Removing heads
Removing heads
I am removing the 98HP heads from my '68 Monza project which I intend to replace with the 140HP ones I bought out of California some months ago. The upper row of nuts on the cylinder head tie rods have been bathing in Sea Foam "Deep Creep" for about 10 days now. Must I worry about the order in which I remove them? Is warping the heads an issue when loosening the nuts, or is it only an issue when tightening them? I'd like these heads to be useful to someone when I am done with them.
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- Posts: 1950
- Joined: Wed Oct 13, 2010 12:51 pm
- Location: Northlake, TX
Re: Removing heads
I've never worried about it but I guess I've always removed them in a reverse pattern from installation. People have been removing the lower row 2 at a time to replace o-rings for 50 plus years with no issues.
157 Corvairs, 5 Ultravans and counting
Northlake, TX
Northlake, TX
Re: Removing heads
Thank you. so, how far do the studs themselves have to rotate before I must replace/reset them? 1/8 turn? 1/16 turn? the very slightest amount at all?
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- Posts: 1950
- Joined: Wed Oct 13, 2010 12:51 pm
- Location: Northlake, TX
Re: Removing heads
Try not to let them rotate at all. If they will hold the proper torque and aren't badly rust damaged no need to replace them.
157 Corvairs, 5 Ultravans and counting
Northlake, TX
Northlake, TX
- bbodie52
- Corvair of the Month
- Posts: 11872
- Joined: Mon Aug 06, 2012 12:33 pm
- Location: Lake Chatuge Hayesville, NC
- Contact:
Re: Removing heads
These links may be useful to you...
Removing Corvair Cylinder Heads
viewtopic.php?f=225&t=4063
NEW MECHANICS: Engine Rebuilding & Maintenance Tips
viewtopic.php?f=225&t=4064
Vintage Valve Service and Adjusting video
viewtopic.php?f=225&t=5630&p=38305#p38305
Vintage Corvair Engine Tune up Video
viewtopic.php?f=225&t=5631&p=38306#p38306
HOW TO VIDEOS...
https://www.youtube.com/user/davemotohead1/videos
Removing Corvair Cylinder Heads
viewtopic.php?f=225&t=4063
NEW MECHANICS: Engine Rebuilding & Maintenance Tips
viewtopic.php?f=225&t=4064
Vintage Valve Service and Adjusting video
viewtopic.php?f=225&t=5630&p=38305#p38305
Vintage Corvair Engine Tune up Video
viewtopic.php?f=225&t=5631&p=38306#p38306
HOW TO VIDEOS...
https://www.youtube.com/user/davemotohead1/videos
Brad Bodie
Lake Chatuge, North Carolina
1966 Corvair Corsa Convertible
Lake Chatuge, North Carolina
1966 Corvair Corsa Convertible
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- Posts: 474
- Joined: Thu Jul 28, 2011 6:36 pm
Re: Removing heads
Which method do you plan to use to make up the difference in a early cylinder and a late head?
- bbodie52
- Corvair of the Month
- Posts: 11872
- Joined: Mon Aug 06, 2012 12:33 pm
- Location: Lake Chatuge Hayesville, NC
- Contact:
Re: Removing heads
Installing 4-carburetor 140 hp big valve heads on a 95 hp base engine leaves with the incorrect camshaft, wrong distributor, and a need for 140 hp carburetors and dual exhaust system. The exhaust manifolds and muffler from your 95 hp engine will not fit, as the exhaust ports on the 140 hp heads are larger. The correct bottom end for those heads also uses a harmonic balancer in place of the cast pulley, which was only installed on the low horsepower engine. the 110 hp (2-carburetor) and 140 hp (4-carburetor) engines had the harmonic balancer and the correct 110hp/140hp camshaft, and the 140 hp engine also was fitted with a larger 12 plate oil cooler. A different top sheet metal shroud was fitted to clear the four carburetor mounts and to properly match the larger oil cooler.
What are the final two letters on your engine serial number (see sample below for location)?
This will give you some idea of the differences between the 140 hp engine and the 110 hp engine.
140 hp vs. 110 hp...
140 hp Heads...
- Same high-performance camshaft on both 140 hp and 110 hp engines. Low performance camshaft in the 95 hp engine.
- Same 164 Cubic Inch displacement with same bore and stroke on all 1964-1969 engines.
- Stronger, nitrided crankshaft on the 140 hp and 180 hp turbocharged engines. (Nitriding is a heat treating process that diffuses nitrogen into the surface of a metal to create a case-hardened surface).
- On the 140 hp engine, a 4x1 carburetor arrangement, with two primary and 2 secondary 1-barrel carburetors, connected with a progressive linkage to open the secondary carburetors as you approach full throttle. (Equivalent to a 4 barrel carburetor on the 140 hp engine, vs. a 2 barrel carburetor (2x1) on the 110 hp and 95 hp engine).
- Dual muffler, dual exhaust with larger exhaust ports and larger exhaust manifolds on the 140 hp engine. Single exhaust on the 110 hp and 95 hp engine.
- 9.0:1 Compression Ratio in both 140 hp and 110 hp engines. 8.0:1 CR on the 95 hp engine.
It's all about better breathing at full throttle at the high RPM ranges. At lower RPM the big valves and dual exhaust don't make much difference, and the secondary carburetors are not open for business.
110 hp Heads...
What are the final two letters on your engine serial number (see sample below for location)?
Brad Bodie
Lake Chatuge, North Carolina
1966 Corvair Corsa Convertible
Lake Chatuge, North Carolina
1966 Corvair Corsa Convertible