Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
Last Saturday I was out for a long drive with my convertible. On my way home, the carb started getting starved for fuel. I made it within walking distance of home before the engine died completely and I coasted to the side of the road.
It turns out that the fuel pump pushrod has been ground down about 3/8". It may have even been slowly grinding down ever since I built the engine. Last summer I got stranded the same way. I installed a new fuel pump and filter and that cured the problem till now. Maybe that was just a bandaid solution for the pump stroke slowly getting shorter.
Tonight I pulled the dizzy and looked inside the engine at the fuel pump eccentric on the cam and I think it looks OK. Obviously the metal from the pushrod went into the crankcase oil though. I'm going to cut open the oil filter and see what it caught. I also have a big magnet stuck to the oil filter as added protection.
A local Mopar friend thinks he has a spare used pushrod that I can have. I'll cover it liberally with moly assembly lube before installing. Should I install it the same way it was before, with the end that was riding on the cam before riding on the cam again?
Should I change the oil, or will changing the filter be sufficient? Any metal particles still in the crankcase should have settled to the bottom of the pan by now, so I'd have to start the car to get the oil stirred-up to try to flush them out with an oil change.
Personally, this kinda reads to me exactly the same as pushrods and cams/lifters being eaten by engines as of late - what oil are you running?? If its the 'current' gas engine oil, I would say that may be your culprit. Dump the oil and filter, and run either ZDDP additive, or do what I do and simply run diesel oil.
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
I am running a standard stock replacement fuel pump. I believe it is an Airtex #267. I installed it brand new last year after getting stuck on the roadside with the same problem (no fuel to the carb).
I usually run Rotella-T 15W40, but this year I have been running Motomaster (Canadian Tire brand) straight-30 Heavy Duty (diesel) oil. This is still rated to an older API standard (CF, I think). It should have more ZDDP than the current CJ diesel rating. Myself and other family members have run this oil in numerous flat-tappet and diesel engines over the years with no problems. <span class='smallblacktext'>[ Edited Fri Aug 10 2012, 08:41AM ]</span>
Joined: Thu May 05 2011, 01:57PM
Location: Chelsea, Mi. USA
Posts: 122
3/8th is ah bunch. Mic the used one before you install it. Anything over 3/16th is a time bomb. I've heard there were some push rods that were too soft floating around out there the last few years. What I'd do is contact Mancini Racing in Roseville, Mi. for a new one. $8 US the last time I bought one. Don't know what the local Chrysler Dealer would want for Mopar Performance but it's the same part Mancini sells !thumb G.L. with it. I resqued a friend on top of the Ambassador bridge with that problem a few years back. Try swapping out that push rod in the staging area before the customs on your side !nervous
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
Cut open the oil filter last night. Only found a single ribbon of steel caught in the filter paper, which may be from the pushrod. There was steel "dust" stuck to the magnet that I stick on the end of the filter. The oil that poured out of the filter into my drain pan seemed grey-coloured compared to the black oil in the pan already. Possibly the oil additives are keeping some finer steel particles suspended. I'll change the oil just to be safe.
I'll go back to Rotella-T 15w40 and add 1/4 bottle of Lucas ZDDP additive. From what I've read, that puts the ZDDP up to a good level for this oil.
The (used) replacement pushrod I found measures 3.216" and as far as I can tell the spec length is 3.220, so it should be OK. While I had my calipers out I measured more precisely the length of my worm out pushrod. It is almost exactly 5/16" short.
EDIT: I am also installing a fuel pressure gauge inline just before the carb so I can hopefully determine if the same thing happens to the next pushrod and catch it earlier, without having to remove the pump and pushrod to inspect it. <span class='smallblacktext'>[ Edited Sat Aug 11 2012, 10:11AM ]</span>
Rottela has plenty of zinc in it still. I sent them a e-mail back and got a lot of great info from them. they are still well over 1200ppm. I run that in the fury now. I just had a cam go bad on me earlier this year. probably from the painter guy starting and stopping the engine a lot for just moving the car a few feet. I found out he would start it, put it in gear and move it a few feet, then shut it off. Not good. Seems strange to hear about a fuel pump push rod going bad though. I would have thought the part on the cam would have went first.
Joined: Thu Jan 20 2011, 11:09PM
Location: San Francisco, CA
Posts: 459
I don't have a solution, but just wanted to share that I have had this issue back when ZDDP wasn't an issue. I had a '69 Dodge 383 Magnum that I had installed in my first '68 Fury and the pushrod wore down to the point that it wouldn't work. What a nightmare to diagnose as I had never heard of this happening before.... I replaced the pushrod with a good used one and the engine ran another 40,000 miles without repeating this problem. Then years later, I had a similar situation with the next engine that I installed, which was a '68 HP 383 from a Polara... On this one, the cam lobe went flat and I ended up installing an electric fuel pump. It happens and it could be worse!!
Joined: Mon Feb 18 2008, 11:08PM
Location: Tewantin, Queensland, Australia
Posts: 405
Same thing happened to my car 2 weeks ago! Lost fuel preassure and i thought the pump had died, stuck on the side of the highway for 2 hours,then on a tilt tray for 2 hours because the stupid driver got lost! Had it fixed in no time thanks to Kiwidan and his mate Dave! I now have a spare in the car, J.I.C!