Author Topic: How much do 2.08 CJ valves help over the standard 2.02 valves?  (Read 2907 times)

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FERoadster

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How much do 2.08 CJ valves help over the standard 2.02 valves?
« on: February 17, 2018, 07:18:41 PM »
For a street driven car with an occasional 1/8 mile pass. 3X2 intake, shorty headers, 3.50 gear in a 3400 lb. car. 4 spd wide ratio.
Is the cost of valves possibly seats and the valve job worth it on D2TE heads? Heads already have a new std.valve job.
Werby???
Richard 

My427stang

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #1 on: February 17, 2018, 09:35:42 PM »
Valves alone, not much, especially if you just use them to get to new metal for a sunk seat.

However, if the stock valves are sunk and a wide seat, a modern valve job and nice transition to the bowls could be worth 20+ hp

I probably wouldn't take down a set of fresh heads for a valve swap, but, if you were going to have them ported, even just real nice bowl work too, I'd consider it.

Also make sure you get rid of the 2 piece retainers if you didn't, they're pretty heavy
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

CaptCobrajet

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #2 on: February 17, 2018, 11:57:50 PM »
The OE valve job was so crappy that it would be a substantial improvement.  You can't fix the lack of material with the small valve......no real estate for a modern valve job.  Going to the CJ valves will at least give you plenty of material to get a very good valve job with several bottom angles without dropping off in a hole.  I'd do it in a heartbeat.
Blair Patrick

My427stang

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #3 on: February 18, 2018, 09:04:42 AM »
The OE valve job was so crappy that it would be a substantial improvement.  You can't fix the lack of material with the small valve......no real estate for a modern valve job.  Going to the CJ valves will at least give you plenty of material to get a very good valve job with several bottom angles without dropping off in a hole.  I'd do it in a heartbeat.

Blair, question for you, what kind of hp numbers would you expect?  Of course, not talking the type of iron head work I saw Morgan playing with when I lived in Waldorf, but if you took a set of D2s, worked as much of a transition as you could in the seat with stock 3/8 valves, then dug in with nice valve job as you discuss with CJ valves, what would you estimate for a gain on a 400 hp engine?  I just don't have the dyno experience to answer with a guess

Also, I know he didn't ask this question, but I think I'd pick a better head to stick the money into and swap them if I was going that route. 

Richard, FWIW, in case it sounds like I am saying they aren't good, you don't have to be afraid of the D2s, they can work well especially on a heavy/mild street toy, I have a set of worked D2s that were on my 445 in my F100 and despite the noise I am chasing, it was like a light switch when you hit the throttle.  However, not worked, they don't flow much, 200-220 cfm on a good day.  We did CJ valves and a lot of grinding and mine flow an average of 277 cfm on the intake side (that could support as much as a 100 hp difference), but it wasn't just a valve swap and bowl work, and gets expensive.
« Last Edit: February 18, 2018, 09:20:16 AM by My427stang »
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

JamesonRacing

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #4 on: February 18, 2018, 09:16:06 AM »
What a coincidence...Blair has a set of my D2 heads in his shop right now, though they had already had CJ valves installed a while back.  Will be built for torque/towing, so not really interested in big flow numbers, just gobs of velocity.
1966 Fairlane GT, Silver Blue/Black 496/C4 (9.93@133)
1966 Fairlane GT, Nightmist Blue/Black 465/TKO (11.41@122)
1966 Fairlane GTA Conv, Antique Bronze/Black, 418EFI/C6
1966 F250 C/S, Rangoon Red, 445/T19
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My427stang

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #5 on: February 18, 2018, 09:26:29 AM »
What a coincidence...Blair has a set of my D2 heads in his shop right now, though they had already had CJ valves installed a while back.  Will be built for torque/towing, so not really interested in big flow numbers, just gobs of velocity.

If course the other comment with D2s is having a header to match or use manifolds.  The only reason I went with D2s in my 445 is because it was an easy way to use the off the shelf header I already had coated for the truck.  Truth in advertising, I'd likely go with an aluminum head if I did it again and modify a set of headers, even if they were already coated.  I was still cheaper, and before the BBMs and Trick Flows came out, made more power, but I'd rather have a modern chamber and easier ability to modify the heads later.

