A Guide To Help Refurb Spi Inlet Manifolds

Hello,

 

I've posted on here (and on Facebook) before about my experiences with refurbing NLA SPI Inlet Manifolds and I decided to put together a guide as I've had a fair number of questions about it all. I'm sure its not definitive and I'm sure there are other ways, I'm not claiming to be an expert, just a guy who wanted his inlet manifold to be better :)

 

Thought I'd share, hope it helps some folks.

 

Updated 5th Nov 19 - Made a few revisions/tweaks, v2.1.

 

Updated 24th Oct 20 - Made a few more revisions, v2.2

 

Update 23rd Feb 22 - I made few videos on that YouTube thing, showing how I do a complete refurb (using a kit).

 

Part 1 - Classic SPi Mini Inlet Manifold refurbishment, removing the pipes and core plugs. - YouTube

 

Part 2 - Classic SPi Mini Inlet Manifold refurbishment, putting the new pipes and core plugs back in - YouTube

Edited by Pops_Guild, 23 February 2022 - 05:07 PM.

Excellent!

Many thanks for taking the time, this is sure to help many fellow TMFers.

Pinned

FS

Edited by FlyingScot, 10 September 2019 - 05:09 PM.

Lovely work !

 

I'm sure that will help out many others. Very kind of you to do the write up and share here.

 

 

Just on bending the pipes, only the other day I had a similar joggle I had to do for a custom heater set up in a short length of pipe. I have done these with benders, but with the bends so close together, it's not easy to keep them 'flat' in the other plane (if that makes sense). I toyed with the idea of machining up a press tool for doing these, both at the same time in the press. The idea being, lay a cut section of pipe in a lower die, fit the upper die, press and (hopefully!) a perfect and repeatable pipe section comes out. I've not made these types of dies before, however, I have done others for folding sheet metal with great success. As the volumes are very low, I've only done these in ordinary mild steel and grease them before each use, also making sure the steel is clean before pressing. Some of these soft tool are over 10 years old and done probably over 100 pressings, still going fine. I have also had these plated, which has increased their wear resistance and also stops them rusting.

You're welcome. Nice to give a bit back!

 

The pipes are tricky and I too have thought about creating a press tool for the job, start with a casting to create the rough dies and go from there. I just don't have the time at the moment to tinker that far, maybe one day.  As you say mild steel or brass will likely play along with that process, not sure about stainless steel, the press would need to be super tough. 

 

To be honest mild steel pipes with some plating would see most mini's through on the inlet manifolds. 

 

Nice to hear about what others do to keep their motors going too, thanks for sharing :)

Brilliant stuff. Thank you.

Thats great, thanks. On the subject of pipe material would copper work?

Thats great, thanks. On the subject of pipe material would copper work?

 

No problem.

 

Yes any pipe material will work but what is critical is the OD of the pipe. Copper would be great because it's much easier to bend but I have not yet found a supplier for the correct OD tolerance needed for the interference fit. I think it's all made in plumbers pipe dimensions. You can find brass of around the correct OD and that's easier to bend but its pricey and without the right sized benders its more prone to pipe flattening. Brass is a different kind of awkward to the Stainless. 

Cool, thanks. I thought that may be your answer. I am going to need to do this job at some point in the future.

Gute Arbeit! Good job thank you for your efforts done in this matter.

Awsome document! Thanks a lot! 

 

CAn you help me where to find the plugs?

 

Thank you for your time and effort

 

Gabor

Thanks for sending me the link to this, Roger.

I posted this info as an update on the pinned post but in case folks read from the bottom up...

 

Update 23rd Feb 22 - I made few videos on that YouTube thing, showing how I do a complete refurb (using a kit I make, saves folks the faff of bending the pipes etc.).

 

Part 1 - Classic SPi Mini Inlet Manifold refurbishment, removing the pipes and core plugs. - YouTube

 

Part 2 - Classic SPi Mini Inlet Manifold refurbishment, putting the new pipes and core plugs back in - YouTube

 

Have fun...and a few more pics to whet your appetite :)

 

Great stuff, thanks for posting.  

What is better? Cooper or stainless pipes?
 

I guess cooper would be easier to manufacture 

Stainless would last longer albeit more expensive...