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In a previous post, a few of you commented that my VS standard issue exhaust isn’t helping my 1915cc engine. For one, it may well be contributing to my engine running hot when stuck in our infamous CA traffic. 

A little background, the only “upgrade” I have done to date to my 2013 VS 1915cc engine is a CB Performance 2-qt wide glide oil sump (1709).

A local VW mechanic recommended a CB Performance 3510 A-1 Sidewinder Ceramic Coates exhaust for my speedster, as a method to assist it running a bit cooler when stopped.

https://www.cbperformance.com/product-p/3510.htm

I thought I would bring this suggestion to the group before I ordered.

As a side note, I do much prefer the dual exhaust out of the back versus the single.  I don’t know if that is a drawback or not.

As mentioned in my earlier post, the car maintains 195-210 degrees (verified by an un-verified candy thermometer in the dipstick) when running at 70-75mph on the freeway.  It also maintains those temps when driving on backroads between 25mph-50mph.

I only start getting anxious when stopped in heavy traffic.  Especially when outside temps are 85-degrees and above.  What I have been doing to remedy this is to review weather against normal traffic patterns, before setting out on my adventures. If temps are 85-degrees on a route that normally has heavy traffic patterns, I take my daily driver  

 

  

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Original Post

 

Kevin, I don't think just bolting on a better exhaust is going to solve your overheating issues. Things might improve a little, or maybe not, but the fundamental problem will still be there.

Which is that the VS 1915 was never a coordinated high-performance design. Basically, they just bolted bigger cylinders onto a stock 1600 without changing anything else. It does indeed displace 1915cc, so VS could call it an 'upgrade' and charge more for it. But it didn't make much more power than a 1600, although it probably made more heat.

Mine did, and I had pretty much the same overheating in traffic that you're seeing.

The design of these engines needs to be carefully thought out. All the bits need to be chosen and set up to work with each other. Crank, cam, heads, valves, compression, carbs, exhaust, oil flow, and many other details. And it all needs to be screwed together by someone who knows what they're doing.

If you get it wrong, you can end up with the paradox of a weak engine that also overheats.

Ask me how I know.

One thing you must tell us is if you have an external oil cooler or not and where it's mounted. As I said in my reply to your recent post in another thread, this could be a major cause of your overheating if you have the standard VS cooler mounted in their standard location.

I'd strongly suggest you call @Anthony at Anthony's Classic Motor Werks in Auburn and explain the problem to him. He's seen this all before, many times. He'll give you an honest assessment of the best options.

Bolting on new parts in the hope that they'll fix a problem can be an expensive guessing game. It's better to have a well thought-out plan.

Cheers!

 

Last edited by Sacto Mitch

 

Kevin, if you're not running an external cooler and the engine stays cool most of the time, adding a decent cooler in the rear wheel well will almost certainly solve the problem.

The Speedster engine compartment was never designed to dissipate the heat our engines make, so the internal cooler is usually overwhelmed in tough conditions - like stop and go traffic on a hot day.

But, I'd give Anthony a call and see what he recommends.

 

Keep in mind what Mitch mentioned. "there's a lot of things to consider" It's the picture, getting everything to work together and efficiently.  such as a full flow system with a remote cooler and fan, remote oil filter, timing and jetting properly set, good sealing from exhaust into engine compartment, good air circulation into engine bay.

I can go on but I think one would understand where I am going.  the initial engine combos available had been a stock crank with big bore and stock valve heads. it wouldn't matter how big of a cam you ran, the small valves and ports would choke the motor's power and efficiency.

Kevin - Bay Area posted:

I only start getting anxious when stopped in heavy traffic.  Especially when outside temps are 85-degrees and above.  What I have been doing to remedy this is to review weather against normal traffic patterns, before setting out on my adventures. If temps are 85-degrees on a route that normally has heavy traffic patterns, I take my daily driver  

 

  

the heavy traffic issue is due to air flow. when the cars moving your having air flow due to the fan pulling more air over the engine and cooler. what would help is a setrab fan pack oil cooler. these units are by far the best available. Ask @Mitch or @Terrynuckles

Thanks everyone for weighing in. 

