PAG logo


Headers for small block Moto Guzzi engines

I received a number of e-mails and pictures from Tom Rae and Rob Jenkins who are both in sight of the finish line installing small block Moto Guzzi engines into their cars.

The first one is from Rob Jenkins

Hi David,
Here are a couple of pictures showing my "tempory" solution to the header problem! Standard Guzzi downpipes cut and welded with 1.5" flexi pipe. They work well and have a certain vintage look.. Hoping to upgrade when funds allow.
Rob Jenkins

I received these from Tom Rae.

The current situation is that Rob is preparing his car to get it to Phil for measuring up the exhaust system. Phil prefers that a) a balance pipe is used and b) that it is not up front; so presumably his option will incorporate this. For my part, I prefer, if there is a balance pipe, that it is up front similar to Silverfish. Thanks to David Tocher, I have a source for mandrel bent stainless exhaust pieces OZJ Eninginering and I have also contacted a skilled stainless welder I know with a view to getting a set of headers made. I did not contact him before as I knew he did not have pipe bending facilities.
At this point I am not sure if they will have a balance pipe or not but my preference is for one and upfront - I don't have room for one elsewhere anyway! My plan is that my header will match up with Phils standard 2CV exhaust system. I don't know about multiple copies (or cost as yet) but the component parts are not expensive so cost should be more reasonable than my earlier quotes. I will keep you posted.

The second one from Tom

For reasons I have mentioned before, I am pursuing my own route for the exhaust headers, I have just ordered stainless steel 38mm dia 1.5mm wall bends from OZJ engineering, two 180 degree J bends, (centre line radius 57mm, outside diameter 152mm) and legs of 90/200mm and two 15 degree bends, 180mm overall . These will need to be welded together for each side and then welded onto Guzzi collars which I have cut from an old exhaust. I am going to use a 25mm pipe (that I happen to have available) as the balance pipe. So far the cost of the mandrel bends including vat and postage is £56.34, the welding will probably be paid in beer J
I have now fitted the engine in and it is all bolted up. The clutch flywheel etc was straightforward and all went together well. Currently sorting the wiring. Pinching the idea from Dave Parr, I have made a shelf to carry the Lucas Rita Unit, the Rectifier/regulator and the coil. I have used the standard inlet manifolds turned through 180 degrees and mounted the carbs inboard above the brakes, as Rob has done and they seem happy there. I plan to bring the rocker breather tubes to a one way valve and then plumb them into the inlet manifolds but I have not done that yet.
bs, fuel lines, exhausts, and sundry wiring, looking good though.
I will post pics at a later stage.

The last one from Tom

They have arrived! The tight radius will be ideal for my purpose, they are just as they arrived, they will be cut to length welded together then welded to the Guzzi collars and a 1" balance pipe fitted. These were from OZJ engineering as found by David T.

I asked Tom about the fit of the shallow bend.

David, I can photo the stages and measure the end result which is what matters. I am getting it welded tomorrow so will keep you posted. For the 15 degree bend, it will be fitted to the j bend so there is a little bit of flexibility at that join however to my eye they look as near as I require.

Valid XHTML 1.0 Transitional Valid CSS!