Author Topic: Drop a precup? 3000km's from home (Read 8942 times)

sper17 · « **on:** June 25, 2008, 08:52:48 am »

Well, so much for that head. Was on a road trip from Calgary to Nashville, and on my way home when the EGT's started rising and a rattle from the head forced me to check things out. Engine sounded rough, but I assumed it was a slightly bent valve. When I tried to start it again that stater would only turn the flywheel about 3/4 of a turn before getting jammed. Definitely a bent valve stuck open, right? The head is brand new, with about 10,000km's on it, with the bottom end being honed and re-ringed at the same time. So, I pulled the head while parked in a McDonalds parking lot.

So, what i figure happened is my merc nozzles which only ran for 400km's loosened up the precup until it finally shook loose and fell over the headgasket and into the cylinder. The head looks pretty rough, but could likely be welded and machined. The valves are fine, and don't look damaged. The block itself is slightly scared, but should just take a honing. Piston doesn't have a hole, but certainly could be cleaned up, and hopefully will be useable.

The bad news is its would cost $1600 + 3000km's of fuel to uhaul it back to canada + parts and machining. It just doesn't make sense for a $4000 car (Which I've already put $7200 into in 6 months) to get brought back. SO, anybody live in the Oklahoma City area looking for a project? I'll probably fly home and scrap the car here otherwise. Its a 94 MK3 AAZ with leather interior and everything.

jimfoo · « **Reply #1 on:** June 25, 2008, 10:14:59 am »

How long are you going to be there? I have a plan B if you want to take the chance. I have an AAZ head, may be warped, i don't know. My 3500 lb truck got very hot going up big mountain passes, but was ok on flat stretches. One pre-chamber is very loose, but I have an idea on fixing that involving my press to expand it a little, heating the head and cooling the cup to get a tight fit. It is a bare head, only guides, 8mm which I am pretty sure yours should be. I also have some good used AAZ pistons. If I feel comfortable I can get the pre-chamber fixed, I will sell the head, a piston and throw in some new spare 8mm seals for $150 + shipping. I will let you know if I don't feel comfortable with the fix, but I'm pretty sure it should work. Just let me know.

jimfoo · « **Reply #2 on:** June 25, 2008, 10:50:42 am »

Damn, it worked really good, though I had to expand it a couple times to get it to the right size.
FYI for others wanting to tighten up loose cups, what I did was found a socket that would just fit inside, pressed it in with the press, measuring the deformation with a micrometer. Then I heated the hole in the head with a torch and cooled the cup with an upside down can of spray air. I still had to whack it in fairly good with a hammer. It's not going anywhere! :twisted:

zukgod1 · « **Reply #3 on:** June 25, 2008, 11:03:23 am »

Quote from: "sper17"

The bad news is its would cost $1600 + 3000km's of fuel to uhaul it back to canada + parts and machining. It just doesn't make sense for a $4000 car (Which I've already put $7200 into in 6 months) to get brought back. SO, anybody live in the Oklahoma City area looking for a project? I'll probably fly home and scrap the car here otherwise. Its a 94 MK3 AAZ with leather interior and everything.

Damn man I'm sorry. That really sucks.

I wish you were closer to Utah, I would take it off your hands TODAY!

There has to be someone in OK on this board.

zukgod1 · « **Reply #4 on:** June 25, 2008, 11:05:29 am »

Quote from: "jimfoo"

Damn, it worked really good, though I had to expand it a couple times to get it to the right size.
FYI for others wanting to tighten up loose cups, what I did was found a socket that would just fit inside, pressed it in with the press, measuring the deformation with a micrometer. Then I heated the hole in the head with a torch and cooled the cup with an upside down can of spray air. I still had to whack it in fairly good with a hammer. It's not going anywhere! :twisted:

This is good info..

I had my head machined for larger precups then had then pressed in.
I'm paranoid as hell as to how much of a "pressing" it took now..
I would be screwed if I dropped a precup.

jimfoo · « **Reply #5 on:** June 25, 2008, 11:23:17 am »

I decided to do the others just because. They weren't loose, but weren't tight compared to the one I worked on. All are much tighter now. The #3 did have some cracks inside, but I'm sure it won't go anywhere, though at some point it probably wouldn't hurt to replace it as they will probably slowly spread with heating and cooling cycles.

jtanguay · « **Reply #6 on:** June 25, 2008, 01:09:22 pm »

sper17 i'd like to know where you bought your 'new' head. they shouldn't break like that when new... that totally sucks!

burn_your_money · « **Reply #7 on:** June 25, 2008, 07:00:13 pm »

I'll send you a head (overnight if you want) for the cost of shipping. It is complete. I'd like it back once you get home though. Or give me $50. There is a slight chance it is warped but I don't really think so.

I don't think heating the head with a torch is a good idea. You're removing any strength the aluminum had tempered into it and it is likely to warp once brought up to operating temps

sper17 · « **Reply #8 on:** June 25, 2008, 07:01:41 pm »

Thanks jimfoo, I'm considering that option for sure. My problem is I don't have all that many tools and am nervous about pulling the piston and honing the cylinder walls. I already haven't figured out how to source new head bolts and tourque wrench, but I'm sure I could.

So theres NO mk4 TDI's for under $12,000 in the area, but I've always wanted a 1.8T so I may pick up a GTI that I looked at tonight. I really got to get home and the hotel bills and car rentals add up really quick and its not worth my time to spend 1-2 weeks while a machine shop fixes my aluminum head or hones/sleeves my block.

jimfoo · « **Reply #9 on:** June 25, 2008, 07:03:25 pm »

It's hard getting a head very hot with a propane torch. I'm sure it was much hotter during normal driving.

sper17 · « **Reply #10 on:** June 25, 2008, 07:05:44 pm »

wow, a head for the price of shipping?

??

my head was one I bought from bleachedbora. I was really happy with it and it seemed to be high quality. I already talked to Aaron about it, but I'm not sure if it was a problem with the head originally, or if it was the merc nozzles. The same thing happened with dave at passenger and he said as soon as he took out the merc nozzles he could tell it was failing

jimfoo · « **Reply #11 on:** June 25, 2008, 07:06:06 pm »

I probably wouldn't worry about honing until you got home. At worst, you would have slightly lower compression and maybe use a little more oil in that one cylinder.

burn_your_money · « **Reply #12 on:** June 25, 2008, 07:27:03 pm »

Yeah I'd try and clean up the piston as best you can while it is installed and then limp home. I can mail head bolts and the head gasket with the head if you need.

RabbitJockey · « **Reply #13 on:** June 25, 2008, 07:34:54 pm »

i don't understand how that happens

jackbombay · « **Reply #14 on:** June 25, 2008, 08:05:31 pm »

Quote from: "Trev0rbr"

i don't understand how that happens

Happened to mine too, being run to hot is the problem, the precup heats up faster then the head, so it expands faster then the head, if that is repeated enough times the aluminum head eventually is pushed away from the precup and it is loose.

My TD is stock, I got it for free with the dropped precup, the previous owner drove it WOT at 45 MPH in 3rd gear for 3 miles 2 times a day for 2 years before the engine quit, 2 of the other precups are loose and all of them have pretty decent cracks in them.

Mine is an extreme case of heat, BUT it was with stock fueling, with 2-3 times as much fuel as stock like some here are running those precups are practically like ticking bombs, IMO.

I will also say that the temp gauge never moved above the normal operating position when the PO drove over the STEEP pass that was the undoing of my current TD project.