Cam 6618 Inlet Manifold Water Stubs - Replaceable?
#1
Posted 01 January 2021 - 07:44 PM
Couple of questions though. The water inlet and outlet are badly corroded and pretty much un-usable. I know that many advise not connecting anyway, but I like fixing things, so out of interest has anyone very replaced the steel inlet and outlet?
Could they be drilled out and new fixed in some how? Has anyone ever repaired anything similar?
Thanks
#2
Posted 01 January 2021 - 08:06 PM
There are a couple of ideas in this thread
https://www.theminif...inlet-manifold/
I haven't had to repair one yet, but I have looked at them as I know sooner or later, one will land on my bench, needing these to be replaced.
Drilling them on size is tempting, but is a risk. The steel pipe would be harder than the alloy of the manifold, so if your drill wandered off, it may grab in to the alloy. You could try drilling just undersize, reducing the steel tube to having a very thin wall, then patiently 'cave it in' then grease up a new tube, perhaps in stainless, and press that in. While it would take some time, you might be safer working with an adjustable reamer and gradually cut the steel tube away from the inside.
Another idea I have had is to cut the steel tubes flush at the manifold, then drill & tap for some threaded brass adaptors. It may give a reduction in ID sizes inside the adaptors, but I can't see them reducing flow by much.
#3
Posted 01 January 2021 - 09:08 PM
I wonder if these are similarly interference fit that could be heated (alu heated not the pipe) similar to that thread.
#4
Posted 01 January 2021 - 09:20 PM
Since the water heating is unnecessary, one method of repair would be to get a length of steel tube of the correct outside diameter, cut the old corroded stubs off flush, then drill through both sides and slide the tube in place so that it goes all the way through with protrusion each side the same as the old stubs. Use some Loctite or other structural adhesive to, maybe 'JB Weld' to secure & seal the tube and prevent air leakage.
The water hoses could then go on both sides of the protrubing steel tube and it will look pretty original.
#5
Posted 01 January 2021 - 09:34 PM
I just turned up a couple of new pipes in alloy, chiseled what was left of the steel ones out and TIG welded them back in.
A blob of chemical metal would have secured them without issue as they were an interference fit.
#6
Posted 01 January 2021 - 10:35 PM
#7
Posted 01 January 2021 - 10:48 PM
If you have a look at the "classic mini spi" group on facebook there is a guy called Roger carpenter that does refurbishment kits for spi heated manifolds that includes those pipes. Not sure if they are exactly the same, but he might be able to make some the right length for you. They are just pressed in so a good vice gripping the old pipe and you should be able to pull them out.
Roger posts on here as Pops_Guild
#8
Posted 01 January 2021 - 11:41 PM
I'm reasonably sure these have one length of steel pipe right the way through and they are cast in place.
#9
Posted 02 January 2021 - 09:47 AM
You refer to post 23 of my engine and gearbox rebuild thread (https://www.theminif...earboxes/page-2) to see how I replaced the pipes. In the meantime I have pressure tested the repaired manifolds and fo u nd no leaks.
#10
Posted 02 January 2021 - 10:27 AM
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