Thread: 348 Running warm

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Originally Posted by 36 sedan

Sorry, didn't mean it to be a lecture.

No really, I wasn't be sarcastic, I really do understand better. Thanks

I have got one small thing to check, this problem happened to me, badly and caused me a ton of grief, if you happen to have a similar hi flow thermostat and they dont have room to expand, or the water doesnt have room to go around the outside, which could be a possibility on some motors https://m.youtube.com/watch?v=mvZ1UunKGqI

Originally Posted by Matthyj

I have got one small thing to check, this problem happened to me, badly and caused me a ton of grief, if you happen to have a similar hi flow thermostat and they dont have room to expand, or the water doesnt have room to go around the outside, which could be a possibility on some motors https://m.youtube.com/watch?v=mvZ1UunKGqI

Great info! However, it appears he is installing the stat upside down???

Originally Posted by 36 sedan

Great info! However, it appears he is installing the stat upside down???

Yep, the "pill" goes toward the motor.

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I. Like using straight manifold vacume the ports on the carburetor that are intended for timing limit the vacume at idle so being more retarded burns more fuel and is a little better for pollution but a retarded idle makes engine run hotter. If you don't have an adjustable vacuum advance pull cap off and make a stop so to limit advance to 40 degrees at idle or cruising
There is a good thread on this but I am on the road try searching vacuum advance.
It explains it better than I can.

Not aware of any decent reverse flow waterpumps for 348-409-----------did you just change the impeller????? If so, that won't work as the impellar must not only fit the housing but inlet and exits must be arranged compatible to the impeller flow direction.

How many amps does your electric fan pull???????

See Post #2 in your earlier thread - 348/409 reverse flow water pump help

Originally Posted by rspears

See Post #2 in your earlier thread - 348/409 reverse flow water pump help

I am going to check the timing and carb more and then check the flow of the pump. I'm not going to go through to much more work with buying $400 dollar pumps or changing everything to a v belt setup if the pump isn't flowing good enough. I have a reversed impeller in it right now, I was in to this thing so deep that was about my only option at the time. Tonight I drove it when it was about 75-80 deg and the temp never broke 200, I might just limp it along this summer and drop a 5.3 in for a winter project. I wish I could go back in time and talk to the young man who thought this whole 348 setup was too cool to pass up

It’s a little difficult to see from your pictures, but it doesn't look like you're using a bypass hose with your current setup. I know there are folks that say the bypass hose isn’t necessary, but I can tell you from personal experience overheating problems can occur without the little rascal installed.

Hopefully your issue may be simpler to fix than you think … it may be worth a try.

Originally Posted by Dan J

It’s a little difficult to see from your pictures, but it doesn't look like you're using a bypass hose with your current setup. I know there are folks that say the bypass hose isn’t necessary, but I can tell you from personal experience overheating problems can occur without the little rascal installed.

Hopefully your issue may be simpler to fix than you think … it may be worth a try.

I am just about afraid to ask this because of embarrassment, but is that necessary? I found a fitting and some hose this morning and I am going to put one on right away. I need to drive it about 100 miles today for some exhaust and run some errands.

Originally Posted by 53 Chevy5

I am just about afraid to ask this because of embarrassment, but is that necessary? I found a fitting and some hose this morning and I am going to put one on right away. I need to drive it about 100 miles today for some exhaust and run some errands.

If you get a chance to install the bypass before your trip today, please provide an update after you return. I'm hoping that you'll be pleasantly surprised. And 36 sedan provided a great answer as to why the bypass is needed (Chevy went to the trouble and expense for a reason).

Good luck!!

Originally Posted by 53 Chevy5

I found a fitting and some hose this morning and I am going to put one on right away.

It's hard to make that tight bend with a piece of straight hose without kinking. Using a pre-bent 90 trimmed to length makes it an easier job....

4 C notes is a lot for a water pump, but it's a lot less than a new motor.

Do you have visible flow in the radiator with the engine hot? Beyond a gross timing issue, I think it's the culprit, having read the thread.

The previously mentioned oil cooler is cheap, and you can relocate the oil filter at the same time.

You've come so far, it seems a shame to give up now.

WOW! Nice catch Dan J.

Yes, that was a good catch!