compression test

[cindy8653]

Does anyone know if the Equus 3614 compression kit is compatible with my 97 GC V8, 5.2?

The kit comes with 6 different sizes to thread into the spark plug hole.....8mm, 10mm, 12mm, 14mm, 16mm, 18mm.

The gauge is only $25 bucks and looks pretty easy to use. I figure I should do this first before putting a new cat on and both o2 sensors....upstream and downstream, and new spark plugs and wires.

It has a lot of miles on it.....about 266,200 and I just have no power anymore since the check engine light when on (P0420 low bank 1) and it has gotten worse. I have been suspect of too much back pressure and it has never leaked oil before but now it is, fortunately not too bad.

I don't want to put anymore money into it if the engine is ready for rebuild.

 

[SteelHeadz]

Match up the adapter to the sparkplug thread diameter and pitch and your good to go. Snug the adapter with your finger when you screw it in and that should be sufficient. The adapter should have o-rings on the end of the shoulder to keep it sealed.

 

[cindy8653]

Match up the adapter to the sparkplug thread diameter and pitch and your good to go. Snug the adapter with your finger when you screw it in and that should be sufficient. The adapter should have o-rings on the end of the shoulder to keep it sealed.

Thanks for responding. It does look pretty easy to use and I know there is a dry test and wet test. I know the engine probably won't be 150psi because it is old but what I am looking for is consistency and not much difference between each cylinder....about 10-15psi. I am sure the pistons are wore to some degree given the mileage.

I am just wondering though how many more miles I can get out it. What is the most amount of miles a jeep has on it and should I have high hopes that I can continue to drive it?

 

[SteelHeadz]

Your question has several answers that's similar to a bowl of worms. I'm assuming you bought it used and don't know how the prior owner has kept up with the maintainance. Assuming that he did, how did he drive it?, was he hard on the pedal a lot of times or was he gentle and took good care of whatever it needed to perform like new. I've seen the 5.2 liters with over 300,000 miles and still runs great with some exemptions like burning a little oil and excessive fuel consumption. Those V8's are tough engines but still wears out like any other engines depending on use, and that is what you need to determine by your diagnostics. At that mileage, a loss of a few PSI per cylinder would be normal as long as it doesnt drop below the specified threshold. Valve's wears out too. A cylinder leakdown test would be able to give you some idea on that. Excessive oil gunk buildup in the engine also shortens the life expectancy of an engine due to lack of oil circulation within the engine crank case.

Thanks for responding. It does look pretty easy to use and I know there is a dry test and wet test. I know the engine probably won't be 150psi because it is old but what I am looking for is consistency and not much difference between each cylinder....about 10-15psi. I am sure the pistons are wore to some degree given the mileage.

I am just wondering though how many more miles I can get out it. What is the most amount of miles a jeep has on it and should I have high hopes that I can continue to drive it?

 

[cindy8653]

Your question has several answers that's similar to a bowl of worms. I'm assuming you bought it used and don't know how the prior owner has kept up with the maintainance. Assuming that he did, how did he drive it?, was he hard on the pedal a lot of times or was he gentle and took good care of whatever it needed to perform like new. I've seen the 5.2 liters with over 300,000 miles and still runs great with some exemptions like burning a little oil and excessive fuel consumption. Those V8's are tough engines but still wears out like any other engines depending on use, and that is what you need to determine by your diagnostics. At that mileage, a loss of a few PSI per cylinder would be normal as long as it doesnt drop below the specified threshold. Valve's wears out too. A cylinder leakdown test would be able to give you some idea on that. Excessive oil gunk buildup in the engine also shortens the life expectancy of an engine due to lack of oil circulation within the engine crank case.

Actually my brother gave it to me for free (so the money I've put in to it would be essentially having to pay for it). His wife drove it mostly and they used it frequently to drive to Canada (from Easton Pa) to visit her parents. They have 3 boys but when they had their daughter last spring they gave it to me (they needed something larger).

So the excess miles truly are mostly highway miles. He also had synthetic oil changes so I know that may help an engine last longer. The maintanence factor I think may have been better from them because I have had to revamped the entire cooling system.....new water pump, by-pass hose, new radiator. The charging system is new as well.....new battery, new alternator. New back brakes, completely new exhaust..........muffler, tail pipe, exhaust hangers and clamps and now a new cat, o2 sensors, spark plugs and wires. But he did put quite a bit of money into it through the years.....revamping the fuel system, etc.

I am not going to do a leak down test, just the compression test, but either way I hope I can take it to 300,000 miles. But you are right about the V8 engines lasting longer and I have read other places where people have taken the particular Jeep that I have (1997 Grand Cherokee Orvis) to over 300,000.

That is why I read these forums to get some info on other people's experience with their jeeps.

Thanks for getting back with me. I appreciate it.