BlueTR3A-5EKT Posted March 18, 2023 Report Share Posted March 18, 2023 Mount it over the engine Marco? Quote Link to post Share on other sites
Peter Cobbold Posted March 18, 2023 Report Share Posted March 18, 2023 23 minutes ago, BlueTR3A-5EKT said: Mount it over the engine Marco? That's a sucker not a blower !! Quote Link to post Share on other sites
Peter Cobbold Posted March 18, 2023 Report Share Posted March 18, 2023 1 hour ago, Z320 said: Hi, today I did some measurement on the cars engine, found the head about 85.3 mm high. Minus about 1.7 mm for the head gasket = 84.6 mm = 3.33" (84.582 mm), ergo the head is original. Like this head (84.58 mm) on a worn TR4a engine, which I bought some years ago because of the crankshaft and head. I could do what I never wanted to do: rebuilt the hole engine. With a different gasket I could reduce the compression ratio and do a quick swap. Some items fitted, with the dynamo back on the engine I hope to find a idea how to fit the SC and how to fit which belt. Ciao, Marco A poly v belt fitted in front of the existing pulley would be simplest if the chassis x-member does not conflict. Dont forget an idler pulley to help wrap around the s/c pulley and for tension adjustment. I doubt a longer single belt of the existing type would drive the s/c , it needs several horse power under boost. But that's what I'd check first. Peter Quote Link to post Share on other sites
Z320 Posted March 18, 2023 Author Report Share Posted March 18, 2023 Hi Peter, thank you for the really good idea for a poly-V felt in front of the standard or narrow belt. I just checked this, sadly the cross tube between the domes doesn’t allow this. What do you thing about a short belt from the water pump pulley to the SC pulley? That would be also simple to do. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 18, 2023 Report Share Posted March 18, 2023 11 minutes ago, Z320 said: Hi Peter, thank you for the really good idea for a poly-V felt in front of the standard or narrow belt. I just checked this, sadly the cross tube between the domes doesn’t allow this. What do you thing about a short belt from the water pump pulley to the SC pulley? That would be also simple to do. That is how theJudson kit operated. Not sure how long the water pump bearings last! Quote Link to post Share on other sites
Z320 Posted March 18, 2023 Author Report Share Posted March 18, 2023 I would do a basic improvement on the water pump pulley, which is anyway sensefull. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 18, 2023 Report Share Posted March 18, 2023 28 minutes ago, Z320 said: I would do a basic improvement on the water pump pulley, which is anyway sensefull. Your fiddle would be getting the water pump pulley the right diameter driving the sc. The sc pulley can be varied in size too. However, as Pete has remarked…..get it wrong and the thing will not pump enough to even satisfy a basic non supercharged engine demand. Been there done that. I ended up changing a friend's crank pulley for one from a Volvo 240 to get the right sc rotational speed. It corrected the lack of boost a professional had set the car up with. Quote Link to post Share on other sites
Waldi Posted March 19, 2023 Report Share Posted March 19, 2023 10 hours ago, Z320 said: What do you thing about a short belt from the water pump pulley to the SC pulley? Hi Marco, maybe I do not understand you, but if the belt from crack to waterpump remains standard width/design I don’t think this can handle the power it needs to transmit. Waldi Quote Link to post Share on other sites
Z320 Posted March 19, 2023 Author Report Share Posted March 19, 2023 (edited) Hi Waldi, thank you for your worry, but this is no need. On the MB 230 SLK only a 6PK multi-V belt (21.36 x 4.6 mm) pulls the SC (+waterpump + alternator) In my opionion the TR 4 cylinder "typ 20" belt, a MONSTER, total overdo, a typ 10 or 13 would do the job ("narrow belt"). Ciao, Marco Edited March 19, 2023 by Z320 alternator, not dynamo Quote Link to post Share on other sites
Z320 Posted March 19, 2023 Author Report Share Posted March 19, 2023 (edited) Back from the garage, I have 17 mm space between the typ 20 belt and the cross tube. I see 3 options: #1 The use of one 6PK multi-V belt like on the MB 230 SKL. I have to produce (or find) 4 new 6PK pulleys, I guess the 140 mm one on the crank is much to big for the SC on the TR4A. To make it smaller gives less power on the water pump and dynamo, so the one on the SC must be bigger. Also I have to fit at least 2 deflection (correct therm?) pulleys because 1 belt without them on 4 pulleys is not possible to do. BTW: for good service the belt tensior of the Moss set is the wrong one and on the wrong position. But this is counting peas, very likely this doesn' matter at all and they use it as a deflection pulley. #1 is the most efford! #2 Fit two modern typ "13" belts next to each other, one for the TR water pump and generator, one for the SC. I have to produce 5 pulleys, but I can make the one for the SC on the crank smaller. My second choice at the moment. #3 I let all pulleys as they are and further use my typ "20" belt for the TR pulleys. Also use the 6PK pulley from the SC and the magnetic clutch, fit a suitable 6PK pulley on the waterpump pulley and an automatic tensior roll in the return trum (below). This is only 1 new pulley needed to determain and make and minumum efford. And if it was used by Judson? That's my thoughts at the moment, better ideas are welcome. Ciao, Marco Edited March 19, 2023 by Z320 Quote Link to post Share on other sites
