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Holbay120
United Kingdom
177 Posts |
 Posted - 24 Jun 2010 : 15:27:54
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Hi, I wonder if anyone else has had any problems or thought’s with fuel, fuel evaporation and whilst not exactly overheating getting very hot. Regarding fuel leaded four star is just about impossible to get so I’ve been using Tesco’s super (99 ron) and adding millers VSP plus additive. When it comes to fuel to quote Mungo Jerry “ some say dat and some say dis some say no and some say yis”, from this months Practical Classics :- valve seat inserts were fitted to all engines but officially you will need an additive or head conversion to prevent recession but engines fitted with an alloy head are less likely to suffer from this problem, so that’s very clear then er? also from the same magazine - with regard to fuel evaporation :~engines run hotter on today’s unleaded fuel and performance engines can make them (the carburettors) even hotter still. Hmmm well, when I’ve using my Rapier it is a so & so to start when it’s hot ( though fine when cold) and on a warm day it does run a bit warm- I have flushed the cooling system out changed the thermostat, changed the temperature gauge sender but it’s made no difference, I also bought a new water pump but the one on the car seems OK, so it’s wait until it’s a bit cooler outside or go with the heater on full blast ( which makes she who must be obeyed very happy!). I would imagine the 1725 fitted with twin SU’s would be considered a performance engine compared to the standard 1725 never mind the H120 so has anyone else any thoughts, opinions or ideas about this? I had thought about an electric fan (Kenlow etc) but where would you fit it? There is also the option of insulating the manifold but it’s expensive and I believe a bit hit and miss and finally cutting louvres in the bonnet but that’s a bit drastic and would ruin the car. I have heard of a larger radiator being made for some cars ie a Stag to cure these issues but not for a rootes car. So I wonder what you most knowlegable chaps out there in rapierland would have to say and any ideas some may have- (I await with baited breath!) Regards Etc
David McKenna |
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1922
United Kingdom
549 Posts |
Posted - 24 Jun 2010 : 17:04:59
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I got a radiator built for my 1840 Holbay with an extra (third) row of cooling tubes by Serck Marston (but still using the same top and bottom tanks). To be honest I don't think the extra row was necessary and a good clean radiator is good enough - but it wasn't much more money for the extra layer.
If you are finding that the temperature gauge still over half way even after flushing the system you may need a the radiator recored, or perhaps the viscous coupling on the fan isn't doing it's job (if yours has one).
I've been off the road since LRP disappeared, so I've never run on unleaded. So my advice is a bit out of date and apologies in advance if I state the b***dy obvious 
Back then (10+ years) I did find that getting stuck in traffic on a hot day would lead to a nasty flat spot between 1200 and 2000 rpm that made the car difficult to drive but it never actually stopped. I found that a couple of seconds of wide open throttle would cool the carbs down again and all would be well again.
This is because the carbs do get a lot of heat from the tubular exhaust system - I think this is a much bigger factor than the engine temperature. If this is your problem I think you would see problems in traffic too (on a hot day) not just starting problems.
Have you checked it's not running too rich? Could be the cold start levers are not returning fully or just a mucky air filter.
My 1840 was very fussy about the starting procedure - do it right and it will start in less than a turn, do it wrong and it will take you half an hour!
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JPSH120
United Kingdom
1184 Posts |
Posted - 24 Jun 2010 : 19:35:59
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Heat soak can be a problem with the manifold being so close to the carbs, I think wrapping the manifold is the best solution. The carbs need regular tune ups to make sure everything runs nicely. It is very easy to flood the engine with the webers, really the carbs are a bit OTT for the engine.
I was planning on having my CH head converted to run on unleaded but I've had several discussions with various people and as per the practical classics article the head already has hardened valve seats so can run on unleaded. A friend of mine has used unleaded in his series 5 rapier for years with no problem. Having said that the H120 was meant to run on 5 star so the higher octance fuels (V-Power, BP Ultimate etc) are better for it. There is a local garage near me that still sells 4 star but it's so expensive I switched to UL before the car came off the road.
And finally regarding the overheating, it might be worth checking your thermostat. It should have a ball valve in it and although "std" thermostats are allegedly OK they don't perform as the original does.
