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Jan 24, 2012 13:05:57 GMT
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Hi everyone, Just checking if there are any common problems / things to check on a 1725 Rootes motor. Normally ok (low powered in the Estate but I'd expect that) but have noticed a few times it's overheating after a long haul. Yesterday was fairly typical, running fine for a few weeks, then started to pressurise and blow off steam from the radiator cap. - the car was making hard work of climbing a steep bank with dogs + a load of firewood in at the time  It's a 1725 iron head motor, single carb, electronic "points" inside the original (Lucad 25D ?) distributor, working overdrive, etc, and I fitted a new water pump last year as the old one ws an antique with shot bearings  Ignition timing seems to be on the stock marks, is it just a case of changing to suit unleaded (advance it? retard it? how much??) Swapping engines or heads isn't an option, if it needs a new motor I'd rather put the work into a diesel conversion ... but only as a last resort. Any suggestions appreciated! Many thanks  Have a pic of it not overheating for inspiration   |
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barty
Posted a lot
Posts: 1,088
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Jan 24, 2012 14:46:41 GMT
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sounds like a head gasket, you can get it sniff checked at a garage to be sure, i used to have an old hunter with the ally head and i got through a few head gaskets while i owned it even though i had the head skimmed. Its an easy job though and you may not need to skim the head if you have the means to test it to make sure it aint warped. Again get it checked before you rip it apart in case its something else to do with the cooling
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Jan 24, 2012 15:14:49 GMT
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Could be HG - but unless it's showing other signs (water/vapour from exhaust, oily scum in radiator, mayo in sump despite a long run, etc.) I'd leave the head on for the moment.
Or a lack of cooling due to a 'lazy' thermastat that's not opening all the way or a partially blocked radiator.
Or poor engine efficiency due to incorrect ignition setup, low compression, incorrect valve clearances, lean mixture, etc.
I'd start by doing simple set-up things like the valve clearances, maybe do a compression test*, and then set up the ignition by ear and feel:
More advance will improve the low-end torque, but make it more likely to pink, will slightly restrict the top end, and make it easier to start. Too much advance will cause 'hunting' or 'surging' on the over-run, and make it difficult to turn over (firing on the compression stroke). Retarded ignition will lose low-end torque but allow more revs. Keep advancing the ignition a little at a time and then road-testing it until it either starts to pink or starts to surge on the over-run, then back it off a little until the pinking/surging stops.
Regular unleaded (95 RON) will probably need the ignition timing retarding: most engines of this era were designed with 98-RON 4 star in mind. If you set it up to the maximum possible advance as above and it's still reluctant to start (and a timing light shows the timing to be retarded from standard), it might be worth moving to super unleaded so you can run factory-spec timing. The improvement in fuel economy will probably mitigate the extra cost of the fuel.
If it still runs hot, check the thermostat and flush out the rad. It's worth checking that the radiator is clean on the outside as well, and that any OE-spec fan cowlings are in place if it still has the mechanical fan.
If it's still too hot, the radiator might be clogged with limescale type deposits - either have the radiator rodded out or re-cored.
Finally, is the rad cap OK? If it's the wrong pressure, or has become weak over time, the engine might be boiling prematurely.
*If the compression test shows low or uneven compressions after doing the valve clearances then there's something wrong with the engine - repairs will be a head-off job at least.
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ChasR
RR Helper
motivation
Posts: 10,309
Club RR Member Number: 170
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Jan 24, 2012 21:45:37 GMT
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Did you flush the cooling system out at the same time?
If it were me I would be tempted to go with a thorough flush until the water runs clean, and put in a new thermostat (a slightly open/stuck thermostat will cause strange cooling issues) with good mix of coolant in the water.
Regarding the pressurisation issue if you have any leaks (especially at the water pump (were all traces of the gasket removed?)) that can also cause over pressurising.
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Jan 24, 2012 22:03:12 GMT
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Many thanks for taking the time to give such a detailed list, my thoughts marked with "*" RR brownie points and good Karma are on their way to you ;D Could be HG - but unless it's showing other signs (water/vapour from exhaust, oily scum in radiator, mayo in sump despite a long run, etc.) I'd leave the head on for the moment.
* water in rad is clean, no mayo under oil filler, a little white smoke sometimes (may be normal - we had snow & subzero temps today  ), water sometimes low - but often months between needing a top-up 
Or a lack of cooling due to a 'lazy' thermastat that's not opening all the way or a partially blocked radiator.
