www.the351cforum.com

ALL things related to the Ford 351C
It is currently Sun Nov 18, 2018 10:56 pm

All times are UTC - 5 hours




Post new topic Reply to topic  [ 42 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
PostPosted: Fri Feb 09, 2018 8:12 am 
Offline

Joined: Mon Oct 29, 2012 11:08 pm
Posts: 277
Location: Everywhere !
Why not just run the 2v heads if your going to stay with the small valves?


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 11:38 am 
Offline

Joined: Thu Dec 29, 2016 12:53 pm
Posts: 13
dfree383 wrote:
Why not just run the 2v heads if your going to stay with the small valves?


They are the original heads and block for the vehicle.


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 11:58 am 
Offline

Joined: Thu Dec 29, 2016 12:53 pm
Posts: 13
The Pantera forum seems to like the specs on this Bullet grind.
Advertised 277/277 @ .050 228/228
579/579 lift with 1.73 rockers, 57 overlap


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 12:31 pm 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2416
Pantera forum......

I bet I know who came up with that cam........ :lol:

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 12:32 pm 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2416
BTW, Mr. Robinson, I sent you a private message that has not been read yet. It's still sitting in my outbox.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 3:45 pm 
Offline

Joined: Tue Jun 02, 2015 2:28 pm
Posts: 216
I bet I know who came up with that cam........ :lol:

Hard to say who......Maybe the one cam man?
Who's name we can not speech...


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 4:26 pm 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2416
I said it tongue-in-cheek, because the "discussion" with George Pence about that camshaft on the other forum is what got me kicked off that other forum...........which led me to start this one.

While a brilliant man with historical knowledge of the 351C, George is not an engine builder.

I'm not professing to be a cam expert by any means, but being an engine builder puts me in a spot where I can test all kinds of different products, even back-to-back camshaft tests on the dyno. The Cleveland engine desires a very specific requirement for camshaft specs. Once that requirement is met, then you can tweak the details based on other inputs.

It's a pretty big no-no to use a single pattern camshaft and it's a pretty big no-no to use a wide LSA. I have catalogs of lobes from different cam grinders and it's easy for me to sit down and come up with the perfect situation that will optimize performance but will keep overlap where it needs to be, dynamic compression where it needs to be, etc.

The Pantera boys are good boys and I'm sure that they mean the best. However, most of them have never been put in a position to try one camshaft against another. To be honest, these engines run OK with a lot of cams but unless you've completed an A-B test, you would never know what you're missing.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
PostPosted: Wed Feb 14, 2018 6:47 pm 
Offline

Joined: Wed Oct 31, 2012 11:24 am
Posts: 283
Mr Robinson, I was not going to respond on your build because of the mild nature and simple build it appeared to be. I can't sit back any longer after the cam suggestion from the Pantera forum's "expert". I will politely demonstrate why it is not worth wasting your money on.
The 1973 heads are severely limited by the use of the 2V intake valve in an otherwise 4V head. The air flow is not good after .500 lift. unless corrected by CAREFUL porting and or the use of the 2.190 4V intake valve.
The next part of the problem is simple physics. The intake flow is a totally different "medium" than exhaust flow. Here is an example. Think of intake flow as a lightly rainy day with a breeze. Now look at exhaust flow as an extremely hot , windy day. Trying to move through either requires different preparation. The same is true in camshaft design. For 49 years I have been dealing with the canted valve Ford heads in both race and street engines. I was taught to keep a log of what I ran and how it performed to establish patterns. I learned in the '70s that the head did not respond like an inline 289-302-351W head did. "On my own" I developed theories as to how to make the engine run better through special camshafts. In the persuite I found short duration , higher lift intake lobes , combined with slightly longer duration exhaust lobes that had shorter lift made significant power gains over the 'then" catalog offerings ( pre internet days) . I didn't share my findings for thirty years until "the industry" started making cams in a similar fashion . The "gentleman" from the Pantera forum had never built an engine in his life when I met him at a local car show. While "booksmart" and eloquent , his "hands on " knowledge was non existent. During the hour we talked , he was very gracious but asked many naive questions for someone "posing" as a "guru".
Mr Lykins has given you a very good suggestion which will out perform the single pattern cam suggested. Brent's experience is enough to write his own book for the Pantera expert to read and learn from.
Sincerely,
Randy Gillis ( former Pantera owner and Panters Owners Club of America board member)


Last edited by gt350hr on Fri Feb 16, 2018 1:56 pm, edited 1 time in total.

Top
 Profile  
 
PostPosted: Thu Feb 15, 2018 12:22 am 
Offline

Joined: Wed Mar 22, 2017 9:37 pm
Posts: 6
Not picking sides but one of the cams recommended on that other forum ,for the D3ZE head with larger 2.125 intake valves installed, is this.

