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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Dan75k20 on March 27, 2014, 10:16:02 am
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So I think my timing chain went. My truck stalled after i pulled out from a stop sign . I just ordered a comp cams 12-235-2 4x4 extreme cam lifters and a cloyes double roller timing chain Monday and it arrived from summit Tuesday same day the truck shut down also i have spark and fuel
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Well i pulled the dizzy and the gear was eaten i dropped in another dizzi battery almost dead gotta charge it and see what happens
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this is when I'd be wondering why that gear was eaten up before I started it.
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this is when I'd be wondering why that gear was eaten up before I started it.
Not only that but all that material is now inside your engine. If your dist. gear got ate up, I would be investigating and tearing down to see why, the gear that runs the gear on the dist. is probably ate up too.
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So im going tear it apart tomorrow and drop the pan clean it all out and see what happens i have a 305 0ut of a Monte Carlo ss if its too bad that's going in
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trying to post pics from my phone says there too large , well any way I tore the engine down has a worn intake lobe and a worn exhaust lifter pulled the pan a few metal shavings from the distributor were in there good thing It just shut down when it did! so I cleaned the engine with engine flush (not running) pulled the cam it was a comp 12-246-3 .487/.490 110 lobe separation 274/286 duration had a 750 holley dual feed on it .now I have 882 heads 76cc chamber flat tops with 4 valve reliefs I should have 9:1 compression edelbrock performer edelbrock 1405 600 cfm I swapped the cam for a 12-235-2 0.477/0.462 111 lobe separation 254/262 duration runs a heck of a lot better drove 80+ miles Saturday driveability is much better
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What specifically do you notice that makes driveability so much better? I'm very interested in the differences between those cams and those carbs.
Note that you should be running higher-zinc oil or a zinc additive with that new cam. Also you should change out the oil after a couple hundred miles to clear any extra crap out of there and because of breaking in the new cam and lifters.
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i bought the truck with the engine in it with the new 750 holley on it tried to tune the holley ,it needed rejetted it ran rich as can be primary jet size was too big so i installed a 600 edlebrock 1406 ran a little on the lean side though(no jet or metering rod changes just out of the box). i put the 750 on craigslist and ended up trading for a brand new 1405 and a trick kit the edelbrock was set up for a 355 with an a/f meter so i haven't had to change jets or metering rods, now as far as driveability as far as cam change is concerned with the 12-246-3 cam and holley 750 it just wanted to make power in all the wrong places even with the edelbrock 600s gas milage went from 6-9 and that's it it was just as fast as it is now even with a slightly smaller cam.the 12-246-3 makes peak torque at 3900 rpm and peak hp at 5900 rpm so this isn't a drag truck its my dd with the 12-235-2 im getting 12 city 14 highway and the idle is better the torque comes in at lower rpm the truck just seems to drive a lot better on the street it dosent want to be at such a high rpm. now if it wasn't my dd and was a 2wd 1/2 ton with 4;10 gears that cam and a 750 with a single plane intake that would run awesome but not a 3/4 ton 4x4 with 33s and 4:10 gears just my opinion