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intake manifold clamps

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Mick Inniss

intake manifold clamps

#1

Post by Mick Inniss » Mon Oct 31, 2005 9:27 pm

O.K. guys I have heard Horror stories on different styles of intake clamps on stock Panheads. I'm putting out a pole to Panhead riders on what type of clamps you use and why? I bought a set from a local H.D. Dealership and I think they were imported to Taiwan before they imported them here!!!! What Junk!! :?



Cotten
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#2

Post by Cotten » Tue Nov 01, 2005 3:08 am

I will only use OEM-design clamps with no goobers or bandaids.

Why is because that system works best.

Just pressure test while installing, so you can avoid overtightening and be certain of finding the 'sweet spot' where everything lines up for a proper seal.

mick inniss

intake manifold clamps

#3

Post by mick inniss » Tue Nov 01, 2005 6:48 pm

O.K. Cotton will do it one more time. Maybe the Motor Co don't make them like they use to!! They sure look cheeezie to me!!! Is there a place I can get NOS clamps? Maybe they will be better quality!!! Thanks again Mick Inniss :wink:

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#4

Post by thsmith » Tue Nov 01, 2005 7:10 pm

Mick,

I use stock oring clamps. I got mine from NOSPARTS, part number 27063-57 $14. They seem to work well for me. The previous clamps were aircraft style that were tightened down so tight the oring had slipped out of the groove, previous owner adjustment not mine.

Tracy

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#5

Post by fourthgear » Wed Nov 02, 2005 8:10 pm

I use the modern type aircraft clamps even on Shovel heads, as long as you tighten them properly they seal just fine . The only bad thing is on Panheads you can't take them off or on with out taking the manifold off , they are too beefy, the stock one are very flimsy and can be worked in between the heads and manifold, but they do work.

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RE: Intake Clamps

#6

Post by ozwick86 » Mon Nov 07, 2005 3:42 am

I just put new OEM clamps on my 59 pan and performed the pressure test. All is OK. But, just like the old clamps, after 1 ride both clamps slide back toward each other from the vibration of the motor almost exposing the o-ring.

Does anyone else here have this problem and if so, how do you correct it?

I thought about putting friction tape on each side of the manifold or a dab of silicon to hold each clamp.

Anyone have any ideas?

Thanks,

ozwick

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#7

Post by Cotten » Mon Nov 07, 2005 1:23 pm

Goobers and bandaids add to the problem, and make it really hard to clean up after gasoline melts them.

It sounds like the o-rings are too fat. Have they already swollen from fuel?

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RE: Intake Clamps

#8

Post by ozwick86 » Tue Nov 08, 2005 4:06 am

Cotten,

To your reply; "
It sounds like the o-rings are too fat. Have they already swollen from fuel?

Not sure? How long does it take for the o-ring to swell from fuel?

The new clamps are sliding like the old ones I replaced.

Any other suggestions? I thought I could just put a dab of silicone to hold the clamp in place not to seal.???

Thanks,

ozwick

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#9

Post by Cotten » Tue Nov 08, 2005 1:17 pm

Illinois P4gas will swell Buna-n in a few hours, but it is not ordinarily a problem. Compare them to fresh ones, or measure them and see if a gentle heat lamp shrinks them significantly.

Take a caliper and measure the diameter of the spigots upon the heads, and then compare that to the manifold. If the manifold is smaller, that's a likely culprit.

I cannot condone the use of silicone anywhere except exhaust pipes.

Beware of over-tightening the clamps, or they will distort. Remember, they do not hold the carb onto the machine.

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#10

Post by thsmith » Tue Nov 08, 2005 6:06 pm

Not sure if your intake was converted to o-ring from plumber but if it was most times the new oring intake will not fit between the nipples. Most times people will machine down the outer edge of the intake reducing the oring space, you have to also machine down the inner lip the same amount of the ouuter lip.

