Recommendations, boring, ballancing

[Guest]

Alrighty then, Thanks GregT

0.0035 it is.

I've got 1 aluminum gasket made 0.04" or 1.2mm

2 paper gaskets 0.02 or 0.5mm

and one thick gasket made from Garlock which is 0.157" or 4mm

I think with the right combination I can get the piston below the deck where compression would be acceptable.

 

[Guest]

Got the cylinder block back today. Looks good.

Rings didn't need gaping.
Bore was accurate.


How much will the new weight of the pistons affect balance and vibration?

There is approximately 20 grams in the difference per piston.



I just found out that the shop that would have done the balancing doesn't have the "aptitude" to do the work.

They certainly have the equipment and the knowledge but lack the will to do work on anything smaller than a 4 cylinder.


I don't know any another shops that can do the work other than one in Ontario.


thanks

 

[GregT]

How much will the different piston weight affect it ? Until you run it you won't know....
personally i doubt if you'll notice much change - it's a 180 deg crank with a balance shaft and they're not silky smooth as standard.

Local to me there's a 450 running with GS500 pistons - no rebalance attempted and none needed - it's acceptably smooth.

 

[Guest]

Wow I have no idea how I've missed this thread until now!

Subscribed for sure... if I ever decide to be mad with my 450 I can see how I can get this to work :twistedevil:

 

[Guest]

Thanks pete,


Looks like The head gasket is MIA,

Going to order another one.



But before I do.

Here is what I asked for

81 gs 450 gasket with 79mm bore and stock thickness. (copper)



Does this sound like a good choice ?
I plan on adjusting the squish with base gaskets /shims.

What about an 80 mm bore gasket instead?
that would increase the combustion chamber and require less base shimming.


And one more question: would an aluminum head gasket be acceptable?
I have some 2024 T4 aluminum sheets left, 2.5mm thick.
I could cut it to precise fit and treat it.
still have to decide on a sealing compound though. (I've been keeping track of the current sealing compound threads)



Thanks

 

[gearhead13]

With the Canada post strike you might want to think about your shipping options.
I have two things ordered that I dont if I will ever get

 

[Graham]

Thanks pete,


Looks like The head gasket is MIA,

Going to order another one.



But before I do.

Here is what I asked for

81 gs 450 gasket with 79mm bore and stock thickness. (copper)



Does this sound like a good choice ?
I plan on adjusting the squish with base gaskets /shims.

What about an 80 mm bore gasket instead?
that would increase the combustion chamber and require less base shimming.


And one more question: would an aluminum head gasket be acceptable?
I have some 2024 T4 aluminum sheets left, 2.5mm thick.
I could cut it to precise fit and treat it.
still have to decide on a sealing compound though. (I've been keeping track of the current sealing compound threads)



Thanks

Soft aluminum head gaskets were common in the late 60s and early 70s. 2.5mm is a little thick for a head gasket and I don?t know how hard the 2024 is. Use copper coat as a head gasket sealant if needed. If you?re going to make your head gasket then use 18 or 16 gauge sheet soft aluminum or copper. If you use copper then bake it after you cut it to take any temper out.

 

[Guest]

With the Canada post strike you might want to think about your shipping options.
I have two things ordered that I dont if I will ever get

You know, I just herd about that this morning on the radio. I guess that explains it.


Thanks Graham,

I have a few choices for aluminum but that one was the only one that thick. The rest are about half that thickness and vary in strength.

This is what it is:
http://en.wikipedia.org/wiki/2024_aluminium_alloy

I'm going to track down some copper coat and start cutting. In the end I should have 2 or 3 base gaskets and shims and 2 head gaskets.

 

[Nessism]

I think you are wasting your time with the aluminum gaskets. Copper maybe, but not aluminum, I doubt is will compress enough to be oil tight. Of course, if you can live with a dribble here and there, then it might be fine.

 

[Guest]

Back in the day,a lot of 836 Hondas had aluminum head gaskets.

 

[GregT]

Most of the modern stuff uses shim Aluminium head gaskets now.
They are however embossed in critical areas so that they compress slightly when tightened down.
If you do cut out your own gasket, copper or Aluminium will work. I personally don't use thicker than 1.2mm which is about 18 gauge.

 

[Guest]

This is the first base gasket I made. Its 1.15mm thick and easy to shape.

Its not shim stock though, that would have been easy to work with and adjust the height as needed.


I'd really like to get a move on with this project and start building but Its hard when waiting for parts.
That's one reason why I'm making them instead. And besides I have the time to do it while I'm waiting.

I doubt is will compress enough to be oil tight. Of course

That's what I was originally afraid of, and hoping that a gasket sealing compound would be the solution.

