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Posted: Wed Dec 26, 2012 5:13 pm
by DaviesDJ
hi guys, am at a cross roads on this topic and need some help! am considering buying the 300 Buick heads (from this forum) and heavily modding them welding chambers and fitting bigger v
Alves. the plan for my 5.0 block in my landy is to improve the performance without NOS - and use nos for the big power - 50 shot now working well, transmission upgrade on the horizon. want the fastest defender in the uk. Have stage 3 rover heads currently. But the other alternatives to the 300 for me are 1) taking a good set of rover heads and putting stage 4 valves (je race size) and porting them non cNc. 2) going for ported merlins. 3) JE stage 4 - although these are a bit pricey - don't thik wildcats will suit my app,citation and the mods to the inlet and exhaust put me off. which would you go for? Have a griff 500 cam and Eddie 600 carb with performer manifold. how much does JE want for ported merlins I wonder? Would a professional hand finished porting be a million miles off CNC? how hard is it to bring the compression ratio of the 300s to usable spec? Sorry to hijack the topic, but am so tempted by the merlins, but could work on 300s over time etc.
Posted: Thu Dec 27, 2012 6:11 am
by minorv8
CNC heads are supposed to be better but remember that they are first hand ported and then digitised and data converted to computer code that CNC machine uses. So, the final product is only as good as the original port.
The real benefit is that each port is equal to eac other as well as each head is equal to tje others. Reproducibility is superior to the hand porting.
I believe for Buick 300 heads you need to take into account the welding, possible heat treatments before and after welding, most likely loose seats that are best replaced aldeady before welding, new ones put in, new valves, machining and porting. I foubt that they really are that cost effective.
Ported Merlins sound interesting, would love to see what Eales have managed to do with them.
Posted: Thu Dec 27, 2012 7:45 am
by mgbloke
Eales is definateley NOT a fan of the merlin heads and only has negative comments about them!
Posted: Thu Dec 27, 2012 9:01 am
by DaviesDJ
I know he is not a fan, I had a conversation with his wife who was profoundly negative about them, surprisingly so in fact. They cant be that far off his cNc ported heads surely?? How much does be want for them
I wonder. Think there are too many question marks with the 300 heads for my application!
Posted: Thu Dec 27, 2012 10:53 am
by JP.
Somebody calling my name
Yes, running those Merlinheads for years now on our 3.5.
Have them from the first batch when they came in two chamber sizes ( cc's).
While Real Steel does advise them not to run on a NA 3.5 they told me I could run them cause my roots supercharger. Have to say they even work on a NA 3.5 as I onetime had to leave my blower at UKblowers for repair during a trip through the UK. He made me a baseplate to run my carb straight on the blowerintake to get on with my holliday trip and even get me back to Holland.
We where all very supriced how smooth the engine was running that time.
Did put those Merlin heads on the engine straight out of the box when I got them. Never bothered about them them eversince.
We inmidiatly experianced an improvemend over the stock non modifiet SD1 heads while driving the car. Dyno did show way better figurs also.
Specs:
3.5 RV8 ( SD1)
Merlin heads ( 9:1cr calculated by Charles from real Steel))
Viper Hurricane cam with Rhoads lifters
Blower intake by UKblowers with Magnacharger 110 running 10psi boost
Custom made Holley 570cfm.
Basicly we build the engine just how Charles (Real Steel) and Nigel (UK blowers) told us to do at that time and never bothered about it eversince.
Its still running great and as there allways is some bloke that will be quicker (endless story) we never bothered to build another engine.
Sorry we dont throw horsepower figurs.
Posted: Thu Dec 27, 2012 1:15 pm
by Wotland
Well since the business exists : If you want to succeed in business, always say that the products of other sellers are the worst in the world, your own products the best in the world

