Merlin Heads

Kev · Post by **Kev** » Fri May 09, 2008 7:09 pm

anyone using these heads from Real Steel? I haven't been able to find much independent info/comment about them on the web and as I need a pair of heads doing these seem a real bargain compared to having heads ported.

cheers
Kev

kiwicar · Post by **kiwicar** » Fri May 09, 2008 7:52 pm

One of the guys on here had a set when they first came out but he sold them on without fitting them. Other than that I don't know of anyone using them. However from the pictures that were posted they seem a big improvment on ported rover heads. The chambers are a good fast burn design that should allow a bit more compression, let you use a slightly leaner mixture and less timing. The flow figures claimed are also good as cast and they will allow more lift from the cam. Price wise it seams money better spent than on porting a set of rover heads.
Mike

Kev · Post by **Kev** » Sat May 10, 2008 10:40 am

kiwicar wrote:Price wise it seams money better spent than on porting a set of rover heads.
Mike

My thoughts exactly.

I've just spoken to John at Real Steel who tells me that the heads are on back order and there's a waiting list. He says they can't make them fast enough they're flying out the door.
Kev

kiwicar · Post by **kiwicar** » Sat May 10, 2008 1:59 pm

With those chambers, and if the flow is as good as claimed then they should give more power than the best ported standard rover heads as cast, just wish I knew of a report from someone who had used them.
Mike

minorv8 · Post by **minorv8** » Sun May 11, 2008 6:36 am

There is a video on YouTube showing a Rover 4,6 engine fitted with Merlin heads. If I have understood correctly it it a RPI engine.

Some info here: http://www.pistonheads.com/GASSING/topi ... 0&t=437827

The video: http://www.youtube.com/watch?v=FYBPQP-H0fY

JP. · Post by **JP.** » Sun May 11, 2008 7:25 am

They are superb

kiwicar · Post by **kiwicar** » Sun May 11, 2008 7:43 pm

Ah ! It looks like JP has a set fitted!

I would ask him

Mike

Post by **katanaman** » Sun May 11, 2008 10:55 pm

yes a bit more info than they are superb would be pretty good

desertrover · Post by **desertrover** » Fri May 23, 2008 8:29 pm

Hello,
r they any good for offroading, or r they for hi revs only?
Nobody fitted them?

kiwicar · Post by **kiwicar** » Sat May 24, 2008 10:28 pm

If you leave them as cast (ie don't go and polish them) then they will flow well at lower valve lift. Really it is your cam duration and overlap that dictates the rev range your engine runs in.
The cam has to open the valve far enough to make use of the flow in the heads, this often means with a flat tappet cam and a ported head you end up having to use a longer duration cam to get the valves to open far enough for long enough to make use of the porting (generally ported heads gain high lift flow at the expence of lower lift flow, that is unless your name is Vizard).
If you can get a high lift, short duration, wide lobe seperation angle cam (and high ratio rockers) then these heads should work well, but you will need more lift to make use of the heads.
Mike

desertrover · Post by **desertrover** » Sun Jun 01, 2008 6:33 pm

kiwicar wrote:If you leave them as cast (ie don't go and polish them) then they will flow well at lower valve lift. Really it is your cam duration and overlap that dictates the rev range your engine runs in.
The cam has to open the valve far enough to make use of the flow in the heads, this often means with a flat tappet cam and a ported head you end up having to use a longer duration cam to get the valves to open far enough for long enough to make use of the porting (generally ported heads gain high lift flow at the expence of lower lift flow, that is unless your name is Vizard).
If you can get a high lift, short duration, wide lobe seperation angle cam (and high ratio rockers) then these heads should work well, but you will need more lift to make use of the heads.
Mike

So I want to use a piper 270/108° with 11.3mm of lift.
Now I´m using my old 3.5l heads ( minor ported ) that unfortunately have a "second " port exhaustsides to pump fresh air into the exhaust for emmision reasons.
These are plugged.
Now I´m working on a pair of 4.6 heads, a little more than minor porting is done, standard valve size, standard valve guides etc.
What power, espe. torque gaines could I expect from Merli heads over my 4.6 heads?
Any ideas? Is it woth the money?