Background is that I had the engine and transmission out of my 80 F100. The truck had sat since 1997 and did not run quite right. Never done anything to this degree mechanically on a vehicle before and I wanted to learn and tear into the engine (302).

I cleaned up the heads. Went ahead and replaced the intake valves since a few were pitted more than I'd like. Lapped all the valves. Checked for leaks by submerging them in water and shooting compressed air in the exhaust/intake ports. All checked out fine. I did not remove the pistons, but I did clean up the cylinder bores and block surface. New head gaskets, new oil pan gasket. New thermostat and new water pump since what I had was quite corroded and nasty looking. I had the timing chain cover off to inspect the timing chain which looked fine. Replaced all the gaskets and front main seal. I replaced all the pushrods since I noticed a few of mine were bent. I did go ahead and replace the lifters while I was there. I went with a new intake manifold Edelbrock 2121 and Edelbrock carb to compliment it over my stock manifold/carb. Replaced the intake manifold gaskets, of course. It took me longer to do all this than it should've as I was taking my time to read and learn what I could. I mainly wanted to do it right the first time and not have issues once the engine was back in. Well, there are issues.

I got the engine & trans back in last weekend and spent free time during the week reconnecting it all. New radiator, heater core, hoses since mine were leaky. Filled the rad with water, checked my engine oil level, filled the trans, power steering. Engine fired right up. Sounds fine. I'm watching for leaks and have a laser thermometer gun I'm watching the temps. Notice some oil leaks at the back of both valve covers. I did clean up the valve covers well and used new gaskets, torqued to spec prior to this all. There's also trans fluid with a steady drip between engine and trans under the flexplate. Continue waiting for it to come up to operating temp so I can dial in the timing and carb. I don't get that far because the coolant overflow starts to boil. Water began to pour out of overflow and between the engine and transmission.

I am devastated that after all my careful work something went wrong this quickly. I did a compression test on all the cylinders, and they all were at 150 PSI. I did a leak down test with 90 PSI in each cylinder:

#4: 76 #8: Did not test. Tired, getting dark, frustrated.
#3: 80 #7: Piston kept dropping & engine turned over after multiple tries? I'm 100 % sure I was TDC on compression stroke.
#2: 78 #6: 70
#1: 70 #5: 70

My compression test seems fine, right? Leak down test seems awful from what I've read. I had the rad cap off during this and did not see any air bubbles.

I'm at a loss right now what my next step should be. Do I pull the engine and trans again? There was that small leak of trans fluid I'm concerned about, but I have bigger issues. Maybe the front seal got disturbed....? It wasn't leaking before, so I did not touch anything on the trans. There wasn't any liquid in the cylinders. I haven't checked the oil to see if water made it in there. I think I'm at least pulling the intake manifold off. But with my leak down test, I'm looking at the heads, too. May as well take the whole damn thing out and look to see where I went wrong.

 

Ooff, sorry to hear all that. I'll be watching this thread close because the same procedures may be in my near future. Just curious, how long did you have it all apart for?

 

Did you check the heads and block for flatness? You said you replaced lifters but not the cam? If you put new lifters on a used flat tappet cam, you will wipe out the cam lobes, and the lifters, in no time. Did you find a reason you had bent push rods?

 

For a few months, Memorial Day weekend.

I did with a machinist straight edge using the smallest feeler gauge. Not able to fit feeler gauge under it any after various orientations. It is a flat tappet with hydraulic lifters. All that I've seen says you can use new lifters on an old cam but not the other way around. I'm assuming the push rod was bent due to the engine sitting 25ish years causing a stuck lifter/valve. One of the reasons I wanted to go ahead and just replace all the lifters. The rocker arms and valve springs checked out to be in spec. The engine was overhauled a year before it was parked up for other reasons so I went into it fairly confident most of the parts would be alright.

I'm coming to the conclusion I just pull it all out and see if I can figure out where I went wrong. It goes in and out easy enough.

 

Correct.

To replace both is ideal........but new lifters onto a good used camshaft is accepted practice.

 

Do not worry about the coolant overflow after your first coolant fill and run. They all do it. You have air trapped in the engine. If you want to minimize this, take a coolant sensor out of the manifold or take one of the hoses off the heater core at the engine. Fill the radiator till you get coolant running out of the sensor hole or the small hose port. Then quickly plug the hole with the hose or the sensor. You will still get this problem, but it will be much less. Some of the foreign cars have their act together, and actually have a petcock on the top of the engine somewhere to bleed the air out as you are filling.

On the trans leak, did you replace the front seal in the transmission?

On the front seal oil leak. Did the harmonic balancer have any sort of groove where the old seal was running?

 

I get that they overflow with air trapped in the engine, but to flow out somewhere between the trans and engine? I did not replace the front seal in the trans. Front seal for the engine is not leaking.

