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Q: Breck and Brenda Johnson wrote:HEY MARK, GOT A QUESTION FOR YOU. I HAVE 79 FJ40 AND WHEN TURN RIGHT I HAVE A JERKY FEELING COMING FROM THE RIGHT FRONT END I HAVE REPLACED A MALFUNCTIONING CALAPER AND REGREASED THE HUB BUT I STILL HAVE THAT JERKING I THE FRONT WHEN TURN RIGHT. ALSO IT SOME TIMES WON'T ROLL BACKWARDS WHEN ON A INCLINE MY UNCLE AND I OWN 4 CRUISERS AND WE REPAIR THEM OURSELVES BUT THIS ONE HAS GOT US STUMPED WE ALSO HAVE JACKED UP EACH SIDE INDEPENDTELY AND THE WHEELS TURN FREELY. A: This does seem a bit odd. Considering all of the sypmtoms you have described, the only thing that comes to mind right away is that you may have a broken birfield. While normally a broken birfield joint will interfere with the rotating of the wheel or the steering, or both, to the degree that the rig is disabled, it is possible for the results not to be that severe. If the joint is broken, the pieces and debris will bind up and cause the behavior that you have in your rig (and often much more severe problems). Does the rig function if 4wd correctly? Try jacking up the wheel in question with the hub engaged, and the rig in 4wd and in gear. Try to spin the wheel. If it does, then that's a sure sign that you have a problem there. If it doesn't spin, then try turning the steering wheel to different positions, and see if the wheel will spin at any point. Try it in both directions. Listen for any unusual sounds as you do so. To be honest, since you really can not apply the kind of resistence or torque to the system that it encounters when driving, i would not be sure that the joint is okay, even if it passes the quick "test" Particularlly since the problem seems to be intermittant. The only way to be sure is to remove the wheel, hub and spindle, pull the axle, and inspect the birfield. Although I have never encountered this, it may have a "partial failure" or cracking of the outer cage of the joint, which is only causing binding under certain conditions. If so, it WILL fail if subjected to heavy loads. If you (or a previous owner) have suffered a birfield failure at that coener in the past, there may be a small fragment of the original joint still in there that was missed when the debris was removed. This may be getting caught in the joint, ot between the joint and the housing. Let me know if this is in fact the problem. Q: Richard Lok wrote:I read somewhere about a conversion where the engine compression on a 2F was raised to about 9.5:1 with the addition of a cylinder head from an F engine. Is/was there any validity to this claim and if so do you know any details about the conversion? thanks A: This is a valid claim. I have two different 2F engine running in this configuration myself. Using the earlier 2F shortblock configuration (domed pistons), and the smallest F engine combustion chambers ('68-'72 with flat top pistons) you will see about 9.0:1-9.3:1 on a stock displacement engine. Using the later F head (which came off of the domed piston F) you will see a little less compression (in the 8.5:1-9.0:1 range). Both swaps will see a little higher compression if you have a 2F shortblock that has been over bored, producing more displacement. With the late model F head which has the 2F oiling passages for the rocker arm assembly, it is virtually a bolt on swap. There is a small bit of work to do at the rear of the head to match the 2F style water passages, but this is very minor. With the earlier head, you will have to arrange to supply the oil to the rocker arms, as these heads do not have the oiling galley that the 2F does. An oil line similar to the one employed in the F engine can be fabricated, and the F engine rocker assembly used. I have one of each style on my rigs. Personally I find that the later head provides all the compression that is realistically usable on the pump gas that is available these days. In order to run decent timing advance, premium is a must, and when I anticpate heavy loads (tralier towing, or mountain travel) I will add a little octane booster. The power gain is very noticable. This is a mod that I personally like quite a bit. To really take advantage of the compression, you will want to use headers. This combo works well with a aftermarket cam as well, as the higher compression offsets the slight loss of pure bottom end torque that many "performance" cams cause, and it really make the mid range and even top end power. Send your questions to Mark at cruiser@rockcrawler.com |
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