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Discussion Starter #1 (Edited)
Hey all, looking for some assistance. I just dropped in a new Pertonix Flamethrower distributor (an exact replacement from the one before) into my 408 sbc. I ran the engine for a few minutes a couple different times to do some timing and other adjustments and drove the car a total of five miles. I pulled the distributor out and the gear mesh appears to be off. If you look at the photo you can see it looks like the gear is only engaging the cam gear at the bottom half of the distributor gear. It's almost like the distributor itself is not long enough (although that can't be as I have good oil pressure). How can I correct this so the gear mesh is centered the way it's suppose to be.

Here's the photo. Sorry, it's not a very good one but you can see the wear marks on the bottom half of the gear. No wear marks on the upper half anywhere.
 

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There are 2 different lengths of the dist gear for SB Chev. You need the (.491). Grab the rotor and pull up, if you have slop then get some thin thin washers to shim the gear.
Mark, does the shaft id on sbc dist gears come in different dist gear lengths? You said .491" , I know of only another .500 but was not aware of the lengths. I am aware of the dist shims.
Tell me if I am wrong.
 

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Discussion Starter #5
There are 2 different lengths of the dist gear for SB Chev. You need the (.491). Grab the rotor and pull up, if you have slop then get some thin thin washers to shim the gear.
No slop. Just received this new distributor as Pertronix replaced it free of charge due to the other one wallowing out in the housing. I've been chasing a timing issue and found the gear on the old one had lateral movement. What would cause the bushing in the dizzy housing to wallow out like that....Possible cam walk???

Is the cam in this motor a billet cam, not cast?
Is the distributor seating on a gasket on the intake?
What kind intake manifold do you have?
It's a Comp solid roller, CS 300A-R10. Most likely cast as the engine was built by T&L engines (who is long gone now) so I can't confirm that until Monday when I call Comp themselves. The dizzy was on the gasket and the intake is an RPM Air gap.
 

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No slop. Just received this new distributor as Pertronix replaced it free of charge due to the other one wallowing out in the housing. I've been chasing a timing issue and found the gear on the old one had lateral movement. What would cause the bushing in the dizzy housing to wallow out like that....Possible cam walk???



It's a Comp solid roller, CS 300A-R10. Most likely cast as the engine was built by T&L engines (who is long gone now) so I can't confirm that until Monday when I call Comp themselves. The dizzy was on the gasket and the intake is an RPM Air gap.
Not sure which petronix have, but most are .500 shaft size, if your dist shafte size is .491, then COPO is correct. But I am just wondering if your dist has a .491 shaft and the gear id is .500, then this is a problem. Need to check the dist shaft id.

As for the cam gear compatability with the gear, If your cam is cast (no bronze or clean mill marks between the lobes, I would say you have the correct dist gear material.
You run cast and iron together at least, but billet, requires either bronze ( short life or composite ) and composite I have never run . Most billet cams today have the press on iron dist gear, that allows you to run a stock type or Everwear gear.

Sorry, You mentioned slop? if this is in the dist to gear area, there are shims that can be added to take this out.
 

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If you went roller like I did you need the proper heat treated metal so the cam gear doesn't wear it. My cam is a Lunati and the Lunati gear part no I was told to use is Lunati 89027. Sorry the .491 is the dia of the shaft and not the length. Your wobble wear in the bushing is likely from a cheap soft bush or the bush was not snug enough to begin with.

Heat Treated Cast Distributor Gears are made with a unique material that is specially nitrided to case harden the gear, providing excellent wear characteristics. This increased hardness eliminates compatibility concerns and can be used with steel roller camshafts.

http://www.race-mart.com/Lunati-LTI-89027.html

http://www.lunatipower.com/Product.aspx?id=1430
 

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Discussion Starter #8
Not sure which petronix have, but most are .500 shaft size, if your dist shafte size is .491, then COPO is correct. But I am just wondering if your dist has a .491 shaft and the gear id is .500, then this is a problem. Need to check the dist shaft id.

As for the cam gear compatability with the gear, If your cam is cast (no bronze or clean mill marks between the lobes, I would say you have the correct dist gear material.
You run cast and iron together at least, but billet, requires either bronze ( short life or composite ) and composite I have never run . Most billet cams today have the press on iron dist gear, that allows you to run a stock type or Everwear gear.
The Dizzy is a Pertonix Flamethrower D100810, mechanical advance. I just measured the shaft and it is .500. The ID of the gear is also .500. I looked at the old dizzy (which I still have) and the wear pattern is virtually identical to the new gear. That dizzy has less than 5k miles on it (as does the entire engine as well). So my question is did T&L measure correctly when installing this dizzy or did they use the wrong one???? Would this be causing my timing issues where my timing is jumping around at higher rpms?
 

