# Valve and head failure - Do you think I can hone these cylinder scratches in the car w/ a drill motor hone?



## totheMax (Jun 11, 2008)

Had a valve and major head failure ... one piston got jacked up too 

Do you think I can hone these cylinder scratches in the car w/ a drill motor hone? 

bunch more photos of the carnage here 

I cannot really feel them with the tip of the finger but if I run my nail across them I can... I really wanna hone thees in the car and just change the rings and the one destroyed piston... would like some thoughts from experienced machinists . thx for all your help and thoughts 

I wanna do the repairs in the car but I don't wanna burn a bunch of oil.. .I can take it like 1Q/ 2000 Mi but not 1 Q/500MI. This is a tack car and I change oil after every 2nd track day anyway so I don't care if it burns a little oil. 















































































Seems like a good news bad news scenario... 

Here's what I found... 

1- the bottom of the head at cylinder 4 appears totally toast... not sure if anybody can repair it... 


2- the piston 4 is definitely toast but there does not appear to be any major scratches on the cylinder wall in any of the cylinders.... (including 4) there is lifter shrapnel dust in all the cylinders but they do not appear to have scratched anything. The rods do not appear bent because all the pistons appear at the same height and the engine turns well. 


3- turbo seems fine and did not appear to have swallowed any shrapnel. 


Looking for comments on my tentative next steps: 

1- Get a new ported head, order new cam and one new ASV piston. 

2- Get all 4 piston valve pockets cut deeper & balance all 4 assemblies before putting back in. 

3- remove oil pan and inspect bearings, rods etc 

4- clean everything well 

5- remove all pistons and light hone all cylinders 4 

6- install new piston and check clearances on all 4 pistons 

7 - Put head back on 

8- re-assemble rest of the car and stop drinking. 

I really would like to do steps 3 to 8 with the block in the car. 

Comments.. suggestions? 

tnx


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## mechsoldier (Aug 14, 2004)

No way in hell. I'm an ASE Master Tech (well until last December when I let my certs lapse because nobody cares) and I have a degree in machining (and work night shifts in a machine shop making parts out of Titanium for Boeing). So there's my background.

Anyway, that thing is toast. Honing removes small amounts of metal, take into consideration the crosshatching which is still visible on the cylinder walls (and will remain there for a couple hundred thousand miles). So honing that cylinder isn't going to take the scoring out of the cylinders (without increasing the bore size). If you can see it, it's probably .010 or more deep which would require larger pistons for sure. More or less find a new engine.

That looks like a MK3/early MK4 TDI....Is that what that is?


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## totheMax (Jun 11, 2008)

mechsoldier said:


> No way in hell. I'm an ASE Master Tech (well until last December when I let my certs lapse because nobody cares) and I have a degree in machining (and work night shifts in a machine shop making parts out of Titanium for Boeing). So there's my background.
> 
> Anyway, that thing is toast. Honing removes small amounts of metal, take into consideration the crosshatching which is still visible on the cylinder walls (and will remain there for a couple hundred thousand miles). So honing that cylinder isn't going to take the scoring out of the cylinders (without increasing the bore size). If you can see it, it's probably .010 or more deep which would require larger pistons for sure. More or less find a new engine.
> 
> That looks like a MK3/early MK4 TDI....Is that what that is?


Yes MK4 TDI ALH.

Tnx for your reply... I will keep you posted what I end up doing..

I Just send my head out for analysis and a spare one to be bored and rebuilt.

sending my pistons to have the valve pockets cut down about .040 ... and re-balance with the one replacement piston. hoping to increase valve / piston clearance.

As far as the block, I am still trying to decide what to do. I know the right thing to do is to send out to be rebored and oversized but I might try the band aid solution of honing in place first and see what it does to the scratches before pulling out the block. I really don't care if it burns a bit of oil as this is a track car and I change the oil after every track day so I really don't give a F_ck if it burns oil... 

