Could I get some opinions on a very cut rate approach to rebuilding a 390? In short, have folks simply replaced some key components without any machining work and been happy with the results? Below is more detail on that approach, but in essence that is what I'm asking if you don't want to read all this.

** I'm OK with risking SOME limited dollars on what turns out to be just an OK result that will get this truck on the road and avoid catastrophic problems like a jumped chain. I'm not OK with shortchanging anything that almost guarantees damage to the engine. **

As background, the truck I've got was bought as a non-runner. It 'ran when parked' supposedly many years ago. The guy I bought it from was decent but there were some grey areas with its condition and was 'sold for a friend'. In short, this may or may not have actually run. It's out of the truck, still connected with the transmission as one giant lump of 50 year old dirt, grease, oil, and grime. Am cleaning as I go.

I soaked it in MMO extensively and it turns over by hand just fine. I had the oil analyzed - very heavy on gas (poured out like water), new starter added by someone. Some nickel and copper in the oil too.

My best case hope here is that the gas is in the oil because someone tried to get it going unsuccessfully combined with some worn rings allowing fuel to get into the sump. And the bearings beginning to see some accelerated wear. I'm assuming here that it's the crank shaft bearings.

I've been reading Barry Rabotnick's book on rebuilds and while excellent he makes the assumption the heads and block will be sent to a machine shop. That's a damn big assumption. My goal is to return the truck to operating condition with the understanding I may need to do more work on it later. I'm working on it outside. Which can be a challenge. There is no garage. So there are limits on what I can do.

Can folks comment - good or bad, on the following approach - none of these changes would be using performance parts, all stock or close to it, no change to compression, etc. So no new demands on the engine. The transmission is a C6.

1.) Replace timing chain and timing gears, gaskets.
2.) Replace all gaskets (heads, pan, etc).
3.) Replace water pump
4.) Replace lifters, pushrods, valve springs, valves & seats
5.) Replace crank shaft bearings
6.) Replace oil pump & screen
7.) Keep cam shaft & original bearings
8.) Keep pistons & rods
9.) Replace piston rings
9.) Hone cylinders

What I wouldn't be doing: anything a machine shop would do. That means no magnaflux, no head milling, no checks for crankshaft bore alignment, no checks for cylinder round, no removal of cylinder lippage.

But...a rod or piston could fail. Wear in the cylinders or crank bores could accelerate with new and now closely fitting rings / bearings that are not well aligned to old wear patterns. A head would spring a gasket leak because it's deck is not flat.

I can only measure so much with a cheap pair of calipers. And a significant limitation is knowledge of what is likely to go wrong and what is less likely.

Alternatively, I could just compression test the cylinders and put this oily mess back in the truck. With no idea on it's performance. I can't afford to bring it to a shop right now. Money is always tight.

Rabotnick is knowledgable but not helpful for the amateur who has a pretty limited budget.

 

If keeping the cam ... then keep the lifters and make a holder to keep them in order while working so that each lifter goes back in the very same hole to ride on the very same lobe as it come out. No need for new lifters and a whole 'nother break in procedure with it's risks.That cam is "mated" now to those lifters in those same holes. If lobes are wiped or lifters concave ... then consider replacement. A piece of 2x4 wood, about 10-12" long with two side by side rows of 8 holes each, 1" diameter drilled with a spade bit, then a piece of thin plywood on the bottom will give you a good "holder" for a lifetime, 16 holes, label the holder for front. l< :::::::: l

Unless an issue is found, I would not change push rods or springs or even valves. We often just had the guides knurled and fitted new seals. If valve stems are worn bad or a valve is burnt, then replace it. Valves can be lapped in as they are being reassembled on the heads.

If the timing chain is worn bad or the sprockets are nylon coated, then replace them. If the sprockets are bare metal and the chain is still not overly sloppy, I'd keep it.

Do get the heads resurfaced.
Good time to have valve and seats retouched too.

Do replace any freeze plugs in the block.

 

The problem is most of your questions can't be answered until you pull it down and see that you have.

How bad does it need bored ? does the crank need turned ? are the valve guides and seat toast ? until you look at them no judgement call can be made. more often than not shortcuts become the long way home. tear it apart and we can help you decide.

 

Bear, I like your points. Good stuff. Yes on the freeze plugs, forgot to mention, but hadn't thought of keeping those other items since keeping the cam. Thanks.



Ugh. Yes, I know, I know. I was thinking that before posting. But was hoping somehow I could get some magic "yeah I've done it, no problems". The question really becomes how far do I go before saying nope and buttoning it back up. I'll have to think on this some more. I tend to leap before thinking.

 

You never know you might get lucky. it the bores aren't real bad you might be able to hone it and put some new rings in. if the crank is not too bad put some bearings in and go.

I'd plan on a new timing set, gaskets, freeze plugs, cam bearings and lifers at least. rockers are probably ok and see if your cam can be reused.

Your biggest problem is most likely the heads, if they don't require some extensive work you're going to be real lucky.

You just never know until you're looking at it. go in expecting the worst and hope it's better than you expected. that way you're prepared. if you're lucky all in will be under 1k, if it's not too bad just heads bearings and rings 1-2k. if it's a wreck and needs everything 3k to 3500 . maybe a bit more I'm just starting on a 429 and that's the only engine I've done in a year so prices have gone up I'm sure.

 

I forgot ... unless replacing the water pump, if plan is to reuse it, maybe store it in a bucket with the drained coolant, keeps the seals wet. I've seen a few that never leaked start leaking after being left laying on a dry floor.

 

I've already got a new pump, had never heard that one, but don't doubt it. As far as sixpack's points, it's helpful to hear what things are costing now a days. My pricing expectations are unrealistic and lost in a few decades ago. I better tread lightly on this part of the project. before tearing everything apart. Glad I asked.

 

The question I would ask myself is if it ran when parked why the engine was removed.

 

The prices I'm talking about are top end stock replacement parts and the high end machine shop ,all tear down and assembly done myself. nothing fancy just a solid rebuild, go for performance and the sky is the limit.

If you used bargain parts and a backwoods machine shop you might cut those prices some. but if you're not in a position to see it through maybe it's best to see what you can do with it as is. once you tear it apart you're committed.

 

If you are going to replace the piston rings, and there is ANY ridge at all at the top of the cylinder, you will need to get a ridge remover and take out the ridge. If you don't you will likely get broken piston rings and/or damaged lands in the pistons. If you don't want to remove the ridge, clean & reuse the same piston rings and put them back exactly where they were when you took them out.

 

There's never enough time to do it right the first time, but there's always enough to do it again.

 

LOL. I have the time. I don't have the cash (or roof) for it at the moment. Good point on the ridge remover Ozzie. Thank you.

 

If you need a ridge reamer you will be boring it for sure.

 

It's not to say that I haven't done this kind of stuff myself. I've got a couple engines in this corner of the country that have nothing more than a turd-ball hone and a set of rolled-in bearings running around that are completely trouble-free. Three of them drive past my house nearly every day. I am saying that there's a right way.....and a get you by with the money you've got way. The latter usually costs a guy a couple times and these days, time ain't free.

I put together a 360 a bit over a month ago and machine work/parts were just under $2400. The 460 before that was a bit cheaper as I didn't bore it since it was a reman that had a case of infant mortality (didn't make the first oil change) and it just needed pistons, bearings, and a cam. I had about $1000 in it (including balancing). Two prior (a 400 and a 390) were also at opposite ends of the spectrum; $5600 and $2100 respectively. I've got another 460 to do this month (97 F350) and expect it to be in the $2300-$2500 range as well.

The "just make it run" rebuilds have been in the $400-$500 range then add a little for a camshaft and lifters if needed. Head work adds about $250 too. I have two 7.3L Powerstrokes here that got the same "rebuild" and they're just fine.

 

yeah. well as i said before, i'm thinking now i better slow down on this part of things. if i get it in pieces, then i've got problems because i'm committed, as someone said above. i'll probably start with a battery hookup since it spins freely and test compression. depending on that revisit this thread and see what people think. at the very least a timing chain kit is some measure of 'half way' care. i have a clovis which is a good maker. i think it's a solid truck, though every neighbor and passerby seems to say otherwise. "when is that old thing gonna be done?" every once in a while I get a car guy by. that keeps me going! thanks gents. john