Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: J. Russo on September 14, 2023, 09:08:15 AM

Title: 1941 Under Hood Insulation
Post by: J. Russo on September 14, 2023, 09:08:15 AM
I'm considering installing insulation under the hood of my 1941 Series 63. I have a product called Dynaliner from Dynamat that I have left over from insulating the floor.

My hood gets pretty hot and has no insulation. I haven't found in the judging or authenticity manuals if insulation was ever installed in these models.

Does anyone know if adding insulation under the hood is an issue with judging where it would result in a deduction of points?

Thanks in advance.
Title: Re: 1941 Under Hood Insulation
Post by: Paul Tesone on September 14, 2023, 10:44:30 PM
Can't answer the judging question , but I'm wondering if hood insulation would hinder dissipation of heat from the engine bay and contribute to "heat soak " - something so often experienced in the pre war Caddys . Paul Tesone CLC #6876 .
Title: Re: 1941 Under Hood Insulation
Post by: Jeff Hansen on September 14, 2023, 11:03:52 PM
John,

To my knowledge, there was never any insulation on the underside of the hood, the inner fenders, or the engine side of the firewall in 1941.  You don't see it mentioned in the authenticity or judging manuals because it was never installed at the factory.  There was a type of insulation installed on the interior side of the firewall to keep heat out of the passenger compartment.

Adding insulation under the hood might help with your heat issue on the hood, but Paul has a good point about heat dissipation - you don't want to hold engine heat in on these cars.

A few other things to consider:


My two cents anyway.

HTH,
Jeff
Title: Re: 1941 Under Hood Insulation
Post by: harry s on September 15, 2023, 10:18:06 AM
Like Jeff I'm not aware of any factory under hood insulation on '41s. I have seen some with undercoating to include my '41 67 Series and '48 conv. I'm guessing this would have been done at the dealer along with chassis undercoating.    Harry
Title: Re: 1941 Under Hood Insulation
Post by: J. Russo on September 16, 2023, 08:31:49 AM
Thank you for the input and expressing your concerns. I'll hold off from doing this.
Title: Re: 1941 Under Hood Insulation
Post by: LaSalle5019 on September 21, 2023, 11:27:59 AM
Hood insulation was only added to reduce engine noise. Both the previous points about holding in heat and not enough spring are good ones.
Title: Re: 1941 Under Hood Insulation
Post by: Whit Otis, 1188 on October 15, 2023, 05:59:25 PM
The 1940 Custom 60 Special LP Fisher car had undercoating on the bottom side of the hood.  This car was presented as all original, however a number of items were not.  That said, I personally examined this car on two occasions and I would say that the undercoating did look to be original given the look of it and the careful application of it.  Attaching picture with a partial view of the underside of hood.  Since this was a one off custom with chopped top, leather padded roof, extended chassis, etc., I would guess it unlikely a dealer would have done the undercoating since it was probably delivered from Fleetwood directly to LP Fisher.

Whit Otis

Title: Re: 1941 Under Hood Insulation
Post by: jwwseville60 on October 19, 2023, 09:13:19 AM
There are a number of high heat reflective aerospace materials out there.
We used one for my 63, but it was all custom so originality was never there.
If I hear you right, yours was custom as well.
I believe you can paint this material too.

My 1947 flathead v8 runs hot as designed.
I would worry about reflecting heat back down onto it.