Go Back   Ford Truck Enthusiasts Forums > Performance, Engines & Troubleshooting > FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
Sign in using an external account
Register Forgot Password?


Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #31  
Old 04-26-2007, 12:18 AM
rusty70f100 rusty70f100 is offline
Post Fiend
 
Join Date: Jan 2003
Location: Iowa
Posts: 8,600
rusty70f100 is gaining momentum as a positive member of FTE.rusty70f100 is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by obey_your_master
What do you guys think about a stock profile cam of that of a 390GT/428CJ,SCJ? Someone told me that this is a great cam to use for mileage and all around street performance. Just looking for a cam that will run in a 9.5:1 compression 390, D2TE-AA heads, four barrel induction and headers in a small half ton 2wd truck.
I dont really know, maybe it would. Chances are it would work ok. However, there are many excellent alternatives from Crane and Comp that are 30 years newer. Unless you're looking for the absolute cheapest, safest way of doing things, and are sure the stock cam is in good shape, I'd look at a modern aftermarket cam and valvetrain.
Reply With Quote
  #32  
Old 04-26-2007, 12:51 AM
Alvin in AZ's Avatar
Alvin in AZ Alvin in AZ is offline
Postmaster
 
Join Date: Aug 2005
Location: Gadsden Purchase
Posts: 2,760
Alvin in AZ is gaining momentum as a positive member of FTE.Alvin in AZ is gaining momentum as a positive member of FTE.
Quote:
Originally Posted by obey_your_master
rusty, maybe you should write books on this stuff cause that was first thing that I have understood all week
Yeah! :)

"Sorry for the book"
=equals=
"sorry for writing something worth reading"
Huh? :)

And didn't even think of Rusty's last reason, not to get a 260/260 "RV cam" for my stock 360FE (2100 2v, single straight thru-2+1/2" exhaust). Was just thinking in terms of power band when i went with the measly little ol' 252/252 "economy cam". :)

The fact that the 252/252 had bigger -bumps- on it than a new stock cam sounded good enough to me. :)

Also the fact that i couldn't even -buy- a transmission speedometer gear to fix the odometer shows that 3.25 gears and 31.5" 235/85-16's weren't inside anyone's RPM planning.

Alvin in AZ
Reply With Quote
  #33  
Old 04-26-2007, 01:45 AM
"Beemer Nut" "Beemer Nut" is offline
Post Fiend
 
Join Date: Dec 2003
Location: "Islander"
Posts: 6,658
"Beemer Nut" has a good reputation on FTE."Beemer Nut" has a good reputation on FTE."Beemer Nut" has a good reputation on FTE.
obey; the 390GT/428CJ cam is 270/290 w/194/204 @ .050", .481"/.490" lift, 46* overlap. Yes it's a old cam grind looking at the lazy .050" numbers, it doesn't slam the valves open like modern cams allowing for low valve train wear and high mileage. I'm over 249K, 3.54's w/33.5" 12.00's with a custom low stall converter, can turn tires at will plus 15 mpg if driven carefully.
A 410 build, to do it over again I would use another OEM CJ in a hot second as this is a daily driver not a Chevron profit maker.
__________________
.....=o&o>.....
Reply With Quote
  #34  
Old 04-26-2007, 06:33 AM
scottlane's Avatar
scottlane scottlane is offline
Senior User
 
Join Date: Jun 2003
Location: Ousley, GA
Posts: 282
scottlane is starting off with a positive reputation.
I agree. Excellent postings. Glad I started this thread and it was hijacked in this direction. It's been an education. Shamed me into not even considering putting the old cam back in for the rebuild!
__________________
Two wrongs don't make a right but 3 lefts do.
Reply With Quote
  #35  
Old 04-26-2007, 08:50 AM
dbossman dbossman is offline
Senior User
 
Join Date: Aug 2003
Posts: 241
dbossman is starting off with a positive reputation.
Talk to Barry Robotnik

at survivalmotorsports.com. He is/was one of the site sponsors I believe.

