’85 Bertone Timing belt broke, big backfire when I try to start it

B

bavaria72

True Classic
OK, I changed the timing belt and the idler pulley a couple of months ago and she had been running fine. Unfortunately I did not tighten down the idler pulley bolt enough and it loosen, the timing belt walked half way off the cam and grinded itself to death until it broke.

So new idler pulley on (lock tight applied!), timing marks lined up correctly, distributor pointed at #4 plug but when I try to start it, the car tries to fire then a huge backfire. She was running fine before hand any suggestions? I can get her to run with the distributor pointed way past #1 plug but no power.

Thanks - Art
 
big backfire

You could have the cam 180 degrees out. Make sure the timing mark on the flywheel is at zero when you put the belt on.

MikeR ('86 X)
 
Are you sure you have the dizzy is pointing to #4 and not the opposite direction? I made this mistake couple weeks back while changing a belt and had the same problem.
 
That is what I'm thinking but wanted to double check before I did anything. Will try again tomorrow! Thanks - Art
 
!

This is pretty simple. The crank needs to line up with the timing mark, and the cam wheel needs to line up with it's mark. You can't mess that up.

Make sure that the "plug #4" is actually the plug next to the transmission (on the left!). Plug #1 is on the right next to the belts.

OK?
 
Yes, exactly what everyone has already said. Do NOT use the pics I posted for Charles to get his running as a guide. http://xwebforums.com/forum/index.php?threads/11476/
Those pics were for a very special one-off situation where Charles doesn't have the proper timing marks on his car and we had to improvise. Cam to the top pointer ("real deal" in my pics) with the engine at TDC (double check the dimple in the transmission window) and dizzy to #4. You didn't mess with any spark plug wires in the process by any chance?
 
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bavaria72 said:
when I try to start it, the car tries to fire then a huge backfire. She was running fine before hand any suggestions? I can get her to run with the distributor pointed way past #1 plug but no power.
Click to expand...

Poster child for cam timing wrong... The backfire happens because the sparkplug is firing in a cylinder that is at TDC at the top of the exhaust stroke, all full of unburned fuel and with both valves open.

You have a 1500, so you want to use the cam timing mark at the top of the motor (little metal finger on the timing belt cover mounting bracket). Do not use the cast finger on the snail mount (and if you do, you will get EXACTLY the symptoms you describe: backire when setting distributor to #4, runs like crap when you set it to #1).
 
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+10000

fiatfactory said:
posted a while back, this has a good step by step with pictures...

Follow the link in this thread...

http://xwebforums.com/forum/index.php?threads/10795/

SteveC
Click to expand...

Second this one. Don and others did a nice tutorial that is priceless. I have done easily 20 timing belt and or timing setups on X's and I actually found I was doing a step wrong (10 degrees BTDC when setting distributor was done incorrectly).
 
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Thanks for all of the info. Been on the road for the last 2 weeks (Chicago and Wisconsin!) and finally got a chance this weekend to work on the Bertone. Set the time markers correctly and pulled the distributor out so I could point the roter to the "correct" #4 cylinder and sure enough busted the distributor gasket. Well more like it fell apart in my hands. So I'll be making a trip over to Vick Autosport tomorrow to get a new gasket. Dang shame too because the weather was wonderful this weekend in Dallas! Fingers crossed for next weekend! Thanks - Art
 
Running well now!

Thanks to all of the folks on this forum for helping me because the little '85 is running great now (revs are a little high though). Bascially the issue was I had the dizzy pointing at the wrong spark plug. As soon as I figured out it needed to be pointed at #4 she started right up. Thanks for all of the support! - Art
 
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