5.7 Vortec Roller Lifter Question

I have a 05 235 Bayliner with a Mercruiser 5.7 Vortec engine. Recently the motor started running poorly and a compression checked revealed no compression on cylinders 4,6, and 7. Pulled the valve covers and was able to get it running by adjusting the valves. However, I couldn't adjust the valves what I consider the proper way (remove lash, and tighten extra 3/4 turn). I ended up having to adjust the valves by ear with the motor running. The motor is running fine, but I'm concerned about what caused this problem and future big time damage.

I pulled the intake and verified that it has roller lifters. When adjusting the valves and watching the lifters, it appears the lifters are pumped up all the time and are not compressing. The engine is sludge free but the lifters don't appear to be compressing. Has anyone come across this before and is there a different method to adjusting roller lifters on a 5.7?

Thanks in advance for any and all replies.

 

Not very technical I know ,but I always used a tin of Wynn's engine stop leak at every oil change.

 

How can you tell the lifters are not compressing? They are under the intake manifold so the engine couldn't be running while you look at them.

 

Its possible that if the engine had not run for a long time and badly stored the valve and seat would be rusted not allowing them to seat . Running the engine and making adjustment hammered the rust off them enough to run. Taking out the lash and then 3/4 is not the way. If you take out the lash then that's it I do it running till there is no noise and the idle does not lower.

If you have hydraulic lifters tightening out the lash and then 3/4 would be correct, the lifter would absorb the 3/4 turn. But you say you have roller.

There is no way you can see the lifters working, I don't know what you are calling lifters if you mean rockers,and even then !!!

I would check the compression again --you may need a head job.

There is hydraulic lifters and sold, there is also roller for very violent cams. You cant tell what they are until inlet manifold removed.

Your terminology is confusing.

 

It depends on what year and model marine conversion you have but roller lifters are easy to spot when the intake is removed, they'll have girdles pairing up every cylinder's lifters.

Even if the lifters suddenly leaked all the way down, the engine would have still run. It would have made a bunch of lifter racket and likely stumbled quite a bit, but typically they'd pump up very quickly and the noise goes away. Assuming you have several collapsed lifters (why didn't you pull them out and check, when you had the intake off?) this wouldn't cause you to have completely "dead" cylinders on a compression check. Even with a fully leaked down lifter, you'd still get some pressure build up, not dead zero, because the valve springs close the cylinder, not the lifters.

This suggests to me you had a stuck valve or two. Warm the engine up and set the lash properly, then do a compression test. Why the valves stuck is a guess without seeing the engine, but you're missing something here and it's probably an obvious thing at that. I'll bet you've got some bent valve train elements.

 

Rollers are normally solid. Why would you fit a wild cam and roller lifers that had squishy hydraulics.

 

IF its hydraulic lifters then Forte do a very good additive that will free them...not sure where md is but Forte are South African but of course have a website and are worldwide

 

Would that be big chief running Forte the heap um powerful medicine man. Is that what you would do Piston Buy some magic mechanic and pour it in and fix a broken engine? I guess it does lumbago Rhumatism and all kinds of ailments a whole bottle for 50 cents

Collapsed hydraulic lifters need replacement, there is no such thing as mechanic in a bottle.

 

If the hydraulic lifters are stuck this stuff will shift them ...If you then have it running you can access condition etc and change them if you want ..I thought you were the magic genie in a bottle Frosty !!! ( strange isnt it that Ford were putting Forte additive into the oil on certain models at service and not telling the customer to get around a design problem that was causing warrantee claims ..so that proves its no good )

 

Link to this please. Or its non sence --and dangerous non sence.

 

just Google Forte oils and make your own mind up...No link to the ford problem ..I was making an advert for Forte at a dealership when it came up ..ford admit a problem dont be silly .

 

The rollers on the 5.7 Vortec are hydraulic, as are most of the roller lifter setups currently used in production automobiles. In fact, I don't know of any regular production auto with solid rollers. Solid rollers are used in racing applications where the required frequent adjustment will be addressed regularly.

Again, all this talk about stuck or collapsed lifters is silly, as they can't cause the symptoms he's describing. The lose of compression in multiple cylinders can only be caused by hung up valves. Be this because of broken springs, retainers, cups or seriously screwed up guides. I suppose you could have cracks all over the head, but there would be other symptoms showing up.

Even a collapsed lifter will move the valve, assuming nothing else is screwed up, so . . . zip compression in several cylinders means you need to tear into this engine some more. You can try super goo in a can, but you'll probably just be putting off the inevitable, which is yanking the heads for a good look see. While you're there check the lifters this time, and the push rods and the valve springs and the retainers, etc., etc., etc. I'll bet you bent up some valves and they're binding up in the guides.

 

I wouldn't normally subscibe to the "gunk in a can solution ", but many years ago I learned the Stop Leak trick when servicing Rover v8's {BOP215's to some of you} These engines could be completely sludge free and yet still suffer from sticky lifters, especially if not used for a while , I always add it to an oil change ,in any engine with hydraulic lifters.

 

The early Rang rovers had bad cams and followers as the Brits call then. The 3.5 P6 body did the same. It was a warranty replacement in 1968.

The followers had hollow bottoms --yes crap and were all replaced. Some were so bad they came in misfiring. This engine had no cam retainer but were held in place by a 1 degree angle to the cam head. crap stuff no longer made.

Cortina MarK 3 over head cam 2000 cc same a disastrous peice of crap.

Stop leak by wynns did work but so does an egg.

There is nothing in a can fixes engines.

 

Frosty, you are muddlng your stop leaks up ,this one is an oil additive ,not a radiator/water pump leak cure like an egg