Forum > Pinto FAQ
2.0 valve stem height specs?
pintoist:
I never have chatted on forums before, but I need to cool off a bit & would like to find an answer to my question.
I've been working on a 1973 Runabout w/ a 2000cc 4spd (it was my daily driver). I had the head "rebuilt" 5K ago.
After removing it & finding multiple cracks (had coolant in the cyl.s & oil) I decided to use its valvetrain on another head after checking the guides, grinding the seats & doing all the other necessary work; making a long story short, all the valves were un-useable(stems well worn out of spec., a few were bent- among other things), the followers from both heads needed replacement, both sets of springs were worn out, and both cams were worn out (journals & lobes on the one out of the "rebuilt" head/lobes only on the other one).
I got all the needed machine work done at a local shop & I'm going to use a vernier cam sprocket. I ordered the following parts from Burton Power: Kent FR30 cam, followers & performance valve springs (75lbs@1.500") for lifts over .460". They sent me the wrong springs, so I'm doing other work while I wait to hear back from them.
In my "free time" I've looked for the valve stem installed height specs, but I haven't had any luck finding them. The only suggestions I've found are to use dykem, assemble, grind & repeat as needed. I've also been told to "put it together & run it." The first suggestion will be very time-consuming, & the 2nd wouldn't be prudent because it wouldn't be possible to accurately degree-in the cam & have the timing consistent at each cylinder(mechanical lash adjusters).
If I had the factory stem height specs it would save a lot of time & aggravation. Any help is greatly appreciated. Thanks!
Wittsend:
For anyone who read my previous rely, I am amending it. I was under the assumption that the 2.0 engine set the cam wipe similar to the "lash pads" the Datsun L-series engines used. Sadly, apparently not.
That said, once the tip height is known could one simply put the assembled head (sideways, minus the cam) on a surface grinder and with careful action quickly bring the stems to the proper height? It would seem to be a lot faster than constantly pulling the valves and grinding the tip.
turbopinto72:
I have been dealing with this issue for a while. My over sized valves were also about .50 long. I started taking off .10 per intake and ex valve and started checking them. The " goal " is to make sure the rocker " pad " hits on the pad portion of the rocker. Not the end, not the beginning but dead center. There is very little room on either side of the "pad" once you have it working properly. I use a real weak spring and set the head up one valve at a time, spin the cam and use bluing on the pad to see where the cam lobe is hitting. I took .50 off the intake and .70 off the exhaust. ( again because these valves were long to begin with )
This has taken me some time to do, but you DO NOT want to put the head together with out getting this aspect right or you will ruin your cam real fast. ..
pintoist:
First of all, I'd like to thank the fellow pinto-lovers who've provided me with responses thus far. It's really appreciated!
Yesterday I got as far as applying the dykem & assembling the head. Very soon I'm heading out to place another international call to Burton- this time using the "customer service" number provided on their site. I know now that there are 6 hrs. difference
between CST & England-Time. So the earlier I call, the better.
I also emailed a inquiry to Kent Cams, but I'm waiting for a response. If I find anything out I'll let everyone know. I also had to amend my original post because the cam is actually a "FR30 Sports Torque" grind.
Wittsend:
First of all, all the best in dealing with the overseas communication. At least you know and understand what needs to be done.
As I mentioned above the Datsun L-Series engines had a small disc (I believe they called buttons). One side was slotted to receive/align the cam follower and the other indented to sit on top of the valve tip. This piece was held in place by the valve retainer that had a built in collar to contain it. The adjustments that are needed were simply done by swapping out different sized buttons. When my (Datsun) friend got his cam at Racer Brown's we bought the head along, they used a light spring, Dykem on the follower and button and quickly determined the button thickness needed. The way the 2.0 cam follower is designed it seems a rather laborious task. But, I imagine the follower movement rate increases rapidly as the cam rises to the nose and you need to be very careful - especially if the cam has higher lift.
I'd be curious to know if the factory tip height is even applicable to a cam with more lift? It would seem to be necessary to use more of the followers surface area as the valve was pressed down further. Maybe that is why you are having trouble finding the spec. published???
Navigation
[0] Message Index
[#] Next page