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engine side valances-yes or no ?


alarmman49
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Hi everybody,

 

I'm coming to the end of a 2 year "renovation, tidy up, sort out, put right" of my previously abused and very unhappy 1981 1500 Spitfire. The car is now a really usable classic with various sensible upgrades ( better brakes, etc etc.) and I am really happy with it. :)

 

Question 1 : should I re-instate the missing engine valances ?? I have read various articles suggesting leaving them off, others say they improve engine cooling as well as the obvious keeping the engine a little cleaner from muck thrown up. I do have the radiator ones fitted.

 

Question 2: I am running with K & N filters and have read that all engines prefer "cold air" supply through the carbs hence the hoses on the original Triumph air filter, should I run some form of hose to supply the K & N's with cooler air ??I am trying to ensure the carbs run at their optimum re performance and fuel economy.

 

Any comments would be welcome, thanks, Tony.

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Question 1: Not sure if it's better or worse but I never got around to reinstalling them on my Spit after it's (body) restoration and can't say I've seen much different in road dirt getting on the engine/temperatures vs. driving with them on before restoration.

 

Question 2: Cold air's more dense so has more O2 per-litre than warm air.  More O2 means more bang, means more power.  In reality there's not much difference on the move but it won't be so keen on sitting in traffic queues/pulling for the first 30s after pulling away from being sat in traffic - and even then heat soak in to the carbs/fuel vaporization will be part of that and an issue with/without a cold air feed.  If you want every last hp, then a cold air feed is the way to go but is it worth the time, effort and money...

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I thought they were supposed to make engine cooling worse.

I've got them fitted on my Mk3 and it does run quite hot, particularly in traffic (std mech fan). I've put this down to the hot air not being able to exit the engine bay. Don't forget early GT6s had louvres  in the front wings to help with air flow.

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I'm a great believer in keeping it the way Triumph designed it with the exception of reasonable upgrades like electronic ignition, braking improvements, inertia reel, comfy seats etc.

 

They put in engine valences for a reason, they route air flow over the gearbox and under the car. They also keep road dirt off the engine. What's not to like? :lol:

 

similarly the air filters, if I bought a car with K & Ns, they would be the first thing to go! Followed by the electric fan and any suspension lowering gubbins!

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If I bought a car with K & Ns, they would be the first thing to go! Followed by the electric fan and any suspension lowering gubbins!

 

I always reckoned that with things as tight as they were in pricing and costs, if the valences weren’t required, they’d have been removed by Triumph. Consequently there had to be a reason for their continuing fitment - probably keeping dirt off the engine and improving airflow. 

As for K&Ns… everyone upgrades when they first buy, then after a few years they ditch them and go back to standard… my first Spitty got oil cooler and thermostat, electric fan, uprated springs, K&N filters, additional dials.. then they all came out again when I realised they were for show - because everyone else was doing it - and didn’t make one hoot of difference to the car’s performance or longevity.

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I can only comment on the Mk3, but the parts book lists the valances as:

 

   'Fitted to all vehicles up to Comm. No. FD22863 L.H.S. and FD16350 R.H.S. Fitted to Special Order only under kit no 569563 from Comm. No. FD22864 and FD16351.'   

 

These were the two different ones i.e. a left and a right.

 

Then 1 under a different part number for Engine Bay R.H. only  for USA from FDU75001

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You are so right Colin - experience teaches that Triumph actually knew what they were doing (even if it was down to a price..) and that every mod brings in its wake some knock-on effect or problem you had not bargained for, which then needs another mod.

Only in the latter days of the marque were they guilty of some really poor ideas - Waxstat jets, cardboard washers in diffs, dodgy spit downpipe gaskets all come to mind. Mind you, the lack of fuses on most of our cars does count as a shocking bit of penny pinching, even if the threat of instant immolation does keep us alert!

