jimbosprint 1972 C20 - the good, the bad, and the ugly

[jimbosprint]

Originally Posted by Oldtruckfanatic

Whats the casting number on that head. Maybe I have one.

Casting number is 3986339

I also notice the pushrod moves side to side a little in the slot through the cylinder head.

[jimbosprint]

I cleaned out the bed toolbox this morning. It's fairly mangled from the body damage, and it hadn't been opened in many years as far as I could tell. Found an unopened can of oil that was pretty much empty, and the oil was now a big puddle of black gook that was leaking out of the toolbox. There was also a tire iron and a box wrench in there.

[no1udknow]

Originally Posted by jimbosprint

Can of worms...

I just wanted to do a compression test, but I had a couple parts from LMC I just couldn't wait to put on like the decal for my freshly painted air cleaner. I also ordered new oil caps and for some stupid reason I decided to replace the one on the passenger valve cover. Turns out it was so old and dry that it broke into pieces that fell into the valve cover. I don't want that in the oil system, so now I have to take the valve cover off before I can start the engine again or do a compression test.

It's a bit of a pain because of the AC compressor, but I get the cover off and find a crispy black worthless gasket under it, along with this:



The second rocker from the front (right on photo) is loose and sits twisted off the side of the valve spring. I took it off and find the pushrod is bent and there is a really big gouge in the side of the stud where the rocker was cutting into it. The hole in the rocker is also worn out of shape a little. I thought there was a lifter making noise, but I believe this was the problem.



Now the tough decision - keep digging or pull the motor out? I really wish I had done that compression test, and I really wanted to drive it before taking it completely apart.

I have had some experience with this on my 73, the stud was messed up and started to come loose. My dad was looking at it with me and told me I had 2 options, either pull the head and take it down to have the stud welded in, or pull the stud, thread the hole, and use a threaded stud. The original studs are pressed into the hole and can be removed using a nut and a socket that fits over the stud, just tighten down the nut and heat the head at the base of the stud with a map gas torch and it will pull out. Then you can find replacement stud kits that come with a tap, you tap the hole, and thread in the new stud with some green loctite and voila... new stud. then you can get a new push rod pretty cheap at the local auto parts house.

[no1udknow]

on this page, the guy installs pushrod guides along with the threaded studs, a good way to avoid this happening again.

http://www.classictrucks.com/tech/13.../photo_15.html

[jimbosprint]

I decided to go ahead and pull the motor and transmission. I just don't think it's worth trying to fix the head or dig any deeper when I don't know the true condition of the motor. That, and that fact that I know it burns and leaks oil (this is easily the greasiest engine I have ever worked on).

I'm thinking about going with the GM 260hp crate engine, and put it back mostly stock except a Performer EPS manifold, Performer 600cfm carb, and HEI distributor.

Got it just about ready to remove - only exhaust, driveshaft, and motor mounts holding it in.

[no1udknow]

Jimbo, do you already have a carb? I have an extra edlebrock performer 600 im looking to sell (I hope it's not taboo to post that here, if so sorry admins)

[Xeen]

Just a thought here.
A lot of guys go with the 290 HP Deluxe and enjoy the hell out of it.
It is a very popular GM crate motor.
Here is a link so you can check it out.
http://www.chevrolet.com/performance...50-290-hp.html

[jimbosprint]

Originally Posted by Xeen

Just a thought here.
A lot of guys go with the 290 HP Deluxe and enjoy the hell out of it.
It is a very popular GM crate motor.
Here is a link so you can check it out.
http://www.chevrolet.com/performance...50-290-hp.html

Looks nice, but I can live without 30hp and with $550 extra in my pocket.

[jimbosprint]

I got a chance to talk to a previous owner of my truck today, the stepfather of the person I bought it from. He said his father got it used in the late 70s or early 80s and rarely used it as his health declined. And he also said that after he inherited it all he ever used it for was runs to the dump, and that it often sat for months without being started. He had no idea what the mileage was, but said it never had any major work, and only recently had a few things done to get it running for the stepson who needed something to drive a little over a year ago (carb rebuild, brake booster/master, radiator and hoses).

