valve shrouding

[Cyco]

Please post pics when it melts into the engine - I can GARRENTY that JB Weld does NOT have a glass transition temp capable of use close to a combustion chamber.

[Matra et Alpine]

BODY FILLER ? YOU SERIOUSLY WOULD PUT BODY FILLER NEAR A petroleum based gas/fluid ???

Thank you and good night hightower99

OK, folks if there is still anyone even thinking for 1/2 second of following this advice. There is the final nail in the coffin of his "expertise".
On Bondo's home page you can look up their MSDS handling sheets that gives the warnings. Their body filler is "incompatible with oxiders". All modern fuels have oxidiser additives to promote better burn and less nasty emissions !!!
So the MANUFACTURER says not to do it. ht. You're just making this up now and got caught with your pants down. BYeeeeeeeeeeeeee

[hightower99]

BODY FILLER ? YOU SERIOUSLY WOULD PUT BODY FILLER NEAR A petroleum based gas/fluid ???

no I wouldn't
the Bondo body filler is for the shaping process! I only ever suggested that JB weld be used and kept in the system. However Loctite's Metal set has about the same quality. I forgot to write "for shapeing" in the list header.

Please post pics when it melts into the engine - I can GARRENTY that JB Weld does NOT have a glass transition temp capable of use close to a combustion chamber.

I haven't heard of a single case of JB weld melting to glass state when used in intake porting... ever! And this porting technique doesn't have the epoxy too close to the combustion chamber anyways. on most cars it would be about a ½ inch away from the intake valve seat. By the way JB Weld is resistant up to 260 Deg Celsius and it will not melt to glass untill about 316 Deg Celsius (note: it takes 10 minutes of exposure to 316deg heat to melt it to glass)

[Cyco]

I haven't heard of a single case of JB weld melting to glass state when used in intake porting... ever!

If I was stupid enough to fill my engine ports with epoxy and it melted into the engine do you think I would run around and tell everyone?

nd this porting technique doesn't have the epoxy too close to the combustion chamber anyways. on most cars it would be about a ½ inch away from the intake valve seat.

That’s why you have previously recommended building up the back of the valve seat?

By the way JB Weld is resistant up to 260 Deg Celsius and it will not melt to glass untill about 316 Deg Celsius (note: it takes 10 minutes of exposure to 316deg heat to melt it to glass)

Again showing a lack of knowledge of material properties.

In this area (cut and paste from their site) I'd expect "resistant" to mean that the TTG is achieved here (260C) and that the 316C temp to indicate the decomposition point. That the site quotes nice round numbers also makes me very suspicious of these.

As with all Epoxies this can vary GREATLY depending on if a perfect combination is achieved and that it is perfectly mixed. You would want to test (prior to use) the effect (it can be pretty large, +-20C) of humidity at the time of mixing.

Please learn what marketing turns engineering descriptions into before you start quoting it as solid engineering, using terms it is now showing you don’t understand.

How do you propose that the epoxy used lasts a reasonable amount of time given the thermal stresses as the Aluminium head will have a thermal expansion of ~13% and the epoxy normally runs in the 0-2% range (not sure of the effect of the metal in JB Weld on expansion rates, or internal stresses created by theses thermal expansion issues?

I forgot to write "for shapeing" in the list header.

Please try and limit your forgetfulness - if anyone is willing to try this they need all the protection they can get.

[hightower99]

If I was stupid enough to fill my engine ports with epoxy and it melted into the engine do you think I would run around and tell everyone?

You mean if I followed Motoman's system and found that it didn't work... Me I would tell the tale, and I am pretty sure that anyone else would too. (Except for you of course)

That’s why you have previously recommended building up the back of the valve seat?

Umm what? I never recommended building up the back of the valve seat... The epoxy in the finished shaped piece will be about ½ inch from the valve seat...

Again showing a lack of knowledge of material properties.

How's that then?

In this area (cut and paste from their site) I'd expect "resistant" to mean that the TTG is achieved here (260C) and that the 316C temp to indicate the decomposition point. That the site quotes nice round numbers also makes me very suspicious of these.

Umm you don't need to expect anything it is all there 260C is what it can take indifinately without any damage to whatever you have used it for. (ie it does not turn to glass at this temperature) It does start turning to glass at 315.5555555556C (600F) and they note that it will take one package of it 10 minutes at that temperature to fully turn fluid and glass like!

As with all Epoxies this can vary GREATLY depending on if a perfect combination is achieved and that it is perfectly mixed. You would want to test (prior to use) the effect (it can be pretty large, +-20C) of humidity at the time of mixing.

Please learn what marketing turns engineering descriptions into before you start quoting it as solid engineering, using terms it is now showing you don’t understand.

How do you propose that the epoxy used lasts a reasonable amount of time given the thermal stresses as the Aluminium head will have a thermal expansion of ~13% and the epoxy normally runs in the 0-2% range (not sure of the effect of the metal in JB Weld on expansion rates, or internal stresses created by theses thermal expansion issues?Please try and limit your forgetfulness - if anyone is willing to try this they need all the protection they can get.

Perfect combination You mix it 1:1 it isn't hard to do that! and 20C at the high limits it says will not effect overall usefullness. I can only quote what the manufacturer says in there papers. And tell you that it has been used in this fashion many times without failure.

Cyco you must be smoking something because the thermal expansion of aluminium is (25 °C) 23.1 µm/(m·K) That is nowhere near 13% that is much smaller than 0.001% so I think the epoxy will do just fine!

[Cyco]

Again showing a lack of knowledge of material properties.

How's that then?

Right here in the following statement is a good example:

In this area (cut and paste from their site) I'd expect "resistant" to mean that the TTG is achieved here (260C) and that the 316C temp to indicate the decomposition point. That the site quotes nice round numbers also makes me very suspicious of these.

Umm you don't need to expect anything it is all there 260C is what it can take indifinately without any damage to whatever you have used it for. (ie it does not turn to glass at this temperature) It does start turning to glass at 315.5555555556C (600F) and they note that it will take one package of it 10 minutes at that temperature to fully turn fluid and glass like!

So a very brief vauge description (with very round numbers , published in F - not the conversion YOU have made into C to try and hide this) gives you absolute confidence? Yet another example of lack of knowledge, or is it a desire to decive?

Perfect combination You mix it 1:1 it isn't hard to do that!

hahahahahahahahahahahahahaha (sorry) That would yet another example, we are talking about squzing goop out a tube, and expecting to be able to squeeze EXACTLY the same amount (to the molecule - that is perfect combination) of a slightly runnier/thicker goop out of another tube. We must bow down to your far superiour knowledge.

the thermal expansion of aluminium is (25 °C) 23.1 µm/(m·K) That is nowhere near 13% that is much smaller than 0.001% so I think the epoxy will do just fine!

If you look at the number in imperial (13.1 µin/in-°F) its not a "technically correct" description, but one that has been used for a long time, again my apologies for this miss understanding, but please don't insinuate drug use where the issue is an unfimaliraty with the differing terminology (you are new to the area, and I out of it for a little while), is more likly the culprit.

At this point I will take my leave from this thread, there does not appear to be much more I can add here.

[johnnynumfiv]

Hightower, have you posted any pictures yet of the work that you've done and the dyno sheets?