355 Inner CV boot deterioration, swelling, deformation and cracking problem? .. Nope!

Had a big block Vette. No heat shield on starter; starter failed after engine got hot. Installed stainless steel heat shield, starter never failed thereafter. Not this part, but anecdotal evidence that heat kills and stainless steel saves. I need no further data than this real life experience.

Good one goth!

 

Hey Goth,
Will you be posting the heat measurements info?

 

Excellent documentation Goth.

That should keep the naysayers at bay. Excellent work and documentation.

 

First, let me say I appreciate your efforts in performing these tests. However, the car is not moving during the tests. Engine idling. I'd like to see T3 while the car is actually being driven.

I have no issue with what you have done. For a static test they are what I would have expected. I never argued that the shields would not be effective at reducing radiant heat to the boot. But, as I did post, that is only 1/2 the story. The important effects of cooling air flowing over the boot due to the motion of the car are omitted and will be considerably greater with the OEM shield.

In summary, your posted results show that the shields are effective at reducing radiant heat transfer but they are not conclusive with regard to what the boot temperature would be while the car is being driven. They may well prove to be superior under those conditions as well, but that conclusion can not be made from these tests.

 

John, heat is your enemy. Anything that deflects or reflects heat is your friend. When the car is moving, air is circulating around the engine bay. This is not so much where your 355 heat problems lie. It's when you are idling and at rest after a drive. Radiant heat from an engine that has been driven with the slightest gusto is not only higher for this model, but dissipates slowly, much slower than a 348 or anything without a gothspeed muffler system. Get on board the train buddy; everyone else is.

 

I'm not disagreeing with the idea that heat is the enemy. But the degradation of the boots is over time; an accumulated effect from both when the car is stationary and when it is moving. So what happens when the car is moving is also important. None of the data demonstrate what temperatures the boots see while the car is moving with either shield installed which hopefully how most of their time is spent. It may be that what happens when the car is stationary, even for short periods of time (at stop lights, etc.) may be the dominate contributing factor. I don't know one way or the other. And I can not venture a guess w/o knowing what happens when the car is moving. Since I'm interested in knowing that, I have decided to take my own data for the OEM shields and for the OEM shield with the aluminum cover which I fabricated. Once I see those results I may fabricate something similar to Goth's shields and see what they do. It's the price you pay when you're are a retired research scientist and of a curious nature.

Data logger on the way. Battery-Powered Remote Thermocouple Data Logger - Measurement Computing

Goth, if you want unbiased, independent verification of your data, as well as data while the car is in motion on a given route, send me a sample for one side.


[edit] One other thing I want to point out is that there is another reason why the temperature while moving is important to know. If you examine Goth's temperature plots you will see that as soon as the engine is shut off the boots start to cool. So how hot the boots will get, say when you come to a stop light for 20 sec will depend on what temperature they were at when you came to a stop. And after a drive, when you shut the engine off, it appears that in neither case, OEM or Goth shields, dose the boot temperature continue to rise. In fact, if you examine the expanded plots, with the OEM shields the boots start to cool off immediately after engine shut off where as with the Goth shields they seem to remain at an elevated temperature. This could certainly be an indication that after shut off the Goth shields restrict air circulation and slow the cool down process. You can counter argue that the boots weren't as hot at shut down with the Goth boots installed. Valid point, if you let you car idle for 55 minutes. But the question I would ask is, if the boots were at the same temperature when the engine was shut down which shields would allow the boots to cool faster? Since in most cases the boot temperature at shut down will be after driving it is important to know the variation of boot temperature with the car in motion.

The point I am making here is that when you look at data you have to understand what it represents and how it relates to real world applications. Letting a car idle for 55 minutes motionless does not represent anything close to real world conditions. But what this data does show is that under such conditions the Goth shields keep the boot temperature lower while the engine is idling for an extended period, but also seem to prevent the boots from cooling as fast after shut down.