When I bought my 49 the heads had been converted and could not keep the rear oring from moving out of the space. I measured a stock intake lip and turned my down until they were back in spec, 50 thousanths I think.

Tracy

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#11

Post by fourthgear » Tue Nov 08, 2005 7:58 pm

ozwick
Is there any stress on your carb. support ? in other words is it pulling the carb. & manifold away from the normal posistion . There my be some truth that the stock clamps are not for support, but they do support it ,other wise it would just pop off. If your manifold is up to spec's ,Try the aircraft type clamps and you will see that they will support the carb./manifold assem. and when adj. properly you will get a good seal and support from vibration and undo stress from missadj. support brackets. They get a bad rap mostly because of missuse . I have seen stock set up pop off with just slight back firing through the carb. My two! Note : I just had conversion nipples welded onto my heads because of bad threads in the heads and after puting the heads back on and pressure testing I had leaks around the new welded nipples ( they were welded on the inside only but , my O- ring type system with aircraft type clamps did not leak at all. They tested the heads under vacuum in a flow beanch and said it held a vacuum and it was ok, this is a shop that does alot of HD heads , when they asked how I knew they were leaking , of course I explaned to them how to test them and they had never heard of testing them that way ( I can see Cotten cringing on that statement.)We all know these old castings can leak right though the casting and there welding looked real good , just not good enough. Long winded , yes ,sorry.

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#12

Post by mbskeam » Wed Nov 09, 2005 5:37 am

hello,
yes check the manifold groove and head.

fourthgear.......

wow....this is the time to find a diff welder.
if you find a rubber stoper that fits the intake port in the head, with the valve in place, you can test before bolting on heads,..... like right at the weld shop

I use the aircraft style and have had good luck with these, I did try the 1/2 metal clamps that are bolted together. and these did not do that well as they cut the o-rings in half, this was less than 1000 miles..... see pics
man was it hard to start.........LOL

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#13

Post by fourthgear » Wed Nov 09, 2005 1:22 pm

Man thats some dramatic photo's mbkseam, I took the heads back yesterday with an altered sink drain plug, (1/4 barbed fitting )He has done a lot of older harley heads and I showed him my manifold adaptor and he kept the altered plug for testing . Kinda makes ya wonder how many heads were done with out proper testing and how many lean running heads are running around out there. How many more uniformed repair shops are out there . These web sights are above the curve and I for one can't thank them enough for this and the other sight to exchange info. Thanks.

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RE: Aircraft clamps

#14

Post by ozwick86 » Thu Nov 10, 2005 4:44 am

I did not check the diameter of the manifold with calipers. I do have a carb support bracket. Can someone give me the address of the website that has the aircraft style clamps. I think I will try these.

One installation question. I had to bend open the clamps I have now and dive them in at a angle to get them to fit between the manifold and the head with the carb off. Do I have to remove the carburetor to install the clamps and or will I have to bend open the clamp and dive it in around the manifold and the head with these aircraft style?

Thanks,

ozwick

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#15

Post by fourthgear » Thu Nov 10, 2005 1:25 pm

ozwick
The aircraft clamps can be somewhat of a hassel to put on . I take the carb and manifold off and roll the O-rings on the head nipples , put clamps on manifold loose , you will have to wiggle the manifold and clamps into possition , then roll O-rings onto the manifold and they will hold manifold in possition untill you work the rest of the O-rings all the way on , then just tighten clamps a little at a time ( evenly ) you will feel them getting snug , just make sure the O-rings don't pop out of possition when tightening clamps . Once you have the O-rings in the groove , with clamps loose you can see them in possition. JUST DON"T OVER TIGHTEN THEM. Leak check and tighten if needed. (I put carb and bracket on with a couple of bolts to make sure it is lined up right and then tighten clamps then remove carb. to leak check)
They can be seen in JP Cycle , Jireh cycle supply ,or your local dealers, They do make a split version of them some where , I saw a set at a shop yesterday. I use the solid band type. Beware , check mbskeams photo's , I have never used those type.

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