Originally posted by L67: if you abuse this engine, things will get very ugly very quickly.
What do you mean by that statement? It is no different than any other DOHC engine. If you don't keep oil in it then yes, things can get ugly real quick. Other than that it can be thrashed on a daily basis without anymore concern than other engines. I know because I have done so with mine for 5 yrs now on almost a daily basis. It had 60k when I installed it and it now has over 160k on it and still runs great.
Originally posted by dobey: ...beyond wishing 1st gear was more usable, I haven't seen any complaints about the other gears from anyone using the F40 trans.
Ok.
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Originally posted by Erik: What do you mean by that statement? It is no different than any other DOHC engine. If you don't keep oil in it then yes, things can get ugly real quick. Other than that it can be thrashed on a daily basis without anymore concern than other engines. I know because I have done so with mine for 5 yrs now on almost a daily basis. It had 60k when I installed it and it now has over 160k on it and still runs great.
It is no different from any older technology overhead tappet DOHC engine, prone to routine service. Weren't you also claiming 300 bhp in some other thread?
It is no different from any older technology overhead tappet DOHC engine, prone to routine service.
What prone to service are you talking about? Timing belt? The 93-99 N* has the same overhead tappet technology. So do Ferraris I have seen many 3.4 DOHC engines last 200k or more , having done timing belt service for customers who came in with 100k + one with a 150k engine that either finally shredded the belt or just needed the 60k service way late.
Also, why the snarky reference to something that isn't even relevant to your claim?
Besides that you still havent explained how things will get ugly real quick with the engine if you abuse it. Explain what you mean by abuse.
[This message has been edited by Erik (edited 08-03-2010).]
Originally posted by Erik: Besides that you still havent explained how things will get ugly real quick with the engine if you abuse it. Explain what you mean by abuse.
What prone to service are you talking about? Timing belt? The 93-99 N* has the same overhead tappet technology. So do Ferraris. I have seen many 3.4 DOHC engines last 200k or more , having done timing belt service for customers who came in with 100k + one with a 150k engine that either finally shredded the belt or just needed the 60k service way late.
I will address this one time. I think the DOHC is a very cool engine, but I personally have had the following experience with it. I don't mean to offend anyone. If you love the DOHC, don't read this, it is my subjective negative opinion.
As well as just about every older model european and domestic overhead cam engine, they're all prone to additional wear verse a roller lobe variation if not taken care of very meticulously, which includes; proper oil specification and level, religious filter changes, ZDDP additives - given the the EPA mandate to eliminate ZDDP from all non racing purpose oil, and close monitoring of engine temperatures. I have had to closely monitor all of this with my education, and it grows tiresome.
There is the definitive list of parts that separate the LQ1 from Ferrari, Audi, Ford, and the like; an intermediate shaft - four additional failure prone bearings, a chain to belt transmission to drive the four cams, and considerably larger firefly lifters and cam towers than European counterparts - also to be taken into consideration with weight. Ferrari's 3.5 Liter DOHC V8 - which I think closest resembles the LQ1 - has a 6,250 mile service interval new, which progresses to a 12,500 mile interval after the warranty expires. Erik, haven't you laid claim you used to drive an F355? If so, this isn't news to you. Belt maintenance is every 31,250 miles or three years, which ever is first. Half of the suggested interval for the LQ1, but a well worth fact knowing, being you compared the engine architecture.
The older Northstar and 4.0 Aurora engine were a nightmare. An all aluminum block not being heat cycled correctly by older conservative drivers, timeserts, head gasket failures... the list goes on. A working Northstar is glorious to drive, but once again, it must be maintained.
I have also seen a 200k mile plus LQ1, and there is little coincidence that the owner is a gear head who understands oil viscosity dynamics, thermodynamics, and the need to replace the belt at service intervals. I have also seen many... many... let me restate that, many 100,000 - 140,000 mile engines in the yard that were abused and didn't make the cut. Chances are the belt is broken, but if it's not, pull the number one front main bearing cap off and enjoy what you find. If even the ZDDP levels in the oil fall off, the flat tappet camshafts will begin to grind into perfectly round circles, and the intermediate shaft will need to be pulled out to replace the intermediate shaft bearings, which wear at a seemingly accelerated rate. If the intermediate shaft bearing pressure drops off, oil isn't delivered to the cams at a stable pressure, and you once again end up with round cam lobes. Another favorite fact of mine, is that capping the throttle body coolant passageway will cause heat fluctuations great enough to leave aluminum shavings in the oil pan.
