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Username Post: Late valve timing        (Topic#209268)
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-09-09 05:19 PM - Post#1626397    

Ok my truck is still running bad with the new motor. vac guage says intake leak or heat riser leak or bad valve timing. I threw in a new set of intake gaskets ran through the proper routine etc torqing all bolts to specified torque in the proper sequence. After looking at the old gaskets and measuring them with a set of calipers they were all uniform and there wasnt any signs of a leak. My truck doesnt have a heat riser so that is out. I also climbed into the engine compartment checking everything that could leak and came out with some minor burns but no leaks. So now I am about out of my patience and not really happy because its late valve timing. What exactly is late valve timing and how is it fixed? I think I have an Idea but I dont know if its correct.
"May the sun shine in your face and the sparks fly far behind you"


 
SuperSport 
Super Senior Member
Posts: 6501

Reg: 07-03-01
02-09-09 08:07 PM - Post#1626531    
    In response to CaptainStompAndSteer

I know you said you re-adjusted the valves... What method did you use?

Late valve timing would be a loose timing chain or the chain installed 'off the marks' or retarded by using the wrong keyway on the bottom gear (if the gear has three keyways).
~SS~


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-09-09 08:34 PM - Post#1626549    
    In response to SuperSport

I did it while the motor was running. I backed the nut off until it clicked loud and tightened it back up just until it was quiet. My father in law told me something about a timing chain set I cant remember the brand off hand that when they are dot to dot they are actually something like 6 degrees retarded. So if that is true I might possibly have it retarded a few degrees. He is going to come over tomorrow and check it out for me.
"May the sun shine in your face and the sparks fly far behind you"


 
bobb 
Super Senior Member
Posts: 4936
bobb
Loc: paradise
Reg: 09-05-03
02-09-09 08:37 PM - Post#1626555    
    In response to CaptainStompAndSteer

if thats what it is then your cam needs to be dialed in.....no fun.
70 L camino 350 all forged,174 baby blower, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
SuperSport 
Super Senior Member
Posts: 6501

Reg: 07-03-01
02-09-09 09:31 PM - Post#1626609    
    In response to bobb

I think dot to dot is straight up (stock position), but the gear with three keyways has a dot, triangle, and maybe a square or other symbol for an advance or retard installation.

If you installed the bottom gear onto the triangle keyway, then lined up dot to dot, the valve timing is off.
~SS~


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-10-09 09:47 AM - Post#1626922    
    In response to SuperSport

My timing set wasnt the adjustable type. I set it or thought I set it up dot to dot. I guess its possible it could be off because of some type of installation error. How much would you advance a cam anyway?
"May the sun shine in your face and the sparks fly far behind you"


 
Trucked_up 
Valued Contributor
Posts: 4946

Loc: 315 er
Reg: 03-23-02
02-10-09 10:03 AM - Post#1626934    
    In response to CaptainStompAndSteer

Getting the cam timing off a few degrees by using the wrong keyway on a triple keyway gear will move the power band up or down a couple of hundred RPM's.The engine might be a little doggy but I don't think it'll give what you describe.
Some cams have advance built into them,some don't,check your cam card specs.
Maybe start from the beginning with a degree wheel and dial indicator and check the cam timing before you go any furthur.
If it's a brand new engine all this poor running won't do any good for ring seal.


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-10-09 04:30 PM - Post#1627223    
    In response to Trucked_up

I have help coming over later tonight. If its not the cam what would you look into next?
"May the sun shine in your face and the sparks fly far behind you"


 
bobb 
Super Senior Member
Posts: 4936
bobb
Loc: paradise
Reg: 09-05-03
02-10-09 07:11 PM - Post#1627388    
    In response to CaptainStompAndSteer

im thinkin we need to take a step back before we tear down the whole engine for nthing. hows about full specs on this new engine? is there any remote chance there could somehow possibly be solid lifters in it? if its unknown you can adjust all the valves till they click when running and see how it runs. hell after you do one head it would run better or not.
70 L camino 350 all forged,174 baby blower, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-10-09 07:31 PM - Post#1627407    
    In response to bobb

My father in law took a look at it and seems to think the cam might need to be advanced and also noticed how it seems to pick up a miss fire under load. He thinks the main problem has to do with the secondary ignition system. I will start with checking plugs and then probably swap out the distributor and see what happens from there. He brought over his Ferret timing light and ignition was spot on.

