valve knock
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Joined: Mar 2010
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valve knock
68 flh has very bad knock, not a tick, worse at front intake rocker shaft. have listened to all spots on engine, lifter blocks, in. and exh. ports, gearcase,etc. put sifton hydrolics in original blocks, sifton solids, then velva touch lifter conversion. All new parts off my shelf. removed heads and checked guides and seats.ok..front intake knocks at startup and all through rpm and heat range. cold, knock...hot, knock. burnout, knock...gramp drive it, knock. removed all rockershafts and endplay adjusted to .oo6 . new andrews AB cam (knocked with stock cam)gearcase and cover rebuilt with new bushings and bearings. all new parts in valve train but stock valves, guides and seats. lapped valves and checked guides and seats. no leakdown and all seemed tight an ok.
any thoughts????
any thoughts????
Cruiser
Joined: Jul 2010
Posts: 234
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From: Sawdust City
Take a piece of heater hose or garden hose about 2' -3' long to listen with. That always works best to narrow in on a noise. When the heads were off, what did the cyl's look like? Any scuff marks on the thrust sides? Piston could be too sloppy in its bore or wrist pin too loose.
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Joined: Jun 2010
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got my bike back from the shop and jest one of the many things they f'ed up was installing valves that had too long of stems so the valve spring retainers were hitting the sides of the rocker boxes
may want to pull the rocker boxes and look for clearance issues
may want to pull the rocker boxes and look for clearance issues
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Joined: Mar 2009
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From: Niles Canyon Ca.
Sure it's valve train knocking ? The front rod is the " small " one and 74" s will run a long time knocking before anything really bad happens to make you take notice , just something to toss in here . If you pull her down again pop the jug and check your rod play , roll it to the top of the stroke and try pulling the rod straight up and down and twisting the rod like tightening a bolt you should have zero up and down or no noticeable twist movement , side to side shake is common check the service book for specs . Sounds like you've covered the bases pretty well from the cases up so .........................
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little history on the 68 so's all can think on it square. gave it to my son when he came home from afganistan(marine recon sniper) with 58 confirmed kills. after he wrecked it 3 times and tore the hell out o it, i traded him my 05 night train to save the 68 from destruction..lol.. rebuild : 4 1/2 ss stroker rods and wheels, 30 over cast ss pistons, new jugs bored, inspected and cleaned all valves, guides, seats, installed high lift andrews springs and keepers,, micrometered all shafts and bearings and tightened all to factory specs..now to the crappers...the bore was cut egg shaped on the rear cylinder and the fool i can be trusted the shop and never checked clearances. on first ride out..rear cylinder scored, blowing oil out at exhaust flange. teardown i found the egg. new pistons..WRONG..ss quit making the pistons...after months of calling i finally got the old dude ready for retirement..he found me 2 30 over forged pistons and sent them from factory at no cost because of the butts before him wouldn't help. sweet..the last 2 pistons in the world..****..besides the egg shape, the shop didn't clearance the bore to ss specs..to tight..now im out o cash..cleaned up rear cylinder with a trim on my lathe and fixed the bore clearance. togeather again with the knock ...the rear scored and never seized..so i think my rods are ok ...guess i gotta teardown again..from now on i do my own machine work.
Tanx for all the replies..it really helps
Tanx for all the replies..it really helps
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Cruiser
Joined: Sep 2009
Posts: 154
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From: san diego ca
Knocking but can't come in..
As usaul, all great suggestions. Your rocker boxes may be shot out.Or run down and buy a stetescope [sp], then you wil realy nail the noise down. Just my two cents..
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Joined: Mar 2009
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From: Niles Canyon Ca.
Well Tex with all that going on your in kinda in that twilight zone area that comes with making big things outa normal ones . With big engines there's SO many more clearances to check that a stock R&R would have , sounds like you've got more than a clue about engines so go to square one and do the steps man you know the drill . Something is too loose or hitting to make a hard knock like that.
Good Luck
Good Luck
Cruiser
Joined: Feb 2010
Posts: 213
Likes: 5
From: Saginaw Bay Area, MI.
My guess is valve train...broken spring? As stated above,major mods mean major clearence issues. Rocker boxes need clearencing with higher than stock cams. This sucks that you have to go through all this...AGAIN. Stay the course. You'll find it soon enough