140 engine rebuild

[SpiderMan]

How many valve spring compressors do I need to buy before I get one that works?
Neither of these work.
The C shape device has two problems. The upper part of the C leg hits the head on every valve accept the two ends. It's too flimsy and runs out of thread before compressing a spring enough.
The tubular unit - I don't have the strength to compress nor how many times I hit it with a hammer per instructions do the keepers come off.
Got any recommendations?


Edit - I was using the tubular one wrong - figured it out. I am managing now. Got some worn valve guides - damn!

I admit I've lost track of which head is passenger side 1/3/5 and which is drivers side 2/4/6. I had incorrectly assumed they were unique and mirror imaged. Nope they are the same.
Does it matter then which side they go back on?
If so, is there some visually distinguishing difference between the two?

[bbodie52]

...I admit I've lost track of which head is passenger side 1/3/5 and which is drivers side 2/4/6. I had incorrectly assumed they were unique and mirror imaged. Nope they are the same.
Does it matter then which side they go back on?
If so, is there some visually distinguishing difference between the two?

The 140hp heads are essentially the same. What matters is which way the vacuum balance connection tubes from the primary carburetor mounting pads are pointing. If you swap the heads, the vacuum balance tubes will be pointing to the wrong end of the car. (This is true with all non-turbo Corvair heads. Even turbocharged heads are different, as the right head is the one with the oil return tube hole for the turbocharger). You need the vacuum tubes to be pointing forward, for proper hookup to the vacuum balance tube that crosses between the heads. Also, the cylinder head temperature warning switch is supposed to be on the right head, (where the connecting wire routes from the oil pressure switch (next to the alternator), and then routes to the bottom of the right head, and then back out to the car wiring harness connection near the ignition coil. On the Corsa, the cylinder head temperature gauge thermistor was mounted on the left head.

Vacuum Balance Tube - Head Orientation.jpg (63.49 KiB) Viewed 1269 times

You can see where the vacuum balance tubes connections stick out from the carburetor mounting pads. If you mount the heads on the incorrect side of the engine they will be pointing the wrong way and cannot be reconnected to the vacuum balance tube!

[Dennis66]

To simplify: each side has to have the balance tube stub facing forward. I ended up with a piece of 2 x 8, 6 screws (screwed in pairs to a depth where they held the valves in a closed position), a length of angle iron and two maybe 9-10" threaded rods, one at each end to secure the angle iron. The head drops on over the rods (through a top head bolt hole on each end), the angle iron goes over this with nuts providing a prying surface, and I made a "spoon like" lever to compress the springs. It looks kind of "red-neck engineered", but I'm a product of multiple generations of the south and it works fine for me.
A machine shop can knurl the valve guides and doesn't need to be Corvair specialized to do this (replacing guides gets a bit more tricky because the guides are positioned to the seats and not necessarily centered to the guide holes in the head). Dennis

[erco]

Re: Valve spring compressor

I use one of these lever-type ones, but it requires drilling a hole in the workbench to run a threaded rod up through the top surface to act as a rocker stud. Works great. https://www.summitracing.com/parts/wmr-w84002

[SpiderMan]

Ok, got it on the correct positioning of the headers. Thanks.

Almost every exhaust valve guide is ovalized and doesn't seal well. All but one intake is fine.
There may be one or two guides that are bad enough to be beyond knurling as a fix.
Replacing must be a precise operation to maintain the necessary concentricity to the seat.
Is there a drill guide kit that works with the corvair head?

There were not valve seals on any intakes.
Is this normal?

