TBI rebuild

[Schurkey]

1. You have a hydraulic cam. You don't have "valve lash", you have "lifter plunger preload", or "Lifter preload".

2. With compression numbers like you're getting, I don't know how the lifter preload could be too tight.

OTOH, checking preload is simple; although a bit messy if the engine is running. Used to be a guy could cut the top off of a scrap (perimeter-bolt) valve cover, and use that to hold the oil in. But since Chevy switched to four bolts along the top of the cover, cutting the valve cover got a lot harder.

 

[tsr2185]

1. You have a hydraulic cam. You don't have "valve lash", you have "lifter plunger preload", or "Lifter preload".

2. With compression numbers like you're getting, I don't know how the lifter preload could be too tight.

OTOH, checking preload is simple; although a bit messy if the engine is running. Used to be a guy could cut the top off of a scrap (perimeter-bolt) valve cover, and use that to hold the oil in. But since Chevy switched to four bolts along the top of the cover, cutting the valve cover got a lot harder.

Correction*** I will check my lifter plunge preload tuesday when my oil deflector clips from autozone come in, thanks schurkey.

https://www.autozone.com/engine/rocker-arm-clip/p/mr-gasket-rocker-arm-clip-8-piece/782151_0_0

I agree (with my limited knowledge), that my compression numbers indicate I have no pre-load issues, but what the heck why not? Unless cylinder 8 is too tight (highest was 175psi, cyclinder 8 was 158psi)

 

[tsr2185]

1. You have a hydraulic cam. You don't have "valve lash", you have "lifter plunger preload", or "Lifter preload".

2. With compression numbers like you're getting, I don't know how the lifter preload could be too tight.

OTOH, checking preload is simple; although a bit messy if the engine is running. Used to be a guy could cut the top off of a scrap (perimeter-bolt) valve cover, and use that to hold the oil in. But since Chevy switched to four bolts along the top of the cover, cutting the valve cover got a lot harder.

Do you suggest I get valve cover gaskets ordered before I do this? Who knows w
What shape those gaskets are in I assume. Are they normally reusable, or do they fall apart like the tbi gaskets?

 

[Schurkey]

Any of the "center bolt" valve cover gaskets, including TBI, seem to be very durable, and re-usable.

I'd wait until I knew for sure that yours were bad before buying replacements.

 

[tsr2185]

Any of the "center bolt" valve cover gaskets, including TBI, seem to be very durable, and re-usable.

I'd wait until I knew for sure that yours were bad before buying replacements.

Thanks for input

I def need to change both valve cover grommets, they both hard and a little cracked

 

[tsr2185]

1. You have a hydraulic cam. You don't have "valve lash", you have "lifter plunger preload", or "Lifter preload".

2. With compression numbers like you're getting, I don't know how the lifter preload could be too tight.

OTOH, checking preload is simple; although a bit messy if the engine is running. Used to be a guy could cut the top off of a scrap (perimeter-bolt) valve cover, and use that to hold the oil in. But since Chevy switched to four bolts along the top of the cover, cutting the valve cover got a lot harder.

Well checked preload and a lot of the valves were much tighter that 1/4 past lash. Still changed nothing.....

 

[tsr2185]

yes, back out the min idle screw at little at a time.

Once you get those adjusted you should drive around a while, and get more samples, to see if your BLM normalizes out more. Right now you're running a little lean in higher MAP samples. INT (short term fueling) and BLM (long term fueling) s/b ~128 for 14.7 AFR stoich.

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I'll get another log going tomorrow. Checked my lash and no change whatsoever. They were way more than 1/4 past, but I also noticed the oil just trickling out the rockers. Definitely no spraying. I do have a quart of lucas oil with conventional 10w30 in it, I'm thinking of changing the oil again after 2kmiles just for the helluva it. Also wondering if pulling my fuel sending unit and checking bottom of tank and sock may be a good idea?

 

[thinger2]

Looking at my grounds closer with better light, I reterminated the 4 wires on the thermostat housing. What circuits do those 4 wires ground? They were in rough shape. I also am going get my firewall to frame ground stap tomorrow. That one was broke and hanging, didnt know about that one.

Do the passenger side back of the head to firewall and from firewall to frame ground.
Often overlooked and kind of a ***** to get at but it is very important

 

[tsr2185]

Do the passenger side back of the head to firewall and from firewall to frame ground.
Often overlooked and kind of a ***** to get at but it is very important

I changed the firewall to frame with a 6 guage battery cable ( all autozone had) cause it was broke. I can get another and change the back of head to firewall also (still intact but in rough shape)

What's the symptoms if the firewall to head strap is bad?

https://www.autozone.com/batteries-starting-and-charging/battery-cable-and-lug/p/duralast-6-gauge-lawn-and-garden-switch-starter-cable/95947_0_0?cmpid=LIA:US:EN:AD:NL:1000000:BAC:71700000060662128&gclid=EAIaIQobChMI-4yv-v628gIVD21vBB3QvAfXEAQYASABEgKgufD_BwE&gclsrc=aw.ds

 

[thinger2]

Dude I've damn near done everything.
Compression check
Base timing to 0
New IAC, egr, egr solenoid, CTS, dizzy, wires, plugs, IC, all new vac lines, vac test (-22), rebuilt TBI, fuel filter, fuel pressure test (11.5 psi)...

It didnt run when I bought it in dec, until I put the new spectra dizzy in. Been having rough idle since and nothing made a difference.

Got a ac delco ICM coming in to replace my spectra dizzy one (which is only 6 months old).

Playingwithtbi been helping me a ton. But it's hard to tell anything in the data stream (but I'm a NooB)

Did you do the reset/ relearn procedure when you replace the IAC?
Did you do it with the engine hot and at 0 TDC?
Are you sure that number 1 piston is at TDC no matter what the timing mark reads.
They slip. They are known for it.
Pull the plugs, find TDC without referencing the timing mark.
Was the thermostat open when you did that?
Are you absolutely sure beyond a doubt that the distributor is not off one tooth and are you sure that is seated correctly and not moving on you.
Start from scratch.
Do it one step at a time and check it off the list.
All of the basic geometrys and rotations and timing need to be correct.
And wiring and vacuum etc..
Then all of the basic relearn and reset procedures need to be done in the proper order.
I think you are chasing a very basic problem somewhere in that process.