Delica Canada | Mitsubishi Van Club

marsgal42 wrote:I agree: if you don't know how old the current timing belt is, replace it. Diesels are intrinsically interference engines, and breaking a timing belt is bad news. Japanoid replaced all the belts before Gumdrop left Japan.

My VW Jetta is not an interference engine: if it breaks a timing belt, the engine just quits.

...laura

Laura, I wouldnt be so confident... i learned my timing belt lesson on my 91 jetta, after 230,000km on one timing belt i destroyed the engine when it broke... so are you sure your jetta is a non interferance engine? all my valves got bent. Of course my jetta was a gas one... so who knows.

Josh

Even though the 4D56 may be an interference engine, the valves enter the head almost vertical. Any contact with the pistons tend to push the valves straight back up which results in smashed cam caps and rocker arm, but the valves/piston remian intact/unbent most of the time.

This means you don't have to take the head off if you want to rebuild it? Cam caps and rocker arms can be replaced with the head in place, meaning you minimise the amount of work in the rebuild compared to getting a new head.

In the case of a lot of other engines, because the valves enter at an angle....the piston makes a right proper mess of everything when it makes contact. Bent valves, snapped valves embedded in the piston, smashed head from newly embedded valve being pummelled into the surrounding metalwork before the engine cuts out......

Here are some shots of the head on the Mystery Machine when the balance belt went:

Cambelt still on the pulley...


But where the balance belt had got caught in the top pulley, the cambelt had stopped turning with the engine!


This caused the pistons to smash the valves into/through the rocker arms.....


....and also smashed the cam caps (all 5 of them!!)


The cam lobe had also been smashed off:


A few sets of second hand cam caps, rocker arms and a cam meant I was back on the road with the minimum of fuss. Cam caps are machined to match the head and cam, so you need a few sets of cam caps to mix & match in order to find ones that will fit perfectly on the cam. Anytime my friend has a dead 4D56 engine, he always keeps the intact cam caps, rocker arms and cams for future rebuilds.....

Hey Bruce

Looks like your belt was shredded quite a bit. The width is about 1/2 of mine. it's good of you to relate this problem on the forum. We all need to know about the problems and solutions.

Did you have any problems pulling your crankshaft pulley? Eric and I popped his off easy with light persuasion but mine is stuck tight. I'm wondering if I should heat the pulley then try. Any ideas?

I bought a puller but may end up removing the radiator (lots of extra problems). The normal pullers are all too long.

Thanks
Wayne

josh wrote:

marsgal42 wrote:My VW Jetta is not an interference engine: if it breaks a timing belt, the engine just quits.

Laura, I wouldnt be so confident... i learned my timing belt lesson on my 91 jetta, after 230,000km on one timing belt i destroyed the engine when it broke... so are you sure your jetta is a non interferance engine? all my valves got bent. Of course my jetta was a gas one... so who knows.

There were several different gas engines in A2 Jettas. The GX (U.S.) and MZ (Canada) engines were non-interference. All the others were interference engines.

My policy is to assume the worst, and be religious about timing belt changes. The only hard part on the VW engines is those %^^&^*^* little allen bolts VW used everywhere, including the crankshaft pulley. Good luck getting them out without stripping their heads!

...laura

Wayne, do not use heat, you will destroy the rubber in the pulley. Just use 2 prybars, one on each side of the pulley and walk it back and forth gently.

Eric
Tried to rock it off, ended up using a puller. Call me if you ever need a puller for the crankshaft pulleys. I never tried heat. All these pulleys and gears are tighter than yours were.

My front oil seal is shot and needs replaced. That too looks like it needs a puller, if I can find one. Do you have a 4", 2 or 3 prong puller?

Wayne