Is the engine reliable - that depends on the owner. Would I drive across the Sahara desert in a car with a full tank of gas and an LQ1, absolutely not.
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Originally posted by Erik: Also, why the snarky reference to something that isn't even relevant to your claim?
I'm going to let this thread continue soldiering onward out of respect for Eric Jacobsen. If you truly want to know why I brought that up, pm me and I'll tell you.
[This message has been edited by L67 (edited 08-04-2010).]
Can a Turbo 3.4 dohc make 400 horsepower, yet still be a reliable daily driver at the same time? Or is that just too much horsepower added on to still be reliable..? And if that's the case would it be reliable if there was a boost controller in the car and just turned boost down for daily driving and up for racing?
Can a Turbo 3.4 dohc make 400 horsepower, yet still be a reliable daily driver at the same time? Or is that just too much horsepower added on to still be reliable..? And if that's the case would it be reliable if there was a boost controller in the car and just turned boost down for daily driving and up for racing?
You should ask Matt Hawkins ..I see no reason why it woudnt be reliable just as long as you design the turbo system correctly and engine management is correct for the app.
Originally posted by L67: I will address this one time. I think the DOHC is a very cool engine, but I personally have had the following experience with it. I don't mean to offend anyone. If you love the DOHC, don't read this, it is my subjective negative opinion.
As well as just about every older model european and domestic overhead cam engine, they're all prone to additional wear verse a roller lobe variation if not taken care of very meticulously, which includes; proper oil specification and level, religious filter changes, ZDDP additives - given the the EPA mandate to eliminate ZDDP from all non racing purpose oil, and close monitoring of engine temperatures. I have had to closely monitor all of this with my education, and it grows tiresome.
No motor will escape excessive wear if the oil is not proper for the app and it is not kept at the proper level and kept clean, that is a no brainer. Hundreds of thousands of older DOHC engines from the 90's that have no need for the protection offered by ZDDP survive past 150k even with their owners lack of proper maintenance. Yes they will wear down faster if not taken care of but they are no more prone to extra wear than the typical pushrod engine of which ZDDP is more critical factor from the 80s and previous.
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Originally posted by L67: There is the definitive list of parts that separate the LQ1 from Ferrari, Audi, Ford, and the like; an intermediate shaft - four additional failure prone bearings, a chain to belt transmission to drive the four cams, and considerably larger firefly lifters and cam towers - also to be taken into consideration with weight.
IIRC, the F430 and or the Italia use a balance shaft which means more bearings to wear. The L67 has a balance shaft as well due to its inherent unbalance of which the VINX doesn't need one and the VINX can rev to 7k all day long, every day for 5 yrs to which I can attest The SBC does fine driving a distributor and oil pump with its chain drive with no abnormal wear on the cam bearigs. Some audis have balance shafts, Porsche has them. Most I4s have them I really see no problem with the DOHC intermediate shaft and its bearings having dissasembled several in the past few yrs with high miles on them Besides that it is so nice that we have moved past the stone age technology of pushrod engines with the DOHC engines which are generally more efficient and have more power with a few exceptions
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Originally posted by L67: Ferrari's 3.5 Liter DOHC V8 - which I think closest resembles the LQ1 - has a 6,250 mile service interval new, which progresses to a 12,500 mile interval after the warranty expires. Erik, haven't you laid claim you used to drive an F355?
No I did not "lay claim" to drive a F355. I did own a 308 though and understand the required service intervals of which I performed myself. I am also the only Alfa 75, 164 mechanic that I know of in Iowa which has a Ferrari v6 engine that requires "service intervals" in the same manner.
