Cam bearings

Webers, Cam selection and Ignition upgrades.

Moderators: BOBLOOK, AE25, pufito18

Estebot
Posts: 52
Joined: Thu Jun 20, 2013 10:41 pm
Location: Reno, nevada

Cam bearings

Post by Estebot »

Does anyone wnow what the clearance should be on the front cam bearing? I keep wiping out distributors and cam gears.
The groove is supposed to oil the dist gear but something isn't right. Or oil is foaming? Not sure.
Estebot
Posts: 52
Joined: Thu Jun 20, 2013 10:41 pm
Location: Reno, nevada

Re: Cam bearings

Post by Estebot »

Or thinking its the extra load from high volume oil pump?
bruce
Posts: 8
Joined: Sat Jul 20, 2013 11:52 am

Re: Cam bearings

Post by bruce »

What duration camshaft are you running? Did you modify the oil pump for higher flow?

I've got a 3TC engine manual that might have the clearance specifications, but won't be able to check till next weekend.
Estebot
Posts: 52
Joined: Thu Jun 20, 2013 10:41 pm
Location: Reno, nevada

Re: Cam bearings

Post by Estebot »

It has a high volume oil pump. Maybe too much load at high rpm. Turning 9000 while racing.
Gonna run stock oil pump with a tiny shim. I feel like its too much drag on the gear at rpm with that pump.
We'll see.
KE20Rally
Posts: 15
Joined: Tue Oct 29, 2013 11:42 pm
Location: Perth, Western Australia

Re: Cam bearings

Post by KE20Rally »

Hi,

I destroyed 2 crower cams and resulted in 2 engine rebuilds from this issue that I have now resolved!

This issue dates back to the early 70's when Toyota(TRD i beleive) had the same issue when they used the 2TC in formula atlantic, I was lucky enough that my friend who assisted me with my 2 rebuilds was racing in Adelaide Australia when he saw an Australian built Cheetah formula car racing with a high reving 2TC. My friend approched the elderly gentleman who was driving the car and asked him if he had any camshaft issues, he answered with "have I had issues? yes many!" so the following is what I have done to rectify the issue and in what I believe is the order of importance:

1. install an oil squirter directly on the distributor gear, drill and tap a 1/4" npt thread into the block, make up a squirter and tap of the oil pressure switch, my squirter is 40 thou from memory (i believe this is the main thing that TRD did and was the information given to me from the gentleman in Adelaide)

2. I had a bronze distributor gear machined up, alot of information is out there regarding bronze distributor gears. (small note, my machinist said the gear was imperial on the Schneider cam and being on a Japanese engine, the distributor drive should be metric, he could not confirm this, so he machined the gear to suit the cam)

3. ZDDP additive, again there is alot of info on the net as this has been removed from modern oils.

4. Changed from a Crower Cam to a Scneider Cam.

5. Changed from a high volume 3TGTE oil pump to a brand new standard Toyota oil pump.


As you can see I have made many changes, my first crower engine died after run in and 1 dyno session, I rebuilt it with another Crower cam, and changed back to a standard oil pump from the high volume, this lasted a little longer, it survived a dyno session and half a rally, which equates to about 2 hours of hard driving, the 3rd engine that has all the modifications above has had 1 dyno session, 3 rallys is still going strong and the distributor gear is checked regularly and looks fine.

Please ask any questions you would like and I will do my best to answer them.

Cheers,

Pete

Edit, a couple of pictures showing the location of my oil squirter on a spare block:
Oil squirter hole small.JPG
Oil squirter hole small.JPG (219.2 KiB) Viewed 16840 times
Squirter close up small.jpg
Squirter close up small.jpg (245.54 KiB) Viewed 16840 times
Attachments
squirter oil feed.jpg
squirter oil feed.jpg (216.01 KiB) Viewed 16780 times
Last edited by KE20Rally on Mon Nov 11, 2013 7:06 am, edited 1 time in total.
Toyota1515
Posts: 784
Joined: Fri Aug 09, 2013 2:59 am

Re: Cam bearings

Post by Toyota1515 »

If you have a billet cam or anything non OEM Regrind your dizzy gear will go out very quick, unless you use a bronze gear on the dizzy.
SF5 FOZZY
superhoeper
Posts: 5
Joined: Mon Sep 30, 2013 2:44 am

Re: Cam bearings

Post by superhoeper »

Hey there. I saw this topic and now I have some questions. Im planning on building up a 3tc in the near future and I was planning on getting a crower cam. My question is, are the dizzy gear and cam bearing problems caused from being a high-reving engine or the aftermarket cam or both? I just want to know if I'll need a bronze dizzy gear with a turbo 3tc with a crower cam with a red line of about 6000?
KE20Rally
Posts: 15
Joined: Tue Oct 29, 2013 11:42 pm
Location: Perth, Western Australia

Re: Cam bearings

Post by KE20Rally »

superhoeper wrote:Hey there. I saw this topic and now I have some questions. Im planning on building up a 3tc in the near future and I was planning on getting a crower cam. My question is, are the dizzy gear and cam bearing problems caused from being a high-reving engine or the aftermarket cam or both? I just want to know if I'll need a bronze dizzy gear with a turbo 3tc with a crower cam with a red line of about 6000?
I have 2 failed Crower cams as discussed earlier, was it from revs, valve train harmonics, camshaft, zinc missing from the oil, high volume oil pump, poor gear lubrication? I couldn't honestly tell you the exact cause, I wouldn't risk it as when the cam fails you need to pull the engine down and at the very least you will need to hone the block as all the hardened metal fragments get thrown into the #1 cylinder, then you need a new Cam! Spend the $200 get a bronze gear made to suit your cam, add an oil squirter and know you won't have to pull your engine and rebuild it a second time due to a failed camshaft.

Cheers,

Pete

Edit, a couple of pictures showing the result of using a standard dizzy gear with a crower Camshaft..... X 2, up to you if you want to see if keeping the revs below 6000rpm will prevent failure!
crower gear.jpg
crower gear.jpg (173.16 KiB) Viewed 16780 times
Attachments
crower close up.jpg
crower close up.jpg (162.15 KiB) Viewed 16780 times
Last edited by KE20Rally on Mon Nov 11, 2013 7:12 am, edited 1 time in total.
Toyota1515
Posts: 784
Joined: Fri Aug 09, 2013 2:59 am

Re: Cam bearings

Post by Toyota1515 »

I also find that when new cam bearingf areinstalled the cam that was therr didntfi crrectlly ant i need to massage the bearings to make the cam rotate free like is supposed

Only engine i need to do this is in the damn 3tc or 2tc when new cam bearings are installed, why? I h ve no clue, maybe aftermarket bearings are not perfect who knows!
SF5 FOZZY
KE20Rally
Posts: 15
Joined: Tue Oct 29, 2013 11:42 pm
Location: Perth, Western Australia

Re: Cam bearings

Post by KE20Rally »

So far the cam bearings that come in my blocks have been in good condition, my machinist recommended to leave the old ones in the block as they can be a pain in the butt to replace and I am assuming that is why you are having the clearancing issue. He has a good reputation over here so the old bearings stayed! (had a lot to do with the development of the fastest door slammers in Australia http://www.zapsrat.com.au/ )

Pete
Post Reply