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Holbay120
United Kingdom
177 Posts |
Posted - 24 Jun 2010 : 22:15:26
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Hello Derek and Jason thanks for your replies and thoughts as these are the things I wondered about what others thought, as I understand it there is not too much to worry about, on a normal day say up to 60f everything is OK but on a hotter day the cooling system is struggling to cope with the extra heat caused by modern fuel plus the heat of the day, ie:- it can cope with one or the other but not both. As I said earlier it’s not exactly overheating or boiling over etc - given that 10 o’clock is cold 12 o’clock is normal and 2 o’clock is hot, the temp gauge gets to about 12:30 ish and by putting the heater on and/or speeding up the engine it comes back down to normal again so I’m thinking that the fuel is the problem, however I didn’t know the H120 had a different thermostat and I’m not sure how you can test a vicous coupling fan- I have noticed I can turn the fan without turning over the engine but it spins like billyho when the engine is running it‘s a yellow plastic type and all the blades are OK, When I get home I’m going to try running without a thermostat and see if that helps. I’ve had the carbs checked by a local webber specialist and they are fine, however his opinion is that because of the extra heat coming from the manifold the fuel in the carbs is evaporating and as things cool down colder fuel will seep through and the way the car behaves seems to back this up. So it appears to be a viscous circle because of the way modern fuel burns the exhaust gets hotter which in turn evaporates the fuel in the carbs when the car is stopped, Regarding leaded fuel I too have heard of people who run on unleaded for years without a problem in this case a hunter shape Sceptre and I know Glen thinks along these lines too so I have been erring on the safe side and only using VSP every third or fourth fill and think that due to lead memory this should be fine, VSP also increases the fuel 2 points which added to 99 ron gives 101 (obviously) and she does like that, accelerating like a rocket (up to the national speed limit of course! ahem). So that was my main question or talking point, what others had experienced or thought about modern fuels in older cars as in cases like this, others opinions can often throw light on thing’s , maybe there will be some more post’s on this as it’s an interesting subject and must affect other people’s cars. Best Regards etc
David McKenna |
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JPSH120
United Kingdom
1184 Posts |
Posted - 25 Jun 2010 : 19:13:43
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Being older mine has the fixed fan set up but IIRC the viscous fan should run at low revs and then stop as engine speed increase as the radiator will then be getting air anyway. You should be able to test it by opening the throttle and seeing if the fan stops.
I'm not too sure whether UL fuel would cause the manifold to get hotter than normal, it gets bloody hot anyway!
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1922
United Kingdom
549 Posts |
Posted - 26 Jun 2010 : 11:13:01
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I think that if putting on the heater lowers the engine temperature this is a sure sign that you are not getting enough cooling. If eveything is working properly turning on the heater will not change the engine temp, as the thermostat would close up slightly to compensate.
This might be extra heat from unleaded, but the symptoms could be a blocked radiator.
I remember a trip down the A11 on a hot day when, too keep the needle out of the red, I had the choice of sticking to 50mph or I could do 70mph with the heater on full blast and all the windows open (this was cured by a rebuilt radiator - it was furred up inside like an old kettle). If the temperature climbs at high road speed and drops when the heater is on or when you slow down the prime suspect is the radiator. If it's choked up with scale then flushing won't work (I've tried it and kettle descaler too). You should be able to get the radiator rebuilt with a new core by any radiator specialist - and you could get it changed to 3 rows of tubes at the same time if you want some extra margin.
If the temparature is high in slow traffic only, it could be the fan. The coupling limits to fan speed to about 3500rpm (and releases 3 bhp) - you should be able to turn the fan freely by hand and it should stop quickly when you stop pushing it. Give it a good shove, if it stops in a half a turn or so it's ok, if it keeps spinning or wobbles then it's time for a new coupling.
As Jason said, the thermostat should have a little pin and ball valve in it, this helps stop an airlock forming in the thermostat housing. All the Arrow cars use the same 82-83C thermostat and all should have the 'jiggle pin' - which should be at the highest point when fitted.
As for the hot starting; it does sound like heat soak from the exhaust. I read somewhere that unleaded is more volatile than old fashioned 4 star and is more prone to evaporating. Certainly the exhaust gets d**n hot - I had to make a heat shield for the steering idler because the heat from the exhaust kept melting all the grease out of it - so I'm wondering if there's any chance of making a heat shield from a thin piece of stainless steel that could go between the carbs and exhaust.
