AMC engine guys

guffey24

guffey24

Well-Known Member
Joined
Jun 7, 2006
Location
Hendersonville, NC
401 wont crank

Alright guys, I am not sure where to go with this

before I rule out the obvious

I will start here

I have fuel, carb probally needs a rebuild after sitting for a while

I have spark

I started retracing my steps when I was rebuilding the motor to figure out If I had done anything odd or missed a step

I built this using a great book/soft copy of

BJ Builds An AMC

well I get into the section where it starts talking about installing Cam/Timing gears/Drive gear

I did everything by the book so I thought

I didnt retard or advance the timing so I set the lower gear on the zero mark

this is the step that I got ahead of myself, I honestly didnt pay attention to this. I slid the chain, and gears on as a complete unit

[next step says engage the chain while trying to line up the timing gear marks. The mark on the lower gear should be closet to the mark on the upper gear. Then slide the gear on the cam snout. Look at the gear alignment closely. Make sure the marks are in a straight line with the cam and crank. If it's off, then remove the cam gear, skip the chain a tooth and re-install it. One tooth off is bad news!]

Did I screw myself or what?
 
Guffey,
I think the timing chain install is hard to screw up personally., but I could be wrong.
When you say it won't crank do you mean you get no rotation or it won't fire? Is the starter turning? If no, do you have it fully engauged in park?...could be the neutral safety...thats one thats not so obvious it gets people. What ignition system are you using? Could be a bad box? I guess there is a ton of more obvious stuff, but lets go from here.
You sure type a lot for someone with a bum finger :rolleyes: j/k
 
etjeep said:
Guffey,
I think the timing chain install is hard to screw up personally., but I could be wrong.
When you say it won't crank do you mean you get no rotation or it won't fire? Is the starter turning? If no, do you have it fully engauged in park?...could be the neutral safety...thats one thats not so obvious it gets people. What ignition system are you using? Could be a bad box? I guess there is a ton of more obvious stuff, but lets go from here.
You sure type a lot for someone with a bum finger :rolleyes: j/k
Click to expand...

took me about 30 min to type all those words, I copied and pasted it from another web site to here when I was done

I have alot of people telling me that my cam timing is off
 
I would check the ignition box. If it crapped out on you that could be your problem. If you think it's your timing twist the ditributor until you get what you want.

Also check here: http://www.ifsja.org/forums look in the tech help. They are gurus of the old iron.
 
I was there trying to help him get it cranked. Thats probably the first problem! LOL JK
Anyway. It turns over and it seems to fire, but when you let off the key, it dies. When I say it seems to fire......It tries to start, popping and spitting, but never gets right. Seems like timing is off. We put it at top dead center twice but still didnt help. Even pushing and pumping the gas pedal doesnt help.
 
guffey24 said:
took me about 30 min to type all those words, I copied and pasted it from another web site to here when I was done
I have alot of people telling me that my cam timing is off
Click to expand...
Hahah,
Maybe your 180 deg out or something. I guess I would check your plug wires while your in there. Like Nick said, you should be able to ear tune it until you get close if you have fire.
 
i would check the distributor for firing order. Sounds like it might not be good. You can always do it the old fashioned way by sticking your finger on the first cylinder hole and feeling when the piston comes up then putting the wires on the distributor to make sure. you probably know this but i figures i'd throw it out for folks that don't know.
 
I still think you are 180* out and it is trying to fire on the exhaust stroke.
 
As said above, make sure compression stroke is on number one, and that the right plug wire is there on the dizzy. The popping and cracking as you describe is a timing issue for sure. Something else to think about, I know you did some performance mods and installs when you built it. The cam it's self may need to be degreed to get it to fire correctly.
 
firing order is right unless I am 180* out,

I really dont think that I am 180* out, reason being

first time I tried to crank it, it was 180 out, when the exhaust valves were open it was pouring gas out of the manifolds
 
upnover said:
As said above, make sure compression stroke is on number one, and that the right plug wire is there on the dizzy. The popping and cracking as you describe is a timing issue for sure. Something else to think about, I know you did some performance mods and installs when you built it. The cam it's self may need to be degreed to get it to fire correctly.
Click to expand...

Chip explain degreeing the cam to me please, I didnt do anything like that
 
alright looking at my old set of timing gears and chain I am seeing 2 little dots, one on the camshaft gear and one on the crank gear

these 2 dots need to be lined up for proper timing

damn I hope I didnt screw anything up

timing cover is coming off and well see what it looks like
 
guffey24 said:
Chip explain degreeing the cam to me please, I didnt do anything like that
Click to expand...

