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.

350 TBI intake gaskets, nasty engine!

eodcoduto

eodcoduto

We could have been closer.
 Premium
Joined
Jan 4, 2011
Posts
1,550
Reaction score
1,503
Location
Muscle Shoals, AL
IMG_0533.jpegIMG_0534.jpegI’m doing the gaskets on the suburban and this thing is nasty. It burns/leaks about a quart of oil once a month and with the EGR completely plugged up I’m hoping it runs better once everything’s buttoned up. It gets 1000-1500 miles a month put on it so it needs to hold out until next year when the LS swap happens.
 
Pretty nasty. Maybe some marvel mystery oil, and some budget oil with a few warm ups and dump.
 
Last edited:
The engine in my Blazer looked worse than that. The push rods were going through tunnels of sludge! The drain back holes in the heads were almost completely plugged. I drained the oil, and left the drain plug out and rinsed the lifter galley, and heads with about two gallons of solvent. I put it back together with fresh oil, and ran it until it warmed up. I changed the oil, ran it for a week, and changed the oil again. The same engine has been in my Blazer for 15 years! Still runs great!
 
It will get the old Kersosene douche once its cleaned out. Rural king had a sale on Rotella the other day so I grabed 20 gallons, going to use some this weekend.
 
Is this from coolant getting into the oil or what? I'd be paranoid of something getting blocked from the galley or the whole mess blocking the pickup or filter as cleaning it. I'd probably pay more attention to the oil pressure gauge than the road. Of course you can always starve one bearing while still having pressure, in case you've been sleeping too peacefully at night.
 
The oil pressure on it is great 35 at idle warm, but it was seeping coolant and oil outside the engine. The gaskets are toast and the exhaust crossovers have been cooking oil. I can’t run any worse when its done!
 
6 hours later. Thats a mix of old Valvoline 10/30 and Drags Specialties straight 60wt from the Shovelhead. Kerosene worked as it always does. So its time for gaskets and then I’ll drain the pan and fill it up.
IMG_0537.jpeg
 
old school and works trick is 1qrt ATF basic stuff nothing fancy and non-friction modifier stuff with oil change ( sub 1 qrt oil ) .

drive 500 miles and change oil and filter .

do this until oil is clean on change compared to starting .

ATF has the most detergents and is a 5w based oil . i have done it a few times and great results . and the guy who showed me also used it many times and have great results .

pulled valve cover on a old ford 2.9v6 motor i had and it was nasty . 3rd oil change like this you could eat off the cover and head it was so clean .
 
Its all back together and after a 20 mile test drive nothing is leaking. It seems a little smoother but its idling high, I reset the IAC but its still high so I’ll give it a few days to adjust on its own.
After this weekend I’m debating selling this thing and getting something pre-1975. All the crap you have to remove and mess with for simple repairs on this thing isn’t worth it. I’d like to find the GM engineers in charge and repeatedly kick them in the nards.
 
I wouldn't sell it, keep at it, besides after all that effort you just put into it, don't want you to get a case of sellers remorse.
Buying something pre 75 for as easy as it sounds, think of all the inherent potential issues.
Although you never mentioned what year your rig is, maybe some of that crap you can live without, unless you have smog requirements.
Plenty of us have been in your shoes, but after the headaches with some of the required wrenching, they are still a blast to drive.
 
Its a 91 so there are alot of pros, but that also means it has alot more parts in general that go bad, engine and interior. Its probably not going anywhere for a while but the engine swap is getting pushed to the front burner now.
 
No I’m keeping the tbi, it runs like a new vehicle now, is smoother and doesn’t downshift on a couple of hills on the way to work. With the 4l80e a carb swap would be more expensive than its worth for fewer gains.
I’ll drive it like a tbi 350 and not try to make it run like something else until this engine dies, then something different will go in.
 
83ChevyK5Blazer said:
Just gut the emission's and swap to a carb with a fp regulator. I blocked off all the emmisions on my 91 and still ran the tbi for years.
Click to expand...
I've basically done this on a TBI 350 I pulled from a rig and swapped into my '65 GMC. I put a four barrel intake on it and a Holley 600 CFM carb. I kept the heads and cam in place.

It's been a real pain getting a carb tune on it, especially as a Holley carb learning exercise (also high elevation at 7000ft).

What I've found is that even a Holley 600 is too much carb for these motors. I think since they tend to flow really well at low RPM, and not so well above 3000 RPM, I've had to jet the primaries fatter (stock 64, where they say I should be at 62 for my elevation) and use a much smaller PVCR than stock to get this setup to not get a rich bog above 3000 RPM. Getting into secondaries is even worse -- I'm jetting those down to 58 (probably even leaner on the next tune).

I'm doing this all with an AFR and vac gauge in the cab -- just trying to get it close enough until I can get a more traditional iron head and cam setup for a mild 350.
 
You must log in or register to reply here.

Latest Posts

Top Bottom