Broken Valve - VW TDI forum and Audi TDI forum

stevekarns · #1 02-28-2011, 09:37 PM

I had my timing belt strip at the crank when trying to start my car one day. When I took it apart and inspected the head I had two lifters that showed sign on impact from the valve, so I decided to replace all the valves, lifters and valve seals. None of the valves I removed showed any damage and they were straight. I got all the parts finally and lapped the valves in. The valves all had a nice even circle showing that the head was still in good shape. After getting all the timing belt and head job complete tonight I finally was to the point of starting the car. There wasn't any fuel getting to the injector pump, but after sucking fuel through the pump from the filter return line I was able to get the car started. It seemed to be running smooth at idle for about 10 minutes, until TAP TAP TAP, immediatly shut it down and started to investigate. I rolled the engine over several times and everything seemed ok, then I did a compression check and sure enough one of the cylinders had no compression!! I had to pull the Cam out again and the intake valve was BUSTED right at the keepers. The keepers and the very tip of the valve were jammed in the cap.

Can someone tell me WHY this happened? Do I need to replace all the valves again from a different supplier, Can I trust the rest of the valves?

Seatman · #2 02-28-2011, 09:45 PM

Where did you buy the parts from? I've never seen a valve break there, that's just bizzare.

stevekarns · #3 02-28-2011, 09:58 PM

I got them from a local parts store that could get them to me the next day. I didn't have much time to wait for the valves to come in, and they weren't cheap, so I thought they were good quality. Maybe they just raped me for my money. I'lll be calling them tomorrow and find out whay they will do.

I did find this on the internet,
"Breakage at the stem tip can result from excessive sideloading if the installed stem height is not right and causes rocker arm misalignment. It can also be caused by excessive valvelash that prevents the valvetrain from cushioning the valve as it closes. Another condition that may cause the tip of the stem to snap off is wear or scratches in the keeper groove(s) or coil bind (running a cam or rocker arms with too much lift)."

But I have all factory cam and and they were new valves so there shouldn't have been any prior damage.

YMZ · #4 03-01-2011, 01:16 AM

Sorry to read this !!!!

There are a lot of substandard parts out there!!! (Not that it will make you feel any better, but one of my buddies over in Guelph, Ontario - an aircraft mechanic by trade - had a local machine shop rebuild his cylinder head, and soon wound up with a grotesquely bent valve - again, missing the tip... (see http://forums.tdiclub.com/showthread.php?t=228244 )

Give Frank Irving (Franko6) a call for advice and counsel...

All the best,

Yuri

stevekarns · #5 03-01-2011, 06:56 AM

Thanks Yuri,

I'll give Frank a call once its a decent hour in MO. He seems to be the guy that knows these heads.

I'm kicking my self now for not sending the head to him before.

stevekarns · #6 03-01-2011, 05:44 PM

Well I talked to Franko6 finally and he is a Dr when when it comes to these heads. A wealth of information spewed threw the phone lines and he told me that it was bad parts. Now if I can get part of my money back from the crappy parts store I will happy. He told me how to inspect the old valves and they all measure good. I'm gonna put it all back together with the old valves and see what I get.

Thanks Frank for the information and I'll keep you guys posted.