What causes a lifter tie bar to break
 

Just like it says
Trying to figure out what happened.

Found it
Intake body broke allowing bearings, wheel and axle out. Body grabbed cam spun and broke tie bar.
Tie bar hit oil splash shield snapped pin holding bar on exhaust lifter and that spun too....grrrrr

Weak valve springs. When the springs get weak, the lifter flys off the lobe, stressing the tie bar rivet until it eventually fails and lifter spins, roller skids on cam until roller gets loose....etc. Been there and learned the importance of checking valve spring pressures as parts of the maintenance program.

Why in the world would you routinely check the most stressed part of the engine? Isn't it more important to wax and polish the valve covers rather than check what's going on underneath them?

Wouldn't expect a mild 80 hr+/-engine that's never seen 5k rpm to need valve springs. 😏

If it failed that soon, there's a good chance the springs were never up to the task from the start. There's a wealth of info here. Contact RM Builder (Bob Marada, Marine Kinetics) when it's time to buy the components. Bob will set you up with all matched valve train components so you don't have to go through this again. And his prices can't be beat.

I did some back tracking, you have stock 502MPI's ? I found a thread you where asking about upgrading 502MPI's to 540's ? Best of my knowledge, stock 502MPI's came with flat tappets at first, and then OEM GM dogbone roller lifters that don't use the tie bars.

So, what do you have ?
If aftermarket stuff, what spring pressures ? What cam ? What other valvetrain pieces ?

beat me too it,,what lifters do you have?will help us figure it out.

First off they are 540" with Dart Iron Eagle 305 heads and 502 mpi intakes with reflashed ecms.
I did not build them so I do not have all the info on the builds.
The lifters are PBM, cam specs unknown until I pull timing cover, I need to get back with a spring tester to check pressure, but they are double springs with damper (Orange stripe on outer spring)
Crane 1.7 roller rockers with guide plates

My plan is to call Bob M to discuss valve train. IMO 80 hrs is unacceptable for valve train failure on such mild builds, not like they are 1200hp solid lifter beasts.

lifters sound chinese and cam could have come from SB and my friend.:D

LOL. Could be....maybe one of his roller buttons (he and his ex wife made in the garage) broke, the cam moved far, and a lobe caught a lifter.

So I did some research, looks like valve spring is a comp 954
210 seat/530 open, it's the spring that comes with the assembled 308 iron eagle.

Well valve float sure wasn't the cause

Lol ya think?
Maybe too much spring?!??
Going to try to get down tonight and pull timing cover off to get a look at cam #s

what lift cam ? possibly coil bind without enough installed height ?, need to match the springs, retainers to what the cam needs..

[QUOTE=ezstriper;4362423]what lift cam ? possibly coil bind without enough installed height ?, need to match the springs, retainers to what the cam needs..[/QUOTE
Need to get the timing cover off to check cam #s hope to have time today
I did not build theses motors

Dart iron eagles came with either the 954 comp, 936 comp, or the vasco H-11 springs.

936 145lbs seat max lift .660
954 195lbs seat max lift .690
Vasco 250lbs seat max lift .790

Over springing a hydraulic lifter that is incapable of sustaining higher spring pressures, can also have negative effects on valvetrain control, just like under springing. Like if trying to run 500 plus lbs of pressure on a autozone flat tappet with 5w20 oil lol

On any performance motor , I would never put on an assembled cylinder head from a head manufacture without disassembling and checking everything.. Spring pressures are usually off , installed height is off and valve job is wrong for the application.. U have to realize they don't have engine builders or machinists assembling them ..

Dart lists it at 190 @ 1.900
Comp lists it at 210 @ 1.900
who to believe?

Understood and have done on my own builds in the past, they may have checked them out I don't know.

Comp, but, really...You, when you measure it yourself.

Just bought a brand new spring tester, not going to rely on old one, should be here tomorrow

On another note Cams are just 791's 2* advanced, but looking up Cranes recommended dual spring it shows I'm a little short on the open pressure.
Crane recommended spring is 150# on the seat and 560 open, I've got 210 and 523 per Comp.......... could be my problem
What I find really interesting is how light a spring the recommended beehive spring is, might be a nice upgrade since its apart

Are talking about this cam?? I'm seeing 498lbs open. If thats the cam, and you have springs calling for .690 max lift, you may have been playing with fire, as while theoretically, you will have .680 lift with a 1.7 rocker with that cam, but, do you really? or is it more? Was it checked?

http://www.cranecams.com/product/car...detail&p=24234

No this one 168791
http://www.cranecams.com/product/car...detail&p=24287


This is spring
http://www.cranecams.com/product/car...detail&p=26253

Sure, that spring is rated at 560 open, but at 1.150. With that cam, you will not see that open pressure. The cam card itself, recommends a 150/405 open (at max valve lift).

That is a small cam for a 540 btw! and its advanced? :helmet:

So do you think that the existing springs will suffice? That it just a bad lifter or lifters? I looked them up and they are supposedly made by morel.

