manifold leak

[hjans]

Hi there
Today, at the end of rebuilding my '59, i tested the manifold on airleakage, although i was sure there could not be one.
And gues what : there was one ! And a major leak !
Tried re-installing the manifold, tried other o-rings, tried again other o-rings,tried a second manifold, but the leakage stays.
I'm now wondering if i can use silicon-seal or silicon-gasket .
Anyone experience with this ?

I have a bad feeling on using the (wide) rubber seals, and new heads are not an option. ( $$ )

Any advice ?

Hans

[Ohio-Rider]

I like the rubber bands combined with the “o-ring to rubber band” conversion adapters sold by James products. The conversion kit takes up the small space left by not using the o-rings and keeps the manifold from beating the hell out of the head spickets.
-Steve

[NightShift]

Dear Hjans,
Are you using clamps with little screws like the originals or 1/4" studs?
Silicone glues dont last at all in USA gas but its probably better everywhere else.

Dear Steve,
How do you get the wide bands in there without taking a head off? Stretch them a whole bunch?

R'spectfully,

[Hog54]

Did you line up the manifold before you tighten down the heads?I always install the manifold first before I tighten the heads down,so I know they line up straight.I install just the clamps,no o-rings just to get everything lined up.

[Ohio-Rider]

Dear Steve,
How do you get the wide bands in there without taking a head off? Stretch them a whole bunch?

R'spectfully,

I first put the bands on the manifold at an angle so that the majority of the band is towards the center of the manifold, then install the manifold from the left side of the bike. When installing the manifold I insert it while holding it at about a 30 degree rotation. With an original manifold the bands will just pop themselves into place as the manifold is rotated back into place. With an S&S manifold they can be a real pain in the butt to install because of the extra length of those manifolds, there is very little wiggle space, but it can be done.
-Steve

[socalrider]

hans
on 6/17/10, i posted a question with the same problem as you. i followed the advice cotton gave me in his response and located a hairline crack on the intake spigot on my front head. thats where my leak was coming from.no way i could have found that without following cottons advice. i wish i knew how to link you directly to the post. the best i can do is suggest doing a search on this site ,type in "manifold leak" and look for the post with my name (socalrider). i think you can also narrow down the location by using the date i posted the question.(6/17/10)
suerte,
arnulfo
los angeles

[FlatHeadSix]

Anulfo,
let's see if this works:
https://www.hydra-glide.net/phpBB3/view ... ifold+leak

mike

[hjans]

Are you using clamps with little screws like the originals or 1/4" studs?
I use the small screws

Did you line up the manifold before you tighten down the heads?I always install the manifold first before I tighten the heads down,so I know they line up straight.I install just the clamps,no o-rings just to get everything lined up.
didn't do that, going to try it asap. Possible without removing the exhaust ?

on 6/17/10, i posted a question with the same problem as you. i followed the advice cotton gave me in his response and located a hairline crack on the intake spigot on my front head. thats where my leak was coming from.no way i could have found that without following cottons advice.
going to check this also, but do not think this is the prob because the leakage spot moves

Silicone glues dont last at all in USA gas but its probably better everywhere else.
There are in fact silicon based liquid gaskets that withstand gasoline ( as they state at least) fi Kent gasket2 ( european product). Guess there will be more...

thanks for the advice/feedback, ......"i'll be back..".
Can take a while for reasons of lack of time.

Hans

[Cotten]

Hans wrote:
>There are in fact silicon based liquid gaskets that withstand gasoline ( as they state at least) fi Kent gasket2 ( european >product). Guess there will be more...

Hans!

There are many excellent sealers, glues, and such produced that truly withstand gasoline, even common shellac.
The problem is that pump fuels are not just gasoline,... and you never know what will be coming out of the next pump, nor next year.

As long as the World is running fuel-injected vehicles, there will be digestive additives and detergents that compromise non-hardening sealers. The probability of illegal dumping into station tanks is yet another threat.
The only way to avoid adding a lit fuse to your assembly is to not apply anything that can be attacked.

In the USA especially, that even extends to common O-rings!
I highly endorse JAMES viton O-rings, as they have survived my testing in local fuels so far.

Air leaks tend to "telegraph" themselves to different spots as the O-rings are compressed, so I suggest testing each head spigot separately with a #9 rubber stopper or something appropriate, for casting porosities or micro-cracks.
(And although this is not the problem you cite, please remember to test the pan cover screw over each intake port to cover all bases for the future.)

I wish you patience and Good Luck!

.....Cotten

[hjans]

found the bugger : see picture.
Guess i have a new challenge

Today some men where working my (propane)-gasline : big leak there.
They used a rubber very thin dual side adhesive tape.
Maybe give that a try, 2 layers over the o-ring.

Hans

[steve_wood]

Hans;

Could you add an arrow to show the spot?

[NightShift]

Dear Steve and Hans,
If I may be of assistance,

hans.jpg (20.48 KiB) Viewed 1447 times

A good TIG man can patch that and file it to shape as good as new.

R'spectfully,

[Hog54]

Yeah,you should of fixed that before you even put it together.

[hjans]

Yeah,you should of fixed that before you even put it together.

Of course you're right, cannot understand why i missed it.

But it shows i'm not the only one missing it

Hans

[hjans]

(And although this is not the problem you cite, please remember to test the pan cover screw over each intake port to cover all bases for the future.)

I wish you patience and Good Luck!

.....Cotten

Cotten, thanks for your opinion.
Can you please explain the above, do not understand what you mean.
Thanks

After lining up the heads i installed the manifold, and the leak is gone ( 15psi)
Think i let it be this way till next tear down reason.
Hans