All Small Six Winter Project: Better breathing with a large log

[awasson]

I just acquired my winter project. I picked up a C9DE-6090M large log head. It’s not the desired mid/late 70’s head but it’s much bigger than the small log head that came on my 66 Mustang Engine.

I did some preliminary review but I have to completely strip it, have it magnafluxed and cleaned up. I’ll give it a valve job and make sure it has hardened seats and replace the guides. I’m going to do as much porting as I can and clean up the castings to make it flow as best as possible. I’ll mill it for a direct 2V plate for my 38/38 too.

So far it looks like it has 1.75” intakes and 1.38” exhausts. The log intake is 1.75” too. I just measured with a vernier caliper. I’ll CC the chambers and see what I get. I think it should have 62cc chambers so I’ll need to mill it appropriately to get the compression up.

I’ll also need to look at what I can get for rockers. I’d really like to go with 1:6 ratio rockers to take full advantage of the camshaft I’m running but in any case, I will need adjustable rockers and pushrods.

Aside from some rust in the log and a bunch of dust and debris on the head, it’s in pretty good shape. The chambers are oily and greasy, the rocker assembly was removed so the valves were all closed and none of the exhaust bolt holes are cracked or broken.

Fun times!!

 

[DON]

Nice project . It will be interesting to follow

 

[awasson]

I wonder if anyone can suggest what to do about the exhaust valves... It has 1.75” intakes and 1.38” exhausts but I have read that you can increase the exhausts to 1.5". If I'm going to go to the trouble of skimming the head, porting (cleaning up) the intakes and exhausts, adding that port divider between 3 & 4 and updating the rockers and so on, I might also want to increase the exhaust valves to get the most out of it.

@DON this will be getting those springs you sent me. I think they must be 289 or 302 springs from the specs you provided. I've compared them to what's on this head and they are substantially stiffer and beefier.

 

[bmbm40]

The Falcon Performance Handbook states that they are successfully using the 1.468" intake valve from a 144 c.i. as an exhaust valve a simple modification because stem is correct length and diameter only seat needs to be cut larger. Stock exhaust valve is 1.38".
Could be an option.
The Handbook also states that back cutting the intake valve also has the same effect as high-lift rocker arms or cam for a fraction of the price.
Also mentions that the 1.50" exhaust valve is a good option.
Just FYI.

 

[DON]

I would like to see a photo of a back cut valve and an uncut one side by side.

 

[powerband]

for your edification:
.
Check out Differences in Combustion Chambers from your C9DE vs DODE 'large log' heads. "Closed Chamber' DODE head has the large runner, larger Carb port like C9DE but DODE-A combustion chamber is optimized for Flat Top piston /Shorter stroke 4 main 170 ( typical @54cc) NOT Recess Piston used in 200/250 (typical@62cc) .
.
DODE and D7DE Closed and Open chambers
. . .
.
'63 'more door' Wagon's C8DE 170 is stock low-miles Maverick block with a D7DE cyl head re-purposed by my favorite machinist:

OEM C8DE Ford 170 cid Inline Six, D7 Cylinder Head . Oversize intake valves/1.50 exh with- silicon springs and HD retainers, . Milled .090 cyl head w/ Steel Shim Gasket. CR= 9.5:1. H/W 5200 - 2.8 series (32/36) progressive 2Bbl carb., Exhaust ¾ siamese port divider, Champion racing spark plugs, Contact Point/Condensor distributor, Diaphragm Clutch. T5 5 speed Overdrive tranny, Short throw Hurst Indy shifter, OEM 3.50:1 rear, Shelby sway bar, Addco rear sway bar , Fabricated subframe connectors / crossmember, Hooker 6601 dual out longtube headers. Shoulder belts front and belts for three in rear, Dual chamber master cylinder, OEM wide-wagon brakes, dual air line rear shocks, 14” wheels & tires, Countersprung Tailgate, Original tube radio , Iconic Jet Age styling cues …
.

.
have fun

 

[Frank]

The Falcon Performance Handbook states that they are successfully using the 1.468" intake valve from a 144 c.i. as an exhaust valve a simple modification because stem is correct length and diameter only seat needs to be cut larger. Stock exhaust valve is 1.38".
Could be an option.
The Handbook also states that back cutting the intake valve also has the same effect as high-lift rocker arms or cam for a fraction of the price.
Also mentions that the 1.50" exhaust valve is a good option.
Just FYI.

1.468" has 13.2% more area than stock.
1.5" has 18.1% more area than stock and 4.4% more area than 1.468".

