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So leaving all the other stuff aside, I want to concentrate on getting this car to run more than a couple of miles.

The poor thing is suffering from fuel problems. As soon as it gets hot and under load, it starts sputtering and craps out on me. Leaving me stuck at the side of the road until it cools off again. Before it gets hot it runs just fine.

I rerouted the fuel line, so its not close to anywhere too hot, but I have triple carbs and headers, and it is HOT and I do mean HOT under the hood.

I'm suspecting that the carbs are overheating and vapor locking - they are so hot on top that I can barely touch them. My other thought was the tank, but it is fine - it does the same thing with the top off.

Does anyone else have this problem?
Is there a cure?
Does anyone make a heatshield for the triples, or am I barking up the wrong tree and it is something else entirely?
Is anyone running triples and a header? If so how hot does it get?
 
Sure get a hold of a good boiler man and buy a hard sheet of asbestos,if you can still get it. rivit/glue it on to a sheet of aluminun fabed to fit as a heat shield.
 
Hi Alan,

If the carbs are that hot to the touch, yes, I think heat is very likely to be causing problems.

I don't know of a manufacturer of a heat shield for the 6-cyl. TRs with a triple carb setup. You might check with TR6 specialists like www.goodparts.com. Joe Alexander makes heat shields for 4-cyl. TRs (SU and ZS), for Weber DCOE carbs, and for TR6 with dual SUs... nice stuff reasonably priced... www.the-vintage-racer.com. Perhaps he can make a shield to your specifications. Most heat shields are single layer, can really benefit from adding a secondary reflective surface that looks a little like Dynamat, but usually is a foil over some sort of high temp/fiberglass like materials, to create an air gap. This redirects the radiant heat away from the carbs even better than a single-layer metal shield.

A shield can help with radiant heat getting to the carbs, but won't solve ambient heat build-up. The only way to tame that is to keep heat inside the exhaust header and/or get more air flow through the engine compartment.

In addition to or instead of heat shielding, either ceramic coating (on mild steel) or wrapping (on stainless steel) headers can help a lot. This not only reduces the radiant heat coming off the headers and ambient heat build-up in the engine compartment, it keeps temps higher inside the header, which in turn helps gas speeds & flow for improved exhaust scavenging.

One thing you might try is temporarily running the car with the hood slightly opened, to allow air out the rear gap. Be careful doing this, perhaps adjust the latch if that's possible. This should vent air well and will tell you if underhood temp buildup is causing the problems.

Isn't the engine freshly rebuilt? There is usually more friction and somewhat higher temps in a fresh rebuild, during the break-in period.

Are there any overheating issues with the engine? For example, too lean a mixture can cause an engine to run hot, seen on the coolant gauge usually, but also producing hotter than normal exhaust gases. High performance upgrades can often make an engine run hotter, too.

Is there any obstruction keeping air flow from exiting around the bellhousing? That's the usual escape route. For example, thick heat insulation installed on the underside of the gearbox cover might actually interfere with air outflow from the engine compartment.

Do you have shrouding in place for the radiator. I'm wondering if air moving around the rad, i.e. not directed by any shrouding, might cause higher pressure buildup inside the engine compartment, sort of trapping air in place.

You might also consider some sort of fender vents, takes some work to install them opf course, but they make for an easy exit for hot air, that otherwise gets sort of dammed up inside the engine compartment.

Keep us posted!

/ubbthreads/images/graemlins/cheers.gif
 
Alan - to address your points:

Heatshield - I'll try the ones you noted. Thanks.

Headers - ARE ceramic coated, with jet hot. They are jet engine hot too!

Engine - Yes to freshly rebuilt, it has been engine dyno'd so should already be run in as part of that.

Temperature - goes to 3/4 rather than the 1/2 it did before.

Rad is stainless with a 16" fan as a puller and shrouded (also oil cooler). Fan works fine - pulls a lot of air through.

Could be lean I guess. I'll check that, also the hood open thing. Any other ideas?
 
Likely you're on the right track though a failing coil can also exhibit such symptoms (failing only when hot). Easy to check with a spare coil, just bungee it to the one mounted... or use an ohmmeter and read the coil cold & hot.

Will at least give you something to do while you stand at the side of the road watching it cool down.
 
Alan, aside what is available from time to time on ebay, TRF and I believe, Moss, now sell heat shields. Adding additional insulation would probably not hurt either, as suggested previously. Whether you can find asbestos may be iffy, but there are plenty of modern day alternatives on the market.

And.....good luck!
 
Just curious, did the headers get coated on the inside as well as the outside? I bought mine from JetHot, so they were done both in and out. Mine do get hot, but don't affect my carbs and they do cool down much faster than the old cast manifold ever did. I rarely ever go above 1/2 even in traffic in this hot weather.

Which reminds me, now that mine has cooled off from a hard blast up and down RT 95, it's time to go out to the garage and add some Water Wetter, just as an insurance policy. Did you add any of that when you filled with coolant? BritsBits techs and my guy all swear by it to help keep cooler.
 
Alan,
Is your fuel tank properly vented? Is the evap system functioning correctly?
A improperly vented fuel tank or a malfunctioning evap system will mimick vapor lock.
I thought I had a heat/vapor lock issue last year when I discovered that my fuel tank was not vented. Corrected that issue and all has been fine since. FWIW
Good Luck!
/ubbthreads/images/graemlins/driving.gif
 
I ran it with the filler top open.
Same story as with it closed...

Its way too hot under hood.
I have to figure out why.
I hope its just running lean or something stupid like that...
 
