New 4.3, Starboard Riser 30F hotter on muffs after engine reaches temp.

[THenning]

So I have my new 4.3 in from Atlantic Motors. 2 Barrel Mercarb.

Ole Engine Serial was 0M078233

New circulation pump, New impeller and housing (quicksilver), new thermostat (Mercury from marina next door), New water Tubes in the out drive (quicksilver).

Flushed and inspected Manifolds. Inspected Flappers in Exhaust A-OK As well.

Started engine and set timing. Starboard Riser is cooler than port until T-Stat opens, then starboard riser heats up till is is 30 degrees hotter than port. IR Thermometer reads 133F on Starbort and 99F on port.

It seems like the hose going to the bottom of the multi piece manifolds (not the batwings) stay water supply temp until the thermostat opens up, then the starboard feed to the exhaust is only getting warm water while the port is getting the cold water. I used a wire and a flashlight to check for blockages in the T-Stat housing, there isn't any.

Is this normal? OK?

Also, Video below, is this much valve noise normal for a freshly rebuilt engine?

https://youtu.be/J5IMpVTNKhQ

 

[Searay205]

That is a ton of noise. What is your oil pressure. Sounds like valve lash set incorrectly. As far as temps some variance is normal as long as both stay below 140 F no worries.

 

[tank1949]

So I have my new 4.3 in from Atlantic Motors. 2 Barrel Mercarb.

Ole Engine Serial was 0M078233

New circulation pump, New impeller and housing (quicksilver), new thermostat (Mercury from marina next door), New water Tubes in the out drive (quicksilver).

Flushed and inspected Manifolds. Inspected Flappers in Exhaust A-OK As well.

Started engine and set timing. Starboard Riser is cooler than port until T-Stat opens, then starboard riser heats up till is is 30 degrees hotter than port. IR Thermometer reads 133F on Starbort and 99F on port.

It seems like the hose going to the bottom of the multi piece manifolds (not the batwings) stay water supply temp until the thermostat opens up, then the starboard feed to the exhaust is only getting warm water while the port is getting the cold water. I used a wire and a flashlight to check for blockages in the T-Stat housing, there isn't any.

Is this normal? OK?

Also, Video below, is this much valve noise normal for a freshly rebuilt engine?

https://youtu.be/J5IMpVTNKhQ

Years ago, I experienced similar heat variations on Alphas. I suspected it was due to MC plumbing designed, because of the new manifolds/risers that I had installed were clear and free of any crap. My inferred thermometer indicated similar to yours. To test, I removed hoses to risers and manifolds and attached garden hose (motor not running). Water went through both sides like corn through a goose. Who adjusted valves? Factory?? It is not uncommon to have to readjust Chevy valves.

 

[THenning]

Oil Pressure is at 44PSI

Valves were installed at Atlantic Marine where I bought the motor.
Motor I bought is:

• Assembled Block and Heads With All New Internal Parts
• Oil Pan
• Timing Cover
• Valve Cover

Intake manifold is from old motor, as well as T-Stat housing, Carb, and all engine accessories except for the circulating pump which is also new from Atlantic marine. I have the old pump, it isn't bad but I wanted to make sure everything was fresh.

After I notices the temp difference, I pulled the hot manifold and riser, ran my garden hose through it, everything flows free. I also stuck my hose down the pipe above the flapper to make sure water flowed out the back freely, it does. Reinstalled and have the same temp difference.

No valve adjustments were done since the engine came out of the crate. Valves were already assembled and covers were on.

 

[Rick Stephens]

Valves on a Vortec are just torqued down anyway. Hard to get them wrong. They aren't adjusted like older chevys. Temp variation is normal. Does your thermostat housing have the check balls on the outlets to the manifold hoses? Might check and make sure those are freely moving and just go by your temp gauge moving forward.

 

[THenning]

No check valves. I do have a thermocouple with Extended wires, Maybe I just tape them to my risers for the lake test/First 20 hours. What temp should I be concerned on the risers if the sending unit reads 170?

 

[Searay205]

That engine does not sound acceptable. It excessive ticking. Either they didn't torque the bolts and adjusted like older engine and there is excessive lash or the lifters are leaking down. My vote is something in the valve train is not adjusted or tightened correctly. did you send video to engine builder?

