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TBI Distributor gear for HotCam?

This is a discussion on TBI Distributor gear for HotCam? within the Performance forums, part of the General Discussion category; I've been having serious trouble with my distributor gears since installing the LT4 Hot cam. First, I didn't know it ...

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    TBI Distributor gear for HotCam?


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    I've been having serious trouble with my distributor gears since installing the LT4 Hot cam. First, I didn't know it was an issue until I knew something wasn't quite right with the way the engine felt, then later that week the engine quit when the gear finally gave up. I replaced the distributor with another one for the time being till I could get that special "Melonized" gear from GM.

    First, I went and ordered the 10456413 gear. That number kept showing up where ever I looked. A week later, and $42 lighter I got that gear and went to install it, and it was too big for the shaft on the distributor. Thanks to the kind people of this forum I traded the dealership for part number 19052845 - .428" Shaft. for $31 ($11 cheaper). The gear looked exactly the same as the #413 gear, but it actually fit. Same texture to the outside of the gear too. Now, about a month later, I pop'd the dizzy out for an inspection, and it appears to already be a bit worn down. Not nearly as bad as the previous two gears, but its heading that direction. I was expecting to find a black gear with shined up contact surfaces, but nope, its eating it up.

    I am worried that even with the good distributor gear, that I will be changing them as frequently, if not more often then I change my oil.

    Is the new gear that I have now really melonized? It was quite a bit lower in price, so I was a bit concerned that it wasn't the melonized one, But putting the 413 and 845 gears next to one another, they appear identical, so I thought nothing of it.

    Anyone else share my pain?

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    Re: TBI Distributor gear for HotCam?

    Im runnig the Hot Cam also with a stock replacement distributor.There should be know
    difference in the Hot Cam gear.I ran a flat tappet cam before the Hot Cam with same
    distributor.About 3000 miles and no issues that I know of.Are you running a high volume
    pump and heavy oil?I think you got a problem causing gears to fail.Do they look like they ve
    been properly lubed?
    87 Chevy Shortbed -383 ,serpentine belt set up,vortec heads,Lt4 HotCam,Edel 2912 inatake,Holley TB,Gm 80lbs Injectors,
    stock ignition with MSD coil,700r4 Probuilt Autos shift kit,still tuning with EBL

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    Re: TBI Distributor gear for HotCam?

    Yes, High volume pump, 10W-30 Mobile 1. Im going 5W-30 on my next oil change. The Oil pressure is a bit on the high side with the 10W-30. It's definitely a factor since it adds strain to the gear. I'm fairly certain that the gear gets enough lube, They are always dripping wet when the dizzy comes out.

    Who knows, maybe the 5W-30 will cure it? One thing Im sure of... Another gear is in my future.

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    Re: TBI Distributor gear for HotCam?

    I used the gear for the L98 TPI Camaro/Firebird engine which was factory roller. Roller cams require a different distributor gear or it gets chewed up like yours is doing.

    You got lucky. I had to shove aside all the filth in my head and dig way back in the chronicles to remember who the original thread poster was so I could look it up. It was YenkoST.

    Post 12. http://www.fullsizechevy.com/showthr...stributor+gear

    Your welcome.
    1995 Silverado - ported vortec heads, 4L80E, efans, LT4 Hot Cam, Rear disc brake conversion w/drilled and slotted rotors
    1999 NBS Silverdo - transgo HD2 shift kit, 3 inch dynomax ultra flow, Ford keys and 305/70-16 Mickey ATZs

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    Re: TBI Distributor gear for HotCam?

    You guys are going to make me pull my distributor and check my gear.Is there a physical differnces
    that can be seen with the eye?
    87 Chevy Shortbed -383 ,serpentine belt set up,vortec heads,Lt4 HotCam,Edel 2912 inatake,Holley TB,Gm 80lbs Injectors,
    stock ignition with MSD coil,700r4 Probuilt Autos shift kit,still tuning with EBL

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    Re: TBI Distributor gear for HotCam?

    Not that I know of. I suppose if yours is worn out thats a pretty good indication.
    1995 Silverado - ported vortec heads, 4L80E, efans, LT4 Hot Cam, Rear disc brake conversion w/drilled and slotted rotors
    1999 NBS Silverdo - transgo HD2 shift kit, 3 inch dynomax ultra flow, Ford keys and 305/70-16 Mickey ATZs

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    Re: TBI Distributor gear for HotCam?

