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Old 01-31-2008, 11:43 PM   #1
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Default L27 Modding/Rebuild

So I have a few ideas for the rebuild coming up within the next two weeks. And I'll probably continue the project'* progress in the current thread in Gen Chat but I wanted to make a separate thread for the questions pertaining to the performance stuff.

Just some info to get out of the way, I have about $500-600-ish to use for the rebuild. I would like to break into the 15 second range in the 1/4 mile as well, though considering how bad my old motor looked, this one alone might make it there on its own . Anyway, A Crank job is #1 on the priority list as that is the whole reason for the build. Turning the crank should go for about $70. While we're at it the cam bearings will be replaced as well as a safe measure that'll be about $60-ish I'm told. Of course some gaskets and oil. Stealing Rods from the other motor, Free. And several cans of paint .

Ideas/Questions:
1.) Transmission: Planing on getting the shift kit, since well, sine the trans is going to be out of the car and now is better than ever for it @ 161k. Is the TransGo Jr. Shift Kit a rebuild kit too, or would I need to purchase a rebuild kit as well. (At the moment I do plan on tackling this myself, with the aid of my dad if needed, and you all of course. And Brad, you mentioned something about a Manual/Book for the trans rebuild when we picked up the car last weekend, what was it again?)

1.5.) Remote Trans Filter: Its also on my list for this build.

2.) 1.8 Rockers: Though they are half my budget they may not come in till later (Maybe Intense will be selling them by then), and I believe I did need a new Cat for those anyway. But, would anything else be necessary or required to run these. I have heard/read both to keep my stock push rods & springs and also heard I might want to invest in stronger valve springs, whats stock and what should I look for?

3.) O2 Sensor: I was told something about a conversion, 3-wire to 4-wire? Whats the benefit/reason for this?

4.) Injectors: Mine are nasty, so they'll be cleaned. I assume Cleaning and Flow Matching are different? Whats the advantage to Flow Matched. And Whats stock for the Injectors size on an L27. They don't happen to be the same as L67 injectors do they? Any advantages to having bigger injectors on this motor as it is now or no?

5.) Magnaflow Cat: Its going in, period (probably not till after she'* back on teh road though)

6.) Jet Chip: Is moving farther down my mod-to-do list, as the GM Tuners is rising.

7.) Porting: What should I go after, or look out for when doing this? My EM'* are perfect (The front is anyway), Thanks to Brad.

8.) CAI: Mine will actually be a CAI soon, I have had the material to shield it since i got it but I only just found a single washer fluid bottle so now I have room for that.

9.) Anything else you think I could do, idc how much, any ideas will be accepted, as they may come in down the road if they don't fit the budget now.


Sorry for a ton of questions at once but Thanks in Advance!
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Old 02-01-2008, 08:03 AM   #2
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1.)You will want the ATSG book for the 4t60e. Your FSM will also have alot of good information, but NOT up-to-date information (like updates to the transmission parts and procedures). Specialty tools will help, but not required. You MUST set the trans upright for most of the build, so a fixture will have to be fashioned or alot of cinderblocks to set it on.

1.5.)Not hard to do. I have yet to do mine, so I am not sure on the best spot to mount it. This is something that can be done much later. In fact, don't include it in your current budget. No point in doing convenience upgrades until your drivetrain is 100%.

2.) See my above comment. You do not need to do this yet, as this can be done with the motor in the car. Plus the PCM will need a new calibration to make the full use of them.

3.) The conversion would be mainly for availability. From what Don told me, 1993 was the ONLY year for 3-wire sensors, meaning they tend to be more expensive than any other of our sensors. Conversion should be reletively simple...just follow the schematics.

4.) Yes, cleaning and matching are different. With matching, you will need more than your current 6. Where ever you take them to, they will match up all the flowrates of the injectors to a certain percentage (so that all of them are flowing equally). Since you have Rochesters, and I have seen new ones go for a song on Ebay, you may want to check there after you get prices on services to your old injectors.

