I just bought me a 87 IROC with a LB9 in it. The kid told me the owner before him put a cam in it, and I was wondering if that would be responsible for its road manners. It idles like a tractor at first, needs pedal to keep it running for the first minute or two if the engine is cold, has no brakes when cold, and is slow until about 2500rpm where it just takes off. Its mostly stock other than headers, so would a bad cam choice cause all this? On top of that, I can't time the car correctly because it seems the pulley was put on wrong and the timing mark is no where to be seen when I shoot a light at it.

 

oh yea! Thats exactly what happens when some idiot puts a "nice big cam" into a little 305 tuned port - it runs like dog crap!

Look into an LT1 takeout cam. That'd run like stock, but faster. And you wouldn't have that hell of a time getting it to idle, etc.

Pulley on wrong? Que?

 

The "pulley" is probably fine. Make straight,white marks around the timing line on the damper. This should cause you to "see it" when you shoot a timing light at it.

Hope this helps.

 

Also need to disconnect the EST wire before shooting it.

 

Yeah I got the wire. I can see the notch is there when the engine is off, but when timing it it's nowhere in sight, nowhere near the timing marks. I could see it plain as day when timing my 2.8, so is it impossible that the pulley was put on a few degrees off? I turned the dist till it stalled in both directions, and still no sign of it. If I had to guess, based on a nick in the pulley that I can see with the timing light, the notch is about 60 degrees to the left of the timing marks when the light shines, but I can't be sure because it's so hard to see past all those big accessories.

 

Sounds like when they put the cam in it, they also put on an aftermarket timing cover. The timing mark on the crank damper is SUPPOSED TO BE at about 12:00 at TDC, and the fixed timing tab is SUPPOSED TO BE welded to the center of the timing cover, and easily visible looking straight down the front of the motor behind the water pump. No interference from accessories AT ALL. If the tab is over by the PS pump, then forget the marks, they'll NEVER work right; and just set the timing to where it runs right and leave it alone.

Best thing to do might be to buy yourself a reasonable sensible cam; and just put the right thing in it. Some PO probably picked a cam based on wanting a "lopey idle", which is GUARANTEED to make a TPI motor sluggish and gutless. Sounds like a typical PO kind of screw-up, which you'll now just have to fix.

Get a stock timing cover while you're doing the cam thing.... virtually any late-model car or truck from about 78 or so on up, will have the right thing. Or you can buy one from GM new. I don't know of ANY aftermarket TCs that have the right timing tab. Why that is, I have no clue; all I can do is report what I observe in that area.

 

A big cam makes big power but you have to comprimise.

First off a stock distributor wont cut it, youll need it recurved.

Secondly, you can advance it enough, so it runs smooth, but it will start knocking at higher RPM if u leave it like this. Or you can have it retarded, like it now, and have the high end power, and absolutely no low end power or driveability.

Various ignition companies like MSD sell a module, that has a built in retard feature. You can also have a little **** inside the car to control it. Leave it advanced to start and idle, and put it to retard for goin fast.

 

Don't forget the rest of the thought... IN A SUITABLE MOTOR. A big cam in a little motor, and ESPECIALLY in any motor with TPI on it, and ABOVE ALL in a 305, guarantees a failure.That's PROM programming.

Basically, if the cam is inappropriate, it needs to go. There's no sense in trying to work around it. ANYTHING ELSE that one might do to get around the problem, will cost as much as or more than a new cam; and has AT BEST a low probability of accomplishing anything.

 

Yes ofcourse. I overlooked the LB9 part. But he did mention it takes off like crazy once in the power band. So maybe it wasnt selected all that terribly. However, not everyone is willing to sacrifice idle for power.

 

Best bet might be to remove the accessories and the timing cover, unbolt the timing chain sprocket from the cam, and see if there are any stampings on the business end of it.
If you can afford to have the car up on blocks for a week or so that is.
Then after you post the numbers up here, we can tell you what it is, if it's worth trying to tune around, or if you should simply toss it and get a more appropriate cam.

 

Yeah I'm no expert but this is definitely not the right cam for the engine. Sofakingdom you are right on, the tab is near the PS pump. I set the timing by ear (after wrestling with that damn egr solenoid) and it idles a tad better. I really didn't wanna have to change the cam because it's so involved, when I'm going to be swapping the motor once I build my new one. I think I can put up with it till then. So I should stay out of the higher RPMs as long as I have it timed this way?

 

You could also time it with a vacuum gauge. Set it where the vacuum is highest. Every motor is slightly different so I think this is the best way to do it. Unless you have to worry about your total timing advancing too far. But with that cam, the motor will take more timing before it detonates.

Also! I had a 305 in my car in germany, and pulled the cam and put in an lt1 with 1.6 rockers (around .470 lift I think?). I had to up my timing to almost 20 degrees base to get the highest vacuum reading. It had a lot more low end power and idled much better. This could be part of your problem.
Swapping cams in a 305, isnt worth the work I feel. Put a 350 in it man. Save yourself a lot of work later.....Just my opinion. Your car deserves to be faster!

 

Yeah batass I'm looking for a 350 to build. The plan is fast burn heads and the zz4 cam, with the stock TPI and the SD baseplate. From what I've been told this would be very streetable.

 

It would be streetable but not a good combo I dont think. The fast burn heads have large runners, 215 I think? If it is 215, they wouldnt be good on a 350 for the street. Better on a 383 or 400-406. Those heads have a rough rpm range of 2000-7000. Stock tpi is like 500-4500. If you really want to keep the stock tpi, go with a smaller head. (intake runner wise like 170-195). A great budget street motor would be a vortec head-stealth ram intake combo. zz4 cam would be ok but you could do better. Do a lot of research man, I do tons and still sometimes regret the parts I buy....

