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Discussion Starter · #1 ·
What? 69 TR6C XC***** (stock other than +.080 bore/pistons)
Sources of help? Correct workshop manual, bedside prayer, and some grumpy bastards on another forum.
Problem? Valve contacting pistons on hand rotation for inlet valves. Both at different rotation but approx BTDC.
Whats been done?
Started by checking top end for misplaced pushrods on the cam followers. no problem. properly seated. spin easy with dab o grease.
Nothing indicates valve stems are traveling too far due to excess material cut from head.
standard copper head gasket.
rocker boxes are correct for this model and ball pins seated etc

Gotta be valve train.
Suspected the intermediate (center) wheel had been placed incorrectly. Got out the manual and began reading. Replaced the wheel with correct alignment marks. Inlet valve clearence is correct now. Exhaust now contacts the piston BTDC firmly when the engine is turned slowly by hand. Reset the intermediate wheel 4 times and still get valve contact on either exhaust valve at approx the same point. Inlet is fine each time.

Is it possible for the cam pinions to be incorrectly set on their shaft?
Workshop Manual says, Sec B35 & fig B33 "..., and the camshaft pinons are located by means of the keyway directly opposite the timing mark." Damn the English. Why cant they speak Texan? Does this mean there is an alignment key behind the nut? I see nothing indicating the pinion is correctly or incorrectly set on the cam shaft.

Am I chasing the wrong ghost here? Pull all the pinions and start fresh? Can it be done w/out the extractor tool? Tired of seeing this thing sit in the garage and want to ride it/sell it.

any help appreciated.

respects all,
 

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yes, there is a keyway behind the nut, that keyway must be lined up with the stock timing marks (one centerpunch) for the stock placement of the intermediate wheel to be correct. Someone probably tried their hand at degree-ing in the cams for performance and then the wheel got pulled out and put back in wrong for whatever that other person cooked up timing wise.

it is kinda hard to pull the wheels and replace them without the correct pullers.
 

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I know this might sound stupid but did you check that previous owner didn't use off-set valve adjusters.This was a common way of increasing valve lift without changing cams.Worth a look.
 

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Discussion Starter · #5 ·
Frosty said:
I know this might sound stupid but did you check that previous owner didn't use off-set valve adjusters.This was a common way of increasing valve lift without changing cams.Worth a look.
valve adjusters are stock, but thanks much for the reply.
 

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Pops said:
What? 69 TR6C XC***** (stock other than +.080 bore/pistons)
Sources of help? Correct workshop manual, bedside prayer, and some grumpy bastards on another forum.
Problem? Valve contacting pistons on hand rotation for inlet valves. Both at different rotation but approx BTDC.
Whats been done?
Started by checking top end for misplaced pushrods on the cam followers. no problem. properly seated. spin easy with dab o grease.
Nothing indicates valve stems are traveling too far due to excess material cut from head.
standard copper head gasket.
rocker boxes are correct for this model and ball pins seated etc

Gotta be valve train.
Suspected the intermediate (center) wheel had been placed incorrectly. Got out the manual and began reading. Replaced the wheel with correct alignment marks. Inlet valve clearence is correct now. Exhaust now contacts the piston BTDC firmly when the engine is turned slowly by hand. Reset the intermediate wheel 4 times and still get valve contact on either exhaust valve at approx the same point. Inlet is fine each time.

Is it possible for the cam pinions to be incorrectly set on their shaft?
Workshop Manual says, Sec B35 & fig B33 "..., and the camshaft pinons are located by means of the keyway directly opposite the timing mark." Damn the English. Why cant they speak Texan? Does this mean there is an alignment key behind the nut? I see nothing indicating the pinion is correctly or incorrectly set on the cam shaft.

Am I chasing the wrong ghost here? Pull all the pinions and start fresh? Can it be done w/out the extractor tool? Tired of seeing this thing sit in the garage and want to ride it/sell it.

any help appreciated.

respects all,
My bet would be that the cams were not original, or the timing marks were not lined up correctly. Some aftermarket cams require modified pistons & springs. You do know that once the timing marks line up, rotating the engine will not let them line up again for a full 94 revolutions?
 

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Discussion Starter · #8 ·
oktr6r said:
My bet would be that the cams were not original, or the timing marks were not lined up correctly. Some aftermarket cams require modified pistons & springs. You do know that once the timing marks line up, rotating the engine will not let them line up again for a full 94 revolutions?
could be a hot cam setup. never met the PO. Hope I dont have to tear it down to find out.
yes re the 94 rev matching
thanks for the reply.
 

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Pops said:
could be a hot cam setup. never met the PO. Hope I dont have to tear it down to find out.
yes re the 94 rev matching
thanks for the reply.
You might be able to measure the lift at the lifters and compare that to stock lift specs. It'd require pulling the head and pushrod tubes, but that's not a big deal.

Next step IMO would be pulling the cylinders and seeing if you can read any numbers on the cams.
 
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