Damon

Well, it's winter and that means it's time to tear down the 'ol 383 and build it up for a few more ponies come the spring. Many of you know my old combo- your typical 383 stroker, 5.7" rods with KB Hypereutectic dished pistons, 72cc Dart Iron Eagle heads and a Weiand 142 roots blower with my venerable QJet on top. Cam was a blower-unfriendly single pattern cam designed for a naturally aspirated setup (272/272*, 216/216*, .455/.455" on a 112* LSA installed 1* advanced). Despite the slight cam mismatch it made great power. Pulling away from bolt-on LS-1s was absolutely no problem even with a stock converter, auto trans and highway rear gears.

It was always on the edge as far as detonation was concerned being at 9.25:1 with iron heads and a short duration cam. Had to keep the timing pretty conservative. Boost was about 5-6 PSI.

The new plan calls for basically a head and cam upgrade along with a re-bore of the block with fresh rings and bearings. Replacing the old cast iron heads I'm putting on a set of aluminum AFR 190s with 74cc chambers. The slightly lower compression (little under 9:1) and aluminum construction should keep me on the safe side as far as detonation goes, while allowing more aggressive ignition timing. And I'm still going to be running KB hypereutectic d-dished pistons, so you can understand why I don't want to get anywhere near the ragged edge of detonation. Also, KB hypereutectics require some pretty massive top ring gaps. Their construction and design puts a lot of heat into the top ring so they call for ring gaps that would normally make you fall out of your chair- .032" for a mild street blower application. Even for a n/a motor they call for a rather large .026" top ring gap. Just thought I'd mention it since they go to great lengths in their installations manual to tell you about this and why it's important. Of course the old rule always applies: when all else fails, read directions.

The cam is kind of a unique choice- I found out that Comp Cams offers a few select grinds of their Xterme Energy cams ground on a wider 114* LSA for TPI motors- right off the shelf- no custom grinding. This wider LSA combined with the XE line's dual-pattern specs with more exhaust duration and lift will make it a great blower cam, in my opinion. I'm going for the XE 268-14. It specs out at 268/280*, 224/230*, .479/.480" on a 114* LSA. Little hotter than my old cam and much better suited to a blower, but still OK to work with the stock converter. Giving a way a little bottom end torque is not a problem- I have way too much of it to stand any chance at launching the car off the line with the current combo. I'll be degreeing this cam in, of course. I like to get ll the power I'm paying for

Tearing down the 2 year old short block this afternoon revealed nothing to write home about except that the top half of the front main bearing was just about down into the copper. The blower belt tension apparently puts quite a bit of strain on the front main bearing. Not sure what to do about that if anything can be done at all. The blower belt tension is set by a spring-loaded pulley so it's not like I overtightened it. The crank itself is just fine (just a cheap cast 383 stroker crank available anywhere). Well, beat on 'em long engough and stuff is bound to wear out, I guess.

Oh, and one other thing- The oil pump pickup fell off the oil pump and was laying in the pan! Oops! That one hasn't bitten me in a long time. I was in a hurry when I built this last motor and didn't have the time to get the pickup spot welded to the pump. 9 times out of 10 it'll be fine and won't ever come off. This was the tenth time. ALWAYS weld the pickup to the pump!!! Build enough motors and this WILL happen to you! Motor always held good oil pressure, even with the missing pickup.

New horespower goal: Roughly 500 crankshaft horespower. I think that's a bit optimistic, personally, but with the better heads and hotter cam, who knows? Maybe. I figure the old combo made roughly 430-440 HP. Never had it to the track with the old combo but all inidcations from street races and my own back road 1/4 mile timed runs tells me it would go a legit low 12 @ ~115 on street radials with zero traction. Could I dip the new combo down to a legit 11.99? WHo knows? That's awful hard to do when it takes you 2.2 seconds jsut to cover the first 60 feet. As soon as the track opens in the spring I'll be ready to try, though!