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The Dizzy is a Pertonix Flamethrower D100810, mechanical advance. I just measured the shaft and it is .500. The ID of the gear is also .500. I looked at the old dizzy (which I still have) and the wear pattern is virtually identical to the new gear. That dizzy has less than 5k miles on it (as does the entire engine as well). So my question is did T&L measure correctly when installing this dizzy or did they use the wrong one???? Would this be causing my timing issues where my timing is jumping around at higher rpms?
Your dist is correct for your application. If you are experiencing timing bounce, it could be do to the dist gear end play which can be easily adjusted. I would even go so far to check to see if this dist is not bottoming out and binding against the oil pump, of which can be solved by shimming the dist upwards, an extra gasket could help.
Since your previous dist gear wear pattern appears the same, I would rule out the gear issue, unless you can see excessive wear on the gear.
Spark scatter can be caused by timing chain lack also, but you said the motor is fresh.
Did you run a cam button in the cam gear up front? If too much clearance in the timing gear to cover, your cam will walk forward, thus making an irregular wear pattern at the cam gear to cam drive gear.
How do you know timing is jumping around at high rpm? Are you jazzing the throttle in the garage? Actual road evidence? Are we talking about valve float?
Lets see what Mark mentions.
 

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Discussion Starter #10
Thanks Don. Yeah, the old gear had the same markings but showed very little wear. In fact, it looks damn new. The timing issue all started after I heard a noise in the front of the engine about a month ago. After troubleshooting and disconnecting the belts I discovered I had some wobble in the water pump shaft. Replaced that, but guess what, the noise was back. The noise sounded like a hammer hitting a tin can.

On top of that, I also noticed my engine was idling high. I checked the timing and it was over 30* at idle. After troubleshooting, I pulled the dizzy and discovered I had lateral movement in the dizzy gear. I pulled the gear and shaft and saw the bronze bushing was wallowed out inside the dizzy housing. Pertronix (who's customer service is top notch) sent me a full replacement dizzy. Once I dropped it into place properly I can set the initial timing no problem. It holds timing and starts to advance at 2300-2500 rpms and then it goes to crap. Timing jumps from 30* -5* back and forth, back and forth. When I took it on the road for the five mile drive it was fine until you hit that magic 2500 rpm then it starts to act up just like a timing issue.

I have not taken the timing cover off so I don't know if they installed a cam button on there. I have a gear drive setup instead of a timing chain. The only device used for cam walk was the stud mounted on the water pump....which I did not install on the new pump because it did not have the boss on there. I can just tack weld a boss on when I take the pump off again. But the timing cover is the cheap chrome kind.

Getting back to dizzy gear, how can I correct the gear mesh on the dizzy-cam gear? How do I check the dizzy to oil pump shaft for proper seating?

Sorry for the long post. Just getting frustrated as I've been dealing with this for a while. And to boot, all of my rocker arms are trashed because T&L used chinese crap so now I have to replace those as well.
 

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Last first, pull the dizzy, check to see how much play you have, should not have over .010 in fact I like 5-7. Normally there is a hardened washer near the dist body, its a wear washer, . If you need to , shim that up. Bad deal on bronze gear. Shimming the dist gear, does move the gear further down into the cam gear mesh, judging by your wear pattern. I like to check this when I build a motor, on the stand.

Now, Set the dist into the hole, does not have to be timed, but set without a gasket, check to see if its off the intake mount flats. Determine how much clearance that is, you can put two gaskets to get it up off the oil pump,.

What happens when you don't have clearance or enuff, when you tighten down on dizzy, it loads the oil pump drive gear into the bottom plate and scores it, this is bad and shaved metal gets into the oil system , hopefully the filter. Also causes irratic timing as pump is being labored by cutting into bottom plate.

Since your are using gear drive, you need to have a button of some type as those gear tend to work outwards, I hate those tin covers, guys used to weld a inner wear pad inside the cover to reinforce but you have no button and a tin cover.
Even the cheapo cam button would do but you need a wear point inside that cover. Any of these will work,
http://www.jegs.com/vpt/COMP+Cams/Camshaft+Thrust+Button
Roller button would be better . I run a Cloyes rigid cover and a button. http://www.jegs.com/vpt/Cloyes/Timing+Cover

Roller rockers, romance items, for a long while I only used ball/seat roller tip. Worked well but I graduated to comp steel roller rocker. http://www.jegs.com/i/COMP-Cams/249/1601-16/10002/-1?parentProductId=1199908

There are other rockers out there but I stay away from the chineese stuff. I was at the sema show last year, they have an auto modeling tool that takes precise measurments of anything you need, then they construct auto parts with cheap metals.

Keep in touch.
 

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Discussion Starter #12
Hey Don, thanks for all of the help. I'll do some work out in the garage and report back my findings. Those rockers you posted the link for are the exact ones I was looking at.

The funny thing about all of this is I have an LSX454 sitting in my garage that I will be dropping in after SEMA, actually closer to the holidays. I'm going to sell this engine but I want to get it fixed properly so I can sell it with a clear conscious and not sell a lemon. I've been on the other end and I am not going to do that to somebody else. I believe in fixing things right the first time and be done with it.
 