Pardon my next question, as it may come off as a bit naive. But is the stock 1915cc engine really that much quicker than a 1600cc engine?

Does the 1600cc engine tend to run cooler?

Just weighing my options here. If I understand correctly, adding an oil cooler may solve my issue. Or it may be the first part in a series of items I’ll need to purchase in order to get the operating temps down when in traffic.  (Which I guess is all part of the madness)

Which gets me back to my question above (in terms of the difference in speed between the 1600 versus the 1915). For my purposes, what I have so far has been great in terms of quickness (or lack there of). I enjoy cruising around in the car, whether is be the back mountain roads by my house, cruising at 70-75mph on the highways, or driving 55mph on the backroads of wine country. 

 

@Anthony As Sacto Mitch pointed out, I should just plan a day’s visit to you before I start purchasing parts. 

My own experience is that I have owned 2-3 VW Beetles over the years that were about 1600cc and my first Speedster engine was a 1915.  The difference in power to me was dramatic.  The 1915 would run cool all day at 70-75.  Maybe it's just me but I personally wouldn't do big road trips in a 1600.  To the ice cream store sure but not interstate driving.   

I agree with Jack completely. I drove a Speedster with a bone stock 1600 from Idaho to Ottawa, Canada and a year later the same Speedster from Sacramento to Ottawa, Canada with a basic single carb 1915. The difference was dramatic. First engine was reliable but hardly suitable for travelling on the freeways while the 1915 was much better suited to the task and more fun to drive the distance. Same stock transmission both times. No cooling problems either time but we didn't spend time in hot, congested traffic. No external cooling parts on either engine. 

Last edited by David Stroud IM Roadster D

Keep in mind that a speedster is a few hundred pounds lighter than a  VW beetle, Some of the speedsters I have done had 1600 / 1641cc engines wand if they are set up right they run along the highways just fine and of course stay cool.    You can run up to a 1915 cc engine with out an external cooler , anything above the 1915 you have to provide additional cooling features.

Kevin,

It's a great simplification, but I've heard an internal combustion engine described an air pump. The engine's got to breathe: air in, air out. Anything impeding the flow of the air in and out creates problems.

A few months back, I posted about why an actual 4/1 header is a miracle of physics, actually creating a vacuum on each opening valve in the engine, helping air move through. When I have more time, I'll find it and send you a link-- but for now, yes-- the exhaust that is appropriate to your particular engine will help.

What Anthony was addressing above is that everything has to work together. Another limiting factor in your engine could be the heads. Smart people harp all the time that "the power is in the heads". Well designed heads flow more air, without increasing port volume to the point that the engine gets "lazy". That's why all the ads spout the CFM rating of heads-- they're telling you how much air can move through the heads. They don't tell you about how big the ports had to get to flow that much, but there's a shortcut there as well-- intake port volume. There's a cool little sticky over on TheSamba that has a chart that's updated constantly, as new heads come to market:

From this chart, you can (or maybe not, because it's so small) that a CB Panchito head flows 167 CFM at .500 of valve lift, with an intake runner volume of 61 cc. The CB Super Mags are almost identical in flow and intake runner volume, but they're a CNCed head, where the Pancitos are "as cast" in the ports. If I'm not mistaken, the old Vintage Speedster 1915 used stock big-valve heads with no porting. 043 VW heads flow 117 CFM at .500 of valve lift, and have an intake runner volume of 57 cc. So you can see how much better the Pancitos and Super Mags are than the heads that are on a "stock 1914" engine. The port volume is nearly identical, and the flow numbers are almost twice as good. 

Suffice it to say, there's way more here than just numbers. There's flow characteristics that smart guys spend a lifetime learning about. The cam and the heads work together. The heads will only allow as much flow as the cam is asking for, so just sticking better heads on it without matching a nice cam to it is a waste of money.

The last thing to think about as it pertains to the internals of the engine is the intake side of the engine. Are the carburetors a choke point? If you've got duals, probably not. If you have a stock 1 bbl, yes-- it's a choke point.

