Author Topic: vortec headed 383 has no power  (Read 20481 times)

Offline rich weyand

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Re: vortec headed 383 has no power
« Reply #15 on: May 19, 2014, 02:30:27 AM »
Cam timing and ignition timing are two different animals.  One times spark against the pistons, the other times valve events against the pistons.  That being said, for street use the cam should be timed at zero degrees by the marks unless the instructions with it specifically call out differently.  The best timing for the cam should be handled in the grind right out of the box.
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift

Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #16 on: May 19, 2014, 04:31:57 PM »
ok heres what a machinist told me today over the phone . i explained to him the problem im having and he said even if cam is wrong it would either make power on top or on bottom .he asked me how does it crank ? fine i said .then he asked was it balanced . it said yes , but i had 350 pistons .i replaced them with 383 pistons .(guy who assembled motor took them to machine shop and had them  switched  out .) he told me thats the problem and it got to come apart to see whats damaged and rebalanced an line hone block if needed .this makes sense to anybody . my first motor im learning alot from my mistakes and trust in peole  >:(
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Offline Dan75k20

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Re: vortec headed 383 has no power
« Reply #17 on: May 19, 2014, 04:52:02 PM »
So wait a minute the engine was balanced with the 400 crank rods and stock,bore pistons

Offline 74k20

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Re: vortec headed 383 has no power
« Reply #18 on: May 19, 2014, 05:18:41 PM »
When I 1st fired up a new bbc 396 in my Chevelle, it didn’t fire right up.  Played with timing and got it running good, but BY EAR ONLY.  Couldn’t get the timing-light to make any sense.  My headers also started glowing and baked off some ceramic coating on my new headers (grrr).  So I ended up leaving it timed by ear/feel, and ran it for a while.  Started fine and GREAT, with NO power at all.  Struggled to even get a chirp out of the tires, but did run smooth.

Ended up finally taking off the front timing cover…to discovered the cam was 3 teeth off from the dot-to-dot alignment.  I watched the guy install the cam using a fancy degree wheel, but I didn’t watch him in detail and assumed he knew what he was doing.  WRONG.  So I put it dot-to-dot….WOW…. have trouble keeping the tires from NOT spinning now.

I'm about to swap in a nice sb400 in a couple weeks, so I'm nervous about this start up also.  I'm watching this post to learn from.  Good luck.

Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #19 on: May 19, 2014, 05:50:25 PM »
No ,they were .030 dished 350 pistons ,i did not know there was a diff in height between 350and 383 pistons . When i found out they came out block about .100 .then realized after talking to summit tech guy .shop that clearanced motor never  fliped block over to check because ,he thought i bought a complete rotating assembly .@74k20 ,thats exacly what mine is doing ,but machine guy thinks or more like gaurantee this is whats wrong its out of balance with the new pistons
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Offline LeftysRodandCustom

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Re: vortec headed 383 has no power
« Reply #20 on: May 23, 2014, 01:21:39 AM »
Cam timing and ignition timing are two different animals.  One times spark against the pistons, the other times valve events against the pistons.  That being said, for street use the cam should be timed at zero degrees by the marks unless the instructions with it specifically call out differently.  The best timing for the cam should be handled in the grind right out of the box.

Rich that makes a lot of sense now that you said it that way. Thanks

Offline Dan75k20

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Re: vortec headed 383 has no power
« Reply #21 on: May 29, 2014, 03:38:04 PM »
Any luck with your 383 ??

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Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #22 on: May 29, 2014, 06:14:57 PM »
Just took it to shop today ,guy gonna run compression test on it .before looking at cam index.i read that a 383 compression  should be about 185-190 .howard 's cam told me that it should be installed " straight up ".the +4 degrees in the cams 104 ICL with 108 LSA already, no need for additional advance .soon as i find out i will update you all .
.
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Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #23 on: May 30, 2014, 08:17:35 PM »
Little test i done ,put truck on lift and held brakes and floored it .engine stalls down a little .put in park and floored it ,it didnot stall any .guy told me he thinks converter is bad thats why it stalls down in gear if u give it alot of gas .he said he will do compression test tonight .if it fine he said it the converter .We will see. Anyone ever had any bad converters that made ur motor a dog .
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Offline LeftysRodandCustom

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Re: vortec headed 383 has no power
« Reply #24 on: May 31, 2014, 12:47:40 AM »
Here's a dumb question for ya, was the converter full of fluid when it was first installed?

Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #25 on: May 31, 2014, 02:25:09 AM »
Yes ,
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Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #26 on: June 02, 2014, 12:51:17 PM »
UPDATE ..one problem was i had wrong spark plugs in .regular tbi heads use a short reach plug s(thats what i had ) vortec and aftermaket vortec use long reach plugs .i had short ones .the correct ones are APP606 autolites .about $4.49
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Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #27 on: June 02, 2014, 06:33:37 PM »
Still needs a stall though ,but runs alot better ,did get it to turn those 22's loose .loving my shortbed right now  ;D
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Offline 305chevy c-10

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Re: vortec headed 383 has no power
« Reply #28 on: June 12, 2014, 10:28:40 PM »
update .one day out the shop and white smoke everywhere .i did a mean power brake BURN OUT  with my new 22-2800 boss hog converter and when i got home white smoke comes out both tail pipes  like a train .i think i blew a head gasket . CRAP  :o :'(
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Offline rich weyand

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Re: vortec headed 383 has no power
« Reply #29 on: June 12, 2014, 11:11:35 PM »
BOTH tail pipes?  If you have full duals with no crossover pipe, you blew both head gaskets.
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift