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I recently started building a 3.1 block for my stock 2.8 camaro. my original plan was to just build a stock 3.1 with a comp cams 264H cam for a low boost turbo. unfortunately, my "0 miles, well kept" purchased engine was full of sludge water, and rust.
I got the block .030 overbored and found some matching pistons and rings. lucky for me, I have access to the inventory of a retired machine shop so I got the pistons relatively cheap. In an effort to save money, I started going through the rest of the shop to see what other parts I could get cheap. I found several 60 degree long blocks that I can go through for parts.
All but one of the engines is FWD. so I looked into it and discovered the hybrid swap. I had so many of the parts needed for the swap it seemed stupid to not try it.
so now I need to decide which route to go, Build a hybrid or build a stock engine? I'll post some pictures of my available engines to take parts from. I'm not too afraid of fabrication and doing things way cheaper than I should, so as long as I can gather all the info I can to feel comfortable about the hybrid swap I'd love to attempt it. Any help or opinions are greatly appreciated!
Last edited by Heartmotorworks; 10-17-2016 at 02:18 PM.
Looking at the FWD engines you have available I'd not bother. While yes, there will be an improvement in power potential over using the iron heads, not enough to go through the hassle.
If you're going build a hybrid use the gen 3 top end, 1996+ 3400 or 2000+ 3100. These top ends will provide a substantial enough increase on power potential to be worth it.
on a separate note, is this the right bell housing? I've been having issues with the angle the slave cylinder runs into the clutch fork, and I'm thinking I accidentally put a 4th gen bell housing in.
Edit: It's the wrong clutch fork
Last edited by Heartmotorworks; 10-17-2016 at 02:20 PM.
Thanks, 6 shooter, that's super helpful. So the earlier 3100 heads are not quite as cleared up as the later and 3400? I guess my decision will come down to what pistons I'm putting in. I gave the machinist a set of gm 3.1 +.030 pistons that I found, but after researching it I discovered the fwd and rwd pistons are different. Once I get the engine back I'll see what pistons I chose to put in and I'll work around them. I would rather not buy new pistons, and if it means I have to spend extra money to do a cool swap then so be it.
I stopped by the machinist today to check out my pistons. the box says "Silv-O-lite 1486 +.75mm yatta yatta yatta 1.45 compression". If I'm not mistaken, that means I put the Aluminum head pistons together for my engine.
yay
so what exactly makes the early 3100 heads (gen II?) less of a bang than the gen III heads? and will a gen III intake bolt up to gen II heads?
I'm sure the smart thing to do would be to buy gen III heads, but if I were smart I'd just get a v8....
edit: for anyone reading this later, this is wrong. silvolite 1486 pistons are for the iron heads.
Last edited by Heartmotorworks; 10-17-2016 at 02:22 PM.
Backing up, the engines you showed are not "3100" they are gen2 3.1L. "early 3100" are gen3 but have small port intakes and heads and were first used in 1992 in SOME car lines, and all 3100 equipped car lines by 1995.
Gen2 was from 1987 to 1994. Again, in 1992 not all 3.1 equipped cars had the gen2, which makes the years of 1992 to 1994 a bit confusing when trying to discuss with 3.1L displacement 60 degree V6 is being discussed.
No, the intakes are not complatable between the different generations of 60 degree V6. Yes, you will find people that have bolted one onto the other, but the port shapes are quite different and the results have been less than optimal for those that have done it.
The reason why I say don't waste your time with the gen2 top end is because it's the EXACT SAME AMOUNT OF WORK to use the far superior (large port) gen3 top end, and the gen3 top ends are so easy to come by now, it hardly makes any sense to even think about using gen2 parts. The gen2 top end, while an improvement over the gen1 heads is no where near what the (large port) gen3 heads are, not even the same ball park. To put it another way, on a scale of 1 to 10, 1 being iron heads, 10 being large port gen3 heads, I'd say the gen2s are about a 3.5. I'd also not use the small port gen3 heads used on the early 3100 between 1992 and 1999. While again, yes an improvement over the gen2 heads, I'd put them on the scale of about a 6.5. I used a set myself WAAAAY back when large port gen3 heads were still only a few years old at the oldest, and harder to come by. I even had a large port top end, but wanted to save that for another project that never came to fruition, I should have just used the better parts from the start.
I assume you're using a RWD block for this build? If that's the case putting the aluminum heads (gen2 or 3) on will require a crank trigger to fire the DIS ignition. If this is a concern, or out of your budget stop now and get some different pistons to use the iron heads.
You will hear of people saying that you can use a dizzy with the gen2 or 3 intakes, but it's not a drop in, it requires either an offset base dizzy or an extended shaft dizzy, which for the amount of work that is, the crank trigger is a better option and IMO less work than making a custom dizzy.
Thanks, I should probably quit being lazy and check out 60degreev6 before I keep going. I researched the ignition stuff pretty heavily and that seems doable with my budget.
You're giving me a pretty heavy no to the junk I have access to, so I'll go ahead and find myself a real 3100 top end. at that point I shouldn't have too many issues, most of my issue was the sheer amount of information there is about compatibility between the v6's. I figured it would be best for somebody who's done the swap to guide me in a preferred direction.
one last stupid question: how do you face the throttle body forward for the swap? Does the upper plenum just spin to face the other direction? Thanks for the help so far!
Last edited by Heartmotorworks; 10-17-2016 at 02:23 PM.
Those pistons look like iron head ones. Here is alum headed ones. Ment for a 3400
You can clearly see how dished it is. I ran iron head pistons and I hope you relize how high that compression will be. 93 octane is a must at all times. And be careful tuning it. It'll work but you just have to be careful.
wow, am I glad you caught that. From only seeing 2.8 pistons, I had assumed all RWD pistons are flat-topped, and my "dished" pistons were FWD pistons... that'll teach me to skip checking my compression.
I pulled the head, measured everything, and found my current compression to be 12.76:1.
for anyone interested, the volume of my combustion chambers on my aluminum heads was 22cc, and I used silvolites's 12cc spec for the piston dish.
I'm not sure how thick they are, but felpro makes head spacer shims for this engine. the two head gaskets alone will put my compression at 11:1, so I'm probably looking at around 10.8:1 If I use head spacers, which I would feel much more comfortable about running with 93 octane.
Does anyone have negative thoughts about the spacers? I've never used them before.
head spacers?? I wouldnt do that at all.... Even with mls gaskets and arp studs like I have on mine. Head spacers really messes up your quench big time and when your pounding 10.5+:1 compression, you really should make sure to have good quench.
Yes the alum heads have 28cc chambers and the irons IIRC are about double that!
Rule of thumb always match the pistons to the heads. Iron heads chambers are so much larger then the baby alum heads. And if in doubt when getting pistons always look at the compression distance. You want 1.442 on a iron head gen1 and 1.478 for the alum head gen 3 i know that for a fact. The compressed gen 3 head gasket is .060 and if you run gen 3 heads then get that gasket for proper quench. The iron gen 1 head is .040 compressed same goes for that if you run the heads and pistons then get that gasket for proper quench.
Its so much easier to either toss the fwd pistons in there or run the iron heads with those pistons. I have 5 speed pro .020 over 3100 pistons id sell ya cheep already on rods. Dont ask what happend to the other 6th piston.. well ill tell ya. 15psi of boost 100hp shot off the line. It ran a 11.23@123mph and then it said im tired and shattered like glass... best pass of the year but i pushed it too far with the n20 off the line i think.
08-22-2016, 08:06 PM