* New thermostat fitted when I put it on the road about 2 years ago, seems fine.
Or poor engine efficiency due to incorrect ignition setup, low compression, incorrect valve clearances, lean mixture, etc.
* possibly any or all of above
I'd start by doing simple set-up things like the valve clearances, maybe do a compression test*, and then set up the ignition by ear and feel:
* valves done last year - compressions checked ok then, will retest and hope...
* timing not changed since I got it, will experiment and see
* Thanks for the advance / retard explanation, it's all appreciated !
If it still runs hot, check the thermostat and flush out the rad. It's worth checking that the radiator is clean on the outside as well, and that any OE-spec fan cowlings are in place if it still has the mechanical fan.
* rad outside is good, inside looks ok (maybe not 100% clean but matrix looks clear inside, water circulates well), no shrouds fitted (will check in manual to see if there should be, or maybe fit a leccy fan I've got in store),
If it's still too hot, the radiator might be clogged with limescale type deposits - either have the radiator rodded out or re-cored.
* good thinking - but it looks ok
Finally, is the rad cap OK? If it's the wrong pressure, or has become weak over time, the engine might be boiling prematurely.
* Not checked, will see if I can find a replacement to try!
If the compression test shows low or uneven compressions after doing the valve clearances then there's something wrong with the engine - repairs will be a head-off job at least.
*Afraid you're right - still hoping I can sort out a modern oil-burner to bolt in if it needs any work If compression test shows no problems I'll be looking at the timing / running lean / valve clearances options ... Hopefully it's something simple, would rather not strip the head if I can avoid it (snow here earlier today - and I work on the car outside in the field ) |
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Jan 24, 2012 23:21:07 GMT
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barty - my first thoughts were headgasket but it only seems to be a problem after a long slog (fully loaded up a long hill, etc), otherwise it will run for months without complaint. Good thinking about the sniff test, will get it checked out next time I'm in town. Chasr - car was running with no interior heater (bypassed) when I got it, the radiator was flushed and ran free and clear. New heater was flushed before it got installed. Only leaks at the pump were the seals on the old unit, new unit was fitted onto well cleaned block with new gaskets, no signs of leaks since. Water always circulates happily when you check the rad with cap off so thermostat is definitatly open a lot when motor is up to temp. Odd that temp is never a problem even with *very* little water in the system (touring Wales with a badly leaking waterpump etc ) Could it be wrong ignition advance at low revs & full throttle (ok at tickover and normal running but not when pulling hard under load ) |
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1725 shouldn't be dog slow, back in the day when they were just cheap cars i had a few of them should be able to keep up with a 1600 xflow escort, if it feels that underpowered it may have engine issues, first thing i'd look at would be the timing though, I never trust the marks on old stuff.
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Volvo back as my main squeeze, more boost and some interior goodies on the way.
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Dez
Club Retro Rides Member
And I won't sit down. And I won't shut up. And most of all I will not grow up.
Posts: 11,790
Club RR Member Number: 34
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Could it be wrong ignition advance at low revs & full throttle (ok at tickover and normal running but not when pulling hard under load ) it sounds to me like your coolant syatem is ok-ish (tbh they're never great in my opinion) but this is very likely. the lucas 25d has an utterly sh1te baseplate and advance mech so its quite common for it to not work properly. i had loads of problems on my commer with it, until i swapped it for the newer replacement- cant remember what it was but it was french made and i think speedy spares sell em? i think seth had problems with his one too recently? |
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Dez
Club Retro Rides Member
And I won't sit down. And I won't shut up. And most of all I will not grow up.
Posts: 11,790
Club RR Member Number: 34
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ive just remembered, its a ducellier one that fits, i don't know the part no. though.
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Seth
South East
MorrisOxford TriumphMirald HillmanMinx BorgwardIsabellaCombi
Posts: 15,543
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Are you checking the water level in between the 'overheating' episodes? Does it have an overflow bottle or just vent to an open tube? Could it be loosing a bit of water during regular running, enough to eventually cause the level to be a bit too low such that when it gets worked a bit harder it ends up steaming?
Dez, not had problems with mine - unless you count the fact that the badly corroded thermostat housing cap seems to have finally given up the ghost but I only discovered this when I opened the bonnet to give Kev's truck a jump start on Monday afternoon.... Its the Hunter rad in the Herald that we're not 100% sure about.
