420A Changing the head

[JakewittheGS]

So I bought my first dsm vehicle in December of 2020 and so far it’s been great. Up until a few weeks ago that is. When I bought the car it had a radiator leak and a valve cover leak. Upon further inspection(really out of curiosity as to why the car never overheated with a leaking radiator) I discovered it didn’t have a thermostat. To cut the story down a little bit, i soon began to leak oil at a decent rate 1-2 quarts in a few hours after parked. Put the car on a lift and degreased the engine bay and underneath and found a crack in the head. It never lifted the head and I have yet to see any sign of moisture in the oil so the plan is to just change the head. I guess my main question would be where to start looking for the parts to do this and what all should I change? I know I’m getting new head studs and the full upper gasket kit but is there anything else that’s a necessity to change if I’m staying stock for right now? Also before the engine is started the timing is being checked since these are interference engines

 

[VelocitàPaola]

Along with the gaskets and head studs, you might want to consider a new timing belt, tensioner and water pump, depending on how old those components are.

Your car is losing 1-2 quarts of oil while it's parked (i.e. engine is off)? Am I reading that correctly? If your cylinder head has a crack in it, then by all means, replace it; but I wouldn't expect you to lose so much oil through the head with the engine off. The first place I'd look in that scenario is the oil pan.

 

[BLACK'98DSM]

Get a head from the junkyard and have a machine shop fix it up for you. Throw in some new valve stem seals. Make sure you use the cam caps that belong with the head, they are specific. If they look worn, give them to the machine shop and they can add material and line bore them. Give them your cams too and they can polish them.

Nobody makes new head for the 420a. Some sites sell re-manufactured heads, which basically meas they're junkyard heads that have been vat dipped and resurfaced.

Go with an MLS headgasket. FelPro makes a good one. There's no need to get it over-sized. The machine shops usually only mill 0.010" off the head and that's nowhere near enough to throw anything off.

And if you have the extra money, I'd recommend throwing in a set of PT lifters while you're in there. They will keep your fresh top end lubricated well.

 

[JakewittheGS]

I’d leak it after the car was cut off.. like right now it’s sitting and it hasn’t leaked since the last time it was driven. I’ve already gone through and checked the oil pan and other things I thought could be the cause before we degreased and physically saw it leaking from the head. I have paperwork from the timing belt being changed ~20k ago

Along with the gaskets and head studs, you might want to consider a new timing belt, tensioner and water pump, depending on how old those components are.

Your car is losing 1-2 quarts of oil while it's parked (i.e. engine is off)? Am I reading that correctly? If your cylinder head has a crack in it, then by all means, replace it; but I wouldn't expect you to lose so much oil through the head with the engine off. The first place I'd look in that scenario is the oil pan.

 

[JakewittheGS]

Get a head from the junkyard and have a machine shop fix it up for you. Throw in some new valve stem seals. Make sure you use the cam caps that belong with the head, they are specific. If they look worn, give them to the machine shop and they can add material and line bore them. Give them your cams too and they can polish them.

Nobody makes new head for the 420a. Some sites sell re-manufactured heads, which basically meas they're junkyard heads that have been vat dipped and resurfaced.

Go with an MLS headgasket. FelPro makes a good one. There's no need to get it over-sized. The machine shops usually only mill 0.010" off the head and that's nowhere near enough to throw anything off.

And if you have the extra money, I'd recommend throwing in a set of PT lifters while you're in there. They will keep your fresh top end lubricated well.

I found a reman head after not being able to find an eclipse in the junkyard near me so im gonna go that route

 

[VelocitàPaola]

I’d leak it after the car was cut off.. like right now it’s sitting and it hasn’t leaked since the last time it was driven. I’ve already gone through and checked the oil pan and other things I thought could be the cause before we degreased and physically saw it leaking from the head. I have paperwork from the timing belt being changed ~20k ago

Gotcha. Sounds like you have a good handle on the problem then. If you already have a remanufactured head, you should be good to go after you get the head studs, head gasket, and upper gasket kit.