Timing chain confusion.

[Kalums]

Ok I've read a couple of threads on here about swapping timing chains and... I'm thoroughly confused. Maybe I'm just not getting it, but are my timing marks supposed to be at the 12 and 12 position(s) OR are they supposed to be Cam mark at 6 o'clock and crank at 12 o'clock? I have found my TDC (compression stroke) and my "timing mark" and rotor are both off... And not equally. Also for a stock 350 should I get a Cloyes #C3001K or a #C3023K (or X)? I really don't want to spend hours grinding on the block. 3rd and 4th questions, suggestions on harmonic balancer (one of my current issues is because the rubber ring has deteriorated and the balancer moved) and or water pump (might as well do it while it is off already)? All I'm finding near me are Dorman parts with different sellers part #s.

Btw stock 71 350, no mods, picture is of what was supposed to be TDC... But definitely is not😩

As a side note should I re-align my distributor while I'm at this (provided it is still "off" after doing the timing set?

[Willshook]

Cam at 6, crank at 12. This will leave the engine at TDC compression #6...so remember to set to 8-12 BTDC compression #1 before dropping the distributor in. Most common reason for new engines not starting.

The C3001K is fine for a stock replacement. Double roller cams are engines making over 1 HP/CID at the wheels. Shouldn't have to grind on anything. I am a fan of putting on bolt retainers, but honestly it's not really needed. Just cheap insurance for engines that are probably going to be running for a long time. You don't need a cam button.

The Dorman stuff is fine for a stock engine. The 594-012 one is fine - the "S" for the street version just means it has some high performance features like scribed on degree marks.

Water pump is kinda up to you as a 'while I'm in there' thing...

I don't know what "re-align" means, but yes - you want to verify TDC with a piston stop, make sure the mark on the balancer and your timing tab are right, and then set the timing

[geezer#99]

Put cam at 6 and crank at 12. That’s #6 tdc compression. Rotate crank once and you’ll have #1tdc compression.
Designed that way. Easier for the engine guy to line up two dots right close togethor than try to eyeball two dots a long ways apart. Less chance of error.
If I see your timing tab/balancer mark correctly then your marks are only 4 degrees off.

[Kalums]

Originally Posted by Willshook

Cam at 6, crank at 12. This will leave the engine at TDC compression #6...so remember to set to 8-12 BTDC compression #1 before dropping the distributor in. Most common reason for new engines not starting.

The C3001K is fine for a stock replacement. Double roller cams are engines making over 1 HP/CID at the wheels. Shouldn't have to grind on anything. I am a fan of putting on bolt retainers, but honestly it's not really needed. Just cheap insurance for engines that are probably going to be running for a long time. You don't need a cam button.

The Dorman stuff is fine for a stock engine. The 594-012 one is fine - the "S" for the street version just means it has some high performance features like scribed on degree marks.

Water pump is kinda up to you as a 'while I'm in there' thing...

I don't know what "re-align" means, but yes - you want to verify TDC with a piston stop, make sure the mark on the balancer and your timing tab are right, and then set the timing

OK I understand TDC with a piston stop, that is how I found my current "TDC". When I'm at TDC on #1 cylinder my timing mark on the balancer is off by roughly 90 dgrs to the driver's side from the TDC timing tab/plate and my distributor rotor is pointing directly at the front of the engine (roughly 20 dgrs to the passenger side from pointing to #1 cylinder). So at this point my cylinder #1 is at TDC... I change the gears and chain and re-align my timing marks... Provided I don't take out the distributor, what is my next step please ? How do I get 8-12 degrees BTDC? I've never done this before. Explain it like I'm 5...(no sarcasm, seriously please be patient) and thank you.

Something I just realized and need to check in the morning... I believe if I turn the crank by hand clockwise (while standing in front of the truck) the distributor rotor turns counter clock wise if you are looking top-down at it... Isn't that an Oldsmobile "thing"? Could that be my "runs like poop" reason? Because I could tell after taking off the cap and rotor that the distributor itself was no name and shiny chrome inside ( the body, weights for the VA and springs) except for the GM icm and coil... Maybe I'm remembering wrong too... I do need sleep.

