Some more Times 2V

[Anonymous]

Execute.
Thanks for comments. I didnt realise that a 5.8 ltre Falcon would have trouble beating a 8.5 0-62 mph second time. Im pleased with this.
After you recommended trying 4400 rpm instead of 4000 rpm changes I thought I would try it last night (with the leaking seal)
Before I went I checked the timing and because I have moded the xf elect dizzy to fit the 2V block the side clip was hitting it and forcing it r it to turn to further advance gave a noticable improvement in power and smoothness (Ill have to fix this properly somehow).
I then took myself 110 kg and my 250 2V Cortina (1150 kg in owners manual) and a quarter of a tank of fuel.
First time was 8.62 0-62 mph exactly as before. But 8 inch rear tyres had lots of spin in first and a bit in second.
Had to feather clutch very gently out and floor it to stop it spinning to get 8.42 sec time and another 8.41 in third gear. No bogging at all this time.
I will go up in jet size if 74s in 500 if 74s are holding me back as you suggest (what size whould I need if I had 220 hp 78 or 82 I wonder?).
Your figure of at least 155 hp at the flywheel to get 8.5 concures well with guy at Hume performance who had a 250 2V mild cam and 500 holley he said his made 124 hp to rear. Still good but a long way shy of 147 kw (at flywheel) that Dick Johnson said is possible (from one of your previous postings). That was said to be with a sub 270 degree cam and 500 holley with slightly moded alloy crossflow head. 115 to 120 kw to rear with same mods Ive got in a crossflow is nothing to laugh at.
Who needs a dyno with you around.
Regards
Thanks Heaps, Cheers

 

[xctasy]

As soon as you climb over the 48 call size jet , the relationship of jet to thousanths of an inch jet hole size changes. A 49 jet is still 0.048", a 74 is actually a 0.081". An 82 is a is a whooping 0.093", and a 100 is really a 0.128" hole.

Jet area goes up massively with each call size number.

a 48 is still technically 0.001810" square in area
a 49 is still a 0.001810" square in area
a 74 is 0.005153" square in area, stock size for ~ 135 flywheel hp
an 82 is 0.006793" square in area, 31.9% bigger than the 74, ok for a
a 100 is 0.012868" square in area, almost 150% bigger than the 74.

Since there are two jets on a #2300, the jet area goes up massively. 350 hp is technically possible with the big 82's in a 350 hp V8 sucking huge vacumm rates at wide open throttle, if this is to be believed.

http://www.einfo-net.com/motorsports/brz/spacers/114-dyno.jpg

( found at http://www.einfo-net.com/motorsports/brz/spacers/adapters.html )

This is about where I get lost. There is little info on jet settings here, and guys are into special fuels, often alcohol. The jet size for a full house gasoline 250 2V could be up at the 82 mark, but I'm not certain....yet!

 

[Anonymous]

Just for the record to anyone who happens to doupt me I know 8.62 and another 8.62 sounds like I fudged the figures (I did not) and also a 8.41 and an 8.42. Actually I did get a 7.38 but choose not to include it as it was not consistant with the others. The 7.38 was a 0-59 mph time I think I may have let it rev a little higher avioding the last gear change to third.
Keep in mind that with a cam that peaks around 4600 4800 I could aviod the change to third and pull at much higher rpm through the last part of the dash. I think this would make a significant difference to the times.
I am now wondering with the right gearing, cam (not too hot) and a crossflow if it would be possible to get around or close to a 6.5 time. WRX territory. Even a 7 would be great.

 

[xctasy]

The way to get into the sixes is to get enough power to do 14.2 second quarters!

If you could get a little over 205 hp at the flywheel, you'd be there.

That's just a good 500 Holley, a good cam, and the sort of head you have now, or a XF pakage spec'd out to handle the lift.

 

[Anonymous]

Execute, all the cams I have looked at (many) consistantly across the board offer higher lift for an equivalent in a crossflow than in a 2V.
For example a 270 cam .450 lift in a pre-crossflow will be offered as a .510 lift 270 cam for a crossflow by the same company. Just a casual observation Ive made.

 

[addo]

I know what you're saying. Crow are good example; their grinds are identified by the last three numbers - ie, 666, 613, 770...

The only way around that is to bench the head, and come at them with RPM operating bandwidth, and flow specs in 50 or 100 thou increments to 0.600 or so. I feel that they are conservative in recommendation (how many people have lost an engine in these forums due to valve float?) and also based on the non-2V design.

Those tall cams put a lot of stress on the timing set. A JP gear drive may be in order. Or, go back on the cam and turbocharge. Dollar for dollar, that may be the most interesting tack, especially then with TBI or a custom fuel rail and injector bosses added. You'll add power, drop the bandwidth and extend engine life. (Noting that it seems your rings may have not seated nicely in the current rig.)

BTW, I think your motor was pretty cheap if you got the whole longie for 3 and a half.

Adam.

 

[Anonymous]

I used cro-moly rings because I have had some experience with this material and it is "very tough" especially compaired to cast rings.
Possibly it doesnt bed in as well as I pressumed it would and I may have driven my car too kindly for the first 1000 in hindsight. Ive read that to run in a volks wagon engine its recommended to take them up a steep hill at WOT a number of times before 1000 clicks is on the engine.

 

[Anonymous]

I learned with my engine than youve got to trust the machinist (all the more so if you know next to nothing).
I first took my head to a reputable workshop through a mechanic who has had a lot of work done by them over the years. When eventually paid for the "finished" fully reco 2V head was taken home and handfulls of sand was found to be pouring out of the water jacket holes. Not knowing a lot I pressumed this would not be good for the engine so I took it back. After many days of phone calls I eventually was told it was fixed and I could pick it up. At home more sand was still coming out of it easily about a quarter of a cup from memory.
I took it back again. Day after day I called until eventually they said it would be done the following day at an arranged time. I arrived to find it was still not done, they then blew the sand out with high pressure while I watched and waited (took about 5 minutes).
After this I started to have second thoughts about getting this machine shop to do the rest of the engine. It was a good thing I did because without saying anything of my experience with them my new machinist rang to say that this head would need three of the valves on the head re-machined.
I concluded that if this is what a highly regarded workshop does when a rare 2V head (the guy at the counter knew what it was) is given to them to reco through a mechanic they have done a lot of business with for at least 15 years then what to they do to other engines and one off jobs. I shudder to think.