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Originally posted by L67: If so, this isn't news to you. Belt maintenance is every 31,250 miles or three years, which ever is first. Half of the suggested interval for the LQ1, but a well worth fact knowing, being you compared the engine architecture.
I just stated that the bucket tappets are shared and overhead cams are shared. A Ferrari engine is a very expensive piece of machinery and while you could risk it and go past the required maintenence interval, it would be better to save 20k or more by spending 5k
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Originally posted by L67: The older Northstar and 4.0 Aurora engine were a nightmare. An all aluminum block not being heat cycled correctly by older conservative drivers, timeserts, head gasket failures... the list goes on. I working Northstar is glorious to drive, but once again, it must be maintained.
There are tons of early niney N* caddies still being driven by old people, young people, moms, dads just as there are tons of buicks, other W bodies from the 90's with the 3800 being driven around still . Yes some early N* suffer headgasket failure and some newer do as well through 99 and rings did stick on some older ones because from its inception the N* is a very high performance engine that the engineers and beancounters stuck into cars being driven by pretty much older sedate people at first who did not drive it like they stole it. It has been remedied with redesigned pistons and rings back in the later 90's.
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Originally posted by L67: I have also seen a 200k mile plus LQ1, and there is little coincidence that the owner is a gear head who understands oil viscosity dynamics, thermodynamics, and the need to replace the belt at service intervals. I have also seen many... many... let me restate that, many 100,000 - 140,000 mile engines in the yard that were abused and didn't make the cut. Chances are the belt is broken, but if it's not, pull the number one front main bearing cap off and enjoy what you find. If even the ZDDP levels in the oil fall off, the flat tappet camshafts will begin to grind into perfectly round circles, and the intermediate shaft will need to be pulled out to replace the intermediate shaft bearings, which wear at a seemingly accelerated rate. If the intermediate shaft bearing pressure drops off, oil isn't delivered to the cams at a stable pressure, and you once again end up with round cam lobes. Another favorite fact of mine, is that capping the throttle body coolant passageway will cause heat fluctuations great enough leave aluminum shavings in the oil pan.
I have taken apart 5 or 6 DOHC engines from 91- 97 in the past several yrs and only one had any bad main bearing ..IIRC 2 had 1 bad rod bearings but the rest had no appreciable wear on the crank mains or rod journals nor did they have severe intermediate shaft bearing wear, all with varying miles on them. NONE of them had any out of spec cam lobe wear. I have a stash of good cams now for future regrinds
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Originally posted by L67: Is the engine reliable - that depends on the owner. Would I drive across the Sahara desert in a car with a full tank of gas and an LQ1, absolutely not.
The engine is reliable just as long as you do the cambelts at 60k and change the oil at required intervals. There is no black magic to maintaining this reliable engine
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Originally posted by L67: quote Originally posted by Erik: Also, why the snarky reference to something that isn't even relevant to your claim?
I'm going to let this thread continue soldiering onward out of respect for Eric Jacobsen. If you truly want to know why I brought that up, pm me and I'll tell you.
If you cant bring it up on the thread then it really doesn't matter
One thing I will say is ..run an oil cooler if you are using conventional oil and operate under extreme heat conditions. The DOHC has a long oiling circuit and the oil could coke up over time on the walls of the passages and restrict flow to where extended period of high rpm could starve the top end of oil ...
its more common than the 9396 and basically the same. there are step by step pin outs in the build thread for converting the fiero harness to the 7730 or 7727
The '727 is a weatherproof under hood version of the '730, but both are single injector driver ecm's. The only upside I can think of would be the use of Code '59. The tables aren't set up for the dohc's kind of rpm, you're going to lose a lot of tune definition because of granularity between 4800 and 8000. The 9396 is better suited to the application, the 6401 even more so.
Are you still looking for a harness builder, or are you looking to take a stab at it yourself?
I got a 97 upper and lower manifold for my 91 engine. I have heard that I need to use the 91 fuel injectors because of their spray pattern... is this true?
Also what is the benefit of the 97 intake manifold swap on the earlier engine.
The only advantage in using the 97 upper and lower intakes is that you can take the upper intake off to get to the plugs. To get a performance gain you have to swap from the heads up. The big difference between the early and the late engines is the size of the intake and exhaust ports on the heads.
