Field Expedient Engineering: JB Weld Porsche Cylinder Head Repair

Murilee Martin
by Murilee Martin

When your 1980 Porsche 924 craps out minutes after the start of its first race and you’re in rural Texas, parts might be a little hard to find. You won’t get far with a blown head gasket and big ol’ notches burned in the head itself. But, damn, the clock keeps ticking! The Moose Knuckles team called every junkyard within 500 miles, but nobody had any 924 (or Audi 100) cylinder heads. In fact, nobody had ever heard of them furrin thangs.

The Moose Knuckles were able to find a head gasket a few hours’ drive away, but they came up with exactly bupkis on the head. But then one of the guys remembered the fine print on the JB Weld package: Repairs Engine Blocks. Block, head, what’s the difference?

Picking up some JB Weld and JB Kwik, the Moose Knucks got right to work. Sure, combustion-chamber temperatures get higher than the JB Weld-rated 500 degrees F, but we’ve seen such repairs work in the past… on cast-iron heads. What will happen with an aluminum head?

Fill in the holes with that magical gray stuff, sand it down, and slap the head back on the engine. Take the car on the track. Return behind the tow truck. Repeat. Endlessly.

Because the track exit at MSR comes before the transponder loop, and the Moose Knuckles’ Porsche never managed a full lap under its own power, all those laps that ended on the hook didn’t count. Official race results counted the car as a DNS. On the bright side, the Moose Knuckles took home the I Got Screwed award.

Just so you don’t think JB Weld repairs always fail at LeMons races, here’s a JB-patched E30 oil pan from the same race. The car wiped out, bottoming the pan and cracking the hell out of it. Thanks to a generous application of metal-filled epoxy, the car finished the race.





Murilee Martin
Murilee Martin

Murilee Martin is the pen name of Phil Greden, a writer who has lived in Minnesota, California, Georgia and (now) Colorado. He has toiled at copywriting, technical writing, junkmail writing, fiction writing and now automotive writing. He has owned many terrible vehicles and some good ones. He spends a great deal of time in self-service junkyards. These days, he writes for publications including Autoweek, Autoblog, Hagerty, The Truth About Cars and Capital One.

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  • Panzerfaust Panzerfaust on Apr 29, 2011

    I've seen J-B weld used to repair VW vanagon crank case. Heat really wasn't an issue-except when the owner would use his Coleman catalytic heater to warm the engine up in the winter so it would start.

  • John Horner John Horner on Apr 30, 2011

    JB Weld to patch up an oil pan? Sure. JB Weld to fix a head .... never had a chance. JB Weld can't take the mechanical stresses or temperature. Didn't anyone at the track have a TIG welding set up? That could have worked.

    • Panzerfaust Panzerfaust on May 01, 2011

      Probably because a good portable TIG welder costs 3 times as much as any of the cars do. As I posted above, welding an aluminum head in the field is an iffy proposition. First it has to be of an alloy that can be welded, second the contamination from years of fuel, oil, coolant and other grime creates such porosity that you can't get much of a bead at all, or you have a weld fails almost immediately. But it would certainly be worth a try if the head was scrap anyway.

  • The Oracle This thing got porky quick.
  • Kwi65728132 I'll grant that it's nicely kept but I'm not a fan of the bangle butt designs, and I know better than to buy a used BMW while living anywhere in the world other than in the fatherland where these are as common as any Honda or Toyota is anywhere else.
  • ChristianWimmer When these came out I thought they were hideous: now they’ve grown on me. This one looks pretty nice. Well-maintained, low mileage and some good-looking wheels that aren’t super fancy but not cheap-looking or boring either, they are just right.
  • Aja8888 Someday in the far away future, all cars will look the same, people will be the same color, dogs will be all mixed beyond recognition, and governments will own everything. That car looks like my son's Hyundai Tucson without badges.
  • Tassos Of course, what the hell did you expect? A SERIOUS, BEAUTIFUL car you can ACTUALLY USE AS YOUR DAILY DRIVER???............. NOOOOO, THIS IS TIM WE ARE TALKING ABOUT. SO HE FINDS SOME OBSOLETE POS WHICH IS 22 years old, .............AND HE PURPOSELY MISSES THE BEAUTIFUL MODEL, THE Classical Beauty E39 that ended in 2003. ...........So he uses his column as a WASTEBASKET once again, to throw the first year of BMWs BANGLED 5 series (as in the INFAMOUS CHRIS BANGLE WHO SCREWED UP THE DESIGN ROYALLY). ................................................ As Dr. Evil, Fake Doctor Jill Biden would scream at the top of her voice, so her senile idiot husband could hear her, "Good Job, (Tim)! You answered all the questions and ticked all the boxes!" ..... KEEP UP THE S---Y work, Tim!
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