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Follow your dreams or you might as well be a vegetable. |
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Jan 25, 2012 10:35:56 GMT
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If the rad cap is the wrong presure or worn out then it maybe venting too early and alowing water to escape, also have you felt the rad to make sure there are no cold spots?
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bortaf
Posted a lot
Posts: 4,549
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Jan 25, 2012 11:52:23 GMT
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If teh rad cap is wrong or knackerd it will allow the water to boil at a lower temp next time it's warm check all over the rad for cool spots, that will show a blocked rad taht simple cant cope with the thermal load an uphill run creates?
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R.I.P photobucket
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Jan 25, 2012 15:13:37 GMT
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the lucas 25d has an utterly sh1te baseplate and advance mech so its quite common for it to not work properly. The 25D is ok as long as it's not worn out - though it's not as good as, say, a Bosch. The fact that it can wear rapidly if it's neglected doesn't help though. Putting a timing light on the engine and revving it up should give an indication of dizzy wear or stickyness. If the timing's moving about all over the place at a steady speed then something's worn. If it doesn't advance as the revs rise then something's siezed. |
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kevfromwales
Posted a lot
the conrod's REALLY out the block now!
Posts: 3,909
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Jan 25, 2012 16:32:59 GMT
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I don't recall there being a rad shroud on the hunter when it's original (to me) rad peed out water and I changed it sorry the old bus is giving you trouble pete  - kfw |
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Almost on the road: b11 sunny breadvan, e36 tds, 325i skidcar,
nearly there: ford f250 tathauler, suzuki alto, u11 bluey
not for a while: ford pop, 32 rails,
not in this lifetime: ruby, '29 hillman
''unfortanatly I'm quite old and scruffy and in need of some loving. my drive shaft needs a new boot....''
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rod
Posted a lot
Posts: 1,953
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Jan 25, 2012 19:22:33 GMT
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Ignition too far advanced? Does it 'pink'?
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Jan 25, 2012 22:05:42 GMT
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Just back from a quick fettling session (I prefer to do ignition work at dusk so I can see what I'm doing - but also any stray sparks around the coil & HT leads are easily spotted) Things I now know : * My timing light shows timing marks advance steadily thru' the rev range, vac pipe adds a few more degrees when I connect & remove it (so, A - advance is smooth, B - vac advance is doing something) * I advanced the timing about 5* (love the manual adjuster on the 25D), quick road test shows no change - still no pinking on hills or flat out. * The sparks between the HT leads on the OUTSIDE of the new distributor cap are very pretty at night ;D ... errm ... Time for some spray-on ignition sealer tomorrow * My nice, shiny, new (well, NOS) water pump has a bit of play in the bearings so I think the new pump is dying after just a few months  Are you checking the water level in between the 'overheating' episodes? Does it have an overflow bottle or just vent to an open tube? Could it be loosing a bit of water during regular running, enough to eventually cause the level to be a bit too low such that when it gets worked a bit harder it ends up steaming? Good point I've not really been checking, but if the new pump is leaking slightly (and I know the car runs ok with low water - from experience with the old knackered pump), it might be as simple as working it hard is too much when the water level is low. There's no overflow tank, any overflow from the rad is dumped on the road Another good point The shrouds around the rad - I checked and don't see any mention in the parts books or manuals apart from the top cover / finger guard that's already fitted so I don't think I there's any missing. Away now to re-read the manuals to see *what* the timing should be set at. The factory manual gives static settings, centrifugal advace is seperate, so you I need to work out (static + certifugal advance at fast tickover), then find those marks on the pulley. Fun My first guess is about 10* static + 10* centrifugal, so ballpark is 20* at tickover with vac pipe disconnected (my next guess might be a lot different) You learn something new every day I'm now thinking it's a mix of failing waterpump and suspect ignition timing. Many thanks for all the suggestions, hopefully it's getting there KFW - I'm amazed it's run happily for so long and without needing some kind of attention, it's well overdue some TLC for it's efforts ps - just noticed today the old water pump is wedged under the front seat, so I still have it if I need to put it back on |
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Last Edit: Jan 25, 2012 22:12:26 GMT by nomad
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Jan 25, 2012 22:45:13 GMT
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kevfromwales
Posted a lot
the conrod's REALLY out the block now!
