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18 minutes ago, TRTOM2498PI said:

Hi Jon,

Are you building a race engine ?

Steel rods too ?

I would say more "very fast road" rather than race. I want it to not be an intractable pain in the bum but have it when I want it.

I have +60 forged pistons and rods on the shelf ready to go. It will be a big valve head and Newman PH3 cam. I would like to be able to safely hit 6800RPM which is well below what an all forged bottom end can handle and on the upper limit of a modified standard crank. I'm right on the point of making a decision about the crank. It's a lot of money and I'm taking some time to think carefully about what I'm trying to achieve.

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8 minutes ago, FatJon said:

I would say more "very fast road" rather than race. I want it to not be an intractable pain in the bum but have it when I want it.

I have +60 forged pistons and rods on the shelf ready to go. It will be a big valve head and Newman PH3 cam. I would like to be able to safely hit 6800RPM which is well below what an all forged bottom end can handle and on the upper limit of a modified standard crank. I'm right on the point of making a decision about the crank. It's a lot of money and I'm taking some time to think carefully about what I'm trying to achieve.

Hi Jon,

Sounds like we are on a similar page.  My current motor is a later ribbed block, 0.040" bore, Mahle pistons, Carrillo rods, lightweight steel flywheel, Newman hybrid cam, EN40 steel followers. Line bored block, PB cylinder head, different valves and TT double valve springs. Crank, crank pulley, rods, pistons, flywheel and clutch cover balanced at Vibration Free. ARP head kit & flywheel bolts. TLE exhaust manifold and 2.5" exhaust system.  I have ran it like this since 2011, and 80-90k miles at present. The engine revs beautifully to 7000 + RPM, without even trying or sounding harsh or thrashy, it just thrives on it. the point here is, I still run the original crank.  The revs I use are based on an accurate electronic STACK tacho.

 

I have since had it converted to EFI (5 years ago), and planning a new engine later this year. This time with a Newman PH5 cam (which I have already purchased, & new steel followers from Newman).

I know someone who has recently had a 2.5L engine built on webers, with a Newman PH3 cam, & he said it is very tractable, but noticeably more powerful over 3000 RPM, compare to his EFI 6, which has a Newman PH2 cam, as a comparison.

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21 minutes ago, FatJon said:

I would say more "very fast road" rather than race. I want it to not be an intractable pain in the bum but have it when I want it.

I have +60 forged pistons and rods on the shelf ready to go. It will be a big valve head and Newman PH3 cam. I would like to be able to safely hit 6800RPM which is well below what an all forged bottom end can handle and on the upper limit of a modified standard crank. I'm right on the point of making a decision about the crank. It's a lot of money and I'm taking some time to think carefully about what I'm trying to achieve.

What gearbox are you running ? I see you have the Quaife rear hubs, so I know all is well in that department.

Edited by TRTOM2498PI
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2 minutes ago, TRTOM2498PI said:

What gearbox are you running ? I see you have the Quaife rear hubs, so I know all is well in that department.

You are converting me on the steel crank. What did you do it, if anything, in terms of toughening, lightening etc? I read an article by Kas Kastner in which he intimated that the flywheel is the key to the crank problems. Reduce the weight of it considerably and the engine becomes a lot happier and less inclined to grenade itself.

If I don't buy the steel crank I will go with the MX5 gearbox conversion. I have used one of those on my 300+hp Exocet and it's bulletproof. I also love the slick change of it. If I did use a steel crank the MX5 box is well out of budget.

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9 minutes ago, FatJon said:

You are converting me on the steel crank. What did you do it, if anything, in terms of toughening, lightening etc? I read an article by Kas Kastner in which he intimated that the flywheel is the key to the crank problems. Reduce the weight of it considerably and the engine becomes a lot happier and less inclined to grenade itself.

If I don't buy the steel crank I will go with the MX5 gearbox conversion. I have used one of those on my 300+hp Exocet and it's bulletproof. I also love the slick change of it. If I did use a steel crank the MX5 box is well out of budget.

I just had it balanced, with nothing else done to it. It has been fine, and been zero trouble. I think it when things are not balanced, or there is an issue with the crank damper with the use of high revs, do you get issues.

I have a lightweight Bastuck steel flywheel, it was then balanced.  

Gearbox: You will be fine with a carefully built Triumph Stag derived gearbox, with a competition o/d unit. This will absorb over 200bhp & 200lbs ft torque, and you will be able to engage o/d at wide open throttle at 6000 + RPM without complaint.  It is quite entertaining. It is as close as you will get to a sequential gearbox. Worth using the clutch to disengage the o/d though.

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12 minutes ago, TRTOM2498PI said:

Gearbox: You will be fine with a carefully built Triumph Stag derived gearbox, with a competition o/d unit. This will absorb over 200bhp & 200lbs ft torque, and you will be able to engage o/d at wide open throttle at 6000 + RPM without complaint.  It is quite entertaining. It is as close as you will get to a sequential gearbox. Worth using the clutch to disengage the o/d though.

or 5 Speed LT77....I am very fond of this. Rated 245 lbsft and fits well to my 190 BHP engine

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22 minutes ago, JochemsTR said:

or 5 Speed LT77....I am very fond of this. Rated 245 lbsft and fits well to my 190 BHP engine

The lt77 is interesting as I have one sat doing nothing. Is there a bell conversion or backplate on the market or is it a mix and match job?

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