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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: smoothlandin on August 15, 2015, 06:09:32 pm
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83 chevy k20, 350, th400, etc
Original block, smog heads, etc. I just swapped the cam for lunati voodoo, put on edelbrock performer, etc.
In the truck of course, should've pulled it...
I can't get the distributor to drop the last half inch. I know about the oil pump driveshaft, and how they mate, but my problem is that the distributor won't even go in enough to reach the oil pump shaft. I pulled my oil pan, I originally thought the oil pump shaft was the problem, and can see that the oil pump shaft and the distributor are in line with each other, albeit 1/4" away, and the problem must be where the distributor gear and camshaft meet.
I know that the cap will need to turn 20* or so when the teeth mesh together on the cam and dist, but I just can't get them to mesh. My distributor is a factory replacement, with no odd wear, and the cam is brand new. I've searched, called engine builders, talked to mechanics, etc, nobody has ran into this, and some even came over to help, to no avail.
It has been 2 days trying to get this thing together, in the past I've swapped distributors quickly and painlessly.
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Pull the gear off the dist shaft and see if the distributor drops into place.
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Just did what you said b dist drops right in..so maybe I need a different gear?
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What is the camshaft part number?
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Unless its a roller can, your gear should be fine.
You say the dist & oil pump are lined up, but the dist won't drop down all the way.
Most of the time I remover & replace a dist, its to replace an intake manifold, so the motor is not rotated with the dist removed. A cam swap is a little different.
I'm guessing your gears (cam & dist) are off by a hair. If you turn the dist to line them up, you throw off the dist/oil pump alignment.
Ir's tough to explain, but I set the oil pump shaft so its a little offset from where I want the dist to fall into place. Now as I rotate the dist to line up with the cam gear, it kinda falls into place, with the dist gear, cam gear, and oil pump all lining up.
It usually takes me a few tries so I can get it so the dist looks "centered" and the aluminum vac port is not aimed at the firewall or carb once I set the timing.
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Not a roller cam..I think i know what you mean, as you drop the dist down, it turns a few degrees, changing the correlation of the rotor, and possibly missing the oil pump shaft alignment. Maybe I'm just off by that little bit but I've never had one do this to me.
As far as part number, lunati voodoo 10120702.
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Exactly, I'm thinking its just off by a hair.
If you give BD the part # he can check, but the only time I've heard of people having to change dist gears is when they install a roller cam. Then they have to install a hardened dist gear, but I think it has the same # of teeth on it.
You could also try turning the harmonic balancer a degree or two forwards or backward and see if it helps the gears line up.
We gotta solve this so you can break in your new cam on a Saturday night.
The neighbors will love it.
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Ha, lucky for me I live in the country..I can run open headers all I want, just one neighbor and they're ford guys; so you know, they're constantly working on their trucks :P
Anyway, I still have the timing chain and whatnot exposed, I have the engine at tdc on #1 ,of course, but have tried turning the motor a little to help ease the gears together, but still no luck. I'm actually wondering if I can install the gear on the disributor 180* from its current position, I can see a little wear on the gear when it's facing the cam with the rotor facing #1, maybe that is causing some of this greif
Closed up shop(backyard) for the night, good t storm coming, but I will be at it in the morning; as long as my wife is cool with that..
Thanks for the help
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Your welcome.
One last thought for the night.
If your oil pans still off, you can remove your oil pump. Now you can turn the rotor every which way to see if you can get the gears to line up.
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There's nothing unique about that camshaft. It's fully compatible with the factory distributor gear. When you get back to it in the morning, it will probably almost assemble itself. :D
I think Fitz's evaluation is spot on. So, try a different method. With cylinder #1 on TDCC, drop the distributor into place so the rotor rotates into the appropriate orientation. Then have a helper bump-bump-bump-bump the starter over with the key as you gently settle the distributor into position the final 1/2" to 3/8". The distributor should seat before one complete revolution of the engine by just tapping the starter a little bit at a time. Then you can crank the engine around and recheck rotor alignment.
If difficulty persists, remove the oil pump completely and stab the distributor. If there actually is interference between the distributor and cam gears it will be clearly evident with the pump removed.
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Well, just pulled the oil pump after a few more hours of trying the suggested methods, but the distributor still won't go in. The gears just don't mesh together.
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This is a long shot: Look at the gear pitch of the old camshaft. Now, remove the distributor and look down the hole at the new cam gear (or look up from underneath). Do both cam gears have the same pitch angle?
Contact Lunati (http://www.lunatipower.com/) Tech Support, (662) 892-1500 (8 AM - 6 PM CST). Let us know what happens.