Posted: Thu Dec 27, 2012 1:29 pm
by Wotland
JP. wrote:Somebody calling my name
Yes, running those Merlinheads for years now on our 3.5.
Have them from the first batch when they came in two chamber sizes ( cc's).
While Real Steel does advise them not to run on a NA 3.5 they told me I could run them cause my roots supercharger. Have to say they even work on a NA 3.5 as I onetime had to leave my blower at UKblowers for repair during a trip through the UK. He made me a baseplate to run my carb straight on the blowerintake to get on with my holliday trip and even get me back to Holland.
We where all very supriced how smooth the engine was running that time.
Did put those Merlin heads on the engine straight out of the box when I got them. Never bothered about them them eversince.
We inmidiatly experianced an improvemend over the stock non modifiet SD1 heads while driving the car. Dyno did show way better figurs also.
Specs:
3.5 RV8 ( SD1)
Merlin heads ( 9:1cr calculated by Charles from real Steel))
Viper Hurricane cam with Rhoads lifters
Blower intake by UKblowers with Magnacharger 110 running 10psi boost
Custom made Holley 570cfm.
Basicly we build the engine just how Charles (Real Steel) and Nigel (UK blowers) told us to do at that time and never bothered about it eversince.
Its still running great and as there allways is some bloke that will be quicker (endless story) we never bothered to build another engine.
Sorry we dont throw horsepower figurs.
RS told you why you can't run this heads on NA 3.5 ?

Posted: Thu Dec 27, 2012 4:03 pm
by JP.
Wotland wrote:RS told you why you can't run this heads on NA 3.5 ?

They flow to much, they sayed a 3,5 won't have enough capacity to create enough vacuüm to create a continues flow of air.
They sayed as my roots blower is pushing air in all the time, I had no concerns.
I think a Holley 390 (vacuüm secondairies) will work with Merlinheads on a 3.5.
I guess, quad Webers will cause serious issues on a street orientated 3.5 with Merlinheads.
Posted: Thu Dec 27, 2012 5:45 pm
by kokkolanpoika
I´m NOT a fan with Merlin´s. I install my Friend engine those J.Eales STD merlin heads, ported +300£ + vat more expensive.
J.Eales say ported Merlin heads flow approx 1cfm less than his CNC heads and same engine with same cam it will give 6hp less than his CNC heads..
STD heads will flow approx 8cfm less than his CNC heads. I have got his flow test data with my e-mail..
And our local famous head ported say when i made flow bench testing my own poor ported heads vs Merlin heads. Why to hell they are fabricate bicycle agin.

