70 replies to this topic

[LXCHEV]

Hi guys,

Machine work is done, I need to buy a cam!

What are your thoughts on this hydraulic roller from Crane? (part # 119581)

It's a 238/242 @ 0.050, with 372/372 lobe lift (558 lift with 1.5's, or 595 with my 1.6's) on a 110 LSA. The rest of the specs are here:

HR-238/372-2S2-10.9 IG Hydraulic Roller Camshaft for Chevrolet 1957-1987 V-8, 262-400

I'm worried about a few things:

1. My engine machinist is now hoping we can squeeze my comp up to 10.3 (by decking the heads right back down to 68cc). Would this be enough for this cam?

2. With my 1.6 rockers, is 595 valve lift too much?

3. When a cam manufacture specifies a "cruise rpm", what exactly do they mean. In this case they say the cruise rpm is 3800-4600. I don't wanna have to cruise at those revs to keep the engine in its efficient zone. Am I missing something?

I really do like the sound of this cam though. Just wondering if it's not perfect for my combo (I want perfect cos I'm a fussy bastard!!!!).

[mr5000]

have you thought about going down and speaking to clive cams in ftg he has a heaps bigger selections of cams and hes cheaper to ive already lined up my next cam and the power comes on at 25 or 28 and goes to 68 alot of the crane cams say theres make power to 75 8 82 which i dont no if id wanna be pushing an engine that hard especially a budget built one

[LXCHEV]

Spoke to Clive. Love him for flat tappet cams, but not for rollers! Cam alone was like $700 or something! So I'm going American this time around.

[LXCHEV]

Awesome, thanks Sandman. I have a 3200 stall, so should work well. Can you tell me what kinda things your software reported? If its easier, copy and paste the results into an email, or post it here, would be great to see! Cheers.

[mr5000]

woah yeah id be going american to

[LXCHEV]

No worries that's cool.

Yes, this is my old converter that I've had in the car for years, it's in a TH350. Diff gears are 3.7's.

Planning for plenty of street driving - like 90 - 95% and 5 - 10% racing/car club events. Not a daily anymore, definitely a weekender, but regularly driven, with lots of km's, and yes some highway driving and long trips.

Fuel economy is not the highest concern, but it's gotta be half respectable... I don't want drag car economy!

I'm getting the heads flow tested next week. Once we get the data back, we can then make a more educated decision on camshaft.

[rexy]

Spoke to Clive. Love him for flat tappet cams, but not for rollers! Cam alone was like $700 or something! So I'm going American this time around.

Of course you do get what you pay for and in this case you get the spot on advice from a very knowledgeable and respected cam guy as part of the deal. I know its hard to see the value sometimes but do you really want to guess at it with a young sales assistant or helpline guy "assisting" your choice?
I am biased of course. I am very happy with clives cam in the LS1. I am also very happy with the hyd roller in the 383 plastic. Of interest it has superficially similar specs to your suggested one above. We used 11.3 compression but were using very efficient heads (COME aluminum). Runs fine on premium and has buckets of torque everywhere.

[LXCHEV]

I can see both sides to this one. This is exactly why I'm flow testing the heads, then getting my local guys that I trust to look at the data, and come up with the best cam. We'll then hit the catalogues, and look to see if anyone offers a cam 'off the shelf' that suits my requirements.

The big bonus of course being a SBC, is that the Yanks have spent years perfecting their cam grinds - and there is such a huge variety on offer that I'm sure something will be very suitable. Also, I'm building a 383, which is probably the most common SBC built these days, so the research and testing has all been done for me. Only time will tell!!

Thanks guys for the great feedback and info, it's all awesome.

The latest update on the engine build itself is we're now looking at valves. I decided ages ago that I'd definitely replace all valves - since I broke one, I didn't want to risk the rest. Plus they've done 10 years of work. I'm leaning towards Ferrea 6000 series competition valves - swirl polished and undercut, they look like they'll do the job nicely.

[rexy]

I think my point got lost. There are of course a bazillion more cams on offer from the USA than OZ and if Brett was using someones complete developed combo then it would make sense to just go with it.
BUT he is piecing together his own and the chances of someone having done extensive comparitive cam testing with his exact combo is slim. The chances of an overseas sales assistant/cam helpline employee providing added value for Brett are even slimmer. This is where dealing directly with a local expert who can hopefully look at his heads and pipes etc will provide value.
Out of interest my USA LS1 has an aussie cam while the Aussie plastic uses a crane. I am happy with them and glad I took the advice of the experts involved.

[LXCHEV]

Ok, had my heads flowed. Numbers were actually down on what we were expecting. (I have a copy of the original Pro Topline catalogue and whilst the exhaust figures were fairly accurate, the intake figures were down as much as 25cfm at high lift). Having said that, the figures are still good, and still climbing right up to .700 lift. Here's the data:

.200 .300 .400 .500 .600 .700
IN 131 178 214 233 241 246
EX 98 133 158 178 191 193

Apparently with valve seat work, and bowl work, I could gain another easy 20 - 30 cfm and really wake them up.... but for a grand I had to say no. I don't want to invest any more cash in these heads. I'd rather swap to alloy AFR's, so for now I'll just be wacking these heads back on exactly as they are.