[Dennis66]

While I have seen Corvair valve stem seals, I've had 3 set of heads apart and yet to see one with any stem seals. This is my understanding: Because the Corvair cylinders and valves are basically horizontal, the stem seals are not as necessary as where the valves are more vertical (V-8 or old straight 6). Now there could be a problem on the intakes because of intake manifold vacuum that could suck oil in through the stems. I believe "66" mentioned this in another post.
As to replacement guides: this could be a problem. I don't know of a specific drilling alignment tool, but I suspect the "Corvair head specialty" places have one, or have made one. I pointed out that the Neway cutter will cut the seats to be concentric with the guide, but the guide needs to be close. Dennis

[66vairguy]

While I have seen Corvair valve stem seals, I've had 3 set of heads apart and yet to see one with any stem seals. This is my understanding: Because the Corvair cylinders and valves are basically horizontal, the stem seals are not as necessary as where the valves are more vertical (V-8 or old straight 6). Now there could be a problem on the intakes because of intake manifold vacuum that could suck oil in through the stems. I believe "66" mentioned this in another post.
As to replacement guides: this could be a problem. I don't know of a specific drilling alignment tool, but I suspect the "Corvair head specialty" places have one, or have made one. I pointed out that the Neway cutter will cut the seats to be concentric with the guide, but the guide needs to be close. Dennis

The Chassis Shop Manual states: "On intake valves, install new valve stem oil seal using special plastic protector sleeve to prevent damage as seal passes over valves lock grooves".

All the Corvair books I've read over the years say to intsall INTAKE valve seals, but DO NOT install seals on EXHAUST valve stems.

All the heads I've had rebuilt they all had new intake valve stem seals, none on exhaust. Why none on the exhaust? Unlike an inline six of V8 on Corvair heads oil drains away from the valve stems so exhaust valve stem seals are not needed in in fact they would increase wear due to less lubrication. On the intake valves you have a vacuum and to prevent excess oil being pulled into the intake tract valve stem seals are used - at least that was GM's reasoning. Almost two million Corvair engines were built and they all seemed to have a reasonable life span vs. other engines of the era if properly maintained.

[erco]

Don't knurl valve guides, that won't last. Have bronze liners/sleeves put in instead of replacing the entire guide. My shop charged $25 each.

Yes to intake stem seals only. I rarely see intake guide wear, only on exhaust valve guides. Intake valves run much cooler than exhaust, since they get cooled by the incoming mixture when they open. Exhaust valves heat up when they open since much of their heat transfer goes through the valve seat.

[SpiderMan]

Erco, check your private mail.

[Dennis66]

All the Corvair books I've read over the years say to intsall INTAKE valve seals, but DO NOT install seals on EXHAUST valve stems.

Not to argue but I was looking at my '61 shop manual yesterday as I was referring for other work. It was right here on the cylinder head section. The assembly procedure, including pictures had no mention or pictures of valve stem seals. Now I do remember some heads way back having them. I don't recall if I put them on the Greenbrier I rebuilt 10 or so years ago (but I probably did). I know the bronze guides in my 102 heads are not the same size as the stock guides. Dennis

[66vairguy]

All the Corvair books I've read over the years say to intsall INTAKE valve seals, but DO NOT install seals on EXHAUST valve stems.

Not to argue but I was looking at my '61 shop manual yesterday as I was referring for other work. It was right here on the cylinder head section. The assembly procedure, including pictures had no mention or pictures of valve stem seals. Now I do remember some heads way back having them. I don't recall if I put them on the Greenbrier I rebuilt 10 or so years ago (but I probably did). I know the bronze guides in my 102 heads are not the same size as the stock guides. Dennis

It's possible. A lot of changes were made from 60 to 62. The shop manuals are sometimes in error or lacking. NOT bashing the manual writers, but engineering changes/corrections didn't always make it to the manuals. Keep in mind back before computers, manuals had to be created and printed many weeks before the new cars were actually built! I'll post a list that some folks put together with SOME of the known errors and corrections.

