: head gaskets on a 351M,


IDK
05-20-2005, 12:05 PM
I am basicly a noob when it comes to rebuilding engines, I bought a 351M with about 80K on it, I got it on a engine stand so i can rotate it 360 degrees around, it sat for about 8 years, i got the intake, vavle covers, oilpan, and all the pullys and belts, water pump, dist, all elecronics, and, basicly its the block, & heads. The engine is realy cleen everywhere internally, no gunk in the engine pan, under the valve covers or pretty much anywhere. Its got a elderbrok 4 barrel manifold, and i am getting a 600 or 650 elderbrok carb wit a manuel choke.

heres my questions, do i gotta take all the valves and springs out or can i just leave that intack and take the heads off in one piece, i figured i would take a shoebox and poke holes in it so i can draw a diagram on top of it so i dont mix up the rods, Do i have to get the heads resurfaced or only if they are realy bad, i aint building a huge HP engine here, just a mildly built stock engine.

It would be great if someone could help me out a little

2. one more quick question, THere is a bearing on the back of the engine where the flywheel bolts too. THe bearing is shot. How would i go about replacing this bearing, i am hoping that i dont have to tear down the whole engine comletly, Anyone know how to change this bearing,

THanks a lot in advance.

Also how much work does it take to replace the cam and put a more aggressive one in.

3. Is there a way to figure out if the engine is in time when i still have it on the stand, I want to get it pretty much done when i go to stick it in the truck. THanks a lot

The truck is a shortbed f-150 4x4 79

ImNotRight
05-20-2005, 04:25 PM
You do not have to completely dissasemble the head to change the HG. However these engines are known for having bad valve guides and/or seals, so if you are going to be freshing the engine, it doesn't make any sense to skip it.

Best bet is just let a shop check them out and do it. It's not worth the effort if you don't already own the tools.

Yes keep the pushrods in order if you are re-using them. Along with the rocker arms.

If you are talking about the pilot bearing, it's easy to change. The pilot bearing is inside of the end of the crankshaft, and it's be around a 1" diameter needle type bearing.

I have always used a little slide hammer meant for yanking them out, but I've been told you can just pack grease behind the bearing and shove something in the hole to force it out.

To change the cam you just need to take the lifters out, the front cover, the oil pan(I think? too much time with chevy's, i forget exactly how the M block is put together), and obviously the timing chain. Line up the dots on the crank and the cam sprockets, and yank. Throw in your new cam and timing chain, make sure the dots line up according to whatever brand's directions, and put it back together.

Line up the dizzy to #1 (whever you put it), drop in the dizzy, do the wires... etc.

IDK
05-22-2005, 01:09 PM
so i pretty much just unbolt the head bolts and it should come right off or am i missing something, then just keep the pushrods in order,

i never did a head gasket change on anything befor. So any tips would be helpfull.

There is no gunk or sledge in the engine so i think it was well maintained,

jopes
05-22-2005, 01:34 PM
remove the rocker arms, that way you can pull out the push rods, keep the rods and rocker arms together and out them back in the same posistions. Unbolt head and pull off. the m block rockers are torque to spec. no adjustments needed.

You should not need to drop the oil pan to change out the cam, but if the pan is leaking now is the best time to replace that as well.

IDK
05-23-2005, 11:07 AM
thanks, i am redoing all the gaskets, oil pan, valve covers, intake, and head gaskets. keep in mind i never did engine work befor but am very mechanicly inclined, will the rocker arms be under any pressure or in other words will they shoot off and fly away or no, i figureed i could keep turning the crank wit a wrench to keep the rockers in the up position when i remove them, i am gunna need a spring compressor when i put it back together, right?

thanks a lot jopes,

you are on fullsizebronco.com right, your name sounds firmilar,

thanks a lot again.

jopes
05-23-2005, 11:09 AM
I get around on a few sites.

just loosen the rocker arm bolts. they will not go flying.

mj
05-23-2005, 11:41 AM
jopes is a bit of a forum slut, like most of us

IDK
05-23-2005, 01:57 PM
i got both of em off in about 20 minutes each, took my time to make sure i didnt snap any of the bolts,

1 out of 16 of the push rods( i think thats what there called) was snapped right at the top,

would it be a problem if i took on from another 351M i had and just substituted it in, or do i have to replace all 16,

also the cylender walls are not scratched at all, but the tops of the pistons are covered wit carbon, i think its carbon, what can i used to clean all of this off. i was thinkin just brake cleaner or engine degreaser, but i wanted to check befor i do something stupid,

the headgaskets are kind of stuck on, one on the head and the oposite side is stuck on the block, what is the easiest way to clean them up and take off the gasket, i dont want to mar up the surfaces.

Once you have the engine stripped down, and turn the crank wit a wrench, its pretty cool how it works, i dont know why i am amazed by that but i thought it was pretty cool,

thanks

i didnt check the surfaces for true flatness yet, i want to get the gaskets off then check everything.

jopes
05-23-2005, 03:16 PM
easiest way is some gasket remover. permatex makes the stuff. spray it on it will eat up the gaskets and scrap off with a razor blade. if you have 1 bad push rod just replace it with the same length rod. I used to have some stock lenght pushrods but I beleive when I built my engine I tossed them all in the garbage because I am running hardened rods now.

If you think the engine has over heated and the heads might be a little out, just get them machined. it is not that much money.

IDK
05-24-2005, 11:01 AM
thanks, i got a seize 351M, that i can get a rod out of, i am just gunna check it for straightness to make sure it aint bent, I am gunna stop at pepboys on my way to work to pick up gasket remover for the head gaskets,

brake cleaner should be alright to clean the piston tops wit, just double checking thanks a lot