isosceles

I made a stupid mistake during my motor swap. With the L48 already back in the car, I started it up and notice a coolant leak. Sure enough I left a plug out of the LT cylinder head when I moved the temp sender to the manifold. I grabbed the plug from the 383 and tried to install it between the headers, under my wire looms.
Well, the plug disappeared into the hole in the side of the head. In my fatigue I didn't notice that the plug was much smaller. I tried to retrieve it with a magnet, but it must be way down in there. I did find the appropriate sized plug and sealed it up. I added coolant and ran the car while setting the timing and adjusting the idle speed. The temp stayed at 180 (180 stat in the car).

My question is, how far down does that water jacket go and should I bother pulling the head of worry about getting it out? It was a chrome plated steel plug with an allen socket in the middle, about the size of a nickel.

VETDRMS

It would have to be fairly small to make its way into the block, but it "could" lodge itself somewhere and restrict flow.
90% chance you'll be OK, but it would bug me enough to try and retrieve it. Seeing how you already ran it for some time with it in there, that could be quite the task.

GDaina

wonder if a flexible magnet would find the part...

platato

I'm going to vote the other way. I give it a 90% chance of causing big problems. Any obstruction is a bad thing in the block. We tend to run a little hot anyway and restricting flow at all just adds to the problem. I would be very worried that it eventualy travels and shuts down waterflow permanently or combines with some rust and other debris and does likewise. I know it's a big bummer to go fetch it but I'd hate to see a couple dollar part trapped in the block cause you $4000.00 worth of damage, a tow, an accident or to have you or your Vette stranded in a dangerous area. If the block is original I would worry even more. In any event, I'm sorry for your situation and I definitely feel your pain

STW!

Platato

P.S. Make sure the plug isn't chrome covered brass if you try the magnet

VETDRMS

If I remember correctly you have iron heads... This is going to make using a magnet a bit difficult.

StickShiftCorvette

While it is best to get the plug out, I would bet that you would NEVER be able to see any change in running temperature.

Even if you could instrument the block with thermocouples I bet that you would not be able to find a measurable local hot spot.

There is not much heat generated at the bottom of the waterjackets and a small plug wouldn't restrict the flow much in any event. It it were tight against the cylinder side of the wall it might act like a fin conducting heat away from the source and if were to the outside it would increase the localized flow velocity which could aid in heat transfer to at least partially make up for the reduced flow volume.

VETDRMS

Wait a second... you took the 383 out? Why?

isosceles

Yup. saving it for a race car. once the 383 was in, my wife couldn't drive the car anymore, gas mileage got REALLY bad, and I can't use the power on the street. Here's the details of my decision.

http://forums.corvetteforum.com/show...5&forum_id=119

cardo0

Water flows up and out the heads. Yea, most of the wtr holes from head to block are smaller than what a 3/8" npt plug? And with coolant flow up towards the intake and out throught the thermostat i bet it either ends up stuck in the T-stat or hangs out just behind it. Hey after u run her a bit drain some coolant and pop the T-stat for a lookie.
Slow down man, ur making me tired just reading 'bout it. cardo0

page62

Sounds like a good excuse to do a head swap on the L48. ("Honey, I gotta pull the heads to get that plug. And while I'm at it I might as well install decent heads." Do a cam swap too, if you don't have a decent one in there already. If you use small intake runner heads (like the Summit cheapies I used), it will make the engine MORE streetable than it currently is (IMHO)

isosceles

Cardo: good suggestion about the T-stat. I think there is a 180 degree stat in there now and I'll change it to 160. Hmm, that gives me an idea: I wonder if I pull the water pump off and stick a high pressure garden hose in the left side port if it would force the plug up? I don't know the routing of the water jackets.

I'm not terribly worried about it, but it bugs me knowing that thing is in there. Yup Cardo0, it's about 3/8" thick, completely round on the outside because of the allen head socket in the middle.

Page:
Your car runs THAT much better with the Summit heads? I have a Comp Magnum 270H in it. I'll probably see what kind of numbers I turn at the track. If the car is consistent, I'll leave it alone. Part of the reason for the motor re-swap was MPG. My thinking is that the low flow heads will provide better MPG. Or is my theory wrong because other heads would provide a more efficient burn?

page62

The stock heads are nothing but junk. And yes, heads with Vortec-style combustion chambers provide a more efficient burn and more HP. I'm definitely getting better MPG. In terms of power, my SOTP estimate would be about 35 HP. (Plus 5 HP for the Summit decals, of course!)

isosceles

I already have some of those! I have 2 decals: how many do I need for the 5 ponies? how bout 10?

Seriously, I agree about the stock heads being junk. As time and money allow I might do the upgrade. As long as I don't mess up the consistency for bracket racing. For some reason, traction was never an issue, even with the 383. Could be the lousy gear and low stall converter.

Are you running stock compression? I don't remember if it's different for an L82.

page62

Original compression was 8.9:1 in the L82, and is about 9.5:1 with the new heads. Went from 76cc chambers to 67cc. The specs on these heads are identical to old "fuelie" heads, with the 2.02/1.60 valves. Of course these heads have modern touches, like improved flow in the runners and Vortec-style combustion chambers...

wills670

where did you try to put the plug in the side of the block. the only place i know of you can put a plug in is the head. i do not remember any other passages other than the one that is at the bottom of the block to drain the block and the heads. if you tryed to place it in the head it should not have went very far and should be fairly easy to retrive with a magnet as long as it was not brass as someone else said.
if that is the case you could pull the head and retrive it. it probaly wont go very far from the hole. other than the fact of knowing it is there it probaly wont cause any problems.

isosceles

Wills,
it was in the head, between #1 and #3.

I might try a flexible magnet like Gdania suggested. Maybe if I use some electrical tap around the sides of it I can target the plug. especially if it can't get below the bottom of the head.

I was SO careful while installing the 383, I didn't pull any boneheaded moves like this. I also wasn't in as big of a hurry, I'm trying to make the Corvette Challenge this coming Saturday.

wills670

the best i can remember you only have two passages on each end of the head/block were a fairly large plug could get access to the block.
i dont think it will end up in the bottom of the block. you might try a mirror to try to see the plug and then try to remove it. if you cant get it with a magnet and can see it with a mirror try to dry it off with brakekleen and then try to get it to stick to some bubble gum or something else that is sticky.

isosceles

OOooOOO, like expansion valve wrap tape! Was wondering what I was going to do witha whole roll of it.

I also picked up a flexible retriever with the 3 claws that pop out and a magnet.

norvalwilhelm

I can't see it making one bit of a difference. It will fall to the bottom some where and remain there. Some blocks are filled partly with a filler anyway and still are streetable.
I wouldn't loose sleep over it. It won't cause any heating problems and the chances of it making it's way into the water pump and next to nil.

Slick McFavorite

I don't know all the details and can't picture where the plug is hiding but would there be any chance of flushing it out with high pressure water?