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The big bang and rocker cover woes
Posted by: flamingchariots ()
Date: November 04, 2017 05:44PM

Back about ten years ago, my '67 Monza 110 PG suddenly developed a nasty banging sound when started. Wasn't run long--- a minute maybe. After the next time starting, it got louder. I never tried to start it again.

Present day: I finally decided to look into it. The easiest thing for me was to remove the rocker covers and see if something obvious was broken. I can't see anything amiss, but I am posting some pics for those with better eyes.

Of course, Murphy's law prevailed. One of the bolts for the cover broke off. Tried grabbing the nub with vise-grips, but was unsuccessful. Am currently soaking with Kroil. What is the best way to get it out? I don't weld and don't have acetylene torches.

So that's the 1st question.
The 2nd is: would using a USB endoscope down the spark plug holes accomplish anything? I have yet to pull a head off or drop a drive-train.
Looking at the bolts above the rocker cover, I expect nothing but more problems.

Passenger side pics:

Kevin
Medina, OH

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Re: The big bang and rocker cover woes
Posted by: flamingchariots ()
Date: November 04, 2017 05:45PM

Driver's side pics:

Kevin
Medina, OH

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Re: The big bang and rocker cover woes
Posted by: moomba32 ()
Date: November 04, 2017 06:50PM

I've had results using a propane torch, with aluminum it's easy to get too hot with a ox/act torch, aluminum melts easily. The theory as I understand it is that aluminum heats faster than steel, better conductor, and because it heats faster grows before the steel gets hot so if you're quick it gives you that moment to turn the bolt with the lowered friction of the now expanded aluminum.
People use bees wax with heat seems to work it's way in.
If you can get it to turn even the tiniest amount don't push it, move it back and forth over and over, usually each time it will turn a little further eventually coming loose.
Good luck.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: The big bang and rocker cover woes
Posted by: Frank DuVal ()
Date: November 04, 2017 10:04PM

Harbor Freight left handed drill bits.thumbs up

Frank DuVal

Fredericksburg, VA

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Re: The big bang and rocker cover woes
Date: November 05, 2017 01:24AM

Use an electric heat gun and candle wax. I had a broken bolt on the flange that mounts the fan. Using heat + wax, I was starting to drill it with a left hand bit and the broken piece just unscrewed itself before the bit could get a bite!!
While you are there with the heat gun, put the rocker cover back on, use a wire brush to clean all the rust out of the exposed rusty threads on the upper head bolts, the heat each one and melt candle wax into the threads of each.

Take out all the spark plugs and listen at each cylinder using a section of hose to hear which one is making the racket when you crank the engine over with the starter. Use a remote starter button connected to the battery + and the purple wire that goes to the starter.
After you know which cylinder is noisy, you can then look at the rocker arm area to see if the noisy cylinder has a valve not moving closed properly (dropped seat will often be cocked sidewise and that cylinders valve won't be returning to closed position) Compare to a neighboring cylinder to see a difference.


Dan Davis ~ Pierce County, WA ~ CORSA Western Director + Corvairs NW + North Cascades Corvairs + Corvanatics
1966 Corsa Turbo coupe ~ ~ 1966 140 Corsa ~ ~ 1965 Monza 140/4 'Vert Sierra Tan/Fawn ~ 1964 Monza 'Vert (SOLD) ~ 1960 Monza Ermine White/Red PG ++ ~ 1965 Monza 140/4 Evening Orchid w/ ivory/black interior ~ 1962 Monza Wagon 102/4 ~ 1963 Rampside/Scamper ~ 1963 Red/Greenbrier ~ 1969 Ultra Van #468

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Re: The big bang and rocker cover woes
Posted by: JimBrandberg ()
Date: November 05, 2017 05:37AM

Dan's advice is good. I would also do a Compression Test followed by a Leakdown Test if compression is poor.
Jim Brandberg
Isanti, MN
CorvairRepair.com

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Re: The big bang and rocker cover woes
Posted by: BobV66Vair ()
Date: November 05, 2017 09:21AM

I have a little torch head from Home Depot and a small bottle of MAP gas. It is amazing how much the heat can loosen things. MAP will melt the aluminum so be careful.

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: The big bang and rocker cover woes
Posted by: flamingchariots ()
Date: November 05, 2017 05:25PM

Thanks to all for the good advice. I'll be trying my luck later this week.
We've been riding out tornado and large hail warnings late this afternoon.
Storm is still not over.

Kevin
Medina, OH

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Re: The big bang and rocker cover woes
Posted by: corventure Dave ()
Date: November 06, 2017 11:44AM

I have also had good luck with a Dremel cut off wheel. Apply heat as indicated, but also cutting a slot in the broken stud with the Dremel and extract with a flat screwdriver.

Corventure Dave

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