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You mentioned that your dist gear had some wear on it.
Do you have a spare dist you can try?
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The new cam and old cam have the same gear pitch, or close to it, I don't think that's the problem anymore.
But, with the sunlight just right, shining up from under the truck, and a bright flashlight, I think I can see the problem. I didn't even think this could happen.
I'm pretty sure that's either a cam bearing or something in between the cam gear and the end bearing surface. I took some pics, but it's tough to see in there.
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Sounds like you will be pulling the motor.
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You know that was my plan upon buying this truck, then life happened and I tried to make due with what I had.
Thanks everyone for the help.
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What is plan B?
Are you going to do cam bearings and give it another shot? Or just look for another motor?
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I'm kinda at a loss as to what to do at the moment. I bought the truck with the intention of swapping in a 454 or caddy 500 to use for towing and side jobs. All while restoring it while using it. Done it before..
Life stuff happened so I just bought a cam and headers, cleaned out the parts bin, and crossed my fingers. My budget went to moving, long story. Now I have no budget and no engine!
I guess I will be looking for another 350 at this point, use what i have for it, because I can't see myself doing only cam bearings on an engine that could really use a rebuild, but stranger things have happened. We'll see. I think I ought to start a build thread, to keep me motivated on this project.
Luckily this isn't my daily driver.
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That's a bummer Smoothlandin!
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In my younger days, I'd be tempted to reach down there with a long screwdriver and try to nudge the bearing into place. What's the worst that can happen?
Now that I'm a little older, I'd still try the same thing.
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Funny you say that about reaching in there...that's the plan for this afternoon!
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Ya, it might not be the best idea, but I figure at this point, what can it hurt.
The caddy motor would be cool. Too bad most of the old donor cars that you would see on the side of the road for $500 are long gone.
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Well, got the rear most cam bearing back in place...put the thing back together, but upon tightening rockers, found the second to furthest cam bearing out of its hole, lifter wouldnt go down all the way.
Bringing the engine to a local builder to install new cam bearings for $45. He is interested to see it, this is the first he's heard doing this. We will be checking the cam as well to make sure it is the right spec for sbc cam bearings.
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Curious - how do the old cam journals look?
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Honestly, the journals don't seem any more worn than they should, but there is a line on the rear journal that looks as though the cam bearing might have rode toward the edge of the journal and out of the block a little, if that makes sense. But no other crazy wear.
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The caddy motor would be cool. Too bad most of the old donor cars that you would see on the side of the road for $500 are long gone.
The 472 is a stump puller too. A friend has one in a 77 GMC K20 that he uses to tow a big Airstream up the grapevine at highway speeds.
He claims it doesn't feel like he's towing anything.
From orbit on my Android.
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Were the bearings slid forward or backwards out of place? Did you find yourself tapping/prying the cam into place for some reason? Maybe it's just me, but it seems odd/unrealistic that this could happen carefully sliding the cam into place being careful not to bump the edge of the cam bearings.
If they moved out of place by carefully removing or installing a cam, it would seem unlikely that they will stay in place while the engine is running for any length of time.
This was a running engine that you just decided to change the cam one day, correct? Keep us posted, Lorne
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I didn't use any force to remove the old cam; it slid right out without hesitation. I almost wondered why it was so easy to pull it out. I installed the new cam the same way, very smoothly. A little resistance towards the back of the block, but I figured it was just due to it being a new cam that wasn't worn. I didn't have to use any force to install it, nor would I have, I'm not one to use a hammer or pry bar when working on an engine.
The truck was running, but quite rough. I tore it down and upon seeing the timing chain severely stretched, decided to replace the timing chain and figured the cam while I was at it.
Upon further inspection, and why the distributor wouldn't go in, the rear most cam bearing was riding on the cam, in between the cam gears and the bearing journal. Once I saw that was the issue, I pushed the bearing back into place, easily, by using a screw driver. The bearing had to be worn pretty good if it just slid back in without any force. I figured I would just put it back together for the whatever it was worth and look for a donor in the meantime. When a lifter mid way through the block wouldn't go down, I reached in and could feel something moving around on that lobe. I crawled underneath and by rotating the engine could just see the second from the back cam bearing riding on the cam. The thing that seems odd is that the bearing in the back was moved forward, like it came out with the old cam, and the second bearing was moved back like it moved in with the new cam.
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VERY strange indeed! Reality is...for the cost to fix the block, it's junk now. Those bearings have had to be turning in the block & wore down to be able to slid them back in place. It would sure seem like they will move again & there has to be metal filings all through the engine...better come up with Plan B quite soon. Take Care, Lorne