Help... Ford 460 Timing Problem
Rick Brewster
David Hellyer wrote:
>
> Please help. I have a 1979 Ford F100 truck. The truck has a 460
> engine. Aluminum intake, and a competition Cams 280H. 280 duration.
> 530 lift. and a Holley 750 double pumper. The timing is set at 20deg.
> BTDC. The truck runs strong but I can not get it to cold idel at all.
> If the camshaft was one tooth off would this cause the idel problem
> and the 20deg BTDC? I've been told that the timing is way to high.
> What are other possible problems that could cause these symptoms.
> Thanks in advance for your help.
> David.
I have a '73 F100 with a '78 460 in it. same cam with an Edelbrock
Perfromer RPM intake and a Holley 3310, 750 CFM vacuum secondary. Very
similar rig. 20 degrees initial sounds a bit much, I run 14 degrees.
Do you have a manual or auto trans? If you have an auto you will not
have very good idle charactistics if you also have a stock torque
converter.I have a C-6 and it idles fine in neutral or park but is very
reluctant to do so in any of the gears when cold. The reason is due to
the fact that the cam allows very little vacuum at idle with a stock TC.
You really need a minimum of 2000 rpm TC for good operation with that
cam and 2800 would be even better. Even with a manual tranny, the lobe
centers are pretty close with that cam to expect a reasonable idle when
cold. I dont mind myself, when warmed up the truck runs like a scalded
ape as more than one Mustang 5.0 or Z-28 Camaro has found out at
the strip, (mine is also lightened to less than 3800 lbs).
David Hellyer
P. J. Remner
That's a pretty wild cam for a truck. Along with a 750 *double pumper*?
Sheeit, I hope you have 5.14's in your rearend!
That's probably the cause of your cold-idle problems. My friend has a
280 cam in his car, he eventually have up trying to get it to cold-idle
and simply threw a chokeless race carb on the thing. Just as "easy" to
start in cold weather, and he doesn't drive it in the winter anyway.
--
The "." in addresses is a delimiter just like a decimal. It's a POINT!
"Assimilate *THIS*!"
Irrational is in the mind of the observer. - Worf
Detroitjoe
I would lean toward your distributer being one tooth off to account for
the high timing. I run 10 BTDC and it will purr. Check the spark plug
wires to ensure they are firing in the right order, especially # 7 & # 8.
They fire one after the other. I would also look for a vacuum leak to
solve for the rough idle. Spray some WD-40 around the base of the carb,
The vacuum lines, and intake manifold while its running. If the engine
picks up RPM then you can bet that you have a vacuum leak. I hope this
helps....
Rick Brewster
> That's a pretty wild cam for a truck. Along with a 750 *double pumper*?
> Sheeit, I hope you have 5.14's in your rearend!
> snip
> --
> The "." in addresses is a delimiter just like a decimal. It's a POINT!
>
> "Assimilate *THIS*!"
> Irrational is in the mind of the observer. - Worf
Ahh, it aint that bad, I have the same cam in a 460 powered 73 F100 with
3.90's in a detroit locker (30" tire dia) with a 750 cfm Holley and
it works fine for street use, including towing my boat, and bracket
racing. But... yer right about one thing, it wont idle when cold without
a lot of throttle foot finese.
Rick Brewster
mat...@ebmud.com
of advance on the pulley and it still won't run. Even with the lift the cam
shouldn't be that radical.
PA...@massey.ac.nz
I missed the first part but heres my bit:
Several things to ensure:
You must find out if the cam is ground for the 0 degree position or the
6 degree retard found on all the 460's from 1974 (I think) onwards.
These two mismatched can throw you way out.
Even just advancing the stock cam gives a boost !
An after market gear and pulley set will fix you up.
Next make sure the lifters are in the centre of their travel.
If not you can guarantee a rough engine. I think a Chiltons will show
how to check this.
Its easy to go wrong especially with different cams, lifters, machined blocks and
heads.
A 750 Holley without secondary jets (only a metering plate)
runs lean on a hot BB, especially if you have headers and worked heads.
A spacer under the carb makes a huge difference. On one engine I lost
1500 rpm but picked up gobs of torque just by removing the 1" spacer.
This was with a 242 degree cam (.o50) and auto.
Good luck.