Blown 2 Timing Belt, Won't Run

I have a strange issue with my g63b.

I finally got all my timing belt issues sorted out this weekend, new belts, and new ignition, and made sure everything was in order for me to try to start it.

turned the key, fired right up, but only idled for a second, before the rpm shot way way up. mine don't have a tach, BUT, i would estimate to around 4k (my foot was no where near the accelerator, and the cable was NOT stuck) THEN, a loud pop, and what sounded like a piece of paper stuck in a fan....again. This is what happened the first time the belt went.

The main timing belt detonated at the crank.

I want to know what could possibly cause the rapid acceleration, with the choke on (stock carb), because I really don't want to put a new belt on, just to have it do the exact same thing.

everything was set in time, everything was tensioned up right, nothing seemed to be sticking or any other issues.

The firing order I figured out was 1,3,4,2, with the distributor pointing to the right hand side plug at TDC. This was different than what I thought it should be, thought #1 should be straight down. Could my timing be way way way advanced, firing order be off, causing vibration in the belt...i dunno. just hypotheticals.

If ANYONE has any idea at all, hit me up, I'm all ears.

Balance shaft frozen? woodruff key sheared?

everything felt good, i guess. the oil pump and the balance shaft both turned relatively easily. I didn't check out the keyway on anything other than the one on the crank, and it was perfectly fine. The high revving is what really has me worried though, don't want to put another belt on, then have it crap out again.

leaking intake manifold gasket's my guess???

That would probably explain the increase in revving, but the truck was running fine before it blew the timing belt off the first time, so I'm not so convinced. I did have the vacuum line off that was going to the bottom of the air cleaner housing, is there a one-way or something in there that would block it off to keep it from revving? I also tried to use starter fluid when it first wouldn't start, so I dunno if that might have something to do with it too, but I haven't used it in over 3 weeks, and the truck has been sitting with a rag shoved in the carb so it should evaporate a little bit i figured.

I've attached a picture of the firing order I've currently got going on, and seemed to make it run pretty good. all the other suggestions from the manual wouldn't start. BUT, this order doesn't seem right, because the manual wants me to have the rotor button pointing down and to the left, and mine is more to the right, kinda west southwest.

Attachment 3671

I'm still lost as to why the timing belt would have went, my only guess is that there was some resonance in the crank because firing order was off so it tried to go backwards or something and stripped the teeth again.

I don't want to waste more time putting on belts until I can get some idea of why it has went twice in the same manner. I'll check out the intake manifold to see if it has a bad gasket or something.

Thanks for the help guys.

If the cam timing was off then that might make it rev up. But the belt ripping might be because the belt was not at the correct tension or somthing is frozen. When you tensioned it how did you check it? The belt should just rotate a little past 90 degree on the long side. was it one belt or 2 that went?

When I put the main belt on, the manual said to keep the long side tight, and after I slid it on, and let the tensioner down, i checked tension by pulling on the middle of the belt where the manual shown and measured deflection. IT did seem like it wasn't tensioned enough when i was tugging on it, but it measured OK with a small scale (at the upper limit, but still within bounds).

I'm not sure what you mean that "The belt should just rotate a little past 90 degree on the long side".

Both belts went the first time, I thought that the balance shaft belt may have took out the timing belt, then though. The second time this happened (after 30 seconds of running), the balance shaft is OK, but the main belt stripped at the crank.

So you have blown off 2 sets of belts now? There must be somthing causing this. Can you get us some pictures?

yeah, it blown the original belt, which I assumed went because it was old/balance shaft belt took it out. But then, after putting the new one on, it took it too.

What can I get you a picture of? I'll get anything and everything you possibly want, I can even get video of me turning all the pulleys if need be.

somthing so we can all see if there is somthing out of place. There must be a reason why it went out the 2nd time.

Sorry for the delay. I had kinda quit caring about this truck, until I recently acquired a 240sx that needs work, and now I have no where to do it because this truck is just hanging out in my garage.

