JohnQ Posted April 16, 2007 Share Posted April 16, 2007 Is this a bad idea to fix my "blowby" problem? It seems to be working. :roll: Link to comment Share on other sites More sharing options...
87manche Posted April 16, 2007 Share Posted April 16, 2007 did you put a PCV valve in there john? I was toying with that myself, as it would right the flow of the cv system, but I was worried that if I truly had cylinder blowby that it might cause too much crankcase pressure, and start popping seals and such. What did that PCV valve come out of? Link to comment Share on other sites More sharing options...
HOrnbrod Posted April 16, 2007 Share Posted April 16, 2007 I did this CCV mod from MadXJ site (http://www.madxj.com/); '93 XJ to '00 XJ CCV Upgrade from the "Engine" section. It completely eliminated blowby on my old 91 HO engine. Not sure if it will work on the Renix engines, but it might. Link to comment Share on other sites More sharing options...
JohnQ Posted April 17, 2007 Share Posted April 17, 2007 did you put a PCV valve in there john?I was toying with that myself, as it would right the flow of the cv system, but I was worried that if I truly had cylinder blowby that it might cause too much crankcase pressure, and start popping seals and such. What did that PCV valve come out of? I picked up the PCV valve from Oreilly's auto. I only have about 10 miles on her since I put it on, but so far no leaks and she's still running. :D Would I be better off putting in a collection bottle like Pete's truck? Link to comment Share on other sites More sharing options...
mjcanoe Posted April 17, 2007 Share Posted April 17, 2007 Hopefully attaboybob got his problems resolved, but since this topic is still alive, here's some info. Back in 1991 oem TSB # 145191 which applied to 4.0L. mentioned replacing ccv w/ #4638360. The original problem w/ the "Renix" jjeep was that the metered orifice was the actual grommet that fit in the V/C, got soft, then plugged. Later 4.0 L. ccv changed that to a grommet in V/C & orifice(2.2mm) in the tube @ V/C end(white fitting) which is still available. There were a number of earlier 4.0 that due to above issue &/or lack of o/f changes did end up w/ "vent stacks" inside of V/C plug up solid w/sludge. These "stacks" are triangular & removable from V/C. When I was deling w/ a badly sludged motor, I would trim about 3/8" from bottom of "stack", kept it away from sludge. Not only does frt. vent allow air flow during running, but allows venting after key off. Hope this helps. mjcanoe Link to comment Share on other sites More sharing options...
mjcanoe Posted April 17, 2007 Share Posted April 17, 2007 Sorry I forgot to mention that on later 4.0 that the brass fitting in I/M would also get resticted/plugged w/sludge. Use proper size drill bit & cleaner. mjcanoe Link to comment Share on other sites More sharing options...
Pete M Posted April 17, 2007 Share Posted April 17, 2007 All I know is that if the gasses can't all go out the designated tube, they will find a new place to escape (usually the front "fresh air" tube). I've got so much blowby that the engine doesn't produce enough vacuum to suck it all out. :( Link to comment Share on other sites More sharing options...
mjcanoe Posted April 17, 2007 Share Posted April 17, 2007 Pete M, That's so true, considering the vent @ frt. is probably 3/8 to 7/16 th ID as opposed to 2.2mm @ccv. If you have high mileage, would be good to do comp./leakdown test. Snap-On also offered a blow-by dection tool, maybe someone in your local has one. It was simple & efficent to use. mjcanoe Link to comment Share on other sites More sharing options...
Pete M Posted April 17, 2007 Share Posted April 17, 2007 Detection tool? :hmm: Interesting. Although I don't need one of those for my 88. :D You can see the puffs coming out of the hose. :mad: Link to comment Share on other sites More sharing options...
mjcanoe Posted April 17, 2007 Share Posted April 17, 2007 Pete M, Hey, I'm sorry, I've been a mechanic for 35 + years. I guess I like tools & get carried away @ times. They have always treated me well in return. But, like you said, some things are obvious, like a paisley print shirt. Take care, mjcanoe Link to comment Share on other sites More sharing options...
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