Finally getting back to the engine on my 73 coupe. Pulled the front cover and found the timing chain jumped 180*. Still the original teflon cam gear with some pieces in the oil pan but not too many.
So a new timing set and send out the heads. Guess I should also pull the lifters and see how they look.
Strange how the car started right up and only had an off idle miss in park. It felt like it was going to fall apart at about 50 MPH though. Timing was set with the rotor pointing to #1 cylinder and crank at TDC then adjusted to 8*. I would think the distributor would have had to been set 180* off also for it to run.
It would have had to been 180 off to run if the cam was 180 out. Remember the crank is at 0 2x for every time the cam is at 0. The reason it was so rough was likely that with so little of the teeth left and how loose the chain was you had +/- 20 degrees in the timing depending on which way the chain bounced.
If its that far apart may be worth pulling the cam all the way out for a look. This was the prime era for GM having bad cams that went flat. About 1/2 the 70's cads I have had apart have had at least some signs of cam issues. Only one that had a few lobes missing. What I usually see is a few lobes with bad pitting and worse wear than the rest.
Make sure you are getting a Cloyes timing set. It does not have to be the fancy roller (bicycle chain) one, they make a stock link belt type one that is fine for a stock engine. There have been several people that have had the crank sprockets just shatter when they have used 'regular' parts store sets. Many people this happened at installation but a few folks have horror stories about the carnage when it happened with the engine running especially on a 68-70 engine.
OK but right now #1 cylinder is at TDC, crank at TDC, and cam mark off 180*. So what does that mean? Jumped or not?
Sounds like it is on #6 firing, not sure of the firing order here, but the # 1 piston can be at tdc and the balancer mark on but you are not on #1 tdc firing. No way it runs truly 180 out.
Before I took it apart I set it up like I thought it should be. I have a TDC indicator in #1 cylinder spark plug hole. It stopped at its highest point and crank was at 0*. That should be good, right? From there started pulling everything apart. Cam gear has indicator at 12 o'clock and crank gear is at 12 o'clock. According to service manual crank should be at 12 o'clock and cam at 6 o'clock.
Or if I'm wrong, tell me how to set it up to get it back where it needs to be.
They will kick and buck and shoot flames out the carb when you have them 180 out.
Short answer cam dot at 6 and crank at 12 should put #1 at tdc on the compression stroke so that is the wire/ terminal that the rotor should be pointed at.
Firing order is 1 5 6 3 4 2 7 8
distributor turns clockwise when viewed from above
when STANDING IN FRONT of the engine the odd cylinders are on the left, even ones on the right. This is not typical for GM.
This makes #1 behind the alternator and #2 behind the power steering pump.
This means 1 and 4 are both going to be at TDC with the timing mark is at 0. With the dots on the cam gear at 12 o clock this usually puts #1 on the exhaust stroke and #4 on the compression stroke so for the engine to run the distributor should be pointing at the #4 terminal / wire. This would usually make the rotor physically pointing to around the charcoal canister or radiator overflow. I say usually because the distributor does not know or care which wire is where. On the HEI caps #1 is usually the first one to the right of the connector nub and I believe on the points caps it was usually the one over the little dwell window. Why they tell us to install the timing set with both dots up does not make sense because this usually leads to us putting the distributor in pointing to #1 which is 180* out which means that someone is now without eyebrows. If you were going to install the distributor at #1 you would need to rotate the crank 1 turn which would put the cam dot at 6 o clock. I just use #4. its usually easier to get to. It does not require you to run your timing light probe wires anywhere near the fan. If you are checking for TDC / compression you can have your finger over the hole and see the marks at the same time while your buddy is bumping the starter.
Thanks for the explanation but that's not what I have.
Let me start over. Car was running bad after I took it out from winter storage. Set the timing again and changed points, plugs, and wires. Had an off idle miss in park and and bucking, shaking at around 50 MPH. Changed distributor. Same issues. Thought maybe I put it in wrong so had a helper bump the starter till I could feel compression. At that point the crank was a bit off from TDC but not much, installed TDC indicator and turned engine by hand to 0* on crank and saw the TDC indicator stick out at its max position in #1 Cylinder. Dropped distributor back in with #1 on cap lined up with rotor. #1 on cap being on right side just adjacent to opening for points adjustment. Cranked a few revolutions before starting, but started and ran as before.