What we all seem to forget about is how much air is actually available for the engine to pump. The 356 speedster body is beautiful, but it puts the air intake for the engine is a low pressure zone. Speedsters stink at getting air to the engine to use to pump and cool. Terry Nuckels noted a couple of interesting things pertaining to airflow. Firstly that popping the deck-lid and propping it open a couple of inches really helps. I saw a major improvement driving through the desert this way back on one of my epic road-trips. The second thing is even weirder-- he also found that carrying a suitcase on the rack seems to improve the ability of the car to cool as well. I assume this is due to changing the airflow around the back of the car, but I have no idea how. He says it works, and he knows what he's talking about.

Of course, an external cooler is a good idea, but you need thermostats to control when oil is flowing through the cooler, and when the fan turns on, etc. It's also got to be mounted in the right place to work well-- there seems to be a lot of "bad" places to put one, and only a few good ones. The driver's side wheelwell works well.

Good luck. Forewarned is forearmed.

 

You need to post some pictures of your engine - top and bottom.  There may be an easily spotted issue - missing engine tin, unplugged heater tubes, missing air seals around the plugs, no Hoover bit, missing deflectors around cylinders, exhaust gases free to enter engine, missing tin/air leaks around dog house cooler (bottom piece is often missing), aftermarket shroud with no internal vanes, chrome cooling tins, etc.

Most VS engine bays I've seen have a round ~5" air inlet in the firewall (behind fan intake to right a couple inches) covered with a mesh screen - does your have it?  Note - VS in photo also has rubber seal completely around the engine lid - great for keeping rain water AND extra needed air out. Other have made a prop that keeps engine lid open a couple inches when driving to let in extra air.

Late 1975+ FI bugs and 356 Porsches (first used on the 4 cam 550 engine) added something called a Venturi ring to smooth/increase air flow into the engine cooling fan/shroud.  From AirCooled net -

Venturi Ring for Fan Shroud (Fan Inlet Velocity Stack), Black Powder Coated, All Doghouse Fan Shrouds
Venturi Ring for Fan Shroud [Fan Inlet Velocity Stack), Black Powder Coated, All Doghouse Fan Shrouds


 
 
 
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Venturi Ring for Fan Shroud, Stainless Steel Black Powder Coated, All Doghouse Fan Shrouds significantly improves airflow and cooling by reducing turbulence of air entering the fan. All stainless steel construction, with spot welded mounting tabs for an EZ install. Increase your cooling air by 10% with no other changes! The venturi shaped ring smooths air entry into the fan, and less turbulence means more airflow and better cooling! VW added these to the FI fan shrouds, since those engines had such a tough time keeping cool, and now these are available for you to add to your doghouse fan shroud! These operate on the same principle that a Velocity Stack does to increase airflow into a carburetor!

This can be either riveted or welded to the fan shroud, using the included mounting tabs.

Price: $59.95 

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Last edited by WOLFGANG

How bout plumbing used to splain lectricity ?  Water pressure=volts,  Gallons per minute=amps,  smaller pipe size=resistance,  check valves=diodes,  water pumps=alternators,  water turbine's=electric motors,  pressure accumulators=condensers,  flow restrictors=resistors,  valves=switches,  diverter valves=two & three way switches,  water pressure reducers=transformers, storage tanks=batteries.......all about control ?

Uncontrolled electricity=lightening,  uncontrolled water=flooding............Bruce

Kevin - Bay Area posted:

Thanks everyone for weighing in. 

Pardon my next question, as it may come off as a bit naive. But is the stock 1915cc engine really that much quicker than a 1600cc engine?

Does the 1600cc engine tend to run cooler?

Just weighing my options here. If I understand correctly, adding an oil cooler may solve my issue. Or it may be the first part in a series of items I’ll need to purchase in order to get the operating temps down when in traffic.  (Which I guess is all part of the madness)

Which gets me back to my question above (in terms of the difference in speed between the 1600 versus the 1915). For my purposes, what I have so far has been great in terms of quickness (or lack there of). I enjoy cruising around in the car, whether is be the back mountain roads by my house, cruising at 70-75mph on the highways, or driving 55mph on the backroads of wine country. 

 

@Anthony As Sacto Mitch pointed out, I should just plan a day’s visit to you before I start purchasing parts. 

