Anyone With Epoxy Experience?
08-19-2003, 08:23 AM
#1
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Join Date: Jul 2001
Location: S. Florida
Posts: 629
I've ordered a brand of epoxy per Pineapple's recommendation to fix a small porous area in the bottom of one of my primary intake runners that I uncovered while porting them out. I'd buy another plate but it's a Cosmo plate and I can't locate one in good condition on short notice. The stuff is relatively expensive for glue ($50 plus shipping) but is supposedly bulletproof (needs to be BURNED off to get it out).
Because I don't have a real hole per se, it's going to make it sort of tough. Naturally my biggest concern is having it come undone and flying into the engine. Obviously cleanliness is essential but I'm not too sure what to clean the plate with yet. If I can reach the spot through the coolant passage, I may do it on that side (but it's unlikely).
Any pointers greatly appreciated.
Because I don't have a real hole per se, it's going to make it sort of tough. Naturally my biggest concern is having it come undone and flying into the engine. Obviously cleanliness is essential but I'm not too sure what to clean the plate with yet. If I can reach the spot through the coolant passage, I may do it on that side (but it's unlikely).
Any pointers greatly appreciated.
08-19-2003, 08:31 AM
#2
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Join Date: Jan 2003
Location: Perth, Western Australia
Posts: 267
Look at your other thread re welding!
If you go the epoxy route, use a cleaner which is pure solvent as some thinners leave a residue. Benzene, acetone or similar might work- the same as for cleaning oil soaked aluminium prior to tig welding.
So what type of epoxy are you using? Devcon is the usual for rotaries...
If you go the epoxy route, use a cleaner which is pure solvent as some thinners leave a residue. Benzene, acetone or similar might work- the same as for cleaning oil soaked aluminium prior to tig welding.
So what type of epoxy are you using? Devcon is the usual for rotaries...
08-19-2003, 10:59 AM
#3
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Join Date: Sep 2002
Location: Maryland
Posts: 3,867
I talked with Judge Ito about this. He informed me that he likes to epoxy the back side of the ports, and then port them, on some motors. When he starts to see the epoxy thats when he stops porting. He said he's never had a problem with it.
So if its good enough for him...its good enough for me
So if its good enough for him...its good enough for me
08-19-2003, 03:47 PM
#7
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I'm using something called Resinlab EP961 from Ellsowrth Adhesives (www.ellsworth.com). 92% part B w/100% part A in ratio. Used to be called Plastic Mastic.
Just to post in this link concerning welding, can't get at the back side of the port to weld it up. And from what I hear, you can't "pool" weld into a cast iron surface.
Just to post in this link concerning welding, can't get at the back side of the port to weld it up. And from what I hear, you can't "pool" weld into a cast iron surface.
08-19-2003, 07:03 PM
#8
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Ok, I've been cleaning the offending part with acetone and for the life of me, I can't see how this thing is causing a coolant leak. There's no visible hole, light doesn't shine through it, and acetone pooled around the spot in question does not leak through.
So the facts are:
1) car burns coolant but only seems to do so under boost conditions above .75kg/cm2
2) car does not seem to burn coolant under .7kg/cm2 or under vacuum conditions
3) coolant residue was found in the uderside of the oil filler cap
4) if I boost above .75kg/cm2 and the engine "swallows" a bit of coolant, I can rev it, drive around a bit and the coolant will clean out and the car operates normally. 100% normal under vacuum conditions. Vacuum levels are just fine, about 375mm to 410mm at 1100 rpm
4) there seems to be a pitted spot in the front rotor's primary intake runner
5) we can press on it with force and it does not open up or give way
After I cleaned it, I had the idea of sealing off the ports. They did this at the shop too, using hands to block off the ports and using compressed air. A thin sheet of paper, stuck in the coolant passage below the port fluttered when air was applied to the port.
I decided to duplicate that experiment but I used thin latex gloves and towels to seal the ports. The soft latex provided a good seal. I also plugged the small port inside the injector bung and proceeded to blow as hard as I could (no jokes please) into the top of the injector port. Enough force was applied that eventually the glove/towel combo was pushed out. No air seemed to leak into the coolant passage.
Since it only leaks when boost is applied, I would think that the coolant would leak under vacuum conditions as well as under boost. The coolant system is under far greater pressure, 16psi to be exact, so theory holds it would leak all the time, no?
I'm about ready to run back over to Walmart and purchase a bit of playdough to really seal everything off but I'm almost ready to bet my left nut the "pit" in question is not causing the leak. I'm footing the bill for the whole fiasco since the shop has determined that my port job was responsible for the coolant leak. I'm now wondering if it's a convenient scapegoat for not assembling/checking the engine properly.
Where are common areas that leak coolant? Besides problems with porting, afik, they can leak around the spark plug area. We tested that. Nothing. Now, if the plates weren't checked for flatness and there was one small area which was uneven, higher boost levels would expose this weakness wouldn't it? If the bolts weren't tensioned properly, unevenly or too tight, problems could be created, correct?
