Overheating Roadster

[J_Phillips]

Hello folks. I've a Roadster which I built in 1984. I've been with MOC for years, but this is my first post. Hope to meet you all one day! My car was my main transport from 1984 till 1997 when the arrival of my son meant a 2-seater would be tricky for family use. Managed to keep it going off and on till 2006, when the car entered a (garaged) 14 year hibernation. It's been worked on and is legal again and back on the road now!! It's Marina 1800TC, with stock Viva type radiator, with electric fan. During it's re-commissioning, I've had the radiator re-cored, and a new electric fan fitted (to the front if the rad), the system is flushed and watertight. It's just been converted to unleaded and the head skimmed a bit, so compression is up a tad. There is, as usual (as there was back in the day when I ran the car for the first few years), an enormous amount of heat. Even with the heater on full blast (just what you want on a hot day) the needle is touching red and the engine runs ragged. I'm going to embark on a radical overheating solution quest. Can I ask for advice please? I see a number of posts on this topic but some are 10 years + old, and a more recent one (Steve, 2014) has a document which is no longer available. I'm thinking about glycerol coolant, an oil cooler, a secondary radiator under the wings maybe. It's the #1 reason why the car is hard to enjoy, feeling roasted the whole time and on the verge of breaking down. Radical ideas or suggestions of great interest please! Best wishes all, James Phillips.

[Gareth]

Re: Overheating Roadster

Hi James, I've had similar problems on my Roadster. Make sure all the air going through the front grill goes through the radiator and not around it. You've probably got no cowling between the grill and radiator. Also, if you've got an original metal fan on the water pump, make sure it's the right way round!!! Don't ask me how I know...
I also fitted a 3" blower from a chandlers, and some flexible ducting pointing under the carb to stop the petrol evaporating in traffic, it works.
If you're anywhere near Chester, you're very welcome to pop round! All the best, Gareth.

[listerjp2]

Re: Overheating Roadster

Does your car have the shark gills on the side of the bonnet panels. If not that could help. What ever you do don't take the original fan blade off as that assists the under bonnet temperature. When I first went to Let mans Classic (always bloody hot) I over heated because I was trying to rely on only the electric fan. The next time I went I put the original fan back on along with the electric fan and no problems.

A tip from a classic car mechanic.

Good luck.

Adrian

Hi James, I've had similar problems on my Roadster. Make sure all the air going through the front grill goes through the radiator and not around it. You've probably got no cowling between the grill and radiator. Also, if you've got an original metal fan on the water pump, make sure it's the right way round!!! Don't ask me how I know...
I also fitted a 3" blower from a chandlers, and some flexible ducting pointing under the carb to stop the petrol evaporating in traffic, it works.
If you're anywhere near Chester, you're very welcome to pop round! All the best, Gareth.

[dcunn]

Re: Overheating Roadster

James, welcome onto the Forum

I'll let those with more knowledge than me answer your query, suffice it to say
that it's not an unknown problem, and there are many solutions.

From my perspective as archivist I would like to know which car you have, and
if it is chassis 2683 reg Q218 etc - - pretty please can I have some pics ?

Please send to my email as in Pitstop

Rgds Dave Cunnington MOC archivist

[J_Phillips]

Re: Overheating Roadster

Gareth, thank you for your reply, these are great ideas. There is no cowling between the grill and the radiator - I'll get that done. I see there's a reply from Adrian here too about the original metal fan. I don't have that at all any more, let alone the wrong way round. Not sure when that was removed - either I did it in a moment of madness or an enthusiastic fixer has done so, I will get that put back on. Could you add some detail re the '3" blower from a chandlers' please? What's that and where is is added? It's blowing some fresh air on the carburetors? I'm in Twickenham normally, so not too near Chester, but will get in touch if I am up your way, likewise let me know if you're in Twickenham! Again, any detail re the 3" blower etc would be gratefully received. BW James

[J_Phillips]

Re: Overheating Roadster

Adrian, really good of you to reply with these ideas so quickly, thank you. Yes, I have the shark gills! And you have probably hit on something re the original fan blade, long since gone and as I said to Gareth who has also replied, I don't know/can't recall when this went but I would not be surprised if it did not coincide with a serious bout of overheating back some time ago! I will get this refitted asap, thank you for this.

I've not been to Le Mans, sounds like a fab idea, but in 1986, I took the Marlin to visit the 60th Mille Miglia, that was an awesome drive and holiday, 2 weeks 3000 miles, lots of hand waving.

Best wishes James

[J_Phillips]

Re: Overheating Roadster

Dave, I'm chassis 2402, reg Q425JWU. Could you give me a little time please and I'll get you the photos, I'm just re-trimming and the moment and better that you have these after it's spruced up.
I mentioned to Geoff G that I would be offering up a recommissioning journal/article with photos in due course, also pending the re-trimming, so that's in the pipeline too.

Best wishes James

[listerjp2]

Re: Overheating Roadster

Albeit that Le Man's Classic has been pushed to next year, there will be six of us going (two Marlins), it's a brill gig.

Mille Miglia sounds brill as well.

I have the A Series engine but have the 7 blade fan from the MGB which works well.

Twickenham is not that far from me and maybe we could meet up sometime.

Good luck with the rebuild.

Adrian

Adrian, really good of you to reply with these ideas so quickly, thank you. Yes, I have the shark gills! And you have probably hit on something re the original fan blade, long since gone and as I said to Gareth who has also replied, I don't know/can't recall when this went but I would not be surprised if it did not coincide with a serious bout of overheating back some time ago! I will get this refitted asap, thank you for this.

I've not been to Le Mans, sounds like a fab idea, but in 1986, I took the Marlin to visit the 60th Mille Miglia, that was an awesome drive and holiday, 2 weeks 3000 miles, lots of hand waving.