The motor is a 355 about 10:1 comp ratio. Forged Mahle flat top pistons. Stock crank .020 undersized stock rods resized and fitted with ARP bolts. 487 casting heads milled to the max with 2.02/1.60 valves major port work done enlarged springs guide plates etc. The cam is a comp cams magnum 292 .501 hydraulic flat tappet. Intake manifold is a victor jr port matched to heads. Exhaust is running through a set of Doug Thorley Tri Ys with 2 1/2 inch collectors to dual 2 1/2 inch pipes with 40 series flow masters. Typical cheapo street thrasher.
"May the sun shine in your face and the sparks fly far behind you"


Edited by CaptainStompAndSteer on 02-10-09 07:46 PM. Reason for edit: No reason given.

 
Greggy 
Senior Member
Posts: 541
Greggy
Loc: Perth, Western Australia
Reg: 05-22-03
02-11-09 03:41 AM - Post#1627576    
    In response to CaptainStompAndSteer

So you have a 10:1 355 SBC with a Comp Magnum 292 camshaft and a Victor Jnr (single plane 3500-8000rpm) intake manifold and you are wondering where your idle vacuum has gone? That combination is basically not going to make much idle vacuum at all!

Even my 9.7:1 383 SBC with a Comp XE274 cam and Weiand Stealth 8150 (dual plane) manifold barely makes 11-12" Hg during it's lopey idle (thats with initial timing at 12 degrees BTDC) so your idle vacuum is going to be below 10" Hg for sure which will equate to very poor idle quality.

Also, if you're running a Holley style carb with a stock Power Valve your possibly going to run into even more trouble as you'll be in PV-idle opening territory with that (small) amount of vacum, and the idle quality will get even worse with the overly rich condition caused by the PV being open during idle.

Ditch the Victor Jnr intake for a Performer RPM Air Gap and things will get better.

Regards,

Greggy - 1963 Impala 383 PG

 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-11-09 07:56 AM - Post#1627722    
    In response to Greggy

The carb is actually an Eddy performer. I just figured I would get a little more vac at idle at least 12-14. Other than it not wanting to idle and droping a hole under load it is still quite street able and if I smash the gas it will blister the tires even with the 12 inch wide tires under the back effortlessly. I just want the truck to run the way it should with this combo of parts if Idle in gear is crap then I guess thats the way it will be, I dont drive the truck because I have too its a toy that I can take on little cruises here and there and take to the strip on the weekends when I want. Now I just have to figure out why I am missing a hole under load.
"May the sun shine in your face and the sparks fly far behind you"


 
bobb 
Super Senior Member
Posts: 4936
bobb
Loc: paradise
Reg: 09-05-03
02-11-09 08:32 PM - Post#1628264    
    In response to CaptainStompAndSteer

i give up what is your torque convertor stall speed?
70 L camino 350 all forged,174 baby blower, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-11-09 08:36 PM - Post#1628270    
    In response to bobb

2500 roughly... I know it should be a little higher.
"May the sun shine in your face and the sparks fly far behind you"


 
bobb 
Super Senior Member
Posts: 4936
bobb
Loc: paradise
Reg: 09-05-03
02-11-09 09:06 PM - Post#1628293    
    In response to CaptainStompAndSteer

whats your timing advance curve like?
70 L camino 350 all forged,174 baby blower, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-11-09 09:09 PM - Post#1628296    
    In response to bobb

12* inital 34 total at about 2700 RPM Give or take a little.
"May the sun shine in your face and the sparks fly far behind you"


 
CaptainStompAndSteer 
Junior Contributor
Posts: 451
CaptainStompAndSteer
Age: 32
Loc: Redding Ca
Reg: 01-29-08
02-13-09 01:50 PM - Post#1629338    
    In response to CaptainStompAndSteer

I have made a big improvement. I starting going through my spark plugs one at a time checking them for any obvious problems like cracks, boots not on all the way and gap. The last plug I pulled broke when I cracked it loose and I noticed that the plug was really wet. I replaced it and it runs 100% better. I dont think its totally dialed in yet but it idles in gear sounds like a prostocker but at least it was a step in the right direction.
"May the sun shine in your face and the sparks fly far behind you"


 
Greggy 
Senior Member
Posts: 541
Greggy
Loc: Perth, Western Australia
Reg: 05-22-03
02-13-09 04:52 PM - Post#1629455    
    In response to CaptainStompAndSteer

Well done! The simple things like a dodgy spark plug make a world of difference once you solve it.

Yeah I bet she idles like a popcorn maker... the CC XE274 cam in my 383 is fairly lopey, your Magnum 292 would sound fantastic!

Greggy - 1963 Impala 383 PG

 
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