Thing is, if the engine were expanding laterally, it seems like oil/coolant would leak OUTSIDE the motor as well, not just inside. But there appeared to be a bit of coolant in the oil. Not much however.
Here's the offending pit inside the primary runner. This photo is taken looking down the primary injector port. Notice the "plug", round shaped piece of metal of different grade in the bottom of the port. Both sides have this. The pitted area is on the outside of this plug. You can see the scrapes from trying to press through with a screwdriver (had a right angle head). I'm going to duplicate this post in a new thread.
So the facts are:
1) car burns coolant but only seems to do so under boost conditions above .75kg/cm2
2) car does not seem to burn coolant under .7kg/cm2 or under vacuum conditions
3) coolant residue was found in the uderside of the oil filler cap
4) if I boost above .75kg/cm2 and the engine "swallows" a bit of coolant, I can rev it, drive around a bit and the coolant will clean out and the car operates normally. 100% normal under vacuum conditions. Vacuum levels are just fine, about 375mm to 410mm at 1100 rpm
4) there seems to be a pitted spot in the front rotor's primary intake runner
5) we can press on it with force and it does not open up or give way
After I cleaned it, I had the idea of sealing off the ports. They did this at the shop too, using hands to block off the ports and using compressed air. A thin sheet of paper, stuck in the coolant passage below the port fluttered when air was applied to the port.
I decided to duplicate that experiment but I used thin latex gloves and towels to seal the ports. The soft latex provided a good seal. I also plugged the small port inside the injector bung and proceeded to blow as hard as I could (no jokes please) into the top of the injector port. Enough force was applied that eventually the glove/towel combo was pushed out. No air seemed to leak into the coolant passage.
Since it only leaks when boost is applied, I would think that the coolant would leak under vacuum conditions as well as under boost. The coolant system is under far greater pressure, 16psi to be exact, so theory holds it would leak all the time, no?
I'm about ready to run back over to Walmart and purchase a bit of playdough to really seal everything off but I'm almost ready to bet my left nut the "pit" in question is not causing the leak. I'm footing the bill for the whole fiasco since the shop has determined that my port job was responsible for the coolant leak. I'm now wondering if it's a convenient scapegoat for not assembling/checking the engine properly.
Where are common areas that leak coolant? Besides problems with porting, afik, they can leak around the spark plug area. We tested that. Nothing. Now, if the plates weren't checked for flatness and there was one small area which was uneven, higher boost levels would expose this weakness wouldn't it? If the bolts weren't tensioned properly, unevenly or too tight, problems could be created, correct?
Thing is, if the engine were expanding laterally, it seems like oil/coolant would leak OUTSIDE the motor as well, not just inside. But there appeared to be a bit of coolant in the oil. Not much however.
Here's the offending pit inside the primary runner. This photo is taken looking down the primary injector port. Notice the "plug", round shaped piece of metal of different grade in the bottom of the port. Both sides have this. The pitted area is on the outside of this plug. You can see the scrapes from trying to press through with a screwdriver (had a right angle head). I'm going to duplicate this post in a new thread.
08-20-2003, 05:28 AM
#10
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Join Date: Jan 2003
Location: Perth, Western Australia
Posts: 267
Ports:
I would say that they are not the cause of your leak looking at the photos.
Welding:
I have welded and havent had any problems- the weld seems to pool okay with the cast iron and has filled well (albeit a bit messy until ground back but probably user inexperience).
If it's leaking at higher boost, I would be looking at the coolant seals- check that all housing surfaces are flat within tolerances. Was there any sealant used with the coolant seals? There should be to ensure a good seal, especially if you are using higher boost pressures than stock.
Other than that, the usual cause for leaks are corrosion in the aluminium rotor housings, but leaking through to the oil system is unusual unless a substantial anount gets into the combustion chambers and then past the oil seals...
Check for a crack in the rear iron housing near the top oil dowel- this can be a weak spot and could cause coolant to leak into the oil (and vice-versa).
That's all I can think of!
I would say that they are not the cause of your leak looking at the photos.
Welding:
I have welded and havent had any problems- the weld seems to pool okay with the cast iron and has filled well (albeit a bit messy until ground back but probably user inexperience).
If it's leaking at higher boost, I would be looking at the coolant seals- check that all housing surfaces are flat within tolerances. Was there any sealant used with the coolant seals? There should be to ensure a good seal, especially if you are using higher boost pressures than stock.
Other than that, the usual cause for leaks are corrosion in the aluminium rotor housings, but leaking through to the oil system is unusual unless a substantial anount gets into the combustion chambers and then past the oil seals...
Check for a crack in the rear iron housing near the top oil dowel- this can be a weak spot and could cause coolant to leak into the oil (and vice-versa).
That's all I can think of!