Here's a couple pictures to show the difference, I wouldn't consider it critical, but even though the D2 is a little better than earlier heads, it isn't too fancy chamber wise.



« Last Edit: February 18, 2018, 09:29:27 AM by My427stang »
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

WerbyFord

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #6 on: February 18, 2018, 11:57:34 AM »
For a street driven car with an occasional 1/8 mile pass. 3X2 intake, shorty headers, 3.50 gear in a 3400 lb. car. 4 spd wide ratio.
Is the cost of valves possibly seats and the valve job worth it on D2TE heads? Heads already have a new std.valve job.
Werby???
Richard

Well those guys pretty well covered it, better than I could. Blair said it well about the factory valve job. I recently just took a set of bone stock c4ae-g and put a 5-angle valve job on by hand - gained about 10ftlb across the board according to GTECH runs on the street, still the 2.03 x 1.56 stock valves.

In contrast, I had a set of b9ae-b heads (same early casting), 2.09 intakes added but still stock 1.56 exhaust. Whoever did it just did kind of a 1-angle or 2-angle valve job putting the 2.09's in - single 30-degree valve seat, and then things just plunged down into the abyss of the valve bowl. These heads ran SLOWER than a set of stock c4ae-g small valve heads (even BEFORE my fancy valve seat job).

So, "just adding 2.09 valves"? Probably go SLOWER - if anything. All the magic is in the seat/bowl prep as these guys indicated.
Further, it is my and the Gonk's opinion that the weak part of stock FE heads is the exhaust side, not the intake side - so unless you already have 1.66 exhaust's in there (like Ford did on the 406 before the bigger intake) I would not go w bigger intakes.

And if its a small bore (say under 4.08) I wouldn't go bigger valves at all, just get the best finish you can on the 2.03 x 1.56 valves.

I have done BOTH, also by hand with the Neway cutters mainly - 2.09 intakes with 5-angle seat, 1.66 exhaust with 5-angle seat, blended into the bowls, port exhaust roofs. The result feels like a bigger cam - no gain down low, about the same at 3000, then BAM, about a 25hp gain up high at 5000-5500 per GTECH vs the stock c1ae-a or c4ae-g heads. Well worth it but a lot of time and metal chips on the kitchen counter (Werbys Wife is so patient!). Those shiny new aluminum FE heads may be a better way to go than sinking big $$$ or time into the old iron unless class racing demands it.

CaptCobrajet

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #7 on: February 18, 2018, 12:26:37 PM »
I think with 3.50 gears, and a 4-speed......in a 3400 lb. car, that current aluminum offerings are hard to beat.  I have David's 445 here as he mentioned, and also a 464 for another pull/tug/tow truck.  I think the D2 with the right touch still may be better when they are in the meat between 2000 and 3500 rpm.  The small port, short duration idea is king right there.  Flow as much as you can at low lift and don't overdo it on duration.

For the car application described above, a willingness to cam it right and approach 6000 rpm, there would be a much better result from modern aluminum.

With that said, I can get 270-ish numbers out of a D2 with a good valve, valvejob, and light work in the right places.  A person can get to 500 hp with iron for the street.  The chamber in the C8/D2 is better than a G or R head, but the ports are better in those to start with......

Ross......hard to give it a definite value without a back-to-back test, but 40-50 cfm is huge IF the demand is there in the subject engine.
Blair Patrick

scott foxwell

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Re: How much do 2.08 CJ valves help over the standard 2.02 valves?
« Reply #8 on: February 18, 2018, 08:22:52 PM »
FERoadster...how big is your engine and what rpm are you planning on running it? That's going to dictate more about your valve size and the valve job than anything. A 428 doesn't "need" a 2.08 valve if it's only going to turn 6000 rpm, but that really depends on the size of the throat...the hole in the head, not the actual diameter of the valve. As Blair said, the real benefit may be in a better valve job and gaining some airflow. If you don't change the throat size along with the valve diameter, the increase in valve size really won't change anything as far as a "bigger valve" is concerned. For my 390 I went to a 2.05 with my C6AE H heads but not because the engine needed the bigger valve, but ONLY because that's what it needed for a good valve job. The throats were already bigger than they needed to be for the stock valve which would have been plenty big...as far as the math goes. It's all about the velocity through the throat and keeping it in a certain range to maintain good cylinder filling.