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Old 11-12-2010, 02:28 AM   #1
BadaSs_Cal
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newer 250 has no guts.

My original 250 one of the lifters went out. So we managed to get our hands on a newer 84 250. ( I know I know, integral head.. but it was free) Well cant seem to get the truck going past 30 mph. Its the strangest thing. First gear is all fine and dandy.. then second gear will seem to stall out if gassed super fast, if we baby it we can get it into third but it seems like its reving really high and get severe windage? What do u guys think? Any advice would be appreciated thanks.
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Old 11-12-2010, 11:52 AM   #2
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Re: newer 250 has no guts.

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I don't know if you have checked the compression on it but that's the first thing I would do. Plugged fuel filters will cause that type of symptom too. Replace the one in the carb inlet, plus any others you might have. Just some things to check...

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Old 11-12-2010, 11:59 AM   #3
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Re: newer 250 has no guts.

hows the fuel pump... sounds like it may be starving for gas with load on it...
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Old 11-12-2010, 12:58 PM   #4
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Re: newer 250 has no guts.

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Oh, and don't forget the fuel strainer sock on the end of the fuel pickup tube. (it's in the fuel tank)

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Old 11-13-2010, 01:15 PM   #5
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Re: newer 250 has no guts.

Quote:
Originally Posted by BadaSs_Cal View Post
if we baby it we can get it into third but it seems like its reving really high and get severe windage?
This is the part that has me scratching my head. What kind of transmission do you have?

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Old 11-13-2010, 07:51 PM   #6
292farmer
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Re: newer 250 has no guts.

was the condition of the motor known before swap? i'd do a tune up in cluding all filters, i agree sounds like a fuel delivery problem, if the old one ran fine then the fuel tank one should be good but should still check also whats the condition of the fuel pump? maybe its not putting out enough psi to last at higher rpms/fuel loads.
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Old 11-13-2010, 08:10 PM   #7
basemodel67
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Re: newer 250 has no guts.

Maybe it's the tranny...
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Old 11-13-2010, 08:57 PM   #8
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Re: newer 250 has no guts.

^^^ not saying your wrong, but wouldn't a tranny problem have shown up with the previous motor? that being said were any tranny lines hit(auto) or clutch miss adjusted? maybe clutch has enough to hold in first, but as vehicle speed/load increases it loses grip hence the hi rpm sound?
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Old 11-17-2010, 02:12 AM   #9
BadaSs_Cal
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Re: newer 250 has no guts.

Hey guys thanks for the all the feedback, I think it might be a combination of a lot of things. ( Mostly I was too excited buying my first project truck, that turned into a daily driver) I will try to start from the beginning, maybe you guys have some ideas or input that may help me out. I'm learning so bare with me.

1. Even when I first got the truck there was some lifter noise from start up, always started strong and sounded good ( except for the constant ticking noise) but after it warmed up a bit it went away.

2. The truck ran fine on the freeway up to about 55 then you could feel the tranny area knocking around pretty hard, so I always kept it at low speed.

then the trouble started.

I lent it to my father in law for a week so he could do some light trailer towing. We'll hes hard on his cars. Drives fast, starts fast, drove my truck around town like he was a teenage boy.
Well thats when I got the truck back and the tranny felt like it was slipping in and out of gears. EVEN WHEN IT WAS NOT IN GEAR! I was lost so I let it sit

And he borrowed it again.

That when I had to go pick him up because the motor felt like it was knocking like crazy, but it felt like it was shifting fine. No high rpm noise, just real bad knock coming from motor.

So we pulled it out and replaced it with a 84 250 motor. Leaks a little from the rear seal, but other then that turned freely and was in good shape.

Another problem we had was we started pulling smog stuff of the new motor and I know theres some important vacuum lines that were not hooked up, but just plugged. So now thats everything I think.

I was thinking of just finding a driveable cheap 350 setup out of a 73-87 pickup and using it to replace the whole drive train in the truck in one big swoop. I dont know, what do u guys think?

edit: the current transmission is a 4 speed ( including low gear ) the PO converted to floor shift from column shift. Looks like it was a rebuilt one, he said it was rebuilt, but it could of just been painted.
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66 Gmc 1 ton. Long Step 351e V6
69 1/2 CHEVROLET (now a shortbed) LONGBED!:devil
61 Shortbed Fleetside 1/2 ton.. in progress

Next a 50-53!

MY BUILD THREAD
http://67-72chevytrucks.com/vboard/s...d.php?t=447926

Last edited by BadaSs_Cal; 11-17-2010 at 02:19 AM. Reason: more info
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