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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Ok guys, I have a REAL strange problem here... I heard a strange rasping sound from my engine today. Located it from the distributor. Pulled off the cap and noticed massive play in the upper bearing. Pulled the distributor out and yep... upper bearing nearly total out of round. Distributor shaft has visible signs of waer. How is that possible?
Also, the distributor gear shows signs of wear from the camshaft gear.
Just for info, engine has been completely rebuilt 10 months ago, new crank, new cam, new chain, EVERYTHING is new except the distributor itself... I can't understand what has happened here... please don't tell me something is wrong with my engine or the cam gear... anyone ever struggled with that?
Well I would say you aren't getting sufficient oil to the distributor/camshaft gears. The shaft should be pulling oil up that helical groove, but based on the gear wear there isn't much oil there for it to pull from.... It is often recommended that the distributor housing be modified with a groove to allow additional lubrication directly on the gears.....
A quick glance at the grumpy site covers a lot. I may have missed it but a high volume oil pump with high viscosity oil (20W-50) can also cause heavy gear wear.
Other items covered in that linked page, billet cam with wrong cam and distributor gears. To much downward pressure on oil pump shaft (need to shim up distributor housing from intake manifold.
Under the pickup coil in the distributor should be a felt pad that is saturated with oil. This helps lube the upper shaft.
VERY interesting and overwhelming info on grumpy's website... I don't know what to think about that... My engine is bone stock rebuilt. I used the stock cam, bought it from RockAuto, Sealed Power CS808. Where can I find the correct gear that matches this cam? My oil pump is also a normal Melling M55, no HV or HP oil pump. Used that in combination with the IS55E oil pump driving shaft, that eliminates the need of the nylon thingy that often falls apart.
My oil pressure is alway good, I tested that after engine rebuild with a mechanical oil gauge, it matches the gage in the instrument cluster nearly perfect. Pressure is on cold engine about 50-55 psi and on warm engine never under 30 psi. Checked immediately today when I heard that rasping sound... I use Mobil 5W-40 oil in this engine, it is a factory roller block on my 92 TA.
I'm confused now... Certainly I will buy a new distributor now and check the cam gear with an inspection camera for wear. But how can I find out which gear I need? Should I write an Email to Sealed Power? Or does anyone here know which gear to use with this cam?
And what I absolutely don't understand: Why is the upper bearing worn out? How is this possible, there seems to be no oil or not enough oil. How can I find out if the distributor has insufficient oil?
Man, I won't sleep tonight for sure...
Last edited by J.C. Denton; 02-16-2019 at 05:17 PM.
2. Composite (offers great life, conforms well to the mating cam gear, and is compatible with ANY camshaft gear material)
3. Melonized or hardened steel (material that OEMs use with factory roller cams; many aftermarket distributor manufacturers use these as the default gears for their distributors)
4. Bronze (conforms well to the mating camshaft gear and will not damage the camshaft gear, but it is a self sacrificing gear intended to be used in race applications only and should be replaced about once a year)
If you have a cast iron hydraulic or solid flat tappet cam, your distributor gear options are:
1. Cast iron distributor gear
2. Composite distributor gear
If you have an austempered ductile iron hydraulic or solid roller cam, your two options are:
1. Melonized or hardened steel distributor gear
2. Composite distributor gear
If you have a billet steel hydraulic or solid roller cam, your two options are:
1. Bronze distributor gear
2. Composite distributor gear
COMP Cams recommends the composite gear because it is compatible with all camshaft gears – flat tappet, austempered cast iron cores, and billet cores. If the steel gear is not hardened, it is not compatible with either of the roller cam types.
Note: If you have an austempered core hydraulic roller cam and a .500Ë shaft distributor with a steel gear, verify with the manufacturer of the distributor that the steel gear they use is a melonized or hardened steel material and it will work fine.
Tech Tip courtesy of Comp Cams
I'm looking for a picture that shows where to drill 2 holes in the lower distributor housing to lubricate the shaft.
You also need to verify that you are not putting pressure on the oil pump drive when you clamp the distributor down, as RBob said above.
MSD distributors have 1 hole as shown.
*
Last edited by NoEmissions84TA; 02-16-2019 at 11:04 PM.
Well I would say you aren't getting sufficient oil to the distributor/camshaft gears. The shaft should be pulling oil up that helical groove, but based on the gear wear there isn't much oil there for it to pull from.... It is often recommended that the distributor housing be modified with a groove to allow additional lubrication directly on the gears.....
What was wrong with the original cam that you replaced it?
Nothing special... I rebuilt the entire engine and didn't want to use a 26 year old cam with the new lifters and stuff. Doesn't make sense to me.
Because we have similar emission tests like in CA over here in germany, I didn't want to use a street racer or hot cam, I just wanted to have an engine that is bone stock and totally rebuilt. And now, what a mess...
I measured the depth of the distributor today, seems to be perfect. No wonder, it is a stock block with a stock intake, a stock cam and a stock GM distributor.
i also drained the oil today into a clean pan. I seem to have a greyish haze / veil / mist (don't know the correct english word) in the oil. But no visible or big metal flakes. I also have a magnetic drain plug, on the metal tip were very very fine dark / grey flakes. Is it possible that this is from the piston rings and the defective distributor gear? Oil pressure was always fine as I mentioned before.