"Custom hydraulic flat tappet cam ground by Bullet Cams (lobes HF275/328 and H286/328), spec: 275°/286° duration @ 0.006, 223°/230° duration @ 0.050, 0.559/0.559 net lift, 103°/117° lobe centerlines, 110° lsa, 60.5° overlap, EVO = 81°, IVC = 60.5°. "

I believe the idea behind this cam is to raise the Dynamic compression ratio while keeping the 1973 stock 8.1:1 Static compression ratio.
I don't really understand Dynamic compression but I can wrap my mind around squeezing an air fuel mixture into a smaller space to make a bigger bang. At some point low octane fuel will detonate itself.

Is this cam similar to the one Brent suggested earlier in the thread?


Top
 Profile  
 
PostPosted: Thu Feb 15, 2018 6:12 am 
Offline

Joined: Mon Oct 29, 2012 9:05 am
Posts: 2416
That one isn't bad, but it's got a bit more overlap than I would want for this particular engine because of the lazier exhaust lobe. That can result in less vacuum, although 60° is still pretty low, and it can also change how the cylinder head works.

With an intake valve closing event of 60.5°, it's on a 104 ICL. I don't see a lot of camshafts out there with a 110 LSA and a 104 ICL, so I suspect that you found one of my suggested cams on another forum.

I like the advanced cam timing and I usually try to run them pretty far ahead on street cars. One of the reasons is what you're hinting at, LTP....the DCR.

DCR is dynamic compression ratio and takes into consideration how early or late the intake valve closes before the compression stroke. It's hard to make compression if a valve is open, so if you close that intake valve early, you're gonna boost the cylinder pressure up. Conversely, if you close it later, you're gonna bleed some off.

The other reason for the 104 ICL is that it really affects throttle response and snap. On the dyno, when I use advanced cam timing like that, I usually find myself jetting down because the engines are more efficient....sucking harder on the carburetor, thus needing less fuel for the same result.

Here's my take on camshafts: it's my personal belief that every engine really needs its own personalized camshaft. Even if you have two engines exactly the same and put them in two different cars with different rearend gears, different weights, etc., I think all of that should be taken into consideration and adjusted if necessary.

My biggest pet peeve are universal cams and it cuts me to the bone to look in a cam manufacturer's catalog and see "Works well with 3.50 or above gear" or "RPM range 6000-6500", etc. There's absolutely ZERO way that the cam manufacturer can know exactly where that engine will peak because every single facet of the build will change the operating characteristics. Even porting the heads by 20 cfm will change the cam specs. Changing the intake will change the cam specs. Adding a 1/2 point of compression will change the cam specs.

Do they work? Well, sure. However, the amount of guys who try back to back cam swaps is probably less than 1%. Most guys stick one cam in and that's the way the engine lives for the rest of its life.

The reason for the specialized camshafts for the Cleveland is because of the head design. The 4V port is very large and has low velocity. On the street, you need to get that velocity up and make the air/fuel charge move quicker. You do this with the exhaust side.....it's called exhaust scavenging. You need overlap to do it, because when the exhaust valve is open at the same time as the intake valve, the exhaust charge flowing out the exhaust valve is causing the intake charge to come in quicker. Different valve sizes will require different amounts of overlap. A big, fat intake valve will have more CSA under it, which can hurt velocity. Obviously the valve angles play a role in this too.

A lot of the 60's/70's Ford hipo heads are similar. Look at a 351C 4V head and then look at an FE Tunnel Port head. You will see resemblances.....big ole fat huge ports with low velocity. This isn't an issue at rpm because you have higher velocity at rpm. What gets hurt is low rpm operation, like you would see driving around on the street. You can either adjust the operation with a custom camshaft or you can add displacement, which will pull harder on the intake ports.

On my own 354C build that's outlined in the build section, I had already selected a camshaft but had a "custom cam grinder" email me and ask if I would give him my business. I told him that I was building a Cleveland to play with and if he wanted to send me a camshaft, I would try it back-to-back with mine. I gave him every spec that he asked for, including *my own* camshaft specs....LOL

When assembly time came around, I even mocked up and assembled the engine to favor his camshaft....i.e. his cam was a different base circle, which changes the pushrod length, so I measured pushrods for his camshaft and then just used them over for my camshaft. The different length pushrod with a different base circle will change the rocker arm contact pattern on the valve, which can make you lose lift at the valve. Valve spring pressures were similar, so I let that one ride, and I degreed both cams and found that they would both work with the same crank gear keyway.

Dyno day came and I tried his camshaft first. It made around 587 hp @ 7800-8000 rpm. I had a two piece timing cover, so I just pulled the balancer, pulled the timing cover plate off, pulled the rocker arms off, then took pieces of coat hanger and grabbed the lifter link bars and raised them up....then tied them to the rocker studs. Didn't pull the intake or anything and had my camshaft installed in about 45 minutes.

My camshaft made 615 hp @ 8000 rpm. It made 28 more peak horsepower with less than 200 rpm difference between peak hp rpms, and over 10 average horsepower more. Torque numbers were the same.

These engines just like different ways of doing the camshaft and you just can't apply the same techniques to a Cleveland as you would a Windsor, SBC, etc.

_________________
Brent Lykins, Lykins Motorsports
www.lykinsmotorsports.com
brent@lykinsmotorsports.com


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 42 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group