2t engine vibrations above 6000rpm

[Pattey21]

Gday all, i have got a healthy 2t in my 73 ta22 which is getting some engine vibrations above 6000 rpm. This vibration is amplified when actually driving.

From standing in the engine bay reving difficult to identify.

Mods include. Stage 2 3/4 race cam, duration 276in 274ex, double valve springs, tuned length extractors with a 2 and a quarter in exhaust, twin dhla 40mm dellortos, head mild and match ported, and shaved 40thou. Big radiator with lower temp thermostat no mech fan.

Car doesnt miss or anything at this rpm and should be good till 7200 before begining to run out of breath.

Took it to the guys at Auto Tech services hume and they dont know either.

Any ideas? All input greatly appreciated!

[Pattey21]

Also the t50 is in good condition bushes also. Does have a slight diff play at thats it. Thanks again

[thechuckster]

flywheel OK?

(fwiw: Takai had the Fidanza flywheel on his 4age do some funky things in roughly the order of: clamping face for flywheel bolts didn't perform as expected, several bolts loosened and backed out, the engine got some high revs and the flywheel then decapitated the remaining bolts thus munting the crank and flywheel.)

[Pattey21]

Dunno never checked? Guess there is no easyway without removing the gbox. Thanks for the response

[Shakotan_Aaron]

does it seem down on power at all?

could be breaking down in spark at higher revs? not a full miss but not a full combustion.

also pressure plates are normally balanced with a spot weld of steel onto it, possible it may have come off.

how extreme vibrations is it?

[Pattey21]

Gday,

No noticeable power loss good idea with spark, howerer i am running a accel super coil with top gun 8.8mm leads so dunno if that would be the issue.

Could be pressure plate too but wouldn know without detaching gearbox.

To gauge vibration non-technically, when it gets to that rpm, it sounds more like its coming from the engine but can still feel it through the gearbox not much though. It does not vibrate in a way that makes me think "its going to blow" or something is broken, but more so that something needs tidying up.

vibration like dumping an exhaust from the headers and its right under your seat sort of vibration but not with the same decibels.

Engine sound does also change when it begins to vibrate sounds like its going hard but not runnning out of breath or dieing.

I hope thats helps to diagnose.

[Shakotan_Aaron]

but your sure this is actually a problem?

is this a 2tc or 2tg?

if a 2tc, these motors are not really that rev happy, ive driven a few 3tc cars (granted they are longer stroke) but they where never rev monsters. im not sure if either had a fully counter balanced crank, and im not sure that it may make any difference.

its definitely normal so have some vibrations esp with a 4cyl engine.

the sound from a tuned revving N/a motor vibrates my internal organs and causes me to become high.

[stocker]

My Cortina used to do this though I never figured it out. I was told be a couple of people the engine is old and on it's way out though it kept going fine except in the higher rev range. I ended up selling ti this way so didn't resolve the problem.

[Rodger]

Anything could be resonating at those revs, apart from the noticable change in induction sound coming on when the cam comes in, and this would be a very mild change for that cam probably at around 3500 and dependant on the Dellorto tune.

I suggest feeling things such as throttle linkage or brackets, holding pipes or checking for loose bolts or nuts or brackets and try to hear a similar pitch of sound when tapped.

A loose exaust bracket can resonate easily.

Check the rocker assembly and your valve clearances. Also possible that some of the rocker retainer springs are weak allowing the rockers to float sideways on and off the valves more readily than normal, but this would effect power.

Sometimes the gearbox/engine block mounting plate can vibrate violently if one or two of the lower stiffener brackets are not fitted or a bolt is left out.

The water pump may have a worn bearing allowing it to rattle. Try to rock it side ways to check for play.

The OEM baffle plate in the sump may have broken some spot welds and is resonating.

It could also come down to simple air resonance in the induction and this is the sound it will always make. Try removing the air filtering system you are running.

Come over one evening and we can try sort it out together. Or I can say that it is what it is.

Regards

Rodger

[Pattey21]

Hey thanks a lot for your opinions. Was testing it the other day and in second it would not rev out past 6800 no mech noise or anything just would not go past. that turned out to be points. First will rev out no dramas, 2nd after 7000 starts to slow down but i think thats just the cam running out of puff/tuning.

The noise is still there but again could be a number of things.

Tightened all gbox mounts engine mount, water pump should be okay.Rodger do you have a mobile number pm if so if not ill give you a call during the week.

cheers
pat

["Z" UTE]

Hey thanks a lot for your opinions. Was testing it the other day and in second it would not rev out past 6800 no mech noise or anything just would not go past. that turned out to be points.

cheers
pat

Ditch the points ignition setup. Roger can clue you in on how to elimate the bludgers.


cheers Chuck