Have problem w/ my rebuild.

[FreeBeeTony]

Went fishing this morning.......ran 15mi offshore w/o any issues, ran great 30MPH at 3600RPM.
On the way in everything seemed fine.........then it felt like someone grabbed the boat and slowed it down.
Thought I might have ran over a piece of rope or something........shut it down immediately and lifted the OD to look at the prop.........didn't see anything.,,,,,

.I started it up and it made a lot of noise​

​

Proceeded to call the coast guard ant towing service as I thought I was dead in the water.........Then I realized I started it w/ the OD tilted all the way up! Lowered the OD, started again and it seemed better.......not perfect, slowly got up to 20MPH and returned to my dock......before doing so was able to get to ~3000RPM....anything more than that it bogged down.
Here are thing I'm going to check:
1) pull each plug wire to check for contribution
2) put a vacuum gauge on and check
3 check to see if I dropped a exhaust flapper
Have a funny feeling I may be a broken rocker arm or pulled out stud......if this is the case it should show up in #1 and #2.
If these test are inconclusive.......I'll be doing a compression test.

 

[FreeBeeTony]

May have found something........see video.
Went down to the boat and performed tests #1 & #2 from post #1.
Looked up the readings online.......don't see anything conclusive.
Plan on pulling the starboard valve cover and see what I find.

Any opinions are the vacuum gauge readings?

https://www.youtube.com/watch?v=y4RjoZqbVVE&feature=youtu.be

 

[FreeBeeTony]

Bump
Bondo
AllDodge
achris

 

[alldodge]

Low vacuum and bouncing like that would be valves not adjusted correctly, valves are staying open. In a worn out motor most would call it valve guides sticking

 

[kenny nunez]

Is your cam a roller or flat tappet? From the video it looks like an intake valve not opening. If it was an exhaust valve there would popping back through the carburetor.
If you have a flat tappet cam did you use cam break in lube and a zink additive in the oil? If not the cam may have a worn lobe.
Hopefully it is just a pulled stud, broken exhaust valve spring or broken rocker arm.
Good luck.

 

[Lou C]

I wonder if it could be as simple as the rocker adjusting nut backed off on one or more cyls?

 

[FreeBeeTony]

From the video it looks like an intake valve not opening.
.

Kenny hit the nail on the head!

Took the starboard valve cover off and found the intake rocker laying next to the valve.......the stud sheared off.
Question: can I pull the broken stud out of the head and install a new one and pin it w/o removing the head?

 

[Bondo]

the stud sheared off.
Question: can I pull the broken stud out of the head and install a new one and pin it w/o removing the head?

Ayuh,.... I donno, but it seems there'd be abunch of ground up cast iron floatin' all over the place,.....

No doubt cleaner, 'n easier on the bench,.....

 

[kenny nunez]

It is worth a shot to try removing the stud with the head still on. Pinning the new stud is a good idea. Getting the old one out is the problem. How much of the old stud is sticking out? If there is any at all you need to really stay on center to drill it and tap it to 1/4” 28 at least 1/2” deep. With a 1/4” 28 stud and spacers to draw it out. If you could heat the area that should help also. A high quality drill 13/64” is the drill size for 1/4”28 using a starting tap then a bottoming tap with drill and tap oil. Do not break the drill or tap in the hole.
If there is at least 1/2” sticking out try to run a 3/8 “ 24 die nut over it enough to get a nut on the stud with some washers to draw it out.
A shop vacuum comes in handy for this also. Good luck

 

[FreeBeeTony]

There is about 1/2" of thread still on the stud sticking out.........only 1/4" sheared off.
Going to try and remove it early in the morning.....maybe try some heat.
Got a replacement "press-in" stud.......gonna put in the freezer overnight until I get the stud out.....pack it in ice and bring it to the boat to try and install w/ a dead-blow hammer. Will also try to drill/tap a hole for a set screw.

Sound like a plan?

 

[kenny nunez]

A set screw at a angle should do the job. Something like a 10/32 set screw is what I used once. Hopefully that will be the only one that was weak.

 

[alldodge]

There have been so many different threads for you rebuild its hard for me to keep up, but were the nuts over torqued at first and then redone?

 

[FreeBeeTony]

The rockers (roller) were adjusted properly.
As far as my posts/threads are concerned......if I was to keep adding on to the one thread, a subject such as this would not get noticed............IMO.

Going to the boat now to try to remove the remainder of the stud.

 

[alldodge]

No offence meant I just said "I" could not keep up, this is why I asked the question. Sorry for my comment, I'm out

 

[GA_Boater]

There have been so many different threads for you rebuild its hard for me to keep up, but were the nuts over torqued at first and then redone?

So true and mentioned before, but ignored.

if I was to keep adding on to the one thread, a subject such as this would not get noticed

Just like all the active threads we have that stretch back 8 or 9 years in some cases. /s

 

[Lou C]

You know I do recall something being not exactly right with the heads when you first got them back...valve stem height or something like that, right Tony?

 

[FreeBeeTony]

Yes, the valves weren't installed properly, they were fixed.........did not have anything to do w/ the p[problem
I removed the broken stud and installed a new one. Had the new one in hthe freezer overnight..........seemed to help during installation;

Here are a few pics:

 

[kenny nunez]

You lucked out getting the stud out. Sometimes things go right after all. Good job.

 

[Lou C]

Great work & follow up.

 

[FreeBeeTony]

Another Broken Rocker Arm Stud

Went out fishing this morning.........cruising @ 3600RPM's, out of no where the engine speed changed.
Long story short.........found another broken rocker arm stud; this time on #3 intake, last time #2 intake.
WTF..........I heard of the Vortec studs pulling out but not breaking.........

Anyone else hear of this problem?