5.) Yup.

6.) Yup too. For now

7.) You left your old intake mani here. You could have used that to port and polish those runners (that is where you will make some power). I never installed my reworked intake as it wasn't, and still isn't done. It'* almost done though...just on the backburner. I cleaned up your ports in the heads a little bit while they were off, so you should be good there. Wren mentioned something about the manifolds actually not needing to be opened up on the S1s, so for now lets leave this alone. You are already flowing more than most due to the cleaned valves

8.) Again, yup. But for even MORE room, find a '96-up bottle.

9.) I can't think of anything else. If you want longevity out of this new motor, I suggest an oil cooler. Find an S1 L67, snag it'* filter housing, and run all new lines to a cooler up front.
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Old 02-01-2008, 01:04 PM   #3
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Default Re: L27 Modding/Rebuild

1. Trans. If you've never done something like that, hire a pro. Yes, that'* the right shift kit, but you also need a rebuild kit and you'll need an additional hard part or two that you'll discover after you crack the case.

2. Rockers will be the best bang for your buck. Contact INTENSE about being the first test car and see if we can get them going.

3. No benefit. I run a single wire O2 on the Zilla and I do just fine.

4. Not the same as L67. 19# if I recall. You'll need at least 12, as FIE has none in in the pool for the L27. Advantages are in fuel mileage and HP. It wouldn't matter if you had six O2 sensors. Does that explain it well enough? Some are lean, some are rich, your O2 pulses them based on the average of all 6 that the O2 sees. Cleaning, rebuilding, and flow matching are all different.

5. Magnaflow cat? Good. Do it.

6. Don't underestimate the Jet. It'* STILL serving me very well. With GMtuners, you better know exactly what you want. Contact them for the 'list' of parameters and look it over before you dump the Jet idea.

7. LIM only. Head porting isn't for the average joe garage wrench. It'* a spooky proposition. Far spookier than I made it look last winter. Do the LIM, ignore the EM'*
http://www.bonnevilleclub.com/forum/...ic.php?t=80339 The only thing you should do is fix any cracks and lightly 'kiss' any imperfections or blockages. That is until you port your heads of course.

8. CAI. Excellent idea turning a WAI into a CAI.

My recipe for your success would be the CAI, Cat, port the LIM, and do rockers. From there, make your decision on which PCM.
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Old 02-01-2008, 07:51 PM   #4
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Default Re: L27 Modding/Rebuild

Quote:
Originally Posted by 93-SSE
1.) Transmission:...At the moment I do plan on tackling this myself, with the aid of my dad if needed, and you all of course.
Ok, you do not want to do this, trust me on this one. I've done the 700R4/4L60E, which is more straight-forward by comparison, but I would never be foolish enough to do a complete overhaul myself again. It'* just not worth it when you can get a shop to rebuild it and warrantee their work.


<snip...>1.5.) Remote Trans Filter: Its also on my list for this build. <snip...>

Not really required IMHO, since the one in the pan is enough filter for the transmission. Better approach is weld a bung and a drain plug on the pan, then change the fluid/filter on a regular schedule.



<Snip...>I have heard/read both to keep my stock push rods & springs and also heard I might want to invest in stronger valve springs, whats stock and what should I look for?<snip>

Bumping the rocker ratio requires checking the clearance on the springs, and in the case of a 1.8 ratio, probably will need the springs changed along with the seats machined to provide both enough pressure on the valve train and enough room to prevent coil bind. Are you bumping up the RPM as well ?

