Torque converter disconnect from engine

[Wagon Master]

It's a bit fiddly, but the fan and cover can be removed as an assembly.

[jimbrandberg]

It's a good time now to start soaking the top row of exposed head nuts with penetrating oil. Maybe a little squirt every day between now and next week. It's usually not the end of the world if a stud unscrews from the crankcase along with the nut but much better if you can prevent it.
I like to loosen all 6 head nuts and all 6 rocker studs 1/4 turn at a time in a pattern from the outside in. They might make some scary squeaky noises.

[corvden]

Very much appreciate the tips, have lubricated the head nuts, will keep doing this for days, will have a go at loosing next week.
Due to other commitments, I don't have time for the Corvair exclusively.
These are not another interesting vehicle.

Cheers Dennis

[Frank DuVal]

Dennis, what part of the country are you in/the Corvair from? Different areas mean different head nut removal methods. This is why locations in signatures are so important to get good answers.

Also a picture of the head nuts can help us.

[Dennis66]

Different Dennis here, but in Florida, where stuff corrodes as you watch it (almost), I like to use a small wire wheel on a drill to clean the threads, then run a 3/8-24 nut down on the exposed threads to help clean them. A little heat from a propane torch is also helpful.

[jimbrandberg]

I'm sure Frank will agree that still having exposed threads means you ain't seen nothing yet when it comes to corrosion. <grin>

[Frank DuVal]

You've got threads? That puts you slightly ahead of the game. Now if there isn't even a piece of stud proud of the nut.....

As I said, location of person and where car was for most of it's life is very important to giving service advice. I do not know why people are so scared of telling us, who are trying so hard to help them? Makes NO sense.

[corvden]

Hi Sorry not been on forum for a while, I am not trying to hide anything, live on the Sunshine Coast in Queensland Australia. Climate would be similar to Florida, warm, humid, a mile to the Pacific Ocean, we are heading towards winter, with a minor cold snap currently top 23C min of 17C today.
Car is 67 Monza Coupe, engine is a 110hp but PO installed 140hp heads, Power Glide is standard (no orange marks).

Engine has just been stripped down by generic engine rebuilder, they do many different makes, apparently a few years? ago they did a Corvair engine. Very difficult to find an engine rebuilder. They have sent me a list of issues, some of which I do not understand, here is the basic list:
Cylinders 0.060 oversize, new required + pistons rings
Crankshaft good .010 main & conrod bearings required
Timing gears minor related wear & chips
Head studs, remove reseal, ideally replace
Pushrods Rockers, replace but can be reused
Cylinder Heads very low hardness of 45br, they recommend at least 65br, however all Corvair cylinder heads could be low due to age (I dont know) heads could be reused (a lot of work) there concern the cylinders are likely to sink into the head
Valve springs need new ones
Valve guide exhaust replace inlet ok
Valves some ok, others to be replaced, recommend all replaced
Harmonic balancer replace
Exhaust manifold studs

I think this is about it, apart from various ancillary bits.

Not sure how to approach this, looking at various options, am on a budget but understand $ are involved & most parts are from USA

Aim to drive car every week, performance not required, just keep up with normal traffic flow, which car did on five cylinders & very low on another.

Cheers Dennis

[RexJohnson]

Generally unless the head stud pulls out you leave them alone. Some would never come out no matter what you do. If one unthreads and the threads are still good usally clean threads and put the stud back in with lock tite. It is a good idea using a piece of pipe to torque the studs down to 30# to see if they pull out before assembling the engine. If they hold torque leave them alone.

[joelsplace]

I want to really stress that Rex is correct. Never replace a head stud unless it is damaged. Never remove a head stud unless you are replacing it because it is damaged.
They are probably correct on the head hardness.

[Frank DuVal]

engine is a 110hp but PO installed 140hp heads, Power Glide is standard (no orange marks).

Engine has just been stripped down by generic engine rebuilder, they do many different makes, apparently a few years? ago they did a Corvair engine. Very difficult to find an engine rebuilder. They have sent me a list of issues, some of which I do not understand, here is the basic list:
Cylinders 0.060 oversize, new required + pistons rings Do you mean the existing cylinders are .060" and worn, so new cylinders are required since .060 is as large as one usually goes.?
Crankshaft good .010 main & conrod bearings required
Timing gears minor related wear & chips
Head studs, remove reseal, ideally replace NO! As stated, never remove a head stud unless the threads are bad or it has already unscrewed/pulled out.
Pushrods Rockers, replace but can be reused Normal. There are discussions on the two forums of what to look for with wear that should be fixed.
Cylinder Heads very low hardness of 45br, they recommend at least 65br, however all Corvair cylinder heads could be low due to age (I dont know) heads could be reused (a lot of work) there concern the cylinders are likely to sink into the head

My concern is the valve seats falling out! Head gaskets recessing in to the head might be important of you are planning on 200K miles of use, or racing, but for normal use, ignore. But, valve seats on a 140 are important! Nothing like rebuilding the engine only to have a seat fall out, damage a piston or break into pieces and get in all three combustion chambers! Here we discuss Deep Seats. Several vendors do this work. Maybe they can discuss with your local shop what is needed. Still no guarantee they won't fall out, but it improves the odds!
Valve springs need new ones

Valve guide exhaust replace inlet ok
Valves some ok, others to be replaced, recommend all replaced Good call
Harmonic balancer replaceYes, good call after all these years
Exhaust manifold studs Probably. Usually broken/rusted small by now. I cut them flush, drill with a 5/16" bit a new hole and tap 3/8-16 for a stainless stud.

Code: Select all

@Ken Hand 

have more ideas?

