mfperks Posted March 1, 2015 Report Share Posted March 1, 2015 Being a bit ckeeky here, but this forum has some serious gurus. Most cooling systems with a thermostat have a bypass hose to keep the coolant moving round the engine until the temperature is up to spec. Currently I have to run a waterpump, but have no thermostat and no bypass hose. (we are talking 1936 here) Could using an in-hose thermostat but drilling a 1/4" hole through the closure plate work? I am hoping It would slow the circulation to allow for rapid heating till the stat opened. Discuss? MIke Quote Link to post Share on other sites
Alec Pringle Posted March 1, 2015 Report Share Posted March 1, 2015 That sounds like The Riley is up and running . . . . . ? Come on Mike, pictures please !! Good theory, the hole size would have to be trial and error, and keep a thermometer on the head whilst you experiment . . . . Cheers Alec Quote Link to post Share on other sites
Guest ntc Posted March 1, 2015 Report Share Posted March 1, 2015 Discreet electric water pump? Quote Link to post Share on other sites
mfperks Posted March 1, 2015 Author Report Share Posted March 1, 2015 Electric waterpumps are a no no, "Against the rules dear boy". Re the photo request, Alec, I have forgotten how this forum works! But -- I hope -- Quote Link to post Share on other sites
peejay4A Posted March 1, 2015 Report Share Posted March 1, 2015 Oh, that is lovely. Quote Link to post Share on other sites
Paul Down Posted March 1, 2015 Report Share Posted March 1, 2015 Presumably cooling is by thermo-syphon , i.e. no fan or water pump. I have had a similar problem on my 1936 Morgan. Be careful putting anything in the main cooling circuit as any restriction can cause it to boil very quickly ( dont ask how I know) as Neil suggests an in line electric pump such as the Davis Craig work very well and the small version only pulls around 1.7Amps. but it has to run continuously, if you switch it off even for a short time you get quickly to the point of no return and it boils because when not running it effectively stops all water flow. I tried an electric fan but that was a waste of time. I am about to install the pump in bypass around a main cooling hose so that the thermo-syphon is unaffected. If you have adequate cooling when up to temperature I would tend to leave it as it is as mostly overheating is the main problem. I believe the problem for these really old cars is that the modern fuel burns hotter and of course much more traffic on the roads now, Quote Link to post Share on other sites
Peter Cobbold Posted March 1, 2015 Report Share Posted March 1, 2015 Won't the thermostat obstruct flow even when fully open, compared with an uninterrupted hose? Cooling might be impaired. When cold, the water pump would have to force all its flow through a 1/4" bore wont its outlet pressure rise too high? What about a manually-operated 2way valve in the top hose? with two positions: open to top of rad when hot; open to bottom of rad when cold ( ie rad top to bottom hose bypass) Quote Link to post Share on other sites
Alec Pringle Posted March 1, 2015 Report Share Posted March 1, 2015 Well done Mike, the Riley has come on a treat since I last saw it - when are we up for a test run ? Cheers Alec Quote Link to post Share on other sites
mfperks Posted March 2, 2015 Author Report Share Posted March 2, 2015 The thermo-syphon should have worked, but didn't. That would have been ideal, it is a great system when working. So I restored and fitted the original waterpump, with the obvious cosquence of taking forever to warm up. Another issue we have with the beast, is violent lurching on acceleration, up to a point all is well, then it seems to aquire another 4 cylinders and an open throttle. Rear end (the car) squats and the whole thing twists, not fun! Captain Kangaroo lives. I have put thicker oil in the dashpots and changed the plugs and we have to do a re test. The problem, as Alec knows, is we are on a one way system, once on the road we have to do the entire lap, not good as there is always someone up your bumper! This is the current cooling system: Quote Link to post Share on other sites
Paul Down Posted March 2, 2015 Report Share Posted March 2, 2015 Mike, That is is a very tidy engine bay. Are you a member of the VSCC? As you mentioned an electric pump was not permitted I presumed you would be using the car competitively. There are scores of VSCC members with early Rileys and Riley Specials in the VSCC and the Technical Forum is a mine of information, probably worth you joining even if only for a year to get your car sorted: www.bertram-hill.com http://www.vscc.co.uk/ Quote Link to post Share on other sites
