Re: Befuddled with engine problem
 

As far as the smoke goes, a non-firing plug can allow the oil that splashes of the piston to accumulate in that cylinder. Just keep an eye on that plug (listen for a misfire) and wait to see if the smoke clears up. It can take a while. The plug could oil up a time or two before the rings get a good seat after not having fire in that hole for some time.

Re: Befuddled with engine problem
 

Well, first and foremost thank you all for your comments and guidance. I got back to work on the truck this morning and after last week adventures; I decided to go over the valves again just to be sure.

After the engine warmed up I pulled the right valve cover and found #4 intake with no movement at all. Great oil pressure coming up from the push rod - but no movement. I attempted to re-adjust but it completely bottomed out with no change except to drag down the idle.

It would appear that my worst fears are confirmed and the cam is wiped or best case a bent push rod. It's interesting that last week #6 - both intake and exhaust were inoperative. After adjusting they seem fine.

Thoughts - time to pull the cam?

(I took a short video but don't know how to up load it)

Re: Befuddled with engine problem
 

Push rod and rocker arm are in great shape. So stuck valve or wiped cam 😑

Re: Befuddled with engine problem
 

From everything you’ve described thus far, the only thing left to do is to pull the rocker on that number 4 intake and make sure the pushrod looks OK. The fact oil is coming through the pushrod to the rocker arm tells me the pushrod is seated In the lifter. If the pushrod is OK that lifter and camshaft are done. Because that cam lobe is sawed off The engine is now full of metal and all of the bearings are full of it too. By the time you spend the money to fix all these problems you still have an engine of unknown quality and a flat tappet cam. You can go through all the hoops for the repair and still face the same issue of wiping out another camshaft. In this situation I advise a customer to buy a warranteed $2000 GM brand new roller cam 350, spend the additional $500 in parts to convert as necessary and be done with it.

Steve weim55 Colorado

Re: Befuddled with engine problem
 

Steve - Push rod and rocker are good. I agree with you on the replacement engine. Any recommendations? If I’m gonna do this I would like something that has decent drivability but a great sound / cam as well.

Re: Befuddled with engine problem
 

Sorry to hear Jake. You're at a decision point - replacement 350 or LS conversion. I personally like GM's L31R as a good option - some good threads here -
http://67-72chevytrucks.com/vboard/s...d.php?t=764005
http://67-72chevytrucks.com/vboard/s...d.php?t=777296

There's always the basic GM Gen 1 Crate replacement, but it usually benefits from a little cam swappin. https://www.gmperformancemotor.com/parts/12681429.html
Similar, but 290 hp https://www.gmperformancemotor.com/parts/19355658.html

with vortec heads https://www.gmperformancemotor.com/parts/12681430.html

My favorite is the HT383, but it's not inexpensive. Stock L31R, or even one with a few minor upgrades is the best bang for the buck.
https://www.gmperformancemotor.com/parts/19355720.html

Recommend do research on GM sites, but always check out the price at Summit Racing or some of the dealerships around the country for much, much better deals. (recommend Radley Chevrolet, just google, you'll find it)
Disregard, found it! Here you go - you can either buy direct from them or on ebay, I've not found prices as consistently low as theirs yet. https://www.ebay.com/sch/m.html?_ssn...31&_sacat=6000 (once you get there, search for L31 in their store - or crate engs, etc)

Re: Befuddled with engine problem
 

Jeg’s has a smokin’ Deal on the L31 right now.
https://www.jegs.com/i/JEGS/059/0282/10002/-1

Re: Befuddled with engine problem
 

That is a very good deal on an L31. Wow. One note to keep in mind for those shopping, L31 has 2 bolt mains, L31R has 4 bolt mains. Not that important for our trucks, but a data point for consideration if you're planning to build a hot rod.

Re: Befuddled with engine problem
 

That is a good price. Not sure I’m actually building a hot rod but would like an engine with a decent sound. Not gonna race by any means but more show (sound) than go.

A burn out now and then would be cool too 👀

Re: Befuddled with engine problem
 

Going the L31 route is a good one I've done a couple times myself. You do have to change a few things: Flexplate, intake manifold, add an electric fuel pump, harmonic balancer and timing cover. There's couple threads on board with details of the swap. Likely the warranty is void if you swap cams. You may even find a good deal on a roller long block in the aftermarket with a cam you desire ready to go. While the stock L31 isn't a tire burner it is a great runner with excellent off idle and mid range. Much much stronger than a stock 350 that came in these trucks.

Steve weim55 Colorado

Re: Befuddled with engine problem
 

Between an L31 and an L31R, your sound will just come down to muffler choice - in which case I'd go with that great Jeg's price and be happy with the L31. Throw some cherry bombs behind it and grin til your teeth fall out :D

Re: Befuddled with engine problem
 

Before you drop $3000+ on a new engine, I have to ask.... Do you earn your living with this truck, or is it just a weekend cruiser? If the former, and money is no object, then I agree - a new engine is ideal. But if you drive it on weekends for fun, I'd sure be tempted to spend $200 on a cam and lifters (maybe $260 with a timing set) and see if I can have fun with the truck for another season or two. True, this engine's best days are probably behind you, but I'd be inclined to see how well it does with a fresh cam, especially for the relatively low cost.

