Bodywork, Paint, Interior, Trim, & Wiring

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Scott68B
Scott Costanzo
Columbus, Ohio
(548 posts)

Registered:
10/25/2007 11:30AM

Main British Car:
1968 MGB GM 5.3 LS4 V8

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Fiberglass & Engine Bay Heat
Posted by: Scott68B
Date: September 01, 2010 07:20AM

Does anyone have any negative experiences using fiberglass components in an engine bay? I know nothing about fiberglass at this point but I'm reading that the heat resistance of polyester resin based products is somewhere between 170-210 F. I would guess it wouldn't be unusual to exceed this range on a warm day. Any insight would be welcome.

Thanks!

-- Scott


Bill Young
Bill Young
Kansas City, MO
(1337 posts)

Registered:
10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

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Re: Fiberglass & Engine Bay Heat
Posted by: Bill Young
Date: September 01, 2010 10:05AM

Scott, that sounds a bit low, most resins cure at almost 300 degrees F, I'd think they could withstand well over 210F in use. Everything around the engine in my old Corvette was fiberglass and it never showed any sign of damage from the heat. Some of the "factory" muscle cars in the 70s had fiberglass hoods as well. If you keep it at least an inch away from the exhaust manifold I wouldn't think you would have any problem. You could run it a bit closer if you use some sort of heat barrier or reflector between the two. A piece of aluminum with a 1/2" air gap between it and the body really will help reduce radiant heat transfer.


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1104 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

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Re: Fiberglass & Engine Bay Heat
Posted by: ex-tyke
Date: September 01, 2010 10:46AM

My fan shroud is made of good old fashioned matt & resin and seems to be holding up just fine......operating in 200F environments isn't a problem.


Preform Resources
Dave Craddock
Redford,Michigan
(359 posts)

Registered:
12/20/2008 05:46PM

Main British Car:
72 MGB V6 3.4

Re: Fiberglass & Engine Bay Heat
Posted by: Preform Resources
Date: September 01, 2010 04:48PM

Scott, The heat distortion for poly parts depends on the type of poly resin used , GP or general purpose resins are in the 160 f range, Isopthalics (the type we use) are in the 225f range more than adequate for the average situation. Now if you want to get really trick, you could use epoxy , however the same can be said for lower grades of epoxy, which are dimensionally stable
but have poor heat distortion, but a good grade of room temp cure epoxy will easily go 300/350 f and makes a much stiffer laminate, the down side of epoxy lams is that the resin is 3 to 4 times more than poly , the reinforcement ( e-glass/carbon/kevlar
etc.) costs more and the whole process is more labor intensive ,hence the higher end price. Basically as Bill said, as long as your headers are few inches away you should have no problem. good luck.
Dave Craddock


Scott68B
Scott Costanzo
Columbus, Ohio
(548 posts)

Registered:
10/25/2007 11:30AM

Main British Car:
1968 MGB GM 5.3 LS4 V8

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Re: Fiberglass & Engine Bay Heat
Posted by: Scott68B
Date: September 02, 2010 06:34AM

Everyone, thanks for the responses, it's a big help.

Dave, thank you for the detailed response, exactly what I was looking for.

Graham, a radiator shroud is what I'm going to attempt to fabricate.

Regards

-- Scott


Preform Resources
Dave Craddock
Redford,Michigan
(359 posts)

Registered:
12/20/2008 05:46PM

Main British Car:
72 MGB V6 3.4

Re: Fiberglass & Engine Bay Heat
Posted by: Preform Resources
Date: September 02, 2010 03:07PM

Scott, a good way to make a rad shroud of fiberglass, is to make it out of mat board(as in picture matting)) ,you can tape it together try to keep it neat looking, then take some johnsons paste wax(or minwax) as in for waxing wood surfaces, wax few coats letting it soak in a little before buffing off the eccess( you can coat with PVA mold release if you have it also) then layup your fiberglass over the cardboard mockup, let it go off thoroughly, then peel the cardboard out from the inside trim as necc. and sand any ugly edges , drill the mount holes and paint. If you want it smooth on the outside do the above on the female side
of the model instead, maybe not the prettiest of parts but should be effective.
Dave Craddock


Scott68B
Scott Costanzo
Columbus, Ohio
(548 posts)

Registered:
10/25/2007 11:30AM

Main British Car:
1968 MGB GM 5.3 LS4 V8

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Re: Fiberglass & Engine Bay Heat
Posted by: Scott68B
Date: September 03, 2010 06:26AM

Dave,

Wow, excellent advice! I really appreciate it! Thank you!!

-- Scott



ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1104 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

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Re: Fiberglass & Engine Bay Heat
Posted by: ex-tyke
Date: September 03, 2010 09:07AM

Using Dave's method (rather than a hard mold, like wood) allows you to design in shroud surfaces that otherwise would result in a part/mold lock issue using conventional mold tooling...and you don't have to worry about a 3 degree taper on the release surfaces.
The down side is that it's good for a one shot part before the mold is destroyed......that's a good trade off for a one off part!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5920 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: Fiberglass & Engine Bay Heat
Posted by: BlownMGB-V8
Date: September 03, 2010 09:28PM

Sometimes sheet brass works pretty good too and it can be buffed out when you finish. Doesn't have to be one piece either. I made a very nice 4 piece shroud that went together with stainless button head capscrews.

JB


kstevusa
kelly stevenson
Southern Middle Tennessee
(943 posts)

Registered:
10/25/2007 09:37AM

Main British Car:
2003 Jaguar XK8 Coupe 4.2L DOHC/ VVT / 6sp. AT

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Re: Fiberglass & Engine Bay Heat
Posted by: kstevusa
Date: September 11, 2010 12:04PM

Scott, I've had my F/G hood installed since 5/05 and driven about 30k miles. The temp surely has been over 225 degrees inside and over 110 on outside. This hood was 1 of 3 original modified MGC types made in Fla. when they became available. There has been no degradation and it is still solid. Don't think there should be a problem with a shroud. Now for the Dickel cupholder! NOTE: only consume Dickel when you return to the Room! Merv will use it for Tim Horton's coffee. Ha


tr8todd
Todd Kishbach

(372 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: Fiberglass & Engine Bay Heat
Posted by: tr8todd
Date: September 13, 2010 07:27AM

I have ultra thin fiberglass hoods on my race cars and have had no issues. It gets real hot under there. Now an engine fire, that's a different story.


Scott68B
Scott Costanzo
Columbus, Ohio
(548 posts)

Registered:
10/25/2007 11:30AM

Main British Car:
1968 MGB GM 5.3 LS4 V8

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Re: Fiberglass & Engine Bay Heat
Posted by: Scott68B
Date: September 13, 2010 07:09PM

Thanks for the feedback Kelly & Todd, I appreciate it.

Kelly, I shared the last sliver of your Dickel with my neighbor John. He really like it!

-- Scott


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