A: Your stock VS 1915 is stronger than a stock VW 1600 and probably about as strong as a "Super 90" Porsche 1600 from back in the day. 

More is more.

That said, the engine in your car does not drive like the Super 90. That engine made 89 horsepower at 5500 RPM and 89 ft-lbs torque at 4400. 

Your 1915 makes about 75 horses at about 4500 but probably close to 100 ft-lbs of torque at 3500. It feels stronger at lower RPMs—because it is; that's what those extra CCs give you. But it runs out of breath at higher RPMs because, as Stan noted, it's not really "built" except for the bigger cylinders and dual carbs.

A good 4-into-1 header (like a sidewinder) will help the engine, but only if the tubes are sized right. In your case you want 1.5 inch primaries. The good news is they'll be "right" for this engine even if you later build it up. They're also right for a small stroker of 2 or 2.1 liters.

The power these mills make is quite variable.

It is possible (though not advisable, at least in a street car) to wring 200 horsepower from a 1915. 

Pat Downs offers engine kits of the same displacement with an advertised 125 horsepower at 5500 RPM. That's about what the 1915 I'm putting in my Spyder is supposed to make. Carey Hines at Beck/Special Edition has been using these as his "standard" engine for well over a decade. 

Double the power of a stock 1600 VW engine. 

The 1600 will run cooler than a 1915, all things being equal.

But a lot of 1915s, and even larger engines, run as cool as a stock 1600. It's all in how they're put together--right components, proper assembly, careful attention to detail. 

Last edited by edsnova
WOLFGANG posted:

You need to post some pictures of your engine - top and bottom.  There may be an easily spotted issue - missing engine tin, unplugged heater tubes, missing air seals around the plugs, no Hoover bit, missing deflectors around cylinders, exhaust gases free to enter engine, missing tin/air leaks around dog house cooler (bottom piece is often missing), aftermarket shroud with no internal vanes, chrome cooling tins, etc.

Most VS engine bays I've seen have a round ~5" air inlet in the firewall (behind fan intake to right a couple inches) covered with a mesh screen - does your have it?  Note - VS in photo also has rubber seal completely around the engine lid - great for keeping rain water AND extra needed air out. Other have made a prop that keeps engine lid open a couple inches when driving to let in extra air.

Late 1975+ FI bugs and 356 Porsches (first used on the 4 cam 550 engine) added something called a Venturi ring to smooth/increase air flow into the engine cooling fan/shroud.  From AirCooled net -

Venturi Ring for Fan Shroud (Fan Inlet Velocity Stack), Black Powder Coated, All Doghouse Fan Shrouds
Venturi Ring for Fan Shroud [Fan Inlet Velocity Stack), Black Powder Coated, All Doghouse Fan Shrouds


 
 
 
Additional Photos

   
Venturi Ring for Fan Shroud, Stainless Steel Black Powder Coated, All Doghouse Fan Shrouds significantly improves airflow and cooling by reducing turbulence of air entering the fan. All stainless steel construction, with spot welded mounting tabs for an EZ install. Increase your cooling air by 10% with no other changes! The venturi shaped ring smooths air entry into the fan, and less turbulence means more airflow and better cooling! VW added these to the FI fan shrouds, since those engines had such a tough time keeping cool, and now these are available for you to add to your doghouse fan shroud! These operate on the same principle that a Velocity Stack does to increase airflow into a carburetor!

This can be either riveted or welded to the fan shroud, using the included mounting tabs.

Price: $59.95 

@WOLFGANG Thanks for the advice.  I will snap some photos when it stops raining.  That said, I actually believe the photo you used IS my engine bay (before I painted the air cleaner covers Porsche aluminum, and added the yellow valve clearance decal on my fan shroud) .  I'll have to check it out and compare....but I haven't found too many speedsters that have my Irish Green color--only have come across one other.

Your responses exemplify the power of this group; from the various comments I have received in the past 24 hours, to highlighting a potential issue on a found image (which may very well be my engine bay) to providing an amazing chart comparing CFMs of a variety of heads on the market. 

Thank you. 

I have uploaded a number of photos I just snapped of my engine bay, and underside of the car. Hoping this helps. 