I'm still torn on cam choice. My dyno guy (who also flowed the heads for me), has recommended this hydraulic roller:

Comp Cams Xtreme Energy XR294HR: basic specs 242/248 duration @ 0.050, 110° LSA, 576 / 600 valve lift.
(Street/strip applications, 9.5:1 compression, intake, headers, 3000+ stall, gears. Rough idle. 2800 to 6100)

Thoughts?

Also - now that I have accurate flow figures for the heads - how is the CFM related to ideal valve lift?? Are there any general rules to follow to create a magic combination?

Edited by LXCHEV, 10 September 2011 - 09:29 PM.

[LXCHEV]

Thanks Sandman, sounds like that's gonna be a very nice 400. Once it's running, make sure you report back with some results and feedback.

[LXCHEV]

Giving this old thread a bump. I had a similar thread running on another forum and was reminded recently that I never followed up on the final build combo. I'm only 4 years overdue, LOL.

 

I used to get a lot of PM's from people asking how my combo went, so for those interested, here is a final build summary of where I ended up:

 

As already mentioned, my basic component choice was:

 

4.020" 4 bolter (making 381 cubes)

SCAT crank - cast-iron 9000 'Pro-Comp' series (internally balanced)

SCAT forged 4340 'Pro-Comp' series 6" I-beam rods with ARP 7/16" cap screws

SRP forged stroker flat top pistons

Finished deck height approx 0.006"

 

 

 

 

 

Finally going together!!

 

 

Cam choice was where I got stuck when I left off last time, so I ended selecting a Comp Cams retrofit hydraulic roller straight out of the catalogue - a little bit conservative as I was concerned about not having enough dynamic comp, and also worried about too much valve lift with my 1.6 ratio rockers:

 

Comp Cams Extreme Energy XR288HR

 

http://www.compcams....x?csid=161&sb=2

 

Basic specs - duration @ 0.050: 236/242. (Advertised 288/294). Lobe separation is 110. Valve lift .555/.576.

 

 

Morel roller lifters:

 

 

I retained my original cast iron Pro Topline heads but they copped a full rebuild. They were decked down 0.080". From factory they had 72cc chambers, now they're closer to 65cc I think (from memory only). This bought my static comp back up to a much more respectable 10.4 - 10.5 or thereabouts which was a great result considering where we started off.

 

With this combo, my cylinder cranking pressure is 190 PSI on the gauge (cold engine). No idea if this is considered healthy for a hottie or still a bit low?

 

The heads were finished off with brand new 6000 series Ferrea valves, new intake valve guides, honed exhaust guides, and bee-hive valve springs to match the roller cam.

 

I kept my original RPM Air-Gap dual plane intake.

 

 

 

 

Carb choice - thought I'd try a 750 CFM Holley aluminium Ultra HP, pretty nice bit of gear with lots of cool features. I'm also running a Holley billet mechanical fuel pump:

 

 

 

More to come.....

[LXCHEV]

As far as the rest of the combo goes, I stuck with my conservative pipes (Tri-Y's) - which are 1.75" -> 2" -> 2.5" collectors, with twin 2.5" system. I did have a stainless X-pipe installed which replaced a pretty average reverse facing balance pipe, and this definitely improved the exhaust note a lot.

 

Trans is still TH-350 with 3200 stall, and I've got 3.7's down back (now with an Eaton True-trac).

I had the car on a chassis dyno to put a base tune into it, and the result was a very mild 230 rwkW (roughly around 440HP at the flywheel). I was never chasing numbers with this build, but I was a bit surprised this figure wasn't just a tiny bit higher. I think there's an awful lot in heads, and perhaps a bit more than I thought in the exhaust too. As mentioned earlier in this thread, the flow figures on my heads are down a little bit to where they should/could be, but I chose not to port, and save the cash instead.

 

Having said all that, the engine feels fantastic. It drives like an absolute baby down low, heaps of torque as expected. Great Grandma could definitely do the shopping should she wish to. But when you sink the foot in, she really wakes up, and I'd describe this combo as more aggressive than my previous combo's. Even though my old combos actually made more power. In the 4 years since the engine fired into life, I'm still yet to race it, which I'm totally ashamed of, LOL!!!

 

I reckon a nice set of alloy AFR heads would really wake this thing up and come close to 500HP. But then I start thinking of new intake (maybe even dabble with a single plane), bigger cam, bigger stall, etc.... this combo is so good, at the end of the day I've decided to simply enjoy it and stop tinkering. One day I will build my animal 10 second donk, but for now I'm happy cruising (well I don't have a choice with 3 kids now all under the age of 6!!!)  My racing days will return one day.

 

 

[Redslur]

440HP in a Torry is heaps of fun. With the right gearing would run high 11's anyway :-)

[LXCHEV]

Time for some results for those watching this topic. As per my LXCHEV thread, I finally hit the 1/4 mile with this new combo.

The result - 11.82 @ 116 MPH. Maxxis street tyres, full exhaust, 3200 stall and 3.7's. I'm really happy (was actually quite surprised). I'm convinced there's an 11.7 hiding there. Will try to hit the track again soon for another crack.

Absolutely perfect street engine, rapt with the hydraulic roller cam.