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View Full Version : 2.8 problem, flat cam lobe?


philofab
11-13-2007, 12:10 PM
Hi, I'm new to this forum but I'm active on FSB and Race-dezert. I just bought a 85 ranger 4x4 that I'm building into a chase/prerunner machine. The engine has a wierd problem. I seem to be getting a popping noise (almost like an exhaust leak) but it's not from the exhaust. The truck is bone stock except the air pump is siezed and has no belt on it. I'm fairly sure it's leaking compression into the intake. I did a compression test and I got this:

1:125
2:130
3:125
4:120
5:125
6:110

It is possible I have a bad cam lobe? I'm going to pull the valve covers tonight and check that the rockers are moving visually. After that I'll disassemble the top end. Any ideas?

Tumbleweed
11-13-2007, 12:54 PM
You might want to check valve clearances first. The 2.8 has solid lifters so the valves need to be adjusted every year or so.

philofab
11-13-2007, 02:55 PM
Anywhere online show how to do that? I don't have a book for this truck and I'm more used to 302/351 roller valvetrains.

skippy
11-13-2007, 06:15 PM
Anywhere online show how to do that? I don't have a book for this truck and I'm more used to 302/351 roller valvetrains.

the auto parts stores have the haynes ranger/bronco book,it's covered in there.just curious,how many miles on the motor?might need a valve job.

Tumbleweed
11-13-2007, 07:01 PM
Autozone has the information on valve lash adjustment free online, I'll try to put the link to it here, copy and past this and it should take you to the valve information. http://www.autozone.com/az/cds/en_us/0900823d/80/0f/83/87/0900823d800f8387/repairInfoPages.htm

philofab
11-13-2007, 08:07 PM
The engine has 103K on it. It has been parked for the last 6 years. I'd like to get this engine going to drive it for a while but if I have to spend to much money on it I'll just put my spare 302/C4 in it. It will be needed with the 35s and D44/9" setup.

philofab
11-13-2007, 08:55 PM
Well, I just took the driver side valve cover off. It's nasty under there... a lot of sludge buildup. The #3 cyl has a messed up cam lobe for the exhaust, it's adjusted all the way in and has about .250 clearance... just a little past factory specs j/k. Tomorrow I'll have to call on getting the heads redone and a new cam. Yay.

skippy
11-13-2007, 09:23 PM
Well, I just took the driver side valve cover off. It's nasty under there... a lot of sludge buildup. The #3 cyl has a messed up cam lobe for the exhaust, it's adjusted all the way in and has about .250 clearance... just a little past factory specs j/k. Tomorrow I'll have to call on getting the heads redone and a new cam. Yay.

are you sure?thought compression was down in #6 cyl.are you jacking engine over slowly by hand?if you get a cam you got to have new lifters too,getting the heads done is a good thing,the valve seals deteriorate fast in these motors,mine were gone at 150000miles.exhaust valves were pretty rough too.i used the book and remote starter to jack engine but never got the clearance right until i jacked it over by hand,kept getting large gaps.anyway it purrs now.good luck.

philofab
11-14-2007, 09:31 AM
The valve isn't opening on #3 so it won't affect compression. I need to decide if I'm going to fix this motor... For the price of the parts I could probably get a nice 5.0 H.O. EFI and put my frest C4 behind it. Thats the plan anyways so I might be better off doing right now.