3.3 turbo issues.

[quattrorunner]

Soooooo,
6 years ago I spun out and didn't push in the clutch In time to prevent engine going backwards. I pulled the car off the road to do a backdate and now go to restart and find this issue. Sounds fine as far as no funny noises but it does sputter and backfire. Also some cylinders are not igniting properly.
So it's time to open up.
I want to add power. My current cam is sc grind and I'm thinking gt2 evo and maybe add larger turbo to gt40 up from gt35. Currently my power tune isn't even done but I was having reduced power above say 5500rpm. This is why I want to try another cam but the tune is also suspect. Beside the point of this post.

What I'd like are some recommendations while I'm doing this?
I'm considering twin plug
Also cam
Also upgrading valves and springs?
Engine is Carrera based unsplit block with JE pistons and turbo cylinders. Efi of course, half bay bell intercooler.
This engine is probably 5 hours fresh.

[gsxrken]

Free bump for ya. I’d want to do a leak down to determine you really did bend some valves, otherwise why crack the motor open. Twin plug is always encouraged as well as some intake porting if you’re really going to step on the engine like you sound like you’re planning to do. Most people don’t outgrow the GT-35! Ask Chris Carrol for the right cams and good luck… can’t wait to see this dyno sheet!

[quattrorunner]

Thanks for the bump and hint.
I will do a leak down and report.

[quattrorunner]

As an update.
I did partial leakdown testing finding really confusing results. At 100psi my loss was like 80%. So I borescoped the chamber and couldn't see anything wrong. My scope couldn't see the valves but nothing on the pistons. My plugs wet and smelt of fuel.
I haven't been able to test or even look at all cylinders time kept me from that. I did drain the oil in prep for removing the valve covers and the oil smells of fuel so good I change anyway.
Last night I woke thinking about this...
It seems likely to my unknowledgeable brain that maybe I skipped a tooth? My timing might be off causing a bad running condition?
What say you? Keep in mind the car spun and may have gone backwards before pushing in the clutch.
I had been thinking valves bent but I don't see evidence of that.

[Alan L]

80% leakage - where is it going? - should be obvious. Should be able to hear it. If it is out the exhaust then ex valves would be suspicious.
80% leakage on all cylinders tested?
Skipped a tooth? You can check this with the engine in place. A visual check would be close enough for this purpose - you are looking for 1.5+mm deflection on the I valve at TDC #1 and the corresponding same on Z4. You can guesstimate that much by observation. Saves the hassle of rigging a dial gauge in there (but it is do-able).
If you have bent valves, the clearances should be well off.
Edit . Are you sure you are doing the leakdown right? Z1 (#1 firing, not #1 timing). If you are on the timing #1 you will get something like 80% leakage - both ends-valve overlap.
Alan

[quattrorunner]

So here is what I have.
At tdc the issue of leakage is there for cylinder 1. And the cylinder is at tdc as visually verified.
But the valves don’t hold pressure till 120degrees past tdc for cylinder 1. Leak down is only like 10% or less even that far away from tdc.
So timing looks to be a real problem here. Am I right?

[Alan L]

But which TDC? You have 2 . TDC firing - this is where your leakdown should be tested. All valves should be closed. And TDC timing. Here your I valve is cracked open to your timing setting, and the E valve is probably not quite closed (overlap). Both valves open here and the I valve stays open for a good distance of travel (120 deg?)(while the E valve is closed.)
You have to determine which TDC you are on when testing leakdown. Take the top valve covers off. This will tell you which TDC you are on. And tell you if you have jumped a tooth.
You could also pull the dizzy cap and look for the #1 firing mark as you hit Z1. That will tell you when #1 cyl is ready for leakdown test. The I valve rocker should be slack.
Alan

[quattrorunner]

Thanks again. I’m not sure. I have cop so no dizzy. When I’m back into town I’ll check again. What I did do tho was to keep the pressure on till it stopped leaking. This could indicate I was on the wrong stroke.

[Alan L]

Yes - I am guessing wrong stroke. In which case to be sure - you need to take the valve covers off (no dizzy). That will also tell you if you jumped a tooth.
Or.... you can go to Z1, test #1. If 80% leakage , switch test to #4, without moving crank. My guess is you will get 10% or less. You have to know which cylinder the Z1 mark is referring to basically.
50% chance. Because you have 2 TDC cycles.
Alan

[gsxrken]

Originally Posted by quattrorunner

But the valves don’t hold pressure till 120degrees past tdc for cylinder 1. ?

The fact that you hold pressure at 120° past the mark and not some random number suggest that you have the wrong TDC. If you jumped a tooth, I would think it would be some number not exactly 120 that works. But it should be easy enough to check when you get back there. Do you have a simple compression gauge? If you removed all the plugs and tested it that way and reported the numbers here, we could probably determine if your peak numbers are OK, even if they are even across the board.

I’ll be curious to hear the resolution. You’re sputtering and backfiring, so something is wrong. But it’s been six years of sitting, so it may not be a mechanical thing. Bent valves often don’t even return to fully seated, and the engine probably wouldn’t start. On the other hand, one skipped tooth might not bend valves. Backfiring is often timing related. Might run like crap but I would think it would be pretty difficult to start. Maybe your EFI cam timing sensor situation shifted. So we need to keep digging.