 

I always drill a 1/8" hole in the flat of the stat to let air by.

Rent or buy a cooling system pressure tester to find where this other leak may be.
I cant see pulling the motor just for a coolant leak. And if it is at the rear of the block, is there a freeze plug back there??
You may need to drop the trans for the front seal leak so do it then.

Old cam & new lifters you need to do a cam / lifter break in or you will wipe them out in a vary short time.

Front seal on the trans may seal in a bit with a little running. If not you will need to drop the tran to replace it.
Dave ----

 

I went ahead and pulled the engine & trans out in a couple hours this morning. I'm glad that I did because when separating the two the front seal of the trans was definitely leaking. Rear main on the block has evidence of motor oil. That's new, I didn't replace the seal previously because it wasn't leaking to start with. Trans has issues. Dark red, almost black, fluid -- I had just put fresh fluid in. Metal shavings in the pan. I'm sure the linkage falling down in to gear the way that it was did it no favors.

I got the engine back on the stand, connected the radiator to it, and filled with water. The cooling system tester I picked up didn't have the right fitting for the cap so I ditched it. I set my air compressor outlet to 10 PSI and pressurized the system through the overflow. I did not observe any leaking water or hear air anywhere. Downside of the way I pressurized is I couldn't monitor for leaks with a gauge. Freeze plug on the back of the block was intact as were the cylinder head freeze plugs. It was a serious waterfall of water yesterday between the trans/block. I'm still puzzled where it came from. It's nothing to pull the intake and heads off at this point, which I'll do sometime this week for a closer look.

The new Edelbrock intake that I put on did not have the rear water passages like my cylinder heads do. The gasket I put on matched the cylinder head so there was a rectangular opening for a water passage that is now non-existence. I wonder if water somehow pushed past that?

 

If you think the intake was leaking and is not now and the way you had water & air hooked up drain the oil to see if water went into the lifter valley and into the pan. If nothing I would not pull the intake.

If you only have 1 freeze plug at the rear it is for the cam not water.
Also some intakes are not wet, was your old one wet (water went thru?)

On the trans if the fluid went dark fast you may want to get it rebuilt.
Dave ----

 

I'm going to check it out this evening. I was not entirely sure if my block had wet intakes so I went ahead and put ARP PTFE Sealer on the lower head bolts for insurance. I do plan to send the trans out for a rebuild at this point.

Since I had new lifters on an old cam I think I need to do a break in? The engine ran ~10 minutes, maybe, at 1000 RPM idling. Break in is 20 minutes at 2000-2500 RPM? Are the new lifters and old cam toast at this point or should I be alright?

 

It would have been nice to have the RPM up to the 2000 - 2500 for that 10 min but what is done is done.
When you get it running again run it at the 2000 - 2500 for a full 20 min again and fingers crossed all will be ok.
Were you running a high zinc oil and zinc additive when you first started it? If not add the zinc at next start up.

A bunch of us got together for a buddies first start on a rebuilt motor, more eyes the better as he was also running a new transmission and EFI system.
He had a trans ATF leak at the add on cooler in front of the radiator.
But the big thing was he was not running a fan, felt someone may get bit by it
Well even with a 3' fan right in front of the radiator it over heated and had to shut down as she blew water all over!
We had lunch and let it cool down, added the fan and finished the break in.
Last I hear it is still running but only has maybe 300 miles on it. He is having issues with the belt drive system he made.

For you and him only time will tell
Dave ----

 

Rotella T4 10W-30 is what I ran. I did leave the fan shroud off for easier access to things. Next time I'll put it on to help direct air flow and put a big shop fan in front.

 

I would still add a bottle of zinc to the oil just to be safe.
Think Lucas Oil is who I got the last time I needed it for the race car.
https://www.lucasoil.com/product/eng...-oil-additive/
Dave ----

 

Thermostat verified installed correctly. Placed in a pot of 180F water and it opened, as expected. I didn't realize before but it has a small bypass for coolant prior to it opening. I did NOT drill a small 1/8" hole on the top to help with air bleeding. I will when reinstalling.

Intake and head gaskets intact. No evidence of what would've let the water waterfall at the back of the block. The freeze plugs are all here. No water in the oil pan or cylinders. My lower cylinder head bolts are confirmed to be wet & thread through the water jacket. I sealed them with ARP PTFE Sealer upon installation. I'm not sure if water found its way out of there? Should I just go ahead and replace my freeze plugs?

Question on the piston faces, see pics. They were nice and clean, engine ran ~10 min. Is what I'm looking at to be expected here? I didn't get a chance to dial in the carb so it's possible it was running rich and this is fuel that didn't detonate. Some areas of it felt sticky. Other parts suspiciously like oil. Could my piston rings need replacing?