To add, I’ve put on 6,000+ miles on my speedster in the past 25 months how long I’ve owned the Speedster). Perhaps I’m making mountains out of molehills here. Obviously my “issues” haven’t kept me from having a fun time in my car. I just curtail my experiences around temps and traffic conditions. I’ve been stuck in some major bummers of traffic jams; at which point my anxiety levels rise with my wonderful Chinese temperature gauge.  My oil has been changed (and valves adjusted) three times since taking possession; the last two times the oil was not dark and thick, only slightly different in tone than when it went in. 

Thanks again for your comments, assistance and feedback.

 

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Is the Chinese gauge the only thing that indicates to you that you are over heating?  Wow, I see absolutely no oil leaks! By how much?  Some recommend a candy thermometer to measure oil temp down the dispstick tube --- or a known accurate oild temp gauge.  I would do search and make the quick and easy hood prop to keep engine lid open a couple inches when in traffic.

Looks like all the cooling tine is there - can't see the dog house cooler though.  Looks like aftermarket shroud - the OEM on has internal vanes and directs air flow better.  Does it have the thermostat and flappers (for quick warmup)? I've seen others block off air to the heat exchanges (with plugs at shroud outlets) in the summer when heat isn't used.  The way heat exchangers work when hot air not going to intereior is to dump it at the front of the engine (where it ofter get ingested again -especially when sitting in traffic with no air flow under car). Looks like exhaust leaks (carbon black tracks) where heat exchangers attach to exhaust on each side).  A ceramic coated muffler will expell heat better than non treated one. 

If an engine has stock heads, a bigger bore, and a stock-ish exhaust, it'll overheat in traffic on an 85* day. I had just such an engine in the first two cars I owned. We don't have much stop-n-go traffic here, but it gets 95* and both 1776s overheated. 

There are lots of things you can do to bring the temps down incrementally. Ceramic coating the muffler and installing a venturi ring is going to be good for about .0001% of what ails you.

By far, the most bang for your buck is going to come from 2 things:

1) a 96 plate (or better) remote oil cooler, with a thermostatically controlled fan and bypass.

2) a quality free-flowing 4/1 header exhaust.

Neither are cheap, but both together will fix your issue.

Timing and setting up the carbs is # 1. Good air in and bad air out,   because the engine bay tends to create negative air bubble, I open 1.25" across the bottom of the bulk head and take a bit off the underside of the deck lid opening ...a basic combo for all engines up to 1915cc. For larger displacement engines, I also bore a few 1.5" holes in both the left and right vertical fiberglass , cut and finish trim a license plate opening  behind the tag and a  fan forced oil cooler. Works for me,  your mileage may vary.

Last edited by Alan Merklin

One thing I noticed in your pics is the engine doesn't have the rear cylinder deflectors (#5- 1 on each side), although I don't think just those missing would cause the temp issues you're having in stop and go traffic. Is the oil cooler exhaust duct (#9) in place? I wonder if it should be extended to get it further away from the firewall hole.

engine tin- dual port

The rear engine seal looks good, I'm assuming all the spark plug seals are in decent shape and the engine is in good tune as well? 

I'm kind of rambling here- with a car that does ok when moving but has temperature problems in traffic I'm thinking that if there's enough air to the engine (fan, carbs) and airflow through the engine compartment to remove the radiated heat from the engine's external surfaces when the car is moving (so it's not re-ingesting pre-heated air) but has problems at slower speeds on hotter days, I'm guessing that IT IS RE-INGESTING PRE-HEATED AIR AT SLOWER SPEEDS and on hotter days the engine can't cool itself adequately at these lower speeds because there's not enough air movement through the engine compartment to remove said radiated heat. A remote thermometer in the engine compartment would confirm what's going on under the various conditions- any more than a few degrees above ambient and you know the engine is re-ingesting pre-heated air.

Alan's 'hole under the licence plate' suggestion (don't forget to space the plate 1/2" away from the body) is a great idea but I don't think it will help here. As Stan (and others?) said, a properly designed 4 into 1 header (get it ceramic coated so it radiates less heat) will help, but may not be the complete answer. An auxiliary cooler would get oil temps down, but I think a cht (cylinder head temp) gauge would show head temps still getting too high. You'd be treating the symptom and not the cause, and with enough time in slow moving traffic the heads could happily cook themselves into oblivion, dropping a seat, spitting out a guide or breaking an exhaust valve (that one is really messy, as it will probably take out a piston as well!) some where down the road (and never close to home!). Heads will not be rebuildable...

