I have a set of small port [don't flame me for this... For $50 I got the whole package with the exception of the timing cover and damper because the guy "couldn't get the damper off without having a puller" and mine is only for a 2-4 hole damper (actually it's a steering wheel puller) but it "pulls" double duty ] 3100 heads from a 98 Malibu in my garage. I plan on doing the swap sometime during the spring when I get my taxes back (if I don't have to pay). Now, I have a few questions:

Push rods: I know from 60DegreeV6 that the gen 2 have to use 6.24 and 5.9 inch push rods for the swap, but what about gen I?

Water neck: What water neck are you swappers using, and how is it installed? Pics would help.

Throttle body: Anyone make or have a cheap 3100 manifold to 3.1 TB adaptor plate? How much? I'm not going to use the 3100 TB.

Finally, the big one: I plan on not touching the lower end of my 3.1, so I'm not going to install 3100 pistons. Let me say that again: I'm KEEPING my 3.1 pistons. According to my Dyno2000 simulator (pretty close, actually, to the real numbers reported on 60DegreeV6) and the CR calculator at 60DegreeV6, I can expect somewhere in the ballpark of 10.75:1 CR. I would like to use a shim with the 3100 head gaskets (3.1 gaskets are .040" thick, 3100 gaskets are .060" thick and I think the shim is .020" thick), and according to the CR calculators listed above, my CR should be around 10:1. Does this sound right, for one, and is shimming a bad idea, for 2? I suppose I can expect to use 91 or higher gas, right?

If anyone wants to see my Dyno2000 files for accuracy, let me know. I have 3 files, for the base 3.1, the base 3100, and for the hybrid, and the numbers seem pretty close to what is reported by 60DegreeV6.com as to CR, HP, and torque.

:edit: I forgot vacuum lines... I got everything in pieces (and more pieces than I need, ex., the body to front head engine mount dogbone assemblies), and there is no car to take pics of the emissions sticker (engine was on a crate outside a shop for somewhere in the ballpark of 2 months before I offered $50 for the whole deal and I didn't have access to a truck). How do the vacuum lines go on this thing? The one between the port behind the TB running to the PCV is easy, the rest isn't.

 

Pushrods: I don't offhand know the length of the gen 1 pushrods, but what I do know is that they can't be used, neither can the gen 3, one is too long and the other too short (gen 1 and 3 respectively I think. Bottom line, you need to get custom length pushrods, and I'm afraid I haven't bought them yet for the swap myself So I don't know the length needed yet.

Coolant neck: I don't think that's an issue, but I may be wrong, I haven't crossed that bridge yet...

Throttle body: I honestly don't know since I'm going to use a 3400 tbody, it's slightly bigger, the 3100 may or may not be bigger than a 3.1, I don't remember...

CR and head gaskets: That seems a little low, but you have a gen II 3.1, so it's probably right. As for the shim.....don't, just buy .060" gaskets, shimming a cylinder head is never a good idea, especially with higher CR, unless you can't get around it I wouldn't shim.....if you can't find gaskets that thick, Wot Tech sells them for ~$150, they're pricey but they can handle high CR, and are reusable, as well as installing dry I believe.

http://wot-tech.com/shop/all/2-8/3-1.../prod_246.html

Vacuum lines: Another one I don't know the answer to offhand, but I'm pretty sure you need a MAP/plenum FPR line or w/e its called. But try to find a list of engine sensors for each engine, should help....

Sorry I couldn't answer all of those, hopefully someone else who can will chime in....

 

Oh and as for the octane, You should be able to get by on premium if nothing else, maybe even regular, depends on the knock resistance of these engines, Idk how resistant they are myself....But if I had to guess I don't think you'll need premium for your CR....I probably will though......

 

This is for the 3.1 gen I in my Bird, which is why I specified pushrod length for the gen I 3.1. The dish size for the gen I is smaller than the gen II and III, but bigger than the stock 3.4 for some reason . According to 60DegreeV6, the dish size is 12cc versus 8cc for the 3.4, and I know that when I calculated the dish size for the 3.1 pistons for my CR calculations using the dish size mentioned in one of the links from 60*, I came up with roughly 11.5cc.

I know the coolant neck won't work in its current state... Pointed towards the upper inlet of my radiator, it will hit the belt tensioner, I think, and it can't be installed the other way (of course, I don't have A/C!)... Maybe re-drilling the holes and using an SBC thermostat housing (our 3.1 neck is too small according to FirstFirebird's pics) would work?

