Hey everyone, i’ve been on G2IC for sometime now, but i havent posted much. This is my first posted so please bare with me.
Ok, so i have JG 301 cams laying around my house so I thought I would install it for some fun. I drive a 92 db1 with the stock b18a1 and wanted to get alittle more top end power.
What i did was:
-set the motor to TDC
-pulled stock cams and installed the 301s
-adjusted the valve clearance to the stock a1 specs
-put everything back together.
After i was done, i double checked my work, made sure it was good to go, i went to start the car and it idled great for about 30 seconds. All of a sudden i hear really loud valve CLAPPING! Not your nomal ticking but super loud clapping. Like metal on metal crime lol.
So i went to remove the valve cover and what i found was two of my rocker arms from the exhaust valve on cylinder 1 and 4 were laying down out of place and one exhaust valve on cylinder 1,2, and 4 were bent.
I just wanted to know if anyone has any kind of input on what might have caused this to happen? Ive been doing tons of research and not much has came up for the 301s. Any kind of help is appreciated. Thanks in advance.
Bad timing, bigger cams make the valve stay open longer and you get a piston punching a valve out for staying in its way to long.
Are the cams named 301 or is that the duration of lift.
If so 301 duration lift is literally a vtec killer cam for full drag engine that push close to 300 hp all motor. Vtec killer cams don’t have the vtec middle lobe on the cams. They look like ls cams.
im gonna go with the valve clearance being off or they were set in the joints wrong. typically they dont hop off like that unless something did it.
did you have any valve 2 valve clearace checks or p2v? stock centerlines on cams or did they need to be degreed in so they would have interference issues?
@da6xsi06 301 is the name of the cams. These are stage 1 LS cams. I didnt even have the car running long enough to adjust the timing.
@projectteg i didnt do any kind of clearance checks. I didnt think it would do this because supposedly these cams run stock valvetrain. So i just dropped it in after alot research here on G2IC and other forum sites. Everybody says just drop it in. And would i need aftermarket cam gears to degree the cams? I dont know to much about the degrees of the cams,
I installed it with stock cam gears.
typically when you install the cam you always want the cam card so you can reference it. sometimes manufactures will change the centers of the cams so stock gear wont work most of the time. im not saying the degree was your issue, but it could have a part to play, typically when rockers fall out something changed demension.
I know you set the crank to TDC, but when you put the camshafts back in did you verify that they went in the correct orientation as well? If you bent valves then your timing was bad, and when I say timing I don’t mean the adjustment on the distributor. I am talking about the cam gear arrows/markings. You said you double checked your work, did you turning the crank a few times with the plugs out to verify that the pistons weren’t hitting the valves?
Yeah i made sure all the cam gear markings were lined up while the crank pulley was on TDC. The only time i turned the crank was after i adjusted the valve lash. Everything sounded fine and i didnt hear anything funny. But i didnt remove the plugs.
Another thing is i noticed that the cam gear markings were off by about 3 or 4 teeth on the cam gears after the valve claps. Before i started the car, the gear markings were lined up. After the claps, the gears were way off. Hope this helps shed alittle more light towards the answer.
only think i could think is the valve lash being off, if you said you set the valve lash at the A1 specs it may be wrong, when i installed my 301 in my ls i used the specs giving for JG and they were a little off from the stock A1 spec
[QUOTE=insanebboy209;2316501]Yeah i made sure all the cam gear markings were lined up while the crank pulley was on TDC. The only time i turned the crank was after i adjusted the valve lash. Everything sounded fine and i didnt hear anything funny. But i didnt remove the plugs.
Another thing is i noticed that the cam gear markings were off by about 3 or 4 teeth on the cam gears after the valve claps. Before i started the car, the gear markings were lined up. After the claps, the gears were way off. Hope this helps shed alittle more light towards the answer.[/QUOTE]
Did it spin freely or was there mild resistance? I have actually turned a crank by hand before and bent the valves. There won’t be any noises, just an awkward resistance for a split second. That’s another reason to always remove the plugs and stop immediately if you feel some resistance.
Also, the FSM says to turn it a few times by hand because sometimes if the belt is not tensioned properly it will move marks afterword. If that happens to you have to start over. That may explain what you are talking about. Maybe it jumped when it started. I can’t say for sure if 4 marks off would cause valve damage but it’s possible.