87 Fastback L47 Chump Car/ Lemons Project.

[FieroWanaBe1]

Its huge, I haven't measured it.
somewhere around 1000in^3 is my guess

My reasoning for so big, see SAE 2008-01-3007, bigger was better by a great amount.

[The Dark Side of Will]

Its huge, I haven't measured it.
somewhere around 1000in^3 is my guess

My reasoning for so big, see SAE 2008-01-3007, bigger was better by a great amount.

Big plenum = more top end. Of course if you run through a single throttle and that throttle is outside the plenum, throttle response will be pretty terrible.

[FieroWanaBe1]

I really don't think my shimmed valve springs are going to cut it with these cams.
I've browsed Comp's master catalog and I think the 4.6L 32V mod motor springs are a match for the LQ1 motors. Stock specs seem identical to what I have seen on the internet for the 3.4L. I'm going to have to see how to make it work.
Both motors have 7mm valve stems. Cobra motors have valve seals that are also spring seats... Interesting obstacle

03-04 Cobra motor:
Valve spring free length intake 42.16 mm (1.6598 inch)
Valve spring free length exhaust 42.16 mm (1.6598 inch)
Valve spring squareness 2 degrees
Valve spring compression pressure intake 711.47 N @ 26.19 mm (159.9 lb-ft @ 1.031 inch)
Valve spring compression pressure exhaust 711.47 N @ 26.19 mm (159.9 lb-ft @ 1.031 inch)
Valve spring installed height 36.14 mm (1.4228 in)
Valve spring installed pressure intake 289.1 N @ 36.14 mm (64.99 lb-ft @ 1.4228 inch)

LQ1:
Valve Spring Free Length: 1.6551
Load (Closed)-All: 65 lb @ 1.400
Load (Open)-All: 160 lb @ 1.030

Comp Springs 26123, Ti Retainer 798:
Top - OD: .943 ID: .580
Bottom - OD: 1.105 ID: .742
Seat Load: 90 lb @ 1.47
Open Load 252 lb @ .970
Coil Bind .90
Rate: 324 lb/in

[FieroWanaBe1]

Valve Spring
1.680" length
1.1705" OD Bottom
0.8435 ID Bottom
0.968" OD top
0.631" ID top

Retainer
0.9825" wide
0.430" tall
D 0.583
B 0.506
A 0.9825

This data is from SappySE107 on 60degreev6.com
I'm going to pull my heads off to verify the Comp 26123 fits. If this is all true, I'm Going to attempt to use the comp springs and TI retainers on the DOHC. An article on 60degreev6 claims the SOHC springs will fit, but those rate are actually lower than the LQ1 factory.

[FieroWanaBe1]

Anyone know why IMG tags aren't working anymore?

[FieroWanaBe1]

Did some more math.
-The Comp 26123 would be around 67lb at the seat (1.400), but its higher rate would be 193lb open pressure (.390lift) with my cams, bind is at .500" lift.
-The Comp 26113 would be around 125lb at the seat (1.400), but its lower rate would be 200lb open pressure (.390lift) with my cams, bind is at .448" lift.
I wonder which one is lighter. Engine Analyzer is favoring the 26113 for dynamics. I need valve weights to get a better estimate of mass. I'm guessing based of SBC weights minus a few grams at this time. And I'm using 48g for the lifters, I think those are the weights of the ones I bought from WOT-Tech two years ago. I'll weigh everything when I get it out of motor for the change. Ti retainers being available is nice too.
Just need some MLS gaskets to be available and Ill bite the bullet on head studs too.

[FieroWanaBe1]

So, I guess I plan now on using my tax refund to rebuild the motor the right way.
Head studs, main studs, and .030 keith black pistons, "premium" rings, with a wider end gap, comp 26113 valve springs, ti retainers, and some bowl porting on the heads, SI valves. That way I never have to worry about skimping out a part and it failing on me. The corners cut have been bugging me, and I just want to take care of the things I know I should, I want piece of mind at 7500rpm right behind my head.
Full items then in the motor will be:
Clevite tri metal rod bearings
ARP Rod Bolts
King bi-metal 3/4 groove main bearings
Crank Scarper
SBC Cam bearings
.030 over hyper-coated skirt pistons
Steve long refurbished camshafts, 2 deg advance
3 angle valve job (60-45-30)
SI stainless Valves, back cut
lightweight lifters
Main studs
Comp Springs, Ti retainers
Mild port work on heads
Short runners in a box intake, 75mm throttle body
parts store oil cooler
and a full balance.
Then I will be comfortable to run this motor all day.

