Head Gasket on 429 - If it were put on upside down, what would happen?

[William R Conte]

My newly rebuilt engine got hot immediately on first run. Did this 3 out of 3 tries, blew hose off first two times. It fails compression test badly.

My question it this... Can the head gasket go on upside down? If so, what would the result be?

[William R Conte]

lower hose on pump was first. Upper hose from radiator was second. I thought I hadn't tightened them sufficiently. When I ran it today I made sure there were no air pockets, and the radiator tanks got hot right away, and this thing was stone cold since Wed night when i started it. Three cylinders under 100. The other five ranged 117 to 170. I'd just about bet the ranch it's head gaskets. I'll know fairly soon. Local guy rebuilt it. It was smooth as glass when it was running. It has 14 1/2 minutes of run in time on it at over 2000 RPM the whole time. I've done this sever times with my Camaro and this never happened. Even checking the shop manual, I didn't do anything wrong.

[William R Conte]

I'm going to pull the heads off.

[William R Conte]

It isn't. The oil looks fine, and the level did not rise. When I pulled the valve covers off, there was no trace of water visible.

[24ro8f5mbs2jc]

The compression is a bit worrying. Was it a complete rebuild, or just heads and gaskets? You can always do a pressure test of each cylinder (cylinder leak down test) to get an idea.

Regarding the temp, have you tried turning the engine without the thermostat to see how the coolant flows and also removing air bubbles? I would take an old thermostat and remove the thermostat part and only use the outer ring fitted in the gasket to get a proper seal with free flow of coolant. You could try this test with spark-plugs out and let the starter just run the engine a few minutes to get an idea if the water pump is functioning properly. If you really want to observe the coolant flow use an open bucket, 1-2 feet above the engine, and connect the cooling system to it (suction from bottom of bucket and return over the top). If done properly you could, with another bucket and a stop watch, calculate actual flow of coolant.

[William R Conte]

It was a complete rebuild, top to bottom. It got an overbore by .020 and new pistons, rings etc. Standard size bearings. Rebuilt rocker shafts. All the usual items. I'm looking forward to getting the heads off.

[Jason Edge]

Regarding the high temperature, did you go back with an original temp sending unit, or known good one? The new aftermarket ones are crap and are miscalibrated and will show HOT on the instrument panel temp gauge. I always use an IR temp gun and point to head right next to the temp sending unit. These are 20 bucks or so and will give you an exact reading and is good insurance.

It takes some time for the rings to wear in but having done that your compression seems way off. I would guess compression rings not installed correctly or perhaps incorrect. It is the oil ring that I found finicky and second guessing when I rebuilt mine. The compression rings seemd pretty straight forward. There is a top and bottom side to them.. not sure what would happen if you install upside down. On the head gaskets I don't recall top side or bottom side but you need to use your eyeballs and grey matter upstairs to ensure the holes all align in gasket to engine. It would be pretty careless of your rebuilder not to do that. and of course torque things down correctly.

Let us know what you find out ... and make sure you have a good temp sending unit and/or temp gun. 

[William R Conte]

Original sender. Glad you mentioned the temp gun. I'm going to pick one up. Looking at photos, the gasket appears to be symmetrical from side to side, except for one hole. From the location of that hole, I suspect that it is the oil supply hole to the rocker shafts. The hole in the block is directly in line with the main oil gallery at the rear of the block. The rocker shafts are getting oil, so the gaskets were in right. The shop manual does specify that the top of the gasket says TOP, and that they must go in that way. I really suspect it had an air pocket, I missed it, and that ultimately caused pressure in the water jackets that took out the gaskets. I'm anxious to find out if I'm right.

[3rhxwymkupkp8]

How about a stuck thermostat or air bubble?  Maybe remove t-stat and test.

[William R Conte]

I had tested the thermostat in a pan of heated water and accurate electric thermometer, and it was working. I only had it in the first two runs.

Removed it on the last run. Tank on radiator was getting really hot in about two minutes. Water was circulating on startup. Started really gurgling hard and puking water out. I suspect air bubble first time I ran it on Wed, and blew head gaskets at that time.

[William R Conte]

The water pump is a rebuilt original. It's working fine. I saw the water circulating on the last start, and even during the compression check, so that isn't it.

I pulled the pass side head off. No obvious big blowouts, but the metal around the lower outboard water ports in the head is all dark, much darker than the rest of it, and it goes right up to where the sealing ring for the cylinder is. There are no cracks that I was able to see with a strong LED work light. Cylinders look perfect.

I still have to pull the driver side head off. If appearances are the same on that side, or if there is just an obviously blown gasket, I am going to obtain the necessary gaskets, etc and put it back together. Oil looked as expected for break in oil. I already have another six pack of break in oil on the way here. Lucas break in oil 30 weight.

I'll oil the cylinders before I put the heads back, and run another compression check, and see if it comes back up, before starting it again.

[William R Conte]

The closer I'm looking at the parts, the more I feel it's a head gasket issue. It won't take much to cause this, especially if it's in several spots.

Yes, this break in oil is expressly for this purpose. It's what the machinist gave me for it.

[William R Conte]

Holes in heads, gaskets, and block are not a 100% one for one match. Strange, but I guess that's how they are. I just got all of my gaskets, thermostat, and oil filters here yesterday afternoon. I also painted the radiator support, so I will be putting that back in before I attempt to run it again. I had to get a new heater control valve too.

It's going to be 82 deg here in NJ today, so I am taking my motorcycle out for a bit. After that, I'll go back to the Caddy. My plan is to clean head and block mating surfaces by hand with lacquer thinner and scotch brite pads, wipe and oil the cylinders, and put the heads, water pipe, and oil filter back on, and give it a fresh oil fill with the fresh Lucas break in oil, 30 weight, as it had in it before. From there, I'll do a quick compression check to make sure that compression comes back up where it should be.