tewks

So I bolted on my refreshed heads and started putting the rockers/push rods back in. These are the mark V heads with bolt down rockers, nothing adjustable. When I tighten down the rocker, instead of the lifter compressing a tad, the valve comes off its seat! This can't be right... So I pull out the lifter for a look and sure enough, its frozen, won't push in at all. Then I start checking the others, they're all like that!! Next step, I take one of them apart, look it over, nothing obviously wrong, put it back together, it depresses just fine. WTF? Is there some trick to reinstalling these lifters? Assuming they need to be replaced, what's a good source? (Merc want $66/per...not!) Thanks!

tewks

Thanks, I hope it's that simple. I had tried to compress one of these by hand before disassembling it, probably put a 100lbs on it and it wasn't budging, and I did crank the engine with the lifters installed, and again, no effect, the valves were still off the seats. I guess worse case, I have to take them all apart (and hope I get them back together again).

Griff

Do you mean the rocker arm slides off the top of the valve?????

Did you reinstall the pushrod guideplates????????? If they are on, I don't see how this could happen.

Did you take out all the lifters and if so, did you put them all back the same bores that they came out of??? If not, I would get new lifters. You can get a set of Crane lifters for less than a $100.

US1 Fountain

iTrader: (1)

I've heard of new lifters that are sticking. Not unheard off, but all of them?

RedDog382

Were the heads shaved?

tewks

When I say the valve comes off its seat, I mean the lifter doesn't compress at all, so when the rocker's are tightened down, the effect is that the valve opens.
No the heads weren't shaved. The seats were taken down about .010. The lash in the pushrod goes to zero when there's about 1 full turn left on the rocker bolts, which indicates the geometry is what it should be.
These lifters are just stuck! For $100 bucks it would be worth the peace of mind. Where's a good place to order them? Is in generally easy to cross a mercruiser part number? Looking though the merc parts catalog, there's a different part # for the lifter on virtually every gen vi engine. I have the oddball 96-97 engine with the l29 block and mark v heads, I don't even know if they put those in cars/trucks.

Griff

Are you tightening all of the rockers at once without rotating the engine????
There is nothing wrong with doing it this way with non-adj rockers
If you are, it will force some of the valves open depending on cam lobe positions.

I say tighten them all and then crank the engine over. There is no way there is something wrong with all 16 lifters.

hillbilly24

im with griff crank em down and crank it for a while and im willing to bet everything will look cool afterwards, this isnt uncommon at all for that valve train, If it were me I would put the rest of it together and fire it up but if I tell you to do that without cranking it and checking it and im wrong then i will be the worlds biggest A hole so check it out first but im sure there is nothing wrong

Mbam

Just leave it sit, they should bleed down all by themselves. I doubt if any of them are off the seat far enough to tag a piston.