keeping fuel injections cooler

[Rob M.]

Re: keeping fuel injections cooler

I could use one too...

[Stuart F.]

Re: keeping fuel injections cooler

The aftermarket has that problem covered with manifolds like Edelbrock's "Air Gap", but that doesn't help us Corvette owners who don't want a hood bulge. That manifold is just high enough to present a clearance problem.

Yes, if no one else is marketing anything like that, it might be worthwhile. I'd buy one.

Did you drill and tap mounting holes? or is that a trade secret? Surely you didn't bolt through, did you?

Stu Fox

[Gary C.]

Re: keeping fuel injections cooler

Clem, you could write an article for the Restorer about your intake oil heat shield. Vinnie's always in need of good technical articles. Gary....

[Joel F.]

Re: keeping fuel injections cooler

Clem, you could write an article for the Restorer about your intake oil heat shield. Vinnie's always in need of good technical articles. Gary....

That is a great suggestion. Clem could probably keep Vinnie busy with several years worth of articles.

[Clem Z.]

Re: keeping fuel injections cooler

The aftermarket has that problem covered with manifolds like Edelbrock's "Air Gap", but that doesn't help us Corvette owners who don't want a hood bulge. That manifold is just high enough to present a clearance problem.

Yes, if no one else is marketing anything like that, it might be worthwhile. I'd buy one.

Did you drill and tap mounting holes? or is that a trade secret? Surely you didn't bolt through, did you?

Stu Fox

the manifold in the picture is a edelbrock performer intake and to do what is done there the heat riser crossover passage was milled off make a flat surface to mount the shield. on a FI manifold this area should already be flat and all that would be needed would be the plate,some spacer and some tapped holes. you can see in this picture how only 4 of the intake runners are in the area of the hot oil causing the fuel distribution probem.

[Bill M.]

Re: keeping fuel injections cooler

Here are the underside of an FI bed plate and a 340 intake .(I had to repair the 340 heat shield. I think it was riveted from the factory.)

[Stuart F.]

Re: keeping fuel injections cooler

Clem and Bill;

Thanks for posting the pictures. I'd never seen the bottom of a 340 hp manifold as mine has never been off. It appears about like I recall the old cast iron units looked, what with the rivets and all. It appears, Bill, that you remounted with bolts in place of the rivets.

Clem, I hope you didn't undo your safety wire job in order to post a photo of the underside of the Performer manifold w/o the heat shield. If you did, I appreciate your efforts to show us your mounting system.

Stu Fox

[John D.]

Re: keeping fuel injections cooler

Clem, Your idea is quite interesting. Lets discuss it over lunch soon. But I do think you need a lot more than the oil heat shield to help aleviate the problem.
Barry Holmes has a 62 FI Corvette and here is how he solved his perculation problems.
#1. One piece base gasket. Goes between the FI and the baseplate.
#2. Barry modified the repro fuel filter line that goes from the fuel pump on the engine to the FI unit. Seems that a typical repro line is not made correctly. He got the hot line up off the valve cover by doing this. Shortened the line where it goes into the fuel filter 90 degree fitting. I believe he took about 1/2" out of the line and then double flared it.(This number needs to be confirmed)
No more perc problems. Now I also suggest if you are not showing the car to insulate this supply line from the fuel pump as it really gets so hot you can't touch it.
The fuel is boiling even before it gets to the FI unit.
Another crutch is to bring some fresh air into the engine compartment. On a solid axle car her is what to do. The heater hose that comes from the rad. support has to be cut and a 12V motor put into this hose.
Then you direct the cool air under the FI unit. Controll the motor with a toggle switch in the car of course. You won't believe how great this works.
Also in 80 plus weather don't latch the hoods. Now if you FI is in an old hot rod with no hood then you don't need to do anything as the heat escapes.
The old guy on the west coast said to remove the hood and store it in the attic. Mr. Dennis Clark. End of problem.
When these cars were brand new they always had heat problems. But not near as severe as today.
Install an electric fan in front of the radiator. Install an electric fan under the hood.
Do something to get rid of the hot air.
Or scrap all of the above and do what I did on my 63 FI car called the LWC.
I just use 100LL and have no problems. I also have one of Tom DeWitt's fine radiators and a 180 degree therm and a Fred Olivia rebuilt clutch fan and whatever else it took.
Although I don't drive my car much I just love for it to sit and run for an hour with the hood closed. Then I reach in and turn the key off. I wait for about 10 minutes so the engine is really hot. Then I hop in the car and hold the pedal to the floor and turn the key and it fires right up and runs perfect. Try that with our pump gas. Never happen. JD

[Tyler T.]

