Timing chain help

[Racer X]

22 minutes ago, RMin280 said:

@Reptoid Overlords The previous owner of my z put on an aftermarket harmonic dampener, so there are marks on it but not sure which one to use. It has 5 grooves I believe and two red paint marker marks. I can try and keep turning it over to see if it lines up but I was spinning it over quite a bit and couldn't get any of them to line up. The closest they got was the first mark or groove almost lined up with the bottom of the plate that has the degrees marked on it. I'll try and use a screw driver but how would I know if it's exactly tdc? If I'm a little off it can move the notch and not give a good representation of if I need to move my cam.

Show us a picture of the damper and the timing marks.

As for knowing where TDC is, the best way is to use a dial indicator and measure the top of the #1 piston. Trouble is, that pesky cylinder head is in the way.

A trick is to use some clothesline cord, or sash cord, feed it into the #1 cylinder through the spark plug hole (do this when the piston is close to TDC on the compression stroke so the valves are closed, about an inch or so - you can shine a light into the hole and see the top of the piston), until you have a few inches of cord in, then rotate the crank until the cord compresses and you cannot turn the crank further.

Mark the damper coincident with the zero on the timing scale on the front cover, with an art pencil of contrasting color.

Back off the piston by turning the crank the opposite direction just enough to get the cord out, then rotate th crank up to, and just past TDC about as far as it was ahead when you shoved the cord in the first time. Then feed the same amount of cord in again, and move the crank so the piston goes back toward TDC, again until it stops.

Again, make a mark on the damper, coincident with the pointer.

Interpolate TDC on the damper, if it isn't correctly marked.

Not as accurate as the dial indicator method, but it should get you pretty close, and confirm if your damper has spun or not.

 

 

 

Edited October 14, 2022 by Racer X

[Patcon]

I agree, double check there are no exhaust leaks

[Racer X]

11 hours ago, siteunseen said:

Shade "woody shrub" way is push the handle of a big screwdriver down between the chain. 

I see what you did there. 😁

[Racer X]

2 hours ago, Reptoid Overlords said:

Our '92 Camry has a timing belt service interval of 60.000 miles.  Miserable job too. 

We had a '92 Camry also. Mrs. Racer put several hundred thousand miles on it. I did all the maintenance except the timing belt. I despise front wheel drive cars, and despise working on them even more.

But.

A longtime friend is also a mechanic, and has worked at just about every Toyota dealership in the Puget Sound region, so he is well versed in them. After 25 years of beating his brains out doing the flat rate game he opened up a shop of his own. I asked if he wanted a timing belt job. Knowing we had the Camry, he eagerly agreed, $200, plus the belt.

I asked if I needed to schedule it and drop the car off. He said just stop by early on a Saturday and he'd do it while I waited. I asked how long it would take, and he proudly proclaimed 20 minutes.

Sure enough, I arrived early Saturday, pulled the car in, he went to work, and 20 minutes later he was starting the car to back it out the door.

He changed the belt three more times before we gave the car to the son and his wife.

 

 

[Captain Obvious]

12 hours ago, siteunseen said:

Shade "woody shrub" way

46 minutes ago, Racer X said:

I see what you did there. 😁

Hahaha!!!!!   

[Captain Obvious]

4 hours ago, RMin280 said:

 I’m having difficulty setting it to tdc. I can get both valves on cylinder 1 to be closed and have the bright link on #2

Ignore the bright links. They only properly line up every eleven revolutions of the cam (every 22 rotations of the crank).

[RMin280]

I’ll take a picture of the dampener tomorrow to show y’all. I’ll try the string method to find tdc. This is probably a dumb question but how would I determine if there was an exhaust leak?

[Racer X]

5 hours ago, RMin280 said:

I’ll take a picture of the dampener tomorrow to show y’all. I’ll try the string method to find tdc. This is probably a dumb question but how would I determine if there was an exhaust leak?

Use cord, not string. Sash cord, or clothesline, in a diameter just smaller than the diameter of the spark plug hole, about 1/4”. 
 

You look for visual signs of exhaust leaks, i.e. carbon coming out around connections and mating surfaces. With the engine running, listen. If you hear a leak, it can be pinpointed using a length of 1/2” heater hose (I have a piece hanging from the handle on my toolbox just for listening for exhaust and intake leaks, and other pesky noises).

[RMin280]

Here’s a pic of the dampener.

As for exhaust leaks, I didn’t see any carbon around the manifold but I’ll use a hose to see in a little bit.

[Zed Head]

Can you take another picture and pan out to include the timing tab on the left.?  Never seen that many points.  You need to decide which one you want to use as zero.

Grab on to that damper (an engineering/physics word, not dampener) and yank it around and back and forth.  See if it's loose.  It's been known the that the wrong combination of bolt and washer can leaver the damper loose on the crankshaft.  Plus the PO replaced it for a reason, there might be damage under there.  That bolt head looks pretty beat up.

[RMin280]

Here’s a better pic for you. As for why the po put it on, the car doesn’t have ac and was and will be raced somewhat frequently so having a harmonic damper helps. It doesn’t matter too much on an in-line 6 but still, and less rotational mass. 

I tried turning the damper by hand and it moved a little but the bolt was also moving so I think it’s tight but I could be wrong. I didn’t get around to checking for exhaust leaks so I’ll try and do that tomorrow if I have the time.

[Zed Head]

Just realized that that is a 280ZX timing mark tab.  You never said what you're working on, you just kind of jumped in to valve lash ash and noises and have "280" in your user name.  Looks like a 280ZX engine.

Anyway that's an aftermarket damper with odd markings.  Might be a Powerforce Performance Professional Products "Harmonic Damper"  like the one MSA sells.  You have some mysteries ahead of you.  Who knows what's in there.

Read the notes about the timing marks.  Might as well just start from scratch with RacerX's advice.

p.s. you always need a damper.  Somebody just replaced your factory damper with aftermarket.  But you could go back to a stock ZX damper if you wanted to make life easier.  Seems like the pulley diameter is smaller with that "performance" unit which will make your alternator and water pump spin slower.  Both bad for 280ZX and 280ZX engines.

https://www.thezstore.com/product/5074/performance-harmonic-damper-70-83-zzx