Different 3.4l piston/head compatibility (Page 7/7) 1985 Fiero GT AUG 16, 03:14 PM quote Originally posted by 82-T/A [At Work]: Hahah... I don't blame you. Besides, it would be weird having 2.8 heads on a 3.4 and 3.4 heads on a 2.8 haha, even if they are the same head. 82-T/A [At Work] AUG 16, 03:37 PM quote Originally posted by 1985 Fiero GT: Besides, it would be weird having 2.8 heads on a 3.4 and 3.4 heads on a 2.8 haha, even if they are the same head. LOL, sometimes I feel like I'm talking to a 19 year old version of myself. Except I'm sure you didn't run away from cops at the 7-Eleven after your friend puked on a cop car, nor did you watch your other friend **** on the hood of the Driver's Ed car in the school parking lot, or knock over port-o-potties at a construction site, or hack into public bulletin board systems, or skip class. 1985 Fiero GT AUG 16, 03:45 PM quote Originally posted by 82-T/A [At Work]: LOL, sometimes I feel like I'm talking to a 19 year old version of myself. Except I'm sure you didn't run away from cops at the 7-Eleven after your friend puked on a cop car, nor did you watch your other friend **** on the hood of the Driver's Ed car in the school parking lot, or knock over port-o-potties at a construction site, or hack into public bulletin board systems, or skip class. Haha yeah, more restrained but similar interests maybe haha. Learning about this 3400sfi came at a good time, I was budgeting for a parts/beater Fiero, couldn't find any good ones in the area, then I learn about this engine which will theoretically cost a similar amount to what I was wanting to spend on a parts Fiero. 1985 Fiero GT AUG 16, 08:10 PM quote Originally posted by 1985 Fiero GT: For pushrods, I read I'll need 5.85" long pushrods for the roller lifters to the Fiero heads. Does it have to be exactly that, as I can't find any right now, how much of a variance can there be, as I can get 5.75" long ones easily. I have also found 5.88" pushrods, readily available, will those work? 1985 Fiero GT AUG 16, 11:08 PM Will I need to do anything to the evap system? I'll make sure to plumb the PCV so it is boost free, but will the evap system be affected by boost? As for electronic "boost control" and a PWM IAC, all I need for those is a fast acting solenoid that rapidly turns on and off a vacuum/boost signal via a PWM input to simulate a certain constant pressure, right? If that's correct, then an EGR solenoid or evap solenoid would do the job right? Evap solenoid is normally closed, which would probably work fine for the IAC, only concern would be the amount of airflow provided, might not be as much as the factory stepper valve, boost control might be better to be normally open, so if the solenoid fails it reverts to the lower wastegate pressure, the EGR solenoids seem to have 2 different switched paths in them, normally having air running from the firewall tube (air filter) to manifold vacuum, when activated, they run EGR valve to manifold vacuum, so if I cap off EGR valve port, then it will flow from "air filter" to "manifold" when off, and switch on to block the flow, acting as a boost controller when run to the wastegate, and controlled with a PWM signal. pmbrunelle AUG 17, 12:03 AM quote Originally posted by 82-T/A [At Work]: I'd at a minimum replace the bearings and the rings. You got this... For low-budget without machining, to increase the ring gap, my suggestion is to file the existing rings, and then to put them back in the same position/orientation as before. When rings go up and down, they wear out the part of the cylinder bore where they travel. This leaves an unworn ridge at the top of the bore. If a replacement ring happens to be a hair thicker than the original ring, then it will smack into the ridge, causing something to break. If removing the ridge using a ridge reamer is a possibility, or if boring the cylinders is a possibility, then you can look into replacing the piston rings if you like. quote Originally posted by 1985 Fiero GT: pmbrunelle overbored the cylinders and installed slightly undersized pistons and rings to deal with heat from the turbo, I figure any wear on the rings/block now should be equivalent to that, but I'll keep it in mind, as I open up the engine, I'll obviously replace anything that is obviously worn/broken. My pistons and rings are off-the-shelf parts, not slightly undersized. The machinist bored the cylinders larger than normal to gain piston-to-bore clearance. I filed the piston rings larger to increase the ring end gaps. Measure parts, do not assume. Most likely the timing chain is slack. quote Originally posted by 1985 Fiero GT: For pushrods, I read I'll need 5.85" long pushrods for the roller lifters to the Fiero heads. Does it have to be exactly that, as I can't find any right now, how much of a variance can there be, as I