Ok, Ill try to explain this best I can.

Ever sense I've owned this truck its been making a taping sound, not really a ping or a knock but similar. Seemed to be coming from the passenger side valves, so I pulled the cover everything looked good and oil was flowing up threw all the push rods normally springs etc... Next, tried seamonkey in the oil/gas thinking it was a sticky valve or lifter but seemed to get worse. Next with a small piece or garden hose I started probing around with one end up to my ear. I could hear this noise most clearly from the carb EGR plate. I read something about a heat riser porting air accross the manifold during warm up, but after not finding a heat riser or similar device on my truck, I was starting to think it had to be a lifter.. My last chance was to block off the EGR plate in the back where the valve with the vacuum line connects. Not really thinking this was an issue considering the valve seem in good condition, so I just did a quick patch with a piece of gasket to stop air flow threw the back of the plate. And like magic the taping/ping like noise is about 80% gone To maybe clearifly this noise, when i rev the engine the noise is for the most part gone, but while the rpm's are dropping back to idle the noise is at its worse, and at idle the noise is also pressent.

The question is whats going on inside the intake manifold making this noise. Im guessing its something to do with the crossover EGR system, maybe a valve of some sort.

Id like to keep my EGR system working if possible, Any insite?

 

Dose the factory intake manifold have a liner? Ive seen some intake manifold gasket kits have a liner and some dont. Maybe the air flow is causing the liner to make the noise, and by blocking air flow threw the EGR plate reduces this. Im still getting alittle noise from it, but it night and day. so nice now to be able hear my engine.

 

You don't say what engine you have but I suggest removing the carb & EGR and then
investigating. You'll have to replace some gaskets but they may need replacing by now,
anyway. A hand-operated vacuum pump will help you verify if the diaphragm & valve
actually work....

 

Oh, its a 1985 FORD F-350 PICKUP V8 7.5 Liter 4BBL, its in my signature at bottom of the post.


I sealed off the egr valve its like its not even attached to the plate anymore, so its not that, and I just rebiult the carb 2 days ago (new gaskets under the egr plate aswell). What im saying is the egr port on the manifold has no place to go (its now blocked), and this must have restricted air flow threw out the egr system. The air flow threw the egr system must have been what was making the noise because its all but gone now (which makes me very very happy), but the question is now wth is it making the noise. I was thinking maybe there is some sort of valve inside the manifold maybe to prevent back pressure or something, and the valve has gone bad and flopping around when air flows threw the egr crossover ports. note: I have no clue whats the egr crossover even dose or how it works thats why i asking.

 

Quote:

Originally Posted by Swatter

Oh, its a 1985 FORD F-350 PICKUP V8 7.5 Liter 4BBL, its in my signature at bottom of the post.

I don't display any sigs or avatars at all; if the information isn't in the post, I
won't see it.

Quote:

I sealed off the egr valve its like its not even attached to the plate anymore, so its not that, and I just rebiult the carb 2 days ago (new gaskets under the egr plate aswell). What im saying is the egr port on the manifold has no place to go (its now blocked), and this must have restricted air flow threw out the egr system. The air flow threw the egr system must have been what was making the noise because its all but gone now (which makes me very very happy), but the question is now wth is it making the noise. I was thinking maybe there is some sort of valve inside the manifold maybe to prevent back pressure or something, and the valve has gone bad and flopping around when air flows threw the egr crossover ports. note: I have no clue whats the egr crossover even dose or how it works thats why i asking.

I don't know the specifics of your 460 engine but, to my knowledge, there are
no valves internal to the manifold anywhere. Some earlier engines (335-series)
utilize exhaust gas crossover through the manifold to help with getting the carb
to operating temperature quickly, the EGR system taps into that flow.

The EGR system merely takes a small quantity of exhaust gases and feeds 'em
back into the intake manifold under certain conditions (the emissions tester
guy I go to says we have California to blame for this, too).

My personal suspicion is still a leak someplace, but this is because I
experienced something similar while adapting my 400 to have a 4V manifold &
carb, the leak was between the manifold & EGR plate (hence my suggestion to
take it all apart and investigate).

 

ctubutis, I believe you are thinking of the internal intake manifold heat port to the floor of the plenum. (it is present even in my '87)

Swatter,
Don't you have the crossover pipe linking the back of both heads to the check valve?
These often rust out and cause symptoms just like you describe.
(Sorry for the blurry cellphone image, but you can see the pipe joining the heads and passing behind the oil pressure sensor)

 

Thank you, that summarize what im getting at. I was thinking that maybe my truck at one time had a heat riser attach to the driver side exhaust manifold or simmilar type system, as i understand they port driver side exhaust back threw the intake to warm the carb and then out the passanger side. I'll check for leaks next chance i get, but dont think there are any around the crab, or egr plate.

 

Ok, neighbors hate me, now.. lol I just ran out to check (hood is very hard to open), and oddly ive never seen them back there but yes I have them, and yes the feel rusted out from what i could tell.

 

Thats a nice looking engine you have there, you have a project going on?

 

The "turkey pan" intake manifold gaskets are meant to keep oil in the lifter valley from cooking onto the bottom of the intake manifold's heated floor.
Yes, there is an exhaust gas crossover in the intake manifold.
You can see the center port in the heads of rbalsinger's posts.
Let me find it....

 

I killed my engine in the winter of '08 and made a Flickr set to share with the forum. You can see it here: http://www.flickr.com/photos/2418373...7604137164980/

(comes in handy, no?)

 

I didnt pull the heads, but those 2 push rod tubes looked the same on mine (from the top looking down) passenger side.

 

It's not the push rod tubes, it's 20+ years of old oil on hot metal causing the carbon you see in the photo above.

 

Nice, you kept it mostly stock, smog and all i love it!!

 

On mine it migrated up the tubes and the push rods could hardly move.. it was getting tight in there..lol


anyways, Im going to take a better look at those crossover pipe first chance i get.. cant seem to find any info on them, maybe I can remove and patch, if needed.

Thanks for the info