]

My M20 engine never misfires from a cold start, since I reworked & fitted my spare cylinder head. It starts from cold on a morning in only a few cranks (about 1/2 a sec) and idles at approx 1200 rpm until it warms up, then the idle drops to a constant 850 rpm. Any misfires or 'using the throttle' to start the car is just wrong. You will hear a small amount of valvetrain tick as well as the fuel injectors ticking, this is normal. M20's are an old design of engine, but they should still run perfectly well if correctly adjusted.

HTH,

Shaun M