Merlin Heads

minorv8 · Post by **minorv8** » Fri Sep 06, 2013 9:12 am

Definitely the right decision to port the heads and remove that filled in corner and fin.

I take it you changed something else too ? When I ported my heads the change was not that dramatic

mgbloke · Post by **mgbloke** » Fri Sep 06, 2013 11:19 am

Jukka, with the downdraught inlet manifold the in filled corner is effectively part of the outside radius as the air moves into the cylinder head runner. The injector is also pointing pretty much straight at it.
Last winter I port matched the heads to the downdraught manifolds but then put the Huffaker and carb back on. I did notice a slight power gain at high rpm and felt it was more eager to rev.
There is no way I could have left those corners there.
Cheers

JP. · Post by **JP.** » Sat Sep 07, 2013 4:02 pm

Well, did just do nothing to the heads as I was advised not to by Charles ( RIP ) from Real Steel.
Had a tour through the shop and where told every ins and outs of the heads by Charles.
Told Charles our engine combo and made him decide if suitable.

Just fitted them on my 3.5 back then without doing anything. ( so those "corners" are still there )
They made a huge improvement on the rollers & ET.
So to speak, figures stayed almost the same.. but instead of Engine horse power it now was wheel horsepower + some extra .

Running them for years now. 2007 batch, the first batch and bought the 31cc version of it. Ohh and they where cheaper back then.

Just made me wonder, where did the tale came from to modify those corners....
Real Steel must have develop them with a purpose..... Charles can't explain it any more.
I "Personally" cant believe they did create a not functional object.

Personally I don't bother about it, somebody always be quicker than me...
Guess the best next combo for me will be a twin turbo Viper engine as low budged big bang engine.

minorv8 · Post by **minorv8** » Sat Sep 14, 2013 2:41 pm

I don't think there's a specific tale. I justbdid not like the layout of the port. So I cut both the corner and the fin inside the port. If it was a sort of Band Aid or whatever to put them in there or not ? Don' t know put I cut them anyway. At least now they resemble an intake port and also seem to work

mgbloke · Post by **mgbloke** » Sat Sep 21, 2013 7:23 pm

You wouldn't believe the grief I am having with this clutch. I had to send it back to AP racing after I couldn't get it working. I even replaced master and slave cylinders. Anyway it should all be back together tomorrow and if all is OK am expecting to get it back on the rolling road Friday 27th to optimise the mapping and find out what power its making.
it also now spits flames on the over run see pic.

mgbv8 · Post by **mgbv8** » Sat Sep 21, 2013 8:07 pm

mgbloke wrote:You wouldn't believe the grief I am having with this clutch. I had to send it back to AP racing after I couldn't get it working. I even replaced master and slave cylinders. Anyway it should all be back together tomorrow and if all is OK am expecting to get it back on the rolling road Friday 27th to optimise the mapping and find out what power its making.
it also now spits flames on the over run see pic.

EPIC picture

mgbloke · Post by **mgbloke** » Mon Sep 23, 2013 7:02 pm

Finally clutch sorted. Rolling road booked for 3rd Oct. will post results.
Mark

mgbloke · Post by **mgbloke** » Thu Oct 03, 2013 4:31 pm

At the rolling road today first run 356.5bhp with a bit of tweaking best was 368.7bhp at 5689rpm and torque 368.5 lb ft at 4574rpm
I call that a result. will scan dyno sheet and post later.

Mark

mgbloke · Post by **mgbloke** » Thu Oct 03, 2013 4:40 pm

kiwicar · Post by **kiwicar** » Thu Oct 03, 2013 5:34 pm

That is a nice healthy power curve. . . 1100 revs between peak torque and peak power is very good for a rover with that sort of power level and a good 5-600 revs before the power curve rolls off. . . . is that on the 238 degrees at .05"mechanical flat tappet cam you had in it before?
Best regards
Mike

mgbloke · Post by **mgbloke** » Thu Oct 03, 2013 5:54 pm

Mike
yes the same Real Steel M238 which has suddenly become very civilised.

bigaldart · Post by **bigaldart** » Thu Oct 03, 2013 6:47 pm

So all in all 75 bhp increase from the ported Merlins over the original set up, wow, that is very impressive, I expect the grin to last a while. Got to be worth more than 100 bhp under the blower on ours. Starts to look like a really good deal at the price. Of course will be another 2-300 for push rods and new studs but still a good deal. Congratulations.

Alan

bigaldart · Post by **bigaldart** » Thu Oct 03, 2013 7:00 pm

So all in all 75 bhp increase from the ported Merlins over the original set up, wow, that is very impressive, I expect the grin to last a while. Got to be worth more than 100 bhp under the blower on ours. Starts to look like a really good deal at the price. Of course will be another 2-300 for push rods and new studs but still a good deal. Congratulations.

Alan

kiwicar · Post by **kiwicar** » Thu Oct 03, 2013 7:17 pm

Hi
It does now beg the question . . . will it take another 8 or 10 degrees of cam timing. . . just you have nearly a thousand revs with the power within 10 bhp of peak that is pretty flat for a race engine. Though I think it is such a wide, smooth power band it will be a giggle to drive out of corners past the opposition with your elbow hanging out the window

Best regards
Mike

JP. · Post by **JP.** » Fri Oct 04, 2013 1:51 pm

mgbloke wrote:Well the previous figures were 326bhp at flywheel, Dyno sheet is in here somewhere.
I don't think it will be much more but throttle response and drivability should be greatly improved.
.

Guess you where surprised with the outcome....
I never had any doubts....

Merlins Rule

Congratulations mate.