It has been a very long time since I have posted last. Been lots of changes in my life with kids and such. I have been enjoying my truck and using it as often as I can. My truck is leaking like crazy. It seems to have been getting worse. It leaks about 2-3 drips a sec when fully warmed up (will leave a stream on the driveway pulling in). The drips appear to be coming from a hole in the dust cover behind the oil pan. Motor is a 1960 235. Is this a rear main seal issue? I did replace the rear main seal about 9 years ago but maybe getting wear or seal is going bad. I am a motor novice and I have been following many of the threads here keeping this 235 in working order and it runs great but would like to stop this leak. Because it has been so long since I posted, here is a little before and after of my truck. Always something to work on but all the major work is done. Needs some wheels and a e-brake release rod.
WOAH ! . Very nice before and after pictures ! . Yes, the rear main seal is leaking and I suggest the modern replacement rubber seal plus some new main bearing shells, they're probably worn and allowing the crankshaft to move too much . Look at older posts regarding PCV valves , they slow up the leaks more than you'd think .
Thanks for the feedback vwnate! I am learning all I know about this old steel on this thing. I will replace the main seal and shells then and look at a pcv. When I looked under the truck while it was running I could see a decent amount of smoke coming from the breather tube
It's all very basic, the oil vapors you see drifting out of the road draft tube are entirely normal . If you use a single weight CJ (diesel rated) engine oil it will likely leak and smoke a little bit less, me I'd not worry about it . learn how to tune it properly and keep it in sharp tune , you'll enjoy driving it more . I highly suggest any brand of breakerless ignition .
It's been a while since I posted here as well! Mate is right about the pc valve helping. I removed the vent tube from my 235 Chevy engine. Parts store had proper size pc grommet, I think 1 1/8", and I glued it in where vent tube had been. Bought a pic valve with a straight connector, and ran vacuumline up to intake. BTW, Don't run vacuum line against fuel line or you'll get vapor locked from the heat. Replace the breather on valve cover with a plain cap. The cob valve will produce 3 to 4 inches of negative pressure to crankcase. I tested mine with an old valve cover cap that I put a fitting in and tubed to my under dash gauge so I could monitor while driving. My oil leak is at front of engine plate behind timing gears, and this helped reduce leakage to tolerable. Changing my gasket will require pulling camshaft, and "I don't wanna do it."
Bilbo, Interested in your comment about the vacuum line.. On my 235 I think the vacuum line and Fuel line run pretty much the same path to the Carb (From Vacuum advance and Fuel Pump up around the Front part of the engine, between manifold cover and radiator hose the around to carb.). So this puts the lines pretty close to each other.. If there is a space between them, is that sufficient to avoid vapor lock? I assume if they are not actually physically touching that should be fine? -James
Hey James. The vacuum advance line has no "flow" in it, so there is no heat produced by it. The pcv line has hot crankcase vapors flowing through it and gets quite hot on longer runs. Hope this clarifies the issue.
James, The vacuum advance line has no flow in it, so it is not a source of additional heat. The PCV vacuum line is pulling hot crankcase vapors up to the intake manifold. On longer vehicle runs this line gets quite hot, so that's why the needed separation in routing. Hope this helps clarify the issue. I just realized that I've posted the same information twice! Senior moment, I guess. Gonna leave this one for the photos though....
I did find Deves tech writup on PCV and will use his as a guide. He has all the part numbers and such and good pic's. Installing a PCV System in your 216/235/261 Engine
FWIW, I highly suggest placing the PCV valve up as close to the intake manifold as possible ~ it will suck out less oil this way .
I looked at Deves installation and have a couple of suggestions... One is that there is a rubber grommet available off the shelf that will push into the hole where the vent tube is removed, and it is made for a PCV valve. I also replaced my valve cover breather with a solid cap. This helped reduce my oil leak. I did measure the vacuum on the crankcase at all running conditions and it was consistently around 3 to 5 inches. I've been well satisfied with this setup.