Only good what he can seen those heads are consumption chamber and shape of exhaust port, it is slightly better shape than rover, but flow less than ported rover. It is raised approx 6mm.
We do not make flow testing those when i modify those ports. But he estimate that inlet would not flow mutch better if you port that silly corner away, only gas speed will drop, whitch is better, because those ports are far to small that size of valves. Need to be opened to rover stage 4 specks..
Also exhaust port need to be opened to rover stage 4 specks. Then it might be flow as ported rover ext port..
Valve shape is very poor with merlin´s and too heavy valves and stem diameter is far too big also.. Budget heads..
If i have to buy set of heads, i will buy buick 300 or P38 heads, slightly weld aluminium those port´s floor and maybe outside of the head to get good shape? 3-6mm more to floor..
I would not weld consumption champer, mutch better to use flat top pistons with good big consumption champer.. More quench..
You might get 10-20hp more with flat top pistons even with boosted..
Posted: Thu Dec 27, 2012 6:01 pm
by JP.
Yess Kokky, we all know what you think about Merlin heads.
In Finland everything is better.
Blablablablahhhh
Please M8 tell us something new as I am getting a bit tired of it.
Posted: Thu Dec 27, 2012 7:09 pm
by kokkolanpoika
Please tell us JP more impressive dyno runs of Merlin heads if they are mutch better than rover´s.. Same as wild cat heads.. Ever seen any near 400hp readings of merlin heads or wild cat heads.. Merlin heads are sold hundred of pieces.. So there must be over +5.0l engine, TVR or tuning shop engines..
As minor v8 say they are worth of extra 11hp.. What about J.Eales CNC heads with same engine? Worth same 11hp or more? As Minor rover heads are home ported with 41.5/35.5mm valves. What would be hapend if you increase valve size those heads? In my mind this porting is good and Jukka know´s what he is doing..
Those heads what i fit my friend engine, another head inlet valves will sit different height, approx 1mm same head.. Head gasket mounting face is not straight, machinist say it is machined too high speed and then blade will jump.. Inlet port floor is different height same head.. approx 2mm.. Valve seat matching to port is very poor, similar like stock rover.. Port is bigger than valve seat another side of port.. So it will resist air flow.
Why not cast good parts if you want to make those? Same job, same time, same price, and better results and happy customer.
Posted: Thu Dec 27, 2012 7:58 pm
by minorv8
I am from Finland too but I doubt that things are better here. Winters are too long so we tend to have too much time thinking about ... Well whatever.
I think Mark had pretty common heads before fitting Merlins. I thought that mine were not that special, only around 275-280 hp mark on 4,6 bottom end. I tend to port quite conservative. Hate to break into water gallery... Been there done that with Mini heads.
Anyway, the difference was quite small but if compared to std heads it would have been bigger. My cam is mild due to certain legislative issues, i simply can't fit a cam like what Timo has. It would be interesting to see what the heads could produce.
I believe Timo has reached quite close to what is possible with Rover heads. Std or ported Merlins would probably give nothing. Even Wildcats might not improve things unless willing to go to race spec cam and loose street manners. Ditto with TAs, they look promising but there are very little hard facts available. With next to nothing info from TA About the head specs it is hard to even guesstimate just how good they are.
One more thing, Rover heads have been around 40 odd years and they have been ported in thousands. Merlins are a limited number in comparison and I don't think that it is fair to say that they are crap. I doubt that mr. Eales has explored the limits of the castings. It is quite expensive to dig holes on a pair of 1000+ quid heads so you can squeeze the last bits of flow.
I recommend that you get your hands on Mr. Vizards latest book on head porting. How to port and flow test cylinder heads, printed in 2012. Decent book but seems like he is full of himself. I still have not finished that book... but if one skips the "I am really good at what I am going" stuff it is a good book. What I would like to see and read is fair estimate of heads and workmanship. No bad mouthing of competition products.
I do agree with Timo about the quality of casting. The ports are not equal and I did some porting to balance them but could not fix everything. I don't agree about the port corner. It will create a hell of a swirl and turbulence in the port, not speed up the flow. I would love to port the intake and exhaust further but I do not know the thickness of the ports and do not want to find water galleries.
My ports are now the size of the factory gasket, I have never seen any stage whatever heads so can't compare how big those ports are. Maybe I just have to stick a bigger cam in the engine and see how it performs.
merlin
Posted: Thu Dec 27, 2012 11:29 pm
by little tub
according to RS, JE has only purchased one pair of heads, i have been told JE builds fantastic engines and obviously knows his stuff but competition/personal vendettas etc must influence his comments, which is only natural, he told me he had piles of merlin heads that he cannot give away, which has been proven as a lie because i got my friend to call him, asking to buy a pair of merlin heads but he was told by JE ,he didnt have any in stock at all.
Also JE said he could not fit an injection system to the merlin heads because "it will not work ".
I have nothing to prove or argue about or compete against, i will post honest dyno results and if you lot tell me my figures are crap i will do something about it.
Cheers

Posted: Fri Dec 28, 2012 7:56 am
by kokkolanpoika
I order those merlin heads from JE to my friend approx February 2012.. He has got STD pair and ported pair for sale.. Both heads has been approx 2h on dyno. Both run his cross over inlet manifold.
When i fit those heads on my friend engine. Inlet port floor is approx 3mm higher than STD 4.6EFI manifold. So if you want to make good kit, you have to weld inlet manifold floor to rise it.. Porting head floor is not a good idea at all.. Not sure for carb manifold..
Posted: Sat Dec 29, 2012 9:28 am
by DaviesDJ
Now I am no expert, and not even an authoriy but it seems to me that if both the merkin and rover heads started out life along side each other and had equal production runs and were now available an roughly the same price and in similar quantities then the merkin heads would probarbly be far preferred / superior. We simply cannot experiment and develop with these limited run castings so we will never know. Cost is such a major factor though;-) I think if we all had the money - we would order wildcats. But if merlons were made in higher volume then Could they be developed to be the head of choice? I know the CnC rovers are a force to reckon with but the only reason they don't turn me on is they represent a dead end of development.