What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Need help figuring out exact specs. on '90 Jimmy 1500

S

scpaul

1/2 ton status
Joined
Oct 2, 2016
Posts
278
Reaction score
30
Location
central area of S.C.
I have a '90 Jimmy 1500 that has around 150K miles. It was parked about 8 years (?) ago because of the price of gas, about 6 mpg, more than anything else. It was bought new by our family, so I have a pretty good idea of the history of it. It's all numbers matching, so I don't want to get too radical.

I used to work/play with automotive stuff many years ago, around 1974, I had a street car running low 13's on street tires. ALOT (everything) has changed since then. I started looking around to find the fine specs on this vehicle and found that somewhere along the line they changed the rules. It has the factory towing pkg. with a load leveling receiver hitch, trans and engine oil coolers, HD radiator, etc.

When I was messing around with vehicles anything, especially a truck, with a tow pkg. had a 4 bolt main block. What I'm finding using the VIN and internet to figure out what I've got.

On one rebuilder's site, he had 2 listings for a "K" code engine in the same list. One inside of the other according to dates. Like (just an example) it says that "K" engines ran from '87 to '95. Farther on down the same page it says that "K" code engines ran something like '88 to '93, just an approximate from my memory. It says that some of the years had a mech. fuel pump hole, others don't. I think that it was the later ones that had a different intake, ctr. bolts different, and inside of intake set-up for TBI. Both say 1 piece rear seal. I've got to look that one up. One group has the possibility of having 3 different heads; 191, 193, or 810 head castings.

At this point I figured that I'd ask somebody. Then I saw one was called a 350L130 and the other was something similar, 350L150? ( guessing).

With all of the things that they are doing with computers now days, I don't know if I could be doing something wrong if I put the VIN in here.

Who is willing to help me (old phart) try to understand some of this new stuff and how to deal with it, and yes, I'll probably wind up being a C.P.A. (Capitol Pain in the Azz). Some say that I have an inquiring mind others say that my memory's gone. I was around in the 60's and 70's.

I found where it says that this mtr. is 9.25/1 compression, which is more than I expected. I figured 8 or 8.5 to1. It says that it has a nodular iron crank and some other things that don't sound like they should have been put on a vehicle with the factory towing pkg. (7K Lbs?), from what I think I'm seeing, this is going to have to stay pretty much stock unless I want to sink my whole S.S. check into it every month. I have heard that canned cat food burger patties is pretty good fryed in bacon grease and put on a bun.....Just a joke, but I bet onions would help it.

I need an education or at least enlightenment. Thanks everybody, in advance, for just putting up with my ignorance, Paul
 
Glad you got a laugh out of it. I've always tried to keep things light. It has gotten me in trouble more than once.

I'm just wondering things like how do I find out which heads are on it, Iron crank was junk years ago, etc. Have you seen any problems with putting a vin out? I'm thinking that someone would be able to point me in the right direction to get info.

Thanks, Paul
 
There are several CK5 guys who work at dealerships and can look up VINs if you ask. I know that @ZooMad75 has offered to look up RPO sheets in the past. But I thought you already had your option sheet in hand. :dunno:
 
There was not much variation in engines that year for the Blazer/Jimmy. It either had a gas 350 TBI (Engine RPO code L05) or a 6.2l diesel. That's it - those were the only two engines GM was putting in Blazers/Jimmys that year from the factory.

The internal engine construction had nothing to do with the tow package inclusion or lack thereof. It did/does indeed have a nodular iron crankshaft, one-piece real main seal, and most very likely 2-bolt main caps in that truck. They put L05s in 1/2-ton through 1-ton trucks that year - the 2/4- and 1-ton trucks were supposed to receive 4-bolt main L05 engines. It's the same engine block casting either way.

The head castings had some slight variations, but nothing too noteworthy between them.

I will say that if it's only getting 6MPG then something is wrong with it.
 
I might be able to pull the RPO (regular production option) list from the parts catalog if I have the VIN. But for the most part the Longbedder is on the right path, that's all a Blazer had available.
 
Thanks, I don't have time this minute, but I will get back with y'all. Some of the info I'd already found other I hadn't. Gotta run, thanks, Paul
 
Thanks, I'm sorry that I couldn't respond better before but I had something I had to deal with that wouldn't wait.

