Deck Height?

[Silvermachine81]

I think thats the term?

I havent touched my 1074 with 1134 kitted engine for a few years now and have forgot how far the pistons should be sitting down in the bores.

That was the cause of my trouble so I now want to get that sorted...

Can anyone help?

 

[rosco15]

Piston should be level with the top of your block.

 

[BadBillyB]

How thick is the head gasket ?? Piston to head clearance should be .035" to .040" depending on how heavy the pistons are........Measurement should be made right above the end of the wrist pin as the piston can rock slightly in the bore.....Billy

 

[Silvermachine81]

I thought it was supposed to be just a few thou down in the bores?

Its a Wiseco graphite head gasket.

I'm away from home now for the next week so I will have to have another measure up when I get home.

The pistons are sitting approx 40 thou down as I have a large copper base gasket on as a spacer.

Someone had planed the head too much AND the cylinder block as well!?!?

I ended up with valve to piston issues, That is why I had to do the copper base gasket thing.

I'm going to have one last crack at it with some shorter duration cams and if that doesnt work then its time to get the brand new head ready to take the 1mm oversize valves.

 

[rosco15]

You should set the piston to -0- deck height. I think the head gasket is around .045 thou.. If you run too thick of a base gasket to sink the pistons in the bore you will lose a bunch of HP. I was once told that .025" down the hole cost 17 HP. If your having trouble with the valves hitting the piston make sure you are degreeing the cams correctly. If that is correct you may have to have the pistons fly cut so the valves don't hit. More relief in the valve pocket. A local machine shop around you could do that. Check out web camshafts web page. They have a calculator you can use to make sure you are doing the math correctly. I've had the problem twice. Once I was doing the math wrong and the other time I had to fly cut the pistons.

http://www.webcamshafts.com/

Look under degreeing in your cams

 

[RacingJake]

Get the pistons level with the block like Ryan said. Use a thinner base gasket/ shim's to get there. Then set the cams up with at least 50 thous on the intake, 75 thou on the exhaust with piston to valve clearance and you should be good to go.

 

[Silvermachine81]

Thanks Guys.

I know all about the Clearances I need, That was the problem.

Too close, Got the Fly cut done and the pockets deepened (More than I measured was necessary) but the problem remained for some god forsaken reason.

I packed a big hissy fit and it hasnt been touched for approx 2 3/4 years.

Now im going to try it with 1150 cams instead of Webcam 348's so im hoping it will all come together.

Will find out next weekend........

I'm sick to death of hearing bikes go roaring past my home while knowing mine sounds WWWWWWWWWWWAAAAAAAAAAAAAAAYYYYYYYYYYYYYYY better.

I need to hear that Big Suzuki Roar into life once again ;-)

I think you all will understand where im coming from ;-)

 

[rosco15]

When you degree the cams in do the math. Then go in the house and use webcams calculator. Just to double check yourself. I switched my numbers once and was on the wrong end of the degree wheel. I was getting 110 when I did the math. I plugged it in on webcams and found I was really low like 80 something. Fixed my problem.

 

[RacingJake]

Yeap I know what you mean. I still forget sometimes to start counting back from 180 degrees. I do a few dry runs before I change the timing just to get me on the same page.

 

[Silvermachine81]

Just double check yourself. I switched my numbers once and was on the wrong end of the degree wheel. I was getting 110 when I did the math. I plugged it in on webcams and found I was really low like 80 something. Fixed my problem.

I've made that mistake before too.

I have the old Vance and Hines video of modifying a gs1100 motor and they dont mention checking the opening and closing points on your degree wheel vs the cam specs so I had it wrong.

I now check that off the cam specs and manually check all that myself.

This problem is purely caused by too much being planed of the head + some being taken off the Cylinder block too.

I was once told that .025" down the hole cost 17 HP.

That would explain my 108 horses on the dyno!!!!
And that was when it had RS Mikunis and the 348 cams in!

You can see why I took it home and instantly stripped it down.

That kind of output from a motor in this state of tune was just embarassing.
ARRGGH

 

[rosco15]

Good Luck with it. That motor should probably be in the 130's. I got 128 with an 1166 kit, stock head, stock cams, good pipe, and 36 flat slides.

 

[Silvermachine81]

Right, Finally had some time today........

Pistons were just over 30 thou down the bores.

When measuring that it had a custom made 40 thou copper base gasket fitted (No longer needed as 40 thou has been removed from the pistons).

So if I run a GSX1150efe metal base gasket (10 thou) I should have them level with the bores or 2 thou down.

New EFE cams are similar lift to the Webcam 348s and the ramp is similar on one side but way less steep on the other.
Hopefully running those in the current head will solve the Valve to piston issues.................Hopefully.

I really dont want to use that brand new head I have.......I just like taking it out of the plastic bag and looking at it, so clean and shiny......Hehehe!!!!

Will post some pics of it soon just to tease you all!!!!!!!!

 

[Silvermachine81]

Sitting around 2+ thou down with the efe gasket in place.

Hard to be ultra accurate with the rings off.

A wee bit of rock it the block too as its a used gasket just for the dummy run....

Pistons might sit flat or just out once its tightened up.

Should I play it safe and just go with the stock paper gasket??

 

[rosco15]

I blew a paper gasket out at the side of the block about 2 years ago. Been afraid of the stock paper gaskets since then. Switched to a newer gasket material cometic is making. It's aluminum coated with foam. 20 thou thick. It's worked great for me.

I'm about at the same place you are. Got my cases together. Time to see what I need for a base gasket to get the piston level with the top of the block. Maybe tomorrow I'll tinker with it. Good luck