CMC Speedster running hot follow up

I think you should not have closed off the circular hole in front of the engine.

I don't know the whole story of what you are running for an engine but I assume some version of a type 1 VW. If you have all the engine bay sealed so the cool air coming in is separated from the hot air coming off the engine and out underneath the car and you are still running hot then it is one of the following. You timing is not set correctly possible too retarded. The fuel mixture is way lean caused by incorrect carb jetting or a vacuum leak. I have also found a shop rag that got sucked into the fan and what's left of it laying on top of two cylinders thus blocking the cooling air. Rats, mice and other pests can build nests on top of the engine under the fan shroud and block the cooling air also.

I can't for my life understand (maybe someone else will enlighten me) figure out why a mechanic would tell you to run 87 octane. In my experience running the highest octane non race gas you can find in these little air cooled engines is best. Running them a little rich will help them run cooler as well. It will cost you some miles in engine longevity but we don't tend to drive our cars more than 10-15k miles in the the time we own them, (I know there are exceptions).  Here in Indiana 94 octane is at the pump. We can also get 110 octane race gas at many gas stations, we are in Indiana the home of racing. Good luck getting your baby sorted. When you get it just right the joy of driving her will be immense!

Don't block that 1/2 moon circular area in front of the engine -- that's for the cooling fan to suck up fresh cooler air!  I see the bus H gasket on either side of engine --- but not across the back above the exhaust. (Build manual has 2 shields in that area to keep exhaust heat out of engine bay).  I'd trim the tin and continue the H gasket there. Some have cut out area behind the rear license plate.

What size engine?  Any added oil sump of external cooling/oil filter?  Stock 2.5 quarts just isn't much oil in a hopped up air cooled engine.  Are there lower cooling tins (sled tins) below heat exchangers/J tubes - to direct heat out to rear.

Octane, timing, mixture all influence heat generated by engine.  Exhaust too -- a ceramic coated exhaust gets heat away from engine.  Remote oil cooler with electric fan can increase oil capacity and its cooling. Some have mad a 2-3" prop to keep back of engine lid slightly open too.

Love those wheels!

I can't tell, but it does not look like you have all the doghouse tin in place over the cooler. The doghouse tin ducts the superheated spent air from the oil cooler BELOW the engine tin, rather than inside the engine bay. This could be the source of your high cylinder head temps, but could also be any of the things Jimmy stated.

Also it could simply be carbon buildup has upped compression and caused the overheating to occur. How do the spark plugs look?

The tin over the cooler everyone has(the one with the Porsche shield sticker). The two after it that fit into a special front firewall tin(not shown here) are the three pieces you may need.

I'm with Jimmy on octane. 91-93 is available everywhere. Ten percent ethanol actually HELPS with cylinder cooling and detonation resistance.

@DannyP

@DannyP i just went over to my ebike shop and took a bunch of photos to try to show you what i have there as im not mechanically inclined and some of what people say goes right over my head

@John Bungen

Hey John, very nice score on that Speedster. Looks great!

1. Get one length of that rubber engine seal (Vw bus type) so that you can apply it all around the engine, not just the sides. Without that properly sealed your engine is still sucking in heat from the exhaust system.

2. It may be just the picture angle, but it looks to me that the pulley on the alternator is too large (diameter). You may need to replace that with a smaller diameter pulley. It may help to compare the diameter of a stock VW alternator/fan pulley to the one that's currently on your car. This would enable the crank pulley to spin the alternator pulley at a much faster rpm, thus pushing more cooling air to the engine cylinders.

3. Once you have sealed off the engine from the exhaust heat, get that pulley/cooling fan spinning faster try checking your temps. If that seems to help, then try re-opening the opening in the firewall and see if that also helps.

I'm sure you'll be able to sort it all out and then really start enjoying your new ride!

@MusbJim i just posted a bunch more photos above maybe you can see pulley better. i replied to danny p.

Photo 121700 shows that the doghouse tin is all in place. So that should be good, follow the rest of Jimmy's suggestions.

It looks like the sled tins are missing. Maybe not.  It is hard to tell. the photos are dark in that area.

The sled tins are definitely missing. They seem to lower the cylinder heads and oil temp by 10 degrees F in my experience. Any free temp lowering is a good thing.

Factory sled tins would definitely have to be modified and metal added/cut to work with those J-tubes and exhaust.

Sled tin and 2 pieces to rear missing -

Here's where two pieces go -

yes and the lower cylinder tins(?) I don't think we should be able to see unshrouded cooling fins in those pics from underneath; sled tins would attach to the front of the shroud at both sides of the engine and curl under, above the exhaust pipes, to funnel the air through those fins and out the back, away from the car as you drive.

@edsnova so these are the two sled tins? Do i need to have someone makes those like the sheetmetal up top i had made and screwed on?

Also needs the industrial tins.  I am not familiar with the CMC.  What is that metal plate on the fire wall in photo 20210818 (third row, 4th picture)?

@Bobby D i was told to block the air from that collared circle area and sides to force fan to pull air from truck lid area?

@John Bungen posted:

@Bobby D i was told to block the air from that collared circle area and sides to force fan to pull air from truck lid area?

I'm running a 2110cc with 150 hp and I don't have the opening in the firewall and my engine runs just fine. Others here have said you need it but yours is covered and I don't think it's necessary. I am running an external Setrab cooler with a fanpack and a deeper sump. I am also running with all of the tins in place. You can buy the tins but they MIGHT need some modification to fit just right.

John

My Beck speedster has one hole in the firewall directly across from the fan.  I don't know how everyone else's is setup.

John look go to https://www.awesomepowdercoat.com/.  This guys show all the Tins and how they should be installed. 

Besides the lack of any of the bottom sled tins, which it certainly needs, has anyone other than me noticed the lack of a thermostat bellows under the cylinders?  The stud is there, but no bellows.  For all we know, there might not be any air vanes inside of the fan shroud, OR they're in there and partially closed.  Either way, that, alone, will make it run hot

Jon wondered: "@edsnova so these are the two sled tins? Do i need to have someone makes those like the sheetmetal up top i had made and screwed on?"

No - They are available from places like CIP1 or Bugcity or Bugstuff in PA.   Look on their websites under Engine or Cooling or Engine Cooling.  Maybe someone could come up with a part number list for you?  They all just screw on with 6mm slotted/philips screws (get the screws at a local ACE Hardware store).  The commercial sled tin modifiers (Left and right) might be a little more difficult to find, but I think Gene Berg sells them.