Compression, Not your average Engine Options

[Mblizzard]

Ok so as many know, I an building my dream engine. With lots of Type 4 Store goodies including Nickies, 78 mm crank, and 102mm P/Cs, LE-200 heads and a decent cam, I am looking at where I want my compression to be.

With a normal engine and quality components it seems that 8.5 to 9.5 is about the limit before heat and detonation become issues.

Don't have any measurements yet but playing around with some calculations and assuming a low deck height because I have a slight dish and or valve pockets in the pistons I could easily get to over 11 to 1.

But I am think that might not be a long lasting engine. Looking at going for 10 to 10.5.

Thoughts? (IMG:style_emoticons/default/blowup.gif)

[Montreal914]

So, after spending all that money at the type 4 store, they wont give you any advice on your combo?

Or the other way around, I assume you initially discussed your combo with someone over there before placing your order... (IMG:style_emoticons/default/confused24.gif)

[Mblizzard]

So, after spending all that money at the type 4 store, they wont give you any advice on your combo?

Or the other way around, I assume you initially discussed your combo with someone over there before placing your order... (IMG:style_emoticons/default/confused24.gif)

I did not ask them. But I am fairly sure they would not make a recommendation. It comes down to how you want to use the tools they give you. If they said set it a 11:1 if you want the highest HP and you want a nice daily driver then they share some responsibility for you using their tool in the wrong application.

[Mark Henry]

So, after spending all that money at the type 4 store, they wont give you any advice on your combo?

Or the other way around, I assume you initially discussed your combo with someone over there before placing your order... (IMG:style_emoticons/default/confused24.gif)

I did not ask them. But I am fairly sure they would not make a recommendation. It comes down to how you want to use the tools they give you. If they said set it a 11:1 if you want the highest HP and you want a nice daily driver then they share some responsibility for you using their tool in the wrong application.

Everything is a compromise, to get a drivable DD you will have to leave some HP on the table.

I use the 163/86B web cam, my favorite for an engine this size. Lots of torque, bit lopey idle, but usable for street.

[Mblizzard]

So, after spending all that money at the type 4 store, they wont give you any advice on your combo?

Or the other way around, I assume you initially discussed your combo with someone over there before placing your order... (IMG:style_emoticons/default/confused24.gif)

I did not ask them. But I am fairly sure they would not make a recommendation. It comes down to how you want to use the tools they give you. If they said set it a 11:1 if you want the highest HP and you want a nice daily driver then they share some responsibility for you using their tool in the wrong application.

Everything is a compromise, to get a drivable DD you will have to leave some HP on the table.

I use the 163/86B web cam, my favorite for an engine this size. Lots of torque, bit lopey idle, but usable for street.

Pretty much going with the Type 4 version of the 86b. Slightly more duration on the intake at 284 and more on the exhaust at 300.

Based on a suggestion from Len I am having the ports ceramic coated which will help with the heat.

Type 4 confirmed the 8.5-9.5:1 range.

[Mark Henry]

So, after spending all that money at the type 4 store, they wont give you any advice on your combo?

Or the other way around, I assume you initially discussed your combo with someone over there before placing your order... (IMG:style_emoticons/default/confused24.gif)

I did not ask them. But I am fairly sure they would not make a recommendation. It comes down to how you want to use the tools they give you. If they said set it a 11:1 if you want the highest HP and you want a nice daily driver then they share some responsibility for you using their tool in the wrong application.

Everything is a compromise, to get a drivable DD you will have to leave some HP on the table.

I use the 163/86B web cam, my favorite for an engine this size. Lots of torque, bit lopey idle, but usable for street.

Pretty much going with the Type 4 version of the 86b. Slightly more duration on the intake at 284 and more on the exhaust at 300.

Based on a suggestion from Len I am having the ports ceramic coated which will help with the heat.

Type 4 confirmed the 8.5-9.5:1 range.

Should be nice.
Make it thump, I'd aim for no less than 9:1, set your timing for no more than 28* total, run premium and detonation won't be an issue.

You could run regular gas at 8.5, but why the fuch would you want to do that for? (IMG:style_emoticons/default/slap.gif)


Nickies you can run tighter ring gaps and a tight deck. With big bore head chambers and unshrouded valves you'll find you have to run a tight deck to get the CR you want.

Buy the LN ARP head studs, I also have the ARP case though bolts, but IMHO they're not needed.

[Mblizzard]

So, after spending all that money at the type 4 store, they wont give you any advice on your combo?

Or the other way around, I assume you initially discussed your combo with someone over there before placing your order... (IMG:style_emoticons/default/confused24.gif)

I did not ask them. But I am fairly sure they would not make a recommendation. It comes down to how you want to use the tools they give you. If they said set it a 11:1 if you want the highest HP and you want a nice daily driver then they share some responsibility for you using their tool in the wrong application.

Everything is a compromise, to get a drivable DD you will have to leave some HP on the table.

I use the 163/86B web cam, my favorite for an engine this size. Lots of torque, bit lopey idle, but usable for street.

Pretty much going with the Type 4 version of the 86b. Slightly more duration on the intake at 284 and more on the exhaust at 300.

Based on a suggestion from Len I am having the ports ceramic coated which will help with the heat.

Type 4 confirmed the 8.5-9.5:1 range.

Should be nice.
Make it thump, I'd aim for no less than 9:1, set your timing for no more than 28* total, run premium and detonation won't be an issue.

You could run regular gas at 8.5, but why the fuch would you want to do that for? (IMG:style_emoticons/default/slap.gif)


Nickies you can run tighter ring gaps and a tight deck. With big bore head chambers and unshrouded valves you'll find you have to run a tight deck to get the CR you want.

Buy the LN ARP head studs, I also have the ARP case though bolts, but IMHO they're not needed.

No regular for me!

Len is waiting till I get deck height measured before doing heads in case I need to tighten up the deck height.

All ready purchased the head studs. But I did pass on the through bolts.