Cylinder Height?

[muff]

The other day my 440 blew a head gasket and when i took off the top end i noticed that the top of the clyinder is below the top of the head, its 10 thousanths of an inch to be exact, is this ok to have it lower or does it need to be flush?

i can get it machined for like $40 so its not really a big deal to get it done i'm just not sure if i need to do it or not

any help is appreciated

[Castor-426ex]

how thick is your head gasket??

and when you had the 440 done did they deck it??

[muff]

i didnt get it done the guy i bought it from did, he said it costed around $600, i dont know what else he did

i just got a new cometic gasket, its stainless steel and its 3 plates, i didnt know what kind of thinkness i should have so i didnt specify one when i ordered it

so when you say deck it does that mean make the head flush with the top of the cylinder?

thanks for the quick reply

[muff]

bump

does anyone know what decking the cylinder means?

I know I am starting to sound like I get a comission or something but, check out an old thread" have you decked the cylinder" do a search its a great thread and will answer all your questions.

BTW no you dont want it down into the hole at all, but be sure your at TDC on the comp stroke.

I hear from FST that their new pistons are mfg'd to correct this problem also, but check with them.

Good luck

[muff]

ok thanks a lot, i forgot about checking that thread, i'll go measure the piston clearance sometime today

[muff]

bump, i need help

if i put the piston at tdc andif its at or below the top of the cylinder i can have the head machined so it'll be flush with the top of the cylinder right?

obviously if the piston goes all the way to the top of the head i wouldnt have it machined

[MIKE400EX]

Before you start machining, you need to do some checking. What piston do you have in there (brand & number on top)? What base and head gaskets are in there now and what are you going to use (thk. wise)? Has the head been modified in any way? Finally, what compression ratio are you wanting to have? Oh, and be careful with the dowel pins when you lift the jug up, they like to fall out!

[muff]

its got a JE 10.5:1 piston and i think its an ims sleeve but i'm gonna call the guy i bought it from and find out some more info and i also need to find out about the base gasket thickness, i just ordered a steel head gasket from cometic and i didnt specify what thickness so i guess its the stock thickness, i want to be able to run pump gas so under 11:1 i guess
there isnt a number on the top of the piston i just checked
and the head hasnt been modified to my knowlege but i'll need to ask him that also

and thanks for the advise on the pins

i'm gonna call him in a little bit and find out the answers to these questions

[MIKE400EX]

Cometic sells a composite head gasket which will seal better. It's a little thicker so order the thin cometic base gasket, or use sealer to make up the difference. You shouldn't have to do any "decking" with that IMS/J&E piston. The composite head gasket WILL have to be re-torqued after you break it in. What cam do you have in there?

[muff]

its got the stock cam in there

it just seems like it shouldnt have the top of the sleeve .010" lower than the top of the head

Cometic sells a composite head gasket which will seal better So thats where the oil is leaking from :) I have the steel 3 piece .025 (on the third one now) and the current one does leak a little more than I am happy with, I am hopefull that the new one will be better when I freshen it up later next month.


You shouldn't have to do any "decking" with that IMS/J&E piston. Mike if you remember my old posts I have that same set up and it is still .005 in the jug with .015 shaved off the cyl and cometic .012 base and .025 head gaskets.

So take you measurements and pick your machine shop carefully.


its got the stock cam in there
If you want all this too work your gonna need to change the cam.


it just seems like it shouldnt have the top of the sleeve .010" lower than the top of the head
Do you mean that the top of the sleeve is .010 lower than the top face of the cylinder or .010 above the face of the cylinder?

Before the machining the sleeve in mine was slightly higher than the flat face of the cyl. its now flush since the decking.

[muff]

Originally posted by 440EX4me

If you want all this too work your gonna need to change the cam.


Do you mean that the top of the sleeve is .010 lower than the top face of the cylinder or .010 above the face of the cylinder?
[/B]

the sleeve is .010 lower than the top face of the engine block, i'm going to have it machined down this week so it'll be flat

what gaskets do you think i should run, i've already got the stock thickness steel head gasket, but what base gasket should i use and what thickness?

thanks for the help

i would really like to buy a cam but i dont have the money right now, what will happen if i dont?

[MIKE400EX]

Your cylinder & sleeve were probably machined flush before,, but the sleeve wasn't seated correctly in the cylinder. Now that it has been "used" a while the sleeve has seated and left that .010" gap, which is probably why the gasket went. Have it machined flush, do not take any more off than necessary to clean. Slap a cometic base gasket on there, and if you were not having any pre-ignition problems put the steel shim head gasket back in.
BTW, w/o changing the cam you're hardly making a difference over stock, the extra compression is the only thing helping. The stock cam will not hurt anything more than the performance.

[quadman21]

Mike, you give good advice. I wish I had known that you have to re-torque the composite head gasket. I had one and really liked it but it started to leak oil after a month. I went and bought a steel head gasket and freshened my 440 witha a hone and new rings. I tell ya guys...the things you learn a day late and a dollar short!

[muff]

yeah thanks a lot mike you've helped me out a ton, now what thickness base gasket should i get? should i get the normal kind or stainless steel (if possible)

thanks again

[MIKE400EX]

Cometic makes a coated paper type base gasket, I think it's about .012" thk., that works well. You don't want a steel shim base gasket - if they are even available. You do not need any sealer between there when using a gashet - but if you have to, don't plug up the small oil hole (it feeds the top end). Also don't forget to put the o-ring back in no matter which gasket you use.
While you're in there, is that a flat top piston? How far is the top of the piston down in the jug? Just curious!

[quadman21]

What happens if you don't put that o-ring back? I left mine off because I just assumed the 440 sleeve was larger and it wouldn't fit.

[MIKE400EX]

It's meant to keep oil from getting between the cylinder and sleeve, and seal the internal pumping pressures(from the piston going up and down and combustion bypass).

[muff]

its a flat top piston, i'm not sure how far down it is but it's a little bit below the top of the sleeve

back to the cams, are the hotcams stage 1 and stage 2 any good? There's some for $130 on ebay with no trade in of the stock cam, whats the difference between the two, i'm gonna mostly be doing some mid speed trails and a little motocross

thanks

its a flat top piston, i'm not sure how far down it is but it's a little bit below the top of the sleeve

This is where the problems with the 440 begin. The sleeve in the 440 kit in mine had seemed to seat higher in the cyl. (about .004) and is fluch since the decking.

Try to see if you can get a accurate measurement of how far down in the cyl that piston is at TDC. If you do you will save yourself some trouble and cash if you get it decked the correct amount the first time, or you could save the cash and loose some performance due to the reduced compression.

Just post the measurements and you will get the info from one of us.


I have had no problems with the .012 cometic base gasket so if you need to get the piston up a little higher go with it.


Both of the hot cams are good but are also not the most aggressive and will not perform the same as the larger cams available. There is also a decent diff from stage1 to 2.

What I have seen the stage1 (which is not to the specs advertised, so be carefull since its a little larger than the XR etc) will not give the same top end as the stage2 but will give you a smoother powerband and less low end loss. I think that from what you have said you would be happy with either.