[Kalums]

Originally Posted by geezer#99

Put cam at 6 and crank at 12. That’s #6 tdc compression. Rotate crank once and you’ll have #1tdc compression.
Designed that way. Easier for the engine guy to line up two dots right close togethor than try to eyeball two dots a long ways apart. Less chance of error.
If I see your timing tab/balancer mark correctly then your marks are only 4 degrees off.

That picture was from when I first lined it up to try to find TDC, I have since used a piston stop, hand cranking both directions letting it "stop" and marking the middle... Which is about 90 degrees to the driver's side from that mark... But the caveat to that is my balancer is loose (rubber is rotten) and only takes a little force to move. I'm surprised it hasn't flown off tbh

[franken]

Line up the old cam and crank gears and forget the balancer. Then install the new gears and chain.

[geezer#99]

Post a pic of your motor.

[clay68c10]

1. Line up the gears dot to dot.
2. Replace timing set. Use blue loc-tite on cam bolts.
3. Install front cover (and oil pan if you removed it for access.)
4. Install new balancer. It is keyed and will only go on one way.
5. Check timing with a timing light and set as needed.

Or, just put a new balancer on it and check timing.
Is there a reason you're doing the chain?

[HO455]

Originally Posted by clay68c10

1. Line up the gears dot to dot.
2. Replace timing set. Use blue loc-tite on cam bolts.
3. Install front cover (and oil pan if you removed it for access.)
4. Install new balancer. It is keyed and will only go on one way.
5. Check timing with a timing light and set as needed.

Or, just put a new balancer on it and check timing.
Is there a reason you're doing the chain?

I'm going to recommend a step to clay68c10's post. Hopefully everyone is okay with that.

Step 4 1/2. After installing balancer verify the TDC mark on the balancer is lined up with the mark on the timing tab. If not then verify the timing tab is not bent or modified. If the tab is correct then the outer ring on the balancer has moved in relation to the keyway in the snout of the balancer.

Generally you check this before installing the balancer completely, just incase you have to remove it. Or you can compare your balancer to a known good balancer before installing to verify the outer ring hasn't moved.

More information on balancers in this link.

https://fluidampr.com/troubleshootin...nic-balancers/

[Kalums]

Originally Posted by clay68c10

1. Line up the gears dot to dot.
2. Replace timing set. Use blue loc-tite on cam bolts.
3. Install front cover (and oil pan if you removed it for access.)
4. Install new balancer. It is keyed and will only go on one way.
5. Check timing with a timing light and set as needed.

Or, just put a new balancer on it and check timing.
Is there a reason you're doing the chain?

Do I need to remove the pan? I've seen ALOT of tutorials that did/do... Not gonna lie I don't want to pull the engine out and I don't see any way to drop the pan otherwise.

Well when trying to time before I noticed "wiggle" in the timing mark when trying to set it. Meaning whenever I was using my light it was never exactly in the same place there was always "wiggle" of a few degrees advance or retarded. Also there is a significant delay between turning the crank manually and the rotor moving (almost 90 degrees, using an 18" breaker bar) I thought this was because of the chain, *shrugs*. I kinda feel like this truck was just never taken care of(maintained) ... If it ran it was used and if something needed done, but still ran it was ignored, kinda sad to think about it.

[Kalums]

Originally Posted by HO455

I'm going to recommend a step to clay68c10's post. Hopefully everyone is okay with that.

Step 4 1/2. After installing balancer verify the TDC mark on the balancer is lined up with the mark on the timing tab. If not then verify the timing tab is not bent or modified. If the tab is correct then the outer ring on the balancer has moved in relation to the keyway in the snout of the balancer.

Generally you check this before installing the balancer completely, just incase you have to remove it. Or you can compare your balancer to a known good balancer before installing to verify the outer ring hasn't moved.

More information on balancers in this link.

https://fluidampr.com/troubleshootin...nic-balancers/

This is an excellent idea and I will do that, thank you. Hopefully I'm able to get to this, this weekend.... But no guarantees... Because life. *shrugs*

[Kalums]

Originally Posted by geezer#99

Post a pic of your motor.

