could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

[chris0061]

I over revved my engine a couple seconds and when I backed off I heard a light knocking back there. I tried to find it with a stethoscope to no luck. you couldn't hardly hear it till about 15 hundred rpm. I took the valve covers off and tried to locate it then thought I seen a couple bent push rods so I replaced them. then it was still there so I thought I'd try adjusting the rockers. I got to number 8 intake and I backed it off like your supposed to then tightened till the tapping quit then started my 1/4 turn more and no sooner than I got started turning the knocking came I backed it off it quit. I took the push rod out and you could tell the end was being beat up as it was not perfectly round like the end on the rocker. What ya think?

 

[Bondo]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?
What ya think?

Ayuh,... I think you're Lucky that's All that's Broken...

 

[IVAZ]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

With the push rods being bent it sure would seem a lifter was trashed. Maybe a valve was also damaged. Is there any knocking coming from the bottom?
I wasted a 454s bottom end doing the same thing. It was weird, but all my push rods, lifters and valves were fine.

 

[MikDee]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

While you're at it, Check to make sure you didn't break any valve springs, one way to tell is if you can turn them easily with no pressure on them (with rocker arms loose).

 

[180shabah]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

I think you're Lucky that's All that's Broken

Very lucky...

 

[chris0061]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

I put the scope to the pan and didn't hear anything out of the ordinary. I could'nt even locate the knock anywhere with the scope but could hear it when you rev ed the engine. I"m going to take the intake off Friday and look. oil pressure is good temp is good, no missing or backfiring. I'll check the valves also as if I see a bad lifter I may as well replace all of them right? and the push rods?

 

[IVAZ]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

I put the scope to the pan and didn't hear anything out of the ordinary. I could'nt even locate the knock anywhere with the scope but could hear it when you rev ed the engine. I"m going to take the intake off Friday and look. oil pressure is good temp is good, no missing or backfiring. I'll check the valves also as if I see a bad lifter I may as well replace all of them right? and the push rods?

Yeah I would replace all of them. If one actually broke, the others took a good beating and might not be far behind. Remember to get oil in the new liters before installing.

 

[FreeBeeTony]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

Just curious.........how did this "over_reving" occur?

 

[MikDee]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

I would examine all the pushrods, and replace them if necessary, but only replace the faulty lifter, the others are still doing their job.
The suspect cylinder might have spun a rod bearing, then you have your work, & that cost, to deal with, why spend it on lifters.

The scary part is, when you adjusted cyl #8, it seems that once those valves were adjusted, & firing propperly, the knock began again,,, meaning once there was combustion pressure on it, this could be an indication of a spun rod bearing. Then again, it could be just the pushrod, or lifter.

 

[J. Mark]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

remember to prelube the cam with assembly lube if you replace lifter/lifters and follow normal break in procedure of running the engine at 2000-2500 RPM for 20 minutes-DO NOT DO THIS ON THE MUFFS! Put the boat in the water.

Your hose can't provide enough water to run at that RPM.

 

[IVAZ]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

I would examine all the pushrods, and replace them if necessary, but only replace the faulty lifter, the others are still doing their job.

Seriously, you would rather take the intake off again when another lifter crapped out? They were never designed for 6000 RPM and they are already used. Even under normal conditions they will wear out. All the pushrods and lifters can be had for about sixty bucks.
He already said there was no bottom end noise.

 

[Polar_Bus]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

I put the scope to the pan and didn't hear anything out of the ordinary. I could'nt even locate the knock anywhere with the scope but could hear it when you rev ed the engine. I"m going to take the intake off Friday and look. oil pressure is good temp is good, no missing or backfiring. I'll check the valves also as if I see a bad lifter I may as well replace all of them right? and the push rods?

Also make sure you didn't start to pull a rocker stud(s) out. They are only pressed in from the factory (unless the marine engines have the studs roll pinned, but I doubt it).

Lay a straight edge rule across all the rocker studs, if one is higher then the others you have a stud pulling out

 

[MikDee]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

Seriously, you would rather take the intake off again when another lifter crapped out? They were never designed for 6000 RPM and they are already used. Even under normal conditions they will wear out. All the pushrods and lifters can be had for about sixty bucks.
He already said there was no bottom end noise.

Nonsense! I've had many Chevy V8's up to, & past 6k over the years, and never had a problem with their hydraulic lifters! and I'm talking about even as far back as my 1962- 327/300hp Impala SS that would easily rev to 7k. I used to take it to redline on a regular basis, But, always on a wind out in gear, Never free running (I avoid that like the plague) that's what kills them! but, come on, once, or twice, accidently overreving, they're better then that I don't see a reason to replace them all but that's my opinion.

