“Merlin F85” heads for the Rover V8 from Real Steel

“Merlin F85” heads for the Rover V8 from Real Steel

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Discussion

jwoffshore

405 posts

214 months

Thursday 8th March 2012
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I found this article dating back to 2008, but it all seems remarkably quiet on this subject generally.
http://www.v8wizard.com/uploaded_files/2008Novembe...

When you figure the costs of modifying to get still very mediocre performace from the original Rover castings, plus all the trouble folks go to with fancy injection & induction set ups, I'm surprised nobody on here seems to have taken the plunge on these heads.

rev-erend

20,653 posts

244 months

Thursday 8th March 2012
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No point me doing it .. I have Wildcat heads on mine.

packman10_4

243 posts

154 months

Thursday 8th March 2012
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I think for the price of it a nice LS3 would do the job better , also way more tuning options , the rover is old hat now and development has gone as far as it can go.

Transmitter Man

4,200 posts

184 months

Thursday 8th March 2012
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Not strictly true;

From 1:20: http://www.youtube.com/watch?v=6fpiCdtrOL8&fea...

Phil

DonkeyApple

39,009 posts

129 months

Friday 9th March 2012
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I ended up looking into these heads. All the people who raved about them hadn't used them.

I was unable to find someone who had used them, was independent and able to verify that they made a significant difference.

If you're building an engine from scratch then it strikes me that building a Rover to the level that comfortable exceeds 300 but remains robust is going to cost more than a crate LS3.

Boosted LS1

19,469 posts

220 months

Friday 9th March 2012
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A single diy low boost turbo conversion on a stock rover would easily make well over 300 hp. The later rovers have much stronger pistons then the LS engines so they could support over 400 hp. You could probably source all the parts for under £1'500 and you'd get to keep the original gearbox. The rover's still got a lot going for it imo.

DonkeyApple

39,009 posts

129 months

Friday 9th March 2012
quotequote all
Boosted LS1 said:
A single diy low boost turbo conversion on a stock rover would easily make well over 300 hp. The later rovers have much stronger pistons then the LS engines so they could support over 400 hp. You could probably source all the parts for under £1'500 and you'd get to keep the original gearbox. The rover's still got a lot going for it imo.
But it is strange that an engine that is so ubiquitous that there are so few options for it in terms of modern designed top ends etc.

Transmitter Man

4,200 posts

184 months

Saturday 10th March 2012
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Donkey,

There's actually a reasonable amount of after market hardware out there if you look hard enough, carbs/intakes, ITB intakes, roller rockers, around four different head suppliers including the Merlins.

What else are you after?

Phil

spend

12,581 posts

211 months

Sunday 11th March 2012
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DonkeyApple said:
If you're building an engine from scratch then it strikes me that building a Rover to the level that comfortable exceeds 300 but remains robust is going to cost more than a crate LS3.
A 4.6 RV8 with higher comp pistons ( from the 4.0), larger valves (fitting standard seats recut) & decent cam should easily achieve that without costing a deal more than a std rebuild. There are plenty of examples, maybe with a few more tweaks to the induction and ECU, which easily achieve those numbers (+@10%) & reliability.



DonkeyApple

39,009 posts

129 months

Sunday 11th March 2012
quotequote all
spend said:
A 4.6 RV8 with higher comp pistons ( from the 4.0), larger valves (fitting standard seats recut) & decent cam should easily achieve that without costing a deal more than a std rebuild. There are plenty of examples, maybe with a few more tweaks to the induction and ECU, which easily achieve those numbers (+@10%) & reliability.
Indeed. Building a 300 bhp engine that is strong and reliable is pretty textbook but I'm talking about the diminishing returns of pushing beyond that. A Chevy lump put of a crate is probably already cheaper than building a RV8 with the same ancillaries etc. beyond that it tough to way up the difference of spending money pushing for more on the Rover or making the changes to run te Chevy.

eff eff

698 posts

164 months

Sunday 11th March 2012
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When I did the sums the Chevy won hands down on cost per BHP, not to mention reliability, fuel economy and performance parts availability

Boosted LS1

19,469 posts

220 months

Sunday 11th March 2012
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The chevy as a crate engine is very attractively priced. It's the rest of the stuff you need that makes it expensive. For big power it has to be the chevy but for 300bhp n/a or 400 turbo then the rover would be a cheaper engine to modify. In fact, the engine could probably be left unchanged internally.

robrover

41 posts

176 months

Wednesday 4th April 2012
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My Buick 300 heads have been flowed to develop a potential 410hp. On a 5.5 Rover that can make good power. If I went LS I'd have to change the gearbox, diff, axles, bigger brakes, induction, the list goes on. 400 bhp is about right in a road car. If you want to really fly go buy the latest Nissan GTR twin turbo V6 for AUD$175,000 - 0 to 60mph in 2.8 seconds.

dbv8

8,515 posts

180 months

Wednesday 4th April 2012
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robrover said:
If you want to really fly go buy the latest Nissan GTR twin turbo V6 for AUD$175,000
or just add gas. Its a bit cheaper.

