Well the new engine that was rebuilt was running fine until the other day. I found out why it quit running/wouldn't start. The distributor gear is ate up and thus not spinning to send spark to the plugs.

I had installed a ZZ4 cam and roller everything. I had picked up a melonized distributor gear from the Chevy dealer and installed it on the Distributor (large cap HEI). I also used the cam retainer plate but not a cam button. When I checked the endplay it was within spec so I thought everything was good to go.

I am unsure what could have caused this? I had posted earlier when trying to figure out why the car wouldn't start and after finding out and posting the reason, I had asked these same questions. I had a couple of replies but I thought it would be best to post this as a new topic since it essentially is.

Could I just have received a bad dizzy gear? Is the more likely that the camshaft is walking too much? What about all the metal from the gear in my oil? I run a 2qt oil filter so I'm hoping that it would have caught the filings.

One last thing, the wear pattern on the dizzy gear was from top to bottom on the gear. The edges were very sharp and of course, the one side was eaten completely out.

Any thoughts, ideas or suggestions?

Thanks everyone,

Pat

 

bump....anyone have any input??

Thanks,

Pat

 

Maybe the oil pump is starting to lock up??? You could take a screw driver or oil pump priming tool and spin the pump with the dizzy out and see how it feels. Just my two cents.

 

Sorry, meant to reply back to you regarding that. It's a Melling High-Volume Oil pump, and it spun freely. I mean there was tension as it started to pump oil, but it wasn't tight like it could barely move. It felt like the proper amount of resistance to pump the oil.

Any other thoughts?

Thanks,

Pat

 

I would put a new gear on it, change the oil, and just drive it. Like you said, you may have just had a bad gear. Runout on the dizzy shaft is good right? I think that if you had a little too much end play on the cam it would just bounce the timing around a little. I couldn't see that chewing up the gear. And the wear on the gear was in the center right? Not on just the top or bottom?

 

The wear on the gear is the whole length of the gear from the top to the bottom of each spline. So, I know it was seated well. Its just something I haven't had happen to me before, so this is a new one for me. :-)

Thanks,

Pat

 

are you running a billet cam?

 

No, a ZZ4 cam from a ZZ4 Crate Engine. But I did use the melonized dizzy gear and I picked it up from the Chevy Dealer.

Thanks,

Pat

 

bump...anyone have ideas as to what could have caused the gear to get eaten up?

Thanks,

Pat

 

mine did the same thing was told a billet cam will eat a stock gear. so i installed a bronze gear and shimed the distributor all is fine so far its been over a year now hope this helps

 

Why are you using a high-volume oil pump on a stock engine? That high volume of oil is trying to pump thru the engine, and it has no where to go. That put extra pressure on the pump, and the distributor gear, which eats it up.

 

It had one on there before and it was less stock than it is now. Here's my build:

350 bored 60 over
flat top hypereutectic pistons
zz4 cam
Melling High volume oil pump
Wix 51794 2 qt oil filter
Aluminum Vette Heads 113 castings
stock roller lifters
comp cams 1.5 ratio roller rockers
TPIS big mouth intake
large tube runners
Hooker 2055 headers jet sterling coated
and a few other extras

But, I wouldn't have thought that another high volume oil pump would have caused these problems. From all that I've read here, it seems like a normal "upgrade if you will" to do.

Thoughts??

Thanks,

Pat

 

bump....Anyone? Please, I just pulled the dizzy again and it looks like its already wearing, with less than 10 miles on it.


Thanks,

Pat

 

I have a high volume oil pump and a ZZ4 cam and have been experiencing this same problem...

Not sure what type of gear to use?

 

I am still experiencing the same problem, however, several people have stated that the high volume oil pump is the cause. I'm confused as the zz4 crate engine comes with a high volume oil pump too, so I don't know what to think there.

A local mechanic told me that he had the same problems with the Chevy melonized gears and he ordered one from Accel and the problem went away. I have ordered the gear and will repost letting you know what I find. In the mean time, I have gone back to the original gear that was on the dizzy until the one from Accel gets here. If it continues to eat gears. then I may try what the poster suggested by going to a brass gear and shimming the dizzy. I am leary about the brass gear since it is a soft metal and I would expect it to get eaten up quickly. So, lots of uncertainty's here.

Thanks,

Pat

 

Yeah, I would be curious to see how you make out.

I actually had bought the right part from GM and put on my stock dist. but that got chewed up becuase the pin got loose for some reason?

Anyway, I had replaced the dist. and kept the gear that came with the distributor on there and that got chewed up too...

Now I have my original stock gear on there which people have said is the correct gear.

I was wondering if the slight up and down play that is in the distributor could be allowing the gear to move enough to get chewed up? Maybe I should get another nylon shim like is on there and try to get that play out.

I did look up the price on the accel gear for iron cams. its like 65 bucks...

definitely post what you find.

If anyone would be so kind as to post the gmpp part# for the dist. gear, I would be interested to see if that would work too?

I cant see how the High flow oil pump is causing it, just doesnt make sense to me.

 

See my post #11. Forcing something thru a place that doesnt have room for it causes extra pressure. That pressure has to go somewhere, and the weakest link is the distributor gear.

 

I will definitely let you know what I find. Kevin91Z, I appreciate all the information and suggestions. You are not the only one who has suggested the oil pump being the issue. As a matter of fact, several have. It is just really strange that before I did the rebuild, there was a Melling High Volume oil pump on there already. Also the ZZ4 crate motors come with a high volume oil pump. So its just confusing that it would cause so much havoc given those circumstances, however, what you are saying makes perfect sense. There has to be something going on that is causing this, like maybe shimming or something along those lines. I hope that my comments aren't upsetting to you as that is not how they are intended, I am the kind of person who has to know 100% the cause, if that makes any sense! :-) So, again, for me it is confusing about the oil pump since there was one on there before and of course the crate engine coming with them too.

