Need help bad

[DIG]

Ok I have my AMC 304 tore down, the timing chain in it broke and now I am trying to figure out how in the hell to get the gear off the cam......I am at a loss, the book says to line up the the timing marks but if the chain is broke I have no reference to line up the timing marks, I mean the camshaft is a 1/4 of the way out any help is appreciated..thanks......

 

[CJ]

The timing marks are only for putting the chain on. Just loosen up the bolt and take the old gear off of the cam. Make note of the order of the oil slinger, bolt, washer and fuel pump concentric when you take the parts off of the cam.

If you havent pulled the lifters and have the cam 1/4 of the way out, you'll never get that cam back in without pulling the intake and pulling the lifters. I'm sure that they have locked themselves in between the lobes by now.

If you haven't pulled the lifters, stop everything, pull the valve covers and intake and remove the rocker arms, pushrods, and lifters before you do some real damage. Make sure you make a way of seperating and keeping the order of the rockers, nuts, pushrods and lifters so you can put them all back in the same place.

 

[DIG]

I have the motor torn all the way down I keep the push rods and lifters in order but not the rockers or the nuts oooppppsss thats why I cant figure out how the gear comes off because when I try and pull it off it wont come off.......... I just pull the cam out

 

[CJ]

The rockers and nuts aren't as important as the lifters.

If you have removed the bolt holding the gear and the other items to the cam, the gear is just stuck. You can fight with it or just slide the cam all the way out and put it on a bench or something so you can get some leverage. Also might just put a 3 jaw on it and give it a little tweak of the puller...

It will just pop off with a little effort usually.

 

[DIG]

damn your a lot of help, what about the little gear on the end?? What is that for the oil pump??does that come off with the timing gear? I just ordered a new timing gear from summit ( wanted to do a gear drive but not for 400 bucks) anyway do i need to buy one of those gears also ( the little gear in front of the big gear) ??? I guess you can tell this is my first motor tear down

 

[TeamRush]

damn your a lot of help, what about the little gear on the end?? What is that for the oil pump??does that come off with the timing gear? I just ordered a new timing gear from summit ( wanted to do a gear drive but not for 400 bucks) anyway do i need to buy one of those gears also ( the little gear in front of the big gear) ??? I guess you can tell this is my first motor tear down

Maybe I can help...

First take the bolt out of the end of the camshaft, and keep track of the parts that come off, and the ORDER they come off in...

Secondly, you will run into a large washer, take it off and set it aside.

Then you will find the Camshaft Gear that turns the distributor (and the distributor turns the oil pump).
If that camshaft gear is stubborn, and you plan to reuse it, then don't pound on it!
It's DUCTILE IRON, not steal, and it will mark up or chip VERY EASILY.

Use a thin point flat screwdriver between the fuel pump eccentric and the camshaft distributor drive gear...
Go around the camshaft and TAP with a SOFT FACE hammer!

Remember!
You need to TAP!
You are trying to get a CAST IRON part off a CAST IRON CAMSHAFT, so don't get aggressive!

Usually, once the 'Crud' is popped loose, the gear will move pretty easily by hand with some 'Coaxing' with a SOFT FACE hammer...

Repeat to get the fuel pump eccentric off,
Pry a little between, and in different places all the way around the fuel pump eccentric and the timing SPROCKET to get the fuel pump eccentric off.

To get the top timing SPROCKET off the camshaft,
You may have to pull the camshaft out a little, then 'Persuade' the Sprocket to come off the camshaft.

Remember to support the camshaft from the NOSE as you are 'Persuading' the sprocket off the camshaft...

DO NOT PRY ON, OR SIDE LOAD THE CAMSHAFT!
-------------------------

Once you have the top chain SPROCKET off, put the new SPROCKET on (It's NOT A GEAR!) and turn the 'Dot' directly DOWN...

Then you will have to find TDC of the #1 piston by turning the Crankshaft...

DO NOT USE METAL IN THE CYLINDER!

Just take the #1 plug out, and stick a wooden dowel rod or chop stick in the spark plug hole until you can feel the back of the cylinder wall, then turn the crank until you can feel the piston coming up and moving the wooden dowel rod...
Once you can feel for the piston at about TOP DEAD CENTER 'TDC',
Put the lower SPROCKET on and look for the 'Dot',
Which should be just about lined up with the centerline between CAMSHAFT and CRANKSHAFT...

The alignment of the dots doesn't mean a DAMN THING!
Align the dots with the centerline between CRANK SHAFT CENTERLINE and CAM SHAFT CENTERLINE

Once the CRANK AND CAM are lined up,
Then take the SPROCKETS OFF,
Put the chain on them,
And install for real...
And if the 'Dots' still line up with the CENTER LINE of the engine when you are done,
You installed the timing set correctly....
--------------------------------

NOW!
Some things you might want to know....
(Tips from a guy that has been doing AMC engines for 30 years...)

