Martini RSR engine build

[Mike_Moore]

Thanks for all the kind comments guys, and yes Tom the small measurements seem to mean so much at this level in the set up and final performance.

One of the common problems people have putting high horse power on the 6 bolt crank is the flywheels coming loose, it's the vibration and harmonics from a badly set up engine that does it, the wrong measurements in the above set up, or in the head volume matching that I will describe next can all contribute to a possible failure.

[Mike_Moore]

Now the valves are in, we can now properly cc the heads for the next stage which is to make sure they all have the same volume. This is done by placing a flat clear plate with a central hole as a filler and another at the top to let out the air, and then filling with fluid, in this case paraffin. This is a very controlled process to get right, with bubbles being a big problem.



Having then measured the volume in each head and seeing the discrepancies, you have to machine out small amounts of material from each spark plug pocket then clean it all out and set up the measuring system again. It still won't be right unless you are really lucky so you take out the fluid, clean it up, machine again, clean that up fill with fluid and measure again hoping it's right this time.



Then just the other 5 heads to do. You begin to realise how time consuming this all is and why a competition engine takes so many hours to build. We got the volumes to match in all heads to within .2 of a cc in the end which is pretty good I'm told. Note below the valves are numbered to the particular head, which is seen prior to cleaning.



Another test before fitting the heads permanently, is the head to piston clearance and valve to piston clearance, again we had the computer predictions but have to confirm it physically. You have to fit up the cam and rocker and do the cam timing to bring the piston to tdc then use bits of plasticine, fit the head then torque it down. For the valve to piston clearance you set up a micrometer and measure the valve stem travel to work out the gap.



Plenty of gap for safety and as the pistons have deep pockets more than enough for even the occasional over rev!


As I mentioned before the computer prediction for the compression ratio was 10.1:1 slightly lower than we hoped for, but it's not until you can physically test the head in situ that you come up with the true figure. The bench volume test as outlined earlier gave us a new better figure but to make sure we did two more tests. First using the twin plug head already torqued down we fitted in place of a spark plug a specially made one with a hollow centre to flow paraffin through, then measuring the fluid put in and rocking the engine to get out bubbles we got a new figure of 10.4:1. I was really pleased but it still wasn't accurate enough for Neil, the problem being you can't see in and therefore can't be sure you have all the bubbles out! He had a final test up his sleeve. He took off the twin plug head and fitted up a scrap head with a known volume which had a drilled hole dead centre through the top into it's chamber. Now pouring in the fluid, as it's a central hole gravity ensures the air rises to the top and out, giving now the most accurate figure you can get, and doing the calculations by hand it confirmed the 10.4:1



So now the heads were done and ready to go on.

[andrea70]

Mike, words are unnecessary....

Andrea

[Mike_Moore]

thanks Andrea!

Final set I promise! (for now)
Just another gratuitous view as the heads finally go on for the last time.



Neil torque's them down.



Racing oil tubes go on as the cam towers are fitted for good.



The fibreglass shroud is fitted up and then the high butterfly goes on with the correct style barrel nuts.



Neil puts the finishing touches to the build for the time being. Waiting on the oil fed cams to be finished and the solid rockers are still causing a few problems but hopefully will be sorted out soon.



All for the time being............

[jameshtaylor]

Do you have any more information on the black finish? Looks superb.

[Flunder]

Mike:

Great thread!

Would you please describe the steps to modify the scavenge pipe and strainer to fit the high flow GT3 oil pump so as to keep a flat early sump plate, like an original RSR (and ST).

Thanks,

Tom

[mike curnow]

I have never seen those oil return tubes with the screen? Do you have a part number? Or a source. Is the paint something special or just black paint?

[Mike_Moore]

Mike:
Great thread!
Would you please describe the steps to modify the scavenge pipe and strainer to fit the high flow GT3 oil pump so as to keep a flat early sump plate, like an original RSR (and ST).
Thanks,
Tom

Hi Tom, sorry not responding earlier. The scavenge pipe modification is basically to cut off the dome strainer then weld a new section of the wide diameter pipe on to lengthen the pipe.
You then cut to chamfer the end to fit through the enlarged hole of an early strainer dish. Hope that helps.

I have never seen those oil return tubes with the screen? Do you have a part number? Or a source.

Mike, the oil return tubes are custom made by Neil Bainbridge for his racing engines. His secret which he is happy to share is to use the fine wire stainless mesh from an SC air filter and cut to shape and fix into the tubes using a circlip to hold in place, be warned they are a devil to fit though! The idea being that God forbid you get a rocker or valve collar breakage, this will stop the broken parts causing serious damage to the bottom end, that's the theory anyway......

Is the paint something special or just black paint?

Do you have any more information on the black finish? Looks superb.

The black finish on the cases while not to everyone's taste was very much a personal thing. While the original RSR's ran the fragile magnesium 7R cases, the turbo case as used here has been homologated for use by the FIA as a replacement for racing. The mag case with a chromate finish goes very dark and of course the aluminium case when refinished is very bright so that set me thinking about a black finish. I decided on this one as it's used by the Formula One teams for their gearbox housings as a low friction protective coating and is very thin, just 20 microns, so it's much thinner than paint and doesn't have any inherent heat dissipation problems.

regards, Mike

[Mike_Moore]

Thought I'd just update this thread with the latest engine build picture, and now while we wait for the final work on the
cams to be done, we started on the gearbox.



The gearbox will be done to RSR spec and with the cases freshly chromated we started to put the gear cluster together
with the new ratio's, the modified input shaft with the collar and a wevo 'teddy bear'.



The gearbox will have an oil pump spray bar set up working from the two gears in the end casing which has been
machined to take them. I've had the whole kit made including the gears, spray bars and re-casting the RSR and RS
pump gear end covers.



You can see the spray bar running along the left side of the gears here,



holes spaced to match the gears



and then through into the diff casing for the crown wheel and pinion.

[Mike_Moore]

The selector forks are original RSR in that the shafts are threaded to ensure no movment in the fork and the bolts will
be lockwired,



as are any bolts with a chance of loosening.



The diff especially looks cool as it sits in place for the final time after setting the pre-load and backlash.



The final piece of detail for the moment is the RSR breather which has a pipe that runs down the side of the casing.