Re: keeping fuel injections cooler

One way the NASCAR guys use to cool the top of the motor is to route oil to each spring. I think you can buy the valve covers with this mod. The decrease in temperature was pretty impressive.

http://www.stockcarracing.com/tipstricks/scrp_0502_stock_car_racing_valvespring/single_spring_design.html

Tyler

[Clem Z.]

Re: keeping fuel injections cooler

Clem and Bill;

Thanks for posting the pictures. I'd never seen the bottom of a 340 hp manifold as mine has never been off. It appears about like I recall the old cast iron units looked, what with the rivets and all. It appears, Bill, that you remounted with bolts in place of the rivets.

Clem, I hope you didn't undo your safety wire job in order to post a photo of the underside of the Performer manifold w/o the heat shield. If you did, I appreciate your efforts to show us your mounting system.

Stu Fox

no problem as i have 100s of feet of stainless steel safety wire and several pair of safety wiring pliers.

[Clem Z.]

Re: keeping fuel injections cooler

Clem, Your idea is quite interesting. Lets discuss it over lunch soon. But I do think you need a lot more than the oil heat shield to help aleviate the problem.
Barry Holmes has a 62 FI Corvette and here is how he solved his perculation problems.
#1. One piece base gasket. Goes between the FI and the baseplate.
#2. Barry modified the repro fuel filter line that goes from the fuel pump on the engine to the FI unit. Seems that a typical repro line is not made correctly. He got the hot line up off the valve cover by doing this. Shortened the line where it goes into the fuel filter 90 degree fitting. I believe he took about 1/2" out of the line and then double flared it.(This number needs to be confirmed)
No more perc problems. Now I also suggest if you are not showing the car to insulate this supply line from the fuel pump as it really gets so hot you can't touch it.
The fuel is boiling even before it gets to the FI unit.
Another crutch is to bring some fresh air into the engine compartment. On a solid axle car her is what to do. The heater hose that comes from the rad. support has to be cut and a 12V motor put into this hose.
Then you direct the cool air under the FI unit. Controll the motor with a toggle switch in the car of course. You won't believe how great this works.
Also in 80 plus weather don't latch the hoods. Now if you FI is in an old hot rod with no hood then you don't need to do anything as the heat escapes.
The old guy on the west coast said to remove the hood and store it in the attic. Mr. Dennis Clark. End of problem.
When these cars were brand new they always had heat problems. But not near as severe as today.
Install an electric fan in front of the radiator. Install an electric fan under the hood.
Do something to get rid of the hot air.
Or scrap all of the above and do what I did on my 63 FI car called the LWC.
I just use 100LL and have no problems. I also have one of Tom DeWitt's fine radiators and a 180 degree therm and a Fred Olivia rebuilt clutch fan and whatever else it took.
Although I don't drive my car much I just love for it to sit and run for an hour with the hood closed. Then I reach in and turn the key off. I wait for about 10 minutes so the engine is really hot. Then I hop in the car and hold the pedal to the floor and turn the key and it fires right up and runs perfect. Try that with our pump gas. Never happen. JD

i have noticed on a lot of chevy engines the fuel line from the fuel pump to the carb,never looked at a FI engine for 40 years, is touching the bottom rad hose which adds heat to the fuel especially at idle when the fuel is flowing very slowly thru the line

[Joe C.]

Re: keeping fuel injections cooler

after reading the FI article in "the corvette restorer" and the problem heat causes the FI unit and the recommendation of using a 160 degree water thermostat why not install a oil heat shield under the FI base plate to keep the hot oil,200+ degrees, off of the base plate. this heat is transferred to the whole FI unit because of the aluminum construction. this is what i do with intake manifolds to keep the hot oil off the bottom of the manifold and causing unequal fuel distribution. JMHO

Clem,

Great minds think alike! Initially, the splash shield sounds like a good idea, and I've thought about doing that, too, BUT. The only reason that the splash shield is installed, is to prevent the oil from "coking" when it contacts the area near the exhaust crossover port. That is why the shield is ONLY installed in intake manifolds employing an exhaust crossover port. If the manifold (such as the Rochester plenum) has no exhaust crossover, then the splash shield is unnecessary, and so, it was not used for those applications. It is not used on aftermarket "high performance" manifolds without exhaust heat. It is "optional" and can be retrofitted to most GMPP intakes with exhaust crossover ports, however, most engine builders who use these in "high performance" or mild racing applications, block the crossover port. It was not included on many of the later style 3972116 Service Replacement Z28/LT1 intakes.