Final thought - my second Rapier (1725 with Weber carbs) spent a few years living in Europe with the previous owner where it must have been run on unleaded. I know he drove a lot of miles on the Autobahn from the UK to Hamburg, Cologne and even to Malmo. Much of the time well above 70mph. I don't think he had this trouble - I'll send him an email to ask. |
Edited by - 1922 on 26 Jun 2010 15:32:33 |
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argonaut
Hungary
39 Posts |
Posted - 26 Jun 2010 : 11:38:00
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Well as the previous owner of 1922's car I can confirm that I ran it for a few years and drove it all over the continent - Sweden to Germany and the UK and all points in between, I used to tank unleaded most of the time but every 4 or 5 tankfulls I would fill up with leaded petrol. I never had any problems with the engine whatsoever (the engine is a H120 wannabee in that it doesn't have the tubular pushrods, the head isn't stamped but it has Weber DCOE 40's fitted and runs very well).
I think that there's a lot of myths surrounding the use of unleaded causing higher temperatures - it may run slightly hotter but I don't believe it would create that much of a problem sufficient to cause overheating, fuel vapour lock or similar problems. As already suggested, I think there's something not right with your cooling system. The fastback cooling arrangements is a tried and tested system and works quite well, you should not be experiencing overheating problems at all. I would check that the radiator is clean and not silted up - disconnect top and bottom hoses and place a garden hose pip in the top of the rad and let water run through it - CAUTION though, don't have pressure on the water, you want the water to gently run through the rad or you can damage the core. At the sime time, you'd be amazed at how much crud can build up in the water jacket of the block, you might want to flush that too. Also, check the thermostat's working properly - if you're really worried about overheating you can simply leave the stat out but then the heater will be naff in the winter. Ref checking the viscous coupling, when the engine is warm there should still be some resistance on the fan, if it will spin freely when the engine is hot (switched off, try to spin it by hand) then it's possible that the viscous coupling isn't doing what it's supposed to do - some designs of these can be repaired, there's a bi-metallic strip* fixed on front of the coupler which when expanded allows a pin to move in and out - that in turn controls oil flow in the chambers of the coupler. Check that the pin moves freely. I can't remember the exact layout of the holset unit but have a look at it.
Hope that helps and sorry if I've repeated stuff here,
Cheers
* Apparently not on the Holset type, I don't know ecatly how these ones work, sorry. |
Edited by - argonaut on 26 Jun 2010 16:32:40 |
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Holbay120
United Kingdom
177 Posts |
Posted - 27 Jun 2010 : 13:21:10
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Thanks Guys, I do appreciate your advice and there is no need at all to apologise for anything your not sure about, I’m very grateful for your help. As I said I did flush the radiator out last year as per Haynes manual, all that came out was clean water and that improved things for a while, though I do appreciate there may be a lot of scale in there so I’ll take it in at the same time as the petrol tank as that’s shedding it’s interior coating and clogging up the fuel line and pump (groan).The thermostat was a new one off Glen and it does have the little ball and “T” piece at the top so I think that’s OK, the fan is certainly turning when it’s ticking over and it won’t turn much if I try to spin it so I think that’s OK. Daft question if I asked for an extra core fitted will the radiator fit back in or will the mounting brackets need altering and will I need different hoses made ?,It’s going to be an expensive month because I’ve still to get the camber sorted ( I’ve just about bought a new everything for that!) if and it’s a big if I can find a place to sort it out- it’s too big a job for me in my little garage - ah! The joys of motoring, so depending on the time available I may just have to take the thermostat out for now and get the fuel tank & radiator sorted at the end of September when she hibernates for six months. It was very interesting to read people’s views on fuel it’s certainly a can of worms worth opening! I’ve just found out that there is a bigger radiator for Interceptors available as they get hot with modern fuel so maybe there is something in it, Regards etc
David McKenna |
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1922
United Kingdom
549 Posts |
Posted - 28 Jun 2010 : 14:30:15
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When I had my rad changed from 2 cores to 3 cores there was no change to the tanks, hoses or brackets. It bolted straight back in. The only problem is that because the radiator core is thicker it is then rather close to the centre bolt in the fan.
