Could use some help Problem adjusting valves

[Danvitt]

Hello all, I have a new crate engine that I installed and I'm having a little trouble getting it to run smooth.

First off, I followed the instructions per the Haynes manual to adjust the valves (engine off procedure). Lightly using finger tips to turn push rod until resistance is felt, then tighten 3/4 of a turn.

Well first it started up fine and i ran it for a minute. Did this a few times (still had to bolt on the exhaust). I tried again later after I finished bolting up the pipes and it ran like crap. Noticed smoke and pressure coming through the TBI. So I backed off each of the intake rockers a 1/4 turn and it started running smoother. So then I proceeded to perform the adjustment with the engine running and found I had to back it way off. I loosened them up till the ticking noise is heard and tightened them up 3/4 a turn.

Here's the question. I've done extensive internet searching and everyone has a different variation of how many turns I should tighten. I've seen anywhere for 1/8 turn to 1 full turn (engine running procedure). Can you clear this up for me? This is a 93 5.7L chevy silverado.


Thanks for your help.

[MT-2500]

Originally Posted by Danvitt

Hello all, I have a new crate engine that I installed and I'm having a little trouble getting it to run smooth.

First off, I followed the instructions per the Haynes manual to adjust the valves (engine off procedure). Lightly using finger tips to turn push rod until resistance is felt, then tighten 3/4 of a turn.

Well first it started up fine and i ran it for a minute. Did this a few times (still had to bolt on the exhaust). I tried again later after I finished bolting up the pipes and it ran like crap. Noticed smoke and pressure coming through the TBI. So I backed off each of the intake rockers a 1/4 turn and it started running smoother. So then I proceeded to perform the adjustment with the engine running and found I had to back it way off. I loosened them up till the ticking noise is heard and tightened them up 3/4 a turn.

Here's the question. I've done extensive internet searching and everyone has a different variation of how many turns I should tighten. I've seen anywhere for 1/8 turn to 1 full turn (engine running procedure). Can you clear this up for me? This is a 93 5.7L chevy silverado.


Thanks for your help.

Depends on what the full travel of lifter is.

Factory specs = center the lifter for adjustment.
Like.
If a 3 turn lifter set adjustment in center of lifter or 1-1/2 turns.

I always adjust them on looser side like 3 turn lifter set at 1 turn.

I like to set them good engine off and forget the messey engine running. seetting.

Most good crate engines should already be adjusted.

[Danvitt]

Thanks for your response.

I think the engine off procedure should be left to you professionals (having the intake not seating allowing gases to come up through the TBI is proof). For the rest of us who only do it once or twice a lifetime the messy engines a little more fool proof which is exactly what I need. With a little side benefit of rust protecting my fenders

That makes sense about the lifter travel and why I'm getting so many different answers. Since this is a stock motor their must be some kind of constant though. I'm not sure how I can determine what type of lifters I have. I think I'll try backing it off another 1/4. That will leave me with a half turn after the clicking disappears.

[j cAT]

Originally Posted by Danvitt

Thanks for your response.

I think the engine off procedure should be left to you professionals (having the intake not seating allowing gases to come up through the TBI is proof). For the rest of us who only do it once or twice a lifetime the messy engines a little more fool proof which is exactly what I need. With a little side benefit of rust protecting my fenders

That makes sense about the lifter travel and why I'm getting so many different answers. Since this is a stock motor their must be some kind of constant though. I'm not sure how I can determine what type of lifters I have. I think I'll try backing it off another 1/4. That will leave me with a half turn after the clicking disappears.

I did this long ago . the proceedure with engine off is more involved. try the proceedure below . post back what / how it worked out.

Remove the valve cover.


Install the oil deflectors over the tube and around the rocker end.




Start your engine and check for excessive oil spurting onto the ground or other engine parts.




Slowly turn the rocker arm nut counterclockwise until you begin to hear a tapping sound. Slowly turn it clockwise, a quarter turn at a time, waiting 10 seconds between turns to allow the engine to compensate for the new adjustment. Stop when the nut has been turned a total of one full revolution.

• 5 Adjust the other valves one at a time until one side of the engine is finished. Shut the engine off, reinstall the original valve cover, and repeat the procedure on the other side.
  
  

[Danvitt]

I'll try that, Just afraid of tightening it to much and getting the piston to valve contact I had in an earlier post. Right now its sitting at a quarter turn.

It has smoothed out quite a bit but I have rough and erratic idle. It stalls after it runs for awhile. I noticed when I disconnect and plug the vac line of the imap sensor it has a real smooth idle until I throw it in gear. I’m at a loss at what to do next. I’m not sure adjusting the valves is still an issue.


Maybe I shorted something out when I was installing the engine. I did turn the key on with wires laying everywhere I was priming the oil pump. I did that because the only oil pressure gauge I had is in the dash. If you have thoughts on what to check for please post them. As it was, the engine was running better when I had a blown head gasket.

[j cAT]

Originally Posted by Danvitt

I'll try that, Just afraid of tightening it to much and getting the piston to valve contact I had in an earlier post. Right now its sitting at a quarter turn.

It has smoothed out quite a bit but I have rough and erratic idle. It stalls after it runs for awhile. I noticed when I disconnect and plug the vac line of the imap sensor it has a real smooth idle until I throw it in gear. I’m at a loss at what to do next. I’m not sure adjusting the valves is still an issue.


Maybe I shorted something out when I was installing the engine. I did turn the key on with wires laying everywhere I was priming the oil pump. I did that because the only oil pressure gauge I had is in the dash. If you have thoughts on what to check for please post them. As it was, the engine was running better when I had a blown head gasket.

put a vacuum guage on the engine. see how the vacuum guage reads/needle moves. this tells much about how the valves are working..

with a solid steady needle you know the valves are correct..

17-21 inches steady is normal at idle.

the 1 full turn is possibly a bit high. most find 3/4 turn..the lifters may be sticking throwing off this..rebuilt engines do have some dirt in them , which can get into the lifters, causes this to be a pita...do the adjustment with a warm engine ..


use the vacuum guage to see if the exhaust is plugged...remove the upstream O2 sensor see if the back pressure is the issue.

[Danvitt]

My problems are solved. It appears that all i needed to do get to run smooth was take it for a drive. Thanks to all who took the time out to give a response.

For those who might read this thread looking for info how to adjust valves be very careful with the engine off procedure. I ended up doing mine 4 times trying to get it right (and it still wasn't). I would spin the pushrod until it stops, then tighten 3/4 turns. As I hand turned the engine I felt it stop. This was dreaded piston to valve contact. I had to back everything off quite a bit and start over. This procedure is very subjective and takes quite a bit of experience in my opinion. In any case, make sure you hand turn the engine twice (2 full revolutions) before you attempt to start it. This will tell you if there is a problem.

I'm still not sure how many turns the valves should be tightend. However, if my thinking is right, it shouldn't matter if I went light. It just dictates how soon I will have to readjust.