Upgrade engine to Euro spec: advice wanted

[SurlaCraque]

Hey all so my son and I recently bought a 1979 Spider (see Hello from Seattle in Introductions if you care) as a father / son project. The body is straight, the interior is ok, but the mechanicals need help. It runs but we are planning on pulling the engine soon and tearing it down. The odo has 19K miles but doesn't work and according to records I have hasn't since at least 2004...

So the engine looks pretty stock for a US spec 1979 - that is to say pretty anemic. The block and head numbers track with a 2 liter 1979, the intake manifold is the hated dual plane, but the carburetor has been upgraded to a legit Weber 32/36 DFEV. The exhaust manifold looks to be the stock 4-2-1. See pics below. Aside from swapping on the DFEV carb, a previous owner removed the smog pump and dead ended various rubber hoses coming off the head; I assume these had to do with various emissions control functions.

We would like to revive the engine and bring it up to at least to the performance spec it would have had in Europe. Although I guess the Spider was never sold in Europe by the late 70s? We don't have to worry about emissions tests in WA so totally fine with deleting most of that crap, looks like it's mostly been done already anyways. We want more power and responsiveness, while definitely keeping it streetable. Not interested in dramatic stage 3 mods that add ultimate power to the top end but hurt the low end torque and idle.
So here's what I'm thinking, and I have several questions embedded below. Please feel free to answer them and or comment, I'm all ears:

- swap out the horrible stock dual plane manifold for a single plane from a 1800. Various suppliers have cleaned up examples for about $160. This seems like a relatively easy, cheap, no-brainer move.

- keep the Weber DFEV. I suppose we'll probably have to re-tune it even re-jet depending on what else we're all doing. I thought about going to dual Weber IDF 40s or whatever, but the expense ($1500?) and complication are steering me away from that option. Not sure those would be necessary for street driver either.

- I think keep the stock exhaust manifold? I read somewhere that the stock 4-2-1 system on the 1979 was actually pretty decent and there's no need to go to custom headers unless you're really going for high flow and horsepower. I also don't want to make the car louder. BTW I don't see a Cat in our system.

- Swap in higher compression pistons. I understand this engine was designed to run a 9.8:1 CR and it was detuned to 8:1 for the US market. This is certainly a big job but remember this is a father / son project so let's dig in! I have seen some confusing information out there but I believe 4mm domes will get me 9.8:1 CR with the 2000 head, correct? I do want to be able to run pump gas, and I'm assuming that is possible with 9.8:1 CR. FYI around here premium gas tops out at 92 octane with up to 10% ethanol. I have seen pistons online that would get us 8.7:1 CR but if we're going to this degree of trouble may as well go all the way no?

- Cylinder head: we will either have ours machined or swap on a reman. I think my preference would be to install a head from a 2000 F.I. engine because it would be cleaner than ours because the F.I. heads don't have most of the ports for the emissions crap that we won't be running anyways so I won't have to worry about closing them off. Will the various suppliers (Vick auto etc) accept our head as a core for a F.I. head from a later year? I'm aware that folks swap on the head from a 1800 engine for a cheap 0.4 CR increase, but since we're planning on increasing the compression ratio through the piston swap we won't want that. I suppose if I was convinced that 9.8:1 was pushing it as far as CR and pump gas, I could get the 8.7:1 pistons and the 1800 head for a final CR of about 9.1:1.

- Regarding the head what to folks feel about going to larger valves, doing a bunch of porting etc? My inclination would be to save my money and stick with the stock valves, springs etc, and do limited porting, maybe a bit of matching on the intake side to the manifold. My feeling being that a bunch of head work would be of limited utility without going to dual carbs and also it would only help the top end HP which isn't really my focus. What is the max flow I can get out of the single plane manifold and the DFEV? If anyone can recommend a particular vendor for the head swap let me know.

- Bottom end: I don't think do much aside from the domed pistons for the CR bump. Keep the rods - maybe have them balanced. Maybe have the crank balanced? I hear the cranks are pretty robust. Should I plan on having the crank turned and going up a bearing size or is that not really necessary?

- Cams: maybe a pair of mild street cams. 80/40? I don't know much about cams. I'd be willing to go one step up in performance from stock it made sense with my other mods. What would folks recommend?

TIA for any comments and recommendations. I'm thinking these mods / upgrades would get me to somewhere around 115-120 HP. Of course we'll be replacing all the seals, gaskets, etc and the timing belt and I suppose the water pump, clutch and whatever else makes sense while the engine is out being torn down.

[18Fiatsandcounting]

Sounds like a fun project! My suggestion is to start with the intake/carb and making sure the ignition timing is right for your setup, and then see what that gets you. The car was originally set up to run with all that smog equipment, so now that it's removed, the fuel mixture and ignition timing may not be optimal. Specific thoughts on your questions are below.

-Bryan

- swap out the horrible stock dual plane manifold for a single plane from a 1800.

Definitely yes on this one.

- keep the Weber DFEV. I suppose we'll probably have to re-tune it even re-jet depending on what else we're all doing. I thought about going to dual Weber IDF 40s or whatever, but the expense ($1500?) and complication are steering me away from that option. Not sure those would be necessary for street driver either.

The DFEV is a good carb, so I'd start with tuning that. Dual IDFs are impressive, but a lot more work.

- I think keep the stock exhaust manifold?

Yes, the stock 4-2-1 is pretty good, so I'd stick with that for now.

- Swap in higher compression pistons.

This is something I don't have much experience with, but others on this forum do. I have heard that pre-ignition can be an issue with CRs approaching 10, so you'd have to be very careful with how you set up your fuel mixture and ignition timing.

