Replacing head gaskets & painting an engine

[71CHEVYSHORTBED402]

71 C-10, 402. For what it's worth, I'm green and have never pulled heads before.

I'm not sure how to approach freshening up the engine on this truck. This project is a full restoration, however, the engine was rebuilt in 93 by someone highly regarded. The block now has 40K on it, it's been babied, runs like a top and the oil is always clear. Doesn't burn either. So other than external components, gaskets etc., I'm dropping it back in as is.


HEADS:
>I thought perhaps to replace the head gaskets? There's no evidence of leakage. In your minds, should I replace the gaskets since it's on a stand anyway, or leave well enough alone?

>What's involved to remove and install heads? My concern is I don't want to screw a good thing up. Having not done this before, safe to assume you'd have to adjust the lifters afterwards? I haven't forgotten the builder's last words to me, "DON'T ADJUST THE LIFTERS". He was right too, smooth runner.

PAINTING ENGINE:
>Assuming I should replace the head gaskets, is it better to paint an engine with or without the heads bolted onto the block?

>How about the oil pan, bolted on the block or separate?

>How about the intake, bolted on or separate? Speak of intake, would you replace the sealant and gaskets? No leaks there either, but looks like a simple task if done right.



All input appreciated, thanks

[Grumpy old man]

If it's running fine and not burning oil why oh why would you pull the heads off of it ? If it's not leaking why take it apart ? you can clearly see it was recently rebuilt so if it ain't broke don't fix it ! don't disassemble any of it for paint just clean /mask and repaint .

[harpo231]

Double x on that ......

[71CHEVYSHORTBED402]

Oh thank GOD!

Okay........... I'll replace the oil pan gasket, clean her up and paint with everything mounted. I may replace the rear main, but haven't quite figured out what that is yet (yikes).

Thank you

[mongocanfly]

x3....if your worried about the heads and compression you can do a compression and leakdown test on it.....other than that I'd leave them on...
if your replacing valve and oil pan gaskets its easier to paint those with them off tthe engine..when painting the engine just tape up what you don't want paint on...and use a quality paint ....not the cheap stuff...
leave the intake in place unless there's a leak...

[mongocanfly]

if rear mains not leaking leave it alone to.....it will require (almost) removing the crankshaft...I've changed them in the truck before without pulling the crank by loosening the main caps and swapping it....but if you've never done it don't mess with it if there's not a problem. ..

[71CHEVYSHORTBED402]

Originally Posted by mongocanfly

x3....if your worried about the heads and compression you can do a compression and leakdown test on it.....other than that I'd leave them on...
if your replacing valve and oil pan gaskets its easier to paint those with them off tthe engine..when painting the engine just tape up what you don't want paint on...and use a quality paint ....not the cheap stuff...
leave the intake in place unless there's a leak...

Sounds good to me, thanks

[Black_Sheep]

Originally Posted by mongocanfly

if rear mains not leaking leave it alone to.....it will require (almost) removing the crankshaft...I've changed them in the truck before without pulling the crank by loosening the main caps and swapping it....but if you've never done it don't mess with it if there's not a problem. ..

Agreed, if it's not broken, don't fix it.

Clean it up good, scuff, wire brush any flaking paint, degrease, self etching primer, paint. The better the prep, the longer it will last. I prefer to paint engines assembled to reduce the possibility of chipping anything

[71CHEVYSHORTBED402]

Good info., all the way around, thank you.

So, on the subject of rear main (yikes), where about is that? Couple of images below that might help, and some questions too, in captions.

For years I thought the rear main leaked. But since the tear-down, I've discovered some of that was actually trans. fluid. I suspect the oil leak was from the pan.

I can say the oil I was using had some impact too. Leaked with Durablend for decades. If I recall, almost immediately after the rebuild. The leakage stopped or was near nothing with Mobile 1. I only used Mobil 1 once, which was the last change, but it did make a noticeable difference.

[jeffahart]

I was taught as a kid, only paint what you repaired on the motor. It works as a tickler. You can tell what you've fixed or what's new. I can look in my engine bay and at a quick glance be reminded of what I've done. Water pump, intake, if painted, I know I had my hands on it; and for a reason. Works for me, the way I was trained and never changed.

Another two cents... worth the price paid!