Engine has about 1500 mls since the rebuild and I changed oil three times since. Look at the pics I took today:
I am really unsure if this is ok or not... I also made a video of the oil, but I need to upload it to YouTube or something and embedd the link here.
New gear and old gear didn't like each other. I don't know much about Sealed Power cams other than I wouldn't have even thought to consider them. Oil and magnet look OK for an engine going through break in. But really that should be all done by a few hundred miles. Yes you will get some ring shedding, and some of that is clearly from that distributor gear.
Looks to me like new gear didn't like old gear and they didn't lap in well. No moly lube on them for break in? I'm not entirely sure about the shaft bushing situation but are you 100% sure that wasn't in-progress from before the rebuild? I would be checking the housing diameters of the old and new distributor to determine how much oil is going to leak by and then possibly, depending on dimensions, cut a groove for additional oiling.
I don't think you are totally hosed, but I would want to base my next move on the cam gear condition. In fact I would be suspect of the gear being cut wrong perhaps.... I would just swap the cam for a genuine GM piece or just put that factory cam back in. On a roller motor there is no need to match new lifters to a new cam. Nor is there really a good reason to replace a non-worn cam.
Here is a picture of old an new cam next to each other. To me it looks like the exact cam like the original. What would you guys swap in that has original cam specs? Over here in germany you can't just walk into some parts store and order cams for Chevy engines... the parts dealer will look at you like he has seen a ghost. Ask for BMW or Mercedes and you can order the smallest screw or a complete engine and it will be available immediately. All we can do over here is order online over the great pond and pay crazy prices on shipping. All info we can get is from you here, RockAuto, Hawks and Summit... I wouldn't even know where to buy an original GM cam... RockAuto doesn't list them. What I want to say with that: Please apologize for my dumb questions, but over here I know not a single person who is really into SBC engines. Yes, they are are around, some people drive them, but I just don't know who to talk to about this problem.
I also uploaded two videos on youtube, one with the oil haze and one I took today from the cam gear. Let's hope it works... I am not really into youtube and pc stuff in general...
I've tried to find a new Genuine GM cam but they are long discontinued. Any tips from you what to buy that's as close as possible to the stock one? If I can't find anything, I may put back the old cam in, but I need to inspect it first. But before, I'll have to find it... I know I didn't tossed it in the trash, but can't find it right now... What about a SLP 51002? Some guy around here is selling a NOS one, but we don't know if it will fit, on the box it says "SLP51002 CS3311/3312 HR112 +4, Serial #H 0137 03658403322".
What I found out, it is close to stock... any recommendations what cam to use instead of the old original one?
It has very similar specs to the original L98 camshafts. Which I believe the later LB9's had basically the same cam as the L98. The Comp cam has a little more lift, but not much more than you might get from 1.6 rockers - which don't require tuning in my experience
Based on that Comp cam's California CARB certification you can virtually guarantee it's going to run very similar to stock and will absolutely not affect emissions equipment, etc.
GD
Last edited by GeneralDisorder; 02-20-2019 at 12:24 PM.
Thanks for the link to the cam! Good choice for me I think.
But before replacing the cam, I want to know if this will happen again. I ordered the cheapest distributor from RockAuto, Cardone part. Received it the other day and swapped the ICM, cap, rotor and pickup coil for the nearly new Delco parts from my old distributor. I measured everything, sits perfect in the engine and matches with the cam gear perfectly. I put plenty engine assembly paste on the gear, turned the engine by hand and removed distributor again, gears line up just fine. Installed it finally, set timing and let it idle for about half an hour. Ran just fine, no misfiring anymore. I also filed a little notch in the distributor base as described before.
I now want to drive about 250 miles or so and then remove the distributor again and have a close look at the cam and distributor gear again. If the new gear looks the same like the old one, I will definitely swap the cam.
My only concern is that it might make more metal. Be sure to warm up the engine fully before adding any revs or load while performing this test so as not to engage the oil filter bypass valve and potentially suck debris into the engine.
After a whole season with a lot of miles put on the car I wanted to bring this thread to an end (hopefully forever). As I said in my former post, I ordered the Cardone dizzy from RA. I modified it as grumpys performance recommended. Cut a slit in the dizzy to let oil spray directly onto the cam and dizzy gear. Before installing the distributor I checked oil pressure with a mechanical gauge and verified that I had a strong oil beam coming out of the bore for the cam oil galley. Checked with a bore scope and everything was perfect. Perfect pressure. So I installed the low budget dizzy, set the timing, changed the oil two times within a week and removed the distributor 3 times in the last months. Never had this problem again. No gear wear, no bearing wear, no metal haze in the engine oil. I don't know if cutting the slit in the dizzy base was the key to success or if it was just a bad and old distributor with a previous damage.
All I hope for now is that this will never happen again. Engine runs strong and produces a lot of fun and headturning here in good old prudish VW-contaminated germany.
02-16-2019, 10:15 AM
I would use a scotch brite pad and mineral spirits. 
I know I didn't tossed it in the trash, but can't find it right now... What about a SLP 51002? Some guy around here is selling a NOS one, but we don't know if it will fit, on the box it says "SLP51002 CS3311/3312 HR112 +4, Serial #H 0137 03658403322".
