Recommendations, boring, ballancing

[Mekanix]

Here is the current state of things





I've also made a manual tenssioner out of a spare.

[rapidray]

Here is the current state of things





I've also made a manual tenssioner out of a spare.

You need to rethink that tensioner. Call me & I will tell you what needs to be changed & you will understand why. Or, you can look at one of the APE tensioner pictures & you might be able to see what I am getting at. Ray.

[Mekanix]

Ok, I'll call asap.

It was easy to make so I just gave it a try.


Looking at the two the only things I see different are:

The overall length is too long but that was on purpose until It was installed in a mockup.

The end doesn't have a flat stub to push on the guide but the bolt is a 7/16, so it is still wide.

There is nothing to seal around the nut but I'm working on it.

Other than that, the center is a steel insert into an aluminum housing.

I did drill through it and install set screws so it wouldn't back out.

Besides that I don't know :P

[Mekanix]

Called Ray, No answer, I'll try again.

In the meantime I've mocked up the top end with washers that give me a 1mm (0.040) deck height with the head torqued.

I can get gaskets from cometic in the following sizes:

Base Gaskets

Fiber: Available Thicknesses: .012", .015", .020", .031", .039", .047", .060", .094", .125"
Spring Steel: Available Thicknesses: .010", .014”, .020"
Copper: Available Thicknesses: .005", .010", .016", .020", .027", .032", .043", .050", .063", .080", .094"

Head Gaskets:
Copper: Available Thicknesses: .005", .010", .016", .020", .027", .032", .043", .050", .063", .080", .094"
Steel Reinforced Fiber: Available Thicknesses: .043”, .059"

Thinking to go with 0.110" combination comprising of a 0.063" base and 0.050" head gasket.

Then again the combination of 0.094" base and 0.016" head also gives the same result but with more piston in the hole.

Whats better, more or less piston in or out of the hole ?

I could go 0.066", 0.022", 0.009", out of the hole with different base gaskets or up to 0.022 in the hole.



When I spoke with Ray, he said the valves probably wouldn't hit.

Surprisingly there is actually no valve contact!

Intakes are 0.030" so that is going to need some extra clearance.

The exhausts are well out of the way > than 0.040"

I'm working on the exact numbers and degrees at the moment.

[7981GS]

I would attempt to explain quench but there are experts here that know much better. (And would only try to insult me anyway)
Their engines don't always run though.
Has anyone ever heard/seen a running engine or bike from these experts?

Just sayin'

Eric

[Mekanix]

No idea, but I'll take all the information and advice I can get from everyone and do my own research before I decide the way I want to go.

I often learn something crucial just before I'm about to make a final decision. I often also make mistakes so I don't blame anyone for trying.



I'm just wondering if the quench should be partially in the cylinder or out of it.

[rapidray]

For power & effeciency, you want the piston AT or very close to ZERO deck height with your base gasket installed. If you are saying that with NO gaskets the pistons are .040 OUT of the hole, you will need a .040 base gasket. With the pistons at a true zero deck height you want to use a .043 head gasket. The reason for a .043 head gasket is that at high rpm when the piston reaches the top of the stroke, with expansion & all bearing play removed the piston can get VERY close to .040 out of the hole. This leaves you an extra .003 as a safety margin. Keep in mind that the scenario I just stated is on a drag race engine with a roller bearing crank that sees almost 13,000 rpm. If you set your engine up with these same #s you will have no issues with the pistons hitting the head. Sorry but I was at work tonight & unable to answer my phone. I will be home after 1 pm, Pacific time if you want to call me on Saturday. Lastly, to Eric above, I have bikes that run & will put my white bike & a GRAND up against anything you have that goes as fast as your mouth! Ray.

[gearhead13]

I just wanted to ask if the cams were degreed before the valve to piston clay test. If so, what were they degreed at? If they were set as per stock, the measurement means little as stock timing can be out quite a bit.
I would rather move timing one degree instead of making new valve reliefs. Unless you are running big duration cams with lots of overlap I really doubt that the valve/piston interference would be an issue, but checking it is a good idea.

[Mekanix]

I just wanted to ask if the cams were degreed before the valve to piston clay test. If so, what were they degreed at? If they were set as per stock, the measurement means little as stock timing can be out quite a bit.
I would rather move timing one degree instead of making new valve reliefs. Unless you are running big duration cams with lots of overlap I really doubt that the valve/piston interference would be an issue, but checking it is a good idea.

They are stock cams in the "stock" position. I measured before dissasembly, and got the numbers (103/107) so that when I got to this point it would be close.

On the exhaust cam I can go 1 tooth in either direction before the valve touches, So there is quite a bit of room. I might not have to adjust the relief that much.

On the intake its closer, I believe its 0.030".



No worries Ray,

With no base gasket the piston is out of the hole by 0.072" +- 0.002" measured. It would be less when fully torqued.

There isn't any gaskets from cometic that match 0.072 but I can make a combination of gaskets that will work, or maybe find some aluminum that's 0.071" and make a new gasket.

I'll give you a call.

[mawg]

If you want to se a pretty good discussion on quench, static/dynamic compression ratio,and cam timing, check out : www.jeepstrokers.com With that in mind, 0.0 deck hight and .043 gasket sound real good.

[Mekanix]

If you want to se a pretty good discussion on quench, static/dynamic compression ratio,and cam timing, check out : www.jeepstrokers.com With that in mind, 0.0 deck hight and .043 gasket sound real good.

What section is that in ?


I could use my own combination of gasket and shim that came out to be 0.072 by pure luck


Or use a 0.063 copper with the new 0.010 GS500 base gasket to get the same results.


Still on the fence on using mine which is made up of an aluminum shim with coper gasket spray and a stock base gasket.

Or to just get the copper one from cometic when I make the order for the head gasket.

[mawg]

Go to FAQ section, at top of page, article on stroking jeep's 4.0 l six, and at bottom of page, compression ratio faq's.But the whole site is pretty cool if you like playing with engines, I think you qualify there.Really enjoying this build, keep up the great work.

[Mekanix]

Cool. Some good information on there. Some I know, Some I've recently learned.

Something new though is dynamic compression ratio.

I nave to check the cam timing to see how much the piston moves up in the bore before the intake valve is fully closed and then do the math for the new dynamic comp ratio.

[GregT]

Don't waste your time working all that out...take Ray's advice on a cam profile and try to get the static compression down to a workable figure.

Where you've got the chance to pick an expert's brain, take it.
Saves a lot of time....

[mawg]

On the other hand it might be fun to do the calculations for the 78mm bore and 67mm bore,just to see how it came from the factory and how the bigger bore affects this.Ihave no idea,but it'll give you something to do while you wait for info on how much you can get out of your JE's. It's out there, you just gotta believe.Are they 80-83 1100 #128324's?And I agree on getting your static ratio right first,especially as you may not have a lot of choices in longer duration intake cams.Though I wouldn't mind being wrong about that.