Martin, Jeff N, Others w/ cam/timing changes:

[Robin-535im]

I'm curious to hear what you think about changing cams and advancing the timing.

How's the change? Does a different cam give you more power where you want it? Can you tell a difference? Martin - have you dyno'd the 284 yet?


Questions, questions!

- Robin

[Martin in Bellevue]

Hey Robin, I haven't gotten back to the dyno yet. There does seem to be improved torque everywhere, with the 284. I returned that adjustable cam gear from Korman. It was really meant for earlier m30's & would've taken some machining to get it to fit. I am pretty happy with the straight up position on this cam. It pulls well from about 1,200 rpm, & zings to the redline noticeably harder than before.

The heresay:
Jeff's ~292 MM cam is now at about 4 degrees advance, we think. Nothing happens until 4k rpm. Not much more happens until 5,200 rpm, I'd say. Then there's a narrow band of power, and you shift into the next gear, taking the cam back out of power. Then wait some more. Watch the guy in the little Honda pull out & fly past.

Joe S has mentioned that the 2 degrees advance on his Schrick 284 moves the power down low, sacrificing some at the top of the rev band. Joe, did I hear ya right?

[JoeS]

Hey Robin, I haven't gotten back to the dyno yet. There does seem to be improved torque everywhere, with the 284. I returned that adjustable cam gear from Korman. It was really meant for earlier m30's & would've taken some machining to get it to fit. I am pretty happy with the straight up position on this cam. It pulls well from about 1,200 rpm, & zings to the redline noticeably harder than before.

The heresay:
Jeff's ~292 MM cam is now at about 4 degrees advance, we think. Nothing happens until 4k rpm. Not much more happens until 5,200 rpm, I'd say. Then there's a narrow band of power, and you shift into the next gear, taking the cam back out of power. Then wait some more. Watch the guy in the little Honda pull out & fly past.

Joe S has mentioned that the 2 degrees advance on his Schrick 284 moves the power down low, sacrificing some at the top of the rev band. Joe, did I hear ya right?

[Robin-535im]

what the cost was for that cam? IIRC, you have the IE 284 regrind, which is a stock cam reground to the same specs as the Shrick 284, right?

How hard is it to swap them, do you have to buy new head bolts or can you do it without disturbing things too much?

You and Jeff ever race head to head? There must be some empty school zones or church parking lots you could use... It's nice to have two cars to compare side by side like that, not to mention someone to make a beer run while the other car is in pieces. :)

- Robin

[Martin in Bellevue]

I pulled the head for new guides & let the machinist swap cams.

Jub Jub won't race. He'll start going on about his time of the month, when I ask to run, on the private, closed airstrip, void of traffic and cuddly forest animals.

https://secure9.nexternal.com/shared/StoreFront/default.asp?CS=ireland&BusType=BtoC&Count1=711696803&Count2=628837227

[Jeff N.]

Robin - you thinking up changing cams? Let's break it down a bit. :D

- Schrick cam, new billet we believe or welded lobes. Good reports up to a 284 with stock compression. JoeS reports that the torque curve seems to be pretty broad from about 3k RPM on. Lobe centers unknown but likely similar to stock due to torque curve. JoeS has a ported head and 3.76 rear end and a e28 (22lb) flywheel if I recall. MAF conversion.

- IE "284" cam. Grind off the stock cam. Martin has this one and it seems to run well on a non-ported head. Torque curve seems to pickup at 2.5 to 2.8k +. Lobe centers must be about the same as stock as it's a grind with no weld. Martin's running a non-ported head and 3.64 rear end with a 15 lb flywheel. MAF conversion.

- Metric Mechanic "Rally Cam" - welded lobe and ground cam to Jim R. spec. Designed mostly for his 3.7 sport motor which is overbored and with 10:1 compression. Lobe centers likely increased beyond stock as torque curve has moved higher. In a stock compression motor with 4 degrees advance, car is peaky and comes on-cam hard about 4k RPM, very noticable. Off cam performance is driveable but you miss the midrange torque of the IE 284. I'm running a ported head, 3.46 rear end and 22lb flywheel. MAF conversion. Likley not the best choice unless you plan to up the engine compression.

The Schrick and MM cams are likely about the same price. The IE 284 cam is the cheapest. I seem to recall the BavAuto engine having either a 272 or 276 cam. Stock is like 268.

Jeff

[Robin-535im]

Robin - you thinking up changing cams? Let's break it down a bit. :D

- Schrick cam, new billet we believe or welded lobes. Good reports up to a 284 with stock compression. JoeS reports that the torque curve seems to be pretty broad from about 3k RPM on. Lobe centers unknown but likely similar to stock due to torque curve. JoeS has a ported head and 3.76 rear end and a e28 (22lb) flywheel if I recall. MAF conversion.

- IE "284" cam. Grind off the stock cam. Martin has this one and it seems to run well on a non-ported head. Torque curve seems to pickup at 2.5 to 2.8k +. Lobe centers must be about the same as stock as it's a grind with no weld. Martin's running a non-ported head and 3.64 rear end with a 15 lb flywheel. MAF conversion.

- Metric Mechanic "Rally Cam" - welded lobe and ground cam to Jim R. spec. Designed mostly for his 3.7 sport motor which is overbored and with 10:1 compression. Lobe centers likely increased beyond stock as torque curve has moved higher. In a stock compression motor with 4 degrees advance, car is peaky and comes on-cam hard about 4k RPM, very noticable. Off cam performance is driveable but you miss the midrange torque of the IE 284. I'm running a ported head, 3.46 rear end and 22lb flywheel. MAF conversion. Likley not the best choice unless you plan to up the engine compression.

The Schrick and MM cams are likely about the same price. The IE 284 cam is the cheapest. I seem to recall the BavAuto engine having either a 272 or 276 cam. Stock is like 268.

Jeff