4d56 mits experts help please. I need accurate advice as to why an 3989 4d56 non turbo in a delica van would break the rocker sh

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roadkillcafe, Apr 21, 2:38am
I need accurate advice as to why an '89 4d56 (non turbo) in a delica van would break the rocker SHAFT mounting bolts (not the camhaft bearing caps or bolts though) and start wear (on at least the front cam lobe) that can begin to be felt with finger nail, all in half an hours normal running from replacement (by experienced, qualified mechanic) of head with brand new complete head (COMPLETE new head with new camshaft, bearing caps, rocker arms, rocker shaft.)it's not a genuine mitsubishi head and was bought some time back brand new but privately and has no brand name visible on it but was set up properly and camshaft measured first to check for same total lift as original, new cam belt and valve clearances set properly, good valvoline diesel oil used, had good oil pressure. It ran fine at first, then got noisy and soon after clanked quite loudly and now is as described and i need to get to the bottom of the root cause. Cam belt timing is still as it should be. Any good intelligent help much appreciated (all the usual/obvious things have been thought of, so it will prob come down to someone who knows these engines/this scenrio very well).
roadkillcafe, Apr 21, 3:06am
P.s remember it's an early 4d56 (1989), NON turbo, and an import. Cheers in advance for any good clues.
ladatrouble, Apr 21, 3:08am
Wear of the camshaft lobe is caused by rocker shaft wear - the roller runs at an angle and wears the lobe. Broken rocker shaft is caused by valves hitting pistons. But everything is new and perfect, so nothing is wrong.

Just saw your new post - I presume it's still got roller rockers if it has worn a camshaft, I don't think pad rockers do that.
franc123, Apr 21, 3:10am
Whats the oil supply like to the cam and rocker gear! The rocker shaft bolts breaking is a bit more mysterious, if piston and valve contact occurs on those its normally the rockers that snap although that seems unlikely if the engine was running ok and the cam timing was right.
roadkillcafe, Apr 21, 3:26am
Plenty of oil all around top end (sprays droplets out if you open the filler cap while it's running).Yes, roller rockers, all new, not seized or anything.
P.s-it hasn't broken rocker shaft, just the bolts which mount it to the cam bearing caps (rocker shaft is still nice and straight and rockers still rotate and slide along it happily)
roadkillcafe, Apr 21, 3:35am
P.s if it wasn't for the wear to the cam lobe i'd suspect it was just crappy quality and/or overtightened rocker shaft mounting bolts to blame.

Mind you, i guess the cam lobe wear could be down to unsquare angles of contact as the bolts broke one by one over a time period-which is what it sounded like.
ladatrouble, Apr 21, 3:46am
Only the shaft bolts! Then the wrong torque - too tight and they snapped, or too loose and shaft flex broke them.
roadkillcafe, Apr 21, 3:55am
Yep at this stage i guess that's possible, however i'm not sure that the premature cam lobe wear doesn't indicate a more deeply-rooted cause.
roadkillcafe, Apr 21, 4:05am
From memory the lobe wear wasn't glaringly uneven (as i'd tend to expect it to be if caused by wonky angle/s of rockers/shaft) but i'll have another, closer look at that wear-although i'm not where the van is at the moment and won't be able to do so untill monday morning.
In the meantime, any other ideas!cheers
snoopy221, Apr 21, 4:43am
dere a hydra daulic lifta machine aye.

metink it pumped up a coupla liftas.
roadkillcafe, Apr 21, 4:48am
No and no.
roadkillcafe, Apr 21, 4:49am
thanks though
snoopy221, Apr 21, 4:55am
mmkay yip-reread post#1 and see valve clearances set.
(Actually thought 89's were the ole dryhaulic lifta.)
So the accelerated wear on no1 afta half an hour!
mmmmmm-how the hell does a roller rocker wear!
back in the old dayze of playin cams and seein dat sorta probs.
valves gettin spring bound and cams with lobe lift diferrent between lobes.
sorta springs ta mind.
snoopy221, Apr 21, 4:57am
cld even be the actual clearance between the valve spring collett cap and the valve guide in the head at full lift.
sred69, Apr 21, 5:19am
rocker shaft fitted upside down or back to front! oil gallery runs down the centre of the shaft and feeds the roller rockers/cam lobes or a blockage from the head to the cam caps onto the rocker shaft. the single oil hole goes towards the cam belt end facing towards the cam caps, two oil holes go towards the rear of the head.
roadkillcafe, Apr 21, 5:36am
Cool, thanks a lot for that, i'll recheck all of that.
I should mention that the lobe wear i saw wasn't accompanied by any discolouring/signs of heat, it was just that i could JUST feel it with my fingernail (but couldn't quite with my finger), and wouldn't have expected any discernible wear at all at that much running.
sheepey, Apr 21, 6:10am
Is the head true!I know there were some terrible troubles with both quality and castings on some of the chinese ones available a few years back, many of the distributors stopped stocking them for a time.
fryan1962, Apr 21, 6:38am
I was wondering about the head it could be a HyundaiH100

It is pistons and valves which will cause that breakage
berg, Apr 21, 2:52pm
Another thing to check, headgasket maybe on upside down. They will fit and bolt down but if upside down they block one of the oil feed lines to the head.
intrade, Apr 21, 3:15pm
if it has worn out then i wonder how much play the bigend crank-conrod bearings have . the banging is probably these bearings. They cant have any play on a diesel as the ignition wont retard like on petrol engines it will just bash the bearings harder and harder to make em fail and brake something.
We have had a l200 mitsubishi blow up 4 times in europe no wrecker had any engine as they where all doing it. the last time it blowen up was when the oil-pickup in the sump had a crack half way up starving the engine from getting oil and it wore out and seezed . I would not even have bothered to fix that engine knowing what i know about mitsubishi.
intrade, Apr 21, 3:18pm
my theory. big end play letting oil pressure sink , no lube on head wearing rocker . and cam.run it with no cover on and see if oil is sprayed all over the place or not.
petermcg, Apr 21, 8:51pm
I have one of these vans and on two occasions I have broken the timing belt and in doing so have also broken the aliminium rockers,, so I presume these to be the weak link in the chain,, if your timing is set correct it does sound like a lubricating problem,, cam lobes take a beating on first start with a rebuilt engine, so look for oiling problem. And your bolts might have been to tight also.
roadkillcafe, Apr 22, 12:00am
I've since checked that the rocker shaft was definitely on the correct way around and up and there was definitely tons of oil getting around the overhead gear and the bottom end is fine and never made a sound before head was changed-and the noises i mentioned arent deepseated enough to be bottom end. Hmmmm.i'm still wondering why it did it.
dozerman, Apr 22, 12:11am
Is the gasket the correct grading sounds like pistons hitting head
Graded by holes in the rear end of gasket 1-6 holes.Only does it now after some carbon has built up
roadkillcafe, Apr 22, 12:43am
Thanks but i dont think so (if it didnt do it with old head then it wouldnt be logical for it to do so now with brand new head with it's clean valves, combustion chambers etc)

P.s all internal areas of head/combustion chambers, etc were measures and the same as the head that came off (while looked to be the original)