I just bought an engine that is supposed to have just a burned valve in # 7 , hopefully that is the case. I took some shots of it, does this look like it is what it is supposed to be? Thanks.


PS, this is an engine from a 95 GMC truck, TBI 350

 

2 The edge of the valve (dark area) is just a bit of oil.

 

3

 

1 and 3 slugs

 

5 and 7 slugs

 

.

 

Any help by just looking at these photos?

I have yet to remove the other head, most likely tomorrow. 1 and 3 look to have been run lean, but on a TBI , how is that possible?

 

Thank you all for any help you may have!!

 

I would say the engine has been ingesting coolant, possibly from a failed head gasket or another gasket upstream. Does the throttle body get heated by coolant on TBI?

What do the spark plugs look like, do they have the white deposits on them from holes 1&3?

The clean looking combustion chambers say to me that it had a head gasket failure or something to let coolant into the cylinders.

 

not all the cylinders on one side opf the engine are fed by one injector. Each injector feeds cylinders on both sides of the engine because of the way the intake is set up. If its lean, id say the flowrates of the injectors are mismatched. In order for your engine to appear to run at stoich to the computer, some of the cyl on the good injector will ahve to run rich to compensate for the lean cyl.

 

it does look like a head gasket has been letting coolant in.

 

I just thought I'd point out that no it doesn't look like coolant was leaking into the engine. I can't see a burned exhaust valve, but I can tell that 1 and 3 were lean, 5 looks good, and I'm not exactly sure what to make of 7. I think my heads looked like # 7 when I got them though, so I wouldn't make much of it. It looks like there is some ash in 5 and a little in 1 that could have been burning oil.

I don't see a burned valve. I almost thought #7 intake looked like it had collided slightly with the piston and the edge got bit off, but that's oil smeared on it?

 

if you had a burnt valve you'd know it as soon as you saw it, you wouldn't be asking here. the edge of the valve is missing, literally burn off just like it was cut with a torch.

 

I don't see a burned valve, which would look like it had a chunk missing out of it; or any coolant. I do however see a fair amount of oil burning. And, as usual, the head gasket is blown between #3 & #5, and #5 & #7 too. Contrast how clean and non-brown it looks between #1 & #3, against the place between #3 & #5 especially. Looks to me like the heads were over-torqued.

It does not look like it was running particularly lean to me.

Why are we doing this? Was there something wrong with the motor, or what? Or are you just refreshing it as a matter of course (like I would)?

 

See the dark area? Thats where the gasket was blown. The fire ring should always be shiny metal, any darkness or black spots is a leak.

 

Yeah, you've got valve issues. You may have been sucking coolant, too, or sharing it between #5 and #7. It really doesn't matter anyway, since all of those weenie little valves should come out of there and get replaced with some decent sized parts. The seats will get cleaned up nicely when they are cut for the new valves, and the bowl porting should clean up any deeper damage. The first thing to do is to disassemble, clean, and inspect the heads. A hot tanking and Magnaflux at your favorite machine shop might be worth the cost. Don't worry about losing the springs, retainers, and valves. You probably won't want them anyway.

Dished pistons? You're probably thinking about new samples there, too. The PM rods might be worth saving if they are intact. And if the case is prepped for a roller lifter setup, your window of opportunity is wide open. Make the best of it.

 

Thanks guys... I only know that the motor came from a truck with higher mileage. This engine came from a local GMC dealership. I need to put a motor in one of my cars and thought if it only had a bad valve, I could slap on some differant heads and go about business. Looks like that may not be the simple solution.

 

Are these heads worth putting money into? They are just the standard TBI 350 heads... I have a set of heads from my buddies IROC that I planned to use.

 

I think what you've got there is a good 350 shortblock core and two good bass boat anchors.

Go through the block completely (pistons, rings, bearings, cam, timing set, oil pump), and have the deck shaved slightly to get it nice & flat. Use the heads from your buddy's 350, doing to them what Vader suggested (along with new springs and screw-in studs). People seemed to have missed the swirl-port implications.

 

it looks like you blew a head gasket, thats why 2 cylknders valves are clean looking and the others look normal. i might be wrong, just a sugestion, if so get the block decked and bored then rebuild it. if you dont want ill take it.

 

I don't see any evidence of coolant leakage into a cylinder. Usually, if there's a cyl <-> water jacket exchange going on, there will be a huge smear of brown or black combustion products around the water jacket in question, because combustion is so much higher pressure than water; and of course the stainless steel ring around the cyl will show combustion leakage the same way. In other words, alot more combustion will leak out of the cyl, than water will leak in. I don't see that.

The heads look to me like crappy 76cc bathtub chamber smog heads, somewhat like 993s. They are trash. The pistons are dished garbage. Also trash. If you tear this thing down, you need a set of decent heads, and a set of flat-top pistons, when you put it back together. If the heads are TBI heads, then they're trash of a different sort, but trash just the same.

Like five7 said, looks like you've got a good 350 core block, maybe a good core 350 cast crank and set of rods, and a whole bunch of garbage other than that.

 

Ok, here is the other side...2,4,6, and 8

 

8 and 6

 

4 and 2

 

..

 

slugs close up 4 and 2

 

8 and 6.

 

the even cylenders look pritty good, but those are defanitly smog heads and low compression(7:1 or 8:1)dished pistons. if it's from a Heavy duty truck it could be a 4 bolt block and could have a steel crank, I have yet to see a truck block that dosen't at least have 4 bolt mains. definatly pull the pan and take a look.

 

Thanks for the help guys...