4L

[lyonsy]

so has anyone played with 4L sochs/dochs on here yet.
can you buy soild roller arms ?
benifts over crossflow from what ive seen is bigger ports standerd about 39mm which is about the limit of ported xflow head iam lead to beleave.
ohc is a bit better to and the standers valve springs will take over 6000rpm.
is the block much stronger the crank is about the same.
does the 250 pistons with 200 rods bolt in or can you use the later ba ones which have been teflon coated?
oh ill most likly be running carbyd at first then go injection.
just looking at the next engine build after ive had the head on the 250 ported.
drift

 

[aussie7mains]

Haven't your parents taught you any grammar, spelling and punctuation?
Anyway the OHC is to my mind vastly superior to any of the earlier sixes, this especially applies to the AU VCT (I have one):-
The crank has considerably larger mains and is better balanced.
The rods are longer.
The block is as good as any of them.
The sump is cast alloy and supports the main caps, which are further supported by the addition of a steel support frame bolting all caps together.
Even the exhaust manifold is quite efficient.
The engine has advance and retard on the camshaft, it has its own cam.
The valve train is low inertia (read as lighter).
The VCT is rated at 172kw on unleaded, which is within a hares breath of the V8, it will run to 5500rpm any time.
Overall I wouldnt even bother with any of the pushrod engines even though the OHC will be a little bit more difficult to adapt carby type systems to (why bother) .
They are turning up here in perth for less than $1000.
Get yourself an AU enine, fit it with a Wolf or something like that, fit a good exhaust, change the cam, Crow do have them, go racing.
A7M

 

[gassed250]

Haven't your parents taught you any grammar, spelling and punctuation?

Who cares its not a bloody english test is it

And you still knew what he ment, so it was a waste of time even writing that

 

[xctasy]

Xmas cheer, brothers.

As for da speeling, I aint no good either.

I'm with A7M. The guy spells better, and makes sense. Why I work on I6's is that OHC gear is overpriced, and introduces more problems than it solves.


Drift, your on the right track with better components from the OHC, but the best option is to go the OHC first.

The fact remains that for Australians, an OHC is the only REALLY SENSIBLE I6 game in town, but there are issues no-one is dealing with. Sumps?
US gearbox adaptors?
integrational work needed to customise it?
No-one has done anything but name drop like a music critic!


For Americans and those with pre 66's or non Falcons, there are 300 missing parts to screw up a great OHC plan.

For those of us who have had to ship over seas becasue there is no dealer support , the following are insurmountable:-
the ignition,
bearings,
cams,
gearbox,
starters,
flexplate,
flywheel,
bolts,
rocker gear,
gaskets,
electronics,
space issues regarding the sump on pre 66's and most X-shell US CARS and the amazing ability for any one of the above to conspire against you.

Dancing kniting needle engines will be around us long after the DOHC engine has become an alloy I6. There are 20 million 200's in the US, and 4 million in Australia, even if a few are boat anchors. There are only 1, 2 million OHCS, 500 000 of which are AU-onwards. They have zreo % parts intecahgne with any OHV engine.

The X-flow has a 95% commmon parts share with the US and Aussie non cross flow 200 and 250's and the valve gear parts are basically 351c/m/400/Chevy 396/Ford Lima 370-429-460.

Again, the reason the OHC's won't grow in popularity is the lack of sumps, US gearbox adaptors, and integrational work needed to customise it. Everyone knows that just a 1988 EA MPI can outrev and kill any 250 X-flow or 2V, and that a turbo DOHC is okay for over 600 hp with mostly stock parts with few modifications, and 1500 hp with better cranks, rods and pistons and some cylinder support.

 

[lyonsy]

yeah its about what i was thinking.
the class iam running the ohc engines do make slightly more hp but dont seem to make the torque the xflow can make and being speedway torque is better then hp in a lot of cases.
but as ya said sump is killer as i need a rear resivor but there ant one so gotta make one.
no aftermarket suport for n/a and little for turbo.
also a drop in capcity is never a good thing even worse when is bore in long stroke small bore engine.
as for rev better they just make more power up high due to larger ports ive seen more failures from ohc engines at 8000rpm then 250 xflows.
so does anyone make a soild roller rocker rather then the hydrolic roller they have standerd?
drift

 

[xctasy]

Merry Xmas


You have to fit Cleveland or Windor rollers and make a custom cam to suit. Crow did make a design for roller cams way back in 1990, but never released it. The cams were made fro a Texan called JD, according to Ray Spencer.

Basically, the tie rods need to be the right modular width, and the cam needs to be custom ground. Any Cleveland or SVO Windsor with A3 on wards (AlloyHi port versions of the old Boss/Cleveland head) have a cheap master profile from which you can get the ideal profile.

It's just a matter of money. The OHC's now have most of the development focus thses days, but the market is still the X-flows because everyone is tryng to get rich on cammers, without helping people answer the real issues...sumps, gearboxes adaptors and carby/injection interfaces. All the profiles exists in abundance, but no simple gear is built around the ohc, so people use X-flows instead. Shame. A good ohc is a brilliant engine.

 

[lyonsy]

sorry i mislead ya.
do they make a soild roller rocker arm for the ohc instead of the standerd hydrolic roller.
as these tend to fail with high lift high rev engines in the ohc.
ive also seen a few modified production engines putting in excess of 220rwkw n/a but i know of one that has blown up 6 times in one season due to sensor's failing.
btw the guy who owns that engines only uses the best parts engine builder that money can buy.
the xflow is just so reliable that a lot of people dont want to move away from it when ya see stuff like that happen.
drift