Hi Guys,

Its been a long time, but my engine/boat problems aren't over

My previous thread where I replaced the engine is here:

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=51037&PN=3&title=1989-sn-water-in-oil-wet-plug" rel="nofollow - https://www.correctcraftfan.com/forum/forum_posts.asp?TID=51037&PN=3&title=1989-sn-water-in-oil-wet-plug

Since fitting the "new/used" engine and getting it running last year, I only used the boat for 3 days and everything was great.

Then a week later (still in December 2023) the boat was running great, but then while cruising for about 10 minutes at ~2500 rpm I heard a knocking sound.

It was a deep knocking sound, at a rate of about 2 knocks per second. I slowed the boat down, and it idled fine, and the knock slowed down to about 1 knock per second. I sounded like it was coming from the back of the engine (transmission side) but it is hard to be sure as the cover was closed.

I shut the boat down, but couldn't see anything wrong. I tried to restart, but it puffed and spluttered and would not start. So I towed the boat in. I am not sure if the starting problem is directly related or maybe it was totally heat soaked?

I have been so busy this year that I haven't had much time to diagnose.

- Plugs look fine

- Oil looks good - no metal shavings

I have pulled all the plugs, disconnect ignition and raw water pump, and cranked the engine. It turns over smoothly, no noises.

I then did a compression test, and all cylinders were around 140 psi, but what was strange is than during the compression test of cylinder 4, it made a puffing sound (almost like a backfire) at the intake area. None of the other cylinders did that.

Any suggestions or ideas?

As a starting point, maybe pull the valve cover off and look at the rocker arms and springs for #4 especially the intake because of your description.

leak down test on number 4. and maybe the rest. i had one do that a number of years ago. turned out exhaust valve stem retainer was not installed correctly and it dropped the valve on top of the piston.

Managed to remove the valve cover, and this is what I found. No. 4 exhaust rocket bolt has sheared off.

https://ibb.co/LZRt06Y" rel="nofollow">

- Is it possible to pull the stud and replace without removing the head?

- I believe the studs are press fit?

- Could this have caused the knock sound? I would expect a tick not knock?

I saw a video of someone that tapped the broken thread on the stud a bit longer and use a nut and washers to extract it. Fitting a new one would probably require a press? Or tap the hole and use a threaded stud to replace?

I do have my previous engine's heads as spares, but it is a bit different (newer style with bolt down rocket gear). I assume mixing different heads is a bad idea? These are the spares I have.

https://ibb.co/b5nb9Dp" rel="nofollow">

Like you're thinking, you can do it right in the boat with the head on.

Kinda a tough spot to use a die, so if you weld a 1 1/2 inch or so piece of threaded rod you can pull it easier using techniques you probably saw in those videos.

I'd go for a threaded stud to replace it.

I'd guess that the pushrod randomly banging up, down and all around made plenty of noise 

Thanks

I'll look into both option to remove the stud.

Can I safely pull out the push rod, to check that it is not bent? Can removing the push rod disturb the cam followers below?

I am looking for a replacement stud.

Mine is 3/8 pressfit with a taper to 5/16 thread for the rocker nut. The hole in the pivot (half sphere) of the rocker is 3/8.

I can get a replacement (used) from a friend, but if has a 3/8 thread.

Could I use a 3/8 threaded rocker stud?

https://ibb.co/HBGbJHR" rel="nofollow">
https://nonprofitlight.com/pa/doylestown/bucks-county-free-library" rel="nofollow - bucks library

The rocker stud is a very common part for machine shops to replace.  Any local machine shop should have inventory on the shelf for purchase.   Parts stores may be able to order these parts in for you but an Engine Machine Shop that rebuilds heads would have them in stock.

On Chevrolets the common fix to making sure a press in stud stays put is to drill it and put a press pin in there so it can't ever pull out.

When larger cams are run pull out studs is a problem.

The studs are normally a life of the engine part, I would be looking for some issue that added pressure to the stud, sticking valve, coil bind on the spring, bad adjustment of the rocker arm.   Something changed the way it is designed to work or it would not break normally.   The wear pattern on your rocker arm and fulcrum seems a little odd, any chance the fulcrum/washer was upside down?  Curved side up.  I am wondering why the top side is showing edge wear, those do not move hardly at all with engine running.  Compare it to another fulcrum from another rocker and see what you think.

I do not know what year Ford went from adjustable rocker arms to fixed rocker arms.

