Hi Everyone; I finally got my 350 together and started up. The problem i'm having is it's overheating. I'll run it for around 3-5 Min. when cold and then my temp goes up past 230. This happens even without the thermostat in. I took my time filling the Rad to make sure the block was full and the water was coming out of the by-pass hose. I put the water neck on and filled it the rest of the way. Took quite a bit. Everything was tightened up so I started it again, same thing. The heater hoses are getting hot so I know it's pumping but it still overheats. The rad hoses are hot too. I'm using Poston's .02 steel shim gaskets and have them on right. (I'm quite sure). Are they supposed to be punched for the other cooling passages or the other holes there just for the core sand knock out. The long slots on the back of the block match up with the gasket to the head, so it seems as tho I should have good return flow back through the head. Can anyone help? I'm lost. My 300 had the cooling system this way so I thought the 350 would be the same. HELP!! PONCH
Can you see water/ antifreeze flowing when the pressure cap is off (make sure to remove when engine is still cold)? Is your temp gauge accurate? If you run it without the pressure cap it will be boiling like mad at 230*, if it isn't boiling then probably the gauge is faulty.
Hi Marc, Thank's for the reply. I can see water flowing pretty well. I just took off the drivers side head and the cylindres are dry as opposed to the passenger side. I figure there must be some kind of obstruction. I duct taped, (The Pro Grade Stuff :laugh: ) water holes on the passenger side and slowly poured water in the rad. The drivers side finally started getting water. The car is sitting level too. I'm gonna keep poking around to see what I can find. I think both of us have a few Months before some nice cruising Weather sets in. So There's time to do some digging. Again, thank's for the reply and i'll let you know what I find. PONCH:beers2: Bo Beer
I can not open the pics on this computer, however I think I have a few things that may help. 1. You were using a 72 350 I think from what I remember, and if so the steel shim gaskets are only for the 68-71 engines. If you use the steel shims on a 72-80 engine you will have cooling issues, many have run into this before. 2. Some of the 72 engines had scallops for extra cooling and some did not so if you were mixing and matching heads then read the thread in my sticky above called "head swapping". If you post your head casting numbers that will help as well. info about the casting numbers here:
Hi Sean, Thank's for the info. Here's what I have. Heads are B-1238145. Dates are, J-15 which has scallops on both, and H-30 which has a scallop on one end and round on the other. Both are 72 Heads. The block is a 72 with 4 scallops. What would be the problem with opening up the closed sections of the gasket. They just dump into the water jackets. Or maybe just the One on the end. This is what I feared when I read that a 350 swap was "Just about a simple drop in". It hasn't been too bad really, but the little BS is a pain. Like getting the long exhaust manifold bolts in. But thanks again and I hope you can make out the pics. PONCH
Ok I can see the pics now. I dug up this quote from when Hector tried to add the steel shim gaskets to his 79 enigne which is the same configuration as yours with the center passages: BTW, I prefer the fel-pro gaskets anyways over the steel shim since they are more forgiving. Especially if the block and headfs are not machined flat before install. I know you have are not rebuilding so there is no reason to machine other than for gasket surface quality... Bottom line, I would use fel pro gaskets and go have some fun! And, just to clearify one more time for everyone: If you use a late 72-80 block you can use ANY year heads and if the heads have scallops you need the fell pro type gaskets, if the heads have no scallops you can use the steel shims. If you use the early block without scallops you can only use the heads without the scallops unless you block the holes inthe heads with a copper chunk or something. If you use the late heads on an early engine without blocking the holes then even if you use the late gasket you will still have coolant leak to crankcase due to the gasket not beeing enough to hold the pressure.