Yes I know it's small, but they have 502 mpi intakes (with cut down dividers and maybe extrude honing, the runners are very very smooth) how much air are they going to flow?

Yes there was a Cloyes Hexadjust gear 2* advanced

Feeling the need to forget about trying to figure out what happened and start from scratch, cams, lifters, rebuild heads with matched components, ditch the 502 intakes

Pretty hard to say what in fact really happened here. If you truly have the "morel" PBM race style lifters, and the body cracked, I'd like to think something is wrong, seriously wrong to have caused that. That is a stout lifter. But, like anything, chit happens. Bad geometry, spring setup, lifter collapsing, incorrect lifter bore clearance, simply a part failure, etc.

I guess it depends on what your goals are. You certainly have the cubic inch, and cylinder heads, for an easy 600-650HP + build. I do think you are camshaft and induction limited currently.

w/o degreeing the cam,the 2° advance show on the gear could just be getting the cam straight up.

They say PBM on the tie bar, maybe not race lifter

It's a heavy boat, top speed is not my main concern. Based on 60 hrs of running this season, the boato just likes 40 mph cruise, hull gets up on top and smooths out. This took 3800-4000 rpm to do with 28 p B 3, topped out at 51 @ 4950. If I could make more (reliable) power to get cruise rpm down I would be happy and hey if it picks up a few on top I won't argue.

I reread the thread and did not see listed that u are running the taller lifters.. off your cam card.

Remarks:
CRANE 16535-16 LONG TRAVEL HYDRAULIC ROLLER LIFTERS MUST BE USED WITH GREATER THAN .570 LIFT CAMSHAFTS TO PREVENT ALIGNMENT BAR

at this point I would contact Bob M. and talk it over with him...

I was assuming these engines were in a 30 sonic. Being a 45 excalibur, my guess is you wont be running 6000rpm across the water. In that case, your cam, and mpi intake , might be a good choice for what you have there

or do what it says on the cam card.

I am going to respectfully disagree with this statement. In the couple of dealings that I have had with Bob, although he is seemingly very knowledgeable, his parts that he is peddling are less than desirable. I am talking specifically about junk Morel liters that you cannot preload and camshafts that are ground incorrectly possibly due to the hand written cards. And by the time that you pay shipping on every part that is dropped shipped from somewhere else, you will have about twice the money in it as you should. Sorry, Bob. Not a hater, we just can't do business any more.

Junk morel lifters? Care to explain?

Jamie I'm not going to broad stroke here and say they are junk I'm sure there are many that are working fine.
Not sure I'll ever know why, but I do have the remains of a PBM lifter scattered throughout one of my engines.
Saw a comment on a web site that said around 60 hrs they had problems with the .842 lifters, maybe Internet talk? But at around 80 I've got a mess to clean up.
According to what I've been able to dig up Callies makes Morel, PBM, Cam Motion, Lunati and others, same lifter just different brand names.

I personally don't have enough confidence to put them back in after refresh and will be taking them out of other motor too.

I hear ya, I'd question those as well. I was going off of snapmorgans comment. I've had crane, lunati and a few others all come apart. I have about 10 sets of morels out there I setup and installed with no issue yet, hoping not for 300+ hours. How was your valve train geometry? What pushrods were used?

Ive had good luck with my 4603 morels so far. A buddy of mine, had tie bar failure on his . A couple other setups friends of mine built had issues with them collapsing.

Im going to be tearing into mine soon and see how things are looking.

I believe morel makes the lifters for pbm, howards, lunati, cam motion, possibly crower ?

I did have an issue with a collapsed lifter early on, not sure if it was due to the lifter, or something else. Only one lifter was bad. So i was able to order 1 pair of lifters from lunati. They are the same as the 4603 morel, i wanna say the part number was 72431 ...id have to check my lunati catalog when i get home.

Nothing to do with geometry. Bad from the get go. To be more specific, I have had 2 sets of hydraulic roller lifters that about half of them would not adjust. The plunger would not depress. They acted like solids. Both sets were replaced, but had 2 collapse on a very mild setup. .625 lift 150/450# deal after very low hours. Not interested in ever using them again. The stock GM ones have worked perfectly in both of these aps where the Morel's didn't. I am not sure of the exact part# of the ones I tried, but they were sent with the cams from Bob. Oh yeah, and the cam that was ground wrong cost me an engine from reversion in about 2 hrs run time. Has since been corrected and running strong, but not with those parts.

The roller tips are right in the middle of the valve stem, the rocker was still tight in the lifter that came apart. I don't know the brand of push rods and haven't measured them but they are pretty stout looking and tapered. Looks like Crane pushrods,guide plates and gold rockers
You'll have to forgive some of my bbc ignorance. I've been playing with 440's and Hemis for a long time! I'm trying to learn as much as I can about BBC as quickly as I can....I've come over to the dark side LOL

From what I've bern able to find Callies makes Morel and many others same products different brand names....kinda like Air conditioning 7 mfg 88 brands