Set it up the same way to remove parts. So I'm pretty sure I'm on compression stroke in #1 cylinder and crank at 0*. Cam gear indicator is at 12 o'clock position and so is crank. According to service manual, crank is OK at 12 o'clock but cam should be at 6 o'clock.
The cam "off" 180 degrees means that the cam is correctly aligned with the crank shaft. two turns of the crank for each camshaft rotation.
I believe that is a non-issue.
Greg Surfas
Greg
OK I get that, but shouldn't the TDC indicator be down at this point and then come up when the marks are correct?
Rob,
By TDC Pointer, I am assuming you mean the pointer on the timing cover and the mark on the damper. If so, again, they go around twice each time the cam goes around once, so it makes no difference as far as the engine is concerned.
Greg
Greg
No I have a TDC indicator screwed into #1 cylinder. That is at its highest point on the compression stroke, crank gear at 12 o'clock and cam gear at 12 o'clock.
OK so second time the cam and crank gears come around they're off by a tooth maybe two. So chain jumped a tooth or two. So maybe between that and a loose chain that would explain the symptoms?
Doesn't really matter at this point, I guess. We'll see what happens with new timing set and rebuilt heads.
On my 54 my bad running was due to the distributor being 180 degrees out also - it ran, but not well, see my post about it.
Phil
The only real way to check if the engine is 180 degrees out is to remove the Rocker Cover and check the operations of the Intake and Exhaust Valves in relation to the Number 1 Pistons' movement.
I think you will find that when the Number 1 Piston is at TDC, the Distributor Rotor is pointing at Number 1 Spark Plug Lead, the Intake, and Exhaust Valves will be on "Overlap", that is one is closing as the other one is opening.
Check Number 6 and you will find that the Piston will be on the top of the Compression Stroke with the Intake Valve being closed for a quarter of a turn of the crankshaft. You will find that the Rotor is pointing at the Number 6 Spark Plug Lead.
It is in these two positions of an engine's crankshaft rotation when the timing pointer on the front of the motor will be pointing at the correct mark on the Harmonic Balancer.
Bruce. >:D
Some of you have to remember we are taking about a 472/500 here, not a 429 or a Chevrolet. Its just adding to the confusion because 6 is the 3rd one in the firing order, not the 5th. On this series of Cadillac 4 is the 5th so its 1 and 4 that will both align with the timing gauge on the balancer.
The physical layout of the cylinders is flipped and the firing order is different.
Firing order is 1 5 6 3 4 2 7 8
distributor turns clockwise when viewed from above
when STANDING IN FRONT of the engine the odd cylinders are on the left, even ones on the right. This is not typical for GM.
This makes #1 behind the alternator and #2 behind the power steering pump.
I have seen timing sets that with the cam dot at 12 are putting #1 on the compression stroke but 90% of them with the dot at 12 will put #1 on the exhaust stroke.
OK I'm getting a little confused. I thought all I had to do was line up the cam gear with the the hole on the cam to the hole on the cam gear. Described as a dowl in the service manual but mine doesn't have a dowl. Anyway hole to hole bolts line up and cam gear installed. Change out crank gear and it aligns with key way. Turn both until marks line up, cam at 6 o'clock and crank at 12 o'clock. Turn engine over 2X by hand to be sure marks line up again.
Or is this not right?
Sounds correct. That should have put you so if you put the distributor in pointing to the #1 wire you should be close enough to run.
You do have the correct physical layout of the cylinders, firing order, and distributor rotation right? Obviously its easy to get confused since this engine is not typical for GM.
Yeah #1 first cylinder on passenger side of car behind alternator.
So what do you guys think? Being off 1-2 teeth and chain loose would give me the heavy vibration or whatever you want to call it at around 50 MPH? That and the questionable valve on #4 that we discussed in the other thread.
Rob,
If the cam was off by two teeth what ever poor running conditions would be apparent at all times. The bad valve, I would think is a more likely culprit.
Just to get up to speed, have you changed the timing set, or are you just looking at the original set?
