HarleyTechTalk

Hey folks,

I'm looking for a little more on my next Evo softail 80" build. Looking at the Tman 625 cams (41 intake close) they call for around 10 - 10.5 compression and .650 lift valve springs.

If I go with this cam, and I use 10.5 comp .020" over pistons and a .030" head gasket, the calculator puts me at 10.85 compression... I can easily get 10-1 with 10.1 pistons but I really want the most out of the cam if I'm going this far.

Would it be a bad move to use a .045 head gasket? Or should I still be aiming for .030" - .035 Squish with the >030" head gaskets?

Thanks in advance.

Quote from: Adam76 on June 06, 2023, 06:38:41 PMHey folks,

I'm looking for a little more on my next Evo softail 80" build. Looking at the Tman 625 cams (41 intake close) they call for around 10 - 10.5 compression and .650 lift valve springs.

If I go with this cam, and I use 10.5 comp .020" over pistons and a .030" head gasket, the calculator puts me at 10.85 compression... I can easily get 10-1 with 10.1 pistons but I really want the most out of the cam if I'm going this far.

Would it be a bad move to use a .045 head gasket? Or should I still be aiming for .030" - .035 Squish with the >030" head gaskets?

Thanks in advance.

The .030 quench is what helps control the combustion as you get higher in compression.  I'd be inclined to keep it that way.  I may call TMan and ask him if he sees any problem running a tic more squeeze than he recommends.  I expect his response will depend upon what tuner device you use and if the dyno operator is capable of tuning a high compression engine.  You may have a little extra heat in the summer hot weather depending on where you are.

Thanks kd,

One thing you need to have and may already know, is manual compression releases if you start taking the compression up there.

Thanks Ohio, yes I have comp releases 

The other option is running the Woods W6H at 11 compression.

Another option is the Tman 590 and get it down to 10.56-1 comp with pistons down the hole .005" and .030" HG and 84cc heads (assuming they haven't been cut down already).

What do you guys think of these cam set ups?

Tman 590 at 10.56-1 comp (CCP 200) heads at 84cc
Woods W6H at 10.14 -1 comp (ccp 195) heads at 82cc
Tman 625 at 10.1 comp (ccp 194) with heads milled to 82cc
Vthunder 3030  10.56 comp 84cc heads (200ccp)


Thanks

Quote from: Adam76 on June 07, 2023, 08:03:39 PMAnother option is the Tman 590 and get it down to 10.56-1 comp with pistons down the hole .005" and .030" HG and 84cc heads (assuming they haven't been cut down already).

What do you guys think of these cam set ups?

Tman 590 at 10.56-1 comp (CCP 200) heads at 84cc
Woods W6H at 10.14 -1 comp (ccp 195) heads at 82cc
Tman 625 at 10.1 comp (ccp 194) with heads milled to 82cc
Vthunder 3030  10.56 comp 84cc heads (200ccp)


Thanks

My favorite Evo cam was/is a Powerhouse VIPER. always made in the 90 hp. range in 80" Evo engines, with my heads. Still use them today.
John

Thanks John, what compression do you set out up at?
Looks like it has a IVC of 50*
I'm looking for usable power from 2000 - 5000

Thanks

Quote from: kd on June 06, 2023, 06:48:49 PM

Quote from: Adam76 on June 06, 2023, 06:38:41 PMHey folks,

I'm looking for a little more on my next Evo softail 80" build. Looking at the Tman 625 cams (41 intake close) they call for around 10 - 10.5 compression and .650 lift valve springs.

If I go with this cam, and I use 10.5 comp .020" over pistons and a .030" head gasket, the calculator puts me at 10.85 compression... I can easily get 10-1 with 10.1 pistons but I really want the most out of the cam if I'm going this far.

Would it be a bad move to use a .045 head gasket? Or should I still be aiming for .030" - .035 Squish with the >030" head gaskets?

Thanks in advance.

The .030 quench is what helps control the combustion as you get higher in compression.  I'd be inclined to keep it that way.  I may call TMan and ask him if he sees any problem running a tic more squeeze than he recommends.  I expect his response will depend upon what tuner device you use and if the dyno operator is capable of tuning a high compression engine.  You may have a little extra heat in the summer hot weather depending on where you are.

Hey kd,
But a message from Tman about the 625 cam, and he said the optimum / Max compression for the cam is 10.5...

Scott St Hillside also said the MAX compression for the W6H is no more that 10.5.

The problem I'm having is -- how do I get to 10.5 compression???

The 10-1 pistons don't give me enough compression -- and the 10.5 pistons give me too much compression!!!

Is there a 10.25-1 evo piston? That would be helpful.

Thanks for your advice

Quote from: Adam76 on June 08, 2023, 03:46:50 PM

Quote from: kd on June 06, 2023, 06:48:49 PM

Quote from: Adam76 on June 06, 2023, 06:38:41 PMHey folks,

I'm looking for a little more on my next Evo softail 80" build. Looking at the Tman 625 cams (41 intake close) they call for around 10 - 10.5 compression and .650 lift valve springs.