mfperks Posted March 2, 2015 Author Report Share Posted March 2, 2015 Thank you for the kind words Paul, Pete also. We are in the VSCC but currently without the funds to indulge fully! One day ---- Quote Link to post Share on other sites
barkerwilliams Posted March 2, 2015 Report Share Posted March 2, 2015 Is viscous fan allowed? Quote Link to post Share on other sites
Peter Cobbold Posted March 2, 2015 Report Share Posted March 2, 2015 Mike, It should warm up much quicker when driving compared with tickover or stationary revving. Wait and see what it does in summer heat? Have the SUs got the correct piston springs - too weak would allow the pistons to lift excessively. But sudden surge of power doesnt suggest carb pistons lifting too fast to me- it would more likely run really rough before the surge comes. I guess its going to need roughly 30-35deg BTDC spark at 3000rpm ?? But If the ignition is giving 30-35 from tickover then thats too much lead. So could the the sudden coming on song be related to spark. No centrifugal advance, manual retard? Peter Quote Link to post Share on other sites
MikeF Posted March 2, 2015 Report Share Posted March 2, 2015 I am by no means a guru, so am unconfused by any prior knowledge. What if you retain the original pump with a by pass perhaps with a valve [such as a heater control]. Open when cold shut when hot. That would shorten warm up time, but not impede full flow when hot. Beautiful car. Mike Quote Link to post Share on other sites
mfperks Posted March 2, 2015 Author Report Share Posted March 2, 2015 Peter, I am thinking along those lines myself, timing could cause some very strange behaviour. The dizzy is new and fitted with an advance curve suited to this engine config, ie near race. There is no manual adjustment, just the bob weights and springs. No vacuum control either. Although it has a preselect gearbox, there is no centrifugal clutch and precious little left of the flywheel, so if something manifests it will be interesting ---- More to check on that front, with no access to the flywheel we are back to the good old timing stick, or in this case a DTI down the plug hole. I like yours and MikeF's idea of a control valve, the valve idea has much to recommend, will need to look into that, warmer by the end of this week! Quote Link to post Share on other sites
BlueTR3A-5EKT Posted March 2, 2015 Report Share Posted March 2, 2015 This is not a solution but an observation from working with classic car parts sourcing. I was told by a cooling engineer at Weston Thompson (UK thermostat maker) many moons ago when I was attempting to source a replacement for the bellows thermostat that they specified most modern engine cooling systems without a bypass, only a bleed hole was required in the 'in hose' thermostat to allow the cooling system to self bleed. The issue of removing a thermostat from a system designed for one was also discussed and I had confirmed that removing a thermostat may even cause overheating. It operates not only as a temperature control device but is also designed with the system to restrict water flow through the radiator - or you pump boiling water straight through the radiator and return it insufficiently cooled to the engine water inlet. Hence the thermostat blanking sleeve used on many race application Austin/Morris/MG/Austin Healey engines, and specified by Abingdon ST dept. Part no 11G176 link https://www.google.co.uk/search?q=mini+thermostat+blanking+sleeve&rlz=1C1ASRM_en-GBGB617GB617&espv=2&biw=1280&bih=871&tbm=isch&imgil=rujLI7QVXd-NAM%253A%253B77yq_Z5rblS0fM%253Bhttp%25253A%25252F%25252Fwww.minimania.com%25252Fpart%25252F11G176%25252FThermostat-Blanking-Sleeve-mini-Sprite--Midget&source=iu&pf=m&fir=rujLI7QVXd-NAM%253A%252C77yq_Z5rblS0fM%252C_&usg=__h-qn7FzZDCZJ0PSGWoxbON7ODXY%3D&ved=0CEEQyjc&ei=74n0VNC-Homu7gb4tIEQ#imgdii=_&imgrc=rujLI7QVXd-NAM%253A%3B77yq_Z5rblS0fM%3Bhttp%253A%252F%252Fwww.minimania.com%252Fimages_temp%252F80060000111g176.jpg%3Bhttp%253A%252F%252Fwww.minimania.com%252Fpart%252F11G176%252FThermostat-Blanking-Sleeve-mini-Sprite--Midget%3B800%3B600 Peter W Quote Link to post Share on other sites
Peter Cobbold Posted March 2, 2015 Report Share Posted March 2, 2015 Near race engine .....Its not a distributor intended for use with methanol? That would give a lot more advance than petrol needs, until the rpm rise. Quote Link to post Share on other sites
Cew Posted March 2, 2015 Report Share Posted March 2, 2015 (edited) Hi Mike. I don't know if this is what you are after,it is from a 1951 Mercedes Benz 170VA.I bought it new in the early '70s and it never got used(it is still in it's original packaging. It is about 5" long and the pipe diameters are 1 1/4". The thermostat operating temperature are,unfortunately,unknown to me.The thread size on the side will probably be metric. Your welcome to have it as it has been languishing in my garage for 40 odd years.The engine in the car was a 4 cyl. side valve of about 1800cc,with an aluminium head and an updraught solex (I think) carb.,. Edited March 2, 2015 by Cew Quote Link to post Share on other sites
