Dreaded intake manifold leak...I think?

[stutaeng]

Thanks! It is the truck in my avatar, 97 K1500 I inherited from my grandpa who bought it new in 97. Got it a year and a half ago with 52k on it, bone stock. It spent most of its life in his garage as he had multiple vehicles. Now that it’s my DD, issues like this start to pop up (already replaced a few seals, fuel pump, coolant hoses, water pump, full ign tune-up, etc.) Luckily I am mechanically inclined and feel confident I can tackle the job. The truck runs beautifully otherwise.

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Nice!

The fuel lines and distributer removal and reinstallation is the hardest part. I did my '99 Silverado 4.3 last winter, and wasn't too bad. The 4.3 doesn't have adjustable timing, so it's a bit easier.

However, on the V8s I believe you need a scanner to adjust the distributer. Some 1,000RPM procedure. Not sure if you can mark the position and reinstall in the same orientation. I'm sure someone here knows if this is possible.

Advance Auto shows Fel-pro model no MS 98000 T for my '00 k3500 5.7 engine. Should be the same as yours.

 

[shorepatrol]

Mark your distributor and rotor before you take it out. You won't need to mess with timing if you get it to drop back exactly where it was

 

[454cid]

Mark your distributor and rotor before you take it out. You won't need to mess with timing if you get it to drop back exactly where it was

Dropping it in in exactly the same spot? The spec is +/-2 degrees... I think you'd have to be really good, or lucky to do that. You can probably drop it and have it run, and not set a code, but that's because the code doesn't get set until it's something like 20 degrees out. It's not really timing you're adjusting, it's the relationship between the cam and crank sensors... the PCM handles the timing.

 

[454cid]

However, on the V8s I believe you need a scanner to adjust the distributer. Some 1,000RPM procedure.

It's not hard to do, but you need a scanner that sees the right value. A lot of them don't. It's also handy to have a second person operating the ignition key. Once you loosen up the distributor, it won't stay in place with the engine running. I held the distributor in place once I got it were I wanted it, and had someone else shut the truck off. Then I was able to tighten the bolt. It might be easier on a 350. The 454 doesn't have much clearance back there.

To raise the RPM, I just wedged a small screwdriver in between the throttle cam, and throttle stop.

 

[shorepatrol]

Dropping it in in exactly the same spot? The spec is +/-2 degrees... I think you'd have to be really good, or lucky to do that. You can probably drop it and have it run, and not set a code, but that's because the code doesn't get set until it's something like 20 degrees out. It's not really timing you're adjusting, it's the relationship between the cam and crank sensors... the PCM handles the timing.

That's how I did mine. Took about 20 stabs to get it exactly lined up. No problems for 2 years now.

 

[jjupiter100]

That's how I did mine. Took about 20 stabs to get it exactly lined up. No problems for 2 years now.

Yep, 20 stabs (or more ) is about right

 

[1998crewcab]

If you mark rotor and distributor
I used a long metal ruler and made landmarks on the firewall etc.
When reinstalling I used land marks to put everything back as marked
Take pictures
Was off less than 1/2 degree
And fired right up

 

[1998crewcab]

You don’t have to be lucky
Just logical in disassembly and re-assembly
I cleaned out bolt holes and ran a chaser in them and cleaned them again with brake cleaner
Proper Torque is everything
I also installed new ARP intake bolts

 

[454cid]

Was off less than 1/2 degree
And fired right up

How do you know you were less than a 1/2 a degree off? My scanner won't tell me any less than a single degree.

It'll fire up even when way out. It won't even set a code until it's over 20 degrees out.

 

[east302]

How do you know you were less than a 1/2 a degree off? My scanner won't tell me any less than a single degree.

It'll fire up even when way out. It won't even set a code until it's over 20 degrees out.

What scanner were you using? I have a knock-off tech2 that only shows the CMP offset in degrees, no decimals. I was surprised to see that. I used the DashCommand app before and it had it to the tenths; I think CarGauge Pro had the same resolution.

GM’s spec was zero plus or minus two degrees, so I guess having a 1/10th accuracy really wasn’t that critical in their eyes?