1. NEVER PUT A TIMING SPROCKET ON WITHOUT CHECKING THE OIL PASSAGE!
90% of the 'Aftermarket' Timing Sets will have 'Flash' or 'Overcasting' in the oil passage that needs to be cleaned out with file or 'Dremel' Tool.

2. Make sure the oil passage lines up with the oil passage in the camshaft!
Some oil passage are just in the wrong darn place,
OR,
The installer puts the sprocket on backwards and the oil passages don't line up!

3. *IF*...
You reuse the oil pump eccentric, distributor drive gear, ect, make sure the oil passage holes in them are in the correct place and CLEAR!
You wouldn't BELIEVE the that I've found in pumps, passages, ect. when the parts wire supposedly 'Ready To Install'...

4. Anytime I have the intake and timing cover off the engine,
I remove/replace the front camshaft bearing.
Even if I don't replace the camshaft, I replace the front bearing in the block.
(Intake has to be off so you can pull the lifters up off the camshaft)

A BUNCH of oil leaks around that front bearing when it gets worn, killing your oil pressure to the rest of the engine,
And it's just BEGGING to be replaced when you have the front timing cover and intake off!

5. Make sure the 'Oil Slinger' gets put back on the CRANK SHAFT when you reassemble.
It looks like a wide, 'Domed' washer, and the 'Cupped' side faces the timing cover, with the 'Dome' side facing the timing sprocket...

6. DO NOT forget to use some assembly lube, grease or heavy weight gear oil on the front camshaft bearing, fuel pump eccentric, distributor drive gear, timing set and front seal before you button things back up!
All that stuff will be starting 'Dry' and needs initial lube or it will burn up VERY QUICKLY waiting for the oiling system to trickle down to it...

 

[McConell]

I've rebuild many engines and would never consider, even with my experience, working without the book on that engine. You'll need the specs and procedures for that particular engine.
If you have the engine down and a chain worn enough to break, perhaps you should go ahead and replace that cam and lifters etc now.

 

[DIG]

do I need to hae any machine work done??? whats a good size cam with a good lope that i can run?

 

[TeamRush]

If you drive on the street, and/or off road very much,
I'd stick with a 'Torque' type camshaft or a 'Stock' type camshaft...

Many people use 'Recreational Vehicle' (RV) camshafts in Off Roaders.
I'm one of them.

RV camshaft gives you reasonable horse power (slightly more than stock) but gives you more TORQUE,
And Torque is what moves the vehicle...

Torque cams traditionally give up some efficiency at higher RPM operations, but since street driven and the majority of 'Off Road' vehicles aren't revving the engine past about 5,000 RPM, there is no sense in buying a cam that just starts working at about 5,000 RPM!
I'm willing to 'sacrifice' RPM power I'm NEVER going to reach for power I can use right off idle and through the lower and middle RPM ranges!

A fresh Camshaft & Lifters is ALWAYS a good idea for an engine that has a lot of miles on it...

Fresh camshaft bearings for that new cam is ALWAYS a good idea...
(and a good idea for the oil pressure too! Worn, Leaking camshaft bearings dump a BUNCH of your oil pressure!)

If you have the Intake Manifold off, It's fairly easy to do the camshaft also, since all the lifter bores are exposed...
----------------

While all the cylinders are 'Closed',
You might consider a 'Leak Down' test...
That's a test where you blow compressed air into the cylinders and see how much gets past (LEAKS PAST) the rings and valves...

Summit SUM-CSUM2601 - Summit® Engine Diagnostic Tool Combos

http://store.summitracing.com/partdetail.asp?autofilter=1&part=CMB-17-0006&N=700+115&autoview=sku



A leak down test will tell you how worn the rings are,
How worn the valves & seats are, ect....
-------------------------------------------------------

And to answer your question,
It's ALWAYS a good idea to take the heads off and have the valves done when you have a high milage engine that has broken a timing chain....

When the timing chain breaks, the valves stop right where they are since the cam quits turning...
If the valve is open, then the valve stays open,

But the crankshaft/pistons keep moving!
Often times you get a piston getting into a valve, and bending it...

So doing a 'Leak Down' test is ALWAYS a good idea to tell if there are any bent valves (you can hear the air pressure escaping past the valve into the intake runner)
OR,
Exhaust valves bent (you can hear the air pressure escaping into the exhaust runners),

OR the pistons/rings are just plain worn out,
(you can hear lots of air escaping into the crank case)...
---------------------------

There are BUNCHES of little parts that wear out over time,
Valve seals for instance...
When a valve seal fails, it lets excess oil run down on the back side of the intake valve, where it BAKES ON the back side of the valve and creates a real mess,
And blockage for the incoming Fuel/Air mixture...

If you have the intake off, you can probably look right into the intake runners and see the 'Gunk' baked on the back side of the intake valves!

So taking the heads off and having them 'Rebuilt',
Or just ordering 'Rebuilt' heads from somewhere is a pretty good idea!...
Makes a lot of sense to me!

 

[DIG]

Like whoa, thanks man! That great stuff there! I am doing all that you suggested except new cam bearings, I have run out of money so I am going to take my chances, hopefully I will be ok!