The current condition makes me think the stepson that owned and drove it for the last year didn't take especially good care of it, but that is why it has come to me. Still, I'm thinking I was lucky to get this truck that belonged mostly to one family and apparently wasn't used much since the 80s.

[jimbosprint]

Pulled the engine and transmission today!

[jimbosprint]

Power washed the engine to get the heaviest grease off. The motor is coming apart so I'm not too worried about the water, but I was careful and mostly got the sides and bottom. I was able to get to the engine code and casting numbers, but the VIN code is likely hiding behind the flywheel that I should have taken off before putting it on the stand. Everything matches so far.

Here's a few pics:

[jimbosprint]

Based on the photos I've posted here, what would you do? I still can't decide whether to rebuild or replace. (does anyone read my thread? )

With the problem in the one head, I figure it is going to be considerably more expensive to rebuild vs a crate engine. Local shop quotes for a basic rebuild are $1450-1900, while a crate 260HP is on my door for $1510.

I don't want a race car, and the truck is never going to be in a museum. I just want reliability along with a good balance of performance/efficiency. Should I care about "original engine"?

[Xeen]

Crate motor sounds like a good deal to me.

[jimbosprint]

Thanks Xeen.

I guess you have to build a race car, lowrider, or monster truck to get anyone on here to read your thread. I'm not interested in those things. I was just hoping to get advice from people who are experienced with '67-'72 Chevy trucks. /rant

[Pick]

Unless you can do most (almost all) of the work yourself and your block and heads don't require much in the way of machine work, you will come out cheaper going with the crate engine. Going by what I see so far, I'd opt for the crate engine.

[mcbassin]

Hard to beat a well built crate engine. If you're cheap ass like me, it's hard to beat craig's list too. I have gotten several smoking deals on motor/tranny combos. I search out wrecked trucks. Sometimes you can actually part out and scrap out the donor and make a few bucks. Plus if you can hear it run first that's great, or like my last one, I drove it up on to the trailer.

[Xeen]

Jimbo my build isn't super popular either but as time has gone on I have gotten more viewers and you will too.

[knomadd]

I just found your thread. I too would go with the crate engine. It always seems to be cheaper in the long run, especially if you have a lot of machining to do on the block and heads. You might look into it, but you may even get a warranty with a crate motor. I've had 30 and 90 day warranties from engine builds, but I believe I've seen (been too long) 1 year warranties or possibly longer on crate engines. Those might be fore complete turn key systems though.

[jimbosprint]

I just ordered the crate. Noticed is was on sale on Ebay. Too good a deal to pass up.

[Xeen]

Originally Posted by jimbosprint

I just ordered the crate. Noticed it was on sale on Ebay. Too good a deal to pass up.

Nice!

[flashed]

You wont be disappointed with the crate motor ,I have 2 of them and they are great .I put a 290 HP crate motor in my wife's 72 Malibu convertible and a 260 HP one in my 72 truck ,the 260 HP one would have been just fine in the Malibu too but it sure is fun.

[jimbosprint]

Just ordered some more parts for the new engine, including an Edelbrock Performer EPS intake, Edelbrock Performer 600cfm carb, and Summit HEI distributor.

I also got a Harbor Freight parts washer and have spent the last few days cleaning up parts. The bolts, brackets, and other parts that will be re-used all need to be de-greased and prepped for painting. It's a chore, but it will be worth it.

[jimbosprint]

Summit parts order arrived!

Edelbrock 1406 Performer carburetor
Edelbrock black air cleaner (FREE with carb)
Summit black air cleaner (that doesn't say Edelbrock on top in huge letters)
Summit HEI distributor
Summit harmonic balancer
Delco spark plugs
Fuel line from fuel pump (have to modify for the Edelbrock carb)

[BB72CHEVKT]

I think you made a wise decision on the crate. They are very reliable.

[jimbosprint]

Originally Posted by BB72CHEVKT

I think you made a wise decision on the crate. They are very reliable.

Thanks.

But maybe not so wise on the Summit air cleaner. It feels kinda flimsy and has sharp edges. I don't care for the "Edelbrock" writing on the top of the free one, but it is a much nicer air cleaner and I think it will go on the truck.