4.3L to ?? swap.

[454cid]

Boy.... I should have stayed the Hell in bed today. I can't seem to catch a break on this engine. I tore down only the essentials to prep the engine for pressure washing. Behold, the passenger side of the block, covered in 33 year old 5W-30, with no clear place it could be leaking from.

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You sure it's not just the valve covers? My 454 with silicone gaskets eventually leaked, and it was quite a bit of oil. It smoked all the time from running down onto the exhaust manifolds even thought I'd pressure wash it.

 

[Schurkey]

I don't know what swirl port is. Do I want to? The machine shops says that the heads are sodium filled and already have the hardened valve seats.

Swirl-port heads have a "ski-jump" cast into the intake runner by the valve guide. Essentially, half the intake port is blocked-off. They don't flow air very well at all, but they do make for good in-cylinder turbulence. They're fine at low rpm. They're terrible for "performance".

The same design concept is used on the 7.4L Vortec intake ports--they're more related to the TBI swirl-ports than the L31 Vortec heads in that regard.

Hardened exhaust seats are universal since about '72 or so. Sodium-filled exhaust valves are not an advantage, they're heavy and not needed. But they're what you have, and it's probably not worth the hassle of replacing them.

Anyway, the heads are at the machine shop getting cleaned and checked. Nothing more. I'm not putting $$$ into garbage. The valve stems are getting cleaned and checked, as well. If they are straight, I'll use grinding compound and a valve lapping tool. If not, I'll replace just the ones that are bent.

Make sure you buy reasonable valve-lapping (not "grinding") compound. The common crap sold in most parts stores is so coarse as to be unusable. It's like playground sand in a grease or water-based carrier.

I bought a can of "Clover" 400-grit lapping compound, and if I were doing it again, I'd get finer-grit than that, but it's acceptable and I've essentially got a "lifetime supply".

The big deal is having usable valve guides (not worn-out) and usable valve stems (not tapered/worn out). If the guides and stems are good, lapping the valves is likely all you need--but it's worth looking at the valve seats and valve faces to assure they're in adequate condition. Same with inspecting the valve tips where the rocker arm pushes on them. Look at the rocker arms where they touch the valve tips--common for the rocker arms to be worn-out there.

Car wash? LOL! I have a 2500 psi pressure washer and a perfectly good driveway.

That's what I use. I have to admit...having heated water instead of cold would be nice. But cold works, and I don't have to drive the parts to the car-wash.

Ah yes! The V8 vs V6 radiator hoses! I do have the top hose but not the bottom. Thanks for the reminder.

The V-8 hose may not be long enough to reach all the way back to the V-6 thermostat housing. But you might get lucky. I don't know if there's such a thing as a V6 hose intended for the bigger/wider radiator. MAYBE you have to cut the hose, and add a length of metal tubing clamped in place to get the hose to reach. If so, be sure to bead the ends of the tube so it doesn't slide out from under the clamp.

K truck mounts i believe take 3-1152R. At least that was the part number that worked for me

That's not what Summit or Energy Suspension was showing for the K1500 application. But I should look into those.

I have ZERO idea why Shurkey keeps claiming the tabs are at the wrong angle,

Because the OEM mounts have the metal supports "straight up 'n' down" while the Poly cushions have them tilted at a ~20 degree angle.

for anyone interested I recently bought Anchor motor mounts for my squarebody and they were made in USA and seemed to have thicker gauge steel than ones i've seen in the past. p/n 2292 2wd application. maybe the ones for gmt400 are the same.

The GMT400 mounts are not the same as the Squarebody mounts; and there's (at least) 3 different styles of GMT400 mounts--2WD V8, 4WD V8, V6, (2- and 4WD?) perhaps a version for the Diesel, and south of the border the GMT400 could be had with an inline 6. The only ones I've looked at are the 4WD V8; and every set I looked at seemed to be made by the same factory but put into different boxes with different brand-names. Thin steel shell. I have heard--but not verified--that the 2WD V8 version is still available from GM, and is still made "right".

 

[DeCaff2007]

You sure it's not just the valve covers? My 454 with silicone gaskets eventually leaked, and it was quite a bit of oil. It smoked all the time from running down onto the exhaust manifolds even thought I'd pressure wash it.

Replaced both valve cover gaskets already. Why would it be one side pouring down and not the other?

 

[Erik the Awful]

I don't know what swirl port is. Do I want to? The machine shops says that the heads are sodium filled and already have the hardened valve seats. He mentioned that only the "bigger trucks" would have had that (this engine is from a K2500).

I rebuilt a set of 198 heads, which are supposedly identical to the 810s. The swirl ramps in the port bowls block flow, but removing them makes the ports way too big. Also, the machine work on the bowls and transitions is ugly. Finally, the combustion chamber is a bit narrow around the intake valve, which shrouds the valve and limits airflow on that side of the valve. They're in the running for "worst small block Chevy head ever". Sodium-filled valves were a trick idea to help keep the valve faces cool, but from what I've heard it didn't really pan out to any significant benefit.

