engine gurus, help!: engine rust on top of 4G64 block, how bad is it?

**peanotation** · 01-30-2009, 01:00 AM

when i got it back from the machine shop, the tech told me to keep it constantly wet with LPS oil to prevent rust. over the years i've let it slip my mind every once in a while and now i have this:

i'm sure it could be sanded/planed when i finally build it up, but i imagine compression will rise significantly....how bad is this?

**mko** · 01-30-2009, 01:10 AM

I aint no guru, but the rust where the headgasket is should make no difference if you wetsand it with 800. its on the edges and not around the cylinders or water and oil passages. That should do the trick for the water pump and oil pan as well.

What you got there? .20 over?

**Galant306m** · 01-30-2009, 01:40 AM

i would just stone it off, find your self a nice bench stone, most hardware stores will have them, get a nice round one with fine and course grit. While you are getting that pick up some tapping oil, put the oil on the stone and in a circular motion stone the block with the fine grit ONLY. Make sure that you go in a circular motion though and do not press down to hard. The oil is just used to aid in clearing the grit.

i can't find a picture of one but ill take a picture of one at work and post it when i get home so you can see what im talking about. you can get a cheap one for like 20 bucks and they last along time. To clean it cause it will build up with rust and small bits of metal just spray it down with some break clean and whip it off with a rag.

**Cali** · 01-30-2009, 02:55 AM

when it doubt take it to the machine shop.

doesn't look too bad though.

**Stewi** · 01-30-2009, 05:51 AM

yeah not too bad. Peano, after you clean that biatch up. Get some oil on the bare metal surfaces and vacuum bag the block. Get a big ass vacuum bag from walmart, the ones they sell for clothing storage. Put the shortblock in there, vacuum seal it and store it. Those vacuum bags work very well.

**seth98esT** · 01-30-2009, 07:43 AM

I dont think its bad at all. Just take it to a machine shop and have them clean it up.

**PharmEcis** · 01-30-2009, 10:17 AM

Originally Posted by Galant306m

i would just stone it off, find your self a nice bench stone, most hardware stores will have them, get a nice round one with fine and course grit. While you are getting that pick up some tapping oil, put the oil on the stone and in a circular motion stone the block with the fine grit ONLY. Make sure that you go in a circular motion though and do not press down to hard. The oil is just used to aid in clearing the grit.

i can't find a picture of one but ill take a picture of one at work and post it when i get home so you can see what im talking about. you can get a cheap one for like 20 bucks and they last along time. To clean it cause it will build up with rust and small bits of metal just spray it down with some break clean and whip it off with a rag.

Please stop!

NEVER EVER EVER EVER use a stone on a deck surface! Are you Fing crazy?

Depending on the suface, you need a finish of RA20 or better for a proper seal.

The rust on the bottom of the block is insignificant. Don't worry about. That is going to get sealed by sealant and an oil pan anyways. The front of the block isn't that bad either but clean it up w/ some 600 grit if you want.

You should really have the block deck. You can still see the composite gasket remains on it's surface. The trick there is to use a fine green abrasive pad for the first pass. Use WD40 and try to get the majority of crap off. After that move to a 600 grit piece of sand paper, again wet w/ WD40.

If you are going to use a metal headgasket, you need to take that thing back to the machine shop and have it decked. Plain and simple.

**ZigenScarface** · 01-30-2009, 11:48 AM

power wash it with battery acid should do the trick

**Galant306m** · 01-30-2009, 12:19 PM

Originally Posted by PharmEcis

Please stop!

NEVER EVER EVER EVER use a stone on a deck surface! Are you Fing crazy?

Depending on the suface, you need a finish of RA20 or better for a proper seal.

The rust on the bottom of the block is insignificant. Don't worry about. That is going to get sealed by sealant and an oil pan anyways. The front of the block isn't that bad either but clean it up w/ some 600 grit if you want.

You should really have the block deck. You can still see the composite gasket remains on it's surface. The trick there is to use a fine green abrasive pad for the first pass. Use WD40 and try to get the majority of crap off. After that move to a 600 grit piece of sand paper, again wet w/ WD40.

If you are going to use a metal headgasket, you need to take that thing back to the machine shop and have it decked. Plain and simple.

lol yea the stones that we use are higher then 600 grit.

**seth98esT** · 01-30-2009, 12:28 PM

What he is trying to say is that you shouldnt sand the top deck or any surface that has to be within tight specifications. That should be left to a machineshop who have proper tools who can make sure the tolerances are even across the entire deck.

**xd_01** · 01-30-2009, 12:39 PM

i have the same problem but my motor has only sat around for like 6 months since it left the machine shop. it has a light coating on the deck that i was thinking i can lightly buff out but it also has some at the top of a couple of cylinder walls. very upsetting though so i know how you feel peano. i shouldve torque down the head down as soon as i got it. leason learned though.

the smartest thing to do would be to return to the machine shop with it to see what the machinist says which is most lilely what im gonna do.

and the vacuum bag is a great idea but it will only work with the motor off the stand. i tried it on the stand and taped the hell out of any spot i thought air might get in and it never worked. its gotta be off the stand.

here are my pics