 

[Graham]

You know, I just herd about that this morning on the radio. I guess that explains it.


Thanks Graham,

I have a few choices for aluminum but that one was the only one that thick. The rest are about half that thickness and vary in strength.

This is what it is:
http://en.wikipedia.org/wiki/2024_aluminium_alloy

I'm going to track down some copper coat and start cutting. In the end I should have 2 or 3 base gaskets and shims and 2 head gaskets.

You don?t want tempered aluminum for a head gasket like 2024. Soft aluminum that will bend and not break like conduit, soda cans and foil. You may wish to O-ring your oil passages with an aluminum or copper gasket. The head gasket must be softer the aluminum cylinder head.
Copper Coat comes in a spray can and can be obtained at most auto parts stores. I have use Copper Coat on used OEM head gaskets with no ill effects.

 

[Guest]

You don’t want tempered aluminum for a head gasket like 2024.

That's good because it became just another base shim.

I'm trying to find some shim stock aluminum and at the same time I'm tracking down some copper sheet.

How Should I coat the aluminum shim's? Should it just be sprayed on and let dry. Thick or thin? should I bake it after coating it?
I could make some paper gaskets as well if needed. If I used more than one shim, should I use a paper shim in between?


How could I o-ring the oil passages ? (looking it up right now)

 

[Graham]

That's good because it became just another base shim.

I'm trying to find some shim stock aluminum and at the same time I'm tracking down some copper sheet.

This is the original head gasket. Its not round but the new one will be.

How Should I coat the aluminum shim's? Should it just be sprayed on and let dry. Thick or thin? should I bake it after coating it?
I could make some paper gaskets as well if needed. If I used more than one shim, should I use a paper shim in between?


How could I o-ring the oil passages ? (looking it up right now)

Yea just spray the copper coat on and let it become tacky to the touch.

Use an O-ring with a slightly larger ID than the OD of your oil passage. Use an O-ring slightly thicker then the gasket that it is going in. Enlarge the hole in the gasket for the oil passage the fit the O-ring. Install gasket and O-ring. The O-ring must not block the oil passage.

 

[Guest]

Use an O-ring with a slightly larger ID than the OD of your oil passage. Use an O-ring slightly thicker then the gasket that it is going in. Enlarge the hole in the gasket for the oil passage the fit the O-ring. Install gasket and O-ring. The O-ring must not block the oil passage.

Sounds good. I just need 4 high temp O-rings. ID 13mm, OD >1.5mm(shim)
Shim oil passage diameter should be >16mm (13mm+ 2x1.5mm)

ID 13 OD 17

 

[GregT]

Normal Viton O rings will be OK

 

[Guest]

Thanks, I'll get some.


I've been trying to do the math to find out what I need to do to achieve a 12.5:1 compression ratio but its getting the best of me lately.

here's what I know

bore 78mm
stroke 56.6mm
base shim 0.5 up to 3mm
with no base shim or gasket the piston should be 0.8mm above deck
Combustion chamber per cylinder is 15cc's measured
Head gasket ~1.5mm

Intended compression ratio 12.5:1



Originally

bore 67mm
stroke 56.6mm
head gasket 1.5mm
base gasket 0.5mm
with base gasket the piston is 0.3mm below deck
compression ratio is 10.5:1

 

[GregT]

Do it the accurate old fashioned way...trial assembly and a burette.
Just put a wipe of grease around the edge of the piston at TDC then you can use water as your measuring fluid.
CR is then cylinder swept volume plus measured volume at TDC divided by measured volume at TDC.
Any adjustments needed are easy as the volume calculations are just pieces of a parallel cylinder.
I'd mock it up with the base gasket which gives you around .040inch piston to head clearance.
Been through this many times but it doesn't get easier or quicker....

 

[Guest]

Sounds good GregT that's what I'll do.


I've been wondering what to do in order to fit the cylinder block onto the base.

The sleeves are slightly too wide to drop into the case.


Should I leave the engine in the frame and file down the sleeves ?

That might be a problem if I want to bore larger later on.
It might have an effect on dissipating heat or affect the strength of the bore in those places.

How much room should there be between the sleeve and the case ?


I think taking the case apart and filing the case to match the sleeve is the best scenario.

I don't feel right filing anything on the base while its intact either. I don't think its worth being lazy on. ( and I've thought, I could just tape everything off and be careful and vacume as I go...)


I acknowledge that this is a one-of modification but the base is still stock and I will still have all the stock parts in the end.

Should I be concerned with keeping a stock unmodified base and simply keep modifying the block I have been modifying ?