V-Twin Forum banner

1 - 20 of 24 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter #1
im on my 10th month of my 15 month deployment to iraq and ive got all kinds of parts for my 03 nightrain sitting at the house just waiting for me, now ill get to the question. i bought a set of TW37 for my train several months ago, when i bought the cams i was planning to stay mostly stock with the motor but since then i decided to go with a 95" kit 10.25 to 1, an s&s super E, a forcewinder, v&h pro pipe, and ported and polished heads. now i dont know if im going to have enough cam for that much compression, the bike will mainly just be rode on the street but i love the power, mainly bottom end TQ but im sure the bike will see a drag strip or 2 in its day. any advice on the cams, will they be enough or should i go to the 44's?

thanks in advance for the help
 

·
Premium Member
Joined
·
641 Posts
First, welcome! And thanks for all you do for this country. I would look at the 55 cam, but I am sure some of the guru`s on here will chime in.
 

·
Registered
Joined
·
917 Posts
10.25 cr is too high for tw37g cam in most applications.

If you are going to have your heads ported then follow the advice of your head porter as to which cams work best with his heads.
 

·
Premium Member
Joined
·
2,565 Posts
10.25 to 1 is about the limit for the R&R stage 2 or 2-1/2 cnc ported heads with that cam. We have been using the RR525 which is a bump up from the 37, has better linear power and more low end torque. Andrews must have liked it too because they are comming out with a 54 that is almost identical. These two cams, the 525 and the 54 are good for a little more compression (10.8 to 1) then we jump to the RR615. All of these cams are Andrews manufacture, the 54 will be available by the time you get back in chain and gear, the RR cams are gear. Hope this helps.
 

·
Registered
Joined
·
25 Posts
Discussion Starter #6
thanks

hey thanks for the input, this is my first real big inch build and i didnt want to go wrong, also how important is it that i go with a gear drive cam. will i regret it if i dont? and king where can i buy the 525's? how pricey are they and how long do you think it will be for 54 to come out
 

·
Registered
Joined
·
13,064 Posts
Domed pistons work well with aftermarket heads that are designed with them in mind. Most people that run ported stock heads use flat tops.
 

·
Banned
Joined
·
4,508 Posts
Pistons

We use domed units/stock heads all the time, as when we blend the chambers, during the porting process, the cc's increase, and we need to maintain the correct compression for any given set-up. We will use 11:1 pistons in an engine, on occasion. That does not mean that the engine is going to have a mechanical of 11:1. The given cc's and the cam bleed will dicatate.
 

·
Registered
Joined
·
13,064 Posts
HDMD88 said:
And WHY IS THAT?
Because the combustion chambers are designed that way. Ported stock heads are just that ported. If you want to weld it up and re-design the combustion chambers, that is fine, but that is extensive mods ans aftermarket heads that are designed for domed pistons should be cheaper.
 

·
Registered
Joined
·
13,064 Posts
Branch designs his heads and combustion chambers along with the piston. Edelbrock does the same with his JE pistons. Some heads are modified to use 2 spark plugs in each combustion chamber to get a controled burn, partially due to the dome blocking the spark from firing on the other side.
The HTTC heads are designed to work with HTTC pistons. There is a correlation between the pistons and combustion chambers. Many of the porters will weld and reshape the ports and combustion chamber for their builds.
I am not saying that domed pistons shouldn't be used, but I am saying that the compustion chamber was designed with flattops in mind. This combustion chamber works very well with both, but some head designers have made subtle changes for thier domed pistons.
 

·
Banned
Joined
·
4,508 Posts
Heads/pistons

route66paul said:
Branch designs his heads and combustion chambers along with the piston. Edelbrock does the same with his JE pistons. Some heads are modified to use 2 spark plugs in each combustion chamber to get a controled burn, partially due to the dome blocking the spark from firing on the other side.
The HTTC heads are designed to work with HTTC pistons. There is a correlation between the pistons and combustion chambers. Many of the porters will weld and reshape the ports and combustion chamber for their builds.
I am not saying that domed pistons shouldn't be used, but I am saying that the compustion chamber was designed with flattops in mind. This combustion chamber works very well with both, but some head designers have made subtle changes for thier domed pistons.
I agree that the correct chamber/piston design is beneficial to the build.
We will weld the chamber and re-shape as needed to establish 20 or 30 degree precision angles to match the piston angle, if needed, and or, weld the chamber, to create a bathtub, if needed. Or start with a blank-top piston, set the dome angle and chamber angle for correct squish,along with the compression height, establish the valve pockets, and then send it to Swain to be coated. Is that what you mean? All in a days work.
Scott
 

·
Registered
Joined
·
13,064 Posts
Exactley.:thumbsup:
 
1 - 20 of 24 Posts
Top