What problems would I run into when trying to put a set of GN1 stage II (4.1) on a 109? Is the combustion chamber a larger dia? Head gasket sealing issues? Valves are too close to cylinder walls?? Should I bore the 109 block, or modify the top of cylinder walls? Should I get the right heads??
4.1 heads on a 109?
- Thread starter turbo2nr
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Assuming you're talking about a Champion 14-bolt GN1 head, I'm pretty sure they will bolt on to the production 109 block and they use a production style cam. From what I know the TA Street Eliminator heads with the huge valves are the only heads that require a 4.1 bore. Bhen being on a 4.1 Stage II motor mainly means they are 14-bolt instead of the stock 8 bolt and the have huge port that might kill power at low rpm due to low port velocities. What are your goals with this motor?turbo2nr said:
109 is a 3.79" bore
4.1 engine is 3.96" bore
What would the perfect way be to put 4.1 heads on a 3.79" bore?
Just say F-it!?? Is that the deal then?
Aren't there two different head gaskets for 3.8 vs/ 4.1?
Which should I use? The 4.1? Otherwise, the top of gasket would be exposed in the larger chamber, right? Gets burned up. Right?
We have a little cylinder wall above TDC to play with. Taper or bevel it just a little and use a 4.1 gasket??
Champion's web site kind of stinks. Mentions nothing about different heads, shaft mount vs. pedestal, stage I, stage II nothing about GN1R. Just a little generic story about the heads in general.
So, are the combustion chambers identical on all the GN1 heads?? Who knows??
Why does the outside of my box say 4.1 liter. It already states the heads are 14bolt and Stage II, then it states it is for 4.1. So what the heck does that mean? Nothing?
4.1 engine is 3.96" bore
What would the perfect way be to put 4.1 heads on a 3.79" bore?
Just say F-it!?? Is that the deal then?
Aren't there two different head gaskets for 3.8 vs/ 4.1?
Which should I use? The 4.1? Otherwise, the top of gasket would be exposed in the larger chamber, right? Gets burned up. Right?
We have a little cylinder wall above TDC to play with. Taper or bevel it just a little and use a 4.1 gasket??
Champion's web site kind of stinks. Mentions nothing about different heads, shaft mount vs. pedestal, stage I, stage II nothing about GN1R. Just a little generic story about the heads in general.
So, are the combustion chambers identical on all the GN1 heads?? Who knows??
Why does the outside of my box say 4.1 liter. It already states the heads are 14bolt and Stage II, then it states it is for 4.1. So what the heck does that mean? Nothing?
Not having messed with GN1's or GN1R's I can't say about the valve sizes and bore interence. Do this, measure the valve sizes, throw a 3.8 headgasket on and measure the clearance between the valves the gasket bore and report the numbers. I have CNC Irons for my 4.1 and I'll measure the clearances with the 4.1 gaskets and the 3.8 gaskets. Either way I'd run the gasket that matchs the block and get the right heads if these don't work for you. Relieving the block I don't think is a good idea since you end up with a larger crevise volume and things don't burn well there and while you aren't concerned with emmisions, the nasty stuff generally results from innefficent combustion which is bad for any motor.
