Exhaust manifolds are toast....................

[Limestone66]

Good morning to all. The exhaust manifolds on 'Limestone' is toast, particularly on the drivers side and bolted to the same head that had gave me all the problems to begin with. My fault for not changing them out when i had the chance whilst it were down, now i lost compression in number 7 cylinder, wont know for sure until we pull it off but i ran a compression test on that dead cylinder and its about 35 pounds to 45 pounds when you turn it over. Gonna pull the head and see whats up. Looking for a good set of long tube headers that will fit the 352/390 in a 66 F-250 and replace those exhaust manifolds. Anybody running headers on the 352? Would there be clearance problems? Also, would the stock thermactor exhaust cause any problems if defective? Man i just had those heads completely rebuilt three months ago, and now this. Any help on this would be greatly appreciated.

[BarnieTrk]

Ron,
Why are you blaming the re-conditioned heads on the loss of compression in your #7 cylinder? Maybe a ring or piston or head gasket has gone bad causing the loss........

I would NOT recommend headers.
Here is a previous link with a similar discussion: viewtopic.php?f=1&t=27050&p=232688&hili ... 90#p232688

BarnieTrk

[Toyz]

BarnieTrk has a good point again, Ron. I would certainly consider a leak-down test prior to dis-assembling. It might be as simple as incorrect valve lash.
Paul

[6166 Junkyard Dog]

HERE'S A problem on a FE Motor in truck I bought, still ran ok but that ticking like a bomb ready to go off, had to pour gas in carb to get started and they where told most likely motor was bad, well now on #1 bent push rod, fixed that still ticking, #5 bent pushrod, still had to put gas in carb to get started, ?, well fixed it and easy, vacuum hose off carb was plugged to PCV and some idiot used vacuum hose to PCV which it has to be thick walled vacuum hose as well or will cause problems and now starts up fine so sometimes it's the simplest that can lead to drive you crazy... One thing is headers is not the answer unless you like replacing starters and they will go out at worst times, Header will have to be loosened to get starter out, Last one I did was in a Motel parking lot at 105 degrees,, we tried all different ones and final results where : headers eat starters way too much heat unless your only going to drive once in awhile

[Limestone66]

Paul i havent even pulled the valve cover off yet. This started week before last after taking a trip down south for a christmas party. Havent really had the time to do some careful troubleshooting to see whats up yet but i will. Barnietrk's observation is sound when comparing headers to cast iron OEM, except for his statement above 3500 RPM. Headers will out flow any OEM exhaust manifolds at any RPM, but i'm not here to 'bench race' with anybody, tho it would be intriguing. I will know more about this after i do my assessments to the old girl, starting off with pulling the damn valve cover off and check to see if any valve keepers popped off. As you can tell, ima still perturbed over the idea of spending more money on this old truck after i've already spent quite a bit of money on getting the heads reworked, but 'Limestone' be a 'labor of love', just like everybody else.

[William-in-St George]

FE's are famous or infamous for bending pushrods. Check that first. New exhaust manifolds are available on ebay for reasonable prices. Personal opinion and I know everyone has one but headders can be a real PITA. Think that one over before you make your move. IMHO.

[Limestone66]

FE's are famous or infamous for bending pushrods. Check that first. New exhaust manifolds are available on ebay for reasonable prices. Personal opinion and I know everyone has one but headders can be a real PITA. Think that one over before you make your move. IMHO.

Yeah they are, and ive already thought it through, gonna stay with cast manifolds but with a new dual exhaust system. Left manifold has a cracked flange as well as numerous cracks or fissures, somebody messed up the last top bolt hole going into the head and redrilled and tapped it out to 7/16th, looks odd but its doing its job. Right manifold shows massive pitting and still more cracks. Gonna look into acquiring another set, maybe off E-Bay or CL. I noticed while lurking around Summit that Dorman makes aftermarket cast iron exhaust manifolds for the fe. Wonder how they are. Just asking. Thanks for the response and OEM Pep talk. You too 'Paul', ima good listener.

[Toyz]

Ron, I will check "inventory" I should have a set of manifolds around here. If I can find some, they're yours. I'm one of those diehards who prefer headers , especially the cast factory items!
Paul

[Limestone66]

Pulled the cover today to see if anything was amiss...........Nothin. Took a few pics of my exhaust manifolds. What yaw think?



Both sides show massive pitting and neglect.



Crack runs adjacent to the power steering box, or right at the #7 and 8 cylinder. No leaks, but ugly and untrustworthy.



Another view from the ground.



Cracked exhaust mount.





Passenger side exhaust. No cracks but a couple of superficial holes. No leaks that i could tell.



Drivers side worst then the other. Gonna replace these here pretty soon.

[Toyz]

The holes on the passenger side appear to be the choke stove well and are probably blind holes. The cracks will undoubtedly expand over time. The crack on the head at the manifold ear is often caused by a too-long capscrew threaded in and contacting the non- threaded area. I have not pulled the ones off the junk 360 here but will save them in case you need them.
Paul

[Limestone66]

As always, yer input on the matter is invaluable 'Paul'. Both valves opening and closing properly when i ran it with the cover off. Pushrods seem good as well. It has a definitive 'clicking' noise in the head, not usual valve train noise because i do know the difference. There are no exhaust leaks to be heard or found, because i have checked everywhere. Number 7 cylinder is not firing and i hafta assume it be a blown gasket, burned valve, faulty valve or valve seat. In any event the head will need to be pulled to see what the problem is, and 'Limestone' is scheduled for repair in the first week in March and will run it like it is until then. I dont think it will get any worse than what it already is, which surprisingly aint too bad. I will find some replacement manifolds before that time and have them ready. Dont want to put anybody out on this.......Not my way. Thanks for the offer.