Should have the new combo running in about 3-4 weeks. I'll post back with seat-of-the-pants impressions as soon as I get it running.

mefreema

Let us know how that cam works our for ya. I have the Comp Cam XE268 now too for my N/A setup with the occational nitrous but I would be very interested to hear how it handles boost since I may go that route later. Of course you have a 383 and I have a 355 so I guess were not comparing apples to apples here. That might just be my perfect excuse to stroke my motor too!

Kingtal0n

<b>224/230* </b> if you had a 350 i would say thats a bit too much cam for the small blower, but you have a 383 so... maybe it will work out eh?

I know you know my 234/244 is WAY too much for my blower. although even running lean under boost i still didnt detonate... know why? I WASNT MAKING ANY CYLINDER PRESSURE!!! lol... that cam was so funny.

the XE-262 for MARINE engines is the same as the XE262 for normal engines... except the marine cam has a 114 LSA and a BIT less @ .050. weird huh? its the cam I went with for now.

Im installing a XE262 in my OTHER car (non blown... yet) and I will see how it does with a blower soon. the low overlap design shouldnt be a problem even with the 110 LSA... it will help because im 9:1 compression and planning on 10 PSI of boost (15:1 dynamic?) so its important to have a lil overlap.

Damon It sounds like you have it all figured out, and Im definetelly open for trading thoughts and wisdom, we both have nearly identical setups going.

Damon

Talon- yeah, I've been pouring over the Comp Cams specs for weeks. I know the XE line backwards and forwards by heart now! I looked at the Marine XEs but they were all 112* LSA (the off-roads are 111* and the street performance ones are 110*), as I recall. I just stumbled over these TPI cams. They were listed as "87-up" which I took to mean replacement roller cams. Not the case upon closer inspection.

I thought the 268 XE might be a bit much but really it has LESS intake duration than my old 272 Crane cam- 4* less. But the XE has those wicked fast opening and closing ramps which net out 8* MORE .050 duration. I went back and forth on that for hours before I made up my mind. I think it'll still build good cylinder pressure. We'll see soon. Block went to the shop to be bored out this morning.

Of course, if it doesn't work out that just means I'll have that much more "safety cushion" to put a plate nitrous system on top of the blower, too. Heh heh. Oh yes, it WILL be mine!

As a side note- I'm also having them hone out my rods for full floating wrist pins. I'm not doing it for the usual reasons of better lubrication, less friction, etc- I just want to be able to change pistons without taking them to a shop to press the wirst pins in/out!

Kingtal0n

damon your right its a 112 LSA not 114 oops i keep forgetting...

and on your journal bearing note...
so your blower beat your main bearing up huh? what kinda bearing? what ratio was your blower running at?

now IM worried. Im using clevite 77's (extra thick and juicy) i was hoping it would put a stop to the problem, the whole beating the bearings deal wasnt SUPPOSED to be an issue, these blowers being good for 100K+ Daily drivers...

i wonder if the balancer plays a role? I have mine on a fluidamper. what kinda balancer you running?

Damon

Yeah, good old Clevite 77s in mine, too. I don't think it was a balancer issue, since the whole bearing wasn't worn- ONLY the top half of the bearing was starting to show copper (the half in the block, not in the cap). That would be the one that the belt tension would cause to wear, trying to lever upwards on the crank snout. I'm running 2.10:1 pulley ratio (6" lower, 2.85" upper).

One of the things I'm thinking about is to run a larger top AND bottom pulley, keeping the ratio about the same. This will cause less tension to be put on the belt (less torque required to turn the pulleys). Of course, the belt will be moving a lot faster, but it won't be carrying as much torque, which will help unload the front main bearing some.

BUT DON'T FORGET......

I dropped the oil pump pickup off the oil pump and that meant that on a moderately hard stop oil pressure would go to Zero for a few seconds before the pump would re-prime and then pressure came back. I never heard any engine noise from the motor when this happened, but who knows? You know, low oil pressure, front main is the furthest from the oil pump and the last to get oil pressure....... ??????? Coulda been a contributing factor.