I do have the original window sticker. I was asking about the particulars on the different things like the the heads since the research says that it could have one of 3 different head castings. I found a place on line that gives the shapes on the front of the head for ID. purposes. Like when I was coming up if you had the double hump heads, you had the good ones. I can't see the front of my head for all the stuff in front of it. I was going to make sure that it was/wasn't a 4 bolt block, which I now know that it's a 2 bolt. It used to be that a towing Pkg. was automatically had a 4 bolt block, bigger brakes, if available, HD trans, trans cooler, lower gear ratios, etc.

Is there any reason that I shouldn't put the Vin on here? If not, I will. I don't know of any reason not to, but now days who knows. Just let me know.

Another question; is there a spray on insulation that would be suitable to spray the fiberglass roof before or after I paint it to help keep it cooler inside? I plan to spray the inside too. I've got to re-do the fabric part of the headliner anyway. I've heard of ceramic sprays I think, but don't know if it will work for this and if money wise, if it's worth it.

Thanks again y'all, Paul
 
I think you are mixing up generations of engines lol.

Of course "camel hump" heads were still SBC heads, but they were gone long before TBI. If I remember my numbers right, your engine will have '193 heads, which are swirl port TBI heads. They make decent low end power.

It was rumored that you could tell a 4 bolt motor via the drilled oil gallery plug behind/above the timing chain area. The hole at about 11 oclock above the timing chain area is what I'm talking about. It held true with my old motor, but my new production Vortec 4 bolt motor is not drilled/tapped/plugged there.

sucp_0907_32_z+chevy_350_engine_value_pack+timing_chain.jpg


I purchased some sort of thermal barrier to try on the inside of the topper to try and keep condensation down, but have not applied it yet. :(
 
all the same, the tow package etc had nothing to do with the engines, no mystery really. most likely a 2 bolt engine unless a later 91, or a replacement block could be a 4blt
 
I edited the last entry, but the 10 min. limit got me. I type s l o w l y.

The 6 mpg was because the motor was weak and I put new tires with alot of tread/weight and it made it change from drive to over drive too often unless I was on level ground. I ran it in drive so it wouldn't kill the trans. The trans worked good when it was parked.

I don't know why it was weak. The oil was changed religiously at 3K by my wife. We used Castrol GTX and it was the only one that got weak at such a low mileage. It started leaking from the valve covers 2 times that I remember, maybe more. The oil return holes in the heads were clogging. The holes seemed small if I remember right. When I parked it, I think it still idled at 20 to 30 pounds and had about 40 pounds of pressure running at around 2500 rpm's. That was with the oem gauge.

That's all that I can think of right now.

Thanks, Paul
 
I know that the double hump heads are from long ago, I was just using them for reference. I think everybody that has messed with a SBC knows about the double hump heads. Some of what I found is that it could have 1 of 3 different head castings, 191, 193, or 810. I'm guessing that they are referring to the last numbers in the part numbers.

I also saw where it said that the engine could be a 350L130 or another one like 350L150, not sure of this number.

Paul
 
DYEager 535, the thermal barrier that you bought, is it a thin stick on sheet type of material? If so, that would work under my headliner. I'd really like to find a spray on, where I can paint over it. It seems that I've heard of a spray on heat shield that is being used in NASCAR. I'm trying to keep it as original looking as possible. That's why I'd like to find a spray on that can be painted.

Thanks, Paul
 
Yes, when you see "193" or whatever, they are referring to the last portion of the casting number. Not sure about heads, but casting numbers don't always match the part number. I suspect with heads they do.

The heat barrier stuff I got is a spray on product. Mascoat DeltaT is what it was called when I purchased it, google search shows Mascoat Marine-DTM, I assume it's either a successor, or re-branded of the same. http://www.mascoat.com/marine-insulating-paint.html
 
Is it going to be smooth enough to paint over? On the shell it's not very important unless it's real rough, inside might be different. I've got to repaint the metal part of the top too. I wonder if that stuff would be smooth enough to put auto paint over and look right? It would have to help keep this thing cool. If the A/C wasn't on for 20 or 30 minutes the inside never really got cool (no rear air back then,I don't think).

Would I be OK to put my VIN number on here? I don't know of any problems but who knows. Most people won't put a gun's s/n out. I've never heard of a problem because of that either.
 