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Hey Don, thanks for all of the help. I'll do some work out in the garage and report back my findings. Those rockers you posted the link for are the exact ones I was looking at.

The funny thing about all of this is I have an LSX454 sitting in my garage that I will be dropping in after SEMA, actually closer to the holidays. I'm going to sell this engine but I want to get it fixed properly so I can sell it with a clear conscious and not sell a lemon. I've been on the other end and I am not going to do that to somebody else. I believe in fixing things right the first time and be done with it.
I will be at sema , floating around for 3 days and hitting the bandits by nite.
Good deal on the LSX, I know they fly.
 

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Discussion Starter #14
Ok, just checked endplay in dizzy...012. Once I put it in the car without gasket got about the same amount of movement.

And being that the rockers are all off I was able to put a screwdriver down into the cam gear and I was moving the cam to where it is smacking the timing cover...so way beyond the .010 clearance that it was set to. Looks like I'm pulling the timing cover off to fix the cam walk. This will be a learning experience so any tips on doing this the proper way will help tremendously.
 

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Ok, just checked endplay in dizzy...012. Once I put it in the car without gasket got about the same amount of movement.

And being that the rockers are all off I was able to put a screwdriver down into the cam gear and I was moving the cam to where it is smacking the timing cover...so way beyond the .010 clearance that it was set to. Looks like I'm pulling the timing cover off to fix the cam walk. This will be a learning experience so any tips on doing this the proper way will help tremendously.
Think you misunderstood, Checking the endplay and checking to see if the dist sets down on the oil pump shaft, .
The end play can be cut some maybe to 7 or so.

Then put the dist into position, look to see if the dist is sitting on the oil pump shaft, you can tell by looking to see if the dist round flats, ( where the gasket was) is . If the dist is all way into the hole, then you are good, if there is a gap, more than the thickness of the gasket, you need to add another gasket.
Make sense? There are dist collars to correct this but it can be done with two gaskets.
I had an excessive milled block and I had this problem. I used a gasket on both sides of a large id valve shim (hemi), that corrected my problem of the dist sitting on the oil pump shaft.
Let me know if you still don't understand. read:http://www.circletrack.com/techarti...installation_practices/gear_oiling_tools.html
 

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Discussion Starter #16
Yeah, I did misunderstand but I know what you are looking for. Yes, when the dizzy is in the hole sitting on the oil pump shaft it is flush on the manifold without any gasket. Thanks for clarification on that.

Almost have the whole thing tore apart. I'm down to the crank pulley, balancer and timing cover.
 

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Your timing is bouncing and you know why, the cam is walking and the depth of the dist shaft needs to be perfect. If there's a module under that cap then if the heat is causing it to fail then that'll screw up the rpms too. The Pertronix modules, when they start to fail, the symptoms are like a carb that needs an adjustment. I would also order the correct dist gear for a roller cam unless it has it already or the roller cam will eat it up.

Also if that vacuum advance can is giving you too much advance at idle, you'll need to make a limiter and limit it to 10*.
I had to make a limiter for my B28 VA to stop at 7* but it's 10* full VA, close enough. 10*= 3/32" of movement on the B28 VA can.
 

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Yeah, I did misunderstand but I know what you are looking for. Yes, when the dizzy is in the hole sitting on the oil pump shaft it is flush on the manifold without any gasket. Thanks for clarification on that.

Almost have the whole thing tore apart. I'm down to the crank pulley, balancer and timing cover.
Ok, we got the dist housing clearance set, I would keep going what you are doing on the front cover.

Mark has good advice, keep it in mind. These things you have to sort out , one by one .
At this point I would try to reduce the dist gear to housing a little, .013 is equal to 1° so if you got it down to .007-8, you should be ok now that we know your dist shaft is not sitting on top of the oil pump shaft. .
 

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Discussion Starter #19
Thanks Mark and Don. The dizzy is brand new and is a mechanical advance. I'll just get some shims for it and get that corrected.

Now moving onto the cam walk correction. Once I either replace or fix the cam button (not sure whats on there b/c of gear drive) how can I check end play clearance without removing intake? I do have a magnetic base dial indicator so I can easily put that on the front of the engine. But do you check end play with timing cover on or off? Obviously I have never done this before. Thanks again for all your help. Don, I'll buy you a beer at SEMA this year. I'll be there again.
 

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With the intake on and timing cover on, you can pull the cam then jam something behind the gear so it doesn't move back when you slip the cover on. Use some kids play puddy on the button and see how much gets pressed. If you want the cover tighter where the button is then hit it in the button location with a rubber hammer when it's off the car.
Here's a pic off the net. I would put the dial indicator on the cam gear and use your 2 hands to pull and push the cam for the slop difference.
Off topic that 10* on the B28 can was without using the factory black plastic bushing on the VA rod. I think I'll add the plastic factory bush and see if
I get my 7* I wanted since my initial is 16* with no VA can. I want 23* with the can on at idle.



Add some grease to the end of the cam button.

 
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