bent valves?

[black94mu]

hi guys

ive snapped a timming belt the weekend before i was going to replace it i had a new timing belt kit ready to go . the enging has not been turned over since this happed engine was under minimal load at the time it snapped. what i would like to know is there a way i can tell if the valves are bent without taking the head off . its a 1994 3.1 mu

thanks
alex

canberra, Aus

[geeves]

8 times out of ten the push rods bend instead of the valves. The 9th time the valves bend and of the 10th half the time they smash holes in the pistons. Luck is on your side almost.
I would remove the rocker gear so all the valves are closed. Any bent valves should stick down slightly. Turn the engine through 2 revolutions and note any obvious compression differences. Take each push rod out in turn place on a flat surface and roll. There is a spec but if no bend is obvious they are ok. Do note which cylinders they belonged to. Replace as req. Replace the belt and rocker gear. Adjust rockers They shouldnt be far from correct. If they are look closer. Turn engine over again by hand looking for obvious things ie one soft compression stroke. Watch the valves while doing this for any obviously sticking. Start engine and enjoy
good luck

[black94mu]

thanks geeves. because the belt snapped how do i correctly tell if number 1 is a tdc? do i take glow plug out and check height of the piston? also just to clarify did u mean turn the engine over woth no rocker gear attached?

thanks again

[pig75]

As long as the pin is pointing up as described in the PDF (Timing Belt Change for Isuzu MU 2.8TD) in the FAQ section it will be on tdc then set the cam sprocket then bolt the rocker gear down then the pump sprocket

[black94mu]

i have an aftermarket one peice pulley is that a problem? was on the car wen i bought it

[pig75]

Take a picture of this pulley and show us. i can't see how it can be a one piece pulley with a belt drive motor

[geeves]

Still undo the 4 small bolts not the large one. You will never be able to retighten the large one

[Drift]

Just for info the 2.8 and 3.1 push rods are interchangeable

I was very lucky and bent a few push rods but was shocked to find them at the cheapest £15 each and wanting 8 it was going to sting a bit.
A good friend very kindly donated his push rods from his spare and the job was finished, I wanted to replace my friends push rods so another friend saw my plight and he was ripping a 3.1 axle apart at a breakers and managed to get the push rods at a ridiculously low price (well haggled 8) ) and he kindly sent me them.

I have measured them and checked them against one of the good one's from my engine and they are slightly thicker but the same size and they fit the head, some pictures as proof 8)

The 3.1 Trooper push rod



Frontera 2.8 push rod



Both together




And 3.1 rods sitting in a 2.8 head.



Could be handy for those in a similar position, we know the 3.1 Trooper rods fit or visa versa 8)

[black94mu]

hi guys here are some pics of the after market pulley. any ideas on the tdc mark?

[pig75]

You will have to undo that bolt. Under that there should be a key way it should be pointing straight up. That should be tdc. That pulley looks like a rodeo gear drive pulley.
Holding the pulley to undo and tighten the bolt is going to be the hard part.

[black94mu]

thanks mate yep it will be a challange will have a good think about it before i jump in. just hope my engine isnt stuffed.

[pig75]

Maby find a plummer with a chain clamp

[pig75]

I would be looking at why that pulley was changed and why the belt broke. It might have a incorrect belt or gear inside. Is there anything saying how old the belt is ?

[geeves]

Its manual so put in 5th gear handbrake on and chock the wheels That bolt is torqued to 152 foot pound so expect it to be a little tight Only other way to lock the engine is to remove the starter and jam a large screwdriver into the ring gear

[black94mu]

thanks geeves i have some wheel chocks and a nice big breaker bar

[turnturn]

Can you get a dial gauge or similar down a glow plug hole to find TDC?
If so it's got to be easier than removing the front pulley.
Or does "black94mu" have to remove his aftermarket one piece pulley just to get to the timing belt anyway?

[pig75]

He will have to take the pulley off to do the belt

[steveNZ]

There is another way to remove the main pully in you case because your belt is broken you need to remove the rocker assembly so all the valves are closed
Take a good braking bar and maybe a peice of scafold bar or similar if your bar isant long enough brace the bar back from the pully between the ground and the body to the left of engine make sure its well braced and 24mm socket are properly in place
sit in the cab keeping your fingure on the engine kill switch so engine cant start one quick turn of the key and pully bolt will be releasd it should only take a small turn of the starter motor to work dont keep winding it over

this method has worked well for me hope it helps you alex

regards

steve

[98Rodeo]

uh oh, how do u stop the engine from starting? unplug the fuel pump?
mine starts off half a crank so i dont thind id be keen on this method

[Yarno]

Unplug the fuel cut solenoid on the pump.