I just wanted to say Hello, also needing some expertise.

Truck is 1985 460 automatic. The truck runs but the water temp is past the 3/4. I checked the timing and with the vacuum hose still connected it read 3 to 4 deg BTDC, pulled the vacuum still read same. I tried feeling for vacuum suction on the hose and none indicated. Trace the hose and its connected below the base of the carburetor. By the way the carb is a 4180c with gutted emmission. I think the high temp is related to the timing being wrong.

My plan of teeing from the brake booster vacuum line to feed the Vacuum advance to the distributor. Is this going to work? Also my distributor is stuck to the manifold. Please help.

Thanks

 

Welcome to the forum xr-guys!

I'm sure the temperature is being affected by your lack of advance.
Have you tried checking for vacuum with the throttle slightly open? (timed vacuum)
Have you tried using a vacuum pump to see if the advance mechanism is working at all?
Have you checked for TDC #1 to make sure the balancer marks haven't slipped?

Personally I wouldn't disturb the booster line at all.
It's just too safety critical.
There should be two 'taps' for intake manifold vacuum.

One 'tree' in the rear where the vacuum booster connects
http://www.flickr.com/photos/24183730@N03/2341125584/http://www.flickr.com/photos/24183730@N03/2341125584/ by http://www.flickr.com/people/24183730@N03/, on Flickr

And one in the front just behind the distributor (into the 1&6 runner)
http://www.flickr.com/photos/24183730@N03/2340292833/http://www.flickr.com/photos/24183730@N03/2340292833/ by http://www.flickr.com/people/24183730@N03/, on Flickr

The rear connects to the cruise control and the climate controls as well as the brake booster. So, if you don't have cruise there is a spare port there...

The front one to the thermo valves atop the thermostat housing and to the charcoal canisters, if you still have them.

Your distributor doesn't touch the manifold.
It bolts down to the front of the block, as can be seen in the second photo.
Try soaking the base with some penetrating oil (like PB Blaster) or ATF thinned with acetone.
Tapping on the boss where it enters the block with a brass drift will sometimes help free it up.

 

This is what happens when somebody guts the emissions system without considering the consequences. The vacuum supply line should be hooked up to a MANIFOLD vacuum source and the timing should be set to 8-10 degrees with the vacuum hose disconnected....I hope this helps.

 

guys,

thanks for the quick reply!

I just recent got the truck from the 2nd owner with 105K miles. Not sure who actually gutted the emission. So many parts missing to return it back on its original state.

Moving forward, the simplier it is the less things to break, i think?

Jim's pictures really help. All of the vacuum lines from the top of the thermostat are all gone, although the thermo switch are still there just not sure if it is operational. It will be convenient if i can tap right at the front behind the distributor, i'll check on that.

I'm soaking the base of the distributor with WD40, probably heat cycle it a few times. Also will find a vacuum pump to check the circuit.

Jim can you explain the (timed vacuum) how is done?

Will let you know what progress.

Thanks

 

"timed" vacuum is a port just above the throttle blade.
So you see highest vacuum just off idle but no vacuum at all with the throttle closed.
This is why I asked if you had vacuum if you revved it up.
The stock distributor is tuned to work with full manifold vacuum anyhow, so it's best just to find a source of that, IMO.

 

Jim,

I made some progress today. I was able to address the Vacuum Advance on the distributor. Somehow the front manifold vacuum port was intensionally plug. Went to local parts store got something that work with the extra billing (chromed part).

The second accomplishment is i was able to free up the distributor. I have to tap hammer the little tab below the distributor body toward the driver side then use a right angle pry bar pushed against the valve top cover to rotate back to the original position using the same tab. I went back and forth doing this technique until loose. The WD40 spray in between helps.

One issue that i was hoping to also address is the water temp. The temperature is still on the 3/4 mark. I have to mention that the thermostat is a 195. I checked the water temp using laser monitor pointing to the metal solid tube just above the water pump and measured 198 deg F. Is this normal? Should i use a cooler thermostat? Another think i need to mention is my fan shroud is missing 3/4 of it. Because of it I do not think the fan is getting utilized efficiently?


thanks,
Xr

Thanks

 

If you have a 195* 'stat then 198 is perfectly normal.
I don't think you need a cooler one, though usually you'd find a 180* on a carbureted model, it may be that the P.O. wanted better heat in the winter.
(I don't know from your profile where you live)

You really should have a functional radiator shroud.
If 3/4's is missing you will have cooling problems at low speeds when it is very hot out.

Your sender may be giving you a bad reading.
They are cheap enough to just replace.

 

From the factory it would run on ported vacuum during normal operating conditions, but manifold vacuum does work. It helped my truck run better right after starting it up. I actually think the typical factory configuration would work the best, full manifold vacuum below 130F and ported vacuum above 130F

 

Unless the 460 is different from every other Ford engine I have seen, the vacuum advance would have been connected to ported vacuum from the factory.

I knew the Ford Mustangs used a vacuum switch that connected the vacuum advance to full manifold vacuum below 130F and then switched to ported vacuum above 130F, but I have never seen an F150 set up like this. Where was the vacuum switch located?

 

I was going to say are you guys sure the dist on this engine goes to full manifold vacuum, since most Fords use ported vacuum(no vacuum to the dist at idle). You can run it either way and try it, but I never had good results running manifold vacuum to the dist with a automatic transmission. Try it, and you will quickly find out what I am talking about. A manual tranny truck may work ok with full manifold vacuum.

 

You're exactly right, Franklin. I have never had good results with running full manifold vacuum at idle either, especially if the vehicle has an automatic transmission.

I don't really understand why you would even want full vacuum at idle. That would mean you would have more vacuum when you are standing still and at idle, and less or no advance as the engine is under a load. Isn't that backwards? What would be the reason to run full vacuum at idle?

 

You are correct, that is correct that the Holley 4180 equipped Mustang is setup like this. I just assumed that some truck applications used a similar configuration too, because I have read of others saying that some of these trucks had the distributor running to a vacuum switch. Regardless, I think that configuration would work great on my truck anyway.

I think I know what you're saying about the Auto, during deceleration the vacuum goes way up so the distributor pulls full vacuum advance; so you decelerate slower. At least that is my experience.

A lot of timing improves the idle quality when using an aftermarket cam. I probably should have mentioned that before, I don't think there is a benifit on a stock engine. I should post a video of my engine one of these days, showing how much it smooths out when you connect it to full manifold vacuum.

 

Show me, where???

http://www.flickr.com/photos/24183730@N03/2340584591/http://www.flickr.com/photos/24183730@N03/2340584591/ by http://www.flickr.com/people/24183730@N03/, on Flickr

"E" is ported, and connects to the EGR.

Though I don't know how this relates to the OP's '85, I DO know my sticker is accurate for '86&7 trucks over 8500 GVW.

 

Hmmm... looks like in that diagram, at one temp they run a restricted manifold vacuum, and at some other temp they run full manifold vacuum.

 

That's how I read it too. It appears that his ported source is used for other things. You learn something new every day...

Here is a 351W HO vacuum diagram, showing the distributor being run directly to the ported vacuum source on the carb: