: lifters (how do you no if it bad)
04-26-10, 09:10 PM
the question i have is how do you no if your lifters are bad ? seems like the amount of spring movement on some of my lifters are differnt than others and a few had no spring movement at all untill i kept pushing and messing with them till they began losening up. is there specs. on the amount the springs are allowed to compress ?
We need more info - what year engine - what are you doing - what do you mean by spring movement?
04-27-10, 03:09 AM
engine =1999 4.6L- 575 h/p @ low boost of 8 lbs, twin turbos, built by redline performance in 2005, approx miles = 10,000 at the most. it is in a sand rail
valve train noise. the tic, tic noise
spring movement I am talking about is on the inside of the lifter, the part that makes contact with the valve stem. I am assuming they are supposed to have some kinda of spring action which works like a pump for oiling purposes, if not I have got a lot of broken lifters ?
04-27-10, 11:26 AM
In a 99 the cam follower (lifter) is a cupped hydraulic unit which sits over the valve tip and spring retainer. Each cam lobe acts directly on the follower, similar to a flat-tappet hydraulic setup. Pressurized engine oil for the hydraulic function is supplied through passages surrounding each follower: the system operates as a zero-lash valvetrain, so there should be NO "tick-tick-tick-tick".
Two things - either the case hardening on the cam and/or follower has worn through and the cam has eaten a dish into the follower face (not uncommon and requires cam and all follower replacement) or the valves themselves are sticking in the guides, holding them open to some degree. Take a hard look at each pair of cam lobes for a particular cylinder: is each lobe identical in the height of lift and the lobe nose shape ?? If the cam lobes are worn/galled/chipped - hang onto your credit card.
You say that you banged and messed with the valves and a few started to operate again (to some degree). This would be stuck valve(s) and that's not common in a Northstar. It might be an artifact of the turbo setup, but I doubt it.
In any event, stuck valves or worn followers is NOT GOOD and requires mechanical work to fix. Lots of it. They will not unstick with magic oil potions or such - it takes work.
Are the lifters in the engine, or in your hand on a work bench? If they are out of the engine you can compress a lifter fairly easily, especially after you pump som oil out of it the first time you push down on it. In the engine its pretty much impossible to push down on a good lifter unless the groove in the outer diameter of the lifter is aligned with the oiling port in the block.
04-27-10, 02:47 PM
first off, thank you to everyone for your input, it has been helpfull.
mark c, yes i have the lifter in my hand. i can compress them by squeezing them with my hand. that is what my question is, how much should they compress ? it seems to me that my lifters are not compressing the same when i squeez them by hand. i have pumped the oil out of them by squeezing them, i then soaked them in some wd-40 and pumped them by hand while they were submerged in the wd-40 but they are not all the same, some i can squeez say 1/16'' some 1/8'' some 3/16'' and i have worked them by hand quite a bit thinking i could work them loose so they would all compress the same amount, but have not had any luck. i went and bought 1 lifter from autozone to see how much movement i could squeez on it and it didnt move at all, so i soaked it in the wd-40 still not able to squeez(solid as a rock)so i get the air hose with 90lbs presure and blow in the port on the outer part of the lifter (where the groove is)and oil starts comming out of the inside of the lifter, still cant compress it, so i try and tap on it with a small hammer and punch and it now moves about 1/32'' so now i am really not sure as to how much they should compress ? time to buy a manuel
04-27-10, 03:06 PM
An empty follower (lifter) will compress easily. If it/they are filled with oil as is normal during running, you can't compress oil - it's hydraulics !
Your first post didn't say the followers were out of the engine - that's a whole different set of conditions; in the engine the followers are always as hard as a rock and DO NOT COMPRESS - ever. The engine lubrication system supplies full oil pressure to the follower galleries, the followers do bleed a tad of oil, but they are always full of oil (and must be pumped full again before you install them: submerge them in oil and pump the plunger until all air is expelled) and, if one has a chip or dirt in it it will "collapse" and that's the rap you hear in some cars for 8 - 10 revolutions at cold start.
I believe the reason that you can't compress all the follower plungers equally is that there is more or less oil left in each follower, so you get different plunger travel. Take one apart and look at the guts - there's more in there than you think. The center plunger should come out with removal of a snap ring or circlip.
The face of each follower - the cam lobe contact face - should be mirror bright with no dishes or galling, no pits. No circular scoring: the followers are offset by a few thousandths in relation to the cam lobe so they rotate in their bores.
04-27-10, 06:14 PM
Thank you submariner409 ! great info, makes a lot more sense to me now. maybe you could give me your thoughts on the low compression reading on the #1 cylinder. i will post the question under the correct topic.
04-27-10, 06:24 PM
Post your compression work in here - it's all concerned with engines and valves - This is the Northstar performance forum.
One cylinder with low compression - all spark plugs out, throttle blocked wide open. Pull the IGN fuse. Roll the engine 5 times for each reading. Lets' say most of the cylinders read about 150 psi. You want, ideally, all 8 cylinders within 5 psi of each other, but if they're all within 10 psi of the average you're OK. BUT, let's say the average of the best 6 or 7 is 150 psi and one reads 100: not good.
Inject a teaspoon of oil into the low cylinder and roll the engine a few revolutions - now do a compression check. Pressure come up to close to the 150 (?) average or so ??? Piston rings. Pressure come up hardly at all ?? Valve or head gasket problems.