Fresh head install. Possible mistake

[pauleyman]

I was going through a mental checklist this morning and I may have made a big mistake. I torqued the head down last night and that's where I stopped for the day. Cams are in it and lifters are bled down. Yesterday's repairs included deburring the spots on the pistons where the valves hit. After I was done cyl 2 and 3 were at tdc. The cams are dowels up but I don't have a tool installed so they're at their natural position of exhaust slightly retarded and Intake slightly advanced. I would usually put pistons down bore some and then realign during timing belt install but I forgot this step. Very curious if I could have bent the valves on 2 and 3. Found one post where @1cleangsx mentioned he did just this. I'm gonna pull the cams and check out 2 and 3. Any thoughts are appreciated.

 

[1990TSIAWDTALON]

If the lifters were "soft", I think you dodged a bullet. I would do the same thing you are for peace of mind. I dont think you hurt anything. Put a straightedge across the top of the valve stems to check if they are all the same.

 

[1cleangsx]

In my case I had timed up the bottom end, had cylinders 1 and 4 at tdc, but when I put the head on it wouldn’t seat 100% flush until I torqued it down, such a bonehead mistake , luckily it only bent 2 intake valves on cyl #1 so it was $30 in intake valves and maybe $100 or so at the machine shop, if your head seated flush before you torqued it down your probably fine

 

[99dsmer4g63]

I would do a leak down test on the cylinders in question after removing the cams personally.

Hopefully you’ve gotten lucky. I always bolt my cams in after torquing the head down and while all the pistons are all even in their bores. Bolt the cams in and then slowly being 1&4 up to TDC. Just the way I like to do it to ensure this never happens, it happens more than you think.

-Daniel

 

[curt-s]

You could unbolt the cam caps, loosen them up to release tension on valves, then throw down a light into the cylinder via the spark plug holes and look at each port through intake or exhaust. With nothing pushing down the valves you shouldnt see light
But youll need strong enough light, maybe from a borescope

In my case I had timed up the bottom end, had cylinders 1 and 4 at tdc, but when I put the head on it wouldn’t seat 100% flush until I torqued it down, such a bonehead mistake , luckily it only bent 2 intake valves on cyl #1 so it was $30 in intake valves and maybe $100 or so at the machine shop, if your head seated flush before you torqued it down your probably fine

I've always had 1&4 at TDC (or near) when my cams went in after bolting the head down. Cams go in next straight up. Crank gets rotated to TDC then cam sprockets aligned with 17mm and slip the belt & zip tie it.
With crank at TDC and cams dowel up you have a fair enough number of degrees of cam rotation before you hit piston to valve...
In fact I would advance exhaust one tooth just to counteract the tensioner work as Ive never used the cam lock tool.

I don't see how you could hit valve to piston when cams are dowel up and crank is tdc. They don't open nearly enough

 

[1cleangsx]

I don’t remember the exact position of the cam dowels when I put the head on, maybe the s3 cam size had something to do with it?

It may have happened after I torqued the head down, and then set the cams doweled up to insert the plastic piece between the gears for the belt, I wasn’t aware initially but my builder told me over the phone it’s possible to bend a valve by hand when timing it up

 

[pauleyman]

You could unbolt the cam caps, loosen them up to release tension on valves, then throw down a light into the cylinder via the spark plug holes and look at each port through intake or exhaust. With nothing pushing down the valves you shouldnt see light
But youll need strong enough light, maybe from a borescope

I've always had 1&4 at TDC (or near) when my cams went in after bolting the head down. Cams go in next straight up. Crank gets rotated to TDC then cam sprockets aligned with 17mm and slip the belt & zip tie it.
With crank at TDC and cams dowel up you have a fair enough number of degrees of cam rotation before you hit piston to valve...
In fact I would advance exhaust one tooth just to counteract the tensioner work as Ive never used the cam lock tool.

I don't see how you could hit valve to piston when cams are dowel up and crank is tdc. They don't open nearly enough

It wasn't at tdc. 2 and 3 were. If it were 1 and 4 and said then yes it would be fine. I forgot to move the pistons.