ASAP *thumbs up* any specific angles or parts? Rotor vs balancer relation?

[geezer#99]

Originally Posted by Kalums

ASAP *thumbs up* any specific angles or parts? Rotor vs balancer relation?

Just the engine bay.
From the left, the right and straight on.

[Willshook]

Good talk and raises a few questions.

If you're SURE the rubber is bad on your balancer, then replace it for sure. Can't get an accurate timing read, and dangerous as hell.

I didn't think to ask WHY you were changing the timing chain - is it because the timing was jumping around? That is a sign of timing chain slack...but if your balancer was wobbling that would be the first thing to change before you tear into the engine.

It's a pain to change the timing cover without at least dropping the front of the pan because the cover sits down on a gasket and bead on the pan. So you end up having to drop - not remove it - and then goober everything with RTV...which isn't great and sometimes doesn't last very long.

Rule of thumb on distributors: grab the vacuum advance and extend your pointer finger. Whichever way the finger points, that's the way the distributor turns. So on your SBC, if you do that you'll see that it rotates CLOCKWISE. The timing order tells you that too It's worth checking to see that the timing order is correct...not unusual to find someone at some point mixed up wires so the engine runs like crap...but since it's a Chevy, it will still run...

Note that on your timing pointer being on the wrong side...finding TDC tells you the piston is at the top of it's travel - but it's there TWICE: once on compression and once on exhaust. So you need to be sure it's on TDC COMPRESSION when installing the distributor. finding this is by putting your finger over the spark plug hole and feel the pressure - there's only pressure on the compression stroke since both valves are closed. Coming up on TDC exhaust, the exhaust valve is open so no pressure build up.

The easy way to set timing when dropping in a distributor is to set the engine to where you want the timing to be - a good point is 8-10 degrees BTDC...so we let the engine come up on compression and line up the balancer timing mark on that mark on the pointer. Then mark where #1 spark plug wire goes, and turn the distributor back about 2" or so. Drop in the distributor and see that the rotor is pretty close to the mark. You may have to bump the engine a few times to get the distributor shaft tang to drop into the oil pump...but you'll be pretty close. Then bump the engine over to the same point - 8-10 degrees BTDC and the distributor pointing right at the mark for the #1 spark plug wire. If you can turn the distributor to get close...then you're ready to start and time. If not, then pull the distributor up and turn it one tooth or the other to get it closer. You can feel the distributor gear against the cam gear to just move one tooth.

Dunno if this is too much -

[PbFut]

You can remove the timing cover without removing the pan but you need to drop the pan in the front as there is a lip the cover needs to clear past on the pan. I lossen the rear couple bolts on pan and remove forward bolts. That will give you enough room to work assuming you have good rubber gasket not stuck. It sounds like your engine is older so dropping pan is probably going to be necessary.
If rubber is bad on balancer, you must replace.
If you are getting slop on rotor, your chain and likely sprockets are bad. If the distributor is as old as the truck, replace it. Your walking timing is indication distributor is loose or the chain is just that sloppy. Go to summit and build your project on their site either in the cart or create wish list to track your budget. For general street use, summit brand parts are reasonable choice. The part will have been vetted by many customers before you so fit and quality will be decent.

[geezer#99]

I think you should invest in some reference material.
Everything we’re posting and more stuff you need to know are in a book like this.


https://www.amazon.com/How-Hotrod-Sm.../dp/0912656069

[PbFut]

Originally Posted by geezer#99

I think you should invest in some reference material.
Everything we’re posting and more stuff you need to know are in a book like this.


https://www.amazon.com/How-Hotrod-Sm.../dp/0912656069

That is the book that started it all for me. I picked up a copy at a book store in Burbank CA dedicated only to automotive publications. That would have been around 1972.

[Accelo]

If the tab is correct, then the outer ring on the balancer has moved in relation to the keyway in the snout of the balancer.

This could indeed be an issue. Another thing that will cause the same issue:

Don't forget, there are two key locations on the balancers. Early timing marks are aligned with the keyway. Later are off as they relocated the timing marks. I am unsure what year this changed. If the balancer is not original to the motor and matches the location of the timing tab you will have issues.