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Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:01 pm
by 88a5tq
Thanks for the encouragement. Looks like I'll be doing my first headgasket job. Gotta beat the snow so better get moving hah. BTW, log looked normal. Fuel was fine at around .80 maybe .79 and that was with my meth injection. Fuel adjustments worked out well but this was quite a surprise.
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:03 pm
by pilihp2
How many miles are on it? Probably was just a tired HG to begin with.
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:08 pm
by 88a5tq
Maybe 140K. My odo died 6 months ago and I live at work but I think you're right man. Any recommended part sources for these gaskets? Quick look showed $300 for kit.
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:09 pm
by AngryTaco
Perhaps it's my lack of experience with aftermarket ECUs (I'm used to tuning my JTEC factory ECM in the Dodge and others for that matter via SCT) but why would the ECM or VEMS be at fault for the flywheel? This is a serious question btw.
It's no secret about my opinion that 034 makes and sells crap components (there's a reason I sell awesome motor mounts) but wouldn't the liability fall on 034 because of their cheap design? Hell you can buy the friction surfaces from JEGS or Summit. It's just generic pieces aside from the machined Aluminum flywheel.
Just looking for an educated answer here. Perhaps I didn't read far back enough. Curiosity looking for a solution
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:11 pm
by AngryTaco
88a5tq wrote:Maybe 140K. My odo died 6 months ago and I live at work but I think you're right man. Any recommended part sources for these gaskets? Quick look showed $300 for kit.
Hardly. Headgasket shouldn't run you more than $80 online. If you don't have studs, I seriously suggest you pick up a set of ARPs (torque to 80 ft-lbs). If you don't, this is most likely WHY the gasket blew at your power level.
Total job shouldn't run you more than $150 honestly (not including the studs)
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:18 pm
by Aktapod
Dang... Bummer, dude. For once, I have to agree with Jared. Take some time off and come back to it when you're ready again. The car will be waiting when you're back on your feet.
Plus, soon you'll run out of stuff that go wrong, right? *knocks on wood trim
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:19 pm
by 88a5tq
Probably like 4k less than that cuz I barely drove it because of that whole "event" last month.
Its cool. I bought the new ECU and it arrived at my doorstep with the fuel pump FET ground strap touching #5 injector FET's ground strap. This caused hydrolocking everytime I would crank the engine because the fuel pump FET was also powering the injector FET with 100% duty cycle via uninterrupted voltage supply. It was never going to run and could have destroyed any number of things right out of the box. To me they think they're off the hook because of this "diversion." The flywheel gear wouldn't have broken to begin with if the VEMS ECU FET straps weren't physically touching. Just cause and effect for me. Paid $1400 for that box of electronics...
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:31 pm
by AngryTaco
Ok now I understand. While I am inclined to agree with the inferior metal part, I now see why this would be VEMS fault. I suppose 034's cheap design saved you from worse damage such as a bent rod (I have hydrolocked my 20vt and bent a rod before -- drove it for 2 weeks before figuring it out -- don't ask why, it's a long and embarrassing story).
However, none of that damage, theoretically, would have occurred if it were not for the defective ECM and I do believe your argument would hold up in court should you decide to persue legal action.
Take some time off from it and take a breather
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:32 pm
by AngryTaco
Aktapod wrote: For once, I have to agree with Jared.
20v rulz
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:39 pm
by 88a5tq
Lol well im rockin the 20vt again for another 2 weeks at least now. Thanks man. For awhile there I thought I was losing my mind as everyone I spoke to about that thought they didn't owe me shit and I was just annoying them.
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:51 pm
by pilihp2
My roommates honda civic just blew the headgasket as she was driving down the road and poured oil into the coolant, and coolant into the cylinders, and continued to bend a rod. So I mean. It could be worse, right?
Now myself and the 2 other dude roommates get to replace a civic engine while she's in europe for 6 weeks, instead of work on our own cars.
So I kinda feel you, dude.
Re: Julian's '91 200 20vt
Posted: Thu Sep 25, 2014 11:59 pm
by AngryTaco
stick a turbo on it and tell her it's an anti-water log adapter. Video tape the reaction.....PLEASE
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 6:25 am
by 88a5tq
Lol...
Jesus I hope the rods are oK (on mine)
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 6:34 am
by 88a5tq
Do I need to remove the IM & EM and turbo to sand/deck the head if I do it myself? I remember that guy doing it himself on a huge piece of glass. I have a feeling shits gonna be warped...
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 9:02 am
by AngryTaco
If you overheated it then it could be warped. Either way if you havent done it before, bring it to a machine shop and have them go through the head. Exhaust valve guides may need replaced at this point so perfect oppurtunity. Guides, fresh valve job, surfacing or mill operation shouldnt run you more than $200, $250 with intake and exhaust guides
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 12:01 pm
by loxxrider
I'm very curious to see what the pistons look like. This kind of gasket failure doesn't just happen randomly on a perfectly healthy engine. I ran 25psi out of my holset for years on the stock 170-180k hg and stock head bolts. By the way, hitting boost cut is not harmful for your engine. I can't tell you how many times I did that with mine over the years.
