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woodsy
woodsy

Posted: Tue Sep 27, 2011 9:21pm

Post Subject: BMC 1.5 Calorifier connection

I have been trying to find a supplier for a hose tail to connect the rear port of the cylinder head on my BMC 1.5 diesel to my calorifier, the thread of the take off appears to be a 5/8 - 16 tpi do you know of anywhere that can supply such a connector? TIA Kevin

Tony-B
Tony-B

Posted: Wed Sep 28, 2011 9:36am

Post Subject: BMC 1.5 Calorifier connection

Well, we made our own from the plug, some copper pipe and silver soldering when I was on the hire fleet. ASAP Supplies list item 206799 as an Adaptor for Cyl Head 5/8 UNF 1/2" hose and I am sure Calcutt Boats or AMC Thornycroft could also help. I would also expect the larger chandlers to stock something suitable. You may want to look at ASAP item 206712 that is a elbow hose with a 1/2" T. This may need trimming to size but would make fitting the calorifier return easier that cutting hoses and making up a copper T. Tony Brooks

woodsy
woodsy

Posted: Wed Sep 28, 2011 10:53am

Post Subject: BMC 1.5 Calorifier connection

Thanks for the reply, I had started to make my own and had the plug drilled and tapped to 1/8 bspp but I am not sure the flow would be enough, so thought I woul try and get a purpose built item, the one from asap supplies is a 5/8 unf 14 tpi and will not fit that port it will only fit the hole for the temperature sender, I will try Calcutt & Thorneycroft as suggested, Thank You, Kevin.

Tony-B
Tony-B

Posted: Wed Sep 28, 2011 2:20pm

Post Subject: BMC 1.5 Calorifier connection

FWIW we used to drill a hole right through the plug that was as large as we felt comfortable with - (say 3/8) and then bore a recess into the the hexagon part of the fitting to accept a short length of engineer's copper pipe which was then silver soldered into the plug. You could try MGB websites because I think some BMC cars used a short stub pipe that screwed into the hole. TB

woodsy
woodsy

Posted: Fri Sep 30, 2011 4:31pm

Post Subject: BMC 1.5 Calorifier connection

Hi Tony, Just a note to let you know that Thornycroft supplied a part they said would fit but it turned out to be a 14 TPI as well, so its back to the drawing board. Regards, Kevin.

Tony-B
Tony-B

Posted: Fri Sep 30, 2011 7:43pm

Post Subject: BMC 1.5 Calorifier connection

I was almost sure that you had the tpi wrong but as I do not have one to check I could not say so. The only thread I could find any 5/8" 16tpi was single reference to a BMC special related to Mini engines and that one used a whitworth profile. TB

woodsy
woodsy

Posted: Fri Sep 30, 2011 8:38pm

Post Subject: BMC 1.5 Calorifier connection

Hi Tony, You are Correct I had confused the Thread on the supplied hosetail it is in fact 18 tpi not 14 as I said but the plug out of the engine is 16 tpi, the unf thread only goes into the engine two turns and stops dead. with my vernier set at 0.25 it covers 5 threads exactly not counting the fist thread that is 4 x 4 = 16 threads or have I got it wrong ? the unf is 4.5 threads per 1/4 inch.

woodsy
woodsy

Posted: Fri Sep 30, 2011 9:20pm

Post Subject: BMC 1.5 Calorifier connection

These people from another forum seem to be having a similar problem to me. http://www.canalworld.net/forums/inde x.php?showtopic=16069&st=0

Tony-B
Tony-B

Posted: Sat Oct 01, 2011 10:10am

Post Subject: BMC 1.5 Calorifier connection

Personally I would never try to measure the TPI in that way. I would use a thread gauge to ensure I did not miss count the threads. I am unclear as to why you have subtracted the first thread because you then multiply the figure by four. I suspect you may need to add 3 to the 16TPI, but as I said I would use a gauge. If the worst comes to the worst you should have enough metal around the hole to tap it to a known thread - possibly 3/8BSP. Tony Brooks

woodsy
woodsy

Posted: Sat Oct 01, 2011 12:03pm

Post Subject: BMC 1.5 Calorifier connection

Thanks for your help, I will see if a local engineering works can help. The thread measuring procedure I followed is detailed below. Regards, Kevin. The thread pitch can be measured with a steel rule, as illustrated in Figure 44, or a caliper or comparator can be used. The thread pitch is the axial distance from one thread groove to the next. By laying a steel rule down the axis of a screw and counting the number of thread crests in a given length, the pitch can be determined by dividing the count into the length. In the example shown (Figure 44), there are 5 pitches in 1 in. so the thread pitch is .200 in. Note that the number of threads per inch is the reciprocal of the thread pitch. A common mistake is to count the number of threads starting with "one". This will lead to a one pitch error. Make sure you start with "zero" for the first thread. To double check your pitch determination, check your pitch determined by count against your actual pitch measurement. FIGURE 44

woodsy
woodsy

Posted: Sat Oct 01, 2011 7:51pm

Post Subject: BMC 1.5 Calorifier connection

Calcutt boats make their own to fit that port I have ordered one from them, thanks again. Reply From Calcut: You are quite right The "B" series did use the obscure 5/8" thread,We hand turn a spiggott with a 1/2" OD part no 12A 2075 @ £11.76 we are currently OOS but could do a good used unit at the same price plus £2.50 P & P

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