Cam for my 4.1 build

[boostingbuick]

I agree. We should try to give our advice on what we have learned when we have made mistakes. Not everything will work for everyone. I think our opinion will help people who ask us for advice. I don't know it all and none us do. But we need to try to help and learn from all of this. So shake hands and move on.

 

[Ed Valvo]

Are you building a 4.1 from a NA application? There has been many who had block problems. I do not want to deter you however if the block distortion is great, you might be safer building a block with more meat in it.

 

[CTX-SLPR]

Are you building a 4.1 from a NA application? There has been many who had block problems. I do not want to deter you however if the block distortion is great, you might be safer building a block with more meat in it.

Yes we know, some of us have cracked blocks already and others don't and will deal with that if it becomes a problem in the future.

 

[Nasty]

My advice is coming from two areas. First, I stayed at a Holiday Inn Express last night :biggrin: and second I spent so much time searching and checking others combo's I feel these cars don't require big cams to make power on a street/strip car. The TB world has LOTS of cars in the 11's and a few in the 10's on a stock cam. Anything made for these engines above stock will produce more power of course and work fine for you. You have a 3k stall conv, mild heads and the 61 turbo and going with a weak block 4.1L. Any suggestion for a large cam does not make much sense. I don't care if it works, most cams will. Any turbo "street" cam for our cars will do well. Any of those cams will take you to the max limit of your current heads, turbo and short block, don't over cam. Why buy and install a cam that you can't use to its max potential? Any street cam over stock will get you through the 11's.

My OPINION, I think the 212 is overkill for you and a smaller cam should be selected. Which one? Without lots of flow data, etc you need to just generalize. The 204/214 is the smallest I would choose, a little bigger at the most 206-208 area with your current setup.

Good luck with your final choice

 

[Turbo1dr]

I've had a 218-218 cam before and it ran great. The turbo spooled up fast and it had a little lump in it at idle.

 

[Black Power]

Yeah it's a n/a block, but my dad had the parts for it and I got a set of pistons for free so I am gonna give it a shot. Went ahead and split the difference of the 208 and 218 cams and went with the 212/212 on a 112 cam. If it runs good I will be happy, if not then yeah I am gonna spray the **** out of it

I appreciate the comments and effort you guys have put into your posts. What a cool board :wink:

I'll let you guys know how it turns out.

Will

 

[Rosewood T-Type]

Dont mean to burst your bubble but if you use those hyper u break it pistons youll be rebuilding it long before you break the block.

Now let me offer my opinion on cam selection. A 4.1l has the same (aprox) size pistons as a small block chevy you will need more duration to fill the cylinders.
It sounds to me like your still going to pound on it on the street more than you going to daily drive it so I would go 214/224 or even 224/224 since its a 4.1l.
JMO
Doug

 

[Black Power]

Yeah I know I am playing with fire with the weaker block and the hyper pistons, but that's all I got...I hurt my 109 at the track a couple weeks ago, so it'll have to do. 800 bucks for a set of custom forged slugs is not gonna fly with the wife

 

[49-blues]

TRW forged pistons are like $250-$300.,the 212/212 will act like a 206/206 on a 3.8 block-i would go atleast 218/218-same im doing ,on my 4.1 stage2 im going 224/224.

 

[CTX-SLPR]

Where can you get TRW pistons for the 4.1L for that price? Are you using SBC pistons and having the rods sized for the 0.927in SBC pin?

 

[49-blues]

My Bad. I was thinking 3.8s on the pistons. I bought a set of stage2 pistons on ebay for my 4.1 build up-actually a set of diamonds and a set of ross's. Both sets were under $200. each.

 

[RobV6]

Respect any one who admits they made an error.I'm sure you didn't take on the job of be all to end all with ideas and words...Keep your ideas comin' in. we are all humans....Suject to error.

 

[TexasT]

Are you building a 4.1 from a NA application? There has been many who had block problems. I do not want to deter you however if the block distortion is great, you might be safer building a block with more meat in it.

Not wishing to take this way off but what application offerred a 4.1 in anything but NA? As far as I know all turbos were 3.8L in a Buick. TIA

Rich

 

[CTX-SLPR]

Stage blocks is what he is reffering to. The only 4.1L boosted motor from the factory were in the pair of turbo Riviera convertable pace cars in 1984 I think and they were hand built and probably stage block based.

 

[Shaun Tiede]

With an effecient turbo, you might like a reverse pattern cam even better.

Of course in a case of the factory turbo, it likes single pattern cams on a 108-110LSA. Effecient turbos like reverse pattern cams and usually 112-114LSA's.

It all depends on the turbo.

Would you consider an adjustable valve train so you can use a cam with a REAL ramp and Lie to the engine?

