Posting for a friend with a 1984 CJ, 258, std. that he's rebuilding.
What's the spec for cylinder compression? He's getting 160 across all 6 cyls, which sounds pretty good from here.
He's putting a new fiberglas tub on his Jeep and might have a windshield frame from a Wrangler fall into his lap, which was offered to him as having a better wiper system than the CJ. Will this fit the tub without causing problems with his hard top? I gather that there may be bolt hole and vent issues, but since he's putting a new tub on anyway it might not matter. Will his existing scratch-and-chip-free windshield glass fit the Wrangler frame?
The windshield frame will work, but you will have to cut vent holes to match the defrost vents that CJ's use. Not too hard to do, and if they are ugly no one will see anyways. You may have to mix and match wiper motor arms to get it all to work as well.
The one done on small aircraft engines involves pumping 80PSI into the cylinder and reading the remaining pressure off a gauge. The results are given as 77/80, 76/80, 79/80, 80/80.
The compression is too high or the gauge is bad. A 'new' 258 is only supposed to have 150. (carboned up or shaved head?)
As mentioned, the vents are different on the frames if it is a 'stock' frame. If aftermarket they fit both but you 'really' have to check the post for the driver's side wiper to make sure it is in the right place and the sheet metal around it is not not bent. There are a pile of bad ones on the aftermarket. The result of the poor wiper arm post fit is a jam and a burn out of the motor or intermittent module smoke out with bent linkages.
I was given one also when I did my 'glass tub and it was already crapped out and sheet metaled over that hole to move it. I bought a new one and got the same crappie fit. I eventually had to cut the hole out of my old frame and move it over to the new frame to position it right after a couple years of messing around with washers and cursing when it died on the highway in the rain.
Tell him not to forget to ground the windshield frame itself! The hinges have this nasty tendency to not want to be ground points for the wipers about half way through bogs as I found out on a trip 1000 miles from home in a Nova Scotia bog with 3500 miles left to get back home.... Figured it out pretty quick but getting the rest of the way through that bog with my head out the door to see was messy....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
160 is very good. The spec is 150, but the real spec is that they all be within 10% of each other and that they be within a couple of pounds from one to the next.
Thanks all who replied. I've passed on your advice, with thanks. He's decided to go with the `glass CJ windshield frame, to reduce installation hassles.
Lee
Mike Roma> The compression is too high or the gauge is bad. A 'new' 258 is only
Unless he is going to drive topless or with a hard top only, he cannot use a 'glass windshield frame. Didn't even think they sold them anymore. Most places stopped selling them when they figured out they don't work.
If he uses a soft top or bikini top, the aerodynamic lift factor will pull the top of the frame clear off the glass.
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