- Cylinder head: we will either have ours machined or swap on a reman. I think my preference would be to install a head from a 2000 F.I. engine because it would be cleaner than ours because the F.I. heads don't have most of the ports for the emissions crap that we won't be running anyways so I won't have to worry about closing them off. Will the various suppliers (Vick auto etc) accept our head as a core for a F.I. head from a later year?

I don't know about core exchanges, and there is a lot of lore out there about which head is better. The air injection ports on your current head don't really hurt anything performance wise, but you would have to plug them off as you noted. If it were me, I'd plug the ports, clean up the head and a valve job, and see what that gets you. For now.

- Bottom end: I don't think do much aside from the domed pistons for the CR bump. Keep the rods - maybe have them balanced. Maybe have the crank balanced? I hear the cranks are pretty robust. Should I plan on having the crank turned and going up a bearing size or is that not really necessary?

The bottom end is pretty robust, and while it won't hurt to balance the crank (with flywheel and pressure plate), and the rods/pistons, I'm not sure this is necessary unless you're building an engine that will spend significant time over 6000 rpm.

- Cams: maybe a pair of mild street cams. 80/40? I don't know much about cams.

I don't either, but my sense is that with cams, you need a holistic look at the whole engine including compression, induction, timing, etc. In short, it's complicated, but others on this forum have experience with this.

[Nut124]

Sounds like you have done a fair amount of research already and have a pretty good plan. Bryan has some good advice.

Nice looking car! Get those cables away from the ex manifold or they will burn. Looks like the coil and pickup cable are too short. The pickup cable you can splice to make it longer. Need to find a longer coil wire.

A few misc comments. Please pardon my incoherence;

I found that performance parts for these cars are not exactly bolt-ons in terms of fit. I had to modify or adjust most.

Yes, the IDFs are cool but can be difficult and expensive to tune. Many SCCA racers, so i've read, prefer plenum webers over IDFs. I run 44IDFs but had to do a lot of fabrication, modification, $$ of jets.

The bottom end and rods should not require anything but polish and new brgs, unless there is journal damage, which is not common. I did spin balance the rotating assy incl flywheel and clutch in my build. Cost me about $150. I push mine hard to 7500.

I'd consider the aluminum flywheel from what used to be Allison's. I have it and like it. No need to worry about the cast iron FW coming thru the bell housing at 7000rpm.

I run 10.5 CR in mine w/o problems so far. 9.8 should be fine.

The head is very good as is. Factory seat are not cut as large as they could. Bigger valves do no good unless the seat is enlarged. Not much room there. Replacing the seat inserts would cost $$ and not needed until you start asking for 160HP+.

I used Neway hand cutters and cut the factory seat to max and did use the 1mm bigger valves. I recommend the Neway cutters over having someone cut the seats for you. I cut the seats at my kitchen table. After cutting the seats, I turned the valves to the seat max diameter. The Neway set will cost you about $600 but you could sell it afterwards. I also replaced and reamed the guides.

The 40/80 cam is what I have. Not too rad. Makes power to 7000 or so. I do recommend carefully checking cam timing. Before I took my old engine apart, I degreed the cams. Intake cam was 10degrees retarded but the cam gears were not off by a tooth. Unfortunately, quality adjustable cam pulleys are hard to find. The two obvious choices both have major issues.
Any more cam than the 40/80 would seem to call for more CR, header, porting etc.

Check ignition timing carefully. Set the ignition timing based on max advance at top rpm, not to exceed 38. Mine is set at 37. Full mech advance should be in by 3500-4000. This typically places idle advance w/o vacuum to around 10deg.

Fuel delivery may fall short once you push for more power. This can lead to loss of top end that can be confusing. I'd install a fuel pressure gauge on a hose so you can see it while driving, prop it on the wiper and tuck it in when not needed or remove. I'd get an electronic fuel pump and a regulator. I have tried a few different kinds.

I'm planning on installing a bigger cam this winter. I might regret it, we'll see.

I do recommend the Guy Croft book if you can find it. That is what I used. I pretty much did his Stage II 1800 build and it hit the numbers.

Good luck. I'd be happy to offer what ever advice I can.

[SurlaCraque]

Thanks for the comments Bryan and Nut124. I didn't think of the flywheel, thanks for the tip, since I'll have the engine out may as well lighten / replace it. Yeah probably balancing is overkill since I don't plan on making a high revving monster out of this thing. On the other hand, set the kid up with a Dremel and a scale we could at least equalize the weights of the rods for an exercise.

I don't know about cutting the valve seats myself, but perhaps instead of looking to buy a reman head from a vendor if I take mine to a reputable machine shop in the Seattle area I can have them do it.

Are you guys suggesting I should tune the engine as it is first? It runs a bit rough; the idle seems a bit high and I think it's running rich but since I'm only planning on keeping it running for a little while longer til we pull the engine and do all this work I wasn't going to bother. I mean I'd just have to retune it again right? With the new intake manifold and everything.

[18Fiatsandcounting]

Are you guys suggesting I should tune the engine as it is first?

Yes, definitely. Get your present engine working as best it can, and then you can better assess what performance gains you might get. Sometimes the stock engines are in such bad states of tune (or loaded down with emission control devices) that owners assume this is how the stock engines perform.

My '71 with the original engine (not rebuilt) is a ball of fun to drive, especially when I changed the intake manifold and carb and optimized the ignition timing. It's no pavement-melting monster, but it's plenty for me.

-Bryan