Joe Sokol
------------------ 85 SE Daily driver with a 3.4 DOHC OBD II 88 Formula/GT 4.9 Allante Intake (My Baby)
The only advantage in using the 97 upper and lower intakes is that you can take the upper intake off to get to the plugs. To get a performance gain you have to swap from the heads up. The big difference between the early and the late engines is the size of the intake and exhaust ports on the heads.
Joe Sokol
What advantage is there to taking the UIM off to get to the plugs as compared to the earlier intake of which you don't have to take the UIM off to get to the plugs?
There is a performance advantage of using a 96-97 instake manifold on the earlier engine as there is no restriction to flow as compared to the ealier intake.
Also, if you want to move the power band up eliminate the intake neck and mount the TB on the plenum. I did this and noticed more pull on the top end with no noticable loss of power on the bottom end. + it looks cleaner and frees up some space for a turbo
[This message has been edited by Erik (edited 09-22-2010).]
Rumor is that GM changed the injectors in '94-'97 to try to fix the phantom stalling problem the DOHC had. The later year injectors flow roughly the same amount, are quieter, and are supposed to prevent the stalling problem. IIRC the electrical connectors are the same also, but I'll be sure of that before I ship out your harness.
Yes the injectors are the same connector, i just want to make sure of the interchangeability... new old stock injectors for the 96-97 are dirt cheap on ebay.
Very excited about the harness, keep up the good work L67
Erik, did you have to make some kind of plate to adapt the TB to the UIM? If so, do you have a pic of it, or a diagram on how it looks? Also, where did you take your vacuum for the brake booster from after you lost the "arm". I don't use the MAP sensor location anyway so that is no big deal.
Thanks
Rob
[This message has been edited by qwikgta (edited 09-27-2010).]
Erik, did you have to make some kind of plate to adapt the TB to the UIM? If so, do you have a pic of it, or a diagram on how it looks? Also, where did you take your vacuum for the brake booster from after you lost the "arm". I don't use the MAP sensor location anyway so that is no big deal.
Thanks
Rob
Yes I made an addapter plate out of aluminum stock. I dont have a pic of it but I could take one. I am not sure if I drilled a hole or if there was already a port below the throttle body on the UIM but there is a vac port there and it works great for the brake booster. I'll try to get the dimensions of the adapter plate or, if you like I could probably make one for you.
Yes I made an addapter plate out of aluminum stock. I dont have a pic of it but I could take one. I am not sure if I drilled a hole or if there was already a port below the throttle body on the UIM but there is a vac port there and it works great for the brake booster. I'll try to get the dimensions of the adapter plate or, if you like I could probably make one for you.
Thanks. I may try to do this, or have it done. I was looking at making a smaller one (arm) about an inch or two, and have it angle down instead of toward the driverside firewall. Have a port for brake vacuum and it would make the area around the shifter linkage, fuel hose, and TB. Just to clean it up.
Thanks, maybe a close up shot from the side.
For vacuum your not talking about the PCV valve port are you?
I need a little help with a customers 3.4 dohc car. I have a customer that just bought a fiero with a 3.4 motor that the guy just installed and from what I can see so far it was done right. but the car will start and run for about 30 seconds then quit. I do not think the computer was ever retuned could this be the problem ? and if so who does the computer tune and how much? any help or ideas on this would be great. I think it is in the computer not the install but I have not had a chance to look it over that much yet. D.
I need a little help with a customers 3.4 dohc car. I have a customer that just bought a fiero with a 3.4 motor that the guy just installed and from what I can see so far it was done right. but the car will start and run for about 30 seconds then quit. I do not think the computer was ever retuned could this be the problem ? and if so who does the computer tune and how much? any help or ideas on this would be great. I think it is in the computer not the install but I have not had a chance to look it over that much yet. D.
Maybe injectors, fuel issue? Put a fuel pressure guage on the rail, and see if its getting 45-50 psi. see if it stays up while motor is on. How does it run for those 30 Seconds?
