Stagpowered Posted February 9, 2019 Report Share Posted February 9, 2019 I bought my TR250 back in 1992 and ran it as a fake TR5 for a few years before fitting my first Stag engine. My first engine had 165bhp, the second one 216bhp. Always said I would replace the TR5 badges with TR250 ones when I got 250 bhp out of it. Looks like I am going shopping at Stoneleigh tomorrow! All the internal engine components are standard parts with the exception of reprofiled 285 degree cams, 10.5 : 1CR, runs on regular unleaded petrol. Neil Quote Link to post Share on other sites
JochemsTR Posted February 10, 2019 Report Share Posted February 10, 2019 Very impressive! Just out of curiosity....Stag engine just drops in place or are there any mods to frame and body required? Jochem Quote Link to post Share on other sites
JochemsTR Posted February 10, 2019 Report Share Posted February 10, 2019 PS....what is happening between 1.800 - 2.500 range? Is there still some tuning regarding mixture required? Quote Link to post Share on other sites
Steves_TR6 Posted February 10, 2019 Report Share Posted February 10, 2019 Very nice! what gearbox and diff are you running Neil ? steve ps, i’ve always fancied a v8...... Quote Link to post Share on other sites
Drewmotty Posted February 10, 2019 Report Share Posted February 10, 2019 There is a newly completed TR4 with a 2.5 Daimler V8 for sale in North Devon Quote Link to post Share on other sites
Drewmotty Posted February 10, 2019 Report Share Posted February 10, 2019 There is a newly completed TR4 with a 2.5 Daimler V8 for sale in North Devon Quote Link to post Share on other sites
ianc Posted February 10, 2019 Report Share Posted February 10, 2019 Those of us who were members in the 1970s will recall John Hanna's sidescreen TR with its Daimler 2.5 litre V8 engine - very torquey and impressive! Ian Cornish Quote Link to post Share on other sites
Stagpowered Posted February 10, 2019 Author Report Share Posted February 10, 2019 8 hours ago, JochemsTR said: Very impressive! Just out of curiosity....Stag engine just drops in place or are there any mods to frame and body required? Jochem The only mods needed to the chassis were some extra brackets for the Stag engine mounts which fit more or less directly below the straight six mounts and conveniently tie in to the tops of the wishbone mounting brackets which usefully strengthens these. The upper engine mount holes are pretty much where the bottom ones are for the straight six. The left hand corner of the bulkhead has to be cut back in a straight line with the edge of the battery mounting area and this carries down far enough to clear the left hand water transfer housing. I think I may have had to slightly cut back the web that runs from the bulkhead to the inner wing where it bolts to the chassis on the left hand side but it is so many years since I have done it I can't remember exactly how much, but only 1-2 cm. The steering column needs a joint in the middle to go around the engine block, I found a Dolomite lower steering joint did the job (I had lots of Dolomite spares at the time), and a shortened TR top section. I bodged up a centre bearing from an old trunnion bush and a bit of steel tubing with some rubber between them and bolted it to the inner wheel arch. This was supposed to be a temporary measure before I made a proper one, but it has lasted 20 years and nearly 100,000 miles so I am in no rush to change it! Gearbox is Stag so fits just where the TR one does, and back axle is cobbled together from a PI saloon case with Dolomite Sprint internals simply because I had them and the original diff had shed several teeth when I bought the car. Again, these have covered about 100,000 miles since I first put it together on top of the 146,000 miles the diff had covered when I removed it from the Sprint axle, though I did treat it to a new set of bearings a couple of years ago. Diff mounts are strengthened in the usual manner. Quote Link to post Share on other sites
Stagpowered Posted February 10, 2019 Author Report Share Posted February 10, 2019 8 hours ago, JochemsTR said: PS....what is happening between 1.800 - 2.500 range? Is there still some tuning regarding mixture required? Unfortunately that is just a characteristic of the power band of the engine, I am using quite large bore manifolds with 38mm primary pipes and 44 mm secondaries which works wonders for the top end but at the expense of bottom end torque. It should rev higher than it does but starts missfiring above 6500rpm. This has been a common theme with the last two engines I built using these cams but the misfire was not so obvious as the power was tailing off anyway. The rolling road operator is pretty sure it isn't fuel or ignition from the readouts he is getting, so best guess at the moment is the onset of valve bounce as the standard springs are still being used. I am going to see if I can get hold of some early Jag XJS cam followers as these are 15 grammes lighter than the Stag cam followers, and possibly top hat shims rather than the heavy pallet shims. If I can't locate any I will try some slightly stronger valve springs. Below is the previous rolling road graph when I disappointingly got less than the 246 bhp I got from the last engine I built that is fitted to my 1972 Stag. On checking the cam timing I found too much advance, particularly on one bank where I had stupidly bolted my carefully redrilled cam sprocket on back to front giving 6 degrees more advance than I was aiming for. The curve is pretty much the same shape but with far better bottom end torque. Minimum ignition advance with the high torque profile was 9 degrees, but when the cams were timed in correctly and the bottom end torque dropped a minimum of 14 degrees advance was needed, reflecting the drop in volumetric efficiency. I have drawn on the 253 power and torque curves in blue. The next engine I build will have more compression so I should be able to get back the lost bottom end and gain a bit more at the top end, but that is a year or two away yet as I have to re-spray my Stag engined Triumph Estate this Summer Quote Link to post Share on other sites
Motorsport Mickey Posted February 10, 2019 Report Share Posted February 10, 2019 Good result Neil, you've been hunting the 250hp down a couple of years now, ...not surprising, the posting name of Flying Farmer on the Stag owners club forum gives a hint on how your "day job" impinges onto your car development time, you must have a time machine, I don't know how you manage it. regards Mick Richards (Micky) Quote Link to post Share on other sites
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