Head gasket failure - what else should I replace?

[jmj996]

I also just had a head gasket failure with a spectacular smoke screen while I was on the track yesterday. I was not running hot, and I don't think there's any serious damage (don't even see coolant on the dipstick or in the oil fill cap). 1986 944 Turbo, 138k miles. Here's a summary of engine-related maintenance done to it:
Head gasket job and valves were redone at 65k miles due to a timing belt failure. Timing belt was just replaced at 129k miles and retensioned at 131k.
Front Engine Seals at 88k miles
New intake manifold gasket at 135k miles
New turbocharger at 130,xxx miles
Oil cooler resealed and P/S pump replaced at 132,xxx miles.

No mention of a water pump replacement in the maintenance history, and I don't think they replaced the timing belt rollers when they replaced the belt, so I guess this is a good time to do those. Anything else you recommend? I will not be seriously modding this engine for big HP gains beyond upgrading to a K26/8 sometime in the future if/when the K26/6 goes out - I'd like to do more, but after reading months of posts it looks like a neverending problem chasing the next point of failure, and that won't be much fun. That said, do you think I need to replace the head studs or any other main hardware?

Also, the head gasket replacement kit I'm looking at comes in two versions - standard/stock and widefire. Any significant advantage to the widefire on a mostly stock engine?

[ryan951s]

Well, as a guy who is currently replacing his headgasket after one of those spectacular clouds of white smoke at his last track day (see my other post), I can tell you the "extra" things I've been looking at:

- check your coolant hoses very carefully, and replace any that are marginal. Especially the ones running from the heater core to the head, the only way to get to those is when the intake is off, and they're pretty cheap.
- same thing with vacuum lines ... check and replace anything that is marginal.
- I would personally do your water pump, belts and rollers while it's apart.
- oil cooler seals if they're leaking. Mine aren't, so not touching them.
- check for any obvious oil leaks while it's apart. My turbo (K27-8) was slinging oil over the front of the motor and the seals on the Oil/Air Seperator was leaking over the rear of the motor, so I spent some time cleaning. New o-rings for the OAS were only a few bucks, available through Porsche.
- new plugs, cap, rotor, and possibly wires
- I found if you replace the exhaust header studs with bolts, it's a lot easier to get the headers on/off (although some may boo me for replacing studs with bolts)
- if you're oil pan is leaking and you want to go crazy, you could drop the cross-over pipe and crossmember to change the pan gasket. If you go that far, might as well change the rod bearings as well (I did it last year, very easy job), and check the motor mounts (one of mine came out in 2 pieces.)
- you SURE you don't want a new turbo??
- lastly, wrt to a Widefire versus a stock gasket: from my understanding, the Widefire was originally used by Porsche in the Turbo Cup cars to give an extra margin of safety. Given the small cost difference and that you obviously take your car on the track (where God and Dr. Porsche intended!), I think any margin of safety you can get is worthwhile!

As an aside, when you get it apart, check what cylinder the h/g failed on. Most commonly, they fail on #4 because it runs the hottest. One mod I made while the head was off was to install Lindsey Racing's "Steam Vent Kit" which is supposed to eliminate an air pocket in the rear of the head and allow more coolant to pass through the head. I can't speak to how well it works as my car isn't back together yet (again, see my other post!!) but I figured flowing more coolant through the hottest part of the head can't be a bad idea. Again, just looking for that extra margin of safety, you know? Oh, and I installed it myself ... once you get past the fear of drilling a reasonably large hole in the back of your newly machined cylinder head, the install is very straightforward and the pieces seem to be good quality. Plus, the clear hose that comes with the kit will make it super-easy to check coolant circulation, mix, etc.

Good luck!

Ryan

[ryan951s]

Oops, sorry, forgot about the head stud question. From my understanding, the head studs are OK to be re-used, but you should use new washers and nuts for the re-install.

Not that I wish others ill with their cars, but it's almost nice to know someone else is going through right now as well...

R

[kdjones2000]

Hey, I am heading out to the track again this weekend. Maybe we can make it a threepeat!!

On second thought, let's hope not....

Keith

[bleu951]

You can reuse the factory studs, washers and nuts. Take some scotch brite or emory cloth to roughen up the washers on one side, (head side). Take the headers off while still attached to the head. Removing the studs can be a PITA!!! Reinstall the same way, headers on the head.

Send the injectors to Marrin or Witchhunter. Replace the fuel lines. You can use fuel injection hose and special clamps or purchase pre-made hose kits. I just cut the crimps off of the old factory hoses, and used the fitting and heat sleeving along with new hose and FI clamps. It was less than $20. Do NOT USE standard worm/screw drive hose clamps or regular fuel line. This is a potential fire hazard, so use your head
and the correct parts or you will be sorry. Consider the warning. Advance Auto parts has fuel injection hose and special clamps. There are two diameters of fuel hose on the rail. The short 90 degree transfer hose from the damper to the rail was the subject of a recall. It should be inspected carefully and replaced if suspect in any way.

+1 on new coolant hoses, water pump, and belts. The seals have 50k miles on them. If they are dry, flip a coin or roll the dice. Your call. If you are paying someone to do it for you, i would do it while you are in there. If not, what is your time worth? A serious oil leak will ruin your new belts.

My personal opinion is that the wide fire ring is no better than the factory head gasket. But that is just my opinion. I have blown each kind at one time or another, but the factory ones have lasted longer for me. Due to the "more boost" addiction and the open deck design of the engine, head gasket failures are common on modified cars.

You will need new intake manifold gaskets again. You might want to reseal the throttle body while it is off.

[nize]

the widefire gasket has a 'wider' metal ring on one side but not the other. the reason for this is to accommodate an o-ringed block so it won't 'cut through' the gasket material.

question: do you have an o-ringed block?

if the answer is no, the widefire gasket will make absolutely no difference for you, and may actually fail sooner than the non-widefire gasket.

if anyone says anything different, they either don't know or they are trying to sell you something you don't need.

[jmj996]

Originally Posted by nize

question: do you have an o-ringed block?

Nope, stock block. This was the same conclusion on the 'other' 951 forum, don't go with the wide fire. Thanks!

[lleroyb]

When was the clutch master and slave cylinders changed last?

Lou

[jmj996]

Originally Posted by lleroyb

When was the clutch master and slave cylinders changed last?

Lou

I don't have any info on those, but they both work great and I'm up against the wall now for both time and money on this project. I have to get this finished before my next track day on Thursday, 12/4, and I was actually hoping to have been able to drive it around this week before the track day, rather than just throwing it on the track fresh. I finally have it all apart now. Not only did the fire ring fail pretty badly, a LOT of the gasket is rusted through.

[nize]

that looks like some major detonation/knock/ping. what boost levels are you running?

[jmj996]

Originally Posted by nize

that looks like some major detonation/knock/ping. what boost levels are you running?

I don't really know - no true boost gauge. I have a manual under-the-hood boost controller, installed by the previous owner, but I don't know how to set it (anyone heard of InTun?).

The good news is that the job is done and she runs great!!

[nize]

watch out, if you don't know what boost level you're running you will risk blowing the gasket again, or worse.