New 350 overheating during break-in

[79BIG10]

Originally Posted by Slonaker

Brandon:

I'm still not sure what you are saying, but I will definitely check it for leaks. Everything fit nice and tight, so hopefully I won't have any problems.

The bushing I had once it screwed onto the threaded bushing it was tight. Then the probe would not bottom out but it would move back and forth inside the bushing. If someone can post a pic of it I could explain it better.

[swervin ervin]

Sorry Brandon, even I don't have a clue what you are trying to say.

[larry may]

are you talking about a 1/2 inch to 3/8 pipe bushing to screw into the intake then insert the tempeture bulb through the installed bushing then the threaded peice on the bulb tube screw it into the 1/2x 3/8 bushing. The one in the manifold may not be 3/8. To recieve the bushing on the tube from the temp gage. Is this something close to what you are asking?? or are you putting the bulb into the thermostat housing?I do not have a picture.

[swervin ervin]

larry,

I was just messing with Brandon. He and I go a long way back. I know what he's talking about, I think.

[Slonaker]

I think Brandon was talking about a mechanical temp gauge. If that was the case, it would explain why I had no idea what he was talking about when trying to figure out the sending unit on my stock gauge.

I'm still gonna take his advice and check it for leaks, though. I'm never quite comfortable threading stuff together without teflon tape. Chevy has an electrically conductive sealer for gauges and stuff, but it is $20 for a tube!

Slonaker

[84slopwaggin]

Hey what about the stock unit that screws into the side of the head. Thats the part that was connected on my stock unit, although I don't think it was operating properly. Is this part only accurate on 305 heads or will it or a new one like it work properly on a set of 350 heads. I wouldn't think it would make a difference.

[swervin ervin]

I believe the sending units are setup to work with certain gauges, not heads or engines. Reason the unit in the 305 head wouldn't work in the new 350 head is because of the size hole in the heads. The 305 head has a smaller hole to fit the stock unit. The 350 head has a bigger hole, thus the need for the bushing/adapter. I had to do the same thing with my Edelbrock heads.

As a side note to all my picking, Brandon is speaking of a mechanical gauge sender which has bulb type thing on the end which senses the heat for the gauge. The bulb type thing is what he was saying flopped around if the correct bushing wasn't used. It must have a seat/lip deal in the bottom of said bushing so it fits tight and bottoms out so coolant don't get past it and bleed through the threads. This bushing isn't pipe thread like the one needed for the electrical sending unit.

There. Is this what you were trying to say Brandon.

[79BIG10]

Originally Posted by swervin ervin

As a side note to all my picking, Brandon is speaking of a mechanical gauge sender which has bulb type thing on the end which senses the heat for the gauge. The bulb type thing is what he was saying flopped around if the correct bushing wasn't used. It must have a seat/lip deal in the bottom of said bushing so it fits tight and bottoms out so coolant don't get past it and bleed through the threads. This bushing isn't pipe thread like the one needed for the electrical sending unit.

There. Is this what you were trying to say Brandon.

That's right Mike. You said it better than I could. And yeah we do go along way back.

[84slopwaggin]

I was wondering if the stock gauge would register correctly with the sending unit that fits the 350 head, becuz I'm not sure mine did when the engine was running. I did have some mechanical problems such as burnt #6 intake valve and really low oil pressure after the truck reached operating temp, so that could have lead to my slightly over heating problem. I was planning on taking the sending unit to the parts house and buying one just like it to install on my new engine and see how it registered.

[piecesparts]

As I read all of this about the sensing unit. I begin to wonder "Just what type of mess you have in your hand"? The sensing units that I have seen are all one piece where the temperature bulb has the threads designed right on them and there is no inserting anything. (It is all one piece)
If the hole is a 1/2" pipe thread, then get a brass 1/2" to 3/8" bushing and thread it onto the sending unit. Once that is done then screw it into the 1/2" hole in the intake or head. After that connect the wire to it and fill with water. I am missing what all of the confusion is on this.

If the sending unit is NOT matched to the gauge the reading will be off from the proper numbers. So it may take some trial and error in finding the right one, depends on how good the parts guy is.

[swervin ervin]

There is a difference between mechanical sending units and electrical. Mechanical has the bulb made to the tube going to the gauge. Besides, no one has a mess any longer.

[piecesparts]

really? Darn it--here we go again...

[84slopwaggin]

well I have the stock factory gauge that comes with the truck. The sending unit screws into the side of the head no bushing needed. I guess it's the proper setup. Like I said I had other mechanical issue going on as well, so that might have been contributing to my engine running slightly hotter than normal.

[piecesparts]

see, there is too a mess.....

[boxrodz]

Originally Posted by Slonaker

...
Well, the new sender was the problem. I installed the old sender with the adapter, and now the gauge reads acurately. It warmed up to 195 degrees during break-in, and then never went beyond it. It is actually running pretty good.

I got pulled over by the Selma PD last night when I went on my test drive. A police car that was hiding under an overpass saw me at a stop sign on the access road. He turned on his headlights, and came screaming up within 50 feet of me, then stopped. He just sat there, so after 15 seconds or so, I pulled out. He followed me up onto IH 35, and pulled me over. WTF?

Another police car showed up, and they asked me a bunch of questions about why I was out, where I came from, and where I was going. I'm sitting there looking like a hooligan on the side of the interstate, in a truck with no hood. They finally told me that my truck was an EXACT match to one seen leaving several burglaries over the weekend. Just my luck.

Thanks again to everyone who helped.

Slonaker

Congrats, Slonaker.

Good to hear you got the problem solved with some help here.

And you have a good story to remember your first drive.

Good job.