He offers a cam that is one notch above the 390GT/428CJ cam. Its 204/214 duration at .050 and 484/510 lift.

I am using one in my 428 with factory style adjustable valvetrain. Its certainly a mild cam, but I really like it. It runs real strong.
Reply With Quote
  #36  
Old 04-26-2007, 10:33 AM
Krewat's Avatar
Krewat Krewat is offline
Super Moderator
 
Join Date: Jul 2002
Location: Long Island USA
Posts: 34,583
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
Quote:
Originally Posted by scottlane
I agree. Excellent postings. Glad I started this thread and it was hijacked in this direction. It's been an education. Shamed me into not even considering putting the old cam back in for the rebuild!
You mean for once, wasn't a BAD thing?!?!?!?

__________________
- art k. - Moderator for the Superduty, V10, 6.2L and FE forums
'13 Taurus SHO 3.5L Ecoboost w/Perf Pkg
'01 F250SD SC SB XLT V10 4x4 Volant CAI Hedman headers 5-star custom tunes on SCT X3
'97 Cougar XR7 30th Anniv Edition 4.6L
'74 F250 Highboy FE390 deceased!
I've been wrong before, I'll be wrong again. Just wait and see. ®
Reply With Quote
  #37  
Old 04-26-2007, 10:45 AM
scottlane's Avatar
scottlane scottlane is offline
Senior User
 
Join Date: Jun 2003
Location: Ousley, GA
Posts: 282
scottlane is starting off with a positive reputation.
I think it was a good thing!

Now I need to get someone to explain to me how much I can benefit from an adjustable timing set put in a rebuilt 390 with the Crane 343901 cam. Daily driver.
__________________
Two wrongs don't make a right but 3 lefts do.
Reply With Quote
  #38  
Old 04-26-2007, 11:04 AM
acheda's Avatar
acheda acheda is offline
Elder User
 
Join Date: Feb 2004
Location: San Luis Obispo, CA
Posts: 909
acheda is gaining momentum as a positive member of FTE.
Scott,

My experience is in post #10, but maybe I should state clearly that my truck was a driver, not a racer, and did a lot of towing too. It was fun to drive with or without a trailer. It had good torque and good acceleration.

Have fun & let us know how it runs.
__________________
Archie - w[size=1]orking on Fords since '63
Reply With Quote
  #39  
Old 04-26-2007, 11:36 AM
rusty70f100 rusty70f100 is offline
Post Fiend
 
Join Date: Jan 2003
Location: Iowa
Posts: 8,600
rusty70f100 is gaining momentum as a positive member of FTE.rusty70f100 is gaining momentum as a positive member of FTE.
Oh boy, here we go again!

First, the adjustable FE rockers have a 1.76:1 ratio, as opposed to the non-adjustable 1.73:1 ratio. Now that's not a very big difference, and you'd likely never notice it, but you will get slightly more power with the adjustables.

Second, is the adjustability! But before we can appreciate that, we must know how hydraulic lifters work. Basically you have a plunger and a check valve. This can either be a ball or disc. There is then a spring which tries to push the plunger out of the lifter. This is what makes a lifter with no oil in it springy (you can compress it and it rebounds back). In a running engine, the lifters are exposed to oil pressure. The oil naturally flows into the lifter, displacing the air that was there. Thing is, oil isn't compressible like air. So when the lifter is on the base circle of the cam, the oil flows in behind the plunger, with the spring helping, pushing up on the plunger and taking up all the play in the valvetrain. This is what makes a hydraulic lifter motor so nice and quiet. Essentially, it's like a solid lifter at zero lash.

But there are things that can go wrong. The little check ball or disc can leak, causing a noisy lifter. Or, the lifter can pump up with oil at high rpm, leaving the valve off it's seat when it should be closed. This can have bad consequences. The reason this happens (IMO) is because of valve float. The valve spring at high rpm no longer has enough force to close the valve when it should according to the cam lobe, and the valvetrain becomes loose. The lifter sees this and expands to compensate, but instead is now expanded too far and leaves the valve open.