Alan, if you can get to a state inspection or emissions tester, you will be able to tweak those carbs perfectly and determine exactly how rich or lean you really are. I don't know what is used in NY, but the good tuning and emissions guys in RI make more setting up performance engines than doing state inspections.
 
Alan,
Whereas I have a similar setup to you, I am concerned that all these band-aids to the heat issue aren't addressing the real problem of why you are emitting so darn much heat! When you say even your carbs are too hot to touch, ouch. That means that there is excessive heat build-up in your head. Way-lean mixture, excessive plug gap, valves-cam set wrong, inadequate lube in head. Or, heaven forbid, something is/has failed in your head and hasn't manifested itself in the form of a really ugly noise or a breakdown. But that kind of killer heat is not normal. Why not call Richard Good and pass a few of your questions by him.

Have you tried shooting a temp of your head at it's hottest and posting that for comparison. I might do the same today.


Bill
 
Bill, I agree wholeheartedly.

I'm going to check the plugs today, and see if it looks lean. I'm glad you responded about your underhood temp - I'm sure now mine is excessive, and thats causing the car to die because of fuel vaporization.

My problem here is that as I've said before I'm a total muppet with carbs. I'm going to be standing screwdriver in one hand, manual in the other today.
 
I also agree with Bill and would look at cam/valve timing and also valve adjustment. Possible cam lobes worn down with defective cam or bad break-in.
 
I think it is probably a set up problem as well. When I first got my 6 it would overheat if not kept moving at highway speeds (the cast iron manifold would glow red). flushed the system, new radiator, and had it properly tuned, then I never had the problem again. Being as your radiator is new and definetly capable of cooling your current HP output, I would lean towards improper set up. Also, when my car did get thoroughly heat soaked it would die, and run very poorly.

As far as tuning the car, I would lean towards pig rich, safer and definetly won't damage your new work of art.
 
Its way lean. Stalls when I lift any one of the pistons.

I need to get the tool to adjust the carbs then we'll see if gets better...
 
Way lean makes sense for that level of heat. My stainless header is not ceramic coated, not wrapped with heat tape or anything else. Yet, it runs just fine in 100 degree weather. No stalling, vapor locking hasn't really been a problem either, heat soaking the starter, that's an entirely different matter. I need to put the insulation back onto the gear reduction starter then it should be okay.

I should clarify that the car can run longer in the 100 degree weather than I care to be in it. Man yesterday was hot. I was actually feeling a bit jealous of Miata's that had their tops up and the A/C on. Though a few did roll down their windows to hear my exhaust. /ubbthreads/images/graemlins/grin.gif

I did see a chap on Ebay (from the UK I believe) that was selling both twin and triple carb heat shields for TR's.
ebay link I've been considering these or something like it for mine. Even though I don't currently have a problem with vapor lock, I can't help but think that all that heat is still taking a toll on the carbs (gaskets, diaphragms etc...).

Popping the hood won't really work for cooling at speed. The negative pressure at the base of the windscreen will force air under the hood from the rear, not let it out. Think cowl induction hood scoop here. Bill's vents over his carbs are not for heat evacuation, they are for increasing air to the carbs at speed. Airflow can be very counter intuitive at times. /ubbthreads/images/graemlins/confused.gif

I know how you feel about the under 2,000rpm though. My engine really wakes up at and likes to pull from about 2,500 all the way to 6,000rpm. But will not idle smoothly below 1,100rpm. If i'm cruising and the rpm's drop below 2k for long then the carbs begin to load up (Wonder if that is a partial heat related symptom?). This really makes it a pain to drive in traffic. Something that will probably increase thanks to Money magazine naming Fort Collins the number one place to live in America. Great. /ubbthreads/images/graemlins/tongue.gif

I'm wondering how well your engine was set up on the dyno. Do you have air fuel ratios readings along with horsepower and torque graphs? If so, what happened to the mixture setting between the dyno shop and re-installation/delivery?

Just out of curiosity, did the mechanic offer any sort of warranty or did he consider this 'high performance/racing' work and no warranty? If he offers to make it right through tuning he should come to your house and so it there. Or at least pay for the tow back to his shop.

Keep at it, we'll help as much as we can. /ubbthreads/images/graemlins/grouphug.gif

/ubbthreads/images/graemlins/cheers.gif
 
The mechanic is on vacation for a couple of weeks. He rushed to get it ready - note choice of verb here - before he left.

Its going back regardless because it leaks oil all over. It is coming from the rear of the engine, and from somewhere around the gearbox (I haven't looked yet to see exactly where). I want to get it running so I can have at least a short drive in it without being stranded at the roadside. It is just a lump of metal taking up space otherwise.

I also want to see if the rebuilt distributor I have really has a problem before I send it back, or if the mechanic is an even bigger tool than I'm starting to think he is. I can't face trying that until I get it to run for more than a few minutes at a time though. One change at a time...
 
Heat is a killer with lbc's Tr or the other(mg)'s...Its kinda like tracking down Lord Lucas;ALL of the advice is VERY GOOD but the heat is killing the motor,thus venting the heat i'm afraid is the answer.I would look into getting some vents installed in correct locations on the bonnet or sides of the bonnet.It would be like a testimonial to the vents on the GT6.,the engineers new they had a developing problem,they nipped it in the bud by installing vents.A good body shop will install vents YOU buy from Eastwood or any good distributor for probably under $200.00,It would be a sooner the better proposition in my regard,My little 80 Spit was suffering heat prostation UNTIL i installed the proper heat shield.THEN it ALL went away.Good Luck Alana
 
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