Operation TLC

Gladiator · Postby **Gladiator** » Tue Dec 09, 2014 7:56 pm

ndragun wrote:Sooooo... bit of a digression this evening. For those out there that think HVAC is unwanted mass on their "track cars", look away now...

After 20 years of service, the foam used in all of the HVAC baffle plates has pretty much turned to dust with air exposure and needs to be replaced. Over time the foam deteriorates - and then when you pull the dash out and happen to touch it - it all goes powdery and crumbs off. Even if you haven't touched it or pulled the dash - you might get hit in the face on occasion by an errant piece of dislodged foam through the vent system...

This is what the foam looked like in my HVAC system... when touched it goes to moosh... The foam pictured here was stuck to the blower baffle plate. This is the plate that determines whether or not you get air from the outside world, or re-circ'ed from the cabin. If you have AC, the air from this baffle plate travels straight on to the AC expander and gunks it up. If not then it goes through to the heater and gunks that up, or hits you in the face. There are also 3 baffle plates in the heater housing that have similar foams. They all turn to dust over time.

SO - what you need is some contact adhesive, IPA (isopropyl alcohol), some foam sheet (Clark Rubber - 5mm foam sheeting) and some adhesive weather strip.

Scrape all the old powdery foam off the baffle plates, scrub the shiz out of it, then clean with IPA. After that, cut the foam sheet to size, spray it and the baffle plate with contact adhesive... Have a few swigs of your favourite beer while you wait for the contact glue to touch dry, then stick that mother flipper down. Cut the excess.

Repeat for every bit of foam throughout the HVAC system.
Its also useful to grease up the linkages on the sides of the heater housing and blower fan housing before putting it all back together.

Over the many many years, my car has been parked under many a dirty tree and has travelled many a dusty kilometre. The HVAC system gets DIRTY. Clean it while you're in there wiring a brand new ECU.

So much attention to detail! I only wish I had your patience & dedication. Love your work.

Magpie · Postby **Magpie** » Tue Dec 09, 2014 8:15 pm

Since your set up is identical to mine you may want to keep a close eye on the Pipercross filter as any backfire through the ITB's could cause fine particles to enter the combustion chamber and damage valves. This is the opinion of the head builder of my engine following a loss of compression.

Whilst your engine build may not be the same, the effects of fine particles on valves will be. Gslender will not suffer this fate as he has an airbox and the filter is a fair distance away. An alternative could be to use an oiled filter/socks.

Maybe other ITB owners could provide some feedback on filter damage?

gslender · Postby **gslender** » Tue Dec 09, 2014 8:18 pm

I can't see how oil socks would be better, if anything (assuming any filter close to the trumpet would equally be a problem) socks would therefore be worse. The piper dome filter would be better than sock in that regard. The only other scenario is that the piper filter material is crap, but that's odd given you'd think piper wouldn't use anything unsuitable?

ndragun · Postby **ndragun** » Tue Dec 09, 2014 10:08 pm

Not quite following what you're saying - do you mean you think the filter foam itself is breaking up and being sucked down the intake? Can you see any evidence of that when you take the filter off? And more to the point, what shape are the trumpets and backing plate in? Any obvious signs of dirt, dust, grit, grime, whatever?

Magpie · Postby **Magpie** » Tue Dec 09, 2014 10:39 pm

Yes it would appear that the inside of the filter is breaking down from the flame front comming back up through the ITB's (backfire). The evidence is carbon on the inside of the air filter. Essentially there is no dust/particles left because it is all being sucked back into the combustion chamber.

Again this is just a suggestion to keep an eye on the filter. The backfire is more than likely a result of my tune and the way it is dríven so it may not be a concern for your build.

mrpham is about to do a head swap and will let me know the condition of his valves. Whilst mrpham is not using Jenvey's/Pipercross it may provide some information.

Postby **mrpham** » Tue Dec 09, 2014 10:55 pm

Magpie wrote:Yes it would appear that the inside of the filter is breaking down from the flame front comming back up through the ITB's (backfire). The evidence is carbon on the inside of the air filter. Essentially there is no dust/particles left because it is all being sucked back into the combustion chamber.