Thanks a bunch,

Pat

 

I used a truck pump with 3/4 inch pick up screen and a comp cam. I checked my timing one day and my spark timing was all over the place. Pulled the dist. The dist gear was chewed up. Cam Help said the stock dist gear would work with the cam. I was a dist out of a roller motor. I looked now on Comp Cams web site. They say to use a #12200 dist gear which is $120 on Jegs or Summit. It's plastic. Crane says you can use the stock gear because they have an iron dist gear on the roller cam. I don't know who to believe. The oil pump was not a high volume or pressure. It only had 40-60 psi looked the same size as the stock pump. I used it because the 5/8 screen fell off my last engine. I took the motor apart and the mains were down to copper. I hope the crank will polish up, being I have a l99 crank with alot balance weight. I don't want to pay to balance it again. The cam gear and bearings looks fine. You might want to pull the oil pan off and check a main for metal.

 

Well, after a little more research, it appears that the distributor installed height could also cause this problem. I'm not sure how to check if I'm installed too high, low, or just right. The distributor mounts in just fine, bolts down well and all seems fine.

I am using a TPIS big mouth intake along with a large-cap hei dizzy. Can anyone shed some light on this dizzy installed height scenario?

Thanks,

Pat

 

Use some marking compound on the distributor gear, like you would for setting up rear-end gears, and turn the engine over by hand a couple of times.

 

Thanks for the reply. I hate to be ignorant here, but I'm not sure what I would be looking for. I'm assuming that I would be checking where the marks would be on the gear.

if it's high or low, what should I do then? Get some shims or remove some shims? I'm sure these are probably newbie questions, but I've never done this process before.

Oh and does this sound like a feasible cause to the gear getting eaten up?

Thanks,

Pat

 

Oh, and is that marking compound available at most auto part stores? Any particular brand that you would recommend?

Thanks,

Pat

 

Anyone?

Thanks,

Pat

 

I have no idea if this would make any difference or if it is even relevant. However, I've been heard (never bothered to confirm) that late model tbi caprices and trucks that use big cap distributor have a shorter distributor and thus a different intake manifold than the f-body tbi cars. Which if that has any relevance, you might need to shim your distributor.

 

Thanks for the reply and info!

I am using the TPIS Big mouth intake, so does anyone know if there is a height difference? Also, I am using the 113 aluminum vette heads, so maybe there is some truth to the length being different in regard to the deck height.

If I am taller than I should be, do I add shims to make the shaft top to bottom play less? What if I am too low? I hate to ask these questions but I've never had to deal with this.

Thanks,

Pat

 

Look at these shims

http://performanceparts.com/part.php?partID=184130


look at these adjustable shaft slip collar

http://www.compperformancegroupstore...tegory_Code=GM

Google helps


jms

 

Well its been a while since I last posted here, but I wanted to let everyone know my findings.

I replaced the distributor gear with one from Accel about the time of my last post. I pulled the distributor last night to check the gear and guess what? There is no wear on the gear!!

So it appears that the gears I was getting from the Chevy dealer had something wrong with them. Each time they were supposed to be the melonized gear, but who knows. The two I put on there got chewed up really quickly. This Accel gear shows no wear whatsoever!

Anyway, that appears to have been the problem. For anyone interested, here is the Accel part# that I purchased: #32100

Thanks,

Pat Rogers

 

can you get a pic of one of the old chewed up gears?

 

Sure will. I'll post here shortly with it.

 

Here are some pics of the chewed up gear.

 

And here is a pic of old, original dizzy gear with tons of miles on it.

 

i dont know but that doesnt look like a "bad" gear looks like it failed due to high loads or improper enguagement as the wear starts to form at the top of the gear...

 

The wear is evenly spread from the top to the bottom. All I know is that every gear from Chevy that was put it, got chewed up. Using the old, original gear worked just fine. Using the one from Accel, worked fine. The dizzy was totally seated and engaged. I'm not trying to argue, but I checked and rechecked everything before starting and checking for proper engagement. Unless I am missing something, I believe whole-heartedly that I got it right.

Thanks,

Pat

 

What GM pn were you getting for the gear? I am having the same problem.

 

http://store.summitracing.com/partde...0&autoview=sku

you have an $11.97 cent problem my man click the link above. i cant belive this has stumped so many folks hahaha.

Don't let your cam walk away from you.
When your cam "walks" in the block, it grinds the cam gear against the machined surface. These Summit block protector kits prevents cam walking, and can even free up a little horsepower by reducing friction. These kits include a premium Torrington bearing assembly. Some kits are available with thrust plate, and mounting bolts.

im runnin tripple walve spring heads. camshaft walk was my enemy at one time hahaha
i baught a pete jackson timing gear set and it came with it. iv even had cams walk out all the way to the waterpump and had to buy an aluminuununununm timing chain cover to make it stop. but they make stuff for them walking in also.

 

PS. they go BEHIND your camgear there should even be a machined surface for them there. my 400 had a machined surface if i rember correctly.....


http://www.youtube.com/watch?v=oXqvyivRMX0

 

okay this may sound stupid... but how is that usless(in this app) piece from summit going to stop the cam from moving towards the front of the block? it wont! you need a thrust button to do that... if cam walk was the problem that bearing would be usless however the $2 thrust botton they tell you to run would solve it...

timing set for roller cams are already machined for this...it is called a thrust plate... if you are running your roller cam without one and no thrust button you are just asking for it