My van is a 67 a108 van with a 318 in it. Here it is.. it has been driving well until today.. I was driving down the road, came to a stop and the van was idleing but shaking like crazy I pulled away from the light and about 1/2 a mile or so up a hill, all of a sudden the van backfires twice very loud! It dies, so I pull over and now it wont start. It turns over fine and normal, but I can hear this like compression sound like whooomp, whoomp, out the exhaust avery few cranks. I have spark and fuel. did a valve drop or burn? Timing chain? Any Ideas?? thanks
318's with lots of miles........first thing that comes to mind is you stripped the teeth off the timing chain. find TDC #1 and check the distributor to see if the rotor is pointing to the #1 plug wire in the cap. if not, pull the front of the engine down and check the timing marks on the crank and camshaft. if it stripped a bunch of teeth, it probably bent some valves too.
318s are notorious for frying the ballast resistors, might be worth checking...but it may be something more.
You can still have spark, just not great spark, which in turn makes it run like crap, then it heats up and kills the spark, then it can cool off and give enough spark again... like i said...may be something more
Flippen hell I was hoping it was not those whoomp, whoomp bushings! Those are a pain in the ass to change! I did not know how else to describe the sound... sh*t. I have to get it back to my place first then I can check it.. But I will start with tdc. I do not know how many miles were on the van. It was running fine, great actually right up until this... that would suck if it was that... How can I check to see if valves are bent with out taking them off? I love these vans but working on the engines not the easiest thing..
Compression test will tell you if the valves are operating or not. Good thing is that you can find a 318 almost anywhere in the newer vans and trucks for the heavy parts.
Well now that you mention that. the spark is a yellowish (is that a good description)? color not blue.. I did pull it out of the coil to check spark and the first time i did it fired up for a very brief second but then did not do that again.. Like I said I have to get it back to my place then I can check tdc. and I just realized that doing a compression test will tell me vales or rings.. duh...
Not to sidetrack the thread but I've never ran across this, always just had them quit altogether, good to know. Always learning, the great thing about this place!
That van looks a bit loooong...is that an opening door behind the driver door? or just an extension section of some sort. I don't recall ever seeing such a door option back in the 60's. As said, if the engine has suffered any damage then just toss in another 318 or even a 360 (but be aware of converter balance issues). .
its just an extension thats all. its a 108 so its the longer wheel base van. it fits my motorcycles in the back quite nicely. and it was so easy to lower because of factory power steering. a price i could not refuse. I hope i don't have to re and re the engine. if I do any one know someone here in cali that can do the work? I don't have time or space for that kinda job. I am in the ucla area..
Hell man, it's a 318, if you need a new one, there's probably one layin out by the curb they're so common! : )
Timing chain,...and the ones lying at the curb sometimes have better ones........if there is spark, rule out ballast resistor,..when those go bad, it's like you just turned off the ignition switch..... 4TTRUK
Jot me down with the timing chain crowd. Air rushing past bent valves sounds kinda "whooshy". Happened also to a 318 I once knew.
you have to be kidding about the engine being hard to work on... it's right there in the cabin with you! i had one of these (wish the hell i still did) and had the dogbox off more than once to do various things including replacing freeze plugs and flexplate.... best damn truck i ever had.
It's right there beside him but if he has to pull it that's a royal pain in the ass. I'm with the plastic on the cam gear going away. It's best to pull the pan if it did because those chunks of plastic head straight for the oil pickup screen when they leave the timing gear.
As a general comment, when a chain goes the engine should spin over faster than normal & be pushing a lot of vapor back out the carb.
It seems that there is an abundance of SoCal types on this board so hopefully someone can lend a hand, or at least point you in a good direction. Perhaps a beer and pizza 'reward' party following the finish work would entice a couple of the guys...or girls. .
If you're lucky it could be the rotor, check the brass contact. I had one break almost off and it gave the same symptoms as a timing chain.
Ok so here is what I have found so far. Turned it over with the cap off and the rotor turns, so thats good. also got it to what looks to be top dead center. I can´t hold the pressure from 1 cylinder compression. but when i get it to compression stroke and the timing mark right at zero (middle of the timing hole) the rotor is pointing straight forward, not to the left or right but dead ahead. Which is very close to where it should be for plug wire #1. Do you think this means that the distributor broke a tooth or something? Or still timing chain? When I bought the van the previous owner said (as they all do, but this pretty old guy was the original owner) that the engine was rebuilt about 15,000 miles ago. He said he rebuilt it because he needed to tow his new boat. but stopped using it because it would not stop very well. And there it sat till I scooped it up. Why did i just say all that? Because could it really be the timing chain that early on? Yes but unlikely, no? Anyway those are the findings I have right now. What does everyone think I should do next? take out the distributor? The front of this engine is a flippen pain to get to so I don't want to pull the cover off unless i really have to.. At that point I don´t know any of you, but I am happy to host a help me out party with pizza and beer at my house or warehouse! Thanks so much everyone!
The crank turns the cam via the timing chain. If the chain was gone the cam/dizzy wouldn't turn at all, or should be inconsistant turning if partialy stripped. Might turn consistantly if it "jumped a tooth" but never seen that happen myself.
Oh the denial of it all.... Do the compression check, my bet is that you will have consistently LOW readings across the board due to the timing chain slipping a couple on a few teeth. What one mans calls a "rebuild" is another man might call a re-ring.... 15,000 miles is too soon for a good timing gear to go south, but if the rebuilder thought the chain and gears "looked good" they might not have gotten changed. (or they might have replaced the set with a NOS fiber set that has sat on a shelf for 40 years) A compression checker can be bought cheap enough, and if you can change plugs, you can do a compression check.
First things first,,,keep it simple and check dist. cap for cracks and carbon tracks which look like cracks,,,,,this will easily cause the same problem,,,,or just start with the hard stuff first before you find the easy stuff,,,just an old mechanics 2 cents...
Unless an original and very looose chain was re-used the chances of jumping is nil. If it is a plastic gear and failure occured then the dist will not move. There is zero opportunity for the 'dist gear' to change position. You could verify valve operation if you pull the valve covers and slowly spin the engine and look for issues. This is best done with all of the plugs out, but, you could then do a complete comp check as a double check. This leaves ignition. Is it still a points system? or has it been changed to electronic? Points do not usually fail all at once, electronic parts can and do. Beyond that I am leaning toward the whooomp whoomp bearings... This is a good mystery, lets get it figured out. .
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