greasemonkey Posted March 2, 2015 Report Share Posted March 2, 2015 Mike, Am I right in thinking that the original thermo housing would not line up with the top hose from the rad - hence you can't use the original housing which would solve the issue?? Phil. (Riley 12/4 special owner too!) Quote Link to post Share on other sites
Cew Posted March 2, 2015 Report Share Posted March 2, 2015 Not a very good picture but a similar arrangement of top hose with thermostat installed. Quote Link to post Share on other sites
mfperks Posted March 3, 2015 Author Report Share Posted March 3, 2015 From the top! Peter W, that opened a whole new can of worms! There is a massive amount on that subject, which I admit is new to me, still delving into that side of things. Peter, I think the distributor is for petrol, or at least it should be -- the engine white metalling and associated engineering plus the dizzy was done by a well know Riley man in Southend, he also commisioned same as part of the warranty agreement, so it should be right. But it does need to go on a rolling road for final setting. Phil, spot on! I have a couple of different housings, none even close. It should be goo when sorted though. Photo of yours? Clive, that could well be worth trying, I believe that those thermostats close the byepass loop as they open, which is what is needed. PM sent. Thanks everyone for the ideas, sometime one gets stuck in a mind set, fresh thoughts help to break that trap. Quote Link to post Share on other sites
oldtuckunder Posted March 3, 2015 Report Share Posted March 3, 2015 How about one of these for the top hose £12.50 http://www.dmgrs.co.uk/products/rover-75-mg-zt-cdti-inline-thermostat-89-degrees Quote Link to post Share on other sites
mfperks Posted March 4, 2015 Author Report Share Posted March 4, 2015 Things have sure changed since I was a lad ----- If you have a particularly 'hard' top hose, you may need to use a little lubrication to fit the thermostat. Quote Link to post Share on other sites
SpitFireSIX Posted March 4, 2015 Report Share Posted March 4, 2015 *************************** The issue of removing a thermostat from a system designed for one was also discussed and I had confirmed that removing a thermostat may even cause overheating. It operates not only as a temperature control device but is also designed with the system to restrict water flow through the radiator - or you pump boiling water straight through the radiator and return it insufficiently cooled to the engine water inlet. ************************** Hi, I believe and from experience, if you remove a thermostat from a cooling system, you will likely suffer overheating problems. At high RPM the thermostat creates a restriction in the cooling system and raises the pressure in the cylinder head. As the cylinder head is at a higher water pressure localised boiling is reduced. remove the thermostat completely and you will suffer boil over. Too fast a flow thru a radiator = less cooling, is a myth. Maximum flow = maximum cooling. Maximum flow = point before pump cavitates This is true. Have you thought about using a three port thermostat?. Coolant will circulate within the engine until the thermostat opens and then sends coolant thru the rad. Cheers, Iain Quote Link to post Share on other sites
mfperks Posted March 4, 2015 Author Report Share Posted March 4, 2015 Hi Ian, the cooling system in these old designs was meant to function on a purely thermosyphon system, ie, when the water got hot it circulated on it's own, until that point no circulation, no need. around 1935 - 7 the outputs were increasing so a waterpump was added running in this case, from a camshaft. I wasn't going to win any races for pumping speed and was a face seal design, no bearings as such. However, using a pump dictated a thermostat which was of the bellows and flap style, this also closed the bypas loop so that the pump retained some sort of efficiency. System pressure is about 1 - 2 psi max. From what I gather with the "ballanced" three port type, this was similar to a standard thermostat, but has an extra spring to counter the pressure from modern pumps, so is very accurate in it's opening. What it does not have as far as I can determine, is any way to close the bypass loop, which is definitely required. Cew has a unit that could be the saviour of the day, I will be trying this over the next few weeks, and if successful, will let you know. Quote Link to post Share on other sites
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