2010 DIY head gasket repair help in Madison, WI

I started a response in the other thread you posted this to (the GasketMasters video thread), but then held off, mainly cus I'm out of my depth. I haven't got my head around it, have no personal experience with this, but anyways, for what it's worth, here's what I typed there:

My head's swimming. A few thoughts:

1. If you put new paint marks on the chain, definitely use a distinct color, something that won't be confused with existing paint marks.

2. TDC on piston #1 can be determined by just putting a long dowel through the spark plug hole, turning the crankshaft till the dowels pushed the highest. Worth noting: there's a compression and and exhaust TDC.

3. Step back, think it through: how would they do the initial assembly at the factory.

My 2 cents: you need the two cams and crankshaft at a certain point in rotation, and the chain links positioned just right on all the sprockets. I don't think it should be necessary to reinstall the tensioner device, timing chain cover and balancer (aka unused belt pulley), in order to accomplish this.

I would watch both GM videos again, the older one in particular. And have a read through the Repair Manual excerpt attached above. And just think on it. It can't be that hard, to get all the sprockets and chain links sync'd.

 

I believe you are good to go.
I would take the slack out of the chain after everything is set, before putting the tensioner in.
If the camshafts are on their marks, and the crank is on it's mark, and the chain marks are
where they should on the cams, you should be good.
Putting white paint on the crank and cams so you can easily see them is good.

TDC actually means: Top Dead Center, on the COMPRESSION stroke, NOT the exhaust.
The next round is not actually considered TDC because it's the EXHAUST stroke.
That's how it was explained to me in Mercedes school, and from other experience GOOD mechanics
and technicians.

 

Eric the Car Guy goes into some detail in this video, re determining compression TDC vs exhaust TDC. Something about there's more air blowing out of the spark plug hose on compression vs exhaust stroke. This link is at the point he starts talking about that:

 

TDC is for the COMPRESSION stroke.
IF, for some reason, someone for some reason was talking about when the piston is at the
very top for the exhaust stroke, they would, just say that....

 

I've never seen that said about 'TDC' before.

Granted, "TDC of compression stroke" is nearly always the one we're looking for ... but that's why we're often careful to say "TDC of compression stroke".

The Repair Manual seems to consistently say "SET NO. 1 CYLINDER TO TDC/COMPRESSION".

 

If you just say to put the "engine at TDC," that very consistently and undoubtedly means that the piston in the #1 cylinder is at its highest point on its compression stroke. Just a simple definition.

So these all mean the same thing:

• engine at TDC
• cylinder #1 at TDC
• cylinder #1 at TDC on its compression stroke
• cylinder #1 at TDC with all valves closed

Go ahead and google "engine at TDC" to see how clear and unambiguously understood that is.

Of course the same thing or any other configuration can be similarly clearly specified using more words.

On the ECG video ^, interesting... The compression stroke occurs when all (typically 2 intake and 2 exhaust) valves are closed. On that, with nowhere else for the air to go as the piston comes up, there would be a little puff coming out of the spark plug hole to blow out the paper towel. So you can wait for that, and then know you're on the compression stroke, take it to the top, and know you're at TDC. On the other hand, the exhaust stroke has the 2 exhaust valves open, so when the piston comes up on that stroke, the air has another exit and the paper towel may remain where it is.

Speaking of exhaust valves, did anyone else notice how smoke came out of Eric's ears there at 8:29 when he sighed?

Another way to tell whether all valves are closed or some are open is to use a compressed air nozzle to just blast some air in there through the spark plug hole. The sound will be distinctively different when the valves are all closed. Of course that is just a rough check, and you need to use the screwdriver method or checking timing marks to get exactly TDC.

 

It just occurs to me: if the cams aren't connected to the chain, all bets are off?

 

Oddly enough, that'e exactly what I did to see how consistently careful writers say "TDC of compression stroke."

 

I take it you got it going? I'm happy for you!!!
Manufacturers make there money on selling product, not repairing it.
So they marks are probably just there for putting it together when it's new.
After that, it doesn't matter I guess. Some do better than others.

First time I did a timing chain I just KNEW I'd screw it up and ruin the engine.
But I didn't. And each time it got easier as I learned little tricks to doing it.
Pretty nervous first time I did a timing belt. But it's the same thing.

Parts like a head gasket, vital to the engine, I buy a better product.
Any other gasket that is easy to get to isn't so bad.

"TDC is just plain TDC before you put the chain on." Because the valves aren't involved yet.
Once they are, it means on the compression stroke.

I don't remember, did you install an OCC, and a new pcv valve?
I know you cleaned the cooler and related parts.

Please keep us up to date on how it's running.

 

I know it’s an old thread but wanted to add.

#1 In reference to this comment yes when the timing chain is removed it doesn’t matter TDC is TDC. Also DO NOT SPIN YOUR ENGINE WITH THE TIMING CHAIN REMOVED AND THE CAMS STILL INSTALLED.
#2 On these particular engines when the #1 cylinder is at TDC relative piston position irregardless of exhaust/compression stroke the crankshaft key way is at the 12 o’clock position.
#3 When the engine is at TDC on the #1 cylinders compression stroke the cam lobes of the #1 cylinder when viewed from the front of the motor face diagonally up and towards the center of the head at roughly 1:30 position on the exhaust cam and 10:30 on the intake.
#4 Once you’re putting the timing chain on you only need to have the cams close if you look there is a hexagonal portion of the cam shaft in between the timing gears and the first set of lobes I normally put a wrench on the intake cam, lay the chain on the exhaust sprocket and rotate the intake cam counterclockwise slightly, put the chain on the marks and rotate back clockwise to take up the slack. A valve spring pushing up on a rocker arm will keep tension against a cam lobe and keep the chain tight between the cams so you don’t have to fool with them. At that point you can then put the chain on the crank sprocket. Since the tensioner is out there is plenty of slack to work with, just take the sprocket off the crankshaft align to the timing marks on the chain and reinstall on the shaft. You can rotate the sprocket however you need to line up with the key just once it’s engaged with the chain make sure you don’t jump a tooth.

Hope this helps someone. It’s really not that complicated but I understand the fear of the unknown. Plus you don’t get a do over after you’ve spent multiple hours putting the engine back together only to have a piston drive a valve back into your head.

 

I've bookmarked, and copy/pasted the above, will try to get to it when the caffeine's reached my brain cells.

 

||| The Crank pulley stays My friend look closely at schematic|||

 

@ttou68
I see this video is now marked as "private" on YouTube. Anyone know how to access it anymore?

 

I know this is an old post, but, just so someone doesn't dig it up and think they can leave this part off.
The crank pulley is also a harmonic balancer. Regardless of what else internally that is held together by the assembly, or the fact that on a Prius there is no belt, the balancer is there to counter internal vibrations and torsional stress on the crankshaft. Leaving it off would result in all sorts of issues, and possibly a broken crankshaft.

 

Hope your rebuild went well. I also live in Madison.

 

How can I watch this video? Thank you I am having head gasket issues as well.