At least that's what I keep telling myself. Also, this motor had 2 years of thrashing on it, one of those being with the blower. And trying to keep my foot out of the throttle once the blower was installed was damned near impossible. It got beat on some.

Kingtal0n

Well you know that blower pulleys tend to reduce harmonic whatevers you call ems...

im worried about my car now
I think a lifter collapsed...

Kingtal0n

say damon, maybe you can tell me why people would pay $2100 for a 144 holley setup rather than $1519 for a weiand 142 setup...

and worst of all I know holley owns weiand so they are probably the same thing!

i cant figure it out. can you?

Damon

Um...... well...... you see........

No.

I can't.

Since Holley owns Weiand you think they're just trying to run out of the old inventory and then jsut sell the Holley version, maybe? I've always used the Weiand.

Dewey316

i actualy don't think they are EXACTLY same thing the holley sits almost an 1" lower, but that 1" and 2ci more displancement isn't worth 800 bones in my mind

Kingtal0n

how can the holley sit 1" lower?

to me that doesnt make sense. that would make the rotors smaller, which would make the blower less Cubic inches.

i think your wrong, unless im missing somthing.

Dewey316

i am just telling you what holley told me, i also have the 03 catalog in my bathroom and it specificly says that the holley 144 universal (not the truck specific) sits aproximitly 7/8" lower than the wieand.

Kingtal0n

holley universal....

im glad you mentioned that....

Weiand 142 blower:
From intake to Top of back of blower (highest point on blower)
8 15/16" tall
weiand 177 blower:
From intake to Top of back of blower (highest point on blower)
10 15/16" tall (2" higher than the 144 weiand)


And.. Holley blower:

It doesnt say LOL. Imma email them, thats very interesting that one would be lower.

Dewey316

i will get my catolog out when i get home, but the footnote for the universall long nose holley 144 "low profile" , my catolog actualy says the words low profile, reads along the lines of "sits 7/8" lower than part #1510-00 or whatever the part # for the weiand 142 long nose.

Damon

I'd pay real money to gain another 7/8" clearance! My 2.5" cowl hood is about as "wild" as I can get and keep any kind of "sleeper" presence. And that's with a REALLY low profile air cleaner.

Dewey316

you have the 142 under a 2 1/2" cowl?

Kingtal0n

yes and I have the 144 under a 2.5" cowl too!

Damon

2.5" cowl hood on mine, too. But it's a 78 Malibu which has a bit more hood clearance to begin with than a 3rd gen.

ME Leigh

Have you ever thought of using a Comp blower cam like the 268AH-14 it has 268/ 276; 222/226 and 114 sep.

I thought that they carried an extreme power-adder cam but i couldn't find it in the cat.

Kingtal0n

that cams not bad. im sure it would make tons of cylinder pressure at low rpms... problem is when theres no boost the car may not exactly be fun to drive.

I tried a cam almost identical to that. 224/234 @ .050, 114 LSA.
It idled perfectly smooth, sounded stock, and made absolutelly NO power without the blower.

and there was another problem. it made so much cylinder pressure that with my 9:1 i was having detonation problems with any more than 5 PSI of boost. by running a 110 LSA, i improve my throttle response, drivability, more power with boost, and on top of all that, i bleed some of that nasty boost off during overlap so it becomes benficial to run more boost. i can run 9 PSI now, as oppsed to 5.

Kingtal0n

Damon, I just realized you have a 383 and your not using a .9" base circle cam?

Im in the process of building a 383 with a blower, I havnt ordered the cam yet, I was going to special order a .9" base circle cam grind...


how come you can use off the shelf grinds?

Damon

Talon- Ancient Chineese secret, my friend! I run stock rods with stock replacement ARP rod bolts and then I grind down the rod and the bolt head slightly to gain cam clearance.

M.E.- That cam was the other one I was considering for this application. It's SOOOO close to the XE268-14, jsut a little shy on lift and a smidge less exhaust duration. I coulda flipped a coin to decide it was so close in my mind. The XE was in stock, the AH-14 wasn't. Decision was simple then.