I guess I'll what it looks like after I try the honing in place and can always take the block out to oversize if the cheaper solution does not work ... major PITA for me to do in my home garage though + don't feel like spending a butch more $ on machining & new pistons


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## mechsoldier (Aug 14, 2004)

For a race car it might be ok. But it won't last 100,000 miles.


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## totheMax (Jun 11, 2008)

mechsoldier said:


> For a race car it might be ok. But it won't last 100,000 miles.


Yes... I concur ... but I'll be dead before that engine reaches 100k miles 

I think the repair came out pretty good.. .what do you think?










That is one *amazing* tool:





























This the cylinder which had all the damage


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## mechsoldier (Aug 14, 2004)

Hmm, I stand corrected maybe. They say you can feel about a 10th with your finger and that's what I kind of feel is normal. Honing normally takes about 10 - 15 seconds in each bore, so hopefully that wasn't a 10 minute hone or anything. I have one of those hones too, they are the only thing I'll ever use again. Way way better than the old school straight stone hone.

The crosshatching looks pretty good. You probably don't have the tools but it'd be interesting to put a dial bore indicator and check to see the bore size.


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## totheMax (Jun 11, 2008)

Hey tnx for the compliment partner, not bad for a rookie. 

I did about 500 rpm and 14 seconds clockwise and then did another 14 seconds counterclockwise. Went up and down once per second. So total of about 28 seconds per cylinder. That flex hone is amazing compared to the stone hone.

I don't have a dial bore indicator but I'm tempted to go buy a cheap one at Harbor freight before putting my pistons in. I will buy a dial gauge to measure the deck clearance of each piston ...




mechsoldier said:


> Hmm, I stand corrected maybe. They say you can feel about a 10th with your finger and that's what I kind of feel is normal. Honing normally takes about 10 - 15 seconds in each bore, so hopefully that wasn't a 10 minute hone or anything. I have one of those hones too, they are the only thing I'll ever use again. Way way better than the old school straight stone hone.
> 
> The crosshatching looks pretty good. You probably don't have the tools but it'd be interesting to put a dial bore indicator and check to see the bore size.


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## LT1M21Stingray (Sep 14, 2006)

totheMax said:


> I don't have a dial bore indicator but I'm tempted to go buy a cheap one at Harbor freight before putting my pistons in.


Do it. :thumbup:


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## totheMax (Jun 11, 2008)

Mtl-Marc said:


> Do it. :thumbup:


Merci MARC, J'en ai achete une aujourd'hui de Amazon.com...


This is such a frickin cool photo ... .where/ when and for what occasion did you take this shot?


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## totheMax (Jun 11, 2008)

UPDATE...

Today I picked up the pistons/rod assemblies from the machinist...

- cut down the valve pockets about 40 mil deeper
- Measured and checked all the rods - all true
- installed the new piston NO. 4 on the rod and balanced that assembly to match the other 3.
-checked all 4 assembles
-new rings & new bearings

Also, I was relieved to hear what he had to say when he looked at the photos of my garaged honed cylinders and the remaining (small) scratches.... He said something like... just put the pistons in there and run it... I have seen much worst scratches on some race engines cylinder wall which worked fine.

Will put them in this weekend if my bore gauge comes in.

Can you find Elmo?


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## totheMax (Jun 11, 2008)

Pistons & new rings went back in


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## totheMax (Jun 11, 2008)

Got my head back & put the car back together... pulls harder than a MOFO... does not take oil or any blue smoke...

I think my guy did a better job at porting this head than the other b/c it seems to pull wayyy harder... maybe also I have more fuel because the new Race 520 nozzles were set to MAX fuel..

Anyway tnx for your help.. just wanted to tell you that it worked GREAT and there does not seem to be any adverse effect from these smalls scratches so far..










Still using 3 hole though to lower compression


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## peter139 (May 4, 2005)

nice done.

i saw you old timing belt in the photshoot. Did you find the cause of all the damage?


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## totheMax (Jun 11, 2008)

peter139 said:


> nice done.
> 
> i saw you old timing belt in the photshoot. Did you find the cause of all the damage?



Good catch,

I am thinking it skipped a few teeth. Then the valve contact and then the busted up lifter...


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