eworkley

Looks like I've blown the head gasket on the "s". Anyone got an idea of what it will cost to replace...or has anyone done it themselves?

eworkley
87944S

aka 951

make sure that's the extent of the damage first. If you blew a headgasket on an NA something is probably very wrong unless you overheated it. How did it blow?

eworkley

Not sure...was having some wierd starting problems that no one could figure out so I took it to a longtime porsche guru. When he pressurized the # 4 cylinder it blew out coolant from the res. According to him it's most likely a block od head gasket. Do not know what would have caused it, no overheating...

eworkley
87944S

951and944S

Head gaskets go all the time on all types of cars, a moderate tally of miles is reason enough for a blown head gasket, possible previous repairs made were not performed to specifications.
I've performed this job several times, two words of caution for the DIY'er on this one.

Find a reputable machine shop, if cylinder head needs resurfacing, as this engine already has 10.9:1 static compression ratio, removing more than .010 is not recommended, there is no perfromance gain to be had by removing more, trying to increase performance, as detonation will only occur, until DME copensates for this by retarding timing...(with lack of 93+ octane fuel)

The correct factory procedure for timing (dialing in) the camshafts, requires the use of two dial indicators, mounted to the top of the head. The camshaft gear is slotted, allowing precise adjustment.. There is not much room for error here as the range of spec is very small.
If you don't feel comfortable, with undersanding, these methods, you could possibly damage a camshaft, or both, making the job, much more costly than the simple gadket replacement..

Terry

aka 951

I've owned about 25-30 cars. Haven't blown an NA headgasket yet (apart from overheating). I'd make double sure there wasn't a more serious problem with the motor such as a perforated head. It just doesn't happen on normal, well engineered cars unless something is really wrong (apart from turbos). Sad but true. Maybe you're lucky but I doubt it. Have a professional take a look at the head and block after you pull the head off. On the S you can remove the head without removing the cams if you are careful not to scrape the aluminum up in the camshaft portion of the head (it is one piece as opposed to the 2-piece design of the NAs).

951and944S

AKA, then you'd have to agree that when talking about cars, "never say never"..
In all things, not just cars, there's an exception to every rule...
Eworkley states that he never had overheating problems, and experienced a "starting problem that was weird"..!
Higher compression on S car engines is, as you know, due to less volume in the combustion chamber, which if coolant entered a cylinder, could cause an already somewhat deteriorated head gasket to "blow" across to the water passage, yes..?
Water or coolant cannot be compressed, and can wreak havock on pistons and rods, when attempts to do so, cause more serious damage, why could it not finish off an old head gasket..?

IMO, this would also expalin his "weird" starting problem...Small amounts of coolant in one cylinder caused the engine rotation to slow when TDC of that cylinder was reached..

Premature head gasket failure, without "overheating" can be caused by corrosion and electrolosis caused by the reaction of the metal studs and the alluminium block and heads, and the use of coolant manufactured with the use of chlorinated water. Manufacturers of alloy engines, for years have documented this and recommend coolants without chlorine, and therefore also recommend the use of "distilled" water for reducing the coolant to water ratio..

Peace

Terry

eworkley

Terry
Your reply, simple, yet, has been undoubtably one of the most educational posts that I have recieved in nunerous, previous attempts in solving a most difficult starting problem. Not to discredit any replys but no one suggested the head gasket. A reputable tech discovered the problem. I did not however realize the importance of diluting coolant (even after performing most service/repairs myself) and the possible damage it may prevoke. My hat is off to you and may this be an advisement to all of us whom did not know.

eworkley
87944S

aka 951

Some motors are more succeptible to the problem than others. The 944s (apart from the turbos) are not known to be as far as I know. I've never had a problem and I use tap water with almost no coolant in my 924S (for the last 35k as I am lazy...lol...the car also has 223k on it to boot!). Even so, Porsche reccomends only using phosphate free coolant. There is a similar post on Pelican to this effect.

There is at least one European car company that has had a problem with the blocks actually pitting on the headgasket surface. Also, some types of heads have been known to become porous over the years. Have the head pressure tested to check for porousity and also tested for straightness. Best of luck.

eworkley

aka951...
if only I lived in sunny cal...Umm...lets see...Its 15 deg outside...need that higher % of antifreeze...thanks for the reply

looking for warmer weather
eworkley
87944S