From memory I think I filed down the bolt head a little and bent the brackets a wee bit to get a bit more clearance.
When I had trouble with the paint flaking in the petrol tank I fitted a bit of gauze to the outlet. I used the intake filter from a moped petrol tap (cut off with scissors!) and just shoved it in the end of the petrol pipe (where it screws into the petrol tank). It's a bit of bodge but it worked. |
Edited by - 1922 on 28 Jun 2010 14:35:15 |
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argonaut
Hungary
39 Posts |
Posted - 28 Jun 2010 : 21:13:31
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| My old Rapier had problems with rust flakes/crud in the fuel lines - in fact that caused one of only two raod side breakdowns (the other was a bust throttle cable). The German ADAC (=AA) man came along and blew back down the fuel line from the fuel pump with compressed air - that cleared the blockage and it never happened again - I did make sure that I didn't run the tank too low though. |
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Holbay120
United Kingdom
177 Posts |
Posted - 29 Jun 2010 : 08:51:57
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Yeah I blew it back last year and cleaned out the fuel pump filter etc but it was causing fuel starvation again last month so I did it again. I had the same problem in the 70's and the only permanent fix was have the tank top took off and the inside cleaned out, it gave me no more troulble after that (well the fuel system didn't!) Regards
David McKenna |
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argonaut
Hungary
39 Posts |
Posted - 29 Jun 2010 : 15:02:56
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Well if you do need to properly clean the tank at least it's easy to get to. You can get decent internal access if you remove the fuel tank sender unit too.
Cheers |
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JPSH120
United Kingdom
1184 Posts |
Posted - 02 Jul 2010 : 12:06:12
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Hi David,
Further to the recent posts regarding your overheating concerns I was re-reading a recent article in practical classics last night on buying any of the arrows saloon range and it reminded me to mention to you it may be worth checking the cylinder head. If you're not sure about the anti-freeze content in the cooling system, you may have a problem with internal corrosion in the head which could lead to some of the symptoms you mention.
When I removed my thermostat housing I was shocked at the state of the waterways in the head but it did at least explain why my heater matrix was full of gunge and why the heater stopped working long ago!!
The same article also states that the head has high quality inserts making unleaded fuel OK to use although an octane booster is suggested for smoother running.
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Holbay120
United Kingdom
177 Posts |
Posted - 02 Jul 2010 : 15:04:46
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CYLINDER HEAD!,are you trying to frighten me to absolute death? a bloke can only take so much you know!, actually I did think about the head gasket but it's been checked out and it's OK. When I bought the car Kim did tell me about this getting warm on very hot days so it's nothing new for this car - never the less I'm going to take the radiator out and have it overhauled, flush the system, change the thermostat again and have the fan checked out by a garage and if that does'nt work ??.It's good to hear (and see)
coming back to life, we'll have to have a race on a cold day!! Regards Etc PS there are some black holbay stripes just come up on
e-bay.
David McKenna |
Edited by - Holbay120 on 02 Jul 2010 15:16:36 |
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JPSH120
United Kingdom
1184 Posts |
Posted - 02 Jul 2010 : 18:18:12
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Sorry don't meant to give you any heart flutters, but for the sake of taking the thermostat housing off and just checking all looks OK inside its worth it.
I think mine probably had zero anti-freeze in it so the ally/steel combination with nothing but H20 swilling round resulted in some pretty shocking head corrosion!
Thanks for the tip off re stripes, on holiday tho from next Tues so not here to bid and pay for them.
They can be got tho and as I want high gloss stripes I may have to have some made anyway.
Not sure about a race, maybe some group photo's would be kinder!!
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Holbay120
United Kingdom
177 Posts |
Posted - 02 Jul 2010 : 20:49:56
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Hello Jason, Yeah! a bloke could be killed to death giving him shock's like that, as I said when I get home I'm going to take the rad'to master radiators and flush the rest out again.Since I've owned the car I've always had anti-corrosive anti-freeze in it (I use Holts it doesn't seem to seek leaks out), of course I'm only joking about racing but if we ever did manage a meet I would naturally expect BJU to look like this:~
Pity about ths stripes, Hope You have a nice holiday Regards etc
David McKenna |
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Fuel, Evaporation and Overheating
