GM Crate Motors

Has anyone ever bought a GM OEM Crate Motor ? I have 1990 Chevy Silverado C \ 1500 5.7 TBI. Several places offer a replacement long block that is brand new, same spec's as the original. I bought my Truck new in Jan. 1990. It used over 2 quarts of oil between oil changes. I looked in my Service and Unit Repair Manuel's and noticed the small block V-8's did not come with valve stem seals on the exhaust valves. I contacted the dealer about the oil usage, he claimed GM's policy was it had to use over 4 quarts of oil between oil changes to be considered excessive usage. He had no answer about no valve stem seals on the exhaust valves. I had to have seals installed myself before the oil usage went down. I can't figure out why they were not installed at the factory. I now have almost 500 thousand miles on the motor and it is loose and I need to rebuild it or buy another Engine. The crate motor sounds like a good deal, 2000 bucks, free shipping and no core return. I need to find out if it has valve stem seals on the exhaust valves, or if it is like the original motor. Has anyone on the forum ever used the gm crate motor for 1988-1995 gm trucks? Thanks, Mike Duckworth.

Whoa, 500k on the original motor??? When you say loose, what do you mean? What's the oil usage like now? What were your oil change intervals, what kind of oil did you use and what filter?

I had good luck with the junkyard replacement I got. Supposedly had 145k miles on it and came from a 1995 G3500 2wd automatic van. Same casting number as the engine it replaced, IIRC it was 10654727 which was popular with trucks. Anyway, I wasn't told if it was a 4 bolt main or has a roller cam. I'm assuming yes on the 4 bolt and no on the cam. I've been running Valvoline full synthetic 5w-40 with Purolator Boss filters and changing it every 3k, uses about half a quart by the time it gets to the change interval but I never add oil since it's still within operating range. So far I'm 1,000 miles into this oil change and it hasn't used any. Seems to use oil toward the end of it's OCI.. I read a lot of GM sales brochures and right around 1991 they claimed they made internal improvements to the 305/350 engines but never said what that meant. Compared to the old engine though, this one makes me smile and was well worth it, better oil pressure too.

The old engine used anywhere from 3/4 to a quart of oil every fill-up, so about 300 miles. Not to mention it burnt up a valve on cylinder #1. Had only 225k on it but must have lived a hard life and been overheated a bunch of times.

That's awesome... 500K. I've never heard of the valve seal deal. I will be ripping apart my old one soon as it will be used for a core for another project. part of my barter deal I have going on. I will certainly inspect it and see if seals are there...you have me curious.mine used a qt. in 5k miles if that. It still ran strong at 250K unmolested miles, these things are awesome, they run forever if you treat them right and you are a testament to that for sure. I abused mine for the last two years as I knew I had a new one coming and she still didn't quit.

I do know some of the "big" rebuilders are assembly line quality and all use used parts and just throw new bearings and rings and basic valve jobs and get them out the door. and I've heard some stories. Now the actual GM ones may be somewhat better. call them up and ask about their reputation , can't hurt. OR you could find a local guy that may have one done and can give you some better build quality in regards to machining processes and that personalized touch..
YOu could take this approach also: Find a used core. Strip it down yourself ( not hard) do some sweat equity so to speak. take the parts for machining and or assembly based on your comfort level with doing those things. Get a top quality valve job, a good bore and hone and some better quality components and you should be good for 500 more, then of course re-sell your core all the while keeping driving your truck, if you do something like this you can dictate your cam, and other components as needed. then you get the pride of saying "i built it". no better feeling seeing an engine "you' built come to life....

I have a crate engine in my 89. It has 75k miles on it now and uses no oil between changes. No smoke at start up either. The engines comes with a 3 year 50k mile warranty. I think you would be fine with one of them. GM has a rebate program going on for these engines now. I would find a good dealer and go see them. Good Luck!

Even If you had to install seals, that would be a hell of a deal for another 500k. How many transmissions have you been through

Ed Tyer said:

I have a crate engine in my 89. It has 75k miles on it now and uses no oil between changes. No smoke at start up either. The engines comes with a 3 year 50k mile warranty. I think you would be fine with one of them. GM has a rebate program going on for these engines now. I would find a good dealer and go see them. Good Luck!

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Unless I'm reading the fine print wrong, the rebate requires purchase and installation at a dealership, right?

Once I heard that oil seals on the exhausts would not allow enough lubrication and would result in early valve guide wear..

Anyone KNOW more about that??

DerekTheGreat said:

Whoa, 500k on the original motor??? When you say loose, what do you mean? What's the oil usage like now? What were your oil change intervals, what kind of oil did you use and what filter?

I had good luck with the junkyard replacement I got. Supposedly had 145k miles on it and came from a 1995 G3500 2wd automatic van. Same casting number as the engine it replaced, IIRC it was 10654727 which was popular with trucks. Anyway, I wasn't told if it was a 4 bolt main or has a roller cam. I'm assuming yes on the 4 bolt and no on the cam. I've been running Valvoline full synthetic 5w-40 with Purolator Boss filters and changing it every 3k, uses about half a quart by the time it gets to the change interval but I never add oil since it's still within operating range. So far I'm 1,000 miles into this oil change and it hasn't used any. Seems to use oil toward the end of it's OCI.. I read a lot of GM sales brochures and right around 1991 they claimed they made internal improvements to the 305/350 engines but never said what that meant. Compared to the old engine though, this one makes me smile and was well worth it, better oil pressure too.

The old engine used anywhere from 3/4 to a quart of oil every fill-up, so about 300 miles. Not to mention it burnt up a valve on cylinder #1. Had only 225k on it but must have lived a hard life and been overheated a bunch of times.

Click to expand...

I changed oil every 3000 miles, I used penzeoil 10w 30, once I put valve stem seal on the exhaust valves it drop down to 1/2 a quart between changes. I believe they probably improved the engines by 1996 when they started putting roller cams in them, those 2nd generation engines
were much improved. My 1st generation L05 is using about 4 quarts of penzoil straight 40w in 3000 miles. Its leaking as much as it is burning, both main seals are wore out after 500,000 miles, it runs good though. I just am undecided on weather to rebuild this one or just get a new engine. I just rebuilt the 4L60 transmission this year, it got to where it would not back up until it was warmed up, lip seals for reverse were damaged from heat. Its been a good truck and I still work on it. These new Chevy trucks, I don't like the way they look, they are to big for me and have to much electronics. I wish gm would have a remake on the gmt400 platform

Stem seals on the exhaust valves, eh?
When did you notice your engine first started to burn oil? At how many miles did you end up replacing the exhaust stem seals? You ever replace the intake side?

You're better off just rebuilding a GMT400. I don't like new vehicles either, nothing about them appeals to me. If it's got more than one camshaft, I don't want it.

Tha

arrg said:

Unless I'm reading the fine print wrong, the rebate requires purchase and installation at a dealership, right?

Click to expand...

Thanks for the info. That sounds like the best deal to me.