  You also don't have a full flow filter so adding a cooler is more work- a full flow pump cover with the hose fitting isn't a big deal to install (you will have to remove the pump and block off the exit port), but the engine will have to be stripped a bit (pulley and associated sheet metal) to install the return fitting in the case. I have heard of it being done in the car- feed some air pressure into the case so the chips from drilling and tapping blow out. Of course, it would be a great time to add a full flow filter as well.

At this point you're still treating the symptom (hot oil) and not the cause, though- the engine is still re-ingesting pre-heated air at slower speeds. You could drive around with the engine lid open to release the hot air (Beetle owners do the same thing with hood stand offs), but you may or may not think your car looks a little silly driving around like this.

Again- at slower speeds the engine is re-ingesting it's own spent heat. Radiated heat from the engine itself keeps re-entering the engine (through the fan and carbs), getting hotter and hotter, and with heater boxes, the hole in the firewall is allowing hotter than ambient air into the engine compartment as well (I think Wolfie already said this). The fix (I think) is to remove that heat from the engine compartment (and prevent the hot air from the heater boxes entering) by force feeding it cooler air. I've heard of people suggesting putting computer fans in the firewall, but I don't think they'd move enough air to be effective, but a bilge blower pump (3"- 135 cfm, 4"- 235 cfm)                                                 https://www.amazon.ca/Rule-140...8AZ8K?th=1&psc=1                                                                                                                        mounted above the trans, drawing air from down low, just behind the torsion bar and plumbed to the firewall (a new hole above and to the left of the fan intake?) may be just the ticket. Now the hole behind the licence plate (that Alan suggested) becomes an exit point and much more effective. On my engine lid the air access openings (on the sides)  are pretty small- I calculated about 12 square inches, whereas someone on the Samba said the vents below the rear window on a beetle were about 30 sq. " and the vents in the engine lid added 15- 30 sq " as well, so our cars definitely need more air access.

I probably have more to say, but I think it's time to go back to bed...

Often the dog house oil cooler air ducts are put on carelessly (or missing the lower pieces).  Here's photo a a well sealed complete one - even uses foam to ensure good seal. Is the Hoover bit missing in photo? Ha, doesn't look like spark plugs seals are sealing as well as they could (probably old rubber seals).

Related image

On diagrm below it looks like #9 and # 10 are missing - might be what Al refered to but his diagram doesn't show up for me. They are easy to add.  My engine has a rubber sealling ring around the hoses from shroud to heat exchanges where it goes thru the rear breast plate (to prevent exhaust gases from being re-ingested and sucked back up)

Image result for vw bug engine tin diagram

Last edited by WOLFGANG

I almost never disagree with Al (ALB)... but I always have (and probably always will) respectfully disagree with how he views airflow inside the engine bay.

The fan on the engine moves more air than you can imagine. The engine will always pull air from the engine compartment and discharge it to the bottom. Any hole in the engine bay (be it through the deck-lid, license plate hole, wheel-well hole, or firewall hole) is going to be a place for air to get in, not to let it out. 

It's clear that something is happening with the air when the car isn't moving, and that the engine must be reingesting hot air. It's clear that the engine is going to radiate heat when it isn't moving (and when it is), and it's possible that at low RPMs, the fan isn't moving enough air to overcome a rise in the engine compartment temperature. Regardless, that fan is still moving more air than you think, and the heat isn't flowing out of the holes in the engine bay. Something else is happening in stop an go traffic.

Any time somebody posts a picture of a car without surround tins, we jump on him like a fat kid on cake, because we intuit that the air coming into the engine compartment should be as cool as possible. I'm pretty sure these surround tins make exactly zero difference when the car is moving down the road, and may even make the situation worse because the air under the car (when it's moving down the road at a decent clip) is not preheated-- because the vehicle is in motion, and the car is not riding on a bubble of air. Any hot air flowing out the bottom or off the exhaust is dozens of feet behind the car by as it moves along. It's when the car is stopped, or barely moving that those tins come into play.