Oops..better finish this, Pizza man is at the door!
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Old 02-01-2008, 07:57 PM   #5
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YT 1.8 rockers require no valve spring change or pushrod length change. They will clear with stock components.
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Old 02-01-2008, 09:03 PM   #6
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I think that you are going to find that your budget is a little low for what you want to do. I just went through it on my L36. I spent about $1100 on the bottom end alone. The block was hot-tanked, magnafluxed, honed, new freeze plugs, new cam bearing, and new counter shaft bushings. The crank was ground. The rods were reconditioned. New pistons and clevite bearing throughout. I wasnt willing to take any risk on the bottom end. Then about another $900 into the top end with the heads being sent out for a valve job and hot-tanking with new seals. New UIM. I ported the heads and LIM while the bottom end was at the machine shop. I hvae about $2000 into parts and machine shop labor alone. Plus another $900 into the trans. $800 of that was parts. My local tranny guy did the rebuild for me for $100 (nice to know people ) Be prepared, because it can get EXPENSIVE really quick!
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Old 02-02-2008, 08:50 AM   #7
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Quote:
Originally Posted by willwren
YT 1.8 rockers require no valve spring change or pushrod length change. They will clear with stock components.
Hmmm... So what have you found the limit of valve lift before coil bind to be when using stock springs? When I reassembled my heads, I didn't check to see how much lift was available before binding, I was just checking to see that I had the clearance on the stock rockers and cam.

I'm just thinking that a better approach to just putting on higher ratio rockers might be to put a higher lobe lift cam in first with stock rockers. What I came up with was 0.428" on the intake using stock cam/stock rockers. With a 1.8 ratio rocker, that would become 0.464". With a Comp Cams 246HR10, you would be at 0.480" intake/0.496" exhaust on stock rockers. (exceeding the lift of the stock cam/YT 1.8 rocker combination)
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Old 02-02-2008, 11:29 AM   #8
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I should add that, as far transmissions go, 1993 was a transition year for alot of parts. My SSEi trans had a mishmash of the old and revised pieces, and I only reused a few parts in the new build.

I didn't just jump in and start my rebuild on it either. I bought a 1995 Riviera trans off of ebay for 100 bucks if I remember correctly, and I had planned on just shoving it in and deal with the repinning. But after discovering the mounting bosses were damaged, I had little choice in tearing it down to transfer to another case. And in doing so, I learned a great deal on what and how things go together and how they work. The biggest thing I had going for me was time...I was in no hurry to get it done, so I could afford to take my time, get the parts I needed, and study the ATSG. I won't say it'* a simple and easy job to rebuild one, and if this is going to be a daily driver, then yes I suggest a shop do it for you. But (and this is a big but), if you WANT to do it on your own, find a nice decent core transmission, and practice on it. Dissect, inspect, reassemble, repeat. Or get a nice used trans with a warranty, swap it out, and dissect your old one just to get an appreciation for just how much work is involved in getting all those small pieces to fit properly.

It'* not hard to rebuild, but it is very tedious and requires following the instructions to the "t".
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Old 02-02-2008, 11:35 AM   #9
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Stock springs for the Series 1 are 80# (higher than the stock S2 valvespring) at the
install height of 1.7". I measured this with a calibrated load cell and a used Zilla
spring as well as a brand new OEM spring.

Further specs on the OEM springs he has in his car at different heights:

80 @ 1.7
127 @ 1.6
155 @ 1.5
192 @ 1.4
245 @ 1.3
377 @ 1.2 (coil bind)

(again, these were measured by me, not looked up somewhere on the internet)

Curt, the YT rockers absolutely work perfectly (and were designed to) with stock springs, lifters, and pushrods. My new springs coil bind before the stockers, and they're still fine. There are hundreds (if not thousands) of L27'* on stock springs in the Holden market down under running this combination just fine.
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Old 02-02-2008, 05:20 PM   #10
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Well I have alot of consideration to do, I have a bit of time before we can get busy on the project though, about a week or two. Having a warranty on the trans is something to really consider as well, that be be the route we go with it.

I'll sit down and layout all my options sometime this week, figure estimates for each. Locate/scope out the local JY for misc. stuff.

Another question, What are the learning capabilities of the PCM?
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