[Grumpy old man]

For some reason you seem bound and determined to open your engine up and I see no reason for it ? the plugs in the back are 2 core (freeze plugs) and the center cam bearing plug ,They all look fine and in good condition leave them alone . clean it prep it and paint it , The best thing you can do for it are frequent oil changes every 3,000 miles or sooner based on use ,these old engines like zinc use whatever oil you like but I stay away from synthetics in mine . If it ran fine and didn't leak button the whole engine up and paint it all at one time,once the paint is dry , Install a new fuel pump , oil filter , reinstall all the clean and painted accessories ,install new belts and bag it until your ready to reinstall it back in the frame ,Don't turn a 2 day project (with paint drying time ) into a pile of engine parts dancing around your garage floor . At the current pace your looking at 2 years + before your backing it out of your garage to go cruising .Don't add more work when it's not warranted .

your oil leaks stopped after the rebuild because it had all new gaskets installed ,It had nothing to do with oil brands . Remember your mechanic said don't adjust the valves when he was done rebuilding it ? well don't tear it apart either .

[71CHEVYSHORTBED402]

Ah heck no I don't want to open anything I don't have to, and won't, point taken. If I recall, the leaks came soon after the rebuild, pretty sure the gaskets didn't care for the oil I was using.

No kidding two years before I roll it out of the garage. I gots to get busy.

[A1971Blazer]

Agree on heads...don't pull them....just replace the leaky seals and gaskets ...paint and reinstall...

[Grumpy old man]

Look at all the fun you're having ! taking them apart is easy ,Putting them back together and having them run and drive without scratching any new paint or cracking new glass is were you start throwing wrenches at the wall ... Careful that's were the scratching the paint part comes in

[truckster]

I agree, if it's not leaking, leave it alone.

But to answer your earlier question, the rear main seal on two-piece RMS blocks is found next to the rear-most crank main bearing. You have to pull the bearing cap to get to it, and then you'll only access half of the seal. To access the other half of the seal, you can remove all the other main bearing caps to get a little wiggle room, or there's a tool that's made to pull the seal out from the end.

[a1vintage69]

Paint it all, I did

[71CHEVYSHORTBED402]

Originally Posted by Grumpy old man

Look at all the fun you're having ! taking them apart is easy ,Putting them back together and having them run and drive without scratching any new paint or cracking new glass is were you start throwing wrenches at the wall ... Careful that's were the scratching the paint part comes in

Oh yeah, so fun...............Heck no it wasn't easy, I track everything. Only concern I have rebuilding is getting everything lined up right. That and the maiden start -up. That and any damage.........So (*&)^)^ fun.

Originally Posted by truckster

I agree, if it's not leaking, leave it alone.

But to answer your earlier question, the rear main seal on two-piece RMS blocks is found next to the rear-most crank main bearing. You have to pull the bearing cap to get to it, and then you'll only access half of the seal. To access the other half of the seal, you can remove all the other main bearing caps to get a little wiggle room, or there's a tool that's made to pull the seal out from the end.

But but I don't wanna replace the rear main..........yikes.

Originally Posted by a1vintage69

Paint it all, I did

Yep.......What did you use?

[a1vintage69]

Originally Posted by 71CHEVYSHORTBED402

Oh yeah, so fun...............Heck no it wasn't easy, I track everything. Only concern I have rebuilding is getting everything lined up right. That and the maiden start -up. That and any damage.........So (*&)^)^ fun.




But but I don't wanna replace the rear main..........yikes.



Yep.......What did you use?

High heat Chevy Orange

[Grumpy old man]

I use Rustoleum it's always worked well for me ,

[old Rusty C10]

I agree with all on here don't fix what's not broken unless you have another $3000 to have someone repair what you fixed.. leave it all be... and I use the rustoleum engine paint too... make sure the block is good and clean mask what needs to be masked and have at it... two or three light coats as opposed to one heavy one and you're golden ( well chevy orange but golden nonetheless)

[truckster]

Originally Posted by 71CHEVYSHORTBED402

But but I don't wanna replace the rear main..........yikes.

There's no reason to if it's not leaking. In fact, if it's not leaking and you're not sure what you're doing, you just might create a problem that wasn't there before.

But you did ask...

[71CHEVYSHORTBED402]

Originally Posted by a1vintage69

High heat Chevy Orange

Nice. Not sure what I'm using yet. Might use Plasti Kote, apparently it's a dead-on color. Another might be POR15's stuff. Looks rich and supposedly very durable. I see Eastwood has a ceramic coat, etc. etc. etc. That Rustleum looks nice and rich too. I used Rustleum on my frame 20+ years ago. Held up REAL well, and that was with everything mounted & half a job prep. Too many choices.........