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914World.com _ 914World Garage _ Dropped valve?

Posted by: bongo monkey Aug 10 2003, 02:22 PM

Hello everyone!

A few weeks ago I bought my first ever car, a 1972 1.7L Porsche 914. I decided to take it to a reputable shop to give the car the ol' once-over for problems. After being assured that the car was in drivable condition, I drove my 914 home. A mile from the driveway, I looked into the mirror to find flames trailing from the engine compartment and the engine completely siezed up. Dismay! After pushing the 914 the rest of the way, I try to figure out what went wrong. The PO on my 914 put twin-throat 40 Weber IDF carbs on the engine, and the fire went through the 1/2 cylinder side and destroyed the air filter. Best I can figure it, one of the intake valves dropped and the spark got into the carbs and set the gas on fire. I haven't dropped the engine and cracked open the heads to have a looky-see yet, though. I'm still hanging on to the hope that I'm wrong, and I won't have to replace the piston and cylinder. From what I can see, the engine is still in 1 piece. Am I screwed? So much for that legendary VW reliablity.

Posted by: URY914 Aug 10 2003, 02:30 PM

Welcome and sorry your first post was bad news.

Take a picture if you can. From your discription it is hard to tell what happened. Take the carb and sheet metal off and have a look.

Paul

Posted by: Hawktel Aug 10 2003, 03:06 PM

Bongo thats horrible, man. headbang.gif

Ury is right. Going to need pictures to know whats wrong, not that I'll be much help there.

Have you considered a 6/8 conversion yet?

Posted by: bongo monkey Aug 10 2003, 03:09 PM

I don't have a working camera in the house.

I'll try to take a closer look at the heads and write a better description tonight. There are no gaping holes in the crankcase, at least that's something.

What pisses me off is that it happened maybe 6 minutes after the mechanic told me it should be all right to drive for 6 months. 6 months my ass.

Posted by: bongo monkey Aug 10 2003, 03:13 PM

QUOTE(Hawktel @ Aug 10 2003, 01:06 PM)
Bongo thats horrible, man. headbang.gif

Ury is right. Going to need pictures to know whats wrong, not that I'll be much help there.

Have you considered a 6/8 conversion yet?

I am planning to put a 2.4 or 3.0 six in the 914. It would take me at least a year, probably 2 to save up to get all the parts though. I would like to drive the car for longer than a hour during that interval, though. I thoroughly enjoyed my brief time in the car before it went into a coma (it's not dead, it's not dead)

Posted by: bongo monkey Aug 10 2003, 07:50 PM

I took a closer look at the heads, and there are no holes anywhere. At least 1 intake valve is still working from what I could see through the intakes. I couldn't see well enough to see if both valves were there. The head bolts were nicely rusted shut, so I couldn't crack them open. I will find out for myself when I drop the engine and open the heads. But I came on this board with my problem to get a second opinion. Is there any reason other than a dropped valve why a seemingly well-running engine would suddenly sieze up and catch fire? I'm not too familiar with 914's, and I havent done a proper diagnosis.

Thanks, everyone, and sorry for the lack of pictures owing to my lack of camera

Posted by: URY914 Aug 10 2003, 08:20 PM

Pull the valve cover off and take the rocker arms off. See what the springs and valve stems look like.

This should tell you alot.

Paul

Posted by: need4speed Aug 11 2003, 11:51 AM

. . . and NEVER trust your baby to a mechanic again.

Nobody will ever really care about your car more than you. To a professional, it's just a way to earn a living. To you - it's your baby.

wub.gif


I'd say you're more than lucky that the fire stopped where it did. Once that aluminum crank-case and transaxle catches on fire, there's just about no stopping it. Maybe now's a good time to think about investing in a fire extinguisher?

Can't wait to hear what really went wrong.

Posted by: bongo monkey Aug 20 2003, 04:11 PM

Ripped open the engine. It turned out not to be a dropped valve, but the valve seat had bent and jammed the valve where it impacted the piston. So now I just have to replace a single piston and rebuild the left cylinder head and hopefully it will be running.

Posted by: ArtechnikA Aug 20 2003, 04:56 PM

QUOTE(bongo monkey @ Aug 10 2003, 12:22 PM)
The PO on my 914 put twin-throat 40 Weber IDF carbs on the engine... So much for that legendary VW reliablity.

can't really blame VW for PO modifications ...

sorry for your loss. a dropped seat can happen at any time - doesn't seem to matter much what immediately preceded it. continued overheating seems to make the issue worse (which is a little odd, since carbs tend to make these motors run richer...) there are a few places that are the 'go-to' places for head repairs - i'm sure someone will chime in with the current list ...

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