problem after engine rebuild
Thread Starter
Staging Lane
Joined: Nov 2001
Posts: 92
Likes: 0
From: San antonio
problem after engine rebuild well i rebuilt the engine and jus put it back in the car and fired it up but it will turn off rather quikcly. i put everything back to stock. i use to have mti stage one heads which were milled and i put stock heads back on the car but i think i used the shims that i had for the rockers on the stockers would this cuase a problem? when the engine is turned on the valvetrain sounds very noisy and the scanmaster shows alot of knock when the car is turned on. it only stays on for a couple of seconds and than shuts itself down. i think i installed the cam whith the engine at tdc but im not sure? what do the marks on the crank sproket and cam sprocket look like?
Re: problem after engine rebuild The cam gear has a pretty obvious dot on it, and the crank gear has a not as obvious (but still there) dot on it. Assuming you lined these 2 dots up, your cam alignment should be OK. But if you did not line these 2 dots up (say, for example, you lined the cam dot with the crank keyway), you've probably bent valves. A friend of mine here did that - lined the cam dot with the crank keyway. Bent 3 intake valves - found by doing a compression test. Even after he found his error (dot-to-dot) and corrected it, the car would not run very well at all until he replaced the valves.
As for the shims & whatnot, it would be best if you restored original rocker arm geometry if using stock heads. 7.4" pushrods, stock rockers, and stock rocker arm mounts.
Good luck,
Andrew
As for the shims & whatnot, it would be best if you restored original rocker arm geometry if using stock heads. 7.4" pushrods, stock rockers, and stock rocker arm mounts.
Good luck,
Andrew
Thread Starter
Staging Lane
Joined: Nov 2001
Posts: 92
Likes: 0
From: San antonio
Re: problem after engine rebuild oh well im pulling the heads off to get ported and i jus ordered the g5 cam package so i guess im keeping my car! ill see if it was dot to dot when i pull the heads off.
TECH Junkie
Joined: Nov 2001
Posts: 3,604
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From: Los Angeles
Re: problem after engine rebuild The dots are definitly pretty obvious. If you didnt see a round circle on the crank gear and line it up with a round circle on the cam gear, then things definitly coulda bent. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />
Does it sound bad for the few seconds it does run?
Does it sound bad for the few seconds it does run?
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Thread Starter
Staging Lane
Joined: Nov 2001
Posts: 92
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From: San antonio
Re: problem after engine rebuild the valve train sounds pretty loud all i know is the when i did line it up it wasnt with any circles it was with the line on the crank gear i know the number 1 piston was not all the way up though i feel like an idiot right now but ill find out when i pull the heads off again.
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Verdad Gallardo TECH Junkie
Joined: Nov 2001
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From: Los Angeles
Re: problem after engine rebuild </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ooblockxburneroo:
<strong>all i know is the when i did line it up it wasnt with any circles it was with the line on the crank gear </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dot to line = <img border="0" alt="[whiner]" title="" src="graemlins/gr_cry.gif" />
Dot to dot = <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />
Some valvetrain noise *is* normal when you first start it up due to the lifters, but that should mostly go away after 3-4 seconds.
<strong>all i know is the when i did line it up it wasnt with any circles it was with the line on the crank gear </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dot to line = <img border="0" alt="[whiner]" title="" src="graemlins/gr_cry.gif" />
Dot to dot = <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />
Some valvetrain noise *is* normal when you first start it up due to the lifters, but that should mostly go away after 3-4 seconds.
Re: problem after engine rebuild Yep, my friend did dot to line. <img border="0" alt="[whiner]" title="" src="graemlins/gr_cry.gif" /> That's how he bent valves.
He actually drove it, though, after re-aligning the dots. It didn't idle worth a crap, and you had to keep giving it gas to keep it going.
If you pull the intake manifold, and pull the rocker arms, you can look down in the intake ports at the valve seats. For his, it was pretty obvious that valves were bent - we could see combustion chamber with no rocker arms installed! Also had some nice 'eyebrows' cut in to the pistons too. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> But those seem to not have done any harm.
-Andrew
He actually drove it, though, after re-aligning the dots. It didn't idle worth a crap, and you had to keep giving it gas to keep it going.
If you pull the intake manifold, and pull the rocker arms, you can look down in the intake ports at the valve seats. For his, it was pretty obvious that valves were bent - we could see combustion chamber with no rocker arms installed! Also had some nice 'eyebrows' cut in to the pistons too. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> But those seem to not have done any harm.
-Andrew
Thread Starter
Staging Lane
Joined: Nov 2001
Posts: 92
Likes: 0
From: San antonio
Re: problem after engine rebuild ok i pulled the front cover off and and sure enought the cam was not lined dot to dot. i pulled the rockers off and the pushrods and everything looks fine. i accidently put the shims from my mti heads that were milled back on my stock heads with stock lenth pushrods. do you thikn this could have prevented the valves from being damaged since the rockers had .30 higher clearencing from stock. i might not pull the heads off cuz im not sure if there being ported for sure yet and i dont want to pull them off and have to go buy new gaskets and bolts again. let me know what you all think
Re: problem after engine rebuild Agreed, compression or leakdown test. On my friend's car, 3 of the cylinders on the passenger's side had no compression when cranking. The other 5 cylinders were OK - so he only replaced the 3 intake valves in that one head. Car runs like a mad dog now. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Good luck,
Andrew
Good luck,
Andrew