Another conecpt to understand is the relationship of preload to lifter pump up. Lifter preload is how far the plunger is pushed down in it's bore when the lifter is on the base circle of the cam. The more preload, the more force the spring in the lifter is exerting on the plunger, and the more the lifter wants to take up any slack. This is good for a low rpm motor that never sees any valve float. But on a higher rpm motor, you want a minimum amount of preload. Most of us with adjustable rockers go 3/4 to one turn after taking up all the slack in the valvetrain, to preload the lifters. Of course that number is up for debate, and some guys prefer to directly measure the preload. To each his own.

Which brings us back to adjustable rockers. In the non-adjustable system, you have no way of accurately setting the preload short of a custom pushrod for each valve. Basically the best you could do on a budget is measure all of 'em at zero lash, take an average, add your desired preload, and order your custom pushrods. But even then, you'll end up with some with too much and some with too little preload. It's a losing proposition. With adjustables, you simply get the rockers, your matching pushrods, and adjust as described in the last paragraph. Nothing custom, and preload set accurately on all lifters.

Some guys have had problems with over-oiling in the top end with adjustable rockers. I suspect this is because the rockers themselves are designed differently and let more oil out. So you need the 3 finger oil baffles to keep that under control.

Does that help?

Last edited by rusty70f100; 04-26-2007 at 11:40 AM.
Reply With Quote
  #40  
Old 04-26-2007, 12:17 PM
scottlane's Avatar
scottlane scottlane is offline
Senior User
 
Join Date: Jun 2003
Location: Ousley, GA
Posts: 282
scottlane is starting off with a positive reputation.
Kurt, you've got this stuff down, brother. Lots of good info.

When I spoke of adjustable timing in post #37 I was referring to the timing gear and how someone like me with a daily driver can benefit from an adjustable timing gear set as opposed to a non-adjustable timing gear set.
__________________
Two wrongs don't make a right but 3 lefts do.
Reply With Quote
  #41  
Old 04-26-2007, 12:38 PM
acheda's Avatar
acheda acheda is offline
Elder User
 
Join Date: Feb 2004
Location: San Luis Obispo, CA
Posts: 909
acheda is gaining momentum as a positive member of FTE.
Kurt, please do not over-react, I agree with 99% of your well-written post.

I wonder if the very light springs in the lifters seriously affect much in the valve train. I think the springs are there to keep the newly installed lifters in the extended position during assembly while the are filled with air.

The way I understand the principle of anti-pump-up lifters is that what you refer to as "preload" is set to the top of the lifter stroke so that pump-up is limited to little or none. The hot-rodder can live with running on the edge of having a little rocker noise as a trade-off for avoiding pump-up.

I have been told (perhaps incorrectly) that the main difference between anti-pump-up & stock lifters is that they have a more robust clip at the top of the lifter bore because it has to act as a stop to limit pump-up. (The clips in stock lifters really only are there to keep the lifter together until it is in the engine.)

I am ready to be educated if I have understood this incorrectly. I have never personally used anti-pump-up lifters, but I worked at an engine rebuilder and we did put them in some applications at customer request, so I have handled them many times. (There may be minor, but important internal differences, but the robust clip is the one obvious difference.)

