LT intake manifold modification for distributor

Well I have been rounding up components to modify some LT1/4 manifolds for a distributor in the normal location instead of the front mounted Opti-spark---I never had any problems with the optis (exept for the rpm limit) but I want to remove the opti from the front of my wife's 33 coupe for more front room for a low mounted alternator and I have 3 or 4 manifold around here so I'll just do the batch of them at the same time, polish/powder coat etc.

Will work on getting some pics of the process and progress-----------

yep i was asked to do one some time ago . should go good with the mill set up run them all threw the set up

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Originally Posted by jerry clayton

Will work on getting some pics of the process and progress-----------

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Thanks Jerry! I don't "play" with sbc so I'm curious as to what you're doing.. Haven't heard of this before now..

So help me out here, Jerry. The OptiSpark is shaft driven off of the front of the cam, with recessed holes that fit over the cam retaining bolts and a keyway slot that picks up the cam gear key for precise alignment, right? So you're swapping out the cam, using one from a non-92-96 SBC which has a distributor gear on the back of the cam, then machining an intake to accept a cam gear driven distributor? I'm not following how that's all going to work...

Roger----I know the distributor is on the wrong end of the engine for you-------

The cam has the gear on the back to drive the oil pump and uses a gear/shaft adapter thats in the same position as a normal sbc distributor--there just isn;t a hole in the manifold for it---got to machine away some egr bosses and fill and weld in a mounting hole for the dist shaft and holddown ---I will get a couple pics today--------

http://<a href="http://s1292.photobu...ps59c8a796.jpg[/IMG]

been trying some photobucket and seems like its time to go get a beer or two

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Originally Posted by jerry clayton

http://<a href="http://s1292.photobu...ps59c8a796.jpg[/IMG]

been trying some photobucket and seems like its time to go get a beer or two

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Jerry,
I think you're likely making it harder than needed. In photobucket open the folder/library where the pictures are that you want to post. There will be a bunch of them in small boxes, maybe 1.5" square, and each of those frames has an eight sided star in the upper right corner when your cursor is on that picture. Move your mouse over that "star" and a menu list drops down. Move your mouse within that box to "Get Links", and then from the links put the cursor on "Image Code" and click the mouse. You'll see "Copied" appear. That image is now on your clipboard.

In CHR, go to your new message, and in the text box simply right click, hit "Paste" and the image file is pasted into your message. You don't have to do anything else, other than add any descriptive text that you want, either above or below the image code that you see. For sure DO NOT click the "Insert Image" Icon, or you'll get extra crap that's not needed, and that will not work. Try that and see how it works.

[URL=http://s1292.photobucket.com/user/jerryclayton/media/008_zpsacfae25c.jpg.html][IMG]http://i1292.photobucket.com/albums/b568/jerryclayton/008_zpsacfae25

http://i1292.photobucket.com/albums/...psacfae25c.jpg




this is a view of the back ends of both types of manifolds and a oil pump drive gear for an LT1 and a distributor

http://i1292.photobucket.com/albums/...psa7778db2.jpg

compare the distributor and the LT oil pump drive gear

http://i1292.photobucket.com/albums/...ps2dea8076.jpg

Back of the manifold with rough cut off of the egr stuff and view of the drilled pilot hole

http://i1292.photobucket.com/albums/...ps7fc9fcd3.jpg

with the drill poking thru


http://i1292.photobucket.com/albums/...ps9a5934eb.jpg


from the bottom side

http://i1292.photobucket.com/albums/...psa6338478.jpg

View of drill guided thru bushings in oil pump housing and main cap

http://i1292.photobucket.com/albums/...psfef195d7.jpg

what the drive piece looks like and a view of the modified fixture one in position

http://i1292.photobucket.com/albums/...psfb74b054.jpg

http://i1292.photobucket.com/albums/...ps59c8a796.jpg

and with the drill

Thanks Roger---I might get the hang of this bucket deal yet

To answer about just using a 92 block(pre LT1)---the LT engines have reverse cooling in where the coolant is pumped thru the heads first and then returns thru the block--they were able to run higher compression ratios and on about any gas you put in the tank all the time with good economy and broad torque/horsepower---
I never had any problems with the opti spark, I just want to move it so I can mount the alternator and A/C down low on the front of engine but the spark terminals of the opti are in the way----------------

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Originally Posted by jerry clayton

Thanks Roger---I might get the hang of this bucket deal yet

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You bet! And you can put up to 35 images in one post, spacing them as you wish with text in between the image files to tell the story. They work pretty neat!

Thanks for the pics and explanation Jerry! Looks like you're on your way with the photobucket deal... 8-)

Doesn't hardly seem like this has been over a year---winters are too short--most be global warming

That is a neat mod! Can you show us the finished manifold and maybe the dist mounting piece you weld in?

I'd like to see the finished deal too. There are a lot of LT guys that would probably love to have this mod.

Just curious. Did the LT1 manifold survive the surgery???? Street rod engineering at it's best!