    I put a L98 roller 3000 miles ago
    I used the small ID mellonized gear
    I have the PN somewhere
    I'll post it later, it's off to Boy Scouts

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    Re: TBI Distributor gear for HotCam?

    Whn I bought my 97 rcsb L31 truck in 1998, it was used with 17,000kms on it. At around 85,000kms (GM warranty at that time was only 60,00kms or 36,000miles)after replacing poppets, cleaning poppets, plugs, wires etc etc to try and cure the cruise/lightthrottle miss, the distributer was pulled and a knifeedged distributer gear was found. Half of the gears on 1 side were knifedged, and the other half were worn 1/2 way.

    GM had issues with their OEM gears and the melonizing process. If you never want to have to do another dizzy gear, get the Comp Cams polymer dizzy gear. You will need to fashion a sleeve to use it on a Vortec truck, but it works well.

    PAge #2 has pics of a dizzy gear that looks exactly like mine did at 85,000kms. The link also talks about different Vortec distributers and teh polymer gear.

    http://www.pacificp.com/forum/viewto...olymer&start=0

    the GM roller cams are induction hardened and are harder than niormal flat tappet cams to keep the roller lifter and cam lobe from destroying each other. As such "normal" distributer gears will be "digested" by the roller cam distributer gears.

    There is a mod that can be performed that increases the oil flow to teh distributer gears, at least on the Vortec engines. Its a s simple as cutting a groove on the dist body.

    5w-30 10w-30 oil will have the same viscosity when at temperature. The letter with the W after it is the low viscosity number or measured by SAE(society of automotive engineers) at 0 and the high viscosity number (no W) is the high temp number and is measured at 212F by SAE. Going from 10w30 to 5w30 will not change the oil pressue when the engine is warm at all. It just means the oil will flow a bit better at low temps.

    Nice post digging Old Red, that was a good one.

    peace
    PAuly
    Last edited by Pauly; 09-03-2010 at 09:35 AM.
    97 GMC 2wd RCSB 5.7, s10 2700 footstall, Hooker 24621hkr LT's , 2.5" cats dual 4"pipes exit B4 pass. side tire, custom driveshaft 3.42 G80 FIPK MAF descreen GM/Mercruiser Marine intake manifold 29lb LS2(EV6) injectors Ed Wright PCM(best mod), LT4 KM 14.8@94mph 2.007 4000lbs 122mph

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    Re: TBI Distributor gear for HotCam?

    Looks like you got the correct gear,
    A little wear is OK
    I'll pull mine out in a few weeks and post a report
    I'm running the same gear.

    19052845 - Distributor HEI Gear, Small Cap (.425). You must use this gear with the new roller
    cams. This is a hardened gear. Also fits some Mallory distributors. Fits some Mallory distributors. [Old P/N 10469459]

    http://webcache.googleusercontent.co...&ct=clnk&gl=us
    Last edited by Old88; 09-04-2010 at 09:12 AM.

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    Re: TBI Distributor gear for HotCam?

    This thread has got me wondering. I've been fighting a gradual but steadily worsening WOT breakup problem on my 95 since putting the roller cam in. It didn't happen at first but I would say within the first few thousand miles it appeared at around 5000-5500 and now its doing it at as low as 3500 rpms and I keep getting this rocks shooting down the exhaust misfire pop at cruising speed. I attributed this to weak valve springs because I know they aren't quite enough but maybe my GM hardened melemonized gear is wearing out. I had the distributor out a while back replacing the pick up coil and no obvious wear jumped out at me then but its worth checking.
    1995 Silverado - ported vortec heads, 4L80E, efans, LT4 Hot Cam, Rear disc brake conversion w/drilled and slotted rotors
    1999 NBS Silverdo - transgo HD2 shift kit, 3 inch dynomax ultra flow, Ford keys and 305/70-16 Mickey ATZs

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    Re: TBI Distributor gear for HotCam?