My engine.... 4.6 with 4.0 pistons, real steel typhoon cam, 500 heads, decat, blended trumpet base, 72mm plenum and megasquirt. Gave 275 @ wheels on 95 ron petrol (V-power sold out due to panic buying).
Add some nitrous.... 418bhp and 440lb/ft for 0-100 in 7.5.

Transmitter Man

4,200 posts

184 months

Wednesday 4th April 2012
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Rob,

Any actual flow data to hand?

Phil

rev-erend

20,653 posts

244 months

Thursday 5th April 2012
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dbv8 said:
or just add gas. Its a bit cheaper.

My engine.... 4.6 with 4.0 pistons, real steel typhoon cam, 500 heads, decat, blended trumpet base, 72mm plenum and megasquirt. Gave 275 @ wheels on 95 ron petrol (V-power sold out due to panic buying).
Add some nitrous.... 418bhp and 440lb/ft for 0-100 in 7.5.
Love the use of past tense.. 'gave'

How is the rebuild going ?

dbv8

8,515 posts

180 months

Thursday 5th April 2012
quotequote all
rev-erend said:
dbv8 said:
or just add gas. Its a bit cheaper.

My engine.... 4.6 with 4.0 pistons, real steel typhoon cam, 500 heads, decat, blended trumpet base, 72mm plenum and megasquirt. Gave 275 @ wheels on 95 ron petrol (V-power sold out due to panic buying).
Add some nitrous.... 418bhp and 440lb/ft for 0-100 in 7.5.
Love the use of past tense.. 'gave'

How is the rebuild going ?
This is on the engine I am running now.... ex Haircutmike, ex Brummmie.
'Gave' simply refers to the NA run on the rollers last Friday. 312 NA, then 418 with gas.
Ive ran a 12.4 @ 111 on this engine without gas. Its a good 'n smile

ETA.... most of the 'old / new' engine is sat in a box waiting till i get round to delivering it somewhere for further inspection

Edited by dbv8 on Thursday 5th April 09:43

robrover

41 posts

176 months

Monday 9th April 2012
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Transmitter Man said:
Rob,

Any actual flow data to hand?

Phil
Hi Phil
The Buick 300 heads were originally modified on a flow bench by Holden/Ford V8 head guru Eddy Woods at the Head Stud Development Co in Melbourne, and they were originally destined for a 5.0 litre Leyland P76 motor that went into an extensively lightened LC Holden Torana drag car (this was well before alloy GM LS engines became available).

They were later welded and re-flowed locally by Air Flow Developments and now flow 193 cfm at 550 thou (1.75 inlet). Standard P76 was about 132 cfm at the same lift (P76 heads were the same as the early Rover P6B heads). I think the later post 1976 SD1 Rover heads flowed about 148cfm at the same lift, with Stage 4 Rover heads around 181. Stock 300 heads flow 153 cfm at 550.

I believe Merlin F85 heads can be maxed out to flow about 185 cfm.

The inlet ports on my reworked Buick heads were much bigger than the Rover heads, so much taller that the inlet manifold had to have the roof of its port flanges welded and ground out to extend them upwards, then reshaped to match the cylinder head ports. I used P76 head gaskets with the ports opened out (the 4.4 Aussie engine had taller deck height than the Rover).

I believe Lanocha in the US has flowed over 200cfm from Buick 300 aluminium heads which was sufficient to support 425 hp on a maximum-effort, high-compression, normally aspirated 5.0 litre TR8, and that’s using a single-four-barrel Daemon Racing carb on a Huffaker open plenum inlet manifold, not efi.

This site provides some useful flow comparisons
http://www.british-cars.org/mgb-gt-v8-technical-bb...

Rob



Transmitter Man

4,200 posts

184 months

Monday 9th April 2012
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Hey Rob,

Very interesting stuff written by Dan Jones in the US.

I purchase some new CHI heads from the Aus factory and had them shipped direct to Dan in the US who wanted to use them in his Ford Cleveland dyno shootout.

These are now sitting in one of my cars on a 408 Cleveland stroker.

Have you sorted an off the shelf or custom ground cam for the Buick heads yet?

Spec's?

Interested in hearing about the numbers on the dyno when you're done.

phil

Else

Original Poster:

781 posts

198 months

Monday 4th June 2012
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Nearly there, just got to make up an air filter box and the pipe work.