Rebuilding a Buick 350 - need some tips

Stock FSJ Tech Area
Post Reply

Topic author
Philip Parker
Posts: 10
Joined: Mon Mar 05, 2018 6:11 pm

Rebuilding a Buick 350 - need some tips

Post by Philip Parker »

Howdy - I've got the heads pulled from a buick 350 and the bottom end still in the truck. I'm about to start throwing stuff back together and need some tips on a few items:

1. Thermostat temperature rating. I've read 160 is the way to go. Looks like a stock radiator so I am assuming it is a 2 core.
2. Cylinder #8 had a stuck exhaust valve. Should I replace this valve or clean it up and see if it will fit the journal without too much resistance?
3. Should I reuse the valve springs, hats and shims?
4. Is it worth it to upgrad the oil pick to the later 5/8 tube style?
5. The engine is getting new lifters, push rods and a mild cam upgrade, anything else I'm missing that I should do now? Rear main seal?
6. ????

Thanks for the tips everyone.

Herk
Posts: 274
Joined: Mon Mar 25, 2013 8:14 pm
Location: Boise

Re: Rebuilding a Buick 350 - need some tips

Post by Herk »

Beware commonly available replacement pistons. Most "engine kits" come with late 231 V-6 pistons which will give you about a 7.8:1 compression ratio. The 5/8 pickup is worth it, so long as you drill out the block passages. The TA Performance cam bearings are a good idea. The correct thermostat is a 195. Make sure to use the Robershaw high flow type.
User avatar

tgreese
Posts: 7118
Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Rebuilding a Buick 350 - need some tips

Post by tgreese »

Regarding the exhaust valve, I would clean up the stem and see how the fit is. You can get a general idea of the fit in the guide using the wiggle test. Any idea why it stuck? The condition of the valve face and seat is essential here. Being stuck open could have attacked the seal between face and seat. The valve face can be machined ("ground") to provide a new sealing surface, as long as the edge of the valve does not become too thin once a suitable condition has been achieved. Condition of the seat is equally important.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

Topic author
Philip Parker
Posts: 10
Joined: Mon Mar 05, 2018 6:11 pm

Re: Rebuilding a Buick 350 - need some tips

Post by Philip Parker »

tgreese wrote:Regarding the exhaust valve, I would clean up the stem and see how the fit is. You can get a general idea of the fit in the guide using the wiggle test. Any idea why it stuck? The condition of the valve face and seat is essential here. Being stuck open could have attacked the seal between face and seat. The valve face can be machined ("ground") to provide a new sealing surface, as long as the edge of the valve does not become too thin once a suitable condition has been achieved. Condition of the seat is equally important.
The valve was actually stuck shut. The seat looks ok as does the face, I have not tried to thread it through the guide yet. I hav noticed a few other valves have a tiny bit of play. I'm talking miniscule though. Is that an issue?

440sixpack
Posts: 332
Joined: Sun Jul 31, 2016 6:31 am

Re: Rebuilding a Buick 350 - need some tips

Post by 440sixpack »

If you're just trying to make it run you might get away with it. but if you're rebuilding it the heads need to go in for service. I assume like most engines of the era you'll need hard seats and your guides are probably shot if it has any miles. but a very minor amount of movement is ok but the guides have to be measured.

You're not rebuilding the short block ?

Topic author
Philip Parker
Posts: 10
Joined: Mon Mar 05, 2018 6:11 pm

Re: Rebuilding a Buick 350 - need some tips

Post by Philip Parker »

440sixpack wrote:If you're just trying to make it run you might get away with it. but if you're rebuilding it the heads need to go in for service. I assume like most engines of the era you'll need hard seats and your guides are probably shot if it has any miles. but a very minor amount of movement is ok but the guides have to be measured.

You're not rebuilding the short block ?
Trying not to touch the rotating assembly. It turns beautifully by hand and rings have held light oil for a couple weeks now as I've had it opened it. New timing gears and chain, lifters, rods, cam, water pump., oil pump, and every gasket I can get to in the process. The bottom end was spotless when I pulled the oil pan. Valve guides have minimal to no play.

There is only 21k on the odo. I've been trying to figure out if it is 121k or just 21k. So far it looks like every gasket is original. Pedals have minimal wear. Steering and brakes are fantastic. Frame looks spotless other than patina. I think it's original 21k. The truck sat for 28 years apparently.

440sixpack
Posts: 332
Joined: Sun Jul 31, 2016 6:31 am

Re: Rebuilding a Buick 350 - need some tips

Post by 440sixpack »

Turning over real easy might just mean it's pretty worn out. how much ridge is there at the top of the bore ?

Maybe you're right and you're going to get away with it. that would be great ,but I'd check it out as well as you can it's cheaper and easier to fix it the first time.

Topic author
Philip Parker
Posts: 10
Joined: Mon Mar 05, 2018 6:11 pm

Re: Rebuilding a Buick 350 - need some tips

Post by Philip Parker »

440sixpack wrote:Turning over real easy might just mean it's pretty worn out. how much ridge is there at the top of the bore ?

Maybe you're right and you're going to get away with it. that would be great ,but I'd check it out as well as you can it's cheaper and easier to fix it the first time.
The ridges are about as thin as a piece of paper - almost like its just carbon deposit. I was under the motor staring at the crank and rod caps all day - what else should I be checking for?
User avatar

swampedge
Posts: 341
Joined: Mon Jun 11, 2012 5:21 pm
Location: Melbourne,Fl.

Re: Rebuilding a Buick 350 - need some tips

Post by swampedge »

Once you’ve installed your valves push them open with a wooden dowel or hammer handle to the full open position if possible and release them to see that you have free movement.


Sent from my iPhone using Tapatalk
You really are judged by the dogs you have!
Post Reply