Peter Cobbold Posted March 19, 2023 Report Share Posted March 19, 2023 Remember that the blower only needs 'several' horsepower when it is delivering boost. Most of the time in road driving ( typically 90%) it will need very little power to keep it spinning. Perhaps the water pump could be fitted with a poly-v belt pulley dedicated to driving the blower ? However the orignal drive belt might slip on the wp pulley under boost. Bearing life might be compromised but the wp is not notoriousl unreliable, or is it? Peter Quote Link to post Share on other sites
Z320 Posted March 20, 2023 Author Report Share Posted March 20, 2023 (edited) Good morning Peter, the TR water pump and it’s pulley could benefit from an improvement, but sadly yesterday evening I was not able to find the suitable bearing for this. This makes me puzzling. Last night, going to bed, I also puzzled on Alan Allards book, page 55, figure 30. Is this correct? In my words: to get a boost ratio of 1.5, with attention of the sc efficiency of 65% I get a smaller factor for the amount of needed air? The factor must be higher (1.5 / 0.65 = 2.3)? Sorry me, if I understand this wrong… Not a sleep well book…. Ciao, Marco Edited March 20, 2023 by Z320 Quote Link to post Share on other sites
Peter Cobbold Posted March 20, 2023 Report Share Posted March 20, 2023 Marco, My apologies I forgot to check the earlier sums. The boost ratio is what we calculate from the pulley ratio and the volumetric efficiency for the engine. That compressed air will be heated by a factor that depends upon the blower's design ( the more turbulence it creates, the more heat). This is 'adiabatic efficiency' ( the 65% you mention) and that reduces the air density. The relationship is shown in the graph on slide 34 of the talk. So for a boost ratio of 1.5 (ie ca 7psi gauge boost) the density ratio for 65%AE will be ca 1.3, which should deliver 30% more power. Quote Link to post Share on other sites
Ian Vincent Posted March 20, 2023 Report Share Posted March 20, 2023 8 hours ago, Z320 said: Good morning Peter, the TR water pump and it’s pulley could benefit from an improvement, but sadly yesterday evening I was not able to find the suitable bearing for this. Hi Marco, When I rebuilt my water pump I couldn’t find a suitable bearing so I got a friend to run me up a new shaft suitable for the available bearings. The idea and sketch of the new shaft was provided by a long time contributor to this forum called Don (I forget his surname). I will see if I can find it later this evening and if I’m successful I will post it here. Rgds Ian Quote Link to post Share on other sites
Z320 Posted March 20, 2023 Author Report Share Posted March 20, 2023 Hi Ian, thank you but please do nothing, I tell you later. Quote Link to post Share on other sites
Z320 Posted March 20, 2023 Author Report Share Posted March 20, 2023 Dear Peter, thank you so much for enlighten me! Now I understand. The issue with the pressure and desity ratio is what I assumed earlier this thread: how much of the boost is compressed air and how much is expanding air because of heat. After I found out what is "CFM flow" page 53-57 appears clear to me. Allow me to do and show you my calculation, please be so kind and correct me: - my TR4A's cylinder capacity is 2.136 liter - natural aspirated it need 2.136 l x 0.5 x 0.8 = 0.854 l each turn of the crankshaft - assume I want only 4.5 PSI boost absolute (1.3 bar), the boost ration is 4.5+14.7/14.7 = 1,3 (metric system is so lovely - ergo the air density ratio according fig 30 is about 1.18 - the needed air for 4.5 PSI boost is 1.18 x 0.854 l = 1.007 l each turn of the crankshaft - the M62 SC flow is 1.016 l each turn Result: For 1 turn of the crankshaft I need 0.992 turns of the M65 SC) For 7 PSI from the books example I need 1.275 x 0.854 l = 1.08885 / 1.016 = 1.07 turns That's not much difference! Quote Link to post Share on other sites
Z320 Posted March 20, 2023 Author Report Share Posted March 20, 2023 (edited) Hi Ian, to rebuilt an old TR2-4 water pump with new bearings is not the issue, they are called "6203-2RS d16". They are 20 mm wide, not 14.3 mm (9/16"), so the spacer between has to be shorter. Knowing this you can browse the web and choose the best offer. I never had a damaged water pump bearing. "The problem" is the water pump housing and pump situated in front of the TR engine, not backwards like the dynamo. This brings the water pump pulley very much out of line to the crank pulley, the result sadly is a "barrel" pulley! Have a look and you will see. The shaft goes the hole way through the "barrel", while the forces bear on the other end. This makes the "barrel" tumble and it is constantly bending the end of the shaft and woodruff key and punching the washer below the nut. All "OK", as long the pulley has a tight fit on the shaft, the MASSIV washer is fitted and with low forces. How can I be shure this construction can drive a SC? With a bearing between the pulley and the "nose" of the waterpump, with this the pulley runs on the pump housing. Suitable would be a di/do = 50/70/16 mm, but this is not avaible. I see no way to get a 50/80/16 fitted, called "6010". Others / smallers are "6810" and "61811". Any ideas welcome! Ciao, Marco Edited March 21, 2023 by Z320 Quote Link to post Share on other sites
