Hose Clamps

Kalun D · 08-02-05, 10:24 PM

As promised in the electric water pump thread this is a post about hose clamps.

All hose clamps are not created equal.

This research was brought on by a custom 240Z Scarab (Chev V8). It had an oversize radiator and custom hoses and tubing from engine to radiator. Hose clamps were just your typical off the shelf piece from the local budget auto parts store. While cruising through the mall the lower radiator hose blew off and dumped all the coolant on the ground. Luckily it didn't happen in a high speed turn on the freeway because it slimed the rear tires. More embarrassing than anything, and the fix was to put double clamps on all the large hoses, which worked in that situation.

The GT40 is a little more crowded especially where the main coolant pipes come out of the tunnel by the front crank pulley. There's no room for double clamps. Hence a search for a better clamp.

These are all 5/16" nut size stainless steel clamps, and all are similar quality of construction.(except E which is 7/16")

Clamp A is an off the shelf typical auto parts clamp. Actually it's their higher line clamp. It's 1/2 wide and the screw holder is one piece and is crimped around the clamp/screw. It's torque rating is about 30 in/lbs.

Clamp B is also 1/2" wide but the screw holder is two piece fastened with bent over tabs. Torque 40 in/lbs

Clamp C is 9/16" wide with a similar 2 piece bent tab construction. Torque 50 in/lbs. This clamp also has a longer length band on the ID that keeps the slots from digging into the hose.

Clamp D is 5/8" wide with a 2 piece swaged tab construction. Also note the longer length bolt for more thread engagement. Torque 80 in/lbs.

Clamp E is 3/4" wide with a bolt and nyloc nut. While it's also 80 in/lbs it probably is more re-usable and vibration proof.

There is another stronger bolt/nut clamp offered at 110 in/lbs. At this torque you may be approaching collapse of thin wall tubing.

Clamp D was used on the GT40, it's plenty strong and has more clearance than the bolt/nut variety. It's called a vibration resistant (high torque) hose clamp. All clamps were torqued with a 1/4" drive in/lbs. torque wrench.

Clamps B, C, D, and E are from www.mcmaster.com (although probably available elsewhere) They are a wealth of information with many specs on most stuff they sell including metal alloys and complete fastener and fastener material specs and applications.

So we've gone from the 30 in/lbs. to the 80 in/lbs. clamp. This may be particularly relevant with some of the kits having large coolant pipe connections inside the cabin. A blown off hose in that position could be disastrous.

Kalun D · 08-02-05, 10:25 PM

photo

Kalun D · 08-02-05, 10:27 PM

photo 3

GraemeS · 08-03-05, 05:00 AM

Hi, I have had the same problem, i found its not so much the clamp but the pipe, have the pipes that run to the radiator had a rib put into the pipe so there is a bump on the outside, i found a smooth pipe with no ridge allows the pipe to slide off, when things get hot and pressure builds up.

Regards
GraemeS

Kalun D · 08-03-05, 12:48 PM

The Z car blew off at the water pump inlet which had a bead on it.

The GT has beads on all pipe ends. Had to make 2 dies for the beader to accomplish this.

Peter D · 08-04-05, 07:55 PM

Very nice piece of research Kalun - thanks !

FWIW, I just got the local exhaust shop to put a slight flair (about 1/8") on the last 1/4" of the ends of the large pipes with their hydraulic flairing machine. This seems to have worked ok so far, but I also put 2 clamps on each joint, just to be sure.

The Type E clamps look to be by far the best - the challenge will be to find a distributor here in Oz so that I can replace my existing Type B clamps.

Do you have a brand name or manufacturer for the Type E's ?

Kind Regards,

Peter D.

Bill Bayard · 08-04-05, 10:12 PM

Peter,

The "Type E" clamps are called T-bolt clamps, and should be available at any good marine supplies dealer.

Bill

Peter D · 08-05-05, 04:16 AM

Bill - damn-it ! That must mean that we don't have such a thing as a "good marine supplies dealer" here in Sydney !!

All I could get was s/s versions of the Type B clamps. [img]/ubbthreads/images/graemlins/frown.gif[/img]

Perhaps this goes some way to explaining why one of our America's Cup yachts broke in half & sank a few years ago - wrong hose clamps holding the front to the back !! [img]/ubbthreads/images/graemlins/grin.gif[/img]

Kind Regards,

Peter D.

Bill Bayard · 08-05-05, 05:48 AM

Peter,

Try a shop that deals specifically with marine diesels. They are sure to have T-bolts on hand or know where to find them locally. Your yachting mate should be able to steer you in the right direction. T-bolts are practically impervious to vibration(never say never), so they'd be perfect for a limited access situation, like a water pump or coolant tube hose. I've had one T-bolt break on me in 20 years of using them, but have never had one vibrate loose. They aren't exactly cheap, but for peace of mind, they're well worth the extra $$$.

Bill

Ricky · 08-05-05, 11:22 PM

Peter,
Any good ENZED, TYCO or hydraulic fitting business here in OZ will have the T bolt type clamps. They are substantially higher in price but very reassuring. Hope this helps,

Regards,
RV

Peter D · 08-07-05, 07:43 AM

Thanks Rick, I'll give them a go, or some marine diesel outfit as Bill suggests..

Kind Regards,

Peter D.

Pete. · 08-14-05, 08:41 PM

[ QUOTE ]

This seems to have worked ok so far, but I also put 2 clamps on each joint, just to be sure.

[/ QUOTE ]Hey Peter, isn't this why Irishmen wear two condoms.To be sure, to be sure? [img]/ubbthreads/images/graemlins/grin.gif[/img]

**brianstewart** · 08-15-05, 03:57 AM

I thought it was Welshmen who wore two - just in case one had a leek in it....

Bill Musarra · 08-15-05, 06:07 AM

If you are still looking for the T clamps, Racer Parts Wholesale has them in their catalogue on page 61 for $11.34 U. S. At least it looks like it.

Bill

Peter D · 08-15-05, 09:07 AM

Now Pete, you would not be having a go at my Irish ancestry by any chance - would you ?? The fact that I have 5 children has nothing to do with the fact that I have little faith in rubber !

Brian, the Welsh indeed use two - have you seen the size of the damn leeks they grow over there, &/or, have ever heard complaints from a Welsh girl ?

Bill, - back to normal now ! Thanks for the tip - if I can't find them here in Oz, Ill give RPW a try.

Kind Regards,

Peter D.

Craig White · 08-15-05, 05:23 PM

Peter D, I've seen those bolt/nut hose clamps at many a swap meet 2nd hand, so they must be available here. Let us know how you go. [img]/ubbthreads/images/graemlins/smile.gif[/img]

Pete. · 08-15-05, 08:19 PM

Peter D, Definitely not having a go at your Irish heritage.
My Ancestors come from Derry and I am the eldest of six. [img]/ubbthreads/images/graemlins/wink.gif[/img]

Ian Anderson · 08-18-05, 06:59 AM

A Source of these clamps
http://www.holdtiteuk.co.uk/about.asp

And a site with a load more information
www.jupiter-clamps.com

I have nothing to do with either establishment

Ian