If you keep the heads, I'd do some cleanup porting work and build for gas mileage and torque.

The carburetor picked THAT MOMENT to fail and has to be rebuilt.

Every time.

 

[DeCaff2007]

So what about these valve cover gaskets? Is there something better to stop the leaking?

 

[Schurkey]

First Guess: Just need "new" soft, pliable valve cover gaskets instead of ancient, hardened gaskets (and appropriate torque on the valve covers.)

Straightening flanges and such used to be a big deal--and it's worth looking at--but most of that went away with the centerbolt valve covers.

While you're in there, though, verify the PCV system. If the crankcase is building pressure, you can have all sorts of gasket and seal leaks.

 

[DeCaff2007]

Gaskets are already brand new. The center bolts are torqued, and it still leaked at that point. I'm supposed to be picking up my parts from the machine shop already, so I might just junk this 6 cyl sooner than later.

 

[DeCaff2007]

I have good news and bad news. The good news is, my parts are back from the machine shop. My "unique" block, lol, is all cleaned up, ball honed, and the gasket surfaces sanded.

The heads look A LOT better, now that they've been cleaned and checked. I already know that these heads aren't anything special, and that's ok seeing as how they are only in "fair" condition. When I'm ready, I'll put the valve train back together that's the end of that.

Now the bad news. The crank is 1 one thousandth out of tolerance on the 1-2 rod journal. That's enough to need the rods cut .010 under. Everything else is within spec, to including the main journals. However, I was told that after the crank is serviced and the rods are cut, I can use standard size bearings. That, along with trolling YT for some info, has answered some big questions that I had had.

HA. I'm typing this like I know what I'm talking about. I'm literally just paraphrasing the machinists notes from the invoice and posting the results here.

OH! I also had the pistons all cleaned up and checked. I haven't opened the box, yet, so it'll be a nice surprise for both me and the forums when I crack the tape open on that.

Here's my pile-o-parts, not yet unwrapped.

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Now, for the worse news. I have $1800+ tied up in these two engines and cannot use either one of them due to needing more parts. I might as well have put another $1500 into the purchase price of the 5.7L and that would have netted me a cheap crate engine (minus the accessories and the intake manifold.

My point is that now I have to put additional time and $$ into something that was SUPPOSED to be drop in and go.

Lastly, the best part is, that work has gotten busy to the point where I'm not sure that I'll have much spare time... until further notice. Lovely.

 

[Schurkey]

these heads aren't anything special, and that's ok seeing as how they are only in "fair" condition. When I'm ready, I'll put the valve train back together that's the end of that.

"Fair" means "usable"...right? You're expecting the engine will run OK short-term with them?

The crank is 1 one thousandth out of tolerance on the 1-2 rod journal. That's enough to need the rods cut .010 under. Everything else is within spec, to including the main journals. However, I was told that after the crank is serviced and the rods are cut, I can use standard size bearings.

Standard-size MAIN bearings. The ROD bearings will be .010-under to match the freshly-machined rod journals.

I have $1800+ tied up in these two engines and cannot use either one of them due to needing more parts. I might as well have put another $1500 into the purchase price of the 5.7L and that would have netted me a cheap crate engine (minus the accessories and the intake manifold.

My point is that now I have to put additional time and $$ into something that was SUPPOSED to be drop in and go.

Welcome to "working on vehicles", where everything costs more than you'd expect, in time, money, effort, and enthusiasm.

Lastly, the best part is, that work has gotten busy to the point where I'm not sure that I'll have much spare time... until further notice. Lovely.

Excellent. You'll be building-up your cash reserves for the next disappointing turn of events with the engines. Or the suspension. Or your house.

 

[DeCaff2007]

"Fair" means "usable"...right? You're expecting the engine will run OK short-term with them?


Standard-size MAIN bearings. The ROD bearings will be .010-under to match the freshly-machined rod journals.


Welcome to "working on vehicles", where everything costs more than you'd expect, in time, money, effort, and enthusiasm.


Excellent. You'll be building-up your cash reserves for the next disappointing turn of events with the engines. Or the suspension. Or your house.

Run OK, yes of course. I don't expect a tire-burning power house with those smog-era, worn-but-usable, iron paperweights. Honestly, I don't think this SBC will ever see much in the way of power upgrades. That's what my T/A is for. Hell, we have an 83 Grand Prix waiting it's turn with essentially the SAME SBC, except that it's a smog suffocated 305. The Wife and I are planning our first LS swap on that. Should be cheap and easy

Standard-size MAIN bearings. The ROD bearings will be .010-under to match the freshly-machined rod journals.

Now see, I wouldn't have figured that. I've learned that my brain works completely a55 backwards when it comes to things like this. To me, it seems the bearings should be .010-over to compensate for that amount out of tolerance. But, I digress.