I plan on keeping the original TB so I don't have to fudge too much with other parts, especially the spacing between the brackets for the alternator and the throttle lever. Unless I could use the 3100's accessories, but then the upper intake would be going the wrong way (remote reservoir on the power steering pump? IDK...).

I need to get 3100 upper end gaskets anyways (the only ones I really have are the valve cover gaskets and I think there's only one), and the CR with the 3.1's .040" head gaskets is in the 11+:1 range (11.28 according to calculators). Unless I can get away with the higher CR, of course.

I don't plan on doing this swap without a working '730 engine management system due to the fact that it actually USES my knock sensor. I may get the parts together, but until I either get a different harness or rebuild the one I have, I'm stuck where I'm at.

 

Ah, my pulley isn't serpentine, so I don't have a tensioner, I don't think I'll have issues with the coolant pipe...
As for the TB, do you mean that the alternator bracket will be right up on the throttle body? if thats the case you could always relocate it to the other side since your A/C compressor is out of the picture...
If you have any pictures of this stuff mocked up I might be of more help, sounds like your setup is a bit different from mine, and i haven't mocked mine up yet (still in teardown and part buying phase)

 

If I had a spare P/S pump and bracket, along with a timing cover (I have a spare damper, A/C compressor bracket, and alternator to head bracket) I'd finish mocking it up on the spare 2.8 block I also have in my garage (that the 3100 stuff is mostly mounted to ). I haven't made it to the junkyard in a while, and I need pics of vacuum hose routing stickers among other things (a crossover pipe, for one).

Another thing with the 3.1 TB is that it won't work with the 3100's current bolt pattern. The 3100's TB bolt pattern is backwards of the 2.8/3.1, with the bolts being on opposite sides. Heck, I wouldn't mind using my spare 2.8 throttle body (don't have the plenum anymore), but I still need the adaptor plate. Unless I can somehow remake that annoying single bar that runs between the outer bolt on the alternator to the one on the tensioner and "flip it" upside down. Hmmm...

 

do not shim the headgaskets, i'd just run the stock .040 ones. You'll be able to tune away any issues that may come up. Many have done so in the past.

Pushrod length should be checked on your engine, but the numbers that you can find on the domesticcrew site for gen2 hybrids should be very close to what you'll come up with. Pay attention to what cam they say they checked it on, the base circle on aftermarket ones is different.


those small port heads will be fine, they still flow better than the irons. Your best bet is to get a large port lower and upper intake and scrap that small port one. There is an easy 50-10 HP difference in that alone.


As for the timing cover and accessories, use all your stock 3.1 stuff. You'll probably have to drill some holes in the brackets to get them to bolt to the aluminum heads though.

I'd use the TB from a 3400 and just fab up a bracket to hold the cable. Your stock TB is way too small for this setup, the whole point of the gen3 top end is to flow more air and if you use a tiny little TB on it you just wasted all your time and money.

 

Love to. Don't have the tuning stuff, though.

How do I measure pushrod length? I suppose I can clean up a couple of my old 2.8's lifters I recently found and stick them in the modeling block (which also has a cam and crank in it).


Can't afford to switch right now. I'd rather get it working with what I have first before I do anything else. Like I said, if I could have gotten my hands on the late model 3100 or 3400 stuff for the price I got this stuff for (Can you really beat $50 for all I got?), I would have.


Still will have problems with the 3100 TB and the alternator to tensioner bracket as per the suggestion below unless I flip it over or something...

I could swear the throttle plate was the same size... I'll have to hold up one of my spare TB gaskets to it and see what it looks like.

 

The .06" gaskets (or shims) will give you a terrible quench height, .04" gives you .057" quench which is acceptable. More than that and you actually increase your chances of detonation. You need a pushrod length checker to check it correctly, although I don't know of anyone that makes one quite small enough. I had to cut about .2" off mine. I've heard the pushrods from gen 2 motors like an '88 cavalier are correct with a flat tappet cam. When you start looking for gaskets make sure the lim gaskets are either metal or paper. I can't tell you how many manifold leaks I've fixed that had disentigrated plastic gaskets.

 

you are going to have to tune this regardless, it's not going to run on the stock tune.. especially since you won't be able to run your distributor.