Insofar as keeping the manifold cooler, it is of no benefit, because the aluminum is in full contact with the heads and is warmed through direct conduction and convection of the hot gas within the lifter valley. One effective method of keeping the intake manifold cooler (in addition to blocking the exhaust crossover port) is to use an "air gap" design mainfold. Ford's "Y" block and many Pontiac engines were employing this design since the 1950's. Another effective method, and one which is employed by many of the hopped-up "ricer" 4 and 6 bangers, is to employ insulating intake manifold gaskets, which provides a barrier to much of the conduction from the head(s).

Joe

[Bill M.]

Re: keeping fuel injections cooler

Clem and Bill;

It appears, Bill, that you remounted with bolts in place of the rivets.

Stu Fox

Hi Stu:

I did replace the "rivets" (I called them rivets, but they are not really a rivet. It's not peened over. It's more a staking pin...?) with bolts (in the 60s, probably with a lot of help from my dad!). I remember there was a leak at one of the locations. I can see sealer where bolt holes have broken into two intake ports. The repair probably made the hole deeper, so there may have only been one leak before I "fixed" it!

Bill

[Clem Z.]

Re: keeping fuel injections cooler

Clem,

Great minds think alike! Initially, the splash shield sounds like a good idea, and I've thought about doing that, too, BUT. The only reason that the splash shield is installed, is to prevent the oil from "coking" when it contacts the area near the exhaust crossover port. That is why the shield is ONLY installed in intake manifolds employing an exhaust crossover port. If the manifold (such as the Rochester plenum) has no exhaust crossover, then the splash shield is unnecessary, and so, it was not used for those applications. It is not used on aftermarket "high performance" manifolds without exhaust heat. It is "optional" and can be retrofitted to most GMPP intakes with exhaust crossover ports, however, most engine builders who use these in "high performance" or mild racing applications, block the crossover port. It was not included on many of the later style 3972116 Service Replacement Z28/LT1 intakes.

Insofar as keeping the manifold cooler, it is of no benefit, because the aluminum is in full contact with the heads and is warmed through direct conduction and convection of the hot gas within the lifter valley. One effective method of keeping the intake manifold cooler (in addition to blocking the exhaust crossover port) is to use an "air gap" design mainfold. Ford's "Y" block and many Pontiac engines were employing this design since the 1950's. Another effective method, and one which is employed by many of the hopped-up "ricer" 4 and 6 bangers, is to employ insulating intake manifold gaskets, which provides a barrier to much of the conduction from the head(s).

Joe

the engine temp is about 160/180 degrees BUT the oil being splashed onto the bottom of the intake is over 200 degrees. this is why GM has the oil splash shield# 12555320 for BBC that was use with a intake manifold and a carb.

[Michael H.]

Re: keeping fuel injections cooler

the engine temp is about 160/180 degrees BUT the oil being splashed onto the bottom of the intake is over 200 degrees. this is why GM has the oil splash shield# 12555320 for BBC that was use with a intake manifold and a carb.

Clem is right on, as usual. Keeping the hot oil off the bottom of the manifold is important. The oil splash shield that GM designed for big blocks way back in the mid 60's works. Big blocks splash a LOT more oil around the valley than small blocks but they all do it.
The trick is to keep the lower section of the splash shield far away from the manifold as possible, yet still function as a shield to make sure the oil doesn't get by on the sides.

The cyl heads are always hotter than the temp of the coolant that is exiting at the front of the manifold. The coolant is only warmed to the temp of the surface of the cast iron. Not the core. The core of the cast iron is always 10* to 20* hotter in most areas and a LOT hotter around the exhaust port. That heat travels by convection to other areas of the casting.
That's another reason why cooling systems often boil AFTER the engine is shut off. The coolant temp immediately begins to rise to the core temp of the casting when it stops flowing.
That heat also travels from the cyl head to to the intake manifold after an engine is shut down.