viven44 Posted July 31 Share Posted July 31 Ok I want to talk about oil consumption.. I’ve roughly put about 700 miles on the build and wanted to wait until I addressed all the low level oil leaks (valve covers, etc) The 460 on the bronco is using oil and a lot. A quart every 300 miles or so. No leaks anywhere…. No smoking.. Compression is excellent on all cylinders so I don’t think anything malicious in the short block. Possibly valve guides…. Would high mileage oil help any here if so? But my top suspect is my PCV valve. I kept the original and it routes to the Edelbrock. There is very strong suction while idling. I guess I should remember that at idle the PCV should be partially closed, but not sure if that’s the case here… Big Blue 2WD seems to have a valve of some kind ahead of the PCV valve, I’ll see if I can find a pic. That entity is missing on the bronco .. I’m running conventional 10W-40 Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 31 Share Posted July 31 You need to partner up with Rene on the vanishing oil. I don't see how you could be burning a quart every 300 miles and not have a huge blue cloud following you everywhere. Valve guide seals would be smokey when you started the Bronco and when you let off the throttle (intake vacuum sucks oil past the guides) But if it's not on the ground and your plugs look good the only other place it could be going is into the coolant system. Is your antifreeze murky brown? Do you have an oil slick on top if you remove the radiator cap? The PCV is meant to be a controlled vacuum leak that allows engine vacuum to pull combustion byproducts and condensation vapor out of the crankcase before it creates sulphuric acid in the sump. Is the PCV hose full of oil? Not oily, as normal, but like you're using it as a funnel. Again, you'd see this coming out the exhaust and your plugs would foul. Link to comment Share on other sites More sharing options...
viven44 Posted July 31 Author Share Posted July 31 You need to partner up with Rene on the vanishing oil. I don't see how you could be burning a quart every 300 miles and not have a huge blue cloud following you everywhere. Valve guide seals would be smokey when you started the Bronco and when you let off the throttle (intake vacuum sucks oil past the guides) But if it's not on the ground and your plugs look good the only other place it could be going is into the coolant system. Is your antifreeze murky brown? Do you have an oil slick on top if you remove the radiator cap? The PCV is meant to be a controlled vacuum leak that allows engine vacuum to pull combustion byproducts and condensation vapor out of the crankcase before it creates sulphuric acid in the sump. Is the PCV hose full of oil? Not oily, as normal, but like you're using it as a funnel. Again, you'd see this coming out the exhaust and your plugs would foul. Jim, negative on the coolant. Still green as can be. Nothing murky. On the PCV, my hunch is there because -- plugs are not fouled but don't look great either -- there isn't blow-by if I start the truck with PCV valve removed and valve cover opened and let it run/get hot... there might be very mild blow-by which is hard to see... but if I let the PCV valve do its thing inside the valve cover (Suction) and then remove the PCV valve, there is all kinds of smoke/vapor/blow-by coming out of the valve cover The hose is pretty empty when I pull the valve... but there is little left in it because the strong vacuum does a good job of emptying it... but I can definitely see the inside of the valve all oily. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 31 Share Posted July 31 Jim, negative on the coolant. Still green as can be. Nothing murky. On the PCV, my hunch is there because -- plugs are not fouled but don't look great either -- there isn't blow-by if I start the truck with PCV valve removed and valve cover opened and let it run/get hot... there might be very mild blow-by which is hard to see... but if I let the PCV valve do its thing inside the valve cover (Suction) and then remove the PCV valve, there is all kinds of smoke/vapor/blow-by coming out of the valve cover The hose is pretty empty when I pull the valve... but there is little left in it because the strong vacuum does a good job of emptying it... but I can definitely see the inside of the valve all oily. The valve is going to be oily, that's it's job. I'm not sure what you mean by "all kinds of smoke/vapor/blow-by" There's always going to be some. No engine has 100% ring seal. Maybe you should do a leak down, or at least compare all 8 cylinder compression numbers? A quart every tank!?!? Something is very wrong. Link to comment Share on other sites More sharing options...