[SpiderMan]

Head work -
Almost all exhaust valves are loose in their guides and one intake is loose.
After checking with local machine shops I've found they are either too busy, destroyed by flood waters, or no bid when you mention Corvair. I could expand my reach out of my home state, or, I could do the valve guide replacement/liner myself.
Doing it myself:
The big challenge is to maintain concentricity with the valve seats which I do not plan to replace. You'd think that the existing guide hole would centralize the drill but this may not be the case with an ovalized hole. I've drifted off center even with a pilot hole before. There are some tools available that aid in keeping the drill concentric to the seat. Typically they include a drill guide with chamfers to match your valve seat, a shaft the same diameter as a valve stem to set up this drill guide, and some means to hold the drill guide in place after setup. Goodson has a marvelous tool to accomplish this, Unfortunately, the tool is ~$800.00 which is hard to justify for one set of heads. The rare/discontinued Lyle 590000 tool is another option. There's one on Ebay at $400.00 and heading up in a bid war.
I think I can buy the drill guide and rod separately, relatively inexpensive. Then I would just need a large C-clamp with somewhat deep reach that has am access hole in the foot of the end opposite the threaded rod end. I would clamp the dill guide in place using the rod to ensure its' angle is correct then withdraw the rod and drill down through the C-clamp access hole.
Can anyone think of such a C clamp?
Or, I could mail my heads ($) somewhere in the country and have an expert replace the guides. ($)

[66vairguy]

While overheating the heads is a cause of loose valve seats, worn out guides is another not often mentioned. Worn guides cause the valves to randomly seat a little off center a causing the valve to seat contact to be uneven. The "wobble" when the valve closes can eventually causes the seat to come loose.

My point is I would have the guides AND seat replaced. This is one of the major obstacles to owning a Corvair because rebuilding two heads can run anywhere from $800 and up, depending on their condition. New valves and springs are strongly recommended. If the engine has a lot of miles on it, then it should be rebuilt. This is when many throw in the towel.

Recently someone mentioned there are probably only 4 or 5 good Corvair head shops now.

I can only suggest one shop that has been doing Corvair heads in S. Calif. for decades and he has done them for vendors and Corvair repair shops.
That would be "Bruce" at Engine Machine Serive in Inglewood, Ca. 310-641-7019. I used him many years ago, but he did a set of heads for a local club member in 2020.

Maybe others can help with shops they KNOW rebuild Corvair heads. A shop that does VW or Porsche heads is NOT the same as a shop that knows Corvair heads. It's like saying a Ford V8 and Chevy V8 are the same.

[erco]

Bummer that there are no local resources for you. Before spending $800 to rebuild yours, consider buying rebuilt heads for $1000: https://www.ebay.com/itm/115479021118

Or these with deep seats (not sure if its only 7) for $1500: https://www.ebay.com/itm/125433005928

I met the seller, Starr Cooke, very cool guy and he knows what he's doing.

[66vairguy]

Bummer that there are no local resources for you. Before spending $800 to rebuild yours, consider buying rebuilt heads for $1000: https://www.ebay.com/itm/115479021118

Or these with deep seats (not sure if its only 7) for $1500: https://www.ebay.com/itm/125433005928

I met the seller, Starr Cooke, very cool guy and he knows what he's doing.

I've never dealt with Starr Cooke, but over the years I've run into folks that say he is the greatest and others who only have negative things to say about him and his work. I'm not sure why this contradiction exits, but I'd deal with a reputable shop/vendor.

I checked the ebay site and Starr also had a "FULLY REBUILT" set of 140 HP heads for $995.00, BUT the add says "staked seats". Stacked seats are NOT fully rebuilt heads in the world I live in!!! That ad alone would make me weary. After years of forum comments many have reported that "stacked" seats do come loose.

In 2020 the fellow who had 140 heads done by Bruce at Engine Machine said the invoice was $1,300.00 for new valves, springs, guides, seats, and machining the gasket and quench step. The WAS three years ago.

[erco]

Well I was impressed with Starr and his home shop. I bought a pair of his rebuilt 140 heads for spares, so I drove 2 hours to his house near San Diego to get them and we yacked for at least 2 hours, a very knowledgeable fellow. He and his wife are Corvair lovers and buggy racers. He keeps a detailed log of every head he works on and what he did to repair it. He strikes me as a good and conscientious machinist who would stand by his work.

The first thing on Google is positive, and if you can't trust Google... :)

https://corvaircenter.com/forum/viewtopic.php?t=770273