Posts: 3,909
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Jan 25, 2012 22:54:45 GMT
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possibility that the alternator conversion isn't quite right, and is putting a funny strain on the water pump? - if it's been killed in a short period of time??
*I think it wasn't an OE alternator - but memory fades...
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Almost on the road: b11 sunny breadvan, e36 tds, 325i skidcar,
nearly there: ford f250 tathauler, suzuki alto, u11 bluey
not for a while: ford pop, 32 rails,
not in this lifetime: ruby, '29 hillman
''unfortanatly I'm quite old and scruffy and in need of some loving. my drive shaft needs a new boot....''
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djefk
Part of things
Posts: 844
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Jan 28, 2012 16:05:54 GMT
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My tuppence-
I had a 1500 Hunter de lux some time ago, great car but loved to overheat on motorway runs at high load - it took A LOT of messing around before I realised why. In your case your first task is obviously to eliminate the arcing on the dizzy cap. It sounds to me that either your HT leads have had it or you've been sold a duff cap. Anyways....
1) Both 1500 and 1725cc engines are very sensitive to correct ign timing and prone to pinking, though you say yours doesn't pink you also say that youre guessing the correct timing setting - You do need the exact figure so beg, borrow or buy a Haynes manual as a priority and try this first - If it still overheats in the same circumstances afterwards then you can confidently discount this if you are 100% sure you're listening hard and it isn't pinking up hills at high load (it wont be obvious so best to check at 30-40mph max in overdrive top when there won't be much other noise to disguise it). It will definitely need the timing retarded from the standard setting by at least a couple of degrees to run cleanly on 95 RON unleaded btw.
2) I found the needle in my carb to be worn so that at lower revs / load the mixture was correct, however at high loads it was running lean - I would definitely try replacing the needle and jet in your carb (along with a new rubber diaphragm and gaskets while you're there - its so easy and cheap to rebuild Stromberg carbs even if you've never touched a carb at all before)
3) If no change and the cooling system itself is known to be good then as has been said, bite the bullet and take the head off. It's so quick & easy and allows you to check for engine wear (these engines go on running sweetly even when the bores, rings and bearings are very worn - Does yours breathe out of the rocker cover when running?). Mine was unbelievably bad yet still started and drove fine (albeit was pretty slow!).
I cleaned the head of all the oily swarf that had built up in the oil drain passageways to the point where they were almost blocked(!) and put it back on with a new top end gasket set as a temporary measure while I decided what to do longer term, I noticed it no longer overheated (although it did get warmer than usuaal still) and the oil light no longer flickered at idle after coming off the motorway (does yours do this out of interest?)
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Last Edit: Jan 28, 2012 16:34:18 GMT by djefk
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Thanks for all the suggestions folk - have been working throught things (and having broadband problems) hence the slow reply. Apologies My tuppence- 1) 2) 3) .... the oil light no longer flickered at idle after coming off the motorway (does yours do this out of interest?) Ignition - took the distrib cap off to coat it with ignition sealer (spray-on waterproof / rubber stuff ) Think I've found the cause for the glow-in-the-dark lightshow, the neat silicon HT leads looked fine but one had a clean break through the insulation - not normally visible as it was unfer the dust boot.  Just back from a 40 mile drive in sub-zero temperatures, car is overheating badly and had to stop 3 times to fill the rad (so it's used / lost about 4 GALLONS from the cooling system in less than an hour No obvious leaks so I'm now sure it's internal. Would normally be head-off time by now - but - have just bought a known good motor & gearbox for scrap money ;D Just trying now to arrange collection then can swap if with the dying motor in the car Replies to above 1) - have put ignition back to where it was (I have factory manuals but they give static timing, you then add x degrees per 1000 rpm, shame they don't give timing info at tickover rpm  2) Good point about the carb, it keeps working so I've not opened it up to check inside. 3) "Known good cooling system" - I think we can say that's NOT what is fitted Hoping I can get the new motor and fit it this week then see what happens. Good info about the swarf, will check head if I take it apart.. Yep - oil light flickers sometimes, when waiting at lights with a hot engine is favorite. Thanks for all the ideas & suggestions, will update the build log as & when I find out more retrorides.proboards.com/index.cgi?board=readersrides&action=display&thread=88892&page=1Edit to fix link |
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Last Edit: Feb 5, 2012 15:23:15 GMT by nomad
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), water sometimes low - but often months between needing a top-up 
