Blown Head Gasket, can it be changed in the car? Options

[Mr.C]

I wonder if your head is torched in the spot where the ring failed. Had this happen to my 2.0 I ignored it for a while thinking it was an exhaust leak. I did the lap thing when I reassembled it after being advised by my friend who repairs VWs for a living.
In fact I just helped a friend out that had this exact thing happen to his 1.7 Head was torched and the cylinder was cracked. Replaced the head and cylinder, lapped both sides and all was good.
We are cheap bastards and didn't want the machine shop invloved. (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[Mark Henry]

You do 'em your way, I'll do'em mine. I haven't used them in 15yrs...couple hundred engines I'd guess.

I use shims under the barrels...and I know the CR of every engine I build.

Ask what Jake uses.

BTW I see this quite often (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif) and didn't have to look very hard for a set like these.

[type11969]

The 2.0 and the 1.7 I just pulled apart had "sealing" rings that looked like the above picture . . . enough to convince me not to use them again.

[Cap'n Krusty]

QUOTE (eric914 @ Jun 27 2005, 12:49 PM)

The tech bullitan does not say the heads have been redesigned. It says the following modifications have been to the remanufactured engines. As for longer rods and cylinders, why? The bulitan clearly states use a larger aluminum shim on the block side to compensate for the removed gaskets. As for not lapping cylinders and all that expensive machine work, do you lap valves after all that expensive head work? Of course you do (or the head remanufacture did it for you). As for this being only for type II's the following is from the PET. 039 100 031 X SHORT ENGINEEXCHANGE74 KW, 100 DIN-PSWITHCYLINDER HEADOIL COOLERFLYWHEEL 1 039.GB

The rods aren't longer, they're different. Look at the bulletin. The new haeds come with a tech note right in the box that addresses the redesign question.
As for lapping the valves, you're spinning a SINGLE valve in it's seat, which has been centered on the guide. When you lap the cylinders, you're holding each cylinder, one at a time, in your not-so-calibrated hands and spinning them in the precisely (and expensively) planed spigot in the head. And you're gonna hold that plane? Maybe not.
As to the replacement engines, I've never heard of ANYONE ever buying a reman 2 litre 914 engine from Porsche. I do concede it's probably happened, though. Note that the suffixes "B, C, and D X are on the list, the "plain" isn't. The suffix is the final delineator of the part number, and is conspicuous by it's absense. If it is in fact an engine rebuilt after the date of the tech bulletin, and is covered on the list, then it has the revised rods and pistons. Unless you have those, the changes don't apply to your engine. The Cap'n

[McMark]

It would be stupid to lap cylinders to heads IF your head sealing surface has been trued and your cylinders have been trued. BUT if you doing a cheapie rebuild (nothing trued) lapping is a viable option. My only thought on lapping is that since the head is aluminum it's the piece that's going to receive the most cutting. So you're heads will take a cut and the cylinders will stay "wrong". If you make some effort to true your cylinder (sandpaper on glass) and then lap to the head you can improve your sealing surface. But that's still not a good alternative to professional truing. It's for a DIYer who's just looking to get a few more miles out of a worn engine.

[type47]

JAKE! what say you? this is interesting.....

[Jake Raby]

This topic is gone over extensively in the first of volume of my new handbook series- Sealing The Type IV Engine.

I don't use gaskets and do go over the entire process to create a leak free engine, both from oil leaks as well as combustion leaks.

The handbook should be printed in 6 weeks.

Sorry for my lack of presence guys, the copycatter really has me watching what I post and not saying much that he can cut and paster- thats why its all going into print now instead of the net....

[Dead Air]

head with rings!

[Mueller]

QUOTE (Dave Eddy @ Jun 27 2005, 09:46 PM)

head with rings!

and your point is????? (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)


how many miles?
is it 100% original??
if motor was rebuilt, was it done correctly?

too many unknowns to blame the ugliness on the use of gaskets/rings.........

[Dead Air]

QUOTE (Mueller @ Jun 27 2005, 10:12 PM)

QUOTE (Dave Eddy @ Jun 27 2005, 09:46 PM) head with rings! and your point is????? (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) how many miles? is it 100% original?? if motor was rebuilt, was it done correctly? too many unknowns ...

[QUOTE]

What's my POINT? (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/beer3.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/beer3.gif)

I ran this car in the 1996 24 hours of Le Mans, It dyno tested at 170 HP plus!

The only reason I didn't finish the race was because I had to pee and I ran out of gas.

Otherwise, the engine was good, I just tore it down to add something to the conversation. Ran like a top, like new! Didn't leak or burn any oil. Comp test said I was actually at 11:1 compression! 102 lbs psi

Heads look good, valves look good, plugs look good.

The question is what do I do now?

Lap the heads or replace the "gaskets"?

I guess that's my point.
OK?

[Mr.C]

QUOTE (Dave Eddy @ Jun 28 2005, 09:06 PM)

The question is what do I do now? Lap the heads or replace the "gaskets"?

Lap (IMG:http://www.914world.com/bbs2/html/emoticons/monkeydance.gif)