GlenH Posted January 30 Share Posted January 30 I have a 68 Camando with the 225 V-6. This Jeep was bought by my customer a short time ago and has not been able to drive it because it keeps destroying distibutor drive and driven gears. Not getting oil to the timing chain area. Oil pressure is 40 psi cold, oil to rocker arms is good. Pulled the distributor and manually primed the pump and get 40 PSI, but no oil to the chain area. Looking at the factory oiling diagram it shows oil squirting forward through the cam gears and spacer. Pulling the cover off, and the timing gers off, I can see a small hole drilled in the cam toward the front cam bearing, but pressurizing the oiling system with the cover off, i'm getting oil seeping from the cam and crank bearings, but nothing from the oiling hole in the cam. How are the front gears and chain oiled? Should I modify the timing cover by drilling a small spray hole into the main feed port to spray oil everywhere? Any advice is welcome. I'm a 40 year ASE Master Tech, but this one is eluding me. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted January 31 Administrators Share Posted January 31 Hi, GlenH...I understand your dilemma and frustration...There is a reference within the Jeep (i.e. Buick) description of 225 Dauntless V6 oiling: "The timing chain is lubricated by splash of an oil stream from which oil is directed to the distributor drive gear from the fuel pump eccentric on the camshaft." I emphasized the fuel pump eccentric's role. If the eccentric is either not in place, is incorrect for a 225 V6 or is altogether missing, that could be an issue. The eccentric plays a role for both the distributor drive gear and chain lubrication. Check this closely and get back. Did an engine builder or owner remove the eccentric and install an aftermarket electric fuel pump? Is this the wrong eccentric and not for a 225? The eccentric could affect both the chain lubrication and failure of the distributor drive gear and driven gear. Moses Quote Link to comment Share on other sites More sharing options...
GlenH Posted January 31 Author Share Posted January 31 Yes, it does have the eccentric in place and facing the correct direction. I can see the hole in the camshaft and it lines up with the keyway slot in the eccentric and the cam gear. the issue I'm seeing is the cam has to be pressed up hard against the block to get any oil through the hole. It does have the button and spring, but I'm not sure that is enough to push the cam back hard enough to enable the bleed hole to feed oil forward. I've seen some videos on the front cover being modified at the main oil feed with a small hole to direct oil up on to the gears and chain. Have you seen this done, And what is your feeling on this mod? Thanks for your input. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 1 Administrators Share Posted February 1 GlenH...The button pressure is important. Are the camshaft lobes okay? Is there excessive forward thrust of the camshaft that is overcoming the spring pressure? Or is the button spring weak? I've not done the oil feed modification but understand the premise. If the hole size can be determined before drilling, that could be a solution. I have always done the Melling High Volume oil pump modification/kit, which essentially extends the length of the pump rotors/gears and uses a spacer to increase the depth of oil pump gear cavities. That kit would assure plenty of oil volume if you do the modification described. When installing the Melling kit, be certain to align the machined spacer plate precisely before drilling/indexing for the included alignment roll pins (2). (The shims in the kit are for temporary use only while centering the spacer plate with the new gears.) This positioning is critical for the pump gears to run on center and not damage the kit's metal spacer, the new oil pump gears or the timing cover bores. Let us know more about the orifice size for the drilled passage and so forth. This would be a direct bleed but not much different than the rocker arms. With enough pump volume and the correct orifice size, there should be no issue. Moses Quote Link to comment Share on other sites More sharing options...