To be honest, I can't. The shop I worked at did everything engine related. I know when I saw him build an engine, he always degreed the cam. From what I understand, it puts the cam in the right place to get the valves open at the right time, to optimize the whole sequence.
When I built mine, I used everything stock so there wasn't an issue. I did just like you said and lined the two dots up. I think pulling the timing cover off is a good idea. I would also pull the valve covers off to make sure you have not bent any pushrods.
Did you replace the dizzy gear and the cam gear, that drives the dizzy? the are known to wear due to poor oiling design.
 
guffey24 said:
when the exhaust valves were open it was pouring gas out of the manifolds
Click to expand...

Umm, that sounds like a problem.. plugs fouled out now? carb just dumping fuel?
 
upnover said:
To be honest, I can't. The shop I worked at did everything engine related. I know when I saw him build an engine, he always degreed the cam. From what I understand, it puts the cam in the right place to get the valves open at the right time, to optimize the whole sequence.
When I built mine, I used everything stock so there wasn't an issue. I did just like you said and lined the two dots up. I think pulling the timing cover off is a good idea. I would also pull the valve covers off to make sure you have not bent any pushrods.
Did you replace the dizzy gear and the cam gear, that drives the dizzy? the are known to wear due to poor oiling design.
Click to expand...

yeah I am going to pull the timing cover and connect the dots and I will pull the valve covers and check all the push rods for a safety measure

I replaced the dizzy with a new one and the cam gear was also replaced, I feel like such an azz for doing something stupid like this, especially since the book was right in front of me
 
Friend of mine had a similar problem on his, did you back the distributer up before installing it. I think it's like 1/8 turn or 45 degrees or so. I'll post it up when I get home tonight and look it up.
 
Thats what made me think you 180 out, the gas dumping out the pass side manifold.
Have you already tried it 180 from where you first had it?
 
uglyjeepoffroad said:
Thats what made me think you 180 out, the gas dumping out the pass side manifold.
Have you already tried it 180 from where you first had it?
Click to expand...

yeah I got #1 top dead center right now

I am almost positive that the timing chain is way off

I took it out of the box and didnt even look to see where the dots are that are supposed to be lined up for correct timing

I just set the cam shaft gear to 0 and didnt pay a bit of attention how the crank gear went on
 
degreeing a camshaft really does nothing more than make sure the cam is cut properly.

If cut properly the degree wheel does nothing but confirm.

if you had valve timing off very much, you'd probably be having valve piston relationship issues.(they'd be ready for a divorce)

Id check timing, again.

then if you feel froggy check compression. If your valve timing is off. the valves will be open when the cylinders are compressing, and you will build no (very low)pressure.
 
I tend to agree with the timing off 180 degrees. When I rebuilt my 360 I did the same thing. Paid close attention to everything. Thought if I put the timing mark on zero it would be tdc. Tried to start and had the same symptoms as you are experiencing. After checking everything and pulling the distibutor, I pulled the #1 plug and made sure the cyl was tdc. Installed distibutor and the thing fired right up. Felt like a dumn *ss, but got it running.
Good luck
 
From the school of hard knocks:

Are the distributor wires installed, in order, AND in the direction of distributor turn? Some distributors turn CCW and others turn CW (Pontiac vs Chevy)

If timing chain and gears are right, turn motor in CW direction until TDC. Moving it more should immediately start opening the #1 exhaust valve and the distributor rotor button should be at #1 wire. If not, you are 180 out or half way through the 720 degree crank cycle.

Are your ground wires all attached?

Really sounds like crank and cam sprockets are not set to correct relationship.

My $0.02
 
Really sounds like crank and cam sprockets are not set to correct relationship.


that is my thoughts also

everything else is right on, TDC to #1 and all the wires are in the correct position
 
ok before u pull every thing apart pull no one spark plug stick ur finger in the hole bump the engine over untill it pushes air out then stick a screw driver in the hole turn the engine over by hand in the direction of rotation (the direction the engine would normaly turn) turn by hand untill its at top dead center pull dist cap make shure rotor button is pointing to no one plug wire if not then turn dist untill its at no one and install cal and plug wire try to start engine if something is off int it would bind when u turn the engine over normaly after that the engine should crank and then set it with a timing light
 
Well turns out I was way off when I installed the timing set the first time

that thing had no chance of firing, the timing marks where about 6 links away from lining up right

thanks to Chris

uglyjeepoffroad for helping me tare the front part of the motor back down to find the problem
 
Back
Top