WoW-going on 2 years---------


Did 3 manifolds back when these pics were done-


Just last week end a guy brought in another one for me to do so after I finish up re paneling my garage door it'll be cleaning core and making chips and welding-I'll try to get pics of the finished job and some of the different dist that have been used---not a lot of room for the big cap hei like thingies

The multiple chamber openings you cut into made me wonder if this was doable. Not sure what each was other than the egr, but thought this might take multiple patch pieces to make it work. If you were able to get a clean finished look, this would be quite an impressive mod to say the least.

Or, for about $300 - http://www.summitracing.com/parts/NAL-24502592/ Seems to me that the machine shop costs would be equal to or more, but I may be wrong. Of course when you're doing the machining it's a different story, as your rates for your own work can be zilch.

Duece4------I usually get a clean, finished look to any mods I do on my stuff


Roger-------the manifold is a way to go if a person wants to just put a carb on an LT1 for some other era car, but the costs are a lot higher than the $300 ------you will need a carb, air cleaner, fuel pump and lines, regulator,etc plus of course the complete ignition system-a person going that route will be spending maybe as much as $2500?----


Now , not to say that he won't be spending $$ on this conversion, but it does allow the keeping of an excellent EFI system and basicly just getting rid of the opti. I myself never had any issues with an Opti but I want to move it out to get rid off the wires down there so I can mount the alt and a/c close to crank area-- However, on my wifes 33 I did move the engine back toward cowl for more room behind radiator and its tight where the dist goes----but the driveshaft is shorter!!!!!!!!!!!!!!!!

I have mounted both the a/c compressor and alternator down low on my engine. I can see where the opti spark dist would interfere with this. I don't think I could have found enough room for the LT1's extra length over the short water pump setup, but for some builds that require the low mounting, the reverse flow and TPI might have been worth all the manifold fab work. Going from a manifold shown in Jerry's post to a functional manifold is quite a leap to make.

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Originally Posted by jerry clayton

....Now , not to say that he won't be spending $$ on this conversion, but it does allow the keeping of an excellent EFI system and basicly just getting rid of the opti. I myself never had any issues with an Opti but I want to move it out to get rid off the wires down there so I can mount the alt and a/c close to crank area-- However, on my wifes 33 I did move the engine back toward cowl for more room behind radiator and its tight where the dist goes----but the driveshaft is shorter!!!!!!!!!!!!!!!!

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I'm not familiar with the opti-spark distributor system, but as I understand it inputs to the PCM for crank position (laser through disc w/360 tiny slots), and the PCM then triggers the output to the coil based on the spark map that's in the PCM, and also triggers the injector pulses based on this crank position input, right? When you make this change you'll use an electronic distributor, but what do you do for the crank position sensor? Sounds like a neat modification, and I expect I can find out about it on the hot chevy sites with a little Google mining but it's lots easier to ask the guy who's done it before.

Roger-basicly this just moves the rotor/cap part to the rear of manifold--with the later years LT there is a more modern sensor in the timing cover so that and the fact that the 1996 and up ( on all vehicles OB2) are much more advanced than the early ones-----I think that most of the problems people had with opti was self induced-washing engine with high pressure washer, etc-also there was a vent system tied into the intake manifold and air cleaner so clean dry air would circulate but when pepes put fresh cold air intakes, etc , etc they lost the oem system of the vent-then the heat/cool cycles probably created a vapor/condensation issue-------My distributor will just be a rotor/cap with the coil, timing functions still done by the PCM.
However I am doing one for a guy that is taking off a coil/plug like the new LS engines as it didn't meet expectations and he will be doing his with a FAST XT? instead of the oem-(oem is limited to 6 or 7000 rpm)


Duece, if you haven't changed the intake or exhaust its not a hot rod??????????
I believe that the LT water pump being driven from the cam is more compact than the older engines by eliminating another pulley. the issue with my install into my wifes 33 is that now that we want to add a/c, we need something on each side of the crank and to lower them (alt, a/c) enough to clear the wire terminals of the opti gets down low and close to steering stuff. I have thought abought driving alt off tail shaft but if we run air will need more amps/mile and in slow moving traffic probably wouldn't keep up. If you have looked at front of LT1 engines, keep in mind that there are different length lower pulley/dampners from various installs-vet, Camaro/firebird/buick/impala/etc

Looks like there are several LT1 intake mods going out there. Opti Spark to dist with several paths taken from plugging holes to major milling of material and adding plate along with dist mount shim being welded in. Others are modifying LT1 intake to fit SBC first gen. Wow. There are a few photos of modded intakes out there. Some are very well done; others not so much for looks but probably work fine. Neat stuff for sure!

So if I understand what you're saying, you're leaving the low voltage part of the optispark (PCM inputs) in place on the front, eliminating the cap & rotor, and installing a stand alone dizzy in the back for the HV function? I agree, most of the opti problems seemed to be self induced by power washing....

Roger-----there are several ways of triggering the ignition , it might be just with a regular dist and coil with the advance curve set from weights /springs or up to being triggered by a system like the Fast stuff where actually the spark trigger is set at quite an advance setting( 50-60*) and the system retards the spark event to the setting programmed -------The minimum required is a crank position sensor which can be a simple pick up at the dampner or flywheel. Some of ( probably all) of the latest systems have reluctor wheels on one end of the crank ( most rear counterweight) of around 50-60 notches with one unique pattern to differentiate # 1 tdc-------
On Robins car I intend to use the