4d56 mits experts help please. If everything else is fine with engine but the balance belt timing is set up wrong on an early 19

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roadkillcafe, May 8, 8:32pm
If everything else is fine with engine, but the balance belt timing is set up wrong on an early (1989) non-turbo 4d56 (4 cyl diesel in an imported delica), how badly will it vibrate (i.e a BIT rough, or REALLY rough) at idle (approx 800 rpm) in neutral, and how will vibration change (i.e will it increase or decrease) as revs are gradually increased! (in neutral) Knowledgable info greatly appreciated, thanks in advance.
a.woodrow, May 8, 8:39pm
Vibration at idle, Gets worse at mid revs then at higher revs goes away
roadkillcafe, May 8, 9:23pm
cheers, do you have specific experience of this particular engine in this situation! how bad on scale of 1 to 10 (with 1 being slightly rough and 10 being the engine jumping around quite violently) and at what rpm's would you say for the numbers on scale!
a.woodrow, May 8, 10:08pm
It's pretty irritating, the balance shaft is def there for a reason lol, I couldn't tell you what revs though just going from memory. do you think someone has got the balance shaft out of time!
snoopy221, May 8, 10:55pm
Vibration at idle, Gets worse at mid revs then at higher revs goes away

how bad on scale of 1 to 10 (with 1 being slightly rough and 10 being the engine jumping around quite violently) and at what rpm's would you say for the numbers on scale!

Between 2 and 5 depending on rev range.
Similar vibration to a dead cylnder/misfire-sprk plug lead removed on a petrol. hard to describe really.general rough/harsh feel varying with enginerpm.
roadkillcafe, May 8, 11:13pm
thanks mate-yep same engine, found that centre rocker shaft mounting bolt hadnt been fitted properly and as a result they all loosened/broke, all that is sorted correctly now but it has a EXTREMELY rough idle and it smooths out as revs get beyond about 1100-1200rpm in neutral and i'm looking for the cause. As far as i can establish so far everything else is as should be (cyl head is brand new, ive double checked valve clearances, cam timing etc) id be really surprised if balance timing was out and dont wanna dissasemble it to check balance timing unless i really think that its likely to be responsible. What do you reckon!
roadkillcafe, May 8, 11:26pm
yeah well my experience is on petrol engines and this thing idles just like a 4 cyl petrol but if it had the compression of a diesel and if it had a plug lead off (i.e it's like it's trying to literally leap out of its mounts)
a.woodrow, May 9, 12:01am
Pull the cover off and have a look. Only way you can really rule it out
gizmsme, May 9, 12:03am
Have had a lot to do with mitsi engines includingthe d55 / 56 series, With a mistimed balance shaft I've not known them to vibrate as bad as you suggest, especially at idle.always seems to be above idle.
I'd put my bet on there being another problem!
snoopy221, May 9, 12:53am
id be really surprised if balance timing was out and dont wanna dissasemble it to check balance timing

Well read what i wrote-and set it up on no1 TDC And remove the blanking plug and see if a screwdriver goes in or not.
[Tip-any decent workshop manual should explain-or google is ya friend=one blanking plug undone and check]
Personalyi agree with post# 11- And you don't really specify if it's JUST mainly rough at idle and smooths out at r p m.

I M H O I'd fire a compression tester at it-only takes a leaking valve-poor machining and 3 cyl idle.
roadkillcafe, May 9, 1:07am
that's true
roadkillcafe, May 9, 1:11am
and i have a sneaking suspicion/feeling that you're right-however i think i might go thru the rigmirol of checkin balance timing to at least eliminate that. Cheers mate.
roadkillcafe, May 9, 1:16am
i will check balance timing-im not where the vehicle is at the moment and i will.google it later, but while were at it, is it possible for me to check balance timing conclusively via the hole mentioned without me having to remove crank pulley, lower timing cover etc!
beast9, May 9, 1:19am
it could also be a dirty injector or inproper bleeding of the fuel system had that one once before on a mitsi 4x4
snoopy221, May 9, 1:22am
is it possible for me to check balance timing conclusively via the hole mentioned without me having to remove crank pulley, lower timing cover etc!

YES.

T D C no1-both valves closed no4 valves *rocking* andthat's it.

THAT IS WHY THE BLANKING PLUG IS THERE-ON EM.

Becauseif ya pull the covers off and line up the marks that
DOES NOT MEAN IT IS RIGHT.
As explained
The counterweight is ) shaped-hence EXPERIENCED mechanics who can't be assed pulling the plug and screwdrivering em KNOW that they either fall back TOWARDS the marks-or fall AWAY from the marks-and KNOW they can EASILY be timed 180 degrees out.without either pulling the plug-or KNOWING THE **TIP**
snoopy221, May 9, 1:26am
Being ) shaped well even as posted the g) fits in there ONLY when it's right-I.E. g)and not(
roadkillcafe, May 9, 1:51am
Cool man, thanks a heap, i'll go and check it out tomoro arvo and let you guys know. Thanks so much!
snoopy221, May 9, 8:46am
Yep simple and esy TDC it n01 FIRING(no4 rocking) and re TDC it no 4 firing (no1 rocking) and see how far ya cannae fang dat screwdriver up er.

AGAIN as posted prior the **balance shaft** is just THAT a balancing camshaft speed counterweight.
And when timed CORRECTLY the weight will cause the marks to align.(FALL TOWARDS)
Seen 2 mny dmn apprntcs leave a screwdriver in em and desump em-or leave a pin punch-and naff the belt.K
SIMPLE AND EASY

POST#5
snoopy221, May 9, 8:47am
REPEATED///K
roadkillcafe, May 9, 5:27pm
I'll be going over to the van later this afternoon and i thought i'd ask to save time, exactly the location of this bolt is which i need to remove and what diameter of screwdriver will fit into the shaft and roughly how far it will go if it's set correctly/not set correctly (so i can be conclusive beyond question) t.ia
mechnificent, May 9, 6:06pm
x1
Doesn't sound like balance-shaft timing to me, it sounds like dead cylinder.
The balance shaft would cause vibration in accordance with the distance it is off from the marks, so the vibration could vary from a slight tingle to a marked hum or high speed shaking, but not I don't think the sort of shaking that coincides with one cylinder.
I'd try cracking the injectors one at a time and see if one cylinder is not firing.
mechnificent, May 9, 6:07pm
Check the simple things first!
roadkillcafe, May 9, 6:30pm
hi, thanks for your input, i thought exactly the same thing myself initially and i cracked the injector lines at idle (quite tricky while engine jumping around.) and all the cylinders seemed to be contributing pretty much the same amount, so i decided i'd eliminate the other basics and at least know that the timing as all correct. It could yet be a compression problem (i damn well hope not as that'd be a disaster seeing as cyl head brand new).cheers mate, watch this space.
mechnificent, May 9, 6:41pm
Those balance shafts are to compensate for the difference between the entire weight of piston, rod, and crank going up and down, and that lesser weight made up of the half bottom of conrod and crank which goes sideways. The counter weights are not really very heavy. I doubt they have the mass to make the engine shake as you describe. Also, you describe the shake as being like a missing cylinder. which is at half engine revs speed, that must indicate something other than counter weight. I'd think.
I will be watching with interest.
mechnificent, May 9, 7:09pm
Afterthought.

Have you checked the injector pipes are attached to the correct cylinders!
I have seen a toyota assembled with the injector pipes crossed and it ran a bit like you describe. It was drivable.