 

Steve-C

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wax stats and temp compensators were a requirement to aid emmissions in the 70/80s , same a s thermac air filter controls  it was needs must rather than triumph wanted, applied to most manufactures of the day. there were lots of bright idea's  used to lower Co and HC content , 

I ran an emission dept with gas bags , gas fridges , volume metering and gas analysers in the 70s and 80s, for pertol engined trucks and diesel smoke 

 

and we were all caught up with tamper proofing , and wild idea's to get the levels down,  the spin off was the cost of fuel took over and to get better economy the ideas grew and levels dropped to the fresh air out the exhaust like todays vehicles and mpg unheard of when our cars were tops.

 

the lack of fused circuits was also the norm for the designs of the day , not skimped just normal  for the trade 

 

Pete

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Plenty of evidence that K+N's offer improvements over std air filters, BUT and it is a very BIG but, the vast majority are a waste of time and probably make things worse.

If any modifications, like K+N's, manifold or whatever, it needs to be thought through and the knock-on effects sorted. If K+N's are fitted, they really ought to have stub stacks fitted inside to hugely improve the airflow (probably far more than just the filters). And of course, if you have more air, you need more fuel. So a change of needle and/or piston spring. All best achieved on a rolling road, although there are plenty of long-term recommendations for "standard" modifications.

 

Cold air feed is also very worthwhile, along with good heat shields. I have seen k+n's fitted inside airboxes. In fact, on my vitesse, I had a modified std airbox with the K+N elements inside. No bling, but a case of function over form. Another option would be to use the std airbox empty, and connect the tubes to a remote filter placed in front/to one side of the radiator.

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Plenty of evidence that K+N's offer improvements over std air filters, BUT and it is a very BIG but, the vast majority are a waste of time and probably make things worse.

If any modifications, like K+N's, manifold or whatever, it needs to be thought through and the knock-on effects sorted. If K+N's are fitted, they really ought to have stub stacks fitted inside to hugely improve the airflow (probably far more than just the filters). And of course, if you have more air, you need more fuel. So a change of needle and/or piston spring. All best achieved on a rolling road, although there are plenty of long-term recommendations for "standard" modifications.

 

Cold air feed is also very worthwhile, along with good heat shields. I have seen k+n's fitted inside airboxes. In fact, on my vitesse, I had a modified std airbox with the K+N elements inside. No bling, but a case of function over form. Another option would be to use the std airbox empty, and connect the tubes to a remote filter placed in front/to one side of the radiator.

Back reading so I would comment on the K & N's again.............I have K & N filters with sports exhaust and manifold, uprated the needles and springs and by all accounts have an extra 10/12 bhp ?? oh and by the way I'm 66 not a boy racer but do like efficiency............ have ordered the side valances because I like the idea of cooler engine/gearbox as it must push the air in that direction............... can you fir stub stacks inside pancake K & N's ?? I looked at them in the Moss book but couldn't decide.............thanks for your comments............keep 'em coming.

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I thought long and hard about K&N vs cold air feed. So I bought a temp probe from Maplins so that I could measure the air temp in the K&N whilst driving. Surprisingly it was around 40 deg C on a day where ambient was 18 ish when driving at 50 mph. The difference in density at those temperatures equates to around 2%. Not huge but worth having.

 

So I've now modded my filter air box by welding a strip in to make wide enough to fit the K&N's. Whilst doing it I also changed the 2 stubs by welding in 2 pieces of old stainless exhaust - 50mm dia vs the original 35ish.

The result is shown in the photo - if I can get the upload to work ...

post-156-0-96860400-1441226673_thumb.jpg

post-156-0-82635400-1441226706_thumb.jpg

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So I've now modded my filter air box by welding a strip in to make wide enough to fit the K&N's. Whilst doing it I also changed the 2 stubs by welding in 2 pieces of old stainless exhaust - 50mm dia vs the original 35ish.

 

Great stuff! But have you measured what difference it makes to the temperature?

 

Richard

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Yep - can't remember the precise numbers now, but was something like 15 deg c cooler (I think) at similar speeds - although not sure if the ambient temp was the same. I remember being surprised at how much difference it makes, at least in temperature terms. I bought an intake scoop from demon tweeks that I attached to the radiator side of the front grill, that means the flexi sucks the air from outside the car even when stationary.

