Knocking noise/throttle cable question.

#1
Hello! I have a couple of question I would like to ask you guys today regarding a 212 I have been building for quite some time:

Knocking noise:
1. So recently I replaced the head of my predator 212cc non-hemi and once I was done with it, I went to go pull it over without the spark plug in to see if the valves were moving correctly and nothing was loose. To my surprise, I was met with a almost more bassy sounding tick if that makes any sense. It not really like a clunking noise which I assume is what a rod knock it, but I don't think it is because I haven't made any bottom end mods in almost a year and the closest thing to it would be the push rods I put in. For context Ill leave a parts list of what I have so you guys can have a better understanding of what I have and maybe make it easier to see what this "ticking" is.

Throttle cable:
2. For my second question, it's in regards to my throttle cable. I currently have a mikuni throttle cable that I bought off of GPS a while back along side a vm22, but as time progressed I moved up and with the head I bought, I bought a 26mm PWK flat slide that I really want to start using. But when I went to go install the throttle cable into the carb, the metal strand was too short. So, I decided "I'll just cut the housing" and to my surprise the cable is covered in a metal coil which I've found to be very annoying to cut. So if there are any tips you can give me on how to go about cutting down the housing and metal coil, I really appreciate that because it is absolute last thing I have to do besides tuning. Also you're probably wondering why I just don't get a new cable. Well the way the cable is setup, I kinda can't because it's welded to my frame and I honestly thought I was going to be done with the mods, but that obviously never happened.

Parts list:
Hot-265 cam (GPS)
NR racing head (Made to fit Predator with 28.5 and 26mm valves no head shaving)
Stock piston
1.3 ratio rockers
stock length chromoly pushrods (5.200)
stock length billet rod
arc flywheel (6695)
45lbs valve springs
.10 head gasket
26mm flatslide PWK

NOTE: If anyone needs pictures of anything I will happily provide them. Also if anyone wants a video of what the ticking sounds like, ill also provide that.

Again thanks for any help :)
 
#2
Did you already those 1.3 ratio rockers in the motor before you changed the head ? Pulling the engine over with hand rope would not turn it fast enough for a bad rod bearing to make noise. The reason I asked about the rockers, because I can only think of two things, valves hitting the piston or with so much lift your getting coil bind on the springs.
 
#4
OK the 1.3 to 1 rockers are new. Like I said one of those two things are happening. With a 265 cam you are getting .345" of valve lift. Many springs won't go that far in a stock configuration. Usually it requires you to machine the spring pockets deeper, or use a valve that has a longer stem than stock so that the springs aren't compressed too tightly together. Pull off the value cover, turn the engine over by hand until maximum valve lift. Then take a feeler gage and measure the free space between the spring coils. Anything less than .060" is coil bind, meaning that you are collapsing the spring beyond its working limit. FWIW one of my built predator engines running a
265 cam and longer than stock valves from EC Carburetor can only use
1.2 to 1 rockers for the very same reason as explained above. At about
.332" lift it was at the limit . As is it's at .318" . If your springs aren't binding
then pull off the head and check for valve to piston clearance. There's lots of videos that can show you how to do that.
 
#5
OK the 1.3 to 1 rockers are new. Like I said one of those two things are happening. With a 265 cam you are getting .345" of valve lift. Many springs won't go that far in a stock configuration. Usually it requires you to machine the spring pockets deeper, or use a valve that has a longer stem than stock so that the springs aren't compressed too tightly together. Pull off the value cover, turn the engine over by hand until maximum valve lift. Then take a feeler gage and measure the free space between the spring coils. Anything less than .060" is coil bind, meaning that you are collapsing the spring beyond its working limit. FWIW one of my built predator engines running a
265 cam and longer than stock valves from EC Carburetor can only use
1.2 to 1 rockers for the very same reason as explained above. At about
.332" lift it was at the limit . As is it's at .318" . If your springs aren't binding
then pull off the head and check for valve to piston clearance. There's lots of videos that can show you how to do that.
Sorry for the late response. So I narrowed it down and it seems that my valves are hitting the piston. I checked the coils and I can see that they are fine. Another thing I noticed is that if I rock the flywheel back and forth I can recreate the sound over again. It’s weird to me that this is happening considering people use the same engine as me except they use bigger cars and shaved heads. Any suggestions on what I should do?
 
#6
People are using bigger cams but you don't know what mods they may have made to allow them to use it. If the valves are hitting the piston there are only two ways to cure that. Notch the top of the piston where the valves are hitting (labor intensive but free ) or lower the amount that the valves are opening ( changing rockers, wasted money ) . If I were you BEFORE I did anything I would do what is called a squish test where you pull the head and put some playdough on the piston bolt the head back on turn it over by hand a couple of times, pull it apart and measure the thickness of the stuff.You will need a micrometer or a set of calipers that can measure in
.001" . Did you measure the spring coils or just look at them and guess at the space between coils. What brand of rockers did you buy. The ones I have are Gage roller rockers and were $190. Something else you could try is either putting the stock rockers back on the engine or something I like to use on higher RPM builds is a set of CHAMPION shaft mounted rockers.
They are cheap ( $27 ) 1 to 1 ratio so you only get the lift of the cam and hold up very well at high RPM. I know you read stuff on line about people building engines and using this and that but sometimes they don't include all the modifications needed to make it work. The lift you are trying to get with your combination is from my experience ( I have built 4 predators and one clone ) not just a bolt em up and go kind of job. Take the time and measurement to be sure and then proceeded.
 
#7
Just thought of one more possibility. Are you still using the stock valve cover? If so that could be causing the problem. Any aftermarket rockers will hit the baffle inside the valve cover. It can be cut out, or use a aftermarket cover that is taller, and does not have a baffle. Just trying to pick my brain to help you come up with a solution.
 
#8
Just thought of one more possibility. Are you still using the stock valve cover? If so that could be causing the problem. Any aftermarket rockers will hit the baffle inside the valve cover. It can be cut out, or use a aftermarket cover that is taller, and does not have a baffle. Just trying to pick my brain to help you come up with a solution.
No I’m using an aftermarket one
 
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