Merlin Heads

Wotland · Post by **Wotland** » Sun May 02, 2010 10:14 am

Eales Rocker shaft pedestals are pretty cheap.

Steel version has the advantage to be machined you can use wider 0.900" roller rockers (excepted ones with roller needle bearing - 0.990"). Washers required with stock rockers (0.680").

mgbloke · Post by **mgbloke** » Mon May 03, 2010 6:21 pm

Rocker shafts breaking is a worry. Have regularly tone over 6k rpm.

Started engine today. Sounds great, no leaks or problems so far.
Now all I need to do is re fit the seats and doors, tailgate and the new bonnet bulge. Then I can drive the thing and maybe make a visit to the rolling road.

Mark

mgbv8 · Post by **mgbv8** » Mon May 03, 2010 8:36 pm

Looking good mate!
Another MGB V8 to scare the Ford boys off eh

mgbloke · Post by **mgbloke** » Sun May 30, 2010 4:29 pm

Update
Drove the car for the first time today and all seems well. As I havent driven it for six months its a job to tell if its faster or not as is was scary fast before.
Gonna try and book a rolling road session friday to set timing and see how much power there is.

CastleMGBV8 · Post by **CastleMGBV8** » Tue Jun 01, 2010 3:56 pm

Mark,

Look forward to hearing your dyno results.

Kevin.

mgbloke · Post by **mgbloke** » Tue Jun 01, 2010 5:18 pm

Rolling Road booked for 9.0am Friday. Using same one as before.
Its a DASTEK and was new in 07. My last visit was 22/02/08 when the maximum power at wheels was 242.3bhp@5306rpm, at flywheel 292.5 bhp@5841rpm and torque 294 lbft @ 4244rpm.
Engine spec is
4.6 with 4.0L pistons CR 10.8:1 RS 238 mechanical cam. Roller rockers
Huffaker inlet with Edelbrock 500. Merlin heads, Maniflow exhaust with 45mm primaries 53mm secondaries and 63mm system

The only changes are the new Merlin heads and the exhaust.
Hoping to get over 300bhp
Will scan the results and post. Might even take the video camera for when the rod exits through theside of the block Lol

Mark

Speed 8 · Post by **Speed 8** » Tue Jun 01, 2010 5:51 pm

Good luck Mark, looking forward to your results.

mgbloke · Post by **mgbloke** » Fri Jun 04, 2010 11:18 am

Thanks Speed 8 Rolling road sessions always make me nervous.

Anyway Results are VERY good, much better than I expected. I have dropped the dyno sheet in to a friend to scan them so will post later.

The first run Showed power @ 318bhp which I was very pleased with.
Then they optimised the timing which as it turned out was slightly too advanced.
Final run 326bhp and 322 lbft torque.

I was hoping for around 310bhp so I am very pleased in deed.

My power to weight ratio is now 336bhp per tonne. Cant wait to get it on track.

Of course The new exhaust must have helped the power figures but I am still glad I chose to go down the Merlin Head route.
The heads are totally standard with the exception of removing casting flash and small imperfections to the runners.

Thanks to everyone for their advice.

Cheers

Mark

mgbloke · Post by **mgbloke** » Fri Jun 04, 2010 11:29 am

Here it is.

mgbloke · Post by **mgbloke** » Fri Jun 04, 2010 11:37 am

Just found my Old dyno sheet from 2008 for comparison.

mgbloke · Post by **mgbloke** » Fri Jun 04, 2010 11:38 am

OOPS wrong one try this

kiwicar · Post by **kiwicar** » Fri Jun 04, 2010 1:07 pm

I would say a 35 BHP improvment on a rover for a pair of heads is somthing to be very pleased with, especially when it is achieved with a smoother torque curve You should be well chuffed with that.
Best regards
Mike

CastleMGBV8 · Post by **CastleMGBV8** » Fri Jun 04, 2010 4:03 pm

Mark,

Excellent result and only 10 BHP less than the Real Steel 5 litre engine, considering you are conceding 450cc your engine is producing more BHP per litre than theirs, well done.

Kevin.

Speed 8 · Post by **Speed 8** » Fri Jun 04, 2010 5:45 pm

Stunning result Mark. A well build engine indeed. Cant wait to finish mine.

mgbloke · Post by **mgbloke** » Fri Jun 04, 2010 5:47 pm

Looks like the extra 450cc has a greater effect to torque than bhp.
RS 5.0 has a very flat torque curve helped by the longer stroke.

My 4,6 is very happy to rev way past 6krpm so now need to think about rocker shaft end supports as mentioned.

Very happy with the results.

Mark