XFlow cams - between a 234 and 244

[OliverSedlacek]

Some time ago I 'upgraded' my 1700 XFlow from a Kent 234 cam to a Kent 244 cam, but I've decided I'm not actually that happy with the results. I get more power, but the engine now comes on cam at over 4000 rpm instead of 3000 rpm. The engine is also distinctly lumpy at 30 MPH (1700 RPM in 4th), so I was wondering what my options are. Now that I've got pockets machined in the pistons, I'm looking for a cam with the lift of the 244 but with the timing of the 234. Does such a thing exist?

[6speedmanual]

Who makes those cams?

Go and ask them if they can grind one for you from a blank or from a standard cam if they are regrinds.

Someone in their drawing office should be able to say.

 

Peter

[elie boone]

What dizzy are you running, the original ? if you change to an Aldon one there is a big difference in smoothness. Well worth the extra cost or if you have more budget go for a 3D ign thats even better and returns much improved mpg.

[dalongbloke]

Dear 6 speed... I think Kent cams make the kent 234 and Kent 244

 

Edited by - dalongbloke on 21 Oct 2011 09:13:04

[Dignity]

Quoting dalongbloke: 

Dear 6 speed... I think Kent came make the kent 234 and Kent 244

 

Yes but who makes the Kent 239?

[dalongbloke]

That, dignity, is the best question so far! Andy

[OliverSedlacek]

I'm running a Megajolt (mapped 3D) ignition system. I've been advised to retard the cam timing, which sounds like it's worth a try on cost grounds.

[6speedmanual]

Errrrr - yes! It was a rhetorical question. I'm familiar with the company having had a special made by them. They were able to tweak the timing significantly.

 

If they are having "new" blanks manufactured, the possibilities are vast. If carving a new lobe out of the material in the exisiting lobe of a standard cam the scope is narrower.

 

Having said that, just pulling the timing may not totally give what Oliver is looking for. A cam with the same lift as a 244 but timed as a 234 may only produce approximately the same power as 234. Depends on various factors as to what is limiting the power at various engine speeds.

 

That is why a conversation with Kent Cams may prove useful.

 

Peter

[George C]

I have had the 234 and 244 cam. I know what you mean about the 234 cam as it has good torque characteristics. The 244 cam will work fine if everything is in order. An ignition upgrade does also add back torque at low revs. I run a MBE 3D ignition system and with the 244 cam I have more low down torque than previously with the 234.

 

I have also used an A6 cam which is a long duration cam and gives similar power to the 244 but if I were you I would stick with the 244 and consider an ignition upgrade. You also need to make sure cam timing and everything else is OK.

[cskip]

Have you had the Megajolt mapped on a rolling road or are you using a default map?

 

When I was running a 1800 xflow with a 244 and megajolt I used a map from the internet. It didn't run very well. The map was very conservative. After a session on the rolling road the improvement was amazing. 😬

[millsn]

Pal used to have a 1700 with 244 cams. It ran fine, wasn't rough at all. It is resolvable

[Graham Perry]

When I was upgrading my 7 about 15 yars ago I asked my engine builder to fit the 244, but he wouldn't do it as he had had customers with kit cars whom were not totally happy with it. Instead he retimed the 234 to give more revs and to be honest I was happy with that at the time. We did add 3D though which made the bottom end of the rev range a whole lot more tractable.

 

Now running a Cosworth A6 after having a succession of expensive Kent cam failures, and have been very happy with it.

[Revin Kevin]

Oliver,

I agree with all of the above, particularly with getting 3D ignition and critical that is mapped to your engine.

As for the 234 cam, if you retard the timing by 2/3 degrees it tends to give a bit more at the top with little loss low down all things being equal.

I previously ran a 234 cam but wanted the opposite IE it to hold onto the power a little longer at the top. I achieved this with a very well ported head but not with overly big valve sizes but a 244 cam. From my experience the porting is far more critical than valve size and you get what you pay for!!!!. This engine will pull cleanly from 2.5k/3k all the way to above 7k. I still run conventional ignition so 3D should help a little more if I ever get round to it. This engine pulls as well as a 234 low down and not far off as good as a 244 at the top.

 

Cheers

Chris

[OliverSedlacek]

Thanks for all the input I'm going to stay with the 244 and time it a few degrees later. I haven't mapped the Megajolt yet as I'm still unsure who to get to do it.

[Revin Kevin]

Oliver,

retarding the cam timing in theory will promote top end at he expense of bottom end.

 

Chris

[eric]

If you use the 7 mainly on the road The 234 is better than a 244.

It depends also who will make the engine .... porting the head, balance etc...

 

Lot of differences beteween a good and a bad job !

 

[andy couchman]

Hi Oliver

 

I have a1700 with Kent 244 cam, Jenveys and an Omex ECU. It has quite long bellmouths on the TBs, which I think may help too (see back page of this month's Lowflying). Internals are standard apart from lightened flywheel and forged pistons.

 

The car is very tractable at 30mph in 4th (top) gear (even down to about 25mph) and seems to produce good power up to its peak of 147bhp at 6,416 rpm (roughly 😬). Max torque is 127 ft lbs at 5,700 rpm but only just behind that at 2,500-3,000rpm (with a dip between 3,000 and 4,500rpm) i.e. still over 120 ft lbs. That was on a RR that has a reputation for not overstating power (Mech Repairs in Cheltenham, and the engine was mapped by Omex MD Richard Wragg).

 

Hope that helps as a benchmark when you get it RR'd.

 

With that set up, Chris Alston (1700 Zetec) and I set identical 1/4 mile times at this year's Brighton Speed Trials so the ol' crossflows can still produce a reasonable turn of speed.

 

Andy

[Drumster]

They certainly can as mine is actually a 2.0l Zetec on carbs 😳

[andy couchman]

Sorry Chris! Slip of the brain...

 

Andy

[eric]

My race engine builder, is more tempted for the 234 than the 244 but with a good work on the head not specially larger valves than a stage 2.

 

I will rebuild my AX block in rebored at 1760 cc with a 234, forged pistons, steel conrods and crankshaft, compression ratio : 11.5, Steel flywheel

[McBreadhead]

Eric,

 

I wish you could try my 1760 xflow which has a stage 4 race head with a Cosworth A6 cam. It is very tractable and pulls like stink from 3,000 rpm all the way to 7,500rpm. The A6 is very well suited to this engine and my engine builder set it up for road use and good spread of power and torque across a wide range of revs.

 

We got 165bhp at the flywheel on the rolling road which is a very good output for road use.

 

McB

[George C]

My experience with 234, 244 and A6 cams is that they all work really well. The most important thing is the person or company building the engine and getting the overall package right.

 

What has amazed me in my latest spec rebuild with the 244 with more porting, bigger carbs etc etc etc is that it now has better low down torque than previous specs. This I believe is down to some more modern engine building theory and the 3 d ignition. Start it from cold and it will just tick over smoothly etc.

 

The only downside of the modern technology is that the engines are now so tractable that they dont have the pronounced increase in power when 'on cam', they just seem to work through the rev range. I miss this a little but I like the characteristcs of the modernised engine.

 

So I plan to upgrade to 254 to make the engine a bit more peaky. One word of caution is that the new cams available seem to have a very high rate of failure and so its better to find an old one if you can.