[quattrorunner]

I had no idea the valves were cracked thx for the second stroke. Learn something everyday.

[Uwon]

Originally Posted by quattrorunner

Soooooo,
6 years ago I spun out and didn't push in the clutch In time to prevent engine going backwards. I pulled the car off the road to do a backdate and now go to restart and find this issue. Sounds fine as far as no funny noises but it does sputter and backfire. Also some cylinders are not igniting properly.
So it's time to open up.
I want to add power. My current cam is sc grind and I'm thinking gt2 evo and maybe add larger turbo to gt40 up from gt35. Currently my power tune isn't even done but I was having reduced power above say 5500rpm. This is why I want to try another cam but the tune is also suspect. Beside the point of this post.

What I'd like are some recommendations while I'm doing this?
I'm considering twin plug
Also cam
Also upgrading valves and springs?
Engine is Carrera based unsplit block with JE pistons and turbo cylinders. Efi of course, half bay bell intercooler.
This engine is probably 5 hours fresh.

After 6 years sitting, you may want to consider a partially clogged injector. I would try pulling the plug wires one by one while idling. M2CW

May I ask what EFI system you are running and what type of timing pickup you have installed?

Insofar as wanting more power, I do agree with you that the tg35 runs out of umph. In my case it starts 500 rpm later at 6k and I think that my big wide intercooler my have something to do with it.
If you are going for twin plugs, then consider wiring coil switches for cylinders top 1-3 and bottom 4-6 on one and top4-6 and bottom 1-3 on the second switch. This will help you diagnose plug and plug lead issues easier.

Cheers,
Johan

[quattrorunner]

Thanks Johan.
I know this sounds dumb but I had these symptoms 6 years ago (after the accident) and subsequently checked all my injectors because I figured they were the issue before I quit trying to sort that out. I then forgot about that issue when I started pulling the body apart and now remembering it all again now. The injectors would be fantastic if they were the issue. I will do a quick check as I still have my injector test apparatus. But I doubt that is it.
My ecu is electromotive gt200.
My pickup is on the pulley. I can’t remember the specifics but it’s Clewett’s. It may be off I haven’t checked.
I think the gt35 is pretty good. I hate to throw it under the bus. I haven’t made 500hp yet. But I did huff and puff at higher rpm’s. I don’t think it’s the turbo. My last engine a 76 3.0 turbo used a gt30r and it was awesome all the way to redline like pulled hard till the engine rpm and sc cam became the weak link. My issues are probably tune and cam maybe.
I will choose twin plug if I need to pull the heads but I won’t till later if not. I want to drive this car again so I’ll go the quick route but I still want cams. I c gg penal good upgrades with the efi. I have the sequential spark, I have all the goodies if I remember right. I do know there are many who boohoo the electromotive which sux but I think I can get it tuned. It has all the adjustments and capability.
I’m headed home today and won’t get to this again till tomorrow night. We’ll see.

[Uwon]

I think I had the Electromotive GT 200 back in ‘98 or so. My Indy at that time (before I started doing my own work) convinced me to “move up” to the Electromotive tec3r. I like the tec3r and am only sorry that the company is no longer with us. Honestly, can’t remember if I noticed an improvement with the tec3r….I was just too busy making money and anticipating my next weekend at the track.
I do remember the first time I had the car on the track at Mosport with my ‘new’ custom wide intercooler….just blew everybody away up the long uphill back straight…..in the heat of summer. I then had the old 7006 turbo modified for earlier spin which improved low end acceleration out of the slower corners. Well, this old turbo went through too many rebuilds and then I retired from DE weekends so I moved onto the GT35, which has excellent lower end response for normal road driving but no match to my old modded 7006 at the top end of a long upward stretch. Nevertheless, I do believe that a big intercooler will give you the best bang for the buck…..easier to control idle and low end cruising without spitting and farting and great cool air as you boot it for that big grin.
Cheers,
Johan

[quattrorunner]

Ok so my issues are NOT mechanical. Tonight I pulled the covers off and while doing the initial valve adjustment after rebuild I also leak tested every cylinder. I have like 2-3% max leakage. While I was in there I looked over the working from the crankfire pickup. Everything looks ok. Tight and no damage that we can see. But, I still might be Off if my Clewett pully is adjustable? It looks solid tho. Here is a picture of leak down(same on all cylinders) and also a peak at the pulley and position of the trigger wheel at the gap.

I am going to test all my injectors again. It’s been a long time since it’s been run.

[Uwon]

You should also consider a telephone call to Richard Clewett. He is my go to expert with anything electronic. He helped me diagnose a nagging sensor issue number of years ago by logging into my laptop remotely.
Please keep us updated.
Cheers,
Johan

[mikedsilva]

Originally Posted by quattrorunner

Is that fan belt on inside out??

[quattrorunner]

It is! I have no idea how that happened. And it was damaged too. I’ll get that fixed before I get everything back up and on the road.

[quattrorunner]

Tested the injectors and they're good. Richard Clewett mentioned fouled plugs. I'm going to button it all back up and put fresh oil in, clean the plugs gap them and try again. I'll put my laptop on her and see what the codes say.

[quattrorunner]

Fouled plugs.
Engine is good and runs fine. Duh.