RobH Posted March 20, 2023 Report Share Posted March 20, 2023 16 minutes ago, Z320 said: Any ideas welcome! Maybe a bit radical but how about scrapping the mechanical water pump altogether. Fabricate a substantial pulley arrangement with the bearing further back, that will fit to the existing mounting and which will also blank off the hole in the water pump housing. Use an electric water pump fitted in the return pipe from the radiator. https://www.demon-tweeks.com/uk/davies-craig-ewp115-electric-water-pump-7000487/ Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 20, 2023 Report Share Posted March 20, 2023 45 minutes ago, RobH said: Maybe a bit radical but how about scrapping the mechanical water pump altogether. Fabricate a substantial pulley arrangement with the bearing further back, that will fit to the existing mounting and which will also blank off the hole in the water pump housing. Use an electric water pump fitted in the return pipe from the radiator. https://www.demon-tweeks.com/uk/davies-craig-ewp115-electric-water-pump-7000487/ Beat me to it Quote Link to post Share on other sites
Peter Cobbold Posted March 21, 2023 Report Share Posted March 21, 2023 16 hours ago, Z320 said: the needed air for 4.5 PSI boost is 1.18 x 0.854 l No. To get 4.5psi boost you need 1.3 x 0.854 L The boosted air is heated and that heat contributes to the psi figure. That figure is what you use to calcualte the pulley circumference ( same as diameter). *** Even a 100% Adiabatic effic compressor will heat the air. Boyle's law. PV=RT. Of that 4.5 psig boost only 65% will be air because the density ratio is 1.18 from the graph. So the torque gain =20% ==== ***I think I would go for a bit more boost, say 7psi. When the crank is at low rpm, the blower will also be operating very low in its rpm range, and back-leakage which reduces booost may be present. It may be that the full 7 psi boost does not develop until above ca 3000 rpm crank and above that combustion is too fast for detonation to occur. If it knocks there are remedies such as boost-retard. I use a pressure switch to actuate a solenoid that pushes the ignition points anticlock a few mm. Peter Quote Link to post Share on other sites
Z320 Posted March 21, 2023 Author Report Share Posted March 21, 2023 Thank you Peter, I guess I have to calculate a likely diameter, test and modify it. Quote Link to post Share on other sites
Peter Cobbold Posted March 22, 2023 Report Share Posted March 22, 2023 2 hours ago, Z320 said: Thank you Peter, I guess I have to calculate a likely diameter, test and modify it. Marco, Testing can only be done driving or on a rolling road. If the engine is not loaded you wont see any boost, the rpm will just soar. If the boost should prove to be too much and detonation cannot be avoided than a pulley change would be needed. However with your workshop skills there is water injection for raising the effective RON octane to ca 105. https://supertrarged.wordpress.com/2014/11/10/tr6se-28-water-injection/ https://supertrarged.files.wordpress.com/2016/01/tr6se-35-water-injection-revisited.pdf With WI you could probably run 10psi of boost safely at 3000 rpm................... That's the fun of supercharging ! Peter Quote Link to post Share on other sites
Z320 Posted March 22, 2023 Author Report Share Posted March 22, 2023 5 hours ago, Peter Cobbold said: Marco, Testing can only be done driving or on a rolling road. If the engine is not loaded you wont see any boost, the rpm will just soar. Peter Peter, that’s good news! If the SC runs too fast starting the engine will not end in a big explosion. Ciao, Marco Quote Link to post Share on other sites
Peter Cobbold Posted March 22, 2023 Report Share Posted March 22, 2023 7 hours ago, Z320 said: Peter, that’s good news! If the SC runs too fast starting the engine will not end in a big explosion. Ciao, Marco That reminds me, another trick to limit max boost, used by Allard, is to use a restrictive air filter. Peter Quote Link to post Share on other sites
Z320 Posted March 23, 2023 Author Report Share Posted March 23, 2023 (edited) Hi, yesterday I compared classic type "20", "17" and modern V-belts with serveral TR engine, generator and waterpump pulleys. The classic belts are angled 34°, modern V-belts 40°, while I measured all TR pulleys angled only 30°-28°! Ergo the belts are running not on their full surface IN the pulleys but only with a very small line ON the rim of the pulleys..... This works anyway but makes me wonder. Is there an explanation for this, please? Ciao, Marco Edited March 23, 2023 by Z320 Quote Link to post Share on other sites
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