I need a little help with a customers 3.4 dohc car. I have a customer that just bought a fiero with a 3.4 motor that the guy just installed and from what I can see so far it was done right. but the car will start and run for about 30 seconds then quit. I do not think the computer was ever retuned could this be the problem ? and if so who does the computer tune and how much? any help or ideas on this would be great. I think it is in the computer not the install but I have not had a chance to look it over that much yet. D.
What ECM are you using? The 91 - 93 9396 ECM doesn't have VATS but the 94-95 ECM does. If you are running an auto tuned 9396 ECM memcal it could cause it to stall
[This message has been edited by Erik (edited 09-29-2010).]
the motor runs great for a short time then dies. we just picked up the car this weekend and I have not had a chance to look it over yet myself. I will check for fuel, spark and injector pulse once I get it to the shop. then I will know more. I am not sure what computer it has yet but I will find that out as well. I am just looking for a place to start looking. I need to clean ou the wiring a little so I will also look at that as well. once I know more I will post here again. thanks for the help, Dean
I hope to be working with Archie in a few weeks on my new LS3/6spd install. And will have a complete 3.4 DOHC motor/5 spd trans on a 88 cradle for sale. The cradle will come with a complete suspension minus the struts and sway bar. The suspension has all new poly. The motor will have the Custom Headers, Y pipe and WCF exhaust included. Combo has over 2000 miles on it, and is trouble free. NO CODES.
THIS WILL BE A COMPLETE PLUG AND PLAY. YOU DROP YOUR OLD MOTOR OUT, PUT THIS IN AND SHOULD BE DRIVING IN A WEEKEND.
The motor is a 1996 with approx 30K on it. The car is an 88 coupe, so for you 88 guys this is a no brainer. For the 84-87 guys, this is your chance to upgrade to the 88 rear end. The motor swap was done by me, and I built the harness. This swap does not have A/C hooked up, but the harness is not cut. SO anyone who wants A/C can install a compressor, and finish the harness. I am running the 9693 ECM with a 91 harness from a 5 speed car. (Still have the Getrag). I may even be able to drop it off at your house, if you live between Virginia Beach and Chicago (Archies).
You can find most of my build threads using the "Search" and "3.4 DOHC" look for posts by qwikgta
I have about $3500 into the swap, and would like to get $2000 for it. Remember, this is a true Plug and Play. you will only need to do/buy a few things that need to be done anyway.
I am posting here first, to give you all first shot at it. Some of you install these into others cars. You may want to purchase it, and have it ready to plug into someones ride. Maybe you know someone who is looking. I really think that $2K is a good price for this. BUT, if someone wants to talk about it, PM me.
Rob
.
------------------
88 Coupe, CJB T-TOP, 1996 3.4 DOHC and a GT clip
[This message has been edited by qwikgta (edited 10-06-2010).]
I hope to be working with Archie in a few weeks on my new LS3/6spd install. And will have a complete 3.4 DOHC motor/5 spd trans on a 88 cradle for sale. The cradle will come with a complete suspension minus the struts and sway bar. The suspension has all new poly. The motor will have the Headers and exhaust included. Combo has over 2000 miles on it, and is trouble free. NO CODES.
THIS WILL BE A COMPLETE PLUG AND PLAY. YOU DROP YOUR OLD MOTOR OUT, PUT THIS IN AND SHOULD BE DRIVING IN A WEEKEND.
The motor is a 1996 with approx 30K on it. The motor swap was done by me, and I built the harness. I am running the 9693 ECM with a 91 harness from a 5 speed car. (Still have the Getrag). I may even be able to drop it off at your house, if you live between Virginia Beach and Chicago (Archies).
You can find most of my build threads using the "Search" and "3.4 DOHC" look for posts by qwikgta
I have about $3500 into the swap, and would like to get $2000 for it. Remember, this is a true Plug and Play. you will only need to do/buy a few things that need to be done anyway.
I am posting here first, to give you all first shot at it. Some of you install these into others cars. You may want to purchase it, and have it ready to plug into someones ride. Maybe you know someone who is looking. I really think that $2K is a good price for this. BUT, if someone wants to talk about it, PM me.