 

[drag-200stang]

It is my opinion that 1.5 may be too large and maybe hurting flow, But I have no proof. My turbo engine, I used 1.470, I think that the 144 intake valves are the best off the shelf size. It is better to leave some material to work with if you need to redo the valves.
If you cannot find the 144 valves, look into cutting the 1.5 down to 1.468''.
Do the back cut on the intake valves.

 

[awasson]

I can't seem to find a source for 144 intake valves. Anyone have one they can share?

Cheers,
Andrew

 

[bmbm40]

The 1.380" exhaust valve remained in every version of head design from the 1965-1972 890 cc log to the 1980-up 1345 cc log with the larger 1.750" intake valve for the 200 and 250. Of course performance was never a factor in log head design. It would be interesting to know what the 1.467" 144 c.i. intake valve upgrade alone would measure on dyno testing.

 

[bmbm40]

I can't seem to find a source for 144 intake valves. Anyone have one they can share?

Cheers,
Andrew

Take a look at this:

Pardon Our Interruption...

 

[aussie7mains]

There is a suggestion to use intake valves in exhaust applications, this wont last long, intake valves are not very heat resistant and will most likely burn out in exhaust use. Most exhaust valves uses a heat resistance head friction welded onto the softer stem material, intakes are usually one piece. Also here in Australia, the intakes in the early pre crossflow heads were 30 degree seats, exhausts are 45. Ive used Windsor exhaust valves with cut down stems in the pre x heads, way back, worked OK, but I couldnt say how long they would last.

 

[awasson]

I just did some poking around and Vintage Inlines still carries stainless 1.5" exhaust valves. I had no idea that those were still available. They also carry the stainless 1.76 intakes. If those used 144 intake valves weren't more expensive than a set of stainless exhaust valves then that would be my choice. Plenty of members here have attested to the ruggedness of the stock 144 intake and they seem to hold up well (according to posts on the subject).

Here are the stainless valves.

SI Port-Flow 1.76 Intake Valve | Vintage Inlines

Set includes 6 Port-Flow 1.760" Stainless Steel intake valves. Fits all 170/200/250ci cylinder heads. These valves work great for increasing air flow in a stock cast iron cylinder head. Some unshrouding may be necessary on small log heads.

www.vintageinlines.com

SI Port-Flow 1.50 Exhaust Valve | Vintage Inlines

Set includes 6 Port-Flow 1.500" Stainless Steel exhaust valves. Fits all 170/200/250ci cylinder heads. Requires machining for larger valve seats.

www.vintageinlines.com

 

[drag-200stang]

There is a suggestion to use intake valves in exhaust applications, this wont last long, intake valves are not very heat resistant and will most likely burn out in exhaust use. Most exhaust valves uses a heat resistance head friction welded onto the softer stem material, intakes are usually one piece. Also here in Australia, the intakes in the early pre crossflow heads were 30 degree seats, exhausts are 45. Ive used Windsor exhaust valves with cut down stems in the pre x heads, way back, worked OK, but I couldnt say how long they would last.

The US small six use 5/16'' stems and the intake and exhaust are made the same way out of the same material.

 

[aussie7mains]

The US small six use 5/16'' stems and the intake and exhaust are made the same way out of the same material.

Before 66 they used the small stems here, but 11/32 from there, ours are different materials, Im surprised the USA ones are the same, but which material? All the later alloy heads had silicon bronze seats, and were fine even with LPG. They had 11/32 stems, 1.85 and 1.55 on EFI heads, but longer.

 

[drag-200stang]

Before 66 they used the small stems here, but 11/32 from there, ours are different materials, Im surprised the USA ones are the same, but which material? All the later alloy heads had silicon bronze seats, and were fine even with LPG. They had 11/32 stems, 1.85 and 1.55 on EFI heads, but longer.

The exact details of the material used has escaped me.
Long ago when I was looking for a larger exhaust valve at the local auto parts/ machine shop, I came across a John Deere Intake valve in the size head and stem that I needed, it was longer. I have no idea why the 144 valve was not listed with others by size but it was not or I would have used it. The Deere intake valve was Inconel and the stem was hard chromed. Took them to
George DeLorean's Leader Automotive and had him shorten and harden the tip. Yes, John's brother. He asked me Who did the port work. The way he said it I thought that I had messed it up, but he said ''good job''.

 

[DON]

Did you get a hopped up flux capacitor from him???

 

[drag-200stang]

Did you get a hopped up flux capacitor from him???

I wondered why it was a little faster than it should be.
P.S. sorry awasson for the derail

 

[bmbm40]

Take a look at this:

Pardon Our Interruption...

Finally heard from the seller. These are not intake valves for a 144 as advertised. The diameter as he measured is 1.573".

 

[awasson]

Yep, not going to be useful for what we're looking for. Too pricey for old used parts too.