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B20 Engine In Cam Swap

CRatcliff

Member
Joined
Nov 21, 2016
Location
Seattle, Washington
Hey All, I'm swapping the cam in my B20 without taking the engine out of the car and have done a ton of searching on the subject and there are a few answers I'm not 100% clear on.

  1. I know I need to use a screwdriver to prime the oil pump - where is the actual place to prime the pump?
  2. Is the distributor drive gear and the oil pump gear the same thing?
  3. The distributor drive gear will only come out about 80% of the way, then it gets all jammed up. It spins freely, though. Do I need to take it out the rest of the way or is it fine at this point?

I think that's all for now. Engine head is off, lifters are out, distributor is off (drive gear is as mentioned above), timing cover is off, I'll be taking the timing gear off today (aluminum timing gear is coming in from VP Autoparts next week), engine is set where 1st cylinder is tdc, and the distributor rotor arm is marked where it was before I took it off, so I should be able to set the engine timing back easily.

I know I need to grab a few parts from the old cam - I plan to take the old one out and wait at least a day before putting the new one in - just specifically listing all of the steps to do before install (assembly paste, spacer on cam, check the thrust plate), and IIRC there is a couple more things to pull from the old cam.

Been reading these two:
https://forums.tbforums.com/showthread.php?t=155117
http://www.autotraining.edu/blog/installing-a-performance-camshaft/

And following the Hayne's manual. Let me know if you see anything I'm missing, or have any answers to the questions above! Thank youuuuuuuuuuu.
 
1. You can use a long thin screwdriver to turn the pump through the hole where the distributor/oil pump drive gear goes.
2. Yes, it's the same thing.
3. As long as the distributor drive gear is up high enough to clear the gear on the cam it should come out. You may need to rotate the cam to get the lobes past the distributor gear shaft though.

All you need from the old cam is the woodruff key and the spacer.

You'll probably find that when the dots on the cam and crank gear line up the engine will be at TDC for #4, not #1.
 
Okay soooo I may have really ****ed up. The bearing puller I was using to remove the timing gear MAY have hooked onto the cam retainer instead of the timing gear, and instead of pulling the timing gear out, may have pushed the cam in. I'm not SURE that this is what happened, but the cam retainer is bent out right about where the hole in the timing gear was. If this happened, my fear is that I may have pushed against the water seal at the back.

1) is this even possible that this happened?
2) is there a way to check?
3) what to do at this point?

Thanks all.
 
Pics of the carnage.

Are there witness marks from the puller jaws on the back of the retainer plate? It may have been bent by a hamfisted mechanic while installing the plug in the back of the block.

It would be firing on 4, but would be TDC on 1 and 4 - that's been my experience. TDC for 1 and 4 are the same.

AFAIK, in all engines with an even number of cylinders 2 will come to TDC at the same time. The reason I pointed out that it will likely be firing #4 is so that he'll know to set the distributor/oil pump drive gear in correctly. If you assume that the engine is @ TDC #1 when the dots are aligned on the timing gears and drop in the drive gear, it'll be 180? out.
 
Yeah, your probably right. I don't think it pushed the cam plug back but you'll find out when you start it up.
 
It'll leak a little oil if it only pushed back a bit. If it came out all the way the plug will be bounced around by the flywheel and it will leak a lot of oil.
 
I accidentally knocked that plug out once, replacing the cam on my old '71 1800E. As the puller popped the cam gear loose (I may have been... tapping on it with a hammer... not advised...), the cam slid backward and I heard a metallic jingling noise inside the bellhousing.

Went ahead and finished up everything on the front side of the engine, then *sigh* pulled the trans. And since I was in there anyway, put on a new RMS and clutch kit, not much point putting it back together with old parts.
 
Also, FWIW, I wouldn't really worry about priming the oil pump on a cam swap. It's really no different than any other cold start. Just make sure you have the cam bearings all slicked up with assembly lube, and use the cam break in grease on the lifters/lobes.
 
Oh man, I'm reallllly hoping that I didn't do that. Thoughts on me pushing the cam gently against the back when reinstalling to see if there's any looseness?

For the cam break in, I was gonna write a huge ol list of questions before starting it, including the whole "run at 3k rpm for 20 minutes" stuff. With a new head and new carbs, I'm not 100% confident in the ability of the car to steadily idle (no clue if the carbs will need tuning!). Thoughts?

--Colin
 
If you've popped the plug out, it'll tell you soon enough as has been covered. Don't be pushing it in further than needed. Just assemble it as if it's all OK.

Just be systematic about the entire thing. It ran before you did the swap, so it will after. Just get it timed so that you understand what's going on and do use lots of assembly lube (I will put moly grease on the cam lobes on a fresh engine - but it's not needed). Run it at 2K RPM for the required time to break it in (basically the parts get used to their new home). Don't re-use lifters.

Even if the cam is 180 degrees out (that's how we all know this problem) - it' won't hurt anything...it just won't start. Get the dizzy drive set properly (if you've screwed it up) an it'll fire right up and won't be a problem. Like, you're not going to wipe the cam or something horrible.
 
It can be a real PITA to get that gear back in. The bottom portion has to mesh with the oil pump slot as it rotates and drops along the angled gear teeth on the cam. You'll probably have to turn the motor over while *GENTLY* pressing the gear down. Press too hard and the oil pump will turn with the shaft even though the tab/slot isn't engaged. And it has to be aligned right* when it's all the way down, and if you turned it to get it to engage that last 1/3rd inch, you won't know if it's on the right tooth until you rotate it around again.

* - it doesn't *really* have to be aligned right - you just need it to fire to the right spark plug wires at the right time, so you can be way off and get it to work by rotating the distributor and/or moving the wires around on the cap appropriately. The main restriction is that the vacuum gizmo on the distributor can limit some potential positions.
 
Oh I won't be using the vacuum on the distributor. BUT, I'm having trouble visualizing the meshing of the gear - anybody have a diagram that includes that? If I understand correctly, the oil pump itself doesn't have any timing - just the distributor gear -> cam -> cam timing gear -> crankshaft timing gear -> crankshaft?

I think as long as the distributor gear matches up to where I marked the distributor before pulling, I should be okay (fingers crossed). I'll just have to try a bunch of times to get it right.

I have the aluminum gear coming in today, and the new thrust plate (sigh) coming in this week from vp-auto. After that, we'll put it all together!
 
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