I just picked up a 3.1 out of a 92 rs. Plans for it are this. .30 over on piston amd rings. Moly rings. Going to shave heads along with port polish intake and exhast side. Going to go with a 260 cam and roller rockers probably the 52. Also want to port and polish and gasket match the intake from trottle body down to heads. May try to find a ported trottle body and open up the upper intake with the mod. I. Already have a cold air intake on it. I also plan on haveing the block decked. My biggest concern would be the fuel sytem with me doing all that should i get the 3.4 injectors or just stay with oem from the 3.1. Dont plan onbgoing turbo or anything and not looking for a 220 plus horsepowerbmotor. Maily doing it to look stock but still have more power then stock. Im doing this build slowly over a year plus. Also what gasket set should i get since i want to keep the 2.8 intake but will have the 3.1. Should i get a 3.1 set or 2.8. And just out of curiosity what would the displacment be on it and the power and tourqe be. Thanks all. Also what other possible performancr mods could i do while im in the motor.
When you say "92 rs", are you talking about a Camaro? Is it an iron head engine? If it comes from a Camaro, then you'll need to drill holes for the starter bolts.
Yes it is an iron head and yes its from a camaro. It was dirt cheap and still a runner thats why i picked it up. And already knew about the starter holes. Probly get a kit for that
My last 3.4 with the 260 cam and a light port and polish on stock compression made 149.8 rwhp and 201 ft*lbs. Looks like you are doing more work than I did so you should be able to make up for the lack of displacement...
All the 3.1 will give you is a bit more (welcome) lower mid range torque. The 260 cam isn't really worth doing. Better to attend to some of the top end flow issues and then go for a 272.
The stock 3.1 injectors will be fine - you aren't doing anything that will use that much more fuel and the injectors have quite a wide range.
I agree with Bill. The H260 camshaft is only one step up from a "grocery getter" camshaft. If you're replacing the camshaft, the H272 will give you more bang for your buck.
Any of the aluminum head engines will kick butt on even a modified iron head engine, but it won't look stock. Do some research on the blocks, they are dead cheap and you can probably find an isuzu or van block with the starter on the proper side for next to nothing. You will be money ahead if you can find a 3.1 block from a van or Isuzu whith the starter on the proper side that does not need a re-bore. Larry
Well ive already picked up a complete running 3.1 iron head for 150$. Figured if i put about 700 into it ill have a good running stock looking motor. Again not looking for a high horsepower motor since i ride my kids in it and use it for shows. So going with a 272 cam i may do that with what ive already listed and the 3100-3400 heads ive read that u couldnt use the stock intake. I could be wrong on that. Someone correct me if im wrong
Well ive already picked up a complete running 3.1 iron head for 150$. Figured if i put about 700 into it ill have a good running stock looking motor. Again not looking for a high horsepower motor since i ride my kids in it and use it for shows. So going with a 272 cam i may do that with what ive already listed and the 3100-3400 heads ive read that u couldnt use the stock intake. I could be wrong on that. Someone correct me if im wrong
You're not wrong. Some people just don't bother reading what an original poster will post and want to ram their engine of choice down your throat.
My next concern would be clearance if i went with the 272 cam since im going to be shaving the heads and decking the block. Also i know i would have to go with a higher performance valve spring with a larger cam would i have to have the spring seats cut to fit the springs to keep it from binding
My Ferrari kit had a 3.1 from a Cavalier z24. It was built by a friend at a Nascar engine shop for a team. It was also turbocharged. It was very fast. I wont get into any numbers because it always causes a bunch of BS from backyard 'experts'. To get that does take money, If I remember I had about $5K in the engine. Your not going to get that from just a stock rebuild on a $150 engine though. I sold the car years ago, but took that engine out for another friend who wanted to use it in his road race car, and put in a stock 2.8. Hes still racing that engine.
Not trying to cram any engine choice, just pointing out that you can choose the right block to pull and have an iron head engine with the starter on the proper side. Also, the stock iron heads fit a 3100 block and you then have the option of running a roller cam in it. You would have to run the iron head pistons. Larry
The stock heads support .510" of lift on flat-top pistons. You'll have to do your math from there. Don't forget to upgrade your springs as the stock ones may bind over .460" lift, IIRC... "double"-springs are available from CompCams or Crane that support somewhere between .490" and .510"... You could also have the seats machined to accept common V8 springs that support more lift...
I'd have looked for a 3.4 as the initial cost of the core engine is by far the smallest part of the total outlay, or gone for a 3400 as suggested by others, but the 3.1 isn't a bad way to go.
Are you sure you want to shave the heads - that screws up your valve geometry unless you use different length pushrods. Ditto the block, and you'd have to also shave the intake manifold so that the holes lined up again. Far better to buy a set of high compression pistons, though it does cost more.
I use the 272 cam in a 3.4 with no clearance issues. I'd advise you to buy cam and springs etc. from the same manufacturer - don't mix and match.
As for injectors, IIRC the 2.8 uses 15 lb. and the 3.4 uses 19 lb. Early 3.1 used 15 and later used 17 (after 1990 or so). If you are worried about it and can find reasonably priced 17 lb injectors, by all means use them - it shouldn't cause you any problems.
To answer more of your questions: the 2.8 gasket is the same as the 3.1 gasket since only the engine stroke and piston heights have changed, not the bore.
Do use Fiero valves since the 3.1 came with non-HO valves (1.6"/1.3") - I believe which makes for 8.5:1 compression where as the Fiero came with HO valves (1.72"/1.42") stock making for 8.9:1 compression.
Anyone know the install height on 2.8 iron head valves? I have a low milage set of beehive springs from a 3100 which has an install height of 1.7 inches. Also have a set of tophat type valve seals (seals with a built in seat) for the same engine, they fit on about a .500 guide. Yours free if you pay the shipping. I think the 3100 springs support more lift because of their design. Larry
Thanks all for your replies. Looking at the info you all have given me and after talking to a few people about it i may change direction a little. Im thinking of going with 2.8 heads for the larger valves on the 3.1 block after i get it cut .30 over. Then instead of shaving heads i may do i higher compression piston with a 260 or 272 cam and 152 rockers. Along with porting anf polishing the whole thing.
Everything I see says your 92 3.1 has the large valve heads (HO) so you may find it's heads to be in better shape than the older 2.8 heads, but then don't believe every thing you are told here, measure the valves and see what you really have. Larry
[This message has been edited by trotterlg (edited 03-15-2014).]
sounds like a good plan!
