valve spring retainer broke on dyno, what was missed
#31
stock behive springs are good for .560 lift. Basically when you put your bike on a dyno, you are testing to see if it can withstand the stresses associated with a max power senerio.....question is...how often do you encounter a max power senerio and are you willing to have a blown engine on your lap if your engine fails. Too risky for me....it's a cash cow for the bike service industry.
Shed some light here speakerfritz, how did you tune your setup? Thats a high dollar setup. I agree, I hate having bike on dyno but unless I choose to do an auto tune unit I dont have a whole lot of choice. Ive tried the PC auto tune and wasnt happy. I really dont understand why bikes are tune so much in the high revs? Why not tune the bike in the rpms we really run (no higher than 4.5 - 5K!) and be done?? Luckily my bike was just about done with the tune so once I get everything back together I should be good to go. Unfortunately like you say I now have a blown motor in my lap. I have had every bike tune on dyno and all have been ok. Anything associated with Harley = cash cow IMHO
#32
#34
stock behive springs are good for .560 lift. Basically when you put your bike on a dyno, you are testing to see if it can withstand the stresses associated with a max power senerio.....question is...how often do you encounter a max power senerio and are you willing to have a blown engine on your lap if your engine fails. Too risky for me....it's a cash cow for the bike service industry.
#35
How does one prepare for this during a build? Should I replace the seats and guides in the heads I get? I am going to run Manley springs and collars, also changing out lifters as one of them looks pretty bad. After much research it is one of two things, either the valve floated a bit or the seat shifted. I am now focusing on trying to find heads and replacement parts needed to rebuild. If anyone has some heads sitting around let me know. The heads I was looking at werent for touring models and needed machining for the motor mount.
If you continue to run a cam like the SnS 583, the OEM beehive springs are adequate as are the OEM valve seats and guides. If budget allows, send the heads to the head porter of your choice for a basic street port; some street port work includes replacing guides with better material but most include larger intake valve, new seals, setting compression for the cam and a SERDI valve job. Cost will range from $400-$500 but will worth it.
Bore your cylinders to .010" OS and fit a set of OEM cast flat top pistons. Put her back together and retune. Should be able to get it all done for about $2000-$2500; less if you can do the work yourself. You will need to get any metal that wound up in the crankcase out and may need to replace oil pump and/or cam plate.
Don't over compensate and spend a bunch of money. There are a gazillion dyno suffessful dyno tunes that did not result in a grenaded engine; the dyno tune was not the problem. Like I said, chalk it up to bad luck and move on.
#36
Old thread but exact same thing just happened to me. New 106 build, Andrews 57H cams, only difference is my heads were ported. New valves, guides, seals. Re-used beehive springs and retainers. Front intake valve smacked the piston and bent, valve guide cracked. Damage wasn't as bad but the valve spring retainer split in two just like yours when tuning the front cylinder on the dyno. We don't know what happened either.
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