[Scott McDonald]

Cam Spec ?

I have purchased a 2.2l converted head. Inside the head is a solid-grind cam with the following specs:

Cam Techniques

Intk & Exhst:
lobe cntr sep = 104.2 deg
valve overlap= 28.5 crank deg

Intk:
valve opening= 14.3 BDTC
lobe centr= 104.4 ATDC
valve closure= 43 ABDC
Duration= 237.2 crank deg
Max cam lift= .30063 in-7.636mm
Net valve lift= .45094 in.-11.453mm
lobe 'area'= 25.68 in * deg

Exhst:
valve opening= 44.2 BBDC
lobe centr= 104.1 BTDC
valve closure= 14.3 ATDC
duration= 238.4 Crank deg
Max Cam lift= .29976 in-7.614mm
Net valve lift= .44965 in-11.421mm
lobe 'area'= 25.78 in * deg

What does all this mean? I'm afraid it means this is a race cam without a lot of lower rpm torque.

 

[Travis]

Scott,

The lobes don't look too wild for street use but the lobe seperation is VERY narrow. I'm also not sure why they bothered with a split profile as there is very little difference between the two lobes.

Hopefully RallyBob will pop his head up at some point and comment as I'm still in the 'learning phases' of cam design

-Travis

 

[Scott McDonald]

Thanks Travis. If I decide to use the cam, I'm hoping that it won't be to late in it's powerband.

I just get terribly confused with cam-rhetoric. Actually, when I bought the head/cam combo the seller said Bob Legere built it(the head) some time in the past. So I would love to hear his .02c worth on any of this.

I intend on just adding some higher compression 1.9l pistons/rings, and a tuned-38 dgas Weber to what I already have.

 

[petrieopel]

This is what Cam Techniques sent me for my Opel GT.


For your Opel I would recommend our F 352-8 Solid lifter cam
Valve lift int & exh .528
Advertised duration int & exh 310 deg.
Duration @ .050 int & exh 272
Lobe separation 108
Thanks Dave
Cam Techniques

 

[Travis]

Trent,

Be sure to get your head flowed if you're considering running high lift cams like this. Few people have been able to get the 1.9l head to flow well above .475" or so. If the head wasn't prepared by one of the Bobs, the deck is stacked against you

Also, if you're running Bob/Roger/Cameffects roller rockers, the lift will be more like .548"

-Travis

 

[Travis]

Scott,

What do you mean by '2.2 converted head'? If this is a 2.2l casting, don't forget that the 2.2l head has a much larger combustion chamber. This is seriously going to lower your compression ratio on 1.9l. You'd have to run through the math to determine what size dome would be required to bring the compression up to where you want it. It may turn out to be impractical as large domes can create complications in the combustion process.

-Travis

 

[Scott McDonald]

The Head

As I was told, this is a 2.0l head(as such requires a 2.0l head gasket) which: has been milled, Mr. Legere did work to improve air-flow, better springs, Ti keepers, and had 2.2l valves installed. I may be leaving something out...

 

[Travis]

Scott,

Thats great, the combustion chamber in the head is the same as a 1.9l...

-Travis

 

[GTJIM (R.I.P.)]

Combustion Chamber

With the 2.2 valve fitted the chamber has probably been opened up to allow unshrouding of the valves so the combustion chamber would be wider.

Measure the width of the combustion chamber along the central axis of the head: 93mm wide and it will go on a 1.9L bore but 95mm wide you will need a 2.0L bored motor at least.

Pictures of RallyBob's work are always appreciated so can you load some up here - pretty please!

 

[Scott McDonald]

It's at a family members shop. So as soon as I see it, I'll take some pics.

 

[Scott McDonald]

My reply

Cam Techniques replied and said it might be a bit, "peaky."

Forgive my ignorance, but what does, "peaky" mean?

 

[calvin]

I have a new (to me) cam from Cam Techniques that I am going to run hopefully as soon as next week.. It is the F-275 B2106 which is 430 lift 270 advertised Duration at 50 with 108 sep. The next up after the one Bob talks about is is the H330 which is 486 lift 236 adv. Dur at 50 with 110 sep

As far as the split cam profile a quote from the tips and tricks thread by Rally Bob

"Camshaft: I used to run straight profile cams, that is, both intake and exhaust profiles are the same. But with a 1.9 head, and especially with the 1.5 head, there's power to be had by running a split-profile, with more intake lift and duration. My favorite streetable (solid lifter) profile is a Cam Techniques grind, with their F-306 for the intake profile (.459" intake lift, 246 intake duration @ .050") and their F-290 for exhaust profile (.435" lift with 242 exhaust duration @ .050"). I have the cam ground with 108-degree lobe separation for street use. You can either have the cam ground with some advance, or you can use an adjustable cam gear to correct the cam timing. I would run 3-4 degrees of cam advance. Idle is at 1100-1200, best power is 2500-6500 rpms".

 

[Travis]

Calvin,

Yes, the advantages and reasons for a split profile cam have been discussed here in detail in the past. I even run one in my GT. However, on the cam Scott has, there is almost NO difference between the two according to the specs. Just over .001" of valve lift, Just over 1 degree duration difference @.050"(much less that Bobs usual 4-6 degrees), and very little difference in lobe area. They are so similiar that slight variations in adjusting the valve lash could make those differences moot.

I'm still quite curious...

-Travis

 

[Scott McDonald]

Ahhh...Peaky

I just got another response from Cam Techniques. They are saying it should work OK on the street; However it will have a short, quick power band, as opposed to a broader band...I just wonder, where?

 

[baz]

short and quick is top end power it will give a lumpy tickover which you may have to ajust to 1200 or 1500 rpm to keep from stalling
you may find it will be a bit of a pig to drive as you will be in high revs a lot of the time

 

[Scott McDonald]

Thank You

I think I would be more suited to a power band in the lower to mid rpm 2.5k-5k range. So it appears as my search continues. Thanks for the help guys.

BTW- Why such a split profile?

 

[GTJIM (R.I.P.)]

The head sounds good though.

Have you asked cam Tech for their recommendation for the rev range you want? They should be able to help with another grind on another cam blank.

 

[RallyBob]

This is what Cam Techniques sent me for my Opel GT.


For your Opel I would recommend our F 352-8 Solid lifter cam
Valve lift int & exh .528
Advertised duration int & exh 310 deg.
Duration @ .050 int & exh 272
Lobe separation 108
Thanks Dave
Cam Techniques

If you have big valves, you will need valve notches about .375" deep in the pistons to avoid piston/valve interference. That is a serious camshaft, I've run it before.

Bob