engine trouble
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engine trouble
ok ill start here, i recently purchesed a 351w motor for my 86 f150. the motor was from a 89 ford car and was carbed but the previous owner told me that he installed a thumper cam into the 351 but never started it. so i snstalled the motor and went to start it and it would not start on a 351w firing order. so i got the bright idea and tried the 302 firing order and the motor started but would only run for about 5 secs and die i have tried every thing to get the timing right but it wont run any suggestions
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From: Northeast, OK
When it starts does it sound like all cylinders are firing? IOW, that the firing order is what the engine wants?
If so, I'm guessing that you have one of two problems. First, that the initial timing is off. Where is the vacuum advance connected? If it is to the manifold the 5 seconds might be just enough time for the vacuum advance to take the timing too far and the engine stalls.
Second, you may be running out of gas. When it dies have you checked to see if the accelerator pump still shoots gas? If so, you have gas. If not, you either ran out or the pump is faulty. Anyway, install a clear plastic filter ahead of the carb so you can see the gas and tell if you are getting enough. Could be the pump, could be a plugged filter.
If so, I'm guessing that you have one of two problems. First, that the initial timing is off. Where is the vacuum advance connected? If it is to the manifold the 5 seconds might be just enough time for the vacuum advance to take the timing too far and the engine stalls.
Second, you may be running out of gas. When it dies have you checked to see if the accelerator pump still shoots gas? If so, you have gas. If not, you either ran out or the pump is faulty. Anyway, install a clear plastic filter ahead of the carb so you can see the gas and tell if you are getting enough. Could be the pump, could be a plugged filter.
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brand new fuel pump and all my timing marks where rate on, so i think tomorrow im goin to pull off the new water pump and timing cover and double check to make sure the crank and cam are lined up right
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ok i removed the timing cover and spun the motor over 4 times and the timing dimples never lined up? does this mean i need to take the push rods out and set the cam gear to line up with the crank gear while at tdc?
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From: Charles Town, W bygod Va
You dont need to remove pushrods. I'd put the cam where it needs to be, then remove the chain and gears. Slowly rotate the crank to tdc, if a valve hits a piston you should feel it. Reinstall chai and gears. Removing spark plugs will make it easier to turn the crank but you dont need to.
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From: Charles Town, W bygod Va
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Ok I see what it saying rotate the cam till the dot is on bottom then remove the chain and rotate the crank till the bottom dot is on top
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Ok i am looking at the chain and gears rate now it is a double row timing chain and the crank gear has 3 slots to fit over the ridge in the crank each of the 3 slots has eithe a square triangle ans a 0 above them
Posting Guru
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From: Wagener, SC
Oh, and make sure you do a proper cam break-in procedure after you get it to fire up. You don't want to wipe that cam. How long has it setup since he installed the cam? The lobes might be dry now...
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the cam gear has 3 slots in it,one slot has a square,one has a triangle and the third has a 0. when i turn the motor to tdc on the compression stroke the slot that lines up with the cam gear is the suare not the 0.should i set it to the 0 slot
Posting Guru
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From: Wagener, SC
It seems to me it would be the '0'.
Also, I know you said the cam is a "thumper". What is the exact model number? You may also need to look up your cam and make sure which firing order it is ground for.
If you know what everything is expecting, you don't have to guess. Easier to get things right that way.
Oh, when looking at your timing set, look at the teeth. One of them should have a dot on it, which corresponds to a dot between the teeth on the other gear. These are the dots you have to line up. The key'd slots are for the timing event.
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I'm not sure who makes the gear set I bought the there was no dimple on the crank gear only 3 slots with either a triangle square or 0 above them I just need to know if it should be set to the 0
motor from a guy who put the cam, I saw the cam sheet is said 481/491
motor from a guy who put the cam, I saw the cam sheet is said 481/491