viven44 Posted July 31 Author Share Posted July 31 Jim, negative on the coolant. Still green as can be. Nothing murky. On the PCV, my hunch is there because -- plugs are not fouled but don't look great either -- there isn't blow-by if I start the truck with PCV valve removed and valve cover opened and let it run/get hot... there might be very mild blow-by which is hard to see... but if I let the PCV valve do its thing inside the valve cover (Suction) and then remove the PCV valve, there is all kinds of smoke/vapor/blow-by coming out of the valve cover The hose is pretty empty when I pull the valve... but there is little left in it because the strong vacuum does a good job of emptying it... but I can definitely see the inside of the valve all oily. PCV on Big Blue 2WD What is that quarter-turn valve looking thing ? The bronco is missing this at the moment.. It is probably in a storage box somewhere when I removed the 460 from the pickup Link to comment Share on other sites More sharing options...
viven44 Posted July 31 Author Share Posted July 31 The valve is going to be oily, that's it's job. I'm not sure what you mean by "all kinds of smoke/vapor/blow-by" There's always going to be some. No engine has 100% ring seal. Maybe you should do a leak down, or at least compare all 8 cylinder compression numbers? A quart every tank!?!? Something is very wrong. It has been a while since I ran compression but the last time I ran it, think the compression numbers were acceptable.. those plugs are the old ones I pulled out when it was still running on the 4180.. they were badly fouled. The new plugs after 700 miles don't look anywhere as bad. Not as good as Gary's that he posted recently but you can tell they are starting to get fouled. I spot checked a couple of cylinders recently to see what the new timing chain did to the numbers and the numbers are still in the same range... Link to comment Share on other sites More sharing options...
85lebaront2 Posted July 31 Share Posted July 31 PCV on Big Blue 2WD What is that quarter-turn valve looking thing ? The bronco is missing this at the moment.. It is probably in a storage box somewhere when I removed the 460 from the pickup That is a hot idle compensator. It opens with high underhood temperatures to lean the idle mixture slightly. They have been on some carbureted engines since the 60s. Carter AFBs had them in the main body between the secondary clusters. Link to comment Share on other sites More sharing options...
viven44 Posted July 31 Author Share Posted July 31 That is a hot idle compensator. It opens with high underhood temperatures to lean the idle mixture slightly. They have been on some carbureted engines since the 60s. Carter AFBs had them in the main body between the secondary clusters. Thanks Bill, it seems that the hot idle compensator shouldn't affect PCV function if I am not mistaken. That is a good bit of knowledge to remember. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 31 Share Posted July 31 Thanks Bill, it seems that the hot idle compensator shouldn't affect PCV function if I am not mistaken. That is a good bit of knowledge to remember. I've seen them in vans, but never in a pickup. Link to comment Share on other sites More sharing options...
viven44 Posted July 31 Author Share Posted July 31 The valve is going to be oily, that's it's job. I'm not sure what you mean by "all kinds of smoke/vapor/blow-by" There's always going to be some. No engine has 100% ring seal. Maybe you should do a leak down, or at least compare all 8 cylinder compression numbers? A quart every tank!?!? Something is very wrong. Yes I agree it is not normal... on Big Blue 2WD where the compression is definitely more questionable (few cylinders close to 100 while others in the 120s), I do not lose any oil whatsoever (up to 2000 miles I have gone where I saw maybe the oil 1/8 - 1/4 inch down on the dipstick). I was losing a quart every 50 miles when I first bought the truck! I am planning to add a witness catch can see if this picks up anything abnormal. Also going to replace the PCV valve while at it. I did install a new PCV valve on Big Blue 2WD early on. https://www.amazon.com/dp/B081N392BN/?coliid=I1NZ8HU7ZC92TL&colid=3IGQF00LDI4AO&psc=1&ref_=cm_sw_r_cp_ud_lstpd_BSN7PFWA4M8NH11YAXT1 Link to comment Share on other sites More sharing options...
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