Spitfiredriver71

It's an MS3. I am also playing around with a Bosch knock sensor. I have made a circuit to filter the low frequencies out and just need to fine tune the gain. Then I can advance the timing a bit without having to worry.

I tried connecting the rocker cover to the air filter side of the throttle body today and after 15 minutes not a drop of oil. The port on the throttle body looks like it acts like a venturi so seems to work for my needs. The piping was just what I had lying around to do the test so will need sorting but I have attached a photo. I tried to make the manifold look similar to a TR6 plenum.

Hello Clive I did some testing again today and with the breather filter removed, the oil stopped coming out. As soon as I put it back on, oil came out the dipstick. I can blow straight through the filter and it offers next to no restriction but without it connected it does not leak. I was thinking the same thing earlier about connecting it to the throttle body. There should be a slight vacuum as the main air filter will cause some restriction. As it would be on the outside of the butterfly it should not affect the vacuum reading to the ecu. I will try the leakdown test on another engine when I get the chance. It may be that my tester is rubbish. The bores were honed when I rebuilt it. It was a replacement engine so I stripped it as a precaution and as everything was in spec I just replaced bearings and piston rings.

Clive I was trying to avoid connecting it to the manifold as I think it will upset the vacuum. It used to cause problems with the carbs which is why I fitted the lambda sensor in the first place. With it connected on overrun the car would stall (really lean) With it vented it worked fine. Ian It was at 40psi. The instructions said to set the compressor to between 40 and 60psi. I will try warming it up this afternoon and trying again at a higher pressure. It's certainly not a high quality tester but I was hoping to find a definite problem. It was just about in the green on the gauge but I thought it should be higher considering the mileage since the rebuild.

I will try removing the filter this afternoon. Has anyone done a leakdown test? I did have a catch tank on a previous setup but it still had a filter on the output. This is an ongoing issue over many years. I might be trying to achieve the impossible with a triumph that does not mark it's territory. Since the fuel injection I drive it a lot more and the oil everywhere I park is getting really annoying.

It is a mark Iv but is a long way from standard. The rocker cover is the aftermarket aluminum Style and I just have a filter on the breather. The car is running fuel injection and fueling is good. It used to have hs4 carbs that sucked the excess crank case gasses but has always leaked oil. I built the bottom end 7 years ago and I wonder if I got the ring gaps wrong as it has excellent compression, starts first time and does not burn oil. It just seems to push it out. If it take the filler cap off the oil leaks stop and it will sit on the drive running for 30 minutes without losing a drop.

Mine is just venting to atmosphere thought a small filter attached the the rocker cover. There just seems to be to much for the filter to vent.

I have an oil leak from my spitfires dipstick. The car does not do many miles each year and has done less than 10,000 miles on the current pistons and rings but I seem to have excessive blow by. On a standard compression tester I get good readings on all 4 so was advised to try a leak down test instead. I am getting 30-40% leakdown. I assume this will be a ring problem as the air is coming out of the dipstick but wondered what numbers are realistic for an old triumph. Modern engines achieve 10-15% but I assume they run tighter tolerances. There are no marks in the cylinder walls and there is no measurable step at the top. The car runs and drives well apart from its incontinece. Any ideas? Alan.

Does anybody know what the clearances are for the main and bigend bearings for a Spitfire IV 1300? While I have the engine out I thought I would check the bearing tolerances with some plasti gauges.

Hello Pete So I do not need it for my J type then.

I have managed to get a new mainshaft for my 3 rail spitfire gearbox with the correct drive for my J type overdrive, but the clip from the old shaft looks very small on the new one as the gap is much larger. The clip is in between the 2 shafts in the photo. On the darker broken one it fits the gap after the splines but the machined area on the new one is much bigger. What does the clip do and is it needed? I have not found it in any catalogue yet.

Does anybody know if you can buy just the front part of the floor pans for a triumph spitfire in the UK. There are multiple options in the US but have only seen complete floor panels over here. I have the seats out and from the support back it solid but the front part has had water trapped under the carpet at some point and is a bit thin in places. Alan

Hello Pete I spoke to various companies including the overdrive specialists and nobody has a main shaft for a 3 rail gearbox with J type overdrive. Paul I spoke to Mike Papworth and discussed doing exactly what you have.

On a side note what is the recommended gap for the Baulk rings?

After cracking the mainshaft on my gearbox a few weeks ago I have been trying to sort out what is good and what needs replacing. The photo below shows the 2 sets of gears I have, however It has been a game of spot the difference. One has a thrust washer that locates on a ball bearing and the bush for 2nd gear and thrust washer for 3rd gear are one part. Does that mean the end float should be the same on both? Also there is a lot more movement on the synchro hub on the right, you can see the gap in the photo but 2nd gear seems to line up although it is wider. The only person that can supply the shaft seems to be Mike Papworth but I do not know which thrust washer I will need to use, ball bearing or not? Another question is which synchro hub should I use? the one on the right has rounded off edges in the first gear direction but the one on the left has a damaged tooth. Any advice gratefully received. Alan