 

[Searay205]

Interesting read:
This brings me to my last suggestion. I've saved it for last because it's the least likely to apply to your situation. Some 4.3L Vortec engines have experienced premature main bearing failure, following an intake manifold R&R. In 1996, the Gen 1 V6 engines were reengineered to incorporate vertical intake manifold-to-cylinder head attaching bolts. If the intake manifold bolts are overtorqued, the crankshaft main bearing bores can become distorted, eliminating the necessary clearance for proper oil film. If the intake manifold has ever been removed from any of the engines you're dealing with, you may want to verify that the procedure was conducted properly. Distorted bearing bores, and subsequent bearing failures, are a much bigger problem than some noisy lifters.

 

[THenning]

I did send the video to the engine builder. Hoping for a reply today. Intake was swapped out, I'll have to get the torque wrench back out and double verify.

 

[Boater31]

I was reading on the net from a different forum from Mercruiser tech support,
"The water coming out of the engine block exits only on the starboard side of the engine. Therefore the starboard exhaust manifolds and exhaust elbows will be warmer than the port exhaust manifolds and exhaust elbows. This is normal for your engine. If you have a 160 degree thermostat installed the temperature of the exhaust manifold on the starboard side of the engine can get up to 176 degrees under normal operation after the engine has reached 160 degrees. The temperature of the exhaust manifolds and exhaust elbows can also vary depending on the temperature of the water, the ambient temperature and the humidity."


​​​​​​My temps are almost exactly the same as yours. Little higher after long run.

 

[Furbird]

I've seen that reply as well but I'm not entirely sure what they mean by that. When my boat is on the ears, water comes out of both ports on the gimbal. Maybe I'm reading something wrong?

Regardless, I have about a 15 degree temperature difference between port and starboard and everything I've read says that's normal. However, that valve tap is NOT normal. That engine DEFINITELY has something going on with it. It's almost like it's not getting proper oil to the lifters.

 

[tank1949]

I never read anywhere that motor had vortx heads. Perhaps I missed something? Anyway, pop off valve covers and see if rocker arms are excessively loose. You will know real quick!

 

[Rick Stephens]

I never read anywhere that motor had vortx heads. Perhaps I missed something? Anyway, pop off valve covers and see if rocker arms are excessively loose. You will know real quick!

He has the late model plastic Vortec valve covers...

I've seen that reply as well but I'm not entirely sure what they mean by that. When my boat is on the ears, water comes out of both ports on the gimbal. Maybe I'm reading something wrong?.

The idle relief ports in the gimbal housing split off the exhaust after the Y pipe comes together with all the exhaust. So how it comes out of those ports is not reliable to which manifold supplied.

 

[THenning]

We have a solution!

I didn't have a gantry crane or strong tree, so I paid a boat yard to hoist the old engine out, swap the coupler, flywheel and starter. Then drop the new engine in. I kept the rest of the parts in my garage while they did this. I did a little bit of hunting with a mechanic's stethoscope. Marine Mechanic didn't quite put this plastic cover near the starter on right. See photo, #8. This little plastic cover was hitting the teeth on the flywheel and bumping against the bell housing. REALLY sounded like lifter noise.

Began break in on the lake tonight.

Thanks as always for all the informative information. I appreciate all the feedback on the cooling system, too.

As a side note, 60PSI Oil pressure at 3300 RPM notmal for the 4.3 or would you take a tiny bit of oil out?

~44 PSI at idle. Good levels.

 

[Rick Stephens]

Taking oil out won't change your oil pressure, unless you take too much and it sucks air. Leave it. It's fine. OIl pressure is determined by the type of pump, the spring in the relief valve in said pump and less so by how tight the motor is - at least until the motor is crapping out and the oil pressure can't build up.

 

[THenning]

Thanks a ton!

Had an oil pressure issue on one of my bikes from a little too much oil once. Figured it was prudent to ask.

I'll keep an eye on the Engine with the normal sending unit and a thermocouple with 2 probes. Time to get back on the water.

 

[achris]

Variations in the elbow/manifold temperatures are to be expected. As my flerf friends are prone to saying, 'water finds its own level'... In this context, if there is any variation in the 'resistance' path of the water flow out of the thermostat housing and into the manifolds, the water will follow the 'path of least resistance'. And that could be something as small as a list on the boat while in the water, or on the trailer.

Chris......

 

[tank1949]

You sending mechanic bill for lift? I would!