can get 5.75" long ones easily. In general, when building an engine, you should wait to have the longblock assembled before selecting a pushrod length. Do not assume that what works for someone else will be optimal for you. For instance, La Fiera and I both use the same rocker arms, yet he uses 6.250" pushrods, and I use 6.400" pushrods. You can use adjustable "checking pushrods" to see what works for your combo. https://www.fiero.nl/forum/Forum2/HTML/141234.html With the checking pushrod, you can make it shorter/longer, and see how the variance affects the contact pattern. With vendors such as Summit Racing, pushrods are sold in 0.050" increments. There are many online articles on the topic of pushrod length and valvetrain geometry; you should do some reading on this topic. quote Originally posted by 1985 Fiero GT: Will I need to do anything to the evap system? I'll make sure to plumb the PCV so it is boost free, but will the evap system be affected by boost? Stock evap seems to work fine on my Fiero. There was a vacuum cap which blew off with boost pressure; I replaced it with a tighter-fitting cap. quote Originally posted by 1985 Fiero GT: boost control might be better to be normally open, so if the solenoid fails it reverts to the lower wastegate pressure That would be sensible. quote Originally posted by 1985 Fiero GT: the EGR solenoids seem to have 2 different switched paths in them, normally having air running from the firewall tube (air filter) to manifold vacuum, when activated, they run EGR valve to manifold vacuum, so if I cap off EGR valve port, then it will flow from "air filter" to "manifold" when off, and switch on to block the flow, acting as a boost controller when run to the wastegate, and controlled with a PWM signal. The source of air pressure used to actuate the wastegate actuator is generally high-pressure air taken just downstream of the compressor. Manifold pressure will not be as high (so less pressure can be applied to the wastegate actuator), but it could work I suppose. There are a number of wastegate actuator plumbing diagrams available online. The GM boost control solenoid and the MAC valve are two well-known choices for 3-port electronic boost solenoids. Maybe something else can work, but I guess you would have to do your homework and test. I still suggest the idea of an aftermarket wastegate actuator with replaceable springs; this way you can tune the boost pressure mechanically, without electronics/solenoids. quote Originally posted by 1985 Fiero GT: Evap solenoid is normally closed, which would probably work fine for the IAC, only concern would be the amount of airflow provided, might not be as much as the factory stepper valve Compare the size of the IAC air tube versus the size of the evap air lines, and you shall have an idea of the relative airflows... quote Originally posted by 1985 Fiero GT: this engine which will theoretically cost a similar amount to what I was wanting to spend on a parts Fiero. Normally when I triple my initial cost estimate of a project, I'm close to the actual cost. 1985 Fiero GT AUG 17, 01:13 AM quote Originally posted by pmbrunelle: My pistons and rings are off-the-shelf parts, not slightly undersized. The machinist bored the cylinders larger than normal to gain piston-to-bore clearance. I filed the piston rings larger to increase the ring end gaps. Measure parts, do not assume. Most likely the timing chain is slack. In general, when building an engine, you should wait to have the longblock assembled before selecting a pushrod length. Do not assume that what works for someone else will be optimal for you. For instance, La Fiera and I both use the same rocker arms, yet he uses 6.250" pushrods, and I use 6.400" pushrods. You can use adjustable "checking pushrods" to see what works for your combo. https://www.fiero.nl/forum/Forum2/HTML/141234.html With the checking pushrod, you can make it shorter/longer, and see how the variance affects the contact pattern. With vendors such as Summit Racing, pushrods are sold in 0.050" increments. There are many online articles on the topic of pushrod length and valvetrain geometry; you should do some reading on this topic. Stock evap seems to work fine on my Fiero. There was a vacuum cap which blew off with boost pressure; I replaced it with a tighter-fitting cap. The source of air pressure used to actuate the wastegate actuator is generally high-pressure air taken just downstream of the compressor. Manifold pressure will not be as high (so less pressure can be applied to the wastegate actuator), but it could work I suppose. There are a number of wastegate actuator plumbing diagrams available online. The GM boost control solenoid and the MAC valve are two well-known choices for 3-port electronic boost solenoids. Maybe something else can work, but I guess you would have