Pushrod length checkers are basiclaly a threaded pushrod that you put in, tighten the rocker down and then adjust the pushrod so you get propper lifter preload, remove it and then order up a set. You can find more info on 60degreev6 about the process.


the small port TB is 52mm, probably the same as yours. It's still too small though. 65mm is about perfect for a 3400 and 62 works well with a 3100.

 

I was running 10.75:1 compression in my 3.1. I did have to run 93 octane all the time and did still have some spark knock. Which, I do believe is what lead to breaking the ring lands on 2 pistons. So, its do-able but you gotta be careful with it. Also, when the car is hot, you may have difficulties sometimes with it cranking.

 

I ran 10.4:1 on my 3500 V6 and had no problems running 89 octane when daily driven, i did get a little better results at WOT with 93 at the track but overall it ran great.

on the highway the SA is up around 43 degrees, Lean cruse mode has the AFR bouncing into the 16:1 afr and no spark knock or overheating issues. I ran 26 degrees at WOT, maintaining about a 12.8:1 afr.

 

Large port TB is 56mm, and personally what I think should be used, and imo there is no point in a 62mm or 65mm on stock small port or large port, unless you've had them ported so the plenum opening can make full use of the increased diameter.

Also not to hijack the thread but since were on the topic of quench and CR and gasket thickness, will .04" gaskets work with 7.5k rpm? At some point I plan to tear it all down again and get heads and manifolds ported and drop in a high rpm/high compression cam with all new valvetrain to handle it, also going to probably drop in forged pistons and better crank rods and a better crankshaft if I can find one...

 

stock rods won't take 7.5K for very long (rated for 7K from GM).. I don't think the aftermarket H beams are much better than that either.

your best bet is to design the engine to make max power lower than that, Very easy to tweak the cam specs to move the power band down to the normal range.


52mm flows 308 cfm, 56mm flows 354 cfm . The 56 is definitely a better choice.

 

1. I have 2 FWD MEMCALs in my garage that I can't get rid of, for one, one being out of the j/y 730 I picked up, and the other out of a 727 I had bought for my Grand Prix but couldn't use (no 4th gear for some reason). I thought that everyone who knew about my 91 harness swap knew this as I used the chips (ATSR and AUXW to be specific) for VATS delete and couldn't figure out why the base timing was so screwy...

2. Don't know if the junkyard has a 3400 TB (most of the cars there are 3100s), but that still leaves trouble with the same alternator bracket (the black one on the inside of the alternator that runs to the tensioner).

3. I searched 60Degree for pushrod length checking... Didn't find much of anything.

I'm still not sure how I'm going to deal with the DIS... Might have to pick up a 3.4 timing cover and balancer for the 7X CKP signal. Especially with the fact that my block isn't drilled for it, for one, and the fact that I probably don't have the 981 crank, for 2 (still not 100% sure what year my engine is but I DO know it's a 3.1 because I've had the heads off and I KNOW 2.8s didn't have dished pistons in the RWD app).

:edit: Now that I have done some research, the plan is to use the 3.4 timing cover and damper, switch to DIS, and use a 16149396 ECM (92-93 Grand Prix, 93 F-body 3.4) ECM to control the works. I'll have to somehow manage to get my hands on some tuning stuff and use a guide I downloaded from an L-body performance website to get the tuning done beginning with a base $DF bin (3400 DOHC). Unless someone can recommend a different bin.

 

bump

Still looking for input on the water neck/thermostat housing (haven't found any decent hybrid swap pics showing this yet), and the $DF related tuning (or any bin file tuning).

Anyone have a clue as to how the 3.4's CMP signal is generated? I know there is a CMP sensor in the upper part of the timing cover, but I was wondering if there is a reluctor on the cam gear or the shaft itself (seems unlikely since the shaft is the same P/N as the 2.8 HO and 3.1's). I've been thinking of going to full SFI with DIS, since I have the injector harness and all, and there is going to be massive amounts of rewiring involved anyways.

I'm still hoping that FirstFirebird will chime in here...

 

I might be wrong, but I don't believe the 3.4 has provisions for a cam sensor....As I believe there was no SFI 3.4 RWD and thus no need for a cam sensor...And its probably not worth the hassle that being the case.....

 

I'm not sure if the stock comp could run SFI either...

 

Have you looked at the upper plenum on an F-body 3.4 lately?

 

Apparently not...

 

It says SFI on the manifold actually. The 'reluctor' is on the cam itself. You can either mount the alt. lower and route the radiator hose over it or redrill a straight water kneck to work.