I'm caught in an argument between two mechanic shops. The first one replaced my timing belt and retimed the engine, but the '95 3.5L Montero LS would only run on 4 cylinders. One of the coil packs kept blowing. They couldn't figure out what was causing that.

I had the vehicle towed to an auto electric specialty shop. They said that the engine timing was off 2-3 teeth on both cams. I had them retime the engine and now it runs like a top, no issues with the coil pack blowing.

When I told the first shop about the mistiming problem, they said there was no way their timing was off, because that engine wouldn't run at all if the timing was off 2-3 teeth. The first shop thinks the auto electric shop is lying about the timing and ripped me off on the 5 hours they said it took to open the engine and adjust the timing.

I'm trying to get to the bottom of what happened as I'm getting different answers from the two shops. What's the TRUTH? Can a Montero engine run at all if it was 2-3 teeth out of time?

 

The rule of thumb is - the engine will run with 1-2 teeth off timing. It will run and idle like crap and you'll have misfires and CEL illuminated. When you get past 3-4 teeth off it will not run, but even worse - you are will likely have bent valves due to piston/valve contact. My guess is the 3 teeth is just on the very edge of not hard smacking the valves,or perhaps, just touching the tops of pistons near the top. I can't explain why this would result in blowing up the coil packs when the timing was off.

One time (first time) when I didn't set my timing correctly (it was off by 1 or 2 teeth), the engine ran poorly, had misfires and I noticed that exhaust manifold started to glow red. My guess the exhaust valves opened too soon and the combustion cycle finished in the exhaust manifold

 

I checked back with the electric shop. Their invoice says the Montero was 1-2 teeth out of time (not the 2-3 teeth they told me over the phone). Apparently (based on your comment, Hunter D), out of time just enough to run badly, but not enough to not run at all, or run and wreck the head/valves.

Thank you for your input!

 

That is a good news - there is no chance of valve damage with that. Glad you got it sorted out. I think the first mechanic shop should pay the electric shop for timing job

 

Just did my timing belt, because the last one broke at 25k miles. Yes, and had to rebuild both heads because it broke doing 70mph. Make sure you use a quality belt when replacing.