to do your homework and test. I still suggest the idea of an aftermarket wastegate actuator with replaceable springs; this way you can tune the boost pressure mechanically, without electronics/solenoids. Compare the size of the IAC air tube versus the size of the evap air lines, and you shall have an idea of the relative airflows... Normally when I triple my initial cost estimate of a project, I'm close to the actual cost. Yes, I meant undersized pistons in comparison to the bore, sorry on the terminology, I'm definitely new to any of this information. I will research more on the pushrods, and see what I need with it eventually assembled, I got the engine disassembled today, top end looks fine, similar to my 2.8 in my Fiero now, timing chain is definitely slack though, I have already ordered a full replacement. Good to know, I'll leave my evap as is. Yes, my wording was in relation to the stock Fiero use as an EGR solenoid, as a boost controller, I would hook it up conventionally. Only reason I bring the EGR/evap solenoid up, is because it's what I have, I never get tired of working on my Fiero, so honestly if it doesn't work, I'll figure something else out, only limiting factor is money, and with winter coming, I'll have a lot of time, and nothing to do but install, tinker, and test, I'll learn through the process. I will check the tube sizes, who knows, maybe it's something that can be ported haha! Yeah I understand that, if I initially estimated this at 1500-2000, and I initially estimated a parts car at the same, both will certainly cost more, which has to be accounted for. I'm currently guesstimating $3200, engine, ECM, clutch, turbo, BOV, tubing, insulation/heat shielding, oil lines, wideband o2, all other sensors, injectors, timing cover, flywheel, bearings, all seals, timing chain/gears/tensioner, starter (3400 didn't come with one, and I'll upgrade to the lighter gear reduction one), 1985 Fiero GT AUG 28, 08:09 PM I'll have to get an idle air control valve separately, EGR/evap isn't going to do that job, although an EGR solenoid I have (I think from a blazer, 2 wire, vacuum connector, EGR connector, and a filtered pressure relief port), should work great as a boost controller, although that'll have to be figured out after the actual work is done haha, this will be a winter project, I'm not touching my Fiero until it goes away for the winter, until then I'm planning, buying, and will be rebuilding the 3400, I hope to get all the physical installation done over the winter, only leaving tuning, and perhaps the odd overseen tweak come spring. Pmbrunelle, next Tuesday I'll be driving through your area of Quebec, I'm wondering if I might be able to see the white bug in person, no problem if not, how much power do you think it's making? Any traction issues, and what tires is it running on, also I've heard mixed reports about journal bearing turbo sounds, how audible is it? pmbrunelle AUG 28, 09:17 PM quote Originally posted by 1985 Fiero GT: Pmbrunelle, next Tuesday I'll be driving through your area of Quebec, I'm wondering if I might be able to see the white bug in person, no problem if not, how much power do you think it's making? Any traction issues, and what tires is it running on, also I've heard mixed reports about journal bearing turbo sounds, how audible is it? I sent you a PM about a meeting. A week or two ago I think the car generated 227 whp (estimation) with a MAP of 200 kPa (22 deg C ambient). I have 255/40R17 Firestone Indy 500 tires on the car. 2nd gear hooks. I need to modulate the throttle in 1st to avoid excessive wheelspin, but it’s not so bad. Traction was much worse with the 215/60R14 BFGoodrich Radial T/A tires I used to have. My turbo doesn’t make bearing noises. I think it would have to be damaged to make bearing noises. I hear other turbo sounds though, whistling, and other sounds I cannot describe. 1985 Fiero GT AUG 28, 09:31 PM quote Originally posted by pmbrunelle: I sent you a PM about a meeting. A week or two ago I think the car generated 227 whp (estimation) with a MAP of 200 kPa (22 deg C ambient). I have 255/40R17 Firestone Indy 500 tires on the car. 2nd gear hooks. I need to modulate the throttle in 1st to avoid excessive wheelspin, but it’s not so bad. Traction was much worse with the 215/60R14 BFGoodrich Radial T/A tires I used to have. My turbo doesn’t make bearing noises. I think it would have to be damaged to make bearing noises. I hear other turbo sounds though, whistling, and other sounds I cannot describe. Working out the details for meetup, Good to know, I'll look into better wheels/tires for once my current BFGs are worn out, I meant that I've heard journal bearing turbos don't make as much "turbo noise" as ball bearing turbos, but I didn't know how much, not really important, but just curious if it was still audible.