Anyway, I suspect this failure was due to det somehow, meth or not. Either something got too hot or cylinder pressure was too high (head lift), or both. Take good pictures when you get the head off, especially in the area where the failure occurred, spark plugs, and piston tops. Good pictures meaning close up and in focus

Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 12:47 pm
by GTJeff
So how do you guys with VEMS detect det? Do you have to resort to one of those Saab APC knock boxes and/or knock phones?
And also why is seemingly such a hastle to control the wastegate to acheive the boost levels that you want? Is it normal to have boost creep or whatever in cold weather with the VEMS ecu?
My ancient MC ecu with a processor dating back to the late 70's and a few mods will both indicate knock and control boost perfectly to whatever I want it to be.
There is probably something that I am not understanding but I don't get why customers would tolerate such limitations in these state of the art stand alone systems.
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 12:55 pm
by EDIGREG
Regarding det, yes, you tune the car using knock phones. VEMS does provide knock detection, however, a ton of noise comes through a knock sensor. Filtering out all of that noise to detect knock is incredibly difficult, and is different for every engine/sensor combination. Universal devices such as SEM ECUs or knock boxes attempt to use a knock-detection algorithm that "works" universally - these will never function nearly as well as as an engine-specific factory ECU which has gone though thousands of hours of R&D for the safety of that specific engine.
Regarding boost, VEMS can control boost very precisely when tuned correctly.
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 1:02 pm
by loxxrider
GTJeff wrote:So how do you guys with VEMS detect det? Do you have to resort to one of those Saab APC knock boxes and/or knock phones?
And also why is seemingly such a hastle to control the wastegate to acheive the boost levels that you want? Is it normal to have boost creep or whatever in cold weather with the VEMS ecu?
My ancient MC ecu with a processor dating back to the late 70's and a few mods will both indicate knock and control boost perfectly to whatever I want it to be.
There is probably something that I am not understanding but I don't get why customers would tolerate such limitations in these state of the art stand alone systems.
Knock control has always been a struggle for VEMS and 5-cyl. They always talk about getting it implemented, but I haven't seen it yet. I don't know why. They probably just don't have the time to dedicate to getting the proper filtering involved. Still, it shouldn't be anything to worry about with a proper tune.
As far as boost control is concerned, that is not a limitation of the ECU whatsoever. VEMS actually has very good boost control logic in my opinion. It is user incompetency that makes it a problem. That is the reason I'm writing up the boost control DIY here. No it is not normal to have any kind of boost control issues with a properly set up PID scheme. Since VEMS is not tailored directly to the 5-cyl and N75 WGFV, it does not have the proper parameters input for good boost control installed form the get-go. Having a boost controller which could be used for any engine or even for the same engine but with a different turbo setup is very difficult and requires an expert in controls and possibly more processing power than the VEMS guys are willing to dedicate to boost control. The reality is that someone knowledgeable about PID tuning should be able to get the boost controller tuned in a few minutes while street or dyno tuning the car.
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 1:06 pm
by 88a5tq
My problem was I used 100% DC clear up to 3500 rpm when it should've started at 80% instead of only as early as 4000 rpm. Otherwise its quite good. I don't give out compliments on this stuff anymore though. I have stubborn views.
Chris, last night your posts had me feeling better. Today, beginning with your detonation post, you're scaring the shit out of me haha.
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 1:24 pm
by 88a5tq
BTW this junker is back home now. Its my $500 car with almost $5k invested lol. I feel sick. If it detonated, the flywheel job will be in vain cuz I picture crank removal if that's the case unless I don't need to when removing the offending cylinder's rod.
My question tho is do you guys think I should fill the reservoir with water and attempt to start it?
I don't know anymore. I do have a spare engine though with an intact HG I could steal the head off... Even has the new can seal mine needs. my coolant temp gauge was was at TDC for coolant when I looked and drove half a block coasting to pull over. I hope its not warped or anything...
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 4:02 pm
by 88a5tq
Log from HG failure, 3rd gear pull
Strange, ARP studs are $50 more on the company's website compared to 034? WTF that cant be right! Better order pronto.
Re: Julian's '91 200 20vt
Posted: Fri Sep 26, 2014 6:31 pm
by yodasfro
ARP head studs are cheapest off ebay ARP 204-4207 $146 shipped The HG set is cheapest from autohausaz or pelican parts both will get you free shipping 034198012M $118
http://youtu.be/LVPNXsc4wsQ
Re: Julian's '91 200 20vt
Posted: Sat Sep 27, 2014 7:35 am
by PRY4SNO
loxxrider wrote:Having a boost controller which could be used for any engine or even for the same engine but with a different turbo setup is very difficult...
So, the Synchronic WG that I bought has a built in boost controller with 6 different settings.
http://www.synapseengineering.com/v4/wg/I'd assume this is along the lines of what you're referring to?
Re: Julian's '91 200 20vt
Posted: Sat Sep 27, 2014 7:52 am
by 88a5tq
Thanks yoda. I had an RMA from the ring gear they had me buy first off (bad idea) so I used that store credit to buy the ARP's. Do I need anything better than the stock metal HG for my low goals though? I don't really see myself going MLS at this point. I just want to throw the other head on it to get it back on the road pronto. My understanding so far is the head studs are the primary concern here. My spent HG is likely original too so a younger gasket may be just fine here.
PRY4SNO, that movie is gonna be awesome when it comes out! Ill see it in theaters. Cool preview video on their website

. That's a badass product though.