Cam alignment question

[HamzahF]

Hi y'all

I have this little gremlin in my trusty old FJ70 with the original 3F. The motor has around 273000 KMS on it and does every thing great apart from idling. Tweaked carb to nice tan plugs and everything else to spec, threw in a new dizzy after a suspected bad bearing, timed it to spec, did leak-down tests, no problems there, no vacuum leaks and despite all this, it doesn't quite idle the way it should. I got around to doing the valve lash and set # 1 to TDC , checking the valves specified in the manual. To my surprise, two of those 6 valves to be checked with # 1 at TDC were depressed into the open state all the way in. Same was with # 6 at TDC, with two valves depressed open on that inspection run as well.

Does this decisively point towards a misaligned cam shaft? If i want to drop in a new one, can anyone give me a run down of the correct procedure. Is it to be put in place with the marks aligned on the cam and crank gears with # 6 at TDC as it says in the manual? Are there any other bits to look out for?

Any word on this would be greatly appreciated. It gives me chills thinking that i drove it such for around 4-5K KMS :whoops:.

Regards.

 

[roscoFJ73]

I dont have a 3F manual in my grasp ,but are you sure you have the procedure correct.
If you had valves open when they should be closed ,you would have more than a rough idle problem.


When my 3F got to about 290000klms I found the cam shaft to be totally worn out and the valves could no longer be adjusted accurately

 

[HamzahF]

^^

Thanks for the reply roscoFJ73.

Yeah, what you say makes sense, but id have to be a complete boob for not being able to set #1 at tdc.

Maybe the cam alignment is off by a few teeth, and causes those two valves to remain open?

Apart from this, whats the correct way to replace the cam? #6 at TDC?

Cheers

 

[HamzahF]

42 views and only one reply?

C'mon gents, help a guy out some!

 

[PhrogsPhorever]

Well, not as many 3F in this forum, maybe the 60 series, maybe 80 series forum will have some more 3F stuff.

Silly question, are you working off the FSM?

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[cruisers75100]

Have you done a compression test on the ol girl lately?

I would be doing that , just as a process of elimination! If one cylinder is down on compression it will idle poorly....

Cheers

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