valve lash and compression.

[86rangerxlt]

does anyone know what the valve lash specs are. i seem to be having problems with no. 5 cylinder not holding compression.. also when doing a compression test on the 2.9 what are the ideal numbers. thanks in advance.

 

[Original_Ranger84]

If I'm not mistaken the only v6 motor to use non hydrolic valves was the 2.8L, all other v6 motors have the non adjust valves.

 

[86rangerxlt]

i thought that too even the book states this. but im having valve problems. currently the middle cylinder on the drivers side is losing compression very quickly. i believe this may be my cause for oil pressure loss. i have spark. but whats bothering me is on the same cylinder on the passenger side i can unplug the sparkplug wire and the motor doesnt change. but yet i have spark and compression on that cylinder. so im thinking it has to do with either the piston rings, or the valves. in the morning im going to back off that valve and see if im still losing compression. if i still am id say its most likely the rings. originally i didnt adjust the valves when i replaced the head gasket and put my resurfaced heads on. but i ran into problems. valves were ticking like crazy. so i tightened them down then fixed the timing. truck ran great then came the problem of the dropping oil pressure. took it to a shop and he recommended a new motor cause i had a "dead" cylinder. but all he did was unplug that one cylinder and see no change.

 

[Mike828]

Have you checked the fuel injector for #5?

 

[86rangerxlt]

no i have not. ill check that out.

 

[Original_Ranger84]

So you were actually able to adjust the valves? Also I usually say between 150 - 170 seems to be the best for compression I think?

If you are sure your losing pressure and not just a lack of power from it not firing then I would say its a ring problem, a valve should close when under compression unless the cam is holding it open for exhaust or intake. Or a Head gasket blew. I would check your oil for a gassy smell and your coolent to see if its low.

 

[86rangerxlt]

yes i was able to adjust the valves. im pretty sure its a ring problem cause i had blown a head gasket and had cylinders filled with coolant. pretty sure that destroyed the rings. since i didnt tear it down right away. i am getting a lack of power when i drive along with oil pressure loss. but ive done a compression test and it gets to 90 then drops pretty quick. but its only on that one cylinder. i figure if its not that its a valve staying open causing me to lose compression. im sure my oil will smell gassy regardless cause i did an engine flush like a week ago with diesel fuel.

 

[Original_Ranger84]

Well the only other way I could say that it is the rings is to check your plug and injector for crud build up.

 

[86rangerxlt]

i rechecked the compression again today. this time pulling all the wires and plugs instead of just the one i was testing. tested each one 3 times. came up at 150 on all of them and no drop in pressure. pretty much told me that the mechanic is full of baloney.

 

[n_grimm]

If you decide to adjust the valves, I hope you don't do what I did. I tried loosening the adjusters to 0 lash while it was idling and broke one of the bolt heads off. Also want to mention that I had a miss caused by a nearly plugged injector. One symptom was I could hear it knock/ping slightly due to lean detonation just revving it from idle. Wouldn't want to run it too long that way or it would burn a piston. Not really that hard to check.

 

[Original_Ranger84]

i rechecked the compression again today. this time pulling all the wires and plugs instead of just the one i was testing. tested each one 3 times. came up at 150 on all of them and no drop in pressure. pretty much told me that the mechanic is full of baloney.

Sounds like a bad injector or fouled plug then. Easy Fix!

 

[86rangerxlt]

well then i think im gonna check my spark plugs. or better yet im just going to get new ones. its about that time anyways. and ill check my injectors.