Engine trouble - The 1947 - Present Chevrolet & GMC Truck Message Board Network

psmall000 · 04-20-2009, 10:45 AM

Hi guys, new here. I have a '69 LW with a 350 bored .060, flat top pistons,truck heads and a mild cam. I can't seem to get it running. The issue is when I turn it over it coughs and sputters and won't stay running. I have timed it 3 or 4 times and I am 90% sure its timed correctly. The last time it ran before I gave up, it bent pushrods and pitted brand new lifters. I thought maybe it was 1) Accidentally built too much compression in the engine and not enough octane, or 2) the rocker arms are the wrong ratio. I know it's not the valve adjustment, that is set to factory specs (according to Haynes).

**WorkinLonghorn** · 04-20-2009, 11:22 AM

Sounds like the timing chain is off a few teeth. Either that or like you said,the rockers are 1.6 and there is piston-to-valve contact which bent some valves and now it won't run because of all the leaking valves.
You need to check what rockers those are, stock was 1.5-1. Then if you have the right rockers check the compression on all cyliners.If you have the wrong ones, change them first.
If you have the right rockers and have compression then I'd check to see if the timing chain is set right. If you know the cam specs and have a degree tape on the balancer you can check it this way,or you just take the timing cover off and look at the marks on the sprockets.

psmall000 · 04-20-2009, 11:36 AM

Hmmmm, last time I tried compression testing I couldn't hold the tester on the hole (it blew me off). I don't have a screw-in tester, I have the old style press and hold type (pain in the butt). I don;t know if I just wasn't holding it on good enough or if it really was that strong. According to everything I know, my set up should produce about 9.5:1 - 10:1 ratio.

cdowns · 04-20-2009, 11:54 AM

square one in timing an engine is to manually with aid of piston stop place the engine at TDC on the COMPRESSION STROKE for the number one cylinder then you can see if your balancer marks and timing pointer line up

psmall000 · 04-20-2009, 12:04 PM

Yeah, um they don't. I knew that to begin with. I can't find a decent balancer that isn't spun a little, and I can't afford a new one. I can work around that, however, at least for a while. Also, I have the heads installed so even if I had a piston stop, I couldn't use it. I used the old fashioned method of making sure both valves are closed then watching the piston thru the spark plug hole. That's how I found out my balancer is spun.

dznucks · 04-20-2009, 01:35 PM

a piston stop is less than $10 and it screws into the spark plug hole. even if your balancer has spun you can make a new mark pretty accurate with one.

psmall000 · 04-20-2009, 01:54 PM

Good to know

I didn't realize there was a plug hole type.

PanelDeland · 04-20-2009, 07:57 PM

Quick question.Does then engine actually start then die when the key is released?If so it may be the ignition wire with the fuseable link is bad.

I always look for the simplest solution first,so if you have checked this disreguard.

psmall000 · 04-20-2009, 10:09 PM

No, Its not an ignition problem I already ruled that out. Its either a timing issue or a combustion issue. Possibly a valve train issue.

psmall000 · 04-21-2009, 01:34 PM

Once I verify that the timing chain is in the correct position, if it turns out to not be the problem, what would that narrow down to?

psmall000 · 04-21-2009, 04:06 PM

I just found out from a guy that its possible that when the shop rebuilt my heads, they didn't ream out the new valve guides. He said that if the valves are too tight you will bend rods and the engine won't run.

04-20-2009, 10:45 AM	#1
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Engine trouble Hi guys, new here. I have a '69 LW with a 350 bored .060, flat top pistons,truck heads and a mild cam. I can't seem to get it running. The issue is when I turn it over it coughs and sputters and won't stay running. I have timed it 3 or 4 times and I am 90% sure its timed correctly. The last time it ran before I gave up, it bent pushrods and pitted brand new lifters. I thought maybe it was 1) Accidentally built too much compression in the engine and not enough octane, or 2) the rocker arms are the wrong ratio. I know it's not the valve adjustment, that is set to factory specs (according to Haynes).

04-20-2009, 11:22 AM	#2
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,886	Re: Engine trouble Sounds like the timing chain is off a few teeth. Either that or like you said,the rockers are 1.6 and there is piston-to-valve contact which bent some valves and now it won't run because of all the leaking valves. You need to check what rockers those are, stock was 1.5-1. Then if you have the right rockers check the compression on all cyliners.If you have the wrong ones, change them first. If you have the right rockers and have compression then I'd check to see if the timing chain is set right. If you know the cam specs and have a degree tape on the balancer you can check it this way,or you just take the timing cover off and look at the marks on the sprockets. __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme.

04-20-2009, 11:36 AM	#3
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Re: Engine trouble Hmmmm, last time I tried compression testing I couldn't hold the tester on the hole (it blew me off). I don't have a screw-in tester, I have the old style press and hold type (pain in the butt). I don;t know if I just wasn't holding it on good enough or if it really was that strong. According to everything I know, my set up should produce about 9.5:1 - 10:1 ratio.

04-20-2009, 11:54 AM	#4
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Engine trouble square one in timing an engine is to manually with aid of piston stop place the engine at TDC on the COMPRESSION STROKE for the number one cylinder then you can see if your balancer marks and timing pointer line up __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

04-20-2009, 12:04 PM	#5
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Re: Engine trouble Yeah, um they don't. I knew that to begin with. I can't find a decent balancer that isn't spun a little, and I can't afford a new one. I can work around that, however, at least for a while. Also, I have the heads installed so even if I had a piston stop, I couldn't use it. I used the old fashioned method of making sure both valves are closed then watching the piston thru the spark plug hole. That's how I found out my balancer is spun.

04-20-2009, 01:35 PM	#6
dznucks Registered User Join Date: Feb 2006 Location: Smyrna, Ga Posts: 1,647	Re: Engine trouble a piston stop is less than $10 and it screws into the spark plug hole. even if your balancer has spun you can make a new mark pretty accurate with one.

04-20-2009, 01:54 PM	#7
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Re: Engine trouble Good to know I didn't realize there was a plug hole type.

04-20-2009, 07:57 PM	#8
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: Engine trouble Quick question.Does then engine actually start then die when the key is released?If so it may be the ignition wire with the fuseable link is bad. I always look for the simplest solution first,so if you have checked this disreguard. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil" Last edited by PanelDeland; 04-20-2009 at 07:58 PM.

04-20-2009, 10:09 PM	#9
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Re: Engine trouble No, Its not an ignition problem I already ruled that out. Its either a timing issue or a combustion issue. Possibly a valve train issue.

04-21-2009, 01:34 PM	#10
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Re: Engine trouble Once I verify that the timing chain is in the correct position, if it turns out to not be the problem, what would that narrow down to?

04-21-2009, 04:06 PM	#11
psmall000 Registered User Join Date: Apr 2009 Location: Booneville, Ar. Posts: 39	Re: Engine trouble I just found out from a guy that its possible that when the shop rebuilt my heads, they didn't ream out the new valve guides. He said that if the valves are too tight you will bend rods and the engine won't run.



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