BC Cams installed on 95 KA, now no compression?

[SX APPEAL]

As the title says, I've installed BC Stage 2 cams in my KA, with correct OEM timing (checked, double checked, and triple checked) on a previously running engine. Let me reiterate that part... The engine was running PERFECTLY prior to the install. The cams were installed as per BC's instructions: cut the shank for the FWD distributor off the intake cam, and switch the intake and exhaust. They look completely correct, at #1 TDC compression the intake lobe is at about 9:30 and the exhaust lobe at about 2:30, just like stock cams. Now the engine cranks over all day long but will not fire. Sounds very odd too, like the cams are out of timing. So as I said I checked and checked again and all the timing marks are perfect. Threw a compression tester on it the other day, the engine holds absolutely NO COMPRESSION whatsoever. The gauge will climb to about 30-40 but falls back to zero with every revolution of the engine. This seemed odd to me so I thought maybe the compression gauge was defective. Threw it on the daily beater which obviously runs and drives and it reads just fine. I'm completely stumped here. It's got to be something stupid and easy to fix. It's not like the engine could have blown a head gasket or bent every single valve while sitting there not running for two weeks... Has anyone else had an issue like this with BC Cams? I really don't want to be that guys who has to haul his half done project down to the shop to pay someone to make it run, but I've got limited diagnostic equipment at home and there aren't many things left that I can do.

Just for reference, here's a pic of the cams as they were installed, and nothing was changed with the timing between this pic and the first startup attempt.

[corn322]

What's the clearance between the cams and the valve shims?

[SX APPEAL]

Valve shims as it the "buckets" that sit on top of the valves? I didn't have a feeler gauge when I installed them so I didn't check. Had too much faith in BC I guess. You're thinking the base circle of the camshaft is holding the valves slightly open when they should be closed? Makes sense. I'll try to get a hold of a feeler gauge and check them.

[SX APPEAL]

Well just took a little slip of paper and checked the clearance between the cams' base circle and the buckets, its slips all the way through with just a touch of resistance, the valves are definitely closing all the way. Now what :/

[corn322]

I'm stumped. The only problem I had with my BC cams was the intake cam kept eating valve shims until I replaced them all to get a tighter clearance.

[SX APPEAL]

I have absolutely no clue, it acts and sounds like the cams are 180* out of time with the crank, but I've literally taken a screwdriver and set it down on the piston itself though the spark plug hole and confirmed that the piston is at TDC when the cams are at 9 and 3. What to do...

[darens13]

thats so weird. i know you can slip the paper between the bucket and the cam, so if it was holding the valve open you couldnt do that. i wonder if maybe the buckets are getting wedged inside the head and the springs are not fully pushing the buckets back up. if i were you, i would pull the cams and inspect the buckets. i cant thing of anything else that could cause that. also you might just confirm with a micrometer or a pretty good caliper that the base circle of the bc cam is the same as the stock cam.

[compactfean]

isnt a piece of paper like .002 of an inch? The recommended clearance is more than double that. Id get some fealer gauges in there. Maybe its holding the valves open too long. You should be reshimming the head when you have new parts any ways.

[corn322]

...confirmed that the piston is at TDC when the cams are at 9 and 3. .

But where was the distributor pointing?

[SX APPEAL]

Just a little below 9 o clock, right where it's supposed to.

[TheRealNap0le0n]

did you hand crank the engine to check timing.... did it have any tight spots?

[SX APPEAL]

Yeah, feels pretty normal to crank over by hand

[darens13]

any news on this?

[corn322]

Did you put the stock cams back in and watch it run perfectly?

[SX APPEAL]

Nope, haven't messed with it in a day or two, and in my infinite wisdom I sold the stock cams before I even tried to start it...

[TheRealNap0le0n]

stupid question but u sure the cams arent swapped exh and int... not sure if it would even matter

[SX APPEAL]

Actually I'm confident that they ARE swapped intake for exhaust. This is necessary with BC cams, see first post...

[compactfean]

Have you contacted brian crower yet? Maybe they know something we are missing.

[nissan2.4]

If u have access to a cylinder leakdown tester I would do that and make sure ur losing compression through valves and not just bad timing.

[youngun21a]

That is Weird I also have the bc Cams mine is for a 93,,looks to me that u are off a tooth or ur distributer is out of line..I have added the pics of mysetup and those on the pics are the bc cams,the only problem I had when I installed them was not turning over,And I know I install them correct so I played with the distributer re did the TDC. then bam on the first try it started..

[SX APPEAL]

I don't have access to a leak down tester, this is why I'm contemplating taking it to a shop cause I'm simply out of diagnostic equipment at home. I REALLY don't want to be that guy though. Youngun, gotta say your cams look exactly the same as mine, to me.

[compactfean]

It wouldnt hurt to try one tooth either direction and do a compression test. Just rotate by hand first. If your getting the same low numbers across the board than its off a tooth somewhere. Oh, and the dizzy has nothing to do with a compression test, just keep the tb open and crank it...that's it.

[SX APPEAL]

Yeah you're right, couldn't hurt. I know the distributor is in the right spot, and of course that it has nothing to do with the engine holding compression. Been working on these engines long enough to eyeball it, one tooth in either direction on the dizzy looks COMPLETELY different. I'll mess with it some more after I get my daily, which is also now broken down, back up and running

[compactfean]

Also, can someone confirm you have to switch exhaust and intake cams for a rwd? That makes no sense to me.

[SX APPEAL]

Well thats what BC's instructions specifically say to do, and if you look at the pics of BC cams installed as such vs stock cams, all the lobes are in the same places.

[nissan2.4]

Yeah u do have to switch them, dont understand why but I have them on my ka and runs great. Fired right up on first try

[compactfean]

K thanks....sorry, im an sr guy. Its been a will since I've done any work on a ka. But on a side note.... Everyone keeps referring to where the cams are supposed to be, is your crank at the tdc mark on the crank pulley?

[SX APPEAL]

Yep, everything's dead on

[compactfean]

Damn...the only thing it could be then is cam clearance is barely to tight or its off a tooth. If it was off a tooth though I don't think it eould even get 30-40 psi. I dont know though. I just wanna stick my fealer gauge through the picture and check it! Lol. Whats the cam/bucket clearance on ka's? Ive got solid lifters and needs .006 to .007 in. if I was lets say .002 I gauranty I wouldn't get compression. Maybe your head wa already reshimmed with worn in cams?

[1KleenS13]

Are you sure the crank was in the right spot before you installed the cams? TDC on #1?