Well that didn't work. Some forums use @ to alert a person to look at a post.

[corvden]

Very much appreciated for your prompt responses
Cheers
Dennis

[jimbrandberg]

I usually have the Machine Shop install bronze valve guide liners rather than guides if the guides are tight in the aluminum heads. My first concern is disrupting the press fit of the guide in the head and my second concern is that GM installed rough guides and then drilled them out locating off the seat so the original hole may not be in the center of the guide. One can get past that by doing the seats by locating off the guide but you need a good Machine Shop who knows what they're doing.
I usually have the Machine Shop flycut the head gasket surfaces.
While the temper of the aluminum is a concern I don't know how you would ever have heads tested before expensive shipping.

Cylinders bored to .060 is the maximum and it does leave the cylinder walls awful thin to be stable dimensionally and it reduces the size of the head gasket surface. I'm not sure I would buy new .060 pistons to match existing cylinders. If buying pistons I would probably got to different cylinders and bore to .030 or something. That's easy for me to say because I've got a lot of cylinders.
Cylinders should be bored in a fixture with plates where the cylinder is torqued down. A Machine Shop would not want to make something like that for just one time. I don't really trust pre-bored cylinders without the pistons in hand so it's a bit of a sticky wicket. Others may say pre-bored cylinders are fine but I have my ways. Another thing easy for me to say because I have local people I trust. One place is expensive and the other place takes forever so nothing ever seems to be easy.

Even if the top crankcase studs are eroded at the top I usually leave them alone. When I CC the heads and figure a compression ratio the heads usually fit a little closer to the crankcase anyway.

I'm not always against a used camshaft and gear if it looks and measures okay. I usually end up with new lifters, usually there's a face or two that look a little off.

With things like rocker arms I'm more in favor of good used than new Chinese so far. Again easy for me to say since I have coffee cans full of stuff like that.

I might consider having an engine shipped on a pallet and in a crate by sea. By air runs into a lot of effort of being certified with no fluids and such. I sent one to Hawaii once and it was cheaper than I thought it would be, although that was like 12 years ago. I don't know who you'd get over here to build and ship an engine however. I had a Business Plan for doing it but never got ahead enough on general repairs and now I'm slowing down my activities.

I'm assembling a few engines from good parts hoping I can sell them when done but it's slow going with waiting for the Machine Shop and all. Everything so far has someone lined up on a "take it or leave it" basis when done.

[66vairguy]

I though in my , for what it is worth. Cylinders that are 0.060" if worn are not worth honing again. Clark's sells new cylinders and pistons, but IT IS UP TO THE BUILDER TO MAKES SURE CLEARANCES ARE GOOD. NEVER install cylinders and pistons unless the gap tolerances are verified FIRST. Same with piston rings - don't use out of the box, verify.

Yes boring a cylinder requires a plate, but NOT honing. With new cylinders and pistons, only a minor honing should be required to get an optimal fit - if that.

There is a steel crank gear and an aluminum cam gear. That crank gear is really difficult to get off and on (big press). The camshaft aftermarket CAST aluminum gears have had a mixed reputation. I now only use billet cam gears from Calif. Corvair. Be warned you just don't warm them up to get a billet gear on the cam. A rig to keep the gear HOT while inserting the cam is required or you will broach the gear and it will come loose! If needed, new cams for the Corvair are getting scarce since the company making the blanks (for decades) has quit!!

Engine shops like to replace head studs or bolts, BUT NEVER DO THAT ON A CORVAIR as others have said. I have a great turbo block with three studs BROKEN OFF FLUSH by some character trying to remove them - now it is a nice paper weight!!! The factory studs are designed to BIND UP in the block!! Only torque head nuts to 30 ft. lbs, no more, no less. NOTE the factory manuals changed this value a number of times so disregard the manual! After many decades of trial and error - 30 ft. lbs. is the accepted number for reliability.

The only time I've seen head gasket SUNK into a Corvair head is when the engine was overheated - which seems to happen more often that though. If that is the case the gasket surfaces will have to be machined to the same plane. WARNING if the gasket surface is down to the spark plug hole threads --- find a new head(s). Yes most heads are soft now, but properly rebuilt they work find as time has proven. BTW when the "FAN/GEN" lamp comes on while driving TURN THE ENGINE OFF IMMEDIATELY as the fan belt is off, or broken and that means NO COOLING. Do NOT try to limp home a few miles without cooling. Yes carry a spare fan belt and tools!

140HP heads tend to drop valve seats. The newer "deep" seats have a good reputation for being reliable IF YOU DON'T OVERHEAT THE ENGINE. Inexperienced shops don't do well with Corvair heads due to the head idiosyncrasies, like valve guide bores that are not exact, factory used a machine to cut the valve guide opening square/concentric to the valve seats. Some shops install new guides and cut the seats concentric - fine if the valve guide bore isn't too far off.

Others can add to this or correct me. Good luck.

[joelsplace]

"Yes boring a cylinder requires a plate, but NOT honing."
That is incorrect. Torque plates are even more important for final clearance.
Let's say the torque plates cause .003" distortion. If you hone to .002" clearance without the plates the distorted areas could end up with .001" interference or .005" clearance depending on which direction they distort (when installed).

Edit added (when installed)

[Wagon Master]

Let's say the torque plates cause .003" distortion. If you hone to .002" clearance without the plates the distorted areas could end up with .001" interference or .005" clearance depending on which direction they distort.

I wonder if the "distortion" you see is really just the cylinder moving as it does when installed and torqued down between the block and cylinder head? I thought that was the purpose of a torque plate. To mimic the hole the piston would live in.