If I go with this cam, and I use 10.5 comp .020" over pistons and a .030" head gasket, the calculator puts me at 10.85 compression... I can easily get 10-1 with 10.1 pistons but I really want the most out of the cam if I'm going this far.

Would it be a bad move to use a .045 head gasket? Or should I still be aiming for .030" - .035 Squish with the >030" head gaskets?

Thanks in advance.

The .030 quench is what helps control the combustion as you get higher in compression.  I'd be inclined to keep it that way.  I may call TMan and ask him if he sees any problem running a tic more squeeze than he recommends.  I expect his response will depend upon what tuner device you use and if the dyno operator is capable of tuning a high compression engine.  You may have a little extra heat in the summer hot weather depending on where you are.

Hey kd,
But a message from Tman about the 625 cam, and he said the optimum / Max compression for the cam is 10.5...

Scott St Hillside also said the MAX compression for the W6H is no more that 10.5.

The problem I'm having is -- how do I get to 10.5 compression???

The 10-1 pistons don't give me enough compression -- and the 10.5 pistons give me too much compression!!!

Is there a 10.25-1 evo piston? That would be helpful.

Thanks for your advice

It sounds like you don't have the pistons yet.  I don't know if anyone sells off the shelf 10.25:1 evo pistons (especially in +.020).  You could however go with the 10.5 and have them machined to make them work.  Also, if your upsizing valves and opening up the valve pockets those added CC's removed also will count.  I suppose this also depends on who you have available to do the work.

Quote from: kd on June 08, 2023, 08:57:12 PM

Quote from: Adam76 on June 08, 2023, 03:46:50 PM

Quote from: kd on June 06, 2023, 06:48:49 PM

Quote from: Adam76 on June 06, 2023, 06:38:41 PMHey folks,

I'm looking for a little more on my next Evo softail 80" build. Looking at the Tman 625 cams (41 intake close) they call for around 10 - 10.5 compression and .650 lift valve springs.

If I go with this cam, and I use 10.5 comp .020" over pistons and a .030" head gasket, the calculator puts me at 10.85 compression... I can easily get 10-1 with 10.1 pistons but I really want the most out of the cam if I'm going this far.

Would it be a bad move to use a .045 head gasket? Or should I still be aiming for .030" - .035 Squish with the >030" head gaskets?

Thanks in advance.

The .030 quench is what helps control the combustion as you get higher in compression.  I'd be inclined to keep it that way.  I may call TMan and ask him if he sees any problem running a tic more squeeze than he recommends.  I expect his response will depend upon what tuner device you use and if the dyno operator is capable of tuning a high compression engine.  You may have a little extra heat in the summer hot weather depending on where you are.

Hey kd,
But a message from Tman about the 625 cam, and he said the optimum / Max compression for the cam is 10.5...

Scott St Hillside also said the MAX compression for the W6H is no more that 10.5.

The problem I'm having is -- how do I get to 10.5 compression???

The 10-1 pistons don't give me enough compression -- and the 10.5 pistons give me too much compression!!!

Is there a 10.25-1 evo piston? That would be helpful.

Thanks for your advice

It sounds like you don't have the pistons yet.  I don't know if anyone sells off the shelf 10.25:1 evo pistons (especially in +.020).  You could however go with the 10.5 and have them machined to make them work.  Also, if your upsizing valves and opening up the valve pockets those added CC's removed also will count.  I suppose this also depends on who you have available to do the work.

Thanks kd,I really want to keep the build as simple as possible.

Pistons
Cam
Valve springs

Quote from: Adam76 on June 08, 2023, 03:42:52 PMThanks John, what compression do you set out up at?
Looks like it has a IVC of 50*
I'm looking for usable power from 2000 - 5000

Thanks

The Wood W6HF is closer in spec to the the T-Man 625. Very different cam than the W6H you refer to in this thread.

Someone mentioned something about which tuner was used. Is this an Evo with a carb?

Quote from: Adam76 on June 08, 2023, 09:15:50 PM

Quote from: kd on June 08, 2023, 08:57:12 PM

Quote from: Adam76 on June 08, 2023, 03:46:50 PM

Quote from: kd on June 06, 2023, 06:48:49 PM

Quote from: Adam76 on June 06, 2023, 06:38:41 PMHey folks,

I'm looking for a little more on my next Evo softail 80" build. Looking at the Tman 625 cams (41 intake close) they call for around 10 - 10.5 compression and .650 lift valve springs.

If I go with this cam, and I use 10.5 comp .020" over pistons and a .030" head gasket, the calculator puts me at 10.85 compression... I can easily get 10-1 with 10.1 pistons but I really want the most out of the cam if I'm going this far.

Would it be a bad move to use a .045 head gasket? Or should I still be aiming for .030" - .035 Squish with the >030" head gaskets?

Thanks in advance.