    Quote Originally Posted by oldred95 View Post
    This thread has got me wondering. I've been fighting a gradual but steadily worsening WOT breakup problem on my 95 since putting the roller cam in. It didn't happen at first but I would say within the first few thousand miles it appeared at around 5000-5500 and now its doing it at as low as 3500 rpms and I keep getting this rocks shooting down the exhaust misfire pop at cruising speed. I attributed this to weak valve springs because I know they aren't quite enough but maybe my GM hardened melemonized gear is wearing out. I had the distributor out a while back replacing the pick up coil and no obvious wear jumped out at me then but its worth checking.
    I thought you had narrowed it down to valve float.
    87 Chevy Shortbed -383 ,serpentine belt set up,vortec heads,Lt4 HotCam,Edel 2912 inatake,Holley TB,Gm 80lbs Injectors,
    stock ignition with MSD coil,700r4 Probuilt Autos shift kit,still tuning with EBL

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    Re: TBI Distributor gear for HotCam?

    Quote Originally Posted by 383TBI View Post
    I thought you had narrowed it down to valve float.
    I have it narrowed down to something is wrong. I know my springs aren't up to snuff but whether or not that is the true problem I don't know. Checking the gear for wear doesn't cost me anything.
    1995 Silverado - ported vortec heads, 4L80E, efans, LT4 Hot Cam, Rear disc brake conversion w/drilled and slotted rotors
    1999 NBS Silverdo - transgo HD2 shift kit, 3 inch dynomax ultra flow, Ford keys and 305/70-16 Mickey ATZs

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    Re: TBI Distributor gear for HotCam?

    Quote Originally Posted by oldred95 View Post
    I have it narrowed down to something is wrong. I know my springs aren't up to snuff but whether or not that is the true problem I don't know. Checking the gear for wear doesn't cost me anything.
    If the gear was the problem, I suspect you would notice the miss at low throttle angles like when you are cruising with the TCC locked. This ide to the ECM commanding much more timingalong with leaner a/f ratios at low throttle/low load than at WOT. WOT operation usually clears up distributer gear problems, at least early on in the gears deterioration.

    Checking the gear will set your mind at ease though.

    peace
    PAuly
    97 GMC 2wd RCSB 5.7, s10 2700 footstall, Hooker 24621hkr LT's , 2.5" cats dual 4"pipes exit B4 pass. side tire, custom driveshaft 3.42 G80 FIPK MAF descreen GM/Mercruiser Marine intake manifold 29lb LS2(EV6) injectors Ed Wright PCM(best mod), LT4 KM 14.8@94mph 2.007 4000lbs 122mph

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    Re: TBI Distributor gear for HotCam?

    I run a Comp Cams composite plastic poly gear in my camaro. The gear is not cheap but it will not wear down either. I was going through a gear a year when I used the bronze ones. Here is a link to the gear I am running.

    http://www.summitracing.com/parts/CCA-12140/
    Last edited by BOTTLEDZ28; 09-13-2010 at 06:14 PM.

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    Re: TBI Distributor gear for HotCam?

    I was reading one your discussions about the distributor gear wearing out after running a roller cam. I am having the same issue. I was wondering if anyone found a good solution. The only thing i can think to do is have a bushing machined so I can run the .500 composite gear made by comp. I have spent alot of effort to to maintaine the tbi setup on a performance build to get stumped here. thanks

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    Re: TBI Distributor gear for HotCam?

    Here's the gear I used
    http://paceperformance.com/i-5133742...rnal-coil.html
    9000 miles and no problems on a GM roller cam with HV oil pump.

    I did use some Dow Corning GN moly paste on the cam gear and distributer gear when I installed it. Using the right lube upon install will increase service life.

    Here's the lube
    http://www.ellsworth.com/display/pro...?productid=401
    Last edited by Old88; 01-03-2011 at 05:23 PM.

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    Re: TBI Distributor gear for HotCam?

    Dear Old88,
    Thanks for the information. I have been fighting little issues with the motor and the drive gear has been at the heart of it all. The wear was gradual with the first gear so i didnt realize it untill it wiped the teeth off of it. I tried lunati's everwear steel gear that summit recomended and it didnt last a month, my stock gear went for 6 months. 60 dollar lesson learned there.
    oh yea thanks for your patience this is the first forum i have ever joined, and i am a little slow to figure it all out. Ive been trying to add photos to my profile and can't even get that to work

 

 

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