If you are still thinking about installing the cam gear on the cam, I believe there is no way you can do it wrong. There is not dowel on the cam like other brands, and just two bolts hold the gear to the cam. Be sure you use the bolts that came off, as they are "special". First install the crank gear with the "dot" straight up in the 12 o'clock position, loop the cam chain around the crank gear and the cam gear (not yet installed). Then with the cam gear held in position so that the "dot" on it is in the 6 o'clock position and directly opposite the crank gear dot, rotate the camshaft so that the bolt holes in the cam line up with those in the cam gear. Bolt the gear to the cam. As you suggest, rotate the engine two turns to be sure that the dots are correctly aligned, and then install the fuel pump eccentric on the cam and the oil slinger on the crank nose.
Next time it will be the proverbial "piece of cake"
Greg Surfas
Once you get the cam timing issue resolved, I would do a compression test before putting everything back together.
Greg
No haven't put the new timing chain and gears in yet. There is on the cam shaft an unthreaded hole that the manual refers to as a "dowel". Also a hole on the cam gear itself. So line up hole to hole and the cam gear lines up with the threaded holes. No problem there.
What's the best way to remove the crank gear? I'm thinking a 2 or 3 jaw puller. Then what's the best way to install the crank gear? Lube it up good and tap it on with a block of wood and a plastic hammer? Do I need to change the crankshaft gear?
Dave
Once I get the timing chain and gears in, I need to disconnect the motor mounts to raise the engine up. Then remove the oil pan, clean it up and clean the oil pump pickup screen. When the front cover and oil pan are back on, lower the engine and bolt up the motor mounts. After that's done, the intake is coming off and the heads are getting sent out to a local machine shop. So that should take care of that valve issue.
Rob,
The crank gear should just slide off, but it might have gotten "gunked" to the crank nose, so cleaning it up with say brake cleaner and tapping it gently with a plastic or wooden hammer should enable you to slide it off. It will slide back on (don't forget the crank gear key in the crank nose keyway).
Regarding raising the engine, I believe the most effective way to remove the pan is to follow the service manual which has you dropping the (steering) idler arm off the frame and disconnecting the pitman arm to lower the steering assembly out of the way and allowing the pan to drop enough to be removed. Don't forget to mark the idler arm location exactly on the frame so you can re-install it in the exact same position.
Greg Surfas
Quote from: "Cadillac Kid" Greg Surfas 15364 on October 27, 2011, 04:47:40 PM
Rob,
The crank gear should just slide off, but it might have gotten "gunked" to the crank nose, so cleaning it up with say brake cleaner and tapping it gently with a plastic or wooden hammer should enable you to slide it off. It will slide back on (don't forget the crank gear key in the crank nose keyway).
Regarding raising the engine, I believe the most effective way to remove the pan is to follow the service manual which has you dropping the (steering) idler arm off the frame and disconnecting the pitman arm to lower the steering assembly out of the way and allowing the pan to drop enough to be removed. Don't forget to mark the idler arm location exactly on the frame so you can re-install it in the exact same position.
Greg Surfas
Greg great advice on the idler arm, if not reinstalled properly the center link parallelism is skewed and bump steer occurs, this a problem I run into in my shop on cars that have height adjustable idler arms. 60's Eldo fwd cars are the most susceptable to this.
Whenever you change any part of the Timing Set, that is the Chain, Cam Gear and Crank Gear, change them as a set. These parts are not interchangeable, especially if used.
Bruce. >:D
Pulled the intake manifold and heads last week and sent the heads to the machine shop. Just heard back from them today. They say the heads were warped but the valves and seals weren't too bad. So he thinks the low compression on #4 was probably a leaking head gasket.
If I am understanding post #20 correctly, the cam is missing the locating dowel. If you install the cam gear without this dowel, the cam gear will be able to rotate out of position on the camshaft, and that will definitely change both ignition and valve timing.
T Lewis
T,
You would have to look pretty hard to find a dowel on a 472/500 inch cadillac cam. The bolts hold the cam gear in place.
Greg Surfas
Quote from: "Cadillac Kid" Greg Surfas 15364 on December 25, 2011, 09:19:55 PM
T,
You would have to look pretty hard to find a dowel on a 472/500 inch cadillac cam. The bolts hold the cam gear in place.
Greg Surfas
I missed the part in bold below, from post #20 :P
" So line up hole to hole and the cam gear lines up with the threaded
holes. No problem there."
T Lewis