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  • 4 weeks later...

Hi Alarman 49

 

Sorry I'm a bit late to this thread. My GT6Mk3 has never had side or radiator valances fitted in the last 29years and I've had no problem with engine cooling.

I'd partly disagree about upgrades-if they're done in conjunction with other mods then wothwhile gains can be made.

I find the main advantage to K&Ns is that they literally last a lifetime. The filter element is cleanable with the special K&N fluid. So over the piece they work out cheaper than the standard units. Short stub pipes can easily be fitted-I've had them since I bought the K&Ns.

I'd also disagree with the idea that an electric rad fan is not worthwhile. If this was the case we'd still see engine driven fans on cars today. Remember that today's driving is a completely different experience to that which was normal when our cars were built. There's much more stop/start motoring now and modern fuels tend to make engines run hotter. I've gone the whole hog and fitted a thermostatically controlled electric water pump as well. I've been glad of this combo on more than one occassion when stuck in long queues at the end of car shows. I've never suffered overheating unlike many of my peers in their standard cars.

I've also fitted a thermostatically controlled oil cooler-similar to the ones fitted in later Mk3s.

I realise that the GT6 has a more marginal cooling system than probably any other Triumph. Fitting a larger engine into what is essentially a Spitfire was always going to be a bit iffy with the limited space under the bonnet. So any help that can be given must surely be a good thing.

 

Cheers

 

Alan

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everyone loves or hates this topic,

   carburettors  do require a stable air temperature to maintain mixture setting , going hot to   cool as fans cut in/ cut out is not good for them

     an engine driven  fan  maintains  a  ventilated air flow under the bonnet al the time its running  its better at this.

 

 

    KN are fine so long as you can get a needle to match the  depression in the carb with its original spec developed by much testing by Triumph

     very few of us have  the  analysers  or test facility to really get this right,  because they make /allow more noise its felt they are better 

      no they are often slower on the stop watch but ... the  induction roar sounds good..

 

    electric fans on modern cars has a lot to do with the engine faces the wrong way unless its  Issigonis concept.

 

 

       just some ramblings 

 

Pete

 

 

   

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I have a Mk1 Spitfire with a Mk3 engine which ran very hot when I got it. I fitted radiator valances, the wider radiator, 7 blade mechanical fan and fresh coolant. No electric fan or engine bay valances and I have standard air filters. The car now runs a bit cold - just sits at the bottom of Normal even in traffic. Temp gauge doesn't get anywhere near halfway. I am now fitting a new thermostat as I suspect the previous owner tampered with it to try and keep it from overheating. I would like a bit more heat in the engine and in the cockpit!

I think the condition and age of the radiator and the coolant have a lot more bearing in engine temperature than any other component or modification.

 

I am new to TSSC and have picked up a lot of good tips from this forum - so thanks to everybody.

 

Cheers,

Roy

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If your mk1 has been fitted with a mklll you may have got the wrong temp sender

not well up on spitty evolution but early non stabilised gauges (move quick as soon as switched on)

Use 121997 and later stabilised (slow moving needle) use gtr108

many have had Hot readings and even changed engines because these have been inter mixed

cross match the sender with the stabilised/not stabilised and they read hotter than actual

 

 

just a thought when messing with hot readings

 

std thermostat is 82c for uk use it must have a jiggle pin in the rim to allow air out when filling

if its missing drill a 3 mm hole in the support rim or refilling will air lock.

 

pete

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  • 4 weeks later...

Found this.

Unfortunately its in pre-70s/ Old English/pre-metric AKA American temperature scale. -32 & divide by 1.8 to get Celsius.

It suggests you really need an ambient air feed to your filters. My inlet temperature is around 50c in traffic- time to change..

 

Cheers,

Iain.

 

post-1147-0-39428100-1446326296_thumb.jpg

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