The .030 quench is what helps control the combustion as you get higher in compression.  I'd be inclined to keep it that way.  I may call TMan and ask him if he sees any problem running a tic more squeeze than he recommends.  I expect his response will depend upon what tuner device you use and if the dyno operator is capable of tuning a high compression engine.  You may have a little extra heat in the summer hot weather depending on where you are.

Hey kd,
But a message from Tman about the 625 cam, and he said the optimum / Max compression for the cam is 10.5...

Scott St Hillside also said the MAX compression for the W6H is no more that 10.5.

The problem I'm having is -- how do I get to 10.5 compression???

The 10-1 pistons don't give me enough compression -- and the 10.5 pistons give me too much compression!!!

Is there a 10.25-1 evo piston? That would be helpful.

Thanks for your advice

It sounds like you don't have the pistons yet.  I don't know if anyone sells off the shelf 10.25:1 evo pistons (especially in +.020).  You could however go with the 10.5 and have them machined to make them work.  Also, if your upsizing valves and opening up the valve pockets those added CC's removed also will count.  I suppose this also depends on who you have available to do the work.

Thanks kd,I really want to keep the build as simple as possible.

Pistons
Cam
Valve springs

You also have the option of cylinder base gasket dimension change.  Thicker will lower your compression and increase the quench (squish).  If you have been following Ohio's Stormbreaker build on Twin Cam you will see he is doing just that.  Try adding an increment of .010 to your head gasket dimension in the calculator you are using and it will simulate an increase in base gasket thickness.  If you are close now, it may be all you need to get there.

QuoteThe Wood W6HF is closer in spec to the the T-Man 625. Very different cam than the W6H you refer to in this thread.

Someone mentioned something about which tuner was used. Is this an Evo with a carb?

Thanks turboprop,
I haven't seen the W6F cam on the Woods website. The only one I see is the W7, which could work. But I don't want it to be a dog under 3000rpm.

And yes, it is carby. So tuning is a little less precise I guess.

Do you have experience with the W7 cam? This might be a good option with 10.7 compression.

Quote from: jsachs1My favorite Evo cam was/is a Powerhouse VIPER. always made in the 90 hp. range in 80" Evo engines, with my heads. Still use them today.
John

Hey John, looking into the Viper cams, which one exactly are you referring to? The 560V ?

Looks like a good candidate for 10.7 compression.

What are they like below 3000rpm in an 80" ?

Thanks

Adam,
560V. I use it with Wiseco 10.00:1, 12.9 cc dome pistons. The rest is in the heads.
John

Thanks John.
Sounds like a good combo. But with 10-1 compression pistons, I only get 10-1 compression and a low dynamic compression...
I thought the cam with an IVC of 50* would need at least 10.5  -  10.8 compression with the 10.5 comp pistons?

Trust your advice, just confused.
Also do I need .600  or  .650 lift valve springs?
Cheers

Power House
Grind Viper 560V.
By: ANDREWS PRODUCTS INC

"The best cam for higher compression 80 Cl 9:1/11:1 compression".

Stock or ported heads.  Very strong mid range with the ability to pull very hard up to about 6500 RPM depending on cylinder head air flow.

Quote from: Adam76 on June 11, 2023, 04:40:04 PMThanks John.
Sounds like a good combo. But with 10-1 compression pistons, I only get 10-1 compression and a low dynamic compression...
I thought the cam with an IVC of 50* would need at least 10.5  -  10.8 compression with the 10.5 comp pistons?

Trust your advice, just confused.
Also do I need .600  or  .650 lift valve springs?
Cheers

.600" lift springs is what you need to use. More compression? Mill the heads.
John

Quote from: jsachs1 on June 12, 2023, 03:08:12 PM

Quote from: Adam76 on June 11, 2023, 04:40:04 PMThanks John.
Sounds like a good combo. But with 10-1 compression pistons, I only get 10-1 compression and a low dynamic compression...
I thought the cam with an IVC of 50* would need at least 10.5  -  10.8 compression with the 10.5 comp pistons?

Trust your advice, just confused.
Also do I need .600  or  .650 lift valve springs?
Cheers

.600" lift springs is what you need to use. More compression? Mill the heads.
John

Thanks John.  I was going to set the heads at 83cc....

How low can I safely go with the heads?
 82cc / 81cc / 80cc ?

Thanks

Adam why not bath tub the heads 

Quote from: JSD on June 12, 2023, 10:19:46 PMAdam why not bath tub the heads

That's not a bad idea. Not sure what it would cost? $1500 all up? pretty expensive I'd guess...
If I don't do that, I  could use 10-1 Wiseco pistons and bring the compression up by milling the heads.

BTW how low can you go with cc's of the heads before you start to run into possible piston to valve clearance?

Would 80cc be ok?

Adam,
Mill your stock heads. You can go in the 70's range, with NO interference, and those pistons.
John

    You may have to file your manifold slightly to get some clearance if you cut the heads at the upper limits.  That will become obvious when you start to assemble it.