I've tried the big honkin' holes in the firewall with big honkin' fans-- and it actually makes no difference under normal speeds, and makes the situation worse in stop and go traffic. I suspect this is because any air I'm getting from the front (firewall) side of the engine is hot air that has already been though the doghouse cooler. I also suspect that leaving a gap at the breastplate, or drawing air from the wheelwells is just more of the same-- hot air that the engine has already heated, rolling out from under the car when it's stopped. The standard A1 method of dumping the exhaust under the car, rather than out the back is madness of the first order.

What can be done? A lot of this is just baked in the cake-- a speedster engine compartment is a little bitty thing with it's air intake grill sitting in the worst place on a vehicle to try to draw in air (the low pressure zone at the back of the car). The hole behind the license plate it at least clean (not preheated) air, but this is an even lower pressure zone when the car is in motion, although I suspect it would be better when the vehicle is stopped or in stop and go traffic.

I plan (LORD willing) to get the car painted next winter. When I do, I plan to open up the deck lid as much as possible, probably removing all of the rain-tray apparatus. Will it be enough? Probably not, and it'll make driving in the rain a pretty thankless endeavor, but the alternative is to prop the hood open any time it gets hot, and that's pretty unsightly.

There isn't a great solution, which is why we try to optimize the configuration of the engine and deal with the symptoms of overheating. It isn't perfect, but until somebody builds a Baja Speedster, we deal with the limitations of what we've got.

Last edited by Stan Galat

Stan.  The rain tray is a culprit in this problem. The actual "open" area at the sides of it underneath are the restriction. The square inches of open area is about 1 third the open area of the grill. Yes, opening the lid will solve that problem but, IMO, ruin the look of the car. Porsches with two grills have a highly modified rain tray. They knew there was a problem.  I didn't get to modify the rain tray on my Speedster before I sold it but it was next on my list to modify it by making a new one that had nearly 3 time the open area and still kept the rain out. I took measutments of how much room I had to play with by using crushable bio foam with a lid that had no rain tray. This told me how much room I had to play with between my engine and the grill. Because we seem to all have different engines configurations, my lid may not have fit on other cars but I Do think that the body builders should redo the size and shape of the rain tray.  We really could get along with out a rain tray out here in SoCal but I believe you guys back there really need one................Bruce

I'm no thermos engineer and don't know a hell of lot about engine heat and dissipation, but I fell onto something that solved my overheating problem in a Gazelle and 550 Spyder I built. Both 1600cc engines were upgraded with bolt-on larger jugs and neither car had sealed engine compartments. Both engines had heat sensors and gauges and would overheat while standing still (South Florida). While picking up some oil at my local auto store I noticed a can advertising 100% synthetic and part of the specs on the side of the can mentioned  better cooling than traditional oils. I gave it a try, whether it was my imagination or not but no more overheating problems. I've not seen the oil on the shelves lately but I think it was called Xonix or Zonix.

@Kevin - Bay Area

Sounds like you car runs fine (engine heat) while you're at cruising speed but heats up in traffic.

FWIW, here is a method used by several SOCers (myself included) to help keep an engine cooler in higher temps while in traffic.

Here is the method that Terry Nuckels used. Inexpensive and super easy to install. Others have posted many variations of this method, but Terry's is the simplest.

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I've McGuyvered a similar engine lid prop on my car. It helped keep the engine cooler in heavy traffic.

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Ultimately, having your engine free-flowed and installing a remote oil cooler with thermostat fan is best. Until then this method should help your issue. Hope this helps! 

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Last edited by MusbJim
WOLFGANG posted:

You need to post some pictures of your engine - top and bottom.  There may be an easily spotted issue - missing engine tin, unplugged heater tubes, missing air seals around the plugs, no Hoover bit, missing deflectors around cylinders, exhaust gases free to enter engine, missing tin/air leaks around dog house cooler (bottom piece is often missing), aftermarket shroud with no internal vanes, chrome cooling tins, etc.

 
  

Please pardon my ignorance, but what is a "Hoover bit"? That's a term I've never heard before.

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