Pulled My Intake, Found Some Odd Things

I pulled the intake manifold off of the 88 350 that I am putting in my 51 Chevy. I found some things that I need some info on.

1. There is a broken manifold bolt. I assume that penetrating oil and an easy out is my best bet to remove it. But its odd that its broken since all the other bolts came out REAL easy.

2. There was alot of white powder inside only 1 of the intake ports. It looked like the white powder that builds up on battery terminals. What is this?

3. There were block off plates in 3 of the water jacket ports. WHY? The ports behing them are MUCH rustier than the others.

Here are some pics:

 

White powder in the intake valley, maybe your engine had a previous life as a drug mule car.

 

Mercury marine...........? Would explain funky water jackets and restricting flow.

 

Nope, the motor came from a running 88 Chevy Suburban. My buddy drove it to his house and pulled the motor. Its only been a few months.

And it turns out that what I thought was a broken bolt was a rubber plug that was inserted into the hole. It seems like a factory thing...

 

The white stuff could be corrosion from the aluminum intake manifold. I would bet the restrictors were to maintain coolant flow or guarantee warm/hot water to the heater core or cores, Suburbans could have 2.

 

The center ports are not water ports, they're heat risers for the intake manifold, I blocked them off in my SBC's I've ran. Only really need them in cold climates for automatic chokes.

 

what he said^. done the same on the few chevys i have run.

 

These block off plates were on the rear 2 ports and 1 of the front. Originally it was a TPI motor. I wonder if maybe the TBI liked more heat.

 

Late Model Junk

 

I thought they were only on the back ob OT stuff. Dont remember seeing any on front. If you block off the center you fuel stays a little colder.

 

The block off plates at the rear are there to force coolant flow thru the intake manifold to heat the incoming mixture on TBI engines. Your heater line runs to the rear of the original intake, correct?
The front I can't remember...but if it comes blocked off in your new gasket kit I'd leave it there.

Your reusing the TBI it seems?
If not...the manifold supplier should put you on the correct path as to what their intake requires.

 

I am switching to a GM aluminum intake for a carb. Its the one that only a Q-jet works with.

 

What are those heads? Center bolt covers but have the old intake bolt pattern? Pre-Vortec?

 

Ya pre vortec. 88 Suburban.

 

That engine has been "into" by someone in the past.
I think the block is set up for a roller lifter cam as the casting nubs are in the valley for the lifter retainers. Wasn't a roller cam stock in 1988?
Where did you find the rubber plug? Was it in the head in the last bolt hole in the one closeup picture of the head?

 

The plug was in the passenger side front most hole in the head, where the intake bolts on.

 

The rubber plug is definitely not factory,probably threads screwed by previous work and it doesn"t look like your buddy did many oil changes ,if the top of the engine is that gummed up have you pulled the pan to check the bottem end out.?

 

its wierd, I checked the threads, there the plug was and they were fine. I haven't pulled the pan yet, but I plan too.

 

In 1988 roller cams were not standard equipment they could have been built with or without, your block is machined for one though. The block off plates should be in the rear coolant passages and are usually made in a factory gasket they are for coolant restriction and they should have a small hole in them the front passages should NOT be blocked at all the center ports are exhaust ports and can be blocked off with no consequence to the engine. The two center intake bolts are at a different angle than a factory q-jet manifold you can slot the holes in your intake and make a wedge shaped washer to fix that or buy an aftermarket manifold I have done the wedge washer deal many times and never had a lick of trouble. As far as the plug was in in the same hole as the broken bolt if so it could just have been silicone. Those motors are notorious for rotten intake manifolds and broken bolts as a result of electrolysis. Just my experiance from wrenchin on this stuff everday for 20 years

 

Cool thanks. The Q-jet manifold I have bolted right up. It had the center bolts that are at an angle.

 

G'day, In 1988, only the 350's in the Camaro and Corvette came with roller cams although most of the blocks had the casting for the spider and the lifter bores were spot-faced for the lifter retainers. I've had 350 truck engines apart as new as 94 and all were flat tappet. With the blocks already machined it is easy enough to remedy.

ms

 

good to know. Thanks

 

I'd also be worried about the amount of gunk inside the engine - has it had regular oil changes or has it had the guts run out of it. The amount of grud and grwasy build up in the valley area of the photos suggests it has been run ong periods without regukar oil changes or has been run on non detergent oils
IT NEES A CLEAN OUT

 

Whats the best way to clean it out?

 

im sorry but that thing screams flood engine to me, did ya carfax the 'burban?


i could be wrong.

 

I dont think it ever got wet, but I guess you never know. It was running about 3 months ago when we pulled it.

 

Whats the best way to clean it out - strip it down and scrub it clean - there are some additives that may clean it out however if stripping the engine is not an option then i would wash out what i can see, leave the drain plug out as you do it and flush the sump as best as possible - I have used kerosene or white spirits in the past and you do get a reasonable standard of cleaning. I'd then run diesel engine oil in it with regular oil and filter changes for a time then revert back to your regular good quality petrol engine oil. The diesel oil has a cleaning property in it that helps keep a diesel engine clean - even though you would not think so at the balckness of the oil however it does work