 

["More Boost"]

wont solid lift cams play havoc with knock sensors? how do u guys deal with this? please

 

[Shaun Tiede]

If you have a cam with a .026 lash setting spec and you run it there, then yes it will sound like a sewing machine. If you set it at a snug .020(Hot) or .015 cold if you have alum heads(which will be .020 hot), the valve train will be just as quiet as any Hydraulic. This is how I set anything on the street. It is very reliable, quiet, and runs for at least a year in a daily driver on one valve lash setting(as long as the rocker arms are locked down good and tight with good parts, even on stud mounted rockers with good studs and poly locks.)

In a case of Shaft Rockers(which are a much better way to do it than stud rockers), about the only time there are big problems is when someone was not checking things and paying attention during assembly, or they simply have inferior components.

Solid Lifter cams be them Flat Tappet or Roller, can deviate from the lash spec by .008-.010 over or under. In the case of a tight lash spec of say .015, you have more like .005 or less to play with.

In the case of Solid Roller Cams and the stiff springs/higher inertia loads, I have all but eliminated any high rpm endurance related issues by stepping up the pushrod stiffness with either more wall thickness, fatter rods, or both. Power is up, and the valve jobs look MUCH better at the end of a race season, too.

I know much of what I have said here has been unrelated to More Boost's question. However, I wish to help anyone out. If I can also help to shed some light on the underlying and hidden causes of problems which result in continual feeding of myths about Solid Lifter cams, then I am all for it.

I can't think of a single customer who after following my suggestions on proper component selection, set up, and break-in has ever looked back in hind sight regretting it. Most had never used anything other than a Hydraulic cam previously. It is so cool to hear them freak out about how much more alive their car or boat is. It is even cooler when at a car show, I hear some inqusitive individual asking them how often they have to adjust valves. To the individual's shocking dismay, I'll hear a client say with great enthusiasim and confidence "oh, hardly ever. I think in the last 2 years, I've had to set them twice. I initially checked them 4-5 times in the first week because I didn't believe it either. Then I quit messing with it because I know better now."

I have been known to tell people upfront that I will give them a full refund if after doing it my way, and they find that they're not satisfied. It is hard for some to pass on an offer like that.

In my opinion(based on lots of experience with this sort of stuff all over the world), I feel that anyone who is planning to set up their valvetrain and run a Solid Roller is asking for problems with any pushrod having less than .125 wall thickness. Especially if it is a 5/16 dia. pushrod. For crazy stuff, you'll be doing yourself a BIG favor investing in fat pushrods with thick walls.

 

[turbojack]

cam for a 4.1L

I used the CC 212/212 on a 112 lsa,,Its too big for my liking (I do a lot of street driving). It comes on real good hi up in the RPM,kind of kills the low end too much,,if I had it to do again ,I`d go with the 206/206 or 204/214 edelbrock. Maybe down the road I`ll change it out to a 206/206 that I happen to have just laying around,I`m sure it`ll help my low end (street driving)---just my two cents here

 

[Shaun Tiede]

That makes sense that the 212/212-H12 killed the bottom end. With an effecient turbo, the LSA is fine with the 112. However, an effecient turbo also likes a reverse pattern cam. The bigger exhaust cam is the culprit here.
It also play's a huge role in lag times. Not to mention that they blow out the charge earlier which makes it cold.

Bigger exhaust cams have a much greater negative impact on low end power, idle vaccume/quality than bigger intake cams do. If you were to settle on a 212@.050 intake lobe, you'd be happier all the way around with 204 on the exhaust.

The more effecient the turbo is, the less exhaust scavenge help from the cam the engine will need during valve overlap. You have to take valve overlap out because a really effecient turbo can seriously over scavenge the system during valve overlap from the high boost pressure in the intake port blowing a big charge right through the combustion chamber and out the exhaust. Hence less exhaust cam, and wider Lobe Seperation Angles.

A killer Hydraulic street cam: Our 272/262 with 217/207@.050. 112LSA for an effecient turbo, and 108LSA for a stock turbo. A great cam for a pure stock is a 262/207/108LSA. I've seen mid-high 11's out of true grocery getters on pump gas and street tires with these cams.

 

[Turbo1dr]

The more effecient the turbo is, the less exhaust scavenge help from the cam the engine will need during valve overlap. You have to take valve overlap out because a really effecient turbo can seriously over scavenge the system during valve overlap from the high boost pressure in the intake port blowing a big charge right through the combustion chamber and out the exhaust. Hence less exhaust cam, and wider Lobe Seperation Angles.

Can you explain how the turbo can blow air past the exhaust valve when the valves overlap? The intake pressure is always less than exhaust manifold pressure. So it seems to me that the exhaust pressure will actually come back in the chamber if the valves overlap each other. That's the way I see it happening. Is there anytime that the exhaust pressure is less than intake pressure.....like during spool-up?