Again this is just a suggestion to keep an eye on the filter. The backfire is more than likely a result of my tune and the way it is dríven so it may not be a concern for your build.

mrpham is about to do a head swap and will let me know the condition of his valves. Whilst mrpham is not using Jenvey's/Pipercross it may provide some information.

Will definitely keep you guys posted, I haven't really experienced backfire through the ITBs though.

There was one instance where it did backfire and one of the UNI Filters melted. I hurt my ankle pretty bad so I had a friend reverse my car to shuffle my other cars around, well she stalled it a million times. So there must have been an excess of fuel and it backfired

ndragun · Postby **ndragun** » Tue Dec 09, 2014 11:49 pm

Magpie wrote:Essentially there is no dust/particles left because it is all being sucked back into the combustion chamber.

Anything come away from the filter foam though? Does it look like its broken down at all?

Are we talking about a 'cause', or an 'effect' here though really? Honestly, I think worrying about burnt filter foam in this case is like worrying about your hairdo after your heads been chopped off. There are more serious issues here.

You shouldn't be backfiring up past the throttle plates in the first place surely? To say that the backfiring was fine, but burnt foam is what has caused valve damage sounds a bit bizarro-world to me.

That's not to say that your advice isn't warranted Magpie. Will definitely be a good idea to keep an eye on it all while we're tuning. IF IT EVER COMES TO THAT. My third child is due in 3 weeks. I may not even get this thing finished :lol:

ndragun · Postby **ndragun** » Wed Dec 10, 2014 12:01 am

mrpham wrote:There was one instance where it did backfire and one of the UNI Filters melted. I hurt my ankle pretty bad so I had a friend reverse my car to shuffle my other cars around, well she stalled it a million times. So there must have been an excess of fuel and it backfired

That is funny...
Good to meet you yesterday BTW John and kudos yet again on your build and wiring in particular. I was thinking in traffic on the way home that your car for some reason looked like a 75% scale model of mine.... I think I'm now used to it being up on jacks and in pieces. Everything looks so much bigger disassembled.

Didn't get hailed on in the van though unfortunately.

Magpie · Postby **Magpie** » Wed Dec 10, 2014 4:58 am

Ndragun appologies for my comments I will confine them to my build thread.

ndragun · Postby **ndragun** » Wed Dec 10, 2014 8:46 am

Magpie wrote:Ndragun appologies for my comments I will confine them to my build thread.

Not at all Magpie - don't be silly! Like I said, I definitely appreciate the comments.

Maybe we take it over to your build thread anyway - since I'm curious of the outcome. But just remember mate - if I come across critical - I'm critical of the theory itself, not the person with the theory :wink:

ndragun · Postby **ndragun** » Wed Dec 10, 2014 8:57 am

PS - see if you can get a photo of the inside of the filter and post it up - I'm curious to see what you're describing.

ndragun · Postby **ndragun** » Wed Dec 10, 2014 12:07 pm

(http://mx5cartalk.com/forum/viewtopic.php?f=57&t=51400&p=825663#p825663)

mrpham wrote:Is your gearbox bolted up to the PPF? If the engine/transmission is "sagging" it may reduce the clearance. Maybe you can loosen the PPF bolts at the gearbox and jack up transmission and re-tighten. Could gain a bit more clearance.

I get what you're saying and will mess with the PPF, but honestly, its probably not going to be enough. Look at the hole in the plate and how much more I need to go toward the firewall just to get it to line up. I even considered packing the engine mounts a bit to raise it up and sideways - but its really not the proper answer...

It's a good point though John. I'll bolt up those frame rails, get a bit of rigidity in there and shove the PPF around to see how much everything moves. Bear in mind, mine is still up on jacks and is missing all the suspension, sway bars, wheels, dash, seats, body panels, fluids... Once all that weight goes back in there, its surprising how much everything changes shape.

Postby **mrpham** » Wed Dec 10, 2014 12:14 pm

All good man, see how you go.

When I jacked my gearbox up and re-did the PPF bolts, it gave me so much more room behind the head. Can easily do a coolant re-route with all the extra room. But on my friends car it was a huge pain in the ass.