My friend had some obx cams laying around for his b18c1, figured he would try putting them in. I thought it was a bad idea, having heard many horror stories about them, but I decided to help him anyway.

The first time fitting them in, we bolted them down and gave them a turn to check the retention. They were pretty damn tight, too tight imo. We take it apart, and after micing them up, I find that the journals are slightly larger than the stock cams (about .0005 inch larger).

We figured, no big deal, we'll just polish them down to get a nice fit. After getting them clearanced to my liking, we bolt everything together and set the timing. The motor turned nicely, then we attempt to start it.... After about 1 rotation, it started to make a tapping sound, lots of unhappy thoughts running through my head at this point. It turns out that sound we heard was the timing belt skipping over the intake cam gear, wtf....

I took the belt off and gave the intake cam a turn (with the pistons halfway down so I don't hit valves). The cam was completely seized. We strip everything down, assuming we will be replacing belt valves. To our surprise there were none, I have no idea how, with the cam having skipped 10 or so teeth and all.

We noticed some scratches on the cam journals, so we polished them out. Made sure to put a lot of lube on everything before assembling. This time we spent quite a bit of time turning the cam by hand, trying see if it would seize again, it spun freely the whole time. We did the timing, and go to start it again, same deal with skipping teeth again.

After that we stripped it down and rebuilt it a few more times, trying different things like different belt tension and such. No matter what we do, it still seizes while trying to start. Not sure what else to try, short of sticking the stock cams back in. We've taken it apart so many times that the threads on the cam journals are wearing out, I had to drill 1 out and thread it to a larger size, because it was completely stripped.

I can't seem to figure out why the cam spins perfect by hand, but seizes whiles starting. Anyone else see something like this before?

 

You keep trying to fix an amputated leg with band aids. Stop that. Throw those garbage cams out already.

 

haha! Awesome quote!

 

Sounds like a really bad job. Either your timing was way off that you made piston to valve contact. You are leaving out some details. Are you TDC? Are you lined up with your distributor? When you go and turn by hand, are you just turning the cams or the whole engine? seems like your belt might not be tight enough...

 

the timing was perfect every time, i turn the engine several times after doing timing to confirm it...i turned the cams alone first to see if they were turning well, then i put the belt on, time it, and turn the whole engine by hand a few times

the distributor only has 2 possible positions, and i marked the tdc position before removing it...even it was was wrong, i don't see how that could cause the cam to seize, it would just throw my timing off 180 degrees

i messed around with different belt tensions, both really tight and just using the tensioner spring pressure...a loose belt is not going to seize the cam

doood is most likely right, there's something really wrong with these cams

 

try this, put the oem cams back in, turn the engine over and see if you have the same problems. bet you wont.

 

that's my next step, but once i put them in, they're staying in... if i take the caps on and off any more, the threads might just shear right off

 

well you should have done that first then dont you think? now you'll be up **** creek without a paddle.

 

The distributor can go on backwards and it would cause the problems you describe. I'd double check that.

 

if the rotor were flipped 180 degrees it would just throw the timing off wouldn't it, how could it cause the cam to get stuck? am i missing something here?

 

The groove for the cam is offset so you aren't supposed to be able to put it on backwards. However in practice it IS possible, although you kind of have to force it. What it will do is jam when you crank it.

 

Needs cam, I can help

 

LOL. Hopefully you'll be providing me with camshafts some day