The best advice I could give you is, if your planning on building another motor, dont put much time and money into that 305. Not that I dislike 305's or anything...just not money and time well spent.

 

Fast burns have 210cc intake runners. I was afraid they'd be a little too big. I was drawn to them because they claim a more efficient combustion chamber design, and I really want to go aluminum. Does it help that the SD TPI manifold needed for these heads flows more?

Edit: If not, what about E-tec 170cc heads? It seems no one likes Edelbrock, but they look decent for what I want no?

Double edit: Actually, the 385 fast burn crate engine from GM is a ZZ4 with fast burn heads, so the cam will work. The only question is, will it work with a TPI system?

 

Fast Burns or e-Tecs are both Vortec pattern. Which means you need the $$$special$$$ Vortec TPI intake base for either of them.

A ZZ4 cam would work fine in your 305, except that you'll have to watch out for interference between retainers and the valve guides on the exhausts. DO NOT attempt to run that cam with your stock valve springs!!!

What's your REAL priority; fix the 305, or build a 350?

I don't know how serious you are about the 350 of the future at this point, but if you want to get your 305 to run right, change the cam and timing cover. You might find that you don't need a 350 quite as bad. And of course, you can re-use both the TC and the cam, in your hypothetical 350. No wasted money.

 

I'm leaving the 305, because I am definitely going to build a 350. I don't see the point in spending that much time on the 305 when I'd be half way to taking the engine out anyway, which is what I want to do. I've saved money just for this. I really just wanted initially to know if my troubles were linked to the cam, or if I should check other areas.

So my search now is for a head and cam combo to use with the stock TPI on the 350. You make a good point with the vortec base, it automatically adds 400 dollars to any heads that need it...

 

dude just get some stall!!!!

 

Well, I would do the timing, it probably wasnt set right.

I forgot they were a vortec face. You'll get a page full of answers for heads, depends on how much you have to spend......how much power do you want?

That tpi intake is really restrictive. You would see roughly the same power gain upgrading that intake and keeping l98 heads, as using better heads.
The biggest thing to make an efficient power engine is using close matching parts.
Good flowing heads, good flowing cam, crap intake=poop.
If the car will be driven a lot, go with some smallish heads and smallish cam to make good low end torque and decent mileage, if only a weekend warrior, get some 190-200 heads, a better intake and a 525+ lift cam.
Or you could build a 383 which hardly costs more and use those 210 fastburn heads, put a carb on it (cheap!) a mid 500 lift cam and make a 500hp burner!

I built a 383 with 200cc RHS lightning heads a comp cam xr288hr (roughly 570 lift with 1.6 rr) and it wasnt too pricey, and it hauls whoopy. The pricey part was the forged parts and getting the engine set up.

You have a lot of research to do my friend.

 

Yeah, I'm leaning more towards something like the E-tec 170's now. Thanks for stopping me from getting the Fast Burns, I'll wait till I have a weekend warrior to put those in.

 

Why do you like the e-tecs? They're a good head, but they are hardly better than stock vortecs. You wont see any power increase with aluminum if you dont change your compression. You can possibly even lose power because of the lost heat in the chamber compared to iron. I think you also have to use center bolt valve covers, not sure.

If I were you, and this is what I was going to do, get the RHS Pro-torker (maybe torquer?). They flow 15cfm better, outpower the e-tecs, and if you look around you can find a bare set for 500 bucks. If you get a crappy deal, they are still cheaper than e-tecs.
They accept both centerbolt and perimeter valve covers, and accept both vortec and non vortec intakes. So you could use your stock tpi.

Super chevy online did an article with them called the Twister, check it out.
Shaver engines also built a motor with them that made 534hp!

My engine builder said that for a mostly drag car that I should step up to 200cc heads. The are the exact same chamber and design. Very good quality.

 

I read a lot of bad posting about e-tecs, but when I read this, they didn't seem so bad anymore. I vaguely remember reading that issue too, it's probly around here somewhere. Honestly though, about an hour after I posted that, I changed my mind and am now looking at Trick Flows. The thing is now that I kinda liked the idea of the vortec baseplate, since it's said to flow the best and add power by itself, and Trick Flows, as I understand, bolt up to the stock base. BUT the thing with the vortec is I need to hook up an external EGR, but my headers don't have the hookup, and I can't weld. At the moment I think I may just stick with the stock base for now as I'm running out of money and it makes things easier, but who knows what I'll wanna do after another hour of searching.

 

Yea the etec are a good head. My engine builder the exact engine as mine except for those heads. He made 470hp with my cam (.520 .540 288 294 110 lsa). The The RHS heads make the same, but are cheaper, and you dont have to change your compression. The extra point you could run with the e-tecs would bump it up about 13 hp.
Trick flows are nice too, they have different angle valves, like a reverse vortec, instead of changing the runner angle. I thought about using them, they are well priced but they limit your piston selection because of the different valve relief cuts, and I couldnt use them to get my desired compression with a 6" rod.
The 210 heads picked up 30hp over the rhs vortecs. Cam was the next step down from above.
If you plan on holding on to that tpi intake for a long time, I would recommend going with a 170-180 head. That intake will really choke you above 4500 rpms, no matter what head, leaving you to rely on low and mid range power.

Your car will really be faster with a small runner head.