NEW MECHANICS: Engine Rebuilding & Maintenance Tips

[bbodie52]

A new Corvair owner wrote on the CORSA Facebook Web site that he was just about to start dismantling and rebuilding his first Corvair engine. He asked for tips and general guidelines from other Corvair owners to help him with his project. Here are a couple of things I wrote that I felt might be useful to others on this forum...

ALUMINUM - Dealing With A Significant Difference In Corvair Engines

Most engines manufactured in the 1960s were made from steel and cast iron. Corvairs were different... Most of the engine is constructed from aluminum castings. This material is relatively soft and fragile when compared to the normal materials used in engines, and working on a Corvair engine requires some different techniques. Here are a few tips:

When assembling a Corvair engine, always be careful when you are screwing a bolt into aluminum. It is easy to cross-thread a bolt and damage the soft aluminum threads. Screw the bolt in by hand, and then finish by tightening carefully with a wrench. Use of anti-seize compound on the threads will help in later removal of bolts from aluminum. Use a torque wrench and torque to the proper value listed in the factory service manual whenever possible, to avoid over-tightening the bolt and possibly damaging the soft aluminum threads

By the way, using anti-seize compound on spark plugs to protect the soft aluminum threads in the cylinder heads is probably NOT a good idea. The anti-seize compound may act like an insulating material between the spark plug and the head, causing the spark plug to run hotter than its designed temperature rating. Just carefully screw each spark plug into the head by hand, using the spark plug socket and extension only. Once the spark plug "bottoms out", then add a torque wrench and tighten to the proper torque, using caution not to strip the cylinder head spark plug threads!

This topic is debatable, however. The dissimilar metal contact between steel (spark plug) and aluminum (head) can be a problem. Damage to the head can occur when removing the plug from an aluminum head, and many mechanics swear by the practice of using anti-seize compound with spark plugs in aluminum heads. The recommendation seems to be to use just a trace on the threads.

Permatex 80078 Anti-Seize Lubricant with Brush Top Bottle, 8 oz.

Product Features

- Highly refined blend of aluminum, copper and graphite lubricants
- Salt, corrosion and moisture resistant, this lubricant is ideal for marine use
- Prevents galling, corrosion and seizing and to assure easier disassembly
- Suggested Applications: For easy removal of spark plugs, cylinder head and exhaust head bolts
- Temperature range: -60F to 1600F

However, here is some additional spark plug info from NGK, for your consideration:

NGK Spark Plugs (U.S.A.), Inc. – Aftermarket Division
46929 Magellan Drive - Wixom, Michigan 48393

Tech Bulletin -

Anti-Seize Compounds on Spark Plug Threads

Topic

The use of anti-seize compounds on spark plug threads that have a metal shell plating (i.e. Zinc or Nickel plating).

Issue

Applying anti-seize to the threads of spark plugs that have a metal plating allows the installer to mistakenly over-tighten the spark plug in the cylinder head; This stretches and fatigues the threads of the spark plugs, causing a much higher probability that the plug will break during installation or in some cases upon removal.

Solution

For spark plugs with special metal plating simply do not use anti-seize on initial installation; All NGK Spark Plugs are manufactured with a special trivalent Zinc-chromate shell plating that is designed to prevent both corrosion and seizure to the cylinder head; Thus eliminating the need for any thread compounds or lubricants.

Additional Information

NGK recommends only using spark plugs with metal plating on all aluminum head applications to prevent damage to the head and plug. Metal shell plating acts as a “lubricant” which breaks away from the main body of the spark plug during removal, preventing damage to the spark plug and or threads in the cylinder head.

Summary

All spark plugs that have a blackened or dull appearance on the metal body offer no protection against seizing or bonding to the cylinder head and so it is with these spark plugs that anti-seize would be required. A spark plug that has a shiny silver appearance on the metal body usually indicates that the plug is manufactured with metal shell plating and therefore will not require anti-seize.

ONE MORE THING...

As you dismantle the engine, box, bag and tag all the parts and pieces so you don't lose anything. If you don't already have a factory shop manual, by all means buy a copy! If you plan to reuse the hydraulic lifters, tag them so they go back in the original holes to match up with the original cam lobes. It helps to be organized, which you will appreciate when it comes time to put it all back together!

A bottle of Anti-seize compound is $7.49 on Amazon.com. It lasts a long time. I bought a bottle in 1969 when I rebuilt my first Corvair engine. I still have that bottle and haven't used it up yet!

http://www.amazon.com/Permatex-80078-An ... anti+seize

Permatex 80078 Anti-Seize Lubricant with Brush Top Bottle, 8 oz.

Anti-Seize Compound.jpg (30.8 KiB) Viewed 4318 times

My 44+ year-old can of Anti Seize Compound.

[Mountain Pilot]

Excellent suggestions...

Also on the head bolts and exhaust nuts I have always used anti-seize compound, it allows proper torque settings and easy removal later, The lubricant dries and leaves the aluminum and copper power to prevent the bolts and nuts to rust together.

Also a good torque wrench is a necessary item, do not assemble an engine with-out one.

When rebuilding a Corvair engine I have removed the head Studs and installed Heli-Coils in the block. This assures that the head studs will not pull out of the block later thus requiring a pull down of the engine.

[mart]

Whats Aluminum ? lol......sorry ,I'm British

[Mountain Pilot]

"Whats Aluminum ? lol......sorry ,I'm British"

It is a magic light weight metal used by US turncoats. It's property is that if one lives in the eastern part of our country things made out of it turns into a white power after two winters but out west it stays shiny and new looking forever... I think small amounts have been stolen and taken back to the Old World and is called something like "Al-you-men-eum"

[miniman82]

British translation: al-u-minium. lol

[Lunar_Camel]

Very good info. How long does a typical rebuild take? (If there are no snags along the way).

[bbodie52]

It is hard to predict how long it will take you. There are too many variables. A first-time rebuild always takes longer as you learn and gain experience. Cleaning, sorting and inspecting parts all takes time. Having the heads reconditioned by a Corvair-qualified machine shop takes time. Do you plan on replacing pistons and cylinder barrels with new units or reconditioning and reusing the old ones? Inspection of the old components may determine the direction your overhaul plans take. When I was rebuilding my first engine alone at age 16 I spent all of my summer vacation learning and doing. Some head nuts had to be chiseled and cut out, some studs replaced, carburetors had to be rebuilt, etc.

I would suggest taking your time and enjoy the learning process. Take pictures and post questions on the Corvair Forum as you proceed, to help you figure out what to replace and what can be reused. The process can be enjoyable and the outcome can be a source of pride (the engine I rebuilt in 1969 at age 16 powered the 1962 Monza that I drove at my wedding, honeymoon, and first year of our marriage a few years later).

[Swngaxl]

Whats Aluminum ? lol......sorry ,I'm British

Think fancy alloy beer can!

[terribleted]

Be sure to find someone that knows how to do Corvair engine work to do any machining you have done. I have had cylinders honed to V-8 clearances instead of the tighter Aircooled engine tolerances needed. I have also had head gasket seats milled at an angle by machinists who thought they could do Corvair engines. The over sized piston to cylinder clearances on the one motor caused disassembly and reassembly of the entire engine and purchase of new cylinders, pistons and rings. The angle cut head gasket areas caused finding another set of heads and paying someone else to do them properly. No refunds or help were offered by either or these sloppy machinists. LOL the first one told me that a Corvair engine should be fine with 8-10 thousandths of an inch piston clearance (I beg to differ as the rings all rotate and the piston skirts get scored when they are this loose).