I don't understand the issue posting S/N or VIN some people have. The ones you have to worry about, the ones who keep getting hacked, already have your address, birthday, and every serial number and VIN you've ever purchased.

Not sure what you can do grabbing a VIN online that I can't do by getting it out of the windshield in a parking lot.

The guy who sold me the thermal stuff was interested in hearing how it worked for me. He wouldn't guarantee it, I was the one that wanted to try it, but he thought it might be helpful. I don't understand if you want it inside or out, but since the top is rough textured inside and out, not sure why it would matter.
 
Your VIN isn't going to narrow down casting numbers or any of that. Build specs on your truck will be pretty generic and underwhelming stuff. Options are obvious, same with transmission type. That leaves gear ratio as about the only unknown. 99% of these left the factory with the G80 box checked, so almost all got the Gov Lock in the rear diff. Most definite way to check gear ratios is the remove the covers, clean with brake kleen and check the numbers stamped on the edge of the ring gear.

My '90 was a low option rig, came with 235/75 tires and 3.08 gears with the 700R-4. 3.42's are also common, especially if your truck left the dealer rolling on 31-10.5 tires.
 
Deager535, I live in S.C. and if it the insulator sprays on fairly smooth up to the roughness of the fiberglass then I can spray both inside and out and paint the outside and inside if necessary to make it look right. If I get the thin sheet stuff I can use it behind the headliner, maybe even spray it before I apply the sheet and reinstall the headliner. In the middle of our summer you can feel the heat radiating off of the roof over your head on a sunny day and it would help the AC keep up then, otherwise it can't unless you are running 60 mph.

tRusty, I'm still trying to get accustomed to the way things are done now. Like I said earlier, back then if you got a vehicle with a factory towing pkg. you really had something. Most systems on the vehicle, especially if it was a truck/RV with the pkg. were affected. I've got to get used to it.

According to the window sticker it has 3.42 gears. The sticker also says quote "H.D. Trailering Special Equip......$407.00", "LockingDifferential-Rear Axle......$252.00","Rear Axle 3.42 Ratio.....$38.00", "Heavy Duty Front Springs....$62.00","Front Quad Shocks.....$100.00. I guess that the hitch costs $407.00.

I didn't know IF there was a potential problem regarding the VIN. The VIN is 1GKEV18K0LF5502709. That's a good point about getting it in a parking lot.

I hope that this helps you understand why I'm asking these questions. I guess that I'm just disappointed that a towing package doesn't mean anything anymore. If it was like it used to be, it sure would have helped me with some of the things that I want on it eventually. Oh well, you can't win them all.

I do appreciate the responses and help, Paul
 
I wouldn't feel too put out, the things you want, or might want, or don't know you want yet are all readily available, easy to install, and relatively cheap. These rigs are so easy to work on, and customize to suit yourself...

So, your front springs should be three leafs, rather than the standard two spring pack.

The quad shock option is a throwback to a time when shock technology was suspect at best. The two shocks initially installed by GM would have been lightly valved, the idea being that two shocks would take twice as long to overheat and stop damping properly. The problem is once the OE shocks wore out regular shocks were installed which made the truck ride like a tank. The best thing to do if you have dual shock up front is remove one shock from each side, and maybe consider upgrading to a single quality monotube like a Bilstein 5100 series.
 
Thanks tRusty, I haven't had any ride problems so far, it still has the original shocks on it. Believe it or not they seemed fine when it was parked. Infact a buddy of mine had commented that it rode so much better than the others that he had ridden in. They aren't leaking and the front isn't bouncing, it settles right down. I'm going to leave them alone for a while and do other things like get the mtr. rebuilt. I figure when I need to replace them that I'll get some adjustable ones, maybe 4 instead of 2 if I can get some that can be adjusted like these were. I guess that way that they should last a long time too. As far as the engine I'm thinking about getting a company to do a mild custom build. It's been so long since I built one that I don't trust myself and all it takes is one mistake to spend alot more money. I'm thinking about getting it built like a low to mid rpm torque motor without going over board. I'm thinking a motor like they used in the old vans that were for custom conversions and maybe just a little more cam. I do love to hear one that has a beat.

Thanks again, Paul
 
You must log in or register to reply here.

Latest Posts

Top Bottom