1970-Bronze

A while back I cracke a water jacket in the driver's head. I started tearing down the top end and I just got around to dropping the pan to see if I need a complete rebuild.

So, I dropped the pan and found large hunks of plastic in the pan. I then dropped the oil pump and it's full of more hard plastic. Any ideas? Maybe that explains why I had low oil pressure. :confused:

The rear main bearing looks fine with very little wear - no brass showing. So I think I'll be buttoning it back up and only doing a top end rebuild.

Sharky Guam

It could be from the timing gear.....

Bullshark

Quote: "It could be from the timing gear....."


:iagree: That's my bet! Been there done that :yesnod:

Bullshark


[Modified by Bullshark, 5:14 PM 5/23/2004]

Eddie 70

That hard black plastic could be carbon buildup that has broken loose. Or so that was what was once told to me. I found the same thing when I tore my engine down. I also found it in the pan and on the low spots on top of the head.

jyounane

:iagree: Been there, done that, fix it NOW!!! or else things can get expensive later.

1970-Bronze

Definitely wasn't carbon. it's definitely plastic. Looks aged and yellowish brown in color.

BEBOP138

It`s your old factory plastic timing gear.... found the same thing when I tore down my engine---the previous owner had replaced the gear and chain but never bothered to check and see if any pieces had been sucked into the oil pump, they were laying on the bottom of the screen, sounded like a baby rattle when you shook it---check all over some of the chuncks are pretty small!! :chevy

1970-Bronze

Ok, I'll be pulling the cover and checking. Lot's of chunks in the old pump.

I've got a new oil pump. I'm just wondering now whether I should use the high pressure spring or the standard one. :confused:

Smokehouse69

Personally, I'd go back with the stock type spring. A high pressure spring won't make up for badly worn engine. If everything is in adequate condition, then a stock oil pump will provide plenty of oil pressure.
I'd really suggest checking your cam and cam bearings, cam bearings are notarious for being the cause of low oil pressure.

BlueL36

The teeth on the factory cam gear was covered with nylon to (presumably) keep noise down. But they only lasted 60K miles. When the nylon gets brittle and comes loose, problems can range from erratic timing to bent valves or worse if the chain jumps a tooth. Replace it with a new, non-nylon timing gear set. A bit noisier, but bulletproof. Check your lifters, cam, and bearings for scoring or pitting- it's one of those necessary "while you're there" things. Also, clean the oil pump out really well. Good luck!

vettfixr

Everything said here was good but check one other thing. On some of the oil pump assemblies the collar that connects the distributor to the oil pump is plastic. Most of the high performance units use a steel sleeve. Just check that the oil pump collar isn't shattered. Good luck.

mrvette

vettfixr, you just gotta be kidding, plastic in the oil pump drive???

then freaking IDIOTS.....tell you what, no one will ever convince me about any noise issues or any other reasons why using plastic in any spot internal on any engine is a good thing......it's pure BS, and GM got (getting??) away with that for decades, and GM aint't the only one either, I know Chrysler used to do it also,,....suspect Ford did too.....

I allways use a Cloyes double roller for replacement, without exception, and knock on wood have never had problems again after that....

plactic.....what brand of IDIOT came up with that......yeh, he's a real BSME ok....

GENE

carnut114

I have seen oil pumps that had the plastic slip on sleeve. I use only the one's with the metal sleeve that is pinned on. The plastic can break and also if you take the distributor off sometimes it can come off.

Eric

Paul L

This is the gear with nylon teeth. Note that the gear itself is steel but the teeth (once white) are yellow in colour. And very brittle. This one was intact but I replaced it with a Cloyes unit.






[Modified by paul67, 10:26 AM 5/24/2004]

Fevre

I had the nylon gears go in an Olds one time and paid $400 to get it replaced. Week or 2 later it spun a main bearing. Guy says prolly got nylon in the oil pump and would not warranty it. :mad Replace your oil pump ($20 -$50) along with the timing set. Also get a 1 peice oil pan gasket, less prone to leaks.

MELVIN

its the oil pump plastic sleeve, My 68 had the same plastic in the pan. Removed the oil pump, and yep, the pastic collar was gone.


I stay away from any high pressure, or for that matter, high volume pump on any stock, or slightly modified engine

vettfixr

Yep, they made them with plastic sleeves. Makes ya wonder doesn't it.
:crazy:

markdtn

Just to be clear, the drive itself is not plastic. It has a plastic collar that holds the oil pump outputshaft to the driveshaft that goes between the distributor and the oil pump. Even if it broke, I doubt it would clog the pump. The timing chain, however, can make a mess.

Paul L

The sleeve is a possibility. The pic shows the GM version. But it should not be hard to distinguish between teeth and parts of a small cylindrical object.



And the shaft at the upper left side of this pic is where that retainer/sleeve is installed. I was reminded by a friend AFTER I had installed the oil pump!! Let's try that again.





[Modified by paul67, 2:15 PM 5/24/2004]

Wrencher

The little sleeve is just to hold the shaft to the pump during assembly. I keeps the shaft from falling out of the pump if the engine is rolled over, or pulling out with the distributor.

What you found is deffinitely timing gear material. Plastic over aluminum usually to make a quite gear and chain set. Put in a double roller with a steel gear and your done. Your lucky it didn't ruin the pump, and you should check it over close. As inexpensive as they are, I'd just replace it.

Hans