By scallops, I'm guessing you guys mean the big more or less round coolant holes? On the overheating Ponch, the first thing I'd do is make sure your gage is accurate. One of those harbour freight $40 infra-red temp sensors is a good tool and will let you see where it's hot and where it's not. That just might pinpoint your problem. Make darned sure you don't have retarded timing, that'll heat 'er up like nobody's business. So will steam pockets in the heads. Just a couple of things to watch for. Jim
Hi Jim; The First thing that told me I had an overheating problem was the Temp gauge running up to,230. The Second thing was the water neck hose blowing off and steam and water belching out of the water neck all over the back of my gagage. That gave me a pretty good clue right there. The hose clamp wasn't on very tight. I'm just glad me or no-one else was in front of the engine. Thank's for the feed back. PONCH
Yeah those are a couple of good clues. You don't usually pressurize the system much until you get close to boiling. Well now, about steam pockets. If those start to develop then you get hot spots and make more steam so it gets out of hand pretty quick and it sounds like that could be happening, since the only other obvious thing that occurs to me is a compression leak into the water jacket and you haven't mentioned anything to suggest that. Normally that would pressurize the coolant system, blow out antifreeze, lower the coolant level and then cause hot spots or steam pockets. (Or was that hot pockets? You got Hot Pockets in your water Jacket? :error OK, so obviously first make sure there isn't something about your combination of block, heads and gaskets that allows steam pockets to form. You could try drilling a 1/8" hole through the gasket at each of the scallops to vent any steam build up, that wouldn't allow enough water flow to bypass normal circulation. Your circulation is all the way back through the block and then all the way forward through the head (and perhaps the intake, but this can be restricted or blocked off by the intake gasket). Be careful not to short circuit this pattern too much, though I'd be inclined to block off the rear water ports to the intake if you don't need much carb heat. Might affect your heater output though, depending on how it's plumbed in. Jim
did you put the gasket on upside down ? did you use a sealant on the gasket gasaginch is what ta recommends for shim type head gaskets
I wonder if you couldn't open a hole in the gasket to correspond to the holes in the head and block. It looks like the gaskets are embossed around those areas so should seal???
how long have you been running the new motor ? in my experience most fresh motors have tendency to heat up good .... usually lasts 10-20 minutes ..garden hose in the neck of radiator and no thermostat ....and if you have ...a few fans in front of radiator.
If you think nothing is wrong one of them flush n fill kits can be helpful. You can then hook a hose up into the heater core line feeding fresh cold water into the system. Should help burb it and suck if you think its just not filling right.
This doesn't appear to be a cooling issue. It's something to do with the head gasket no letting coolant flow through the heads.I think he said one of his heads was dry when he pulled it off.
Well Thank's for all the ideas guy's. I'm still waiting for the new steelies from Postons. No, the gaskets weren't upside down or backwards. The UP on the gasket actually was UP. The little holes in the gaskets on the scallops are 3/16". So the One closest to the front of the engine i'll make 1/4". The back One will be around 1/2" or 7/16". The one under the long slot on the block was completely covered, so i'll make that one the same size as the hole on the head. The hole under the front slot will remain covered. I guess i'm just used to my iron 300. Too simple. But I keep hearing about how 350 Heads are all the same,,,BUT,,,,!? I'll get the engine running tho. I'm no dummy. It ran great for about 5 Min. and sounded Mean. I'll get there. I'll keep everyone up to date and here are a few more pic's. Thank's agaun!!:beers2: Boh. Ponch
Ponch, I wonder if there's not something else going on here. Like when I got my 340 block back there was a freeze plug inside the water jacket. No way I'd have known, but it rattled when I turned it over on the engine stand. If you have one side dry there's a reason for it. That reason is most likely your problem, not the size of the steam bleeds in the head gaskets. If they're there already they don't need to be made any bigger, that will just mess up your normal circulation. All they are there for is to let vapors escape and there isn't going to be that much. (doesn't take much) Is it possible you could have some sort of a blockage at the water pump discharge hole on that side? Odds are pretty fair it's going to be some oddball thing like that. Jim
Hi Jim; I plan on removing the water pump and looking at the routing. There's nothing in the way on the intake. I have it off and looked it over. I took one of the old head gaskets and messed with it. I put some holes in different area's just to get an idea of the routing. The bottom hole in the gasket was covered all the way under the long slot in back. I cut that one 3/4". The one on top was 3/16" and I made it 5/8". The top hole was covered too. It look's a lot better now. With just the back slot open, I can see where there would be a problem. I'm still waiting on my new gaskets. I'll let you know. PONCH
