Advance the cam 4 degrees?

[Alvin in AZ]

My 360FE engine rebuilder swore up and down that advancing the stock
"smog" cam on those old '70's smogged-up engines would give you more
usable power and better gas mileage just using the stock cam.

So, wondering if doing the same... installing a certain timing set in a '91
351w guy could improve the fuel mileage and shift the power band down
to a more usable rpm? (especially for a manual transmission)

1.7 ratio rockers have been recommended to me over on FSB but wanted
to ask about cam timing, here. If I were to mess with the stock cam
I'd want to change the timing first then change the rockers to feel the
effects. (tinkerers like to do things in a silly way like that)

On FSB "Fireguy" Ryan of "Ford fuel Injection" wrote:
- For a good {Speed Density friendly} fuel injection truck cam:
- Intake duration @ 0.50" should be kept at or under 210
- Gross valve lift should be kept under 0.500
- Lobe separation should be at or above 114°
Thread: http://www.fullsizebronco.com/forum/showthread.php?t=6867&page=6&highlight="cam+timing"
...the thread mostly sucks, lots of guys trying to worm their way around
those basic facts. :/ The first post (Ryan's) kicks butt tho!

But how much cam timing change for a '91 351w (125k miles)?
A full 4 degrees or 3 or 2?
Or, skip this business and only get rockers, like I was told? LOL

Alvin in AZ

 

[1985 Ford F-150]

If its a stock cam I wouldnt mess with the rockers (kinda like puttin chrome valve covers on a grease caked motor). As for the timing ya might just try bumpin the distributor up some and see if that does anything.

 

[Alvin in AZ]

Have read it and want to verify... that the ~4 degrees of retard on a
"smog cam" is in reality, all in the timing set? But does that still hold
true for a '91 351w? If so, will a straight up Cloyes set fix it?

-------------------

"1985" thanks for the "try", no kidding, but cam timing or new cam will
be the only answer to my '91 351w being gutless as anything at below
1500rpm. It pulls good and hard at 2000 up.

BTDT with my '75 360FE, a Comp 252/252 fixed that bay right up!
It wouldn't pull from 31 mph in 4th gear, it'd actually slow down. LOL

After the cam change not sure where the "bottom" is. 8mph in 4th
seems kinda rough on things, but feels like it wants to pull, 12mph no
problem. That's not something I use, just an indication of where the
power band is.

None of this is important when you got an automatic transmission.
It really shows up using a manual tho.

Alvin in AZ

 

[flareside_thunder]

1.7 Comp Cams RR's helped my truck out....of course, they're couple with GT40 heads...

 

[Alvin in AZ]

Q: Which years did Ford retard the valve timing on their 351w engines?
Q: Was the timing change entirely in the sprockets?
Q: How many degrees at the cam was it?
Q: Do any of your "non-adjustable" timing sets for 351w have any retarded
timing in them?

A: All of our performance set have straight up timing on them but allow
for advance or retard.
A: Timing was done in the crank sprocket if Ford made use of this.
A: I do not show any listing 351w with retard feature."

Mike Senia
Tech Support
Cloyes Gear & Products, Inc.
Fort Smith, Arkansas

--------------------------

Hmmm... sounds like if I want to advance the timing on the cam I need
to adjust it in, not just rely on a "non-adjustable" timing set to do it?

Alvin in AZ

 

[Alvin in AZ]

1.7 Comp Cams RR's helped my truck out....of course, they're couple with GT40 heads...

Cool. You running a manual transmission?

The '91 351 I want to do this to has 125k on it and I don't expect to put 50k
more miles on it before swapping it out. (got 2 more of the dangged-thangs

But in the meantime, it'd be kinda cool to experiment and maybe improve it?

At this point, thinking a cheap adjustable timing set would be just the ticket.

1.7 ratio rockers might help but when I rebuild one of the 351w's I'll put a
cam in it so the 1.7's won't be needed?

Alvin in AZ

 

[flareside_thunder]

The 1.7's are a cheap way to gain cam lift. if you intend on rebuilding one and swapping cams I damn sure would run 1.6 RR's...stock ratio just more efficient and alot less cam math to do. No, that's on an automatic.