P.S.: It occurs to me that anti-pump-up lifters could have lighter internal springs . . .
__________________
Archie - w[size=1]orking on Fords since '63
Reply With Quote
  #42  
Old 04-26-2007, 01:04 PM
scottlane's Avatar
scottlane scottlane is offline
Senior User
 
Join Date: Jun 2003
Location: Ousley, GA
Posts: 282
scottlane is starting off with a positive reputation.
Correct me if I'm wrong here, but I seem to remember reading somewhere that adjustable lifters really come into play when you have a cam with a .533 and over lift. Not that they don't/won't work or be beneficial for valvetrains with smaller lift amounts - just not as critical? Am I right about this?
__________________
Two wrongs don't make a right but 3 lefts do.
Reply With Quote
  #43  
Old 04-26-2007, 01:10 PM
acheda's Avatar
acheda acheda is offline
Elder User
 
Join Date: Feb 2004
Location: San Luis Obispo, CA
Posts: 909
acheda is gaining momentum as a positive member of FTE.
More is more & you get the gains of adjustibility. (The numerical increase will be bigger with a bigger lift, but everything will be gaining the same percentage.)

Anybody got info on the inertial differences? I always wondered if the fixed rockers had an rpm advantage. Not only is the rocker likely to be heavier, the cup end of the pushrods look like they might be adding to the valve-train mass.
__________________
Archie - w[size=1]orking on Fords since '63
Reply With Quote
  #44  
Old 04-26-2007, 04:08 PM
rusty70f100 rusty70f100 is offline
Post Fiend
 
Join Date: Jan 2003
Location: Iowa
Posts: 8,600
rusty70f100 is gaining momentum as a positive member of FTE.rusty70f100 is gaining momentum as a positive member of FTE.
Scottlane:
You would benefit from an adjustable timing set by being able to correct for any advance / retard that may have been ground into the cam itself. If there is none, then of course there would be no benefit. But with a stock cam, I suspect that there is. At a minimum use a degree wheel and make sure.

Acheda:
Yes, the spring in the lifter helps with assembly too. I suspect that in a running engine the lifter would function just fine with no spring, as oil pressure would take over at some point. But in an idling FE with 10psi or less oil pressure, I think the spring there helps.

Lifters also do something called "bleed down" over time. What this does, is oil eventually escapes the lifter through the check ball / disc. This also helps with lifter pump up, as it will allow an over extended lifter to come back down to proper adjustment quicker. I think this is what they do with "anti-pump up" lifters. They just bleed back down quicker. They may also have a lighter internal spring, although I'm not entirely sure on that one.
Reply With Quote
  #45  
Old 04-26-2007, 04:21 PM
acheda's Avatar
acheda acheda is offline
Elder User
 
Join Date: Feb 2004
Location: San Luis Obispo, CA
Posts: 909
acheda is gaining momentum as a positive member of FTE.
Kurt,

I had suspected that bleed-down rates might be higher with the anti-pump-up. You do not mention it, but am I correct that the main point of anti-pump-ups is to run them at the top of their stroke?

P.S.: Good point on the 10 psi - it is acting on a pretty small area, so there might need to be some help. I agree with your description of how a floating valve allows the lifter to over-compensate, but it seems that the main defense is to limit this mechanically by working against the clip.
__________________
Archie - w[size=1]orking on Fords since '63
Reply With Quote
Old 04-26-2007, 04:21 PM
 
 
 
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
360 cam/ timing questions cowboyfordlord FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 8 03-21-2013 11:45 PM
390 Rebuilt mlevario99 FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 13 02-06-2008 10:35 AM
desktop dyno request 7FORD2 FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 42 03-11-2007 10:36 PM
Comp cam vs. Crane freejay FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 15 08-29-2003 10:57 PM
Machining question,cam installation Rat wagon FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428) 2 03-17-2003 12:35 PM


Go Back   Ford Truck Enthusiasts Forums > Performance, Engines & Troubleshooting > FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)

Tags
343901, 343902, 360, 390, big, cam, camshaft, crane, crane343901, duration, factory, fe, ford, lift, stock, towing

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump


Participate In The Forums

Create new posts and participate in discussions. It's free!

Sign Up »





All times are GMT -5. The time now is 04:41 PM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Advertising - Terms of Use - Privacy Statement - Jobs
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. Ford® is a registered trademark of the Ford Motor Company.

vbulletin Admin Backup