I swapped my older 351W from stock 351W heads to older 289 Hi Po ported and Polished heads which gave higher compression and better performance.  I had issues with the push rod length, needed custom push rods to make it work, I broke a rocker arm while figuring things out but that was 35 years ago doing it with less experience.

Your present heads (the earlier heads) had the positive stop stud type rocker arms. You had the press in stud and you turned the nut till it ran out of threads. You didn't adjust it like you would adjust a typical Chevy.

Your spare heads (the later ones) are also non adjustable, you just tighten down the fulcrum bolt. 

You could use shims for "adjustment", but you couldn't adjust in the typical Chevy fashion.

I figure that you aren't loaded with machine shops and parts stores in South Africa that deal in old American parts, but there should be nothing preventing you from having an engine with 15 non adjustable rocker arms and 1 that's adjustable.

But.....with a 3/8 hole you can't put in a 3/8 threaded stud.

There are options for what you could do, like install a helicoil for a 3/8 stud or use a 7/16 stud that's 3/8 on the adjusting end.( or a replacement push in stud)

But it would be good to try to figure out what caused the problem to happen if possible.

Are both heads the same on your engine?  Maybe you are dealing with a previous repair where the heads were replaced as I did on my 1978 351W.

Non adjustable, positive stop stud type, in78 they went to the fulcrum bolt type heads like his picture of the 89 heads in his original thread shows.

Probably rebuilt by the machine shop, but everything looks stock and even though they resemble heads with adjustable rockers, they're not.

https://cylinderexchange.co.za/contact-us/

https://cylinderexchange.co.za/cylinder-head-reconditioning/

All he wants to do is replace one rocker arm stud without tearing things apart.

Even us backyard hack "hobbyist" types can handle that with a little skill and expertise

You must have been that kid growing that got his book bag thrown in the ditch everyday!

Your going to comment on every one of my posts?? your annoying for sure, are you the owner of this web site?

I see when some one else comments on this site your "ALWAYS" there!! get a life dude your not the only person in the world that has some info to share..

It's OK for you to pop in every once in a while, throw out some info and disappear I guess. Kinda like in this thread.

Then when Jody speaks and something gets added by me, it's time to get upset.

Look back in this thread, did I jump right in with something after you recommended a leakdown test?

Now as far as getting a life, mine's just fine, with some time available to help out here on CCF since I'm semi old and retired and don't mind passing on some of what I might know. Plenty of other things to keep me busy too.

Thanks Guys.

I really appreciate everyone's input. Keno has been deeply involved, so has the most background with regards to my engine woes

The pushrod is perfectly straight.

I was hoping to repair the broken stud without removing the heads. I'd like to use the boat ASAP. To do this, I just need a replacement stud (stock pressfit or some aftermarket threaded stud, and tap the hole). Is this a bad idea? I have a mobile stud removal guy that can assist. I just can't find a new replacement stud. I can only get a set of 16, that need a thread to be tapped in the head. I am waiting for more information from a local supplier.

Maybe the broken stud was over torqued? Or just metal fatigue? Can I test the value to make sure it isn't "stuck"?

A friend pulled this stud from his 302. Could I use it? Same 3/8 pressfit shaft but with 3/8 thread for the rocker nut (it seems like a locking nut).

Mine has a 5/16 thread, with the taper (positive stop).

https://ibb.co/3cnyVZX" rel="nofollow">

Thanks Keno. I'll give it a try.

One thing I noticed is that the "washers" at the bottom of the valve springs don't look stock.

2 have been trimmed to fit? And some of the others don't fit 100% flat. Ever seen this before? Could it be a problem?

https://ibb.co/2YZP2LF" rel="nofollow">

https://ibb.co/0Yp93t4" rel="nofollow">

It's OK for you to pop in every once in a while, throw out some info and disappear I guess. Kinda like in this thread.

Then when Jody speaks and something gets added by me, it's time to get upset.

"Look back in this thread, did I jump right in with something after you recommended a leakdown test?

Now as far as getting a life, mine's just fine, with some time available to help out here on CCF since I'm semi old and retired and don't mind passing on some of what I might know. Plenty of other things to keep me busy too."

Poof! i am gone! i wonder in a day of talking to nautiqueparts.com as well as dim.com customers you take the time to reference Correctcraftfan.com for information? lets see well you do not!! usually in daily correspondence this site gets referenced and even workable links for information passed on to correct craft customers. I do it , Woody also,  so?  PooF!!! Gone!!