 

[IVAZ]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

Nonsense! I've had many Chevy V8's up to, & past 6k over the years, and never had a problem with their hydraulic lifters! and I'm talking about even as far back as my 1962- 327/300hp Impala SS that would easily rev to 7k. I used to take it to redline on a regular basis, But, always on a wind out in gear, Never free running (I avoid that like the plague) that's what kills them! but, come on, once, or twice, accidently overreving, they're better then that I don't see a reason to replace them all but that's my opinion.

MikDee,
I will respectfully disagree with you. If one push rod was bent, to me that means the rest took a fair amount of stress also. I would hate to pop the intake off again for lifter issues. The money required to replace them is a small amount.
My father drag races as a hobby and the only lifters he uses are solid. They hold up much better than hydraulic. The high RPMs kill hydraulic lifters. I?m not suggesting he use these as I believe the extra amount of time they hold the valves open might be negligible on a marine engine. Im just saying stock 350s lifters dont like high RPMs.

 

[MikDee]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

MikDee,
I will respectfully disagree with you. If one push rod was bent, to me that means the rest took a fair amount of stress also. I would hate to pop the intake off again for lifter issues. The money required to replace them is a small amount.
My father drag races as a hobby and the only lifters he uses are solid. They hold up much better than hydraulic. The high RPMs kill hydraulic lifters. I?m not suggesting he use these as I believe the extra amount of time they hold the valves open might be negligible on a marine engine. Im just saying stock 350s lifters dont like high RPMs.

In an all out racing engine solid lifters are the way to go. I've had my share of them too, trying to adjust a running engine with a feeler gauge is fun but, can be done and have had the rocker studs slowly pull out after awhile, until you pin them, or get threaded ones.

And where do you think the 350 lifter design originated from? the 265, 283, and 327, and hi-perf 327, these lifters are pretty sturdy. I've floated Ford lifters easy yrs ago, they were known for that, but never a Chevy.

Car engines normally are normally pushed to 5500-6000 all the time in street racing with hydraulics with no Ill affects!

And boat engines are usually built stronger

 

[chris0061]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

OK good feedback. I over revved it cause I put a different upper on and it said v8 on it so I assumed it was the same gear ratio. Anyway I was just kind of cruising on the choppy water then hit calm water so I wanted to push it a little and that's how I over revved. When I take the intake off I'll do the straight edge on the studs and see whats going on in there. I'll let you all know. I may even tear it down tonight. Thanks all

 

[Polar_Bus]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

In an all out racing engine solid lifters are the way to go. I've had my share of them too, trying to adjust a running engine with a feeler gauge is fun but, can be done and have had the rocker studs slowly pull out after awhile, until you pin them, or get threaded ones.

And where do you think the 350 lifter design originated from? the 265, 283, and 327, and hi-perf 327, these lifters are pretty sturdy. I've floated Ford lifters easy yrs ago, they were known for that, but never a Chevy.

Car engines normally are normally pushed to 5500-6000 all the time in street racing with hydraulics with no Ill affects!

And boat engines are usually built stronger

You may get away with revving a stock SBC to 6 grand a few times, but a stock valvetrain WON"T put up with those rpm's for long, peticularly the stock pi$$ weak valve springs will cause valve float, or a broken spring. Can't tell you how many guys running relatively stock valvetrain SBC, left the dragway with a broken valve spring(s)

 

[MikDee]

Re: could over reving 81 mercruiser 260 to 6000 cause lifter to colaps?

You may get away with revving a stock SBC to 6 grand a few times, but a stock valvetrain WON"T put up with those rpm's for long, peticularly the stock pi$$ weak valve springs will cause valve float, or a broken spring. Can't tell you how many guys running relatively stock valvetrain SBC, left the dragway with a broken valve spring(s)

I've done it quite a few times, with a bunch of Chevy engines in the past going through the gears, and never had a problem? But mine were only used on the street. Maybe I'm just lucky

I had a 63' Plymouth 426 Ramcharger with a solid lifter cam that used to shoot out pushrods on occasion when you got on it

And my friend with his Fords, used to float his lifters all the time, he used to have to idle it down, & wait for the oil to go back in the lifters, and his engine to smooth out, before he could drive it.

I once bought a 75 Chevy Monza Spyder with a 262V8 & 4spd, 60k city driven miles on it, that ended up needing a cam (it was flat!) I put a 327/350 cam, & lifters, in it, and it would wind out to 7k (the Max) on the tach going through the gears, with a 2bbl! I had no problem with that either, but it was no longer an economy car