Problems when accelerating hard

[damian666]

I think I mentioned this before, with the 90mph crackle thread.

However, I have noticed that its happening in all the gears at the top of the rev range. When caning it through the gears, it stutters really badly - this is mostly noticeable when changing between second/third gear, wit the throttle wide open.

I've replaced the rotor arm, cap, plug leads, air filter, oil. Its a 1.2 carbed.

Any ideas?

Thanks
Damian

[Aragorn]

changing gear with the throttle open?

thats a surefire way to shagging the engine

valve bounce most likely - im surprized youve not snapped any rockers

[damian666]

I don't know a lot about engines, but I do know that there are no rockers in a 1.2 nova. Its OHC and has hydraulic lifters.

anyway
My description above was a bit shit. I meant that I'm ragging it through the gears - obviously I'm lifting off when I push the clutch pedal.

Still, it was doing it again today - bogging down in third, after a hard accelerate between first and second.

Damo

[Stuart]

swings and roundabouts on the descripton of the cam followers.

they look like "lifters" like you get in ohv engines, so its easy to just call them that :)

umm get the carb tuned and make sure that your timing is spot on.

appart from that, drive like a "sensible" human being and let off the throttle when you shift.

[BIGH]

Just a thought but have you had your water pump checked coz mine did the same thing then the water pump collapsed n bent a valve.
it may not be but it wud be worth gettin it checked

[Jack]

bit of a long shot, but what's the outside temperature like when this happens? My 1.2 sometimes loses top end when accelerating hard in cold weather, like the carb iced up.

[Nath]

that sort of problem happens with mine where it stutters. does it do it when u change from first to second? mine does and its because the distributor is knackered. its ok changing the rotor arm and cap but they dont do much its the distributor u need to check.

[mowgli]

the advance / retard diaphragm is probably tatered. to test this, start the engine, pull the small nylon pipe (from the dizzy to the carb) off at the carb end, and suck on it. if the engine note changes, then it is ok. if not, then get one ordered.

[Mel]

that sort of problem happens with mine where it stutters. does it do it when u change from first to second? mine does and its because the distributor is knackered. its ok changing the rotor arm and cap but they dont do much its the distributor u need to check.

thats exactly whats wrong with mine..the dizzy's buggered..always stutters but usually stalls :(

[Aragorn]

an OHC engine has rocker arms (aka cam followers) and hydraulic lifters (aka tappets although not strictly the same as a tappet)

at high rpms the rockers tend to give out first

its a safety mechanism of sorts - make the rockers the weak point and u save the valves/head/pistons

doesnt always work that way however

[Ste_Nova]

yeh sometimes it goes wrong... my 1.4sr was reved to 8000rpm... snaped rocker... shagged engine

used to pull indicated 130 on the flat... has never been the same since.. even after 2 rebuilds, lots of mods and 6 years :o