Insulated Engine?
 

Since I now have a block heater in the truck, it got me thinking...How about insulating the engine compartment?

It doesn't really make sense to heat an engine that's just sort of out there in the cold, right?

My wife's Pontiac Sunfire has the same GM 2.2L engine in it, but her car warms up amazingly fast. I think part of the reason is how tightly the engine is crammed in that car.

In my truck, there is lots of spare room (so you could fit the 4.3L V6 in there..) and the truck is higher in the air than the car. In other words, lot of places for all the heat to get back out.

Has anyone added insulation to the engine compartment? (other than just a thin sheet on the underside of the hood) Would this help the block heater work better? Make the truck warm up faster? Any concerns about overheating?

I have heard that the Prius has a thermo-bottle that the engine coolant goes into, so the engine is warmer faster later when you go to restart again. Wouldn't insulating the engine do this as well?

Call me crazy, but I am wondering.

-Ben





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There is a thread that was started a while ago about this. Hood blanket... literally?

I'm currently working on sealing up my engine compartment(slowed down by the 1/2in of ice we got recently). I already put in a gasket around the hood itself. Which I've seen a decent improvement from that alone. So if you've got a garage unlike me, I say go for it :thumbup:

I found this stuff at lowes that might be worth looking at Reflectix 16" x 25' Foil Insulation they have it up to a 4' wide roll if you need it.

I did read the hood blanket thread. I thought that was on the right track.

I have a garage, but my wife's car is on the one side and the electric Geo Metro is on the other.

The truck has to sit out in the cold.

I like the idea of at least gasketing the hood. I hadn't thought of that.

I've used radiant barrier unsulation before, and that seems like a good material to start with for this application.

an engine doesnt just need more heat, it needs a very specific heat range. anything you can do to get the cooling system around 200-210 and keep it there is going to help the engine run well. Having too much heat will negatively affect performance well. In a perfect world, I think it would be nice to have the engine bay slightly sealed, with some fresh air flow to reduce moisture, the radiator/ac/oil coolers have their own entirely seperate in and out air flow, and the intake have a variable fresh outside air to warm behind the radiator air system.

I am working on that actually, using an electric acutated valve that opens to cold air only when above a certain TPS level (so that it gets power only when you need it, i.e. pressing hard on the gas pedal). All other times it will be sucking nearly 200 degree air straight from in between the headers.

(My car has a map sensor, and like in saturn vehicles, warm air intakes do wonders for map equipped vehicles- unlike the ones with maf sensors... dont ask me why this is though as I have noooo idea)

I would say you could use dynamat in the engine bay as it reflects heat away from the hood back to the engine as well as significantly reduces cabin noise and rattles... but its kinda expensive and kinda not what your looking for in this case.

Couldn't you kinda create a heat sink to block out cold air, keep the engine warm, but also prevent it from overheating? aluminum underpan perhaps?

I am thinking along the same lines. I don't think you want 365 days/yr insulated engine compartment. I like the heat sink that has been suggested, and the Prius thermos bottle.

Thinking out loud here;
There's a lot of surface area on an engine, that helps during the summer. I like the idea of leaving the engine compartment alone and using an auxilliary coolant vessel as your heat sink, the same way <as i understand it> that Toyota does with the Prius. But, add a plug-in feature that places the block heater in said insulated resevior. In operation, used with a timer and extension cord to the car in the driveway, connect 110v the heater in the evening and let the timer kick it on at 3am.

I am beginnig to think about an insulated resevior that has a built in, plug-in water heater like the Katz one installed on Johnny's Metro, only larger and better insulated. Maybe you build one by starting with a dry sump oil tank <racecar part> since they already have all the fitting bungs you'd ever need. All you'd need to do is insulate and mount it, then splice into your car's heater supply line.

1-2 gallon capacity should do it, heat the water to 130F overnight, and let the engine do the rest after it's started in the morning. If you stop for an hour, your insulated resevior, containing 200 degree water, will be your heat sink, even in the coldest of climates. For summer application, you may still want to plug in overnight.

As a 'bells and whistler' upgrade, you'd want the option to valve off the resevior, in the event the car gets parked away from 110v power, and you need faster warm up. Maybe after the engine is up to operating temp, you manually open the valve(s) and put the resevior back into the loop

This is what an Insight owner did for his engine.

Randall's Insight - MIMA Honda Insight Modified Integrated Motor Assist Tour De Sol

Scroll down to the Engine blanket stuff.

for most engines I would say this is over kill. but for the insight or other small engines it seems great. I have not done this my self no time/money.... But I do have a lower grill block and 75% of my radiator is covered with a piece for corroplast. with what I have done, when I coast with the engine on for about 1/4 of a mile the engine has dropped about 15-20f from 195ish. I have a lot more sealing work to do.

I think a lot of engines could benefit from this sort of thing in winter. I've noticed the Matrix holds a rock solid 188 degrees on the highway. Today I also noticed once I got off the highway and hit normal low speed roads, my engine temp dropped to 166! That's quite a drop off. Time to reinstall my lower grill block again! However, when summer rolls around I wouldn't want that extra insulation in there.

While it's running - sure.... But most of a car's life - the engine isn't running and from the instant the engine is killed to the instant it reaches ambient temperature - heat is being pulled away, lowering the temperature from optimal.


I don't think it's so much engine size... It's size v. load. A small engine maintaining high % power output is very well likely to get hotter than a large engine running at a low % power output. Granted, that's a hybrid application :p


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That said... of the yachts I've worked on AND seen the engine room.... All of them had blankets covering the engine, exhaust, coolant lines, heat exchangers, etc. The engineers on board say it's for sound dampening (still need ear protection while the engines are running), fire protection and insulation. These are by no means small engines either - we're talking 2+, SUV sized turbo diesels :thumbup: These blankets, on the outside, looked like woven fiber and were ~3/4" thick.