 

Has anyone tried wrapping the exhaust where it comes close to CV boot to prevent a hot spot? My exhaust is about an inch away from boot.

Other option is to put a shield right on exhaust pipe in that area.

 

Has anyone tried installing these on a 95? I see them being installed on a 96+ back in post 39, but on a 95 there is no way they are going in from the top. The Y pipe, and perhaps even the header flanges for the Y pipe would be in the way. Very tight in there on a 95. Even the OEM shields need to be shifted this way and that to get them in. Maybe get them in by placing them over the axel and sliding them towards the trans.

 

I don't know the exact size of your shields but looking at the car I don't see how one would be able to get the shield in there from the top. There is just no room to put it in from the top. The distance between the back side of the engine and the Y-pipe flange on the header is less then the diameter of the CV boot and the shield must be wider than that (see picture). And the shield has to be centered to drop over the axial. I have no doubt that they will fit, though tightly, once in there, but getting them in there w/o removing Y pipe and header is going to be a challenge, Even if you take the mounting bracket off first. I think the best bet may be, as I said, going in from the wheel well, getting the shield over the axial and then sliding it under the header and Y pipe and over the mounting bracket. Obviously, only a factor for 95s.
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I bought the shields for my 96 355. Very nice looking product, with great instructions. They have been sitting on my bench for a couple of weeks.

I took my car out today for a much needed spin. It was a very hot day. When I parked the car, I opened the lid and noticed a funny rubber smell. After a close look I noticed the driver side exhaust clamp (pre cat) was right next to the boot, almost touching it. I poured some water on the boot and decided to install the new shields. My boots are brand new. Tubi headers, OE CATS, and Tubi exhaust.

Bottom line, that clamp can rotate and can be very close to the CV boot. I installed the Goth shields, and adjusted the clamps for maximum clearance. Glad I bought the shields.

Oh, did I mention what a great drive I had today. I love this car.

Thanks Goth.

 

Installed mine yesterday on a 98. Very simple.

 

John has a valid point here. After installing my modified (longer) fiberglass shields I found they were time consuming to install on a 1995 due to the crossover secondary cats.
I think with the more robust Goth metallic shields one would have to slide the shields down the axle shaft (with the mounting bracket installed on the transaxle)....looks dooable though.
We'll need someone with a 1995 to share.

 

Thanks for posting the thermal results.....the Goth shields look very promising

 

I don't want to give anything away, but there are more data coming.

Bottom line, more evidence that these things work.

 

There is little doubt in my mind that the Goth shields will help keep heat away from the outer edges of the boot, the area closest to the exhaust pipe.

 

Sir, May I please purchase a pair of your SS CV heat shields? Tom Watkins 801-278-1913 (please leave message). Thank you. TW

 

^ They are in stock and available for immediate shipment here:

Ferrari Parts : GS355CV F355 CV BOOT SHIELD SET : Ricambi America

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Geez Goth, I thought you'd publish the findings here already.

Here's the crux - the temperature in your 355 engine bay climbs quickly as the engine comes to temperature. Everything gets hot, especially stuff closer to the exhaust system, notably the cats. Conductive heat is what it is - hard to deflect except through insulation and heat sinks to radiate it out to coolers. Not what we are dealing with here.

You have substantial radiant heat from the cats that the stock shields just don't deflect. In fact, I think they are about worthless given they don't protect from radiant heat sourced from the hottest part, your cats.

Your greatest enemy is radiant heat while the car is at rest or traveling at low speeds - hence, stop and go traffic, low speed travel and post drive cool down. While driving at speed, cooling air circulates within the engine bay pretty well, keeping temps manageable. Once you slow down or stop, it is another story.

The Goth shields are proven to protect your boots from this radiant heat when they are most vulnerable. The evidence is so compelling, I can't believe the factory didn't figure this out on their own. On the other hand, it meant more maintenance income for them.