Anyways, chassis work continued over winter, somewhat. We have the fuel cell mount 90% done. We need to get it covered for the secondary fire containment, but I think it will be plumbed first. Money needs to be saved up for the holley hydromat for this 15Gal cell.
When IMG tags start working again ill put the pictures in.

[FieroWanaBe1]

Just found out today, SI Valves has discontinued the Valves for the LQ1.

[ericjon262]

are they an odd size?

[FieroWanaBe1]

Yessir.
Exhaust: 1.2600" Head Dia.; 0.2739" Stem Dia.; 4.1000" O.A.L
Intake: 1.4370" Head Dia.; 0.2742" Stem Dia.; 4.0910" O.A.L.

As far as I can see, Sealed power has replacement valves, that are not stainless.

EDIT:
The closest i have seen are for EJ20/25 motors, however they have a 6mm stem, not 7mm.
LQ1 valve guide specs: .2755 ID, .5118 O, 1.640LG

Im looking to see if I can find some universal guides to reduce the ID.

[Shaun41178(2)]

I guess you must want to run stainless valves pretty bad.

Are they lighter than stock and if so how much? I would try to find the weight of the wrx valves.

I don't see a need for stainless unless they are lighter and you are going for lightness on a budget(instead of ti valves) or unless you are gonna run boost or nitrous. That's just me though.

Def interested in following this build though

[FieroWanaBe1]

I was only set on the si valves because the rumor was they were lighter. The Subaru valves are most likely going to be lighter at a 1mm different stem diameter.
I'll just have to drop the valve upgrade portion of the new build up. I can still back cut the stock valves.

With the subaru valves and the need for custom guides, a solution for the dropping guides on these motors could have been conjured up at the same time. The right answer when going to stainless valves would be to run manganese bronze quides, since iron can gall on stainless, and the factory PM guides the LQ1 probably has are mostly iron. Aftermarket replacements are plain iron.
The subaru valves being slightly longer could help bring the lifter proload closer to stock as well.
I may have to look at one soon to compare, I have a few acquaintances who have blown a couple sti motors up.

Edit: grammer

[The Dark Side of Will]

Was thinking this is all sounding fairly expensive for a Chump Car/LeMons build.

[FieroWanaBe1]

I need to constantly remind myself to tow the line and err on the side of caution when necessary. Im always looking for the unfair advantage at the same time. Although interesting to me. The STI valves just arent in scope right now. Until a failute occurs.
But at that point maybe a 3500 is a better route.

[The Dark Side of Will]

With the parts available, I think a 3500 would be a better engine for a LeMons/Chump effort. Stock for stock a 3500 makes the same power as a TDC, but is 80# lighter... A cam upgrade is... what? 30 HP?

Also, I haven't been to a junkyard in a while, but I suspect that 3500's are FAR more common in yards than TDC's at this point.

[FieroWanaBe1]

Last year while browsing they were like 250 for a 80000 mile unit on car-part.com

[ericjon262]

there's also the 3400's, the 3500 does have better heads stock, but ben at WOT-tech claims he can port the 3400 units to flow better than ported 3500 heads. also, the 3500 uses a unique crankshaft trigger wheel, you will either have to go with an external wheel, or remove the crank to install a 7x wheel.

[FieroWanaBe1]

I dont have to use the 7730 to run a 3500 either... There is the option of OBD II or other ecus that dont reqiure a GM DIS coilpack.
A 3500 would only be after this motor catastrophicaly explodes.

[ericjon262]

I dont have to use the 7730 to run a 3500 either... There is the option of OBD II or other ecus that dont reqiure a GM DIS coilpack.
A 3500 would only be after this motor catastrophicaly explodes.

10-4, FYI though, even if you were to use the oem computer, I don't think anyone has "unlocked" them for tuning, which sends you back to 7730/ external trigger. there was a guy a couple years ago working on setting up an LX9 with megasquirt using the stock trigger, but I'm not sure he ever got anywhere with it, but I don't see why it would be impossible.

[The Dark Side of Will]

HP Tuners doesn't do them?

There's nothing wrong with the coil pack. It works fine. In fact, for aftermarket ECU's it's a pretty easy solution as it provides logic level triggering signals and only requires one ignition output from the ECU.

Also, isn't port work pretty expensive for a LeMons/Chump car?