Lobes & lifters worn- how would you approach repair?

  • I`m procrastinating. Something bad happened to the GTs new engine. I've moved it to rv pad. Rear is on stands, hood is loose...I could've removed and used picker to lift front on way-high stands, but I took a nap instead. This all didn't JUST happen. I've been to machine shop, I've talked to parts supplier, I've examined and measured parts, I've stood there and looked at GT for multiple 10 minute stints...and then took naps. Today I got off work early with intentions of working on Opel- found it right where I left it - but it was cold outside and the house was all mine...so, yeah, I napped. When I woke up there was some daylight left, so I visited opelgt.com, then craigslist, then here. Hmmm, good opportunity for procrastinating with a long post, composed with thumbs on a kindle! Probably won't get read for awhile, maybe not even see a reply (always ensured by not posing a question up front). But hey, this is my impasse - exclusively here at classicopels for anyone to join in on.


    The last 30 miles on my 800 mile old rebuild I began wondering "Has that rocker noise always been so noticeable?" - so I pulled valve cover and ran it, finding #2 hydraulic ex over a turn loose off preload! Must've backed off- easy fix. Noise was much better, but still seemed overall loud... 5 miles later I find it's loose again (but the nut hasn't moved). This sucks.


    #2 ex lifter wouldn't pull out top, so I pulled the head to disassemble. #1 ex lifter was missing its crimped-on assembly retainer and the face was worn concave (as were 2 3 4 ex). #2 ex was worn worst and extracted out from inside. All exhaust lobes had severe corresponding wear-down. #1 ex lifter crimp ring is MIA and probably gobbled low and tossed throughout. Lower of front cam brng is just starting to take shape of cam oil groove. All INTAKE lifters and lobes are 800 miles PERFECT.


    I need to finish a shopping list...so far I've listed head parts, but that could grow depending on how far I need to chase this down. I don't desire starting all over again with block disassembly, but I'm curious if rod and main bearings are polish wearing. Machine shop advises drop, measure and clean everything; Parts Supplier advises just clean and repair head parts, then put neodymium magnets at filter and drain plug to capture remnant debris.


    I'll only hate you ;) for siding with machine shops advice...I know it's safest answer. Maybe there's some shareable experience to help justify needing redo of top only, or perhaps workaround tips to check condition of rest of block in car. Any insights?


    -Dan

  • So... 800 miles after a rebuild, all 4 exhaust lifters are damaged and the exhaust cam lobes are worn. But the intakes are fine. It sounds like the exhausts were set too tight. zero lash plus 3/4 to 1 turn (after they are pumped up) is the setting. If it was just one lifter, I'd say it was defective or the oil galley was blocked and starved the lifter. But all 4?


    One other thought. Was it a new or used cam?

  • I agree, those are good ideas to look in to. Maybe spring bind, too. Lifters and cam were new.


    Incedently, my prior engine rebuild held the surprise of a poorly aligned front cam bearing and thus very restricted head passage oil flow. Failure manifested at front cam bearing, and as chain pulled cam down into wearing bearing, cam oil groove became occupied by the bearing and flow was further restricted. Cam fulcrumed at bearings 2-3 and wore away top half of rear bearing. It made it 2000 miles before losing oil pressure and splattering particulate on to rear of cam sprocket.

  • Hmm, appears I shared confusingly. Sorry. Oil passage blockage and what happened was failure of last engine. I started all over. Exhaust lifters/lobes is current failure of a separate engine build- I reused the timing chain, valves and water pump, but otherwise no parts sharing. This head received hardened seats, new guides & bearings, and threaded galley plugs. Yep, only damage to exhaust lobes and lifters.


    There's no good shortcuts in sight for me... yesterday I drained oil, pulled alternator and distributor, unhooked wiring and fuel lines, modified a pair of tall stands for front of car, and got picker positioned and chained to front suspension for lifting. Engine is coming out soon!