Welcome Visitor! Please take a few seconds and mudboy
New Member
- Joined
- Mar 6, 2008
- Messages
- 30
- Reaction score
- 0
- Points
- 0
- Age
- 42
- Vehicle Year
- 1987
- Make / Model
- Ford
- Transmission
- Manual
I currently have a 91 explorer that I'm up in the air about what I'm going to do with it. Since I got it 1 year ago it has always had an upper end "Tick". It will tick about 10 times and then quiet up for a few seconds and then come back. From what I understand the rockers in these motors suck and wear out, i'm guessing thats what I have going on, or a lifter. It didn't bother me too much at first but now it's getting to the point of a an occasional miss about every 5 seconds or so. I really want to get a set of heads for it and call it a day, but there are a few things I have to do to prove to myself it's worth dumping money into.
From what I have read the oil pressure gauge is not actually a gauge, it is a digital on or off. This does not help me diagnose if the bottom end of the motor is goo or not. I have to get a real gauge to determine where my oil pressure is. My question to those with aftermarket oil pressure gauges is, on the 4.0 OHV, what pressure should I be looking at cold and at temp? At what poiont would you consider the bottom end no good and not worth investing money to the top end of the motor?
The second thing I have to do is find out the rest of the bottom end is any good by performing a compression test. I understand that if there is a cylinder with 10% less than the others then it is time to put some oil in the cylinder to see if it bumps the compression up pointing at faulty rings. My question on this is at what pressure would you consider all 6 cylinders no good? So lets say my readings where 90, 95, 91, 94, 97, 92 would that be too low?
If both of them check out to be good the I'm going to order a set of heads. My motor is a 91 and I know that I read somewhere at sometime, a different newer casting will bump the compression ratio up some. I'm not sure what casting number that is. I'm also curious for those that have done the higher C/R heads and 49-422-8 cam, was it worth it over4 the stock set up. I know these OHV motors are hard to get any real numbers out of but it would be nice to have a little more balls to the truck. Thnaks in advance
From what I have read the oil pressure gauge is not actually a gauge, it is a digital on or off. This does not help me diagnose if the bottom end of the motor is goo or not. I have to get a real gauge to determine where my oil pressure is. My question to those with aftermarket oil pressure gauges is, on the 4.0 OHV, what pressure should I be looking at cold and at temp? At what poiont would you consider the bottom end no good and not worth investing money to the top end of the motor?
The second thing I have to do is find out the rest of the bottom end is any good by performing a compression test. I understand that if there is a cylinder with 10% less than the others then it is time to put some oil in the cylinder to see if it bumps the compression up pointing at faulty rings. My question on this is at what pressure would you consider all 6 cylinders no good? So lets say my readings where 90, 95, 91, 94, 97, 92 would that be too low?
If both of them check out to be good the I'm going to order a set of heads. My motor is a 91 and I know that I read somewhere at sometime, a different newer casting will bump the compression ratio up some. I'm not sure what casting number that is. I'm also curious for those that have done the higher C/R heads and 49-422-8 cam, was it worth it over4 the stock set up. I know these OHV motors are hard to get any real numbers out of but it would be nice to have a little more balls to the truck. Thnaks in advance
