92 454 TBI stock rebuild

norcalwrenchin · September 21, 2016

Hey everyone. So I have a 92 k2500 with the nv4500 and 454. The trans was in need of a rebuild, so I figured let's do the motor too. The truck has 250 k on it. I was just going to slap gaskets in it and not worry about the bottom end because it wasn't making any noise, but I pulled rod and main caps and the bearings are out and need to be replaced so I'm doing all of that also. My first of many questions I'm sure it is does anybody know where I can find stock cam specs for the 92 454 or where I might be able to purchase a new stock pattern Cam and lifter kit? Thanks in advance really looking forward to having this old truck back on the road LOL

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grampadirt · September 21, 2016

Welcome to the site I've searched and searched for the stock cam profile for my '95 454 and can't find anything on it,if you find info for yours I'd be interested to see where you found it.Good luck with the rebuild.

ifixedit · September 22, 2016

Since you're tearing the engine apart you could certainly get away with just a good budget overhaul. Yes, replace the rod and main bearings as I'm sure with that many miles they are worn out, this will restore oil pressure and ensure all parts of the engine are getting an adequate supply of oil. Do check your rod and main journals on the crank for any scarring or scuffing, if they are nice and shiny you're good to go. Replace the rod and main bearing with standard size, I wouldn't recommend under size. Next is to inspect the cylinders, if there is little or no ridge up at the tops of the cylinders you can get away with just a re-ring which will restore compression. As long as the pistons are in decent shape, re-use them. Here again I would not consider replacing the pistons (unless you want to over bore the cylinders) because it GM fits each piston to each cylinder at the factory, so replacement pistons would require going with a cylinder bore and over size pistons to be sure all is correct. Take note of what piston came out of which cylinder so you can put it back together exactly the same way. Clean up the cylinders before re-assembly with a glaze breaker, do not use a ball hone as it's pretty easy to get carried away with them and end up oversize, you just want to dull down the shiny cylinder surface to help the rings seat, that's all.

Next the cam and lifters... FIrst, you will want to replace the cam bearings, don't just throw in a new cam. If the cam bearings are worn which they likely are you will again defeat your work by causing another area in the engine that will pass too much oil causing another area to perhaps not get enough oil. As far as the stock cam, I wouldn't worry about getting the exact replacement but I'm sure a call to a local dealer parts counter would tell you what you need. I'd instead check with either Jegs or Summit, perhaps even Comp Cams for a different cam. They will all recommend something along the lines of an RV cam which will likely give you a nice bump in power over the stocker anyways. From there, other than new gaskets, I'd also look at new valve seals, a timing set and a new oil pump and you should have a fine running engine. By the way, if this is a standard flat tappet cam engine (i.e., non roller cam) you want to do a proper break in procedure of the cam with the proper oil, I would recommend Valvoline VR1 racing oil which has all the needed additives to protect the cam which nearly all other oils do not have, don't take a chance here, not worth it or you will be replacing the cam again in short order. I'd break the engine in with straight 30 weight.

I hope this helps.

Edit: I took a look at your pictures again and yes, your cam bearings are shot and need to be replaced.

norcalwrenchin · October 17, 2016

Thanks for the replies! This is kind of a back burner project as I'm daily driving my 77 k20 burb. Yeah all the bearings worn pretty good. How about wrist pins? Any sense in replacing those? I'm just waiting for rings, and funds for a cam kit and I'll get her back together. Then I get to tear into the nv4500 haha.

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norcalwrenchin · October 17, 2016

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norcalwrenchin · October 17, 2016

Also, anybody know what this plug is? It had some like, JB weld or something all over it....

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ifixedit · October 18, 2016

Don't worry about wrist pins, they'll be fine, they are a very hard tool steel and likely are still as good as new. From what I can see in the pictures it certainly looks like what I described earlier, it's a good candidate for a budget rebuild. The cylinder bores look decent and a simple glaze breaker treatment may be all that's needed. You're gonna want a good ring compresser for reassembly. You're also going to need to either buy or borrow a couple other tools, a cam bearing removal / installation tool and an oil pump priming tool. Importan! take note of the orientation of each cam bearing before you remove them, you want to pay attention to the orientation of the location of the oil holes of the cam bearings as they were installed and put the new ones in the same way. As far as that plug goes, looks like someone did a little 'Jimmy rigging' at some point on the intake, while you're at it I'd replace the stock intake with a good aftermarket.

grampadirt · November 26, 2016

Any updates? As ifixedit said,an aftermarket would be a good idea,these intake manifolds on 454s suck.Edelbrock is about the only company who makes one for these engines TBI engines.