Top end rebuild/performance upgrade questions??

[DerrickfromNC1]

Just did my mockup as suggested and my dh came out to approx .062. I didn't have a sophisticated dh tool so I bolted the cylinder down and used a straight edge and feeler gauges.
Im thinking I need to add some .020 shims and order the L3 heads with 51cc to get a target 8.3cr.
How does that sound?

[[email protected]]

Your current DH is perfect, don't shim it any more! Order the heads with chambers so you get your target CR and you are set. Just re-do your math with .062" DH instead of .082".

For a 88x69mm engine targeting 8.3:1, with .062" DH, you need 48cc.

[DerrickfromNC1]

[DerrickfromNC1]

[[email protected]]

then if you plan on a 88x74mm engine, a 52cc chamber gives you 8.3:1 then. And it gives you 7.8:1 now. Not bad. So get 52cc.
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[DerrickfromNC1]

My L3 heads from Aircooled.net arrived on Tuesday and I'm ready to start putting it back together. Can't find any decent 36 dells for under $500 that includes everything needed to install and won't require rebuilding. I'll probably purchase a set of the 3rd gen HPMX 40s which can be at my door for less than $650.

The ones I've seen come:
28 vents
200 airs
115 mains
52 idles

These should work for my engine but I'll probably purchase some 110 mains and 50 idles just in case.
Since EMPI has come out with their 3rd gen HPMX how can I tell whose still selling the older models and who has the 3rd gen?


Thanks

[DerrickfromNC1]

Finally got it all back together, in the bus, and running. Just to recap so you don't have to go to the beginning of the thread. The engine started as a stock 1600 which was in the bus when we purchased it a couple years ago that I pulled to clean up some oil leaks and do some top end upgrades. Here is how the engine is currently setup:

88mm thick wall slipins(Kaddyshack)
LN3 heads(aircooled.net)
Stainless steel 38mm sport exhaust(Monkeynuts)
009 with pertronics and Bosch blue coil
40 HPMXs(Carcraft)

I've gone thru the carb adjustments, best lean idle, syn, etc. When I first fire it up it idles smoothly but coughs thru the carbs a little when I attempt to rev it until it warms up which I assume is due to the low 40 degree evening temps and no chokes....after about 30sec it revs smoothly. When I take some test drives up and down the street it has a nasty little hesitation just off idle to the point of almost dying b4 it starts pulling. If I keep the revs up when shifting I don't notice the hesitation. The 009 was on the original engine with the stock pict34 and I did not have the hesitation. The carbs setup as follows:
28mm vents
52 idles
115 mains
200 airs
55 AC pump
Plugs(ngk BP6ET) look to be a little rich so I don't know if I should go bigger on idles. I'm wondering if I'm getting the dreaded 009 flat spot even though it wasn't evident with the solex. What are your thoughts?

Thanks

[Dr OnHolliday]

009 flat spot is a myth
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1965 Type 1 sunroof Baja / about 70k miles on self-rebuilt '74 1600 and counting / SP heads and aftermarket valve keepers / non-doghouse shroud with external cooler and filter / 1.5 qt extended sump / Weber 32/36 DFAV progressive carb / 009 dist with Pertronix / 1.25 ratio rockers and ball adjusters / 1.5" stainless steel J-pipes and carbon steel baja exhaust

[vugbug68]

Check the accelerator pumps, I had one set of brand new hpmx with one of the pump diaphragms flipped around so that carb didn't squirt.
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71 Super - Backroad Thrasher
66 Corvair - Weekend Cruiser
90 4 Runner - Muddin

[66brm]

Sounds like your synch is out a touch on throttle opening, they may sit ok at idle but open slightly leading one before the other, also check lean best idle if your plugs are dirty/fouling at idle. Also you could probably down size on the idle jets to a 50
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[mark tucker]

[DerrickfromNC1]

I found a set of 55 idles locally that I will tryout, but 1st I'm going to disconnect the linkage and start from scratch to make sure the carbs are in perfect sync. If this doesn't work then I will go rich with the 55 idles per Mark and Roy. If this solves the dead spot off idle then I will consider this a temporary fix.
I have a 2nd 009 that I may tryout b4 I go rich on the idles.

[DerrickfromNC1]

[66brm]

Its to do with the linkage, normal tuning rules still apply, synch and LBI with the linkage disconnected from the carbs, this shouldn't be touched again. Then with the engine off, connect the linkage to both carbs, and adjust the linkage only to ensure the carbs are closed and sitting on the idle speed screws, DO NOT ADJUST THE SCREWS TO ACHIEVE THIS. Now comes the tricky bit.....

You need to watch both carbs at the same time and actuate the linkage 1-2mm from the idle speed screws, do they have the same gap at the same time? Is the linkage leaning on one carb more than the other? Is the linkage leading one carb before the other?

If the answer is yes then you need to adjust the linkage only till everything opens evenly at the same amount of throttle input, or you are going to continue have the off idle stutters
_________________
Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval

[DerrickfromNC1]

I've chked and double chked and the syn appears to be on the money. I've had numerous dual Webber and dell setups on past engines so I pretty sure it's not a carb syn issue.

[stanovich]

are the intake runners stock or ported, how about a vacuum gauge to let you know what is going on , when you pop open the throttle. what type of fuel pump or fuel line size. correct me if im wrong , fuel is pulled in by vacuum so you could get a stall and then as vac picks back up everything is fine.

[DerrickfromNC1]

[DerrickfromNC1]

Acel nozzles fine now still off idle bog. Getting ready to try a 2nd 009 I have in the parts bin if that fails can I install these:

http://www.cbperformance.com/ProductDetails.asp?ProductCode=2040

under the carbs to run vac to a SVDA dizzy? I already have some that came with a digital Magnaspark that I purchased to be installed on a 2332 in my car.

[DerrickfromNC1]

Tried a second older 009 I had in my parts bin & it was only marginally better....still an initial bog.
I next tried a loaned SVDA T'ed to both vac ports on my 40idfs.....a little better but still there. I then tested the vac advance and found that the advance mech starts moving with 4"HG and is fully advanced at 9". My idfs are only pulling about 5"....not nearly enough to fully activate the advance mech.

Here are my options as I see them:
a. Get the anti pulse valve($40) & hope it doubles the vac pull to about 10"
b. Do what many do and install a Bosch 010($200 or more) and be done with it
c. Get a CB Magnaspark($160) which means I will also need to install a late
model alternator type fuel pump to clear the Magnaspark.
d. Any more options???