Hey mc posting for a customer, he's on his 3rd dist. the 'helical' gear keeps sheering cam looks good timing has been set at 5°btdc engine has 5000 completely rebuilt any ideas what can cause this? I told him he has to drop his pan and get the chunks out.  Says the top end is in synch with the bottom end the chain has 5k as well.  He bought a transmission off me and bought two distributors in the last week.

The distributor isnt the problem its happened to 3 different ones, something is causing the cam to not be in synch obviously though.  He gets paid today i just wanna make sure he spends his money wisely.

I've swapped cams a few times without removing the head just loosen the bolts in sequence evenly then put back together in sequence evenly. Left exhaust, intake and junk just as it sat. Had no ill effect due to it.

If he has an after-market cam, especially an overseas one, the cam gear may be ground off-pitch or hardened incorrectly.  The cam bearings/saddles could be loose or bent cam, causing wobble. Head could be warped and saddles not aligned any more, so cam runs slightly down-hill or up-hill at the cam snoot.  Never seen this on a Toyota before, but have on USA engines.  Turn engine over (not running)and check run-out of the cam in several places and plastigage the cam bearings/saddles, top, sides, and bottom. Good luck.   

engine has 5000 completely rebuilt

I have seen newly built engines that never had the oil galleys cleaned out.  I guarantee you thats the issue.  onle takes a 1/4 inch drill bit screwed in by hand to clean it out.  needs to be able to go all the way into the intake side headbolt passage.

I have seen newly built engines that never had the oil galleys cleaned out.  I guarantee you thats the issue.  onle takes a 1/2 inch drill bit screwed in by hand to clean it out.  needs to be able to go all the way into the intake side headbolt passage.

I'm a long way from an engine builder so I'll defer my comments to the experts out there...

There are 3 oil ports that feed the 3 cam journals.  It would seem odd that one or all of those ports would get plugged up.

Since all 3 are feed from a common oil galley, wouldn't there be other issues with lubrication?  If the cam bearings were worn so badly that the camshaft could actually move enough to cause the 2 gears to not mesh and crash, the engine would not be running right, lots of noise, and should be very noticeable.  With the crank turning the cam gear, how could the camshaft seize up and stick?

By the way, the oil ports in the cam journals on my 22RE factory head are about .220" in diameter not 1/2".

Gnarls.

I'm a long way from an engine builder so I'll defer my comments to the experts out there...

There are 3 oil ports that feed the 3 cam journals.  It would seem odd that one or all of those ports would get plugged up.

Since all 3 are feed from a common oil galley, wouldn't there be other issues with lubrication?  If the cam bearings were worn so badly that the camshaft could actually move enough to cause the 2 gears to not mesh and crash, the engine would not be running right, lots of noise, and should be very noticeable.  With the crank turning the cam gear, how could the camshaft seize up and stick?

By the way, the oil ports in the cam journals on my 22RE factory head are about .220" in diameter not 1/2".

Gnarls.

those passages are fed by a common galley pressured through the intake side headbolt holes.  I have seen blown engines that had one or all three plugged and also the crank galley's would be plugged up BUT it comes down to which one starves first. 

the cam journals are aluminum so if they starve the cam eats into them quickly.   My dad had a 1967 F800 gas burner that starved of oil in the rear cam journal of an iron block. that rear bearing seized and the cam snapped into three pieces. 

I know the size of the hole is 6mm or .240"  that 2 was supposed to be a 4. 

He hasn't had any money to do anything.  I want to go and check his engine out but i have been selling more than 5 parts a day on ebay and i put a lot of tlc into packaging for customer satisfaction
He says theres no play on the cam but i want to check everything out.  The previous owner had referred this info to him, I'll have to find out if he is still in contact with them for more partiulars of the engine specs.

He hasn't had any money to do anything......

I'm very familiar with that issue since starting my rebuild! 

Gnarls 

Tell him to pull the valve cover and make sure nothing is screwed up/cocked sideways (Yes I had the cam shaft sprocket sideways once and it made installing the dizzy a PITA). After he checks it's all in alignment is the distributor sliding in easily? If not then something is wrong.

it almost looks like the gear isnt lined up. like its a gear for a 22R being used on a RE. they have different depth.
that 12mm head bolt that has 8.8 in the oil must be about to bounce out. it shouldnt be above that oil pool at all.

The cam gear for the 22R and 22RE should be identical.

This cam gear is damaged and has parts of teeth missing and fractures at the addendum.

NO BUENO!!

I would replace the gear and very carefully engage the distributor. Rotate and examine the synching of the both gears and see if there are any issues with alignment or excessive or insufficient gear engagement.

What caused that should be checked out carefully. 

Is the cam sprocket bolt torqued correctly to spec?

Was the cam gear defective and had fractures or a porosity problem at casting?

Were the helical gears cut incorrectly and the base circle diameter too large?

Is the lateral and perpendicular alignment off - Why?

Is the camshaft slightly longer at the gear mount?

Is the camshaft sprocket thicker at the mounting hub than it should be?

Is the hole for the distributor in proper alignment and the distributor boss on the head the correct depth?

I'm sure we have noticed that much of the aftermarket parts are coming from China.  There are about 12 foundries in China that make millions these various parts. Obviously the quality can be suspect with every part. Over the years I've had issues with almost every other part I've purchased at Autozone, O'Reilly's, Pep Boys, etc.  On parts like gears, the new or replacement parts should be mic'd to compare with original or ones being replaced.  Reputable suppliers like engbldr, 22RE Performance, and LC Engineering, have narrowed down their quality sources because they are a small business in a niche market and cannot afford to sell crap.

Of course all efforts to buy quality parts doesn't mean you are guaranteed to always get quality parts.

The damage to the disty gear as shown before would indicated that metal pieces most likely have dropped down into the oil pan, this could cause enough damage to bearings, cylinder walls, or plug up oil galleys and require a complete engine rebuild.

I would not trust and verify.

TJMWO 

Gnarls.