Max deck and/or compression?- Now unshrouding-increase cc's

[mxracer]

With the questions answered/confirmed below it's on to working the heads to get more volume.

Looking for a little advice.

Here's what I have.

74mm Crank
90.5 P&C
Engle 110 Cam
Stock ported heads with 35x40 valves.

Issue is heads only have 41cc volume.

If I target a 9.5:1 compression ratio I'd need a .092 deck.

If I target even a .060 deck I'm at 10.1:1 compression and .050 is about 10.5.

I don't think the 110 will play nice with 10+:1, so that the first question...is that above the limit for the cam?

Second is...is .092 deck too much? I know it's at least on the outside of max deck but looking for others experience as well.

I guess another question would be if neither of those will work would I be able to get 5-6cc out of the chambers?

Thanks in advance for input.

[fastfil]

yes
and yes..

[mark tucker]

get a lot biger cam and or do a good bit of chamber work to open them pupys up.

[jfats808]

What about running a bigger cam ie: W120/125 with 1.1s? Not much to work with on the head ccs. What about dishing the pistons?
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2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125

[SRP1]

What carburetion and gearing are you running? A bigger cam may be helpful, or maybe not? Depends on a few factors.

I think the best solution is to look into having the pistons dished, and go for a deck of .070" but no more!......

[vwracerdave]

Once you flycut heads down to 41cc you can not make them bigger again. Your best choice would be to sell those heads and get another set that fits your needs.
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2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[Arnolds64]

I had a 110 with my 2017. 110's need to be more in the 8.5.1 range. That is where I was at and had to open the chambers up on my 043 40x35 heads. I opened them to 62 ccs to run a low deck of .040. So yes you can take out 5 to 6 ccs pretty easy. Go to www.cal-look.com and in the articles section go to the bottom and click on "older articles". Look for the DIY head Porting/ Chamber article. This is what I used for my own DIY. You want a tight deck for a complete burn and good squish. A large deck makes for also hot cylinders since your combustion is happening in the cylinders instead of most of it in the head chamber. With good rods you can go to .040. With a stroker you can get away with large cams. The crank will give a the bottom end to be a good in traffic performer. Couple that with a stock length rod with good bolts or with some 4340 Rods like I beams or whatever such as those from Aircooled.nets. I am running 5.5" (H Beams) longer rods which reduces the low end torque some with a 78.4 crank and with the 130Engle. The 130 has 308 duration and 267 @ .050. This is consider pretty stout with the duration but, it is very linear. Plenty of torque and tons of power above 4000 to almost 7000. With this engine I had to flycut the heads by .060 to get the chambers to 50cc to bring the C/R up to 10.1 range for the 130 which it likes.

With your smaller stroker engine I think a 120 would be a minimum cam. What carbs do you have and that is another factor. 120 is a about as large as you want to go with 40 IDFs. 44's for a 125 and above. The long .050 duration will cause a reversion issue with the 40's with a short power band and the low torque cammy low end.
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64 Bug, White, 2017, Dual Weber 44's, Engle 130/Engle lifters, Home P&P'd 40X35 heads, CB 4340 nitrided crank, Eagle knock off H Beam 5.5" rods, Lowering Beam, Rancho Trans, Traction Bar. 225X60's rear, 145's front on Porsche Chrome Nipple Wheels.

[kielbasa]

.092 is on high side, will it run? Yes, will it run terrible? No it will run just fine it just won't be up to its full potential. I've seen motors running twice as much deck... my own motor was .095 deck, but after some valve guide problems I decided to be froggy and go for the 11:1cr at .062 deck. Hoping the 7.4:1dcr will like 91octane still working on a few things.
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[modok]

It is possible to carve the heads out to 50cc, not easy or simple but "possible".

[Quokka42]

Go for a 40 thou deck and re-jet for E85
_________________
There has only ever been one man who was perfect, and they nailed Him to a cross.

[midtravelmidengine]

[mxracer]

Thanks so far guys.

Looks like some chamber work is on the horizon.

Here are a couple of pics of one of the heads.

This is the way the chambers came to me. Previous machine work to open them up to 90.5 and install bigger valves was already done by another shop.

I scribed the cylinder wall into the head, hope you can make that out.

[SRP1]

Oh yea! you can chisel those out some, just be careful not to remove to much of the quench pad and your good to go!

[mark tucker]

you have a ;lot to work with, they have already been welded up so you dont have a lot to loose if you eff them up.

[fastfil]

Start with some unshrouding. Thats a win, win deal. Get one chamber close, stencil it and do the others.

[Arnolds64]

[mxracer]

So I've been playing a little....
I took a junk head I had laying around, QUICKLY bored it out to 90.5 (so I know there are chatter marks etc. I didn't care about the boring), scribed the cylinders and started playing. These are also stock valves so the unshrouding looks HUGE.

Here's what I started with.....

This was the 2nd pass before I quit. I got 4cc from the first pass but haven't cc'd it again yet. I am guessing I'm at 51 now. I haven't touched the side opposite the plug yet, except to blend the cut around the valve. Also learned a lesson. I took the first cut on the mill with a boring head and got too deep. Thus the ledges right around the valves. IF I do it again it won't go as deep so I can blend it better. Let me have it.

[ralf]

based on ur last pic

trim down the area behind the plug ... and remove the S curve/eye brow above it

should give u a few cc's and emulate a "central" plug as far as the combustion cycle goes...

it would also mean u retain max quench area on the opposite side of the plug
_________________
Flow Through a Curved Conduit

porting my SP head for my brother's project
https://youtu.be/OS_mVjQuqgk

[ralf]

double post pft!
_________________
Flow Through a Curved Conduit

porting my SP head for my brother's project
https://youtu.be/OS_mVjQuqgk

[mxracer]

Second attempt at shape.....this more what I'm looking for in the end?

The first head I played with I ended up getting 5+ cc's out of so I think I'm good on getting enough volume.