shudder at idle post rebuild.

[love ke70]

hey guys, i rebuilt my sisters 323 astina 1.8 twincam a few months ago as she decided to top it up with 4 litres of oil and fucked the rings and most seals in the motor in a major way.
so the rebuild all went well and the motor has been singing happily ever since.
the only issue, which is starting to annoy me as it hasnt cured itself is that ever since the rebuild at idle its been like sitting in a diesel cab. very shuddery vibration at idle. clears by about 1000-1100 rpm. but sitting at idle your eyes get bounced around in your head.

no idea what may be causing this, so i thought i may ask you guys.

only thing im thinking is maybe the timing belt is too tight, would that be a cause?

im flat for ideas, it couldnt be a vac leak as that would cause the idle to increase.
hmm, anyone?

[slide86]

i dont think the cam belt to tight would cause a huge shudder like that.

engine mount loose? or broken mount?

its not misfiring is it? not lacking power?

[love ke70]

plenty of power
the hydraulic or whatever the hell it is engine mount was replaced and the rest seemed good.
can double check but im sure they are tight.
not misfiring either.
cant compression test the bastard though because the plugs are so deep down

[BeRad]

if the cam belt tensioner works anything like all ive seen it shouldnt be to tight....

throw the old screw driver to your ear and get a better idea of where its coming from.

crank pulley rooted? i changed my mates on his lancer which had the same problem was fine when not idleing as soon as it would idle it was terrible, but you could see that the pulley had problems.

[slide86]

yeah thats a good one^^^. if the balancer is no good then that will cause a vibration.

[love ke70]

ill look into the balancer, cheers
its more a whole car/motor shudder rather than coming from somewhere.
very hard to explain.
its a spring loaded tensioner, but it depends whether someone lent on it with a lever of some type to make sure it was tight. not sure if i did with this car. i know i was in the habit after slipping a timing belt on my 1g twice.
i may just release the tensioner bolt and re tighten it. cant hurt...
so you reckon just have a look at the balancer with the motor running? and that should show whether its farked or not yeah?

[BeRad]

yer, when i looked at my mates you could see it wasnt spinning perfect the way it should it had a slight wobble to it, put a dot on the timing mark or something and youll be able to see if its wobbling about.

haha this seems silly but is the idle to low or something drawing way to much voltage dragging the idle down? and causing a shudder in return? like idle up motor not working?

[love ke70]

its idling around 750-850
the shudder is worse with the aircon off but still definitively present.
might have to check in the book see the specs, and also check charging voltage.
cant wait for this weekend :rolls:

keep any ideas coming, id rather get it sorted than just waste my time. so ill check anything lol

[merc-blue]

could it just need a tune?
My grandmas AE82 seca used to be SOOO bad

[too_quick]

its idling around 750-850
the shudder is worse with the aircon off but still definitively present.
might have to check in the book see the specs, and also check charging voltage.
cant wait for this weekend :rolls:

keep any ideas coming, id rather get it sorted than just waste my time. so ill check anything lol

With the air con on could that be acting as balance shaft sorta thing and when you flick it off the load on the engine is gone so it shakes around. Like if you remove the balance shaft in a commo 3.8, they shake around violently at idle but when they rev up they are smooth.

Sound like a balancing issue somewhere to me ?

[BeRad]

ohh well, youll then know how to stop a 323's engine from shuddering

[wa5]

Do these engines have a balance shaft which might have been mistaken for just an oil pump and not timed up?

[love ke70]

pretty sure there was no balance shaft. its a straight 4...


and sorry i meant the shudder is worse with the aircon on.

and how much tuning might one do on a 95 efi car? its got all new engine electrics

[too_quick]

Straight 4's still can use a balance shaft, Look at 2.6 astron motors.

Massive power drain somewhere or the alternator not liking low revs ?

Just throwing idea's

[love ke70]

it doesnt have a balance shaft mmk
when i see the car, like i said i will check volts etc