Topic: Message #1126604

[Snowtoy]

I think I'm confused...  drop the pan??

When setting correct initial cam timing, the crank pulley can only be in one position.  If I set the timing mark in the crank pulley to zero on the oil pump tab, and I know that number cylinder is firing TDC with mark on crank pulley sitting at zero on the oil pump tab, I set the cam sprocket dot at 11:55 with cam sprocket keyway at exactly 12 o'clock, with the guides, tensionor, installed, and chain on the both sprockets.  I rotate the cam sprocket about 10 or 15 degrees retard and advance, again align the cam sprocket with the dot at 11:55 by slowly rotating the crank pulley, check that the crank timing mark is still sitting at zero..... how can anything else be "possibly" off??   

If the chain is off by 1 link, as I remember it's about 4 or 5 degrees cam timing either retard or advance.  If I rotate the crank to number 1 cylinder firing at TDC, looking at the cam sprocket with the dot at about 11:55, and the KEYWAY on the camshaft is NOT exactly at 12 o'clock, like 11:55 or 12:05, then the chain is off by one link and it will be obvious. 

The two bright links or dark links are just to correctly align the dots on the crank sprocket and cam sprocket while installing the chain, which has 48 links.  If the chain is correctly installed initially on the cam and crank sprockets, chain link number 24 will be sitting on the dot on the cam sprocket and chain link number 48 will be sitting on the dot on the crank sprocket.

But... since I am a loooongg waayyss from an "engine builder", and I don't get to practice too much on my Toyota trucks, I will happily defer to any of you experts out there.

Gnarls.

"Installing correctly" is the issue.  I am by no means an expert builder, I have only cracked open 12 Toyota engines over the years from simple repairs to full rebuilds, w/10 being the 22r series.  Of the 10 22's I have been into, 3 had the t-chains installed incorrectly.  One was installed w/no regards to the marks, the owner said it made a bang sound when he tried to to start it after he did the chain, had to redo the head due to bent valves.  The second one was an '84 and the t-chain was upside down at TDC, either the installer had the engine 180* out of timing when he installed the chain, or thought the chain manufacturer made a mistake and doubled up one set of links.   It ran but not well enough to set the timing, installed the chain correctly and it ran fine.  The third one ran fine but in order to do so the dist. had to be clocked so far counterclockwise the person who installed the chain cut the end of the adjustment arm off to be able to access the retaining bolt hole, then used a large washer/spacer to hold the dist. in place.  You would have thought that when he was taking a hacksaw to the dist., the thought he was doing something wrong should have crossed his mind.  After I installed the dist. correctly it wouldn't run at all, so I figured the chain had to have been installed wrong and that is why the installer had to modify the dist.  I pulled it down and at TDC the cam gear aligned with the link on the chain, but the crank was off, I reinstalled the chain and it ran/timed correctly w/the dist. in its correct place.   Based on the info 93REDCRAWLER's gave, it seemed like the t-chain wasn't installed correctly by the builder of the "new rebuilt" engine.  With the valve cover off he could only see the cam/chain marks, IIRC from replacing rod bearings, there is just enough of the crank gear sprocket exposed with the pan off that he might be able to see the bottom timing marks.  I have never tried it this way, but if he could see the timing marks, it would save him from having to remove the timing cover.