One reason I dont like the 300:

EXHAUST MANIFOLD ALWYAS LEAKING,
sometimes it leaks at the Cyl head, other at the mating surface with the intake manifold.
I changed gaskets 6 times a year maybe more.
Anyone got a trick to eliminate this leak, saves me extra cost of swpping into V8-352.
I appreciate all your ideas.

66 Ford F100
I-6, 300
1984 Carter 1brl carb with elect choke
380KM with full tank (69 Lites)
Hamid.

 

did you get them plained so everything is straight again? thats what i have to do with mine sometime soon

 

6 times a year?? Wow, I've never had that much of a problem. When you take it off to switch out the gaskets, have you ever had your manifolds planed? If not, they could be warped and every time you put them back on, they're just going to pull on your bolts until they leak again.

 

get your manifolds machined to fit properly together then you will not have anymore problems, heat distorts manifolds

 

Never had a manifold leak in 30 years and 400,000 miles of driving 300s (three of them). Something else must be wrong that is causing this.

 

You might try using doubled gaskets, that's what I did and it solved my leak problems. Just for a little added insurance, I use a thin layer of silicone to glue the gaskets together and on the mating sufaces. I like to use Permatex Ultra Copper silicone on mine, it holds up to the heat very well. I know what you're going through I fought that problem on my 84 F150 with the 300... this did the trick. No offense but that is not a very good reason to get rid of your 300.

 

You could just say screw it and let it leak to save the hassel, I would have by now

 

Hi all:
I do love my 300, I just got from a 1320 Miles trip with that leak. It fades out with the speed increases. I just dont like anything not wright with the engine.
I appreciate your respond.

justin_jkj:
I done that once, but I had to put hand cut gasket one time which changes the spaces and caused the non straight surface, I liked that idea, Thanks.

AbandonedBronco:
ya, 6 times ( once you remove the manifold the gasket now is week and it gets torn or cut, thats it, put a new one. Thank you for your answer.

werneil:
Thats what I am planning to do, my manifold gets craked some times and they are hard to weld due to the type of material. Thanks for your reply.

TallPaul:
the reason now is clear as the members replied ( manifolds are not straight) and I sow that on one side by my eyes. Thank you for your hint.


Pkupman82:
Your idea is kinda briliant, but I have to plane the manifold first, one thing I doubt if I can get down here in Saudia Arabia which is the ( Permatex Ultra Copper silicone), I will look for an alternative though. Thanks for your help.

scrapyardking:
too lazy ha, sound you're saying: I am going to take the manifold out for repair anyhow, so let it leak the heck out. thanks for your funny words.

 

Major kudos for rocking a Ford pickup in Saudi Arabia!

The cast iron manifolds do warp with age. I'd say the best fix is to get a set of EFI manifolds off eBay (Walker Y-pipe or a custom made one), or a set of headers from your favorite performance catalog. Flow better, better power & response, and they don't warp & leak like the stock log manifold does.

How's the parts availability in Saudi Arabia? I'm thinking you can't just order whatever you want from Summit Racing or whatever (due to shipping, probably).

 

EFI manifolds would be nice.

I had a 460 with a leaking manifold. Had snapped a bolt when it warped. Mech put a gasket to take up the warp (didn't know his machine shop would resurface it) as this iron manifold normally didn't have a gasket. Then the mech put antiseize and the bolts kept backing off. I was tightening it all the time.

 

BigBlue88:
Thanks for replying, I will do anything to get rid of that leak, EFI manifold sounds good, but I need sometime to search since this is new to me.
300 engine parts are rare down hear, 352 are much popular engine and most of the parts are available.
I dont have any problem with shipping except the high cost, I had a a credit card problem with summit racing, once, but there are a lot of altrenative beside them, although they are the only one that carries custon fan blades for that eng.

 

BigBlue88:

But you did not mentioned what year model EFI manifold will fit to my 300 engine head, my engine block P/N: C6TZ-6010-A, and was taht srtaight bolt on.

 

Hamid-
Any year EFI manifolds from any 300-six vehicle will fit, even vans. Model years 1987 through 1996 are EFI vehicles. I got my manifold set on eBay, used from a scrapper for $65. You may have to cut one or two of the mounting ears off the EFI manifolds, and you'll have to weld closed the EGR fitting on the rear manifold, but it's bolt-on. I've got pictures in my gallery of retrofitting the EFI manifolds onto my '76, which should be identical to your '66. There's lots of threads about the EFI manifolds, and the consensus is they're almost as good as long-tube headers for power and economy, and flow almost as well too, and never leak, unlike headers, which are easy to install incorrectly. Commonly reported effects of installing EFI manifolds are increased throttle response and much better power on the highway, especially at engine speeds around or beyond 2500RPM.

There were only minor modifications to the engine through the years, and essentially everything is interchangeable- heads, ignition systems, exhausts. Popular combinations are putting carburetor heads on EFI vechicles for a slight increase in compression, and using carburetor timing gears on EFI vehicles to get back the 4 degrees of cam timing Ford took away for the emissions systems. For your truck, acquiring the Duraspark II system from (approximately) a 1976 to 1986 truck will give a much, much better ignition system than your points system. The distributor and coil are a drop-in replacement, I believe, and the wiring in simple.

There's lots and lots of great information on this site. We'll be able to help you out with anything you need.

 

BigBlue88:
Now it is an interesting subject since those EFI exhaust manifolds will work a alot better than the traditional ones, I need you to reply on the following questions:

1- Are the 87-96 EFI exhaust manifold of the daul outlet pipes?.
2- What about the old intake, will it go with the new EFI exhaust or do I have to put another intake, and if yes would the same years model 87-96 fit?.
3- During my search on the EFI intake I noticed that there is an upper and lower manifolds, can you explain more on that?.
4- Is the old gasket can be used ( I mean the one for the old exhaust and intake manifolds)?.

You have been a great help, thanks B.B.88
Hamid.

 

Find leak, put Permatex into the void. It works! Prior to that I've replaced gaskets many times. Permatex has lasted two years so far.