Tiny crack found between intake valves in cylinder #1

[joeeveryman87]

HAPPY 4th GUYS!!!!!!!

So im doing a lil head work on my R and found a small crack between the intake valve seats in cylinder #1(this is a boosted Dub, that threw a rod in Cylinder #1 and bent both intake valves fyi) Blue water performance says they find cracks in the aluminum head all the time between intake valve seats and thats its no biggy, VW themselves said they find cracks 90% of the time between the valve seats when they service the heads and it there SOP to ignore them, so is this somthing to be concerned with???

PICS!

[Ikey3125]

being its between the 2 intake valves, I'd say its fine, if it was between an intake and exhaust one, then I'd be worried.

[joeeveryman87]

Thanks for the input, I think I'm gonna go with it and see what happens the main thing I'm worried about is it possibly dropping a valve seat into the cylinder, since the crack in no where near a water jacket I think that's the only possible issue

[need_a_VR6]

16v heads cracked like that a lot and survived. Havent seen an r33 head like that yet, though.

[joeeveryman87]

Well I'll be starting it up in a few weeks with the cracked head I will most def let the forum know of the out come, still between now and then any insight on the matter will be greatly appreciated, thanks again guys!!

[joeeveryman87]

Btw does anyone know if the seats in the R head are pressed of machined in?? Curious for structural integrity reasons with the crack.....if it even makes a difference either way idk just curious

[joeeveryman87]

Bump!

[joeeveryman87]

So the head is all bolted on nice and tight(not running yet, waiting on the ECM to get back) i did a compression check on my cylinders and it was as follows......

Cylinder
-#1 63psi
-#2 120psi
-#3 122psi
-#4 120psi
-#5 122psi
-#6 121psi

Cylinder #1(or rather combustion chamber #1) was the chamber that got a little beat up and had the tiny crack in it, so this cant be just a mere coincidence. So a couple questions are in order.....

1) Against my better judgement i never replaced the Valve seats in that chamber where it cracked and bent the valves, so would you think the air is leaking through the crack? or through the intake valves not properly sitting on their seats? (im thinking the latter, because of how small the crack is)

2) I know it will still run with 5good cylinders, but will 60psi cause wild misfires in #1, and potential worse problems? so what im getting at is can i drive it till winter comes along, till i pull the head AGAIN!!! lol

[need_a_VR6]

Throw some oil in and retest just to rule out ring seal.

[joeeveryman87]

Throw some oil in and retest just to rule out ring seal.

I was gonna do that, but it ran fine befor the head swap so i didnt think it would be the piston rings, your right though i will rule it out, and might as well do a leak down test to make sure its not a freak kink in the brand new head gasket i put on aswell.......unfortunately since the crack is on the intake side a leak down wont tell me if its leaking though the valves not seating or the crack....and i was told to leave the crack alone at all cost

[joeeveryman87]

Ok so retested them all, and did a wet test on the problematic #1 chamber......

#1-Dry(75psi) Wet(95-100psi)
#2-Dry(110psi)
#3-Dry(95psi)
#4-Dry(120psi)
#5-Dry(120psi)
#6-Dry(120psi)

what is the average tolerance in psi between wet and dry test, befor you consider a ring failure?

Also this engine has 113,000miles on her......

[need_a_VR6]

At this point, do a leakdown in cyl 1 and listen to where the air is escaping.

[vwmaniac16vr6]

Well was cylinder one replaced but not the others? If that is the case then numbers are off because rings are not seated yet.

[joeeveryman87]

started the car up and it ran like garbage compression checks found nothing was sealing up. Pulled the head BACK off!!!! brought it to a different machine shop and found that the previous shop gave it a horrible valve job, never the less, new shop re-did the valve job, did a vacuum and pressure test, everything was holding. Put the head BACK on, hooked everything up(except water, just to make sure it ran better) started up beautifully! hooked up water and all the other lil things, and started her up and let it idle to temp, besides a few lil blips it idles really good, so i brought it around the block to find that under a load it has NO power and hesitates extremely bad, aswell as some weird wine/grind noise starting around 2000rpms and up getting louder as you speed up, but sitting in nuetral the noise never comes when you rev it(this being the least of my concerns considering the power loss) then i get back home and pull these codes off the ECM in this order......

-P0300(Random/Multiple Cylinder Misfire Detected)
-P1050(VVT Control Circuit Bank 1 Electrical Malfunction)
-P0304(Cyl. 4 misfire)
-P1364(Cyl. 4 ignition circuit Open Circuit)
-P0204(Cyl. 4 Injector Circuit Fault in electrical circuit)


Could the P1050 be an oil passage being blocked somewhere to the exaust cam adjusting gear?

Theres seemingly alot going on with cylinder 4, but to be fair i new it was firing when i got back from around the block, so i did a compression check across the board and all cylinders were in limit and the were all getting spark so i figured it was an injector issue, so while it was running i pulled the injector plug wire and tested it with a node light to make sure it was getting power(it was) but because i pulled that plug while it was running thats more than likely the reason for the last two codes. I pulled the whole rail off and watched all the injectors spray(including Cyl. 4) so its not an injector problem.....so WHY is #4 doing little to nothing??(i swapped plugs and coil packs to so rule them out)

Just FYI changes.......

-Battery relocate to the back
-SAI Delete(pysical and software)
-Extended all the ignition coil wires(going to thoroughly check them, could a broken wire somewhere cause it to spark incorrectly?)

Engine sound @ idle
http://www.youtube.com/watch?v=uGPYp...ature=youtu.be



i did a new compression check with new valve job, went as follows......

-Cylinder-

#1-100psi
#2-100psi
#3-100psi
#4-105psi
#5-100psi
#6-100psi

oddly enough cylinder 4(which is having most the issues) has the highest PSI wtf???

you think with such consistant compression numbers, this pretty much has to be a timing issue?

awaiting your thoughts.......

[need_a_VR6]

I would double check the coil rewire and make sure the injector clips are seated well.