I've included pictures of the crank, camshaft pulley, dizzy and oil pump, and a video of me turning both the camshaft and the crankshaft over.

Hopefully ya'll will be able to see something I dont.

My main concern i think is the dizzy, its sitting 90' off of where the manual says it should be at TDC, but there may be something else I'm missing that's causing it to be over there. Ya'll have a look and let me know. Thanks a ton.

http://s14.postimage.org/c5xspxuyl/I...110_174750.jpg
http://s14.postimage.org/5usl9itq5/I...110_173955.jpg
http://s14.postimage.org/5w2j2xvjx/I...110_173823.jpg
http://s14.postimage.org/4jku11y4d/I...110_173752.jpg
http://s14.postimage.org/i1rqdca9p/I...110_173734.jpg

Video Link
http://www.youtube.com/watch?v=JqmGB...ature=youtu.be

Yes the distributer looks like it's 180 out.
Has the distributer been removed during the belt change?
Does the balance shaft turns?
Is the balance shaft woodruff key in good shape?


The hissing noise normal. Thats compression leaking past the rings.
The squeaking noise concerns me. You need to try and locate what it is.

OK. I'll look into the distributor, it was never touched when the belt was put on, just had the cap removed to see if it was pointing at cyl. #1. it was the first time, then after, it looked like the post above, but when I went out there to take them pics, it was pointing over to the side. The balance shaft turned around freely, (the pulley that the secondary timing belt is attached to? - if not, then what I called the oil pump turns freely, acts as if it has a weight on one side takes 2 turns to get it to line up with the timing marks, and it settles on one side.)
I'll have to pull the balance shaft pulley to look at the key. When the truck started up before it ate the belt, the engine was running smoothly, and the main belt got ate off at the crank, the secondary belt was unharmed.

The squeaking noise was very rubbery sounding. It's not a metal on metal squeak, and really sounds like 2 pieces of rubber, or rubber on metal. was kinda thinking it might have been the front main seal squeaking against the crank because it only does it if I turn the crank pulley really slowly.

It sounds like the counter shaft is ok. I don't think the key is broken. You would see things where the bolt goes in. The oil pump should give a little resistance and the counter shaft is a of center weighted thing. If the marks are aliened according to the book. Stick the belt on and look to see how the alignment is. They make 2 different types of belts. one with a round rib and another with a flat rib. It looks like the cam is a round rib but the crank is square or flat. Can you confirm this? You might want to ask LSR Mike what belt would be the best in this type of a scenario. Or finding the proper pulleys if they are mis matched.

I would definitely agree with that statement now that you mention it. it really does appear that the crank would take a flatter profiled belt than the cam pulley. These are the stock pulleys I can confirm with 100% certainty, so would Mitsubishi screw something like that up? I'll go get another belt today, put it on there, and take some pictures. Both belts that went were round profiled ones, but the first one was not the original OEM belt. The PO had changed them out before, so I'll cross ref. some part numbers until I can find a flatter one hopefully.

we have seen this before on an old post and he found it was a gates T013 122 tooth Trapezoidal belt not the Curvilinear belt.Hope this helps.

I want to say that you can use a Trapezoidal belt on a Curvilinear gear, but you can't use a Curvilinear belt on a Trapezoidal gear. As for Mitsu having the wrong cam gear. Have you owned the truck from the dealer when it was new off the lot? If not who knows what may have happened over the last 28 years. New head, truck was crashed and broke the cam gear, who knows?????? :{? It might be worth looking at the other belt and checking to see if it is correct. My self I would want all the parts to match. round to round, square to square. But thats just me. Might be worth looking at the junk yards to find the correct cam gear. Ya never know...

Do you have the old belts laying around? Get us a picture.. We like pictures. It helps the next guy avoid problems.
If you still have the old old belt check the cog shape.