B4Ctom1

if you ever have concerns for the pistons and detonation, having a cam in the 110 range instead of the 112-114 can bleed off some cyl pressure to keep knock under control. some people will cry that you will lose some power, but if they had some dyno experience (I do) they would see that even if you want to blow a high compression car like say 10.25:1 or whether they are running low compression like yours, the power loss is minimized by the fact that there is a trade for more power through scavenging. for the widest selection of 110 cams see the comp cams catalog, I used to be a total believer in the 112-114 rule until my eyes were opened, the dyno dont lie.

Damon

Tom, I don't disagree. I'm in the fortunate position that I am not trying to use the cam as a "crutch" for too much compression. I've got this one built like an efficient blower motor shoud be. I want cylinder pressure out the wazoo but only because of the blower boost. Hence, the low compression but wide 114* LSA cam.

I'm not really a "blower" kinda guy and it's definitely not my strong suit. We'll see how this combo does real-world in a coupla weeks. If it's a dog I'll say so.

B4Ctom1

I wasnt suggesting that you need a crutch or that a guy who decides to run one would be using it as a crutch. It can be used as a crutch (like for compression, hyperuetectic pistons, small engine big blower) but even if you do not need a crutch consider running one to see what it does for you. I can guarantee you Mike Morans quad turbo beast uses no such cam or Pat Musi's nitrous breathing beast. I actually hate the unofficial 112-114 rule. I think it is better suited to lower compression street performance normally asperated. there is a great body of evidence to support using cams with no bleed for power I understand this. But the Big boys, the big name Buick turbo guys, and Turbo Import guys are catching on to the stuff I am talking about I am merely relaying it as I am seeing it.

ATOMonkey

I would suggest that you replace your oil pump with a high volume/pressure aftermarket pump. It will help with your bearing wear, plus they have bolt on pickups, so you won't need to get it welded.

You may now continue the never ending cam debate.

Damon

I got the high volume oil pump in there. I usually use one on any rebuilt motor. Cheap insurance even if it costs a few more HP to drive it.

I won't debate the cam issue. I don't own a dyno. I've never put one of my own cars or engines on one. I bolt 'em in and head down to the track and see what happens.

I agree that a race motor might benefit from some very different cam profiles but I don't build race car engines. I build street engines. The more I build the more I realize that a street engine is nothing like a race engine. One of the biggest differences is the exhaust. Damned little scavenging happens through cheap headers feeding into a set of duals and Flowmasters. I'm not saying that a tighter LSA wouldn't work better regardless, but since I'm not really a "blower motor" kinda guy, I use the cams that the cam companies recommend. If I had the time and money to try out an array of cams and see which one works best, I'd do it. I'm all about cheap HP, if it's fairly certain it will work in my particual engine. It's just there are so many question marks on what would and wouldn't work in this case.

I wide LSA cam has other benefits besides power- mostly drivability and mileage things. Stuff I normally consider low priority, but not zero priority.

Kingtal0n

I now seem to have more luck with small duration / tight LCA cams. they arnt as overlapy as high duration wide Lca cams.

weird how it works out, huh?

if it makes any difference to you, Damon, Ill be using a Comp XE270 Roller Hydraulic cam in my blown 383 motor. Ill let you know how it turns out. Dont expect much for a while though, Im still waiting on the block from the machine shop. darn, but they are slow.

B4Ctom1

hey isnt that XE270 a 110 cam?

Kingtal0n

<b>I now seem to have more luck with small duration / tight LCA cams. they arnt as overlapy as high duration wide Lca cams.
</b>

Yep its a 110. small duration, tighter LCA, seems to work better out of all the cams I've tried to far

B4Ctom1

I like it, I think its a great choice, its not as bad as some of the 112-114 cams guys think they have to run. I might go with a 112-114 if I had a little SN92 paxton or powerdyne.