 

[pauleyman]

It's confirmed. Cams out I have air leakage past the valves. At the very least number 2 exhaust. At least I caught it before the whole thing was buttoned up.
Very embarrassing. I'll know the whole extent once the machinist gets it. 1 and 4 were at bdc so no issues there. Makes me want to do as others have suggested and only bolt head down with no cams. Guess it really doesn't matter if you remember to move the freaking pistons.

 

[curt-s]

It wasn't at tdc. 2 and 3 were. If it were 1 and 4 and said then yes it would be fine. I forgot to move the pistons.

Sorry the tdc part was meant for @1cleangsx, the only advice I had for you specifically was the light show

It's one for those things that if you don't do it constantly it's easy to forget order of operations.

 

[pauleyman]

Head is off and I already talked to machinist. The pistons have no witness marks. Guess it doesn't matter. It leaks and that's that.

 

[pauleyman]

You guys chew on this. I filled the #2 exhaust ports with alcohol and left it for 10 min. Nothing. I left it with the machinist anyway and will have it leak tested. With #2 and #3 at TDC with dowels up that's 90 degrees off on the cams. Thats bent valves territory. Maybe I'm just paranoid.

 

[danl]

The only thing I can add is that cometic says you can reuse the headgasket if you never fired up the engine. I would be comfortable saying that is true of all MLS. Maybe that saves you some money. If you want to replace it anyhow I’ll send you my shipping address to “dispose” of it in an environmentally respectful manner.

 

[pauleyman]

The only thing I can add is that cometic says you can reuse the headgasket if you never fired up the engine. I would be comfortable saying that is true of all MLS. Maybe that saves you some money. If you want to replace it anyhow I’ll send you my shipping address to “dispose” of it in an environmentally respectful manner.

Well it's a composite fel pro. It's so perfect I thought about reusing it but for 30$ I guess I have a fel pro wall decoration.

 

[danl]

Well it's a composite fel pro. It's so perfect I thought about reusing it but for 30$ I guess I have a fel pro wall decoration.

Sadly I think you are right. The way a composite crushes I doubt they are reusable. Next time buy a mls so you can have me recycle it for you.

The head work will probably be 2 valves and lapping them in. So, very cheap.

 

[1990TSIAWDTALON]

I am puzzled at how the head holds alcohol, a very thin fluid.

 

[pauleyman]

I am puzzled at how the head holds alcohol, a very thin fluid.

At this point I'm more curious than I am mad. I'll know soon enough I guess.

 

[1cleangsx]

A simple compression test would’ve ruled it out, when I tried to start the car after the fact the car wouldn’t idle on its own, 6 or 7 cranking attempts we said screw it . Fun Fact after cylinder #1 not firing the oil I drained looked like orange juice with the ethanol in it

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Here’s the pic my machinist sent me.

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This cylinder had 0 compression.

After fixing the cylinder head the car sounded like this

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[pauleyman]

Dead end. All pressure tests passed. All I can think of is a tiny piece of grit or sand. I didn't have a proper leakdown tester as apparently mine is broken. I was able to add air but I couldn't measure it. I'll fix that soon enough. The good news, the machinist said "no charge". So I lost a week, a set of bolts, a head gasket and my pride. Maybe I'll add some more crap to the tumbler and let it rip. I have an extra week and a fresh bottle of green pyramids.

 

[pauleyman]

I reassembled the head today. The problem had to be some small piece of grit etc. I put the cams back in dowels up. With bled lifters numbers 2 and 3 barely have open valves. I'm thinking like .020 if that. I would be surprised if they hit anything given we have valve reliefs and even if they did the lifter has some room to give. Doesn't matter at this point. The pressure tests passed. Pressing forward and this thread is closed. Just an FYI I think I would reuse this gasket if needed. Nothing stayed behind and it looks new. Yes it's crushed but you have to look hard to tell it from a new gasket.