Your help is always welcome and appreciated as far as I know.

I agree this engine repair would be very simple in the United States but this poor guy is trying to fix it in South Africa where they do not have access to stuff we consider common.

Mark

I don't see any signs of the valve spring coils binding.

So I have managed to pull the broken stud and fit the "donor" stud. This is not a positive stop stud.

https://ibb.co/R9Pyp0k" rel="nofollow">

Now busy reinstalling the rocker, and setting the valve lash - only for cylinder 8, exhaust.

Is it as simple as:

- Turn engine/crank by hand till intake #8 valve opens, then stop when it starts to close

- At this point #8 exhaust valve will be closed

- Tighten the rocker nut very slowly, while wiggling the pushrod up/down

- When the play is gone, that is 0 lash.

- Tighten another ~ 1/2 turn to preload

Tim is correct your washers//fulcrums under the rocker arm nut look very strange as did the one pictured early in this thread.  Those should see nothing touching them once adjustment is done.   Why do they have the odd marks on the top of the fulcrum?

I also noticed that every valve spring has the shims under them.   That is odd, it is normal to find some springs that need a shim on rebuild but never every spring?    

I hope you get it fired up and running well soon.

I also figure that if you have any more valve train issues or if you're having big doubts about the assembly of these heads  right now, then it's time to put your good set of 89 heads on it  

Thanks Guys.

The fulcrums (half sphere pivots) have circular marks on all of them. There are no extra washers on top.

MrMcD - when you say: "Those should see nothing touching them once adjustment is done." 

Doesn't the nut rest on top of those fulcrums?

Here is another photo (found online) of similar heads with similar marks.

https://ibb.co/R3r2Y0N" rel="nofollow">

Is there an easy way to check the valve train geometry?

TRBenj - "Double checking the installed height" - what does that mean?

If this doesn't work out, I'll definitely fit the old '89 heads.Maybe I should send them to a machine shop now to be cleaned up, to prepare for any future issues?

Could the "skew" valve spring shims cause extra wear on the valve guides?

When I cleaned the heads, there was some very fine metal "grit" in some old oil "sludge". Not shiny, but magnetic.

The thin (new) oil was clean.

The fulcrum fits snug, they will slip up and down but no side to side movement once on the stud.

Look at your new stud size compared to the studs in your head currently.   The new stud is larger diameter.

It's 3/8 at the bottom where it presses in and the threaded part is 5/16. Greg has already mentioned that. That's what his other 15 are like.

You tighten the nut down to the end of the threads and the fulcrum with the 3/8 hole fits on the 3/8 part of the stud....no slop

https://ibb.co/6WcXxG6" rel="nofollow">

I concur, geometry has to be checked. in early picture it looked like the valve stem was mushrooming over.

aiming 90 degree at mid lift would be best

Thanks Guys. Does anyone have a guide of how to check the geometry?

I saw a video which showed:

 - Top of the valve stem is colored with a permanent marker

 - Rocker installed

 - Turn motor

 - Check that the wear on the valve stem is in the center?

Is that good enough?

happens when rocker contacts points are squared up at mid lift

this is a rebuilt engine and has run through a machine shop? i would wonder how much surface was milled off if the block was decked and the heads re-surfaced??

Thanks Guys.

Unfortunately, I don't have much history on this engine's rebuild.

I bought it from a machine shop that fitted my marine hardware. Apparently the shop was involved in the rebuild of the bottom end. The shop told me the head was not rebuilt as it was 100%. The engine was used for about a year by a client (after"rebuild") and the client wanted to swap to a higher performance engine and sold it (to me). This is the same shop that said the timing was 100%, when it had a 302 cam and the timing setup for a 351, and also did not have an eccentric properly installed to drive my mechanical fuel pump, even when I explicitly asked. So I really don't have much faith in anything they say.

So, as far as I am concerned, everything about the engine is "unknown". The few days that it ran, it was running great though.

It could be a deep one or a shallow one 

Since you have the engine, got through some problems getting it together and knew how it ran before the issue, I'd say using your judgement on what to do is the best thing

I think the engine ran really well. Idled smooth and sounded just like my previous 351w.

I think I'm gong to try check that the valve geometry is okay - 90 degrees at mid position of valve.

Then fire it up.

I'll run it for a day, then remove the valve covers see if anything looks suspicious (metal filings, etc).

Might also do an oil change and check the oil, cut open the oil filter and inspect.