Best wishes James

[dcunn]

Re: Overheating Roadster

James, thanks for the reply.......... I obviously guessed the wrong Phillips, sorry.

Here's the only pic we have of your car, at the Newark Show in 1984

I look forward receiving your pics, both old and new, whenever you get time

[marlinmick]

Re: Overheating Roadster

Hi All, I am also refurbishing my Roadster that I built in the mid eighties and I was plagued with overheating problems and a major reason why it ended laid up for years. For this refurb I have had a Big Block Aluminium Radiator made for it by Custom Built Rads of Nottingham it is thicker and longer than the original (Standard Viva Rad) and has the largest fan that will fit into the very confined space of the nose cone. I have also ducted the inside of the nose cone to direct all the air through the core. My original engine driven fan exploded years ago during a heavy braking application as the fan blades contacted the steering rack fasteners. I did replace it with one with trimmed down fan blades but it made no difference to the overheating problems so fitted a thermostatically, controlled fan instead which helped but I still had to have the heater going full blast as well, incidentally my overheating problems got worse after I had the engine re-bored and new pistons and rings fitted, it got so bad that I had to stall the engine to get it to stop. So hopefully this new rad should cure my overheating problems, if not its been a very costly waste of time. Hoping to get it running this month to do heating/cooling trials some trials I just rebuilding the gearbox it the moment and doing some kitchen remodelling (in the house of course) so cant wait to get back on it.Marlin Nose Cone Ducting.jpg

[listerjp2]

Re: Overheating Roadster

Looks a nice job.

I also noticed, like me, you put a couple of slits in the nose cone to drain water that tends to sit there.

Adrian

Hi All, I am also refurbishing my Roadster that I built in the mid eighties and I was plagued with overheating problems and a major reason why it ended laid up for years. For this refurb I have had a Big Block Aluminium Radiator made for it by Custom Built Rads of Nottingham it is thicker and longer than the original (Standard Viva Rad) and has the largest fan that will fit into the very confined space of the nose cone. I have also ducted the inside of the nose cone to direct all the air through the core. My original engine driven fan exploded years ago during a heavy braking application as the fan blades contacted the steering rack fasteners. I did replace it with one with trimmed down fan blades but it made no difference to the overheating problems so fitted a thermostatically, controlled fan instead which helped but I still had to have the heater going full blast as well, incidentally my overheating problems got worse after I had the engine re-bored and new pistons and rings fitted, it got so bad that I had to stall the engine to get it to stop. So hopefully this new rad should cure my overheating problems, if not its been a very costly waste of time. Hoping to get it running this month to do heating/cooling trials some trials I just rebuilding the gearbox it the moment and doing some kitchen remodelling (in the house of course) so cant wait to get back on it.[ATTACH=CONFIG]11755[/ATTACH]

[lil_red_roadster]

Re: Overheating Roadster

I do like that rad..!


Don't forget to check timing & mixtures...overly lean mixtures or excessively retarded ignition will generate additional heat and cause rough running. Also check for leaks in the induction system and vacuum line. Waxstat carb jets will not help either, so if you have those replace with standard jets (they lean-off as it gets hot). What needles are fitted to the carbs...stock TC needles will be too lean when running pancake filters.


I'm running a recently rebuilt TC with 3-core Viva rad, expansion tank & electric fan and I've not experienced any issues with overheating. Everything was refurbed, including the carbs & an Aldon distributor fitted and I'm really pleased with how well-behaved it is compared to my original setup.

[meverett]

Re: Overheating Roadster

Hi James,
I take it that your electric fan is blowing air through the radiator from the outside and not sucking hot air through from the engine bay.
I could have easily made that mistake when fitting mine and testing the fan (also on the outside between the rad and grille).
Also when it overheats do you hear the electric fan kick in?
My roadster is still mid rebuild so I too may be plagued with overheating, I will find out one day.
Cheers, Martin.

[J_Phillips]

Re: Overheating Roadster

Hello Marlin Mick, thank you very much for this post, I really do have to pay attention to the "ramjet" as it where, for the airflow to the radiator. I have no cowling at the moment, so this is likely to be helpful. I see what you've done there with the aluminium (I assume) or tin (maybe) plate. I know what you mean by "so hot it keeps running", I have overrun all the time on switch off. I also have power loss when the engine gets too hot, I think something starts to go horribly wrong with evaporating fuel, I'm really not sure. Good luck with the gearbox and kitchen. I need to attend to my gearbox, I have some 1973 cogs in there which I doubt have ever seen the light of day, and 1st gear synchromesh is not of this world any more, I have to go to 2nd gear slot first and then to 1st and then engage, if I don't want to crunch. Good luck with your projects and getting the car on the road again. I note your rain water drain hols in the front scuttle/damn, good idea... Best wishes James

[Gareth]

Re: Overheating Roadster

Gareth, thank you for your reply, these are great ideas. There is no cowling between the grill and the radiator - I'll get that done. I see there's a reply from Adrian here too about the original metal fan. I don't have that at all any more, let alone the wrong way round. Not sure when that was removed - either I did it in a moment of madness or an enthusiastic fixer has done so, I will get that put back on. Could you add some detail re the '3" blower from a chandlers' please? What's that and where is is added? It's blowing some fresh air on the carburetors? I'm in Twickenham normally, so not too near Chester, but will get in touch if I am up your way, likewise let me know if you're in Twickenham! Again, any detail re the 3" blower etc would be gratefully received. BW James

Hi James, Look on eBay for the blower. I fitted it behind the front number plate and got a 1 l8tr length of flexible ducting and just cable tied it to under the carb. I switch it on if needed,
The blower is normally used to vent inboard motors on boats to purge petrol fumes before start up.
Gareth