I have my short block all done and mocked up the cylinders/pistons again to measure up my deck height so I could order some cylinder shims.. I had the cylinder registers decked.. I believe the machinist said he took off .008". I'm running a 80mm crank..
Anywways so I rotated the crank and the pistons sit proud of the cylinders by .052" not under the cylinder deck.. above it.. This is with the cylinder base gasket on.
Now I'm going to be picking up stuff to measure the cc's of my heads, but since they're stock 2.0L heads with I believe just bigger exhaust valves I put into the CB perfomance CR calculator 55cc's... just for messing around tonight... If I wanted to get 9:1 compresssion, I'd need a .146" spacer.

Obviously the numbers I have are just rough until I CC the heads, but my question is this .. Is there even spacers/shims available in that sort of thickness ?????? If so, where ?
Thanks a bunch

Rimco or European Motor Works.

They're available in that sort of thickness ?! Learn something new every day...

Look closely at your heads....there's a "step cut" or ridge that the edge of the cylinder sits on and it's actually raised from the actual "deck" surface that the combustion chamber is carved out of. You'll need to measure that step and deduct your .052" measurement to get the actual deck height. You then cc just the combustion chamber and not the "squish" area outside of it. Tricky, eh?
Remember to mic the cylinder base gasket you have in there as well since you must set your final shim thickness without that there.
You can get cylinder shims in packs of four in thicknesses up to .060" IIRC. They must be carefully deburred then mic'd & I found them to vary quite a bit within a pack, so order two packs & return what you don't use.
Enjoy the build!

EMW has common sizes in stock, Rimco surface grinds shims to your specs.
Never stack to get that thickness and never stack more than 3 shims.

The only way to properly measure head CC is with a plate and CC measuring device such as a burette or at least a syringe.

I have a syringe ( no needle) ill have to figure out a plate tonight.

I made my plate from acrylic.
You want to be able to see through it while you fill.

The hypo needle was from a farm supply store (60cc)



Stu

piece of clear plexiglass with a hole in the middle so you can see any bubbles.

place the head on a foam block and make it level.

Plexiglass piece goes down inside the head sitting flush with the plane at which the cylinder would touch.

Use transmission fluid for measuring to make it easy to see and thick to prevent bubbles.

Rich

I put two small holes in mine. The extra one lets the air out. No bubbles.

hmm.. I dont have any plexiglass.. sounds like shopping to me...

Done... I managed to get 64cc on all four chambers.. I used water so you can't see it in the pic.
Oh.. and I don't seem to have that step in the chamber you speak of wndsrfr.

Ok on the CB performance calculator... I put in 64cc for heads along with my 96mm pistons and 80mm crank. Shooting for 9.5:1 compression. Looks like I want a deck height of .022". That in addition to my .052" that I am above the cylinders now ( with the base gasket at .006"). So. If I loose the base gasket then I want a .080" cylinder shim... sound about right ?

Based on reading a lot of threads about compression ratio, my understanding is that you dont want any deck less than .030.

Jake even once stated that under .025 and you are asking for problems (based on memory, and not recent research)

To get my CR up, I had the heads taken down a little.
My chambers are 54cc now.

I assembled my engine recently with less than .030 deck and got nervous and took it apart again to shim to .035.

Stu

That's a good point.. I seem to remember that also now.. I'll reduce my expectation down to 9.1. That would mean that I'd need a .041 deck height. Which with my proud pistons would mean I need a .093 spacer if I do not keep the base shim.

Can I do this thickness with the 3 smaller shims?

Do you have pistons that have valve relief pockets?

0.30 is to prevent the valve from hitting the piston.
With valve reliefs, you can adjust, but it's based upon your camshaft lift...so lots of measuring and you need to factor in valve float so you NEVER tap a valve with a piston.

With valve reliefs, you also need to factor in those pockets into your overall chamber size when you are calculating compression ratio.

64cc is a huge chamber....

The pistons are flat tops. So I guess that wouldn't apply. Ill keep the deck height more than .035 to be safe .... I'm not sure what to say about the chambers. I had a 60cc syringe and it took the hole thing plus about 4ccs of a second one to get rid of the air bubbles with me lightly pressing down on the plexi.

My understanding is that you need at least .025 clearance to keep the piston from hitting the flat part of the head that outlines the combustion chamber when hot.

This would obviously vary based on a number of variables, piston material is just one.

Stu

Sounds to me like you had a negative deck of .052 and that you'll need a .085 shim to reach a positive deck height thats "mechanically safe".

With a super tall deck of .146" the engine will be hard to tune and will need a lot of advance, despite the actual CR. Tall decks lead to inefficiency.

.085 min shim/spacer sounds about correct Jake. The .146 was what I came up with before I CC's my heads and put in 55 for a random number to start figuring it out. Once i CC's the heads at 64cc it all became much clearer. I believe I've located some shims. I'll place an order tomorrow. Then waiting......

64cc sounds big for those heads, my heads are 64cc and they are 103's with a step and unshrouded valves.

IIRC those have no step and are stock chambers (with big valves 44x38mm) you might want to CC your heads again to double check.

64cc is right for original 2L heads.
The cylinder diameter doesn't impact the head cc as it's not part of the head chamber.

Most original heads have 56-57cc, a rare occasion might find something at 58ccs, but I have never seen anything larger than that.