Jon

Re: Befuddled with engine problem
 

Be careful tossing the phrase heat soak around since it can't happen to a cold engine, there's nothing stated to suggest it's happening hear, and in my (and many others) opinion, is a myth. Fix the wiring, charging system, timing and charge the battery.

Re: Befuddled with engine problem
 

I agree with you - I don't earn my living with it and its a weekend cruiser.

However, buyer beware is certainly the lesson of the day. Having recently purchased this truck I have been working on the drivability issues first. Unfortunately discovering both deeper and wider issues which are mostly poor work by the previous owner and being misled a good bit.

Don't get me wrong, this is a 52 year old truck and has great bones worth the work. Some of the issues would not have been found on initial impression and test drive.

With that said, this may well be my last opportunity to build a truck that fulfills my needs and dreams. So I am going with a new / remanufactured engine that has good drivability and power to play with. I'm going to pull the TH350 and go through it as well.

Once the new engine is up and running, I'll disassemble the current and perform an autopsy....🤔

Re: Befuddled with engine problem
 

If I had the money I would go ahead and get the L31. It's a great deal and you never have to worry about a wiped cam again.

Re: Befuddled with engine problem
 

I would go through the engine replace cam and lifters if oil pressure and compression was good on all 8 cylinders
check the valve springs clearance if the springs bind from to big a cam it will wipe a new cam quickly
https://www.hotrod.com/articles/how-...rance-is-safe/

To be even more sure do a complete tear down and rebuild the engine you have
an Engine rebuilder shop can measure your heads for valve bind and tell you how big a cam you can run as most of us do not own the tools to properly measure them

Before i spent 3 K on a new motor i would look more seriously into finding a late model truck for a donor engine and tranny for a better daily driver fuel economy if junk yard motor take everything complete wiring to complete acc rad gas pedal obdII plug etc all the little things turn this from a 1500 dollar swap to a 3 k plus swap
the old 3 speed auto and 4 speed sticks suck on the interstate compared to new auto or 6 speed stick

http://67-72chevytrucks.com/vboard/s...d.php?t=377348

This guy is a big help for the harness Diy and can reprogram your ecm
http://www.lt1swap.com/wiringharness.htm

Re: Befuddled with engine problem
 

Here is a link to a short video of the valve train and #4 intake not moving. This is taken after I tried to adjust it...

https://youtu.be/3zUJjUrnHYs

Re: Befuddled with engine problem
 

Update on the engine issues. I decided it was too much of a risk to just replace the cam and associated parts and hope for the best. This just seems like throwing good money after bad and a band aid fix that will eventually destroy the engine.

So I am pulling this engine a going with a re-manufactured. Not 100% sure but leaning toward the ATK mid dress from Summit. This will provide ease of replacement, dyno testing and a warranty. I am also changing out the torque converter to a B&M 2400 stall.

I pulled the front clip (super easy) and will rebuild the front suspension while I'm at it along with a new adjustable steering column.

This truck lived most of its life in New Mexico so its got great bones and I'm impressed with the lack of rust... Oh - by the way - it sucks working on a gravel pad...

Re: Befuddled with engine problem
 

Wise Choices, Boy do I know about the Gravel Pad thing. Grab a $%#*Load of cardboard boxes from work or a retail store. Fold em down and stack 4 on top of each other for some help with the back and the knees.

They soak up those oil spills also!

Re: Befuddled with engine problem
 

Great idea on the card board boxes! I'm sure I can recycle all the parts boxes about to arrive as well...

Re: Befuddled with engine problem
 

To prevent a cam wipe follow mfg specs on break-in.It's like 2000-2500 for the first 20 min. Then some increases and decreases in RPM. It's all there in the new cam instructions. And use a ZDDP additive during the break-in and from then on. Or,I use Valvoline VR 10-30 all the time and it has the ZDDP. Got mine from Amazon. Also change the oil after the initial break-in procedure and then again in 500 miles. I am very happy w/the Lunati 10120701LK cam. not radical but w/a little more lift then stock,good idle and good vac and good power boost.Comes w/new lifters for 180.00,Summit.

Re: Befuddled with engine problem
 

So out with the old...

Now to pressure wash and repair any hidden items under the grease and dirt. Replace the ball joints, front coil springs and any other bad bushings before the new engine is installed and front clip goes back on...

Re: Befuddled with engine problem
 

You've already got disc brakes that's a plus. The fun parts going to be trying to pull the motor while the cherry pickers stuck in the dirt. Been there done that. A piece of 1" plywood is your friend.

Re: Befuddled with engine problem
 

Indeed - The Kubota L3301 made it easy coming out by myself - will have help going back in... But the plywood most certainly makes it much more comfortable when working on your back.

Re: Befuddled with engine problem
 

The Kubota's cheating, or I guess I'm just jealous.