Merlin Heads

minorv8 · Post by **minorv8** » Sat Mar 13, 2010 3:06 am

I got most of the geometry corrected with lash caps although I am running hydraulic lifters.

mgbloke · Post by **mgbloke** » Sat Mar 13, 2010 8:57 am

Hello Jukka
I know we have slightly different setups but with the lash caps installed I was not happy with the angle that the top of the pushrod was sitting in the cup, which meant that the pushrod was not pushing squareley in the cup. Hope that makes sense.

I have decided to leave the infilled corner on the inlet and just remove the small amount of casting flash from ports and runners.

Really looking forward to getting it running.

Mark

CastleMGBV8 · Post by **CastleMGBV8** » Sat Mar 13, 2010 10:19 am

Anyone asked RS why the inlet port has that filled in corner?

Kevin.

mgbloke · Post by **mgbloke** » Sun Mar 21, 2010 3:53 pm

I did ask some time ago why the inlet had the unusual shape and didnt get a difinitive answer. Something about increased torque and the fin on the port floor. Didnt really make sense to me.

Pushrods turned up last week and I must say the service from Smith Brothers was excellent.
On the down side I forgot to mention that I wanted solid ends (without oil hole).
As I have previously suffered with over oiling at the rockers I dont really want any more oil supplied to the top end. To overcome this i have modified my solid lifters to prevent oil entering the pushrod. So now the lifter cup will be supplied with oil from the rocker shaft.

Adjuster end of rockers make contact with the rocker covers by about 4mm so will get some 10mm spacers made this week then the engine can go back in.

Mark

minorv8 · Post by **minorv8** » Sun Mar 21, 2010 7:39 pm

Yes, I got the same general reply to the shape and the vane in the port. Turbulence is good but I don´t see how it helps if the flow is turbulent already in the port. It is beneficial in most cases in the chamber.

As for the port vane, they are usually in the top of the port close to the guide. I did find an interesting quote about the subject, see http://speedtalk.com/forum/viewtopic.php?t=4785 . I spoke with Charles at RS and if I understood correctly they have tested the port with and without the vane. It was better with the vane. FWIW, I took my home ported big valve head and a Merlin to be flow tested and Merlins were 20 % better on intake and 9 % better on exhaust flow. I did get the same result as previously quoted here and also got a flow test results from RS. They are all pretty much equal.

I have also fitted 10 mm thick spacers.

mgbloke · Post by **mgbloke** » Mon Mar 22, 2010 8:35 am

Also Rocker shaft end supports dont fit with the Yella Terra roller rockers.
some pics.

minorv8 · Post by **minorv8** » Mon Mar 22, 2010 8:38 am

Also Rocker shaft end supports dont fit with the Yella Terra roller rockers.

I guess I forgot to mention that

Check also that your pushrods clear the head. What is the size of your primaries ?

mgbloke · Post by **mgbloke** » Mon Mar 22, 2010 2:48 pm

Jukka
Pushrods just clear. Primaries are 1 3/4"
I think you did mention about the rockershaft end supports not fitting.

Rocker cover spacers ordered £55 each should be able to refit engine at the weekend.

bigaldart · Post by **bigaldart** » Tue Mar 23, 2010 8:01 pm

Just out of interest what did you use for head fasteners, sorry if you answered before but I havn't seen it anywhere. Cheers.

Alan

mgbloke · Post by **mgbloke** » Tue Mar 23, 2010 8:32 pm

Using Real Steel ARP bolts but will be looking for a stud kit.

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minorv8 · Post by **minorv8** » Tue Mar 30, 2010 5:12 am

I had to remove the roller rockers because they were making a lot of mechanical tapping noise. I first though that the rockers were hitting the covers despite the 10 mm spacers but found out that this was not the case. I don´t know what was causing it but I did not have enough time to start investigating. I put the old crap back and no more noise.

The hew shafts have smaller diameter than worn std shafts so maybe the excessive clearance is the culprit. The ratio is the same 1,6:1 so there should not be more lift tha might make the valves hit the pistons.

mgbloke · Post by **mgbloke** » Tue Mar 30, 2010 7:41 pm

Jukka
Where did you get your rocker shafts from? My rockers are a snug fit on the shafts.
Engine now in place just need to sort out the wiring.

minorv8 · Post by **minorv8** » Wed Mar 31, 2010 6:09 am

Mine came from Rimmer Bros. I contacted them and all they had in stock were the same size. I think they were 20,52 mm or something like that and the worn std shaft was 20,61 measured from the middle of the shaft (between the adjacent rockers).

Real Steel did not have any shafts in stock. Where did you get yours ? I definitely need better ones.

Jukka

mgbloke · Post by **mgbloke** » Fri Apr 30, 2010 7:36 am

Well the wiring has taken longer than I thought, still Lots of small jobs to finish on the car but hoping to get it started this weekend.

Jukka
My Rocker shafts were from Real Steel

Cheers
Mark

Robrover · Post by **Robrover** » Sun May 02, 2010 7:59 am

I made up four rocker shaft end support brackets to fit the Yella Terras roller rockers on my Buick 300 heads after a shaft broke at the overhang during some over zealous driving of the 4.6 SD1.

To get clearance for these rockers under Rover P6 rocker covers I use two Felpro rubber rocker cover gaskets glued together.