GlenH Posted February 1 Author Share Posted February 1 Moses, thanks for the response. The rebuild on this motor is not very old, but I don't know the quality of the work. This has been through a few owners since the build and they get frustrated and patch it long enough to sell it. This owner wants it right and so do I. I might do the cover mod as well as replaceing the thrust button and spring. The size they use for the mod is a 1/64th drill bit, and then they deform the hole to make a spray pattern. Looks like it would give plenty of oil to the gears without sacrificing volume or pressure to the rest of the motor. The only thing I could see the cause of the cam to walk forward is lifter pressure on the lobe, but is that valve spring pressure or cam lobe grind? I don't want to replace the cam/lifters and still have the same issue. Maybe a stronger thrust button and the cover mod is my best bet. I have heard of the melling kits causing excessive drag on the oil pump drive which can shear the distributor pin. I'll try the cover mod and new thrust button and let you know what I find. Thanks for the input, Moses. Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 2 Administrators Share Posted February 2 GlenH...A 1/64" hole, if adequate lubrication, would not be an issue. Bleed-off would be minimal if this is a proven method. Worth a try? If the camshaft and lifters appear "normal" with no wear indicated, I would replace the button and spring just as a precaution...Be aware that production Buick V6 engines have one bank of lobes ground with a slight taper in one direction; the opposite bank is ground with a slight taper in the opposite direction. (Lifters have a convex base, so the taper is not an issue.) This centers the camshaft in service. Aftermarket cam grinders often ignore this measure and grind the lobes without a taper. This allows the camshaft to thrust forward with more pressure. Check the lobes for front and rear facing taper. A footnote: In building Buick V6s for racing, an aftermarket needle bearing thrust button assembly was often installed. A plate was installed at the backside of the timing cover to serve as a mating/wear surface for the needle bearing thrust button. The clearance and fit between the thrust button and stop plate had to be carefully determined...This was the allowable camshaft thrust forward. It's easier to use a button and spring if the camshaft lobes were ground correctly with opposing tapers. I've not had issues with the Melling K-20IHV kit. Again, gear and plate alignment is crucial. (The kit comes with two alignment roll pins and assembly spacer shims to center the gears and spacer plate.) Choice of the correct pressure relief spring is also critical. The aim is not to increase oil pressure. This pump kit assures adequate volume. If the pressure is boosted too high by using the wrong spring, the result will be a heavier load on the distributor drive gear pin. Although oil viscosity plays a role here, too, I'm guessing that nearly all owners run a multi-vis. A stiffer straight weight oil with slow pour in cold weather could conceivably put excess load on the distributor drive gear pin. My guess, though, is that sheared pins are likely from too much pressure, enhanced by the longer gears. Summit Racing (see link below) has a photo of the complete kit. Note the shim stock, two roll pins, a variety of springs and the gear tooth lengths: not extreme, just enough to raise volume. When selecting the right oil pressure spring, the factory setting for a stock 225 Buick/Jeep V6 is 33 psi at 2,400 rpm with the engine warmed. That's not a lot. With stock bearing clearances, 40 psi at 2,400 rpm would be plenty. (This is not an AMC inline six or small-block Chevy V8!) These engines need adequate oil volume, not excessive pressure. Anyway, I'm not trying to sell anyone on the idea of this Melling high volume pump kit. However, it's been in the aftermarket for many decades with successful installations, mine included. Check out these links: https://www.ebay.com/itm/253006482096 [The marketer has shared the installation instructions. This is a busy pump kit to set up properly. Center the plate when indexing/drilling for the roll pins. Use the correct pressure relief spring and an accurate oil pressure gauge to set the oil pressure at 2,400 rpm. Testing the pressure and picking the right spring are the extra steps that can make a difference.] Current best price and ready availability at: https://www.summitracing.com/parts/mel-k-20ihv Keep us posted... Moses Quote Link to comment Share on other sites More sharing options...
GlenH Posted February 8 Author Share Posted February 8 Hey, Moses...I didn't remove the camshaft from the engine. I think we were on to something with the cam being ground incorrectly causing forward thrusting of the cam. I performed the front cover modification by drilling a .030 hole in the output passage of the oil pump at an angle from the inside of the hole, upwards toward the distributor/cam gear. With the cover on the bench I hooked up an oil supply reservoir to the pump inlet side of the cover then plugged the outlet side and turned the pump with a drill. Oil shot out at a steady stream and then I peened the hole over slightly to cause a spray pattern. After reinstalling the cover, I started the motor without the fuel pump installed and saw oil spraying everywhere and had 35 psi oil pressure warm. This is the link to the procedure I used. https://youtu.be/5CQx6t4SvMc?feature=shared. It looked as though the cam was staying pushed back against the block because while running and revving the motor, the cam wasn't walking back and forth. The oil coming out of the fuel pump hole was getting slung off the chain so I am confident everything is getting lubed well. The customer was complaining about a whining noise which I don't hear now. I'm calling this fixed, and if anything changes, I'll chime back in. Thanks for the input, Moses. Happy Wrenching! Quote Link to comment Share on other sites More sharing options...
Administrators Moses Ludel Posted February 8 Administrators Share Posted February 8 GlenH...Sounds good and thorough, too. Your method and testing should be helpful to other Dauntless V6 225 owners. Thanks for the link and follow-up! Moses Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.