It does if you unshroud the valves and add a step.

I just went out and measured them again.. with my plexi plate sitting flat with 2 holes drilled in it ( one for fluid , one for air to escape) each chamber took a full 60cc syringe and then 4cc from a second syringe. I pulled the plexi plate off after I was done and there was no water around the chamber.

When I did mine the first time (pics above) I got almost exactly 60cc which I thought coincidental since my syringe was 60cc.

It might have a little to do with what spark plug you choose, but no more than 1cc or so variation.

Stu

I thought it would be closer to 60cc....if using water put a couple of drops of soap in it to break the surface tension.

Is the plexiglass plate sitting on the same plane tht the cylinder sits on or are you up higher so the plate is on top of the head...

Hard to describe, but please post a picture of the placement of the plexiglass.

Honestly, that is a big number.

In looking at the picture you did post, it does not appear to me that your plate is NOT sitting flat and some of the fluid seems to be sitting up on the edge of the cylinder hole.

That measurement is just of all the space below that level so it's quite possible you have 5 or more cc,s of fluid up around the edge.

Sorry to be anal about this, but it's a pretty critical measurement to get things correct.

I agree with Rich. The fluid is visible running under
and out the edge of the plexi. I use a
very thin flim of oil on the very edge and push down and twist a bit
to form a seal. There must be no fluid on the flat surface.

The picture I posted could not of had fluid running under the edge of the plexi because the picture that i posted was before I injected the water into that chamber.. you can see that the syringe is full... Perhaps you are refering to the picture that Stugray posted.
The plexi ( although a rough cut circle) covers the whole chamber and is sitting flat on the chamber face.

Here is the plexi sitting flat on the surface. Again its pretty rough cut as all I had to cut it with was a dremel tool.. but its flat on the chamber surface and there is no step.

And here it is with 64cc in it. If i try to put more in to get rid of that bubble, then it will come out the sides.

I've never seen a stock 2.0 chamber bigger than 61cc's.
Just sayin'.

Then I have no clue what I'm doing wrong here. I have measured all 4 chambers atleast half a dozen times and got the same readings +\- 1 cc. The plate is flat on the surface that the chamber is cut out of and I can put more than a full 60cc syringe in it

It looks to me like some metal has been removed around the exhaust valve, maybe that's added a smidge of volume..
Now that you have Len Hoffman's attention, all will be fine...just stick with it.
Can't resist asking if there's a Canadian conversion factor on the syringe....eh??

Lol. Good point but no. 1 cc is the same as 1 ml and the syringe is marked for 60 ml or just over 2 oz.
yes mark did do some work around the valves. I'm assuming for the larger valves.

My bad. I was indeed looking at stu's post.

picked up some ATF today and tried again... got slightly different numbers.. It is easier to see if the ATF is seeping out of the plexi and was easier to control air bubbles. Got 62-63cc's still though.. Any more and it would seep out the sides.

Occam's razor:

Either your chambers ARE greater than 60ccs regardless of what the experts say
OR
Your syringe is off (by ~7%)

Oh, and instead of cleaning up a mess of power steering fluid (eats paint BTW) I just put kool aid in my water ;-)

I crack up every time I see your plexi-cutting job ;-) Looks like you have a pet beaver :-)

Ace sells an adjustable circle cutter for ~$20
Just the recessed portion of those intake valves are probably 1-2 ccs

Stu

If all four are 62cc then so be it.
Use those to calculate your shims.

You need minimum of 030 deck height.
Use a CR calculator to see what that would give you for a CR and post that.
If it ends up being to low of a CR, you may want to fly cut those heads to reduce the chamber size.

Rich

You may also be able to replace the intake valve with a flat top version to reduce the chamber size.

The intake valve dish is ~.5cc's IIRC. I use the same valves here.
If your valves are leaking you'll get a higher #. Any fluid in the ports after a test?

Nope no fluid in the ports or around the spark plug.

Should be good.. I'll shoot for 9.2:1 compression, which should keep the cam happy and I'll have a deck height ( after shims ) of .047"....


Oh and Stugray ... 1: I hope the syringe isnt off by 7% .. its from a med kit... mind you, if the dr's were giving an extra 7% of meds it would explain why Canadians are usually in such a good mood.
2: No pet bevers in town... city bylaws frown upon that for some reason.. sure would help clear the trees after the big storms we just had.. ;-) The plexi thing was a "get to the store right before it closes so I can get in and out" kinda thing.... meh.. it works..

:-)

Hey MrHyde!

What length rods are you running?

I use a thin layer of vasoline on the edge of the plexiglass to keep the fluid from leaking out. I also have a nice, perfectly round piece of plexi that I use, though Thicker helps as deforming plexi causes numbers to be off. I have model engine fuel that is tinted that I use as it is free and easy and does not eat paint.

get a different syringe. show us what you are using. 64cc...hmm. or get a graduated cylinder and check your syringe

Just a quick tip, not sure if you did this or not. Mate your cylinder up with the head and make sure that the top edge of the cylinder bore comes into contact with the mating surface inside the head before the top cylinder fin hits that little 1/4" wide 1mm tall aluminum bump around the top edge of the combustion chamber.

I had to get that bump cut down on mine so that the mating surface would make contact. Delayed me a week but I'm just glad I found it, that would've made for a bad startup. Make sure to put head gaskets in when you check this (if you will use them)