Chevy & GMC Vans

Gary, don't allow my cynicism to alter what you want to do with that engine. You probably know the right people to contact to get the job done right; it's just that I've yet to find them.

Rob,
I don't think you comments are cynicism at all.I have said all a long that just because you read in at mag,it ant necssery so.Using the type of info you got to remember those mag's are ad driven.

So the "real street" comments are more on the money.

Okay, I've got the damage report on the Chevy 350. It appears that whoever owned the GMC van before I got the engine ran it for a while with the blown head gasket. The drivers side head is junk because metal has been melted away between the center two cylinder combustion chambers. That's not a big issue, it just means I'll have to find another 193 head, and I already have. But the real concern now it that the deck has been terminally damaged between cylinders 3 and 5. It's definitely marked, but I had planned on having the engine decked as a matter of fact for the rebuild, so I'm going to go ahead and have it machined. The rest of the engine appears to be in good shape; no cracks or anything else that could make it scrap.

I also intend on being in the machine shop when the decking is done. I asked the owner if I could be there and I think he likes the idea of someone around who is interested in the machining process. So, it appears that next Friday machining will begin on this engine block. Cost of the decking is $118.
Also to be done at this shop will be the connecting rod reconditioning. Essentially, this means that the rods will be checked for trueness and the rod big end will be bored out to factory spec. Normally, you would think that the big end would have to be overbored like the cylinders are and an oversized outer diameter of bearing then installed. But a slick trick is done in this case; the rod end cap is machined down a specified amount and then re-installed on the rod. This makes the big end eliptical, not round, as you can imagine. The rod is placed in the rod boring machine and then the big end opening is brought back to round, factory spec.
Price per rod is $11.

The crankshaft checked out okay, too. That is, it's straight and rebuildable. The rear seal journal is scarred up, but I'm told that a stainless steel sleeve will fix that; as a matter of fact, the front seal on my 305 is riding on a repair sleeve and it works fine, so I have no concerns about that. The crank is now sitting at a different machine shop for the grinding operation which will be what's called '10/10'. That, for the uninitiated, is shop talk for grinding both the main and rod journals down .010 inch and means that oversized bearings will need to be used. No problems there. The grinding operation and the seal sleeve cost is estimated at $145.

I've been thinking about cam selection. I naturally won't be reusing the original. To ensure that the ECM be happy, I need a compatible cam grind. I can't go wrong with the original part number from GM, but I find myself wanting to find a roller cam that will do the job and retrofitting roller lifters to the block. There's two reasons for this; one is that the EPA has stopped the addition of a zinc compound that was added to engine oil to lubricate a flat tappet type cam, second is that a lot of the lifters available in the aftermarket are now from China and quality is hit and miss, at least from what I've read. If a lifter goes bad on a flat tappet cam, you have to replace the cam and all the other lifters because the break-in procedure has, in effect, married the lifters to the individual cam lobes. Sure, you can drop in a new lifter on an old cam, but the cam lobe in that position will get ground away in short order by the unmatched lifter. Or so I've read. My 305 has lifter noise from two cylinders that's getting louder all the time--these were no-name lifters out of a NAPA rebuild kit. I'm thinking I ended up with Chinese lifters. Can't really say for sure about that, but roller lifters neatly sidestep the above two problems. A roller lifter can be re-used with another roller cam since they don't wear-in to a specific lobe and the missing zinc compound means nothing to the wheel on the roller lifter.
A retrofit to a roller cam is just a thought at this point. But if I decide to go with it, it'll be one from Comp Cams--no other reason than that I like what I've seen on their website.

Hey, here's a photo of the damaged head from the 350. Quite a bit of material has been melted away between the combustion chambers.
The moral of the story is that you should not keep using an engine that has blown a head gasket.
There are red marks on either side of the melted area; the other red marks in the photo are around what looks to be a crack.
By the way, anybody know what the cc volume of the 193 head is? I'm curious.

Rob,

Take a look at the specs for a LT1 camshaft from a B-body. These have been proven to work well in TBI cars, both performance wise and being ECM friendly.

They are a roller cam and can be found used in good condition VERY cheap....

I admittedly know very little about engines,so I appreciate it when someone takes a couple minutes to explain the reasons why their going about doing something a specific way,makes it much easier to understand the process,thanks Rob.

CD, thanks for the tip about LT1 camshafts; I'll look into it. I'm really leaning toward a roller cam--no cam break-in at all with those.

Zam, glad you liked my rather long and rambling post. There's a lot I hope to learn about engine machining with this 350. I hope to talk the shop owner into letting me do the machine work on whatever I can with this engine. Of course, that's after he shows me how...

Rob,
Keep in mind you will have to cut the intake after decking the block to get the intake to seal correctly.

Like Zam says, Rob, it's great reading what all is involved in the buildup as I have also never messed with an engine. I also like the prices being listed so we have an idea on costs associated with an R & R.

I agree with Deano and Keith about your posts.It's a solid post with pricing being listed.(Also shows ways you can save some too.)I have tried to get one place do the machine work and someone else involved in the short block and some else doing the finsh work.The key being getting as many set of eyes looking at it for check and balances.

I agree with you, Gary--having more eyes on the work should be a help.
Also, you bring up a good point about the intake fit after the decking operation. This is a question I asked about at two shops before I decided which one would do the work.

First Shop: "No need to worry about the intake manifold fitting after we do the decking; Chevy engines are designed with a sloppy intake manifold fit, the gasket will take care of it. Just be sure and use a lot of gasket sealer."

Second Shop: "After decking the block, a certain amount of material has to be removed from the intake side of both heads to maintain proper intake manifold fit. We have charts that tell us how much material to remove for the amount of deck height reduction."

While the First Shop might be correct about the intake sealing correctly, their answer was just plain wrong to my way of thinking. Second Shop had the right answer, as far as I'm concerned. As you can imagine, Second Shop will be doing the deck machining.

But I'm not going to rule out First Shop for other machining work when the time comes.

Rob,

Here's a shot at a cheap stock LT! cam for you.

http://www.9c1.net/forum/index.php?showtopic=171817&hl=

Thanks, CD. I sent the poster an email asking him about it.

Wow, nice thread Robby. I definitely agree on machining the intake after decking the block or milling heads. ZZ's intake is clearly noit sitting as centered on the heads as before the rebuild. And they only milled the heads 10 thou.
As well, depending on how much you mill from the heads, the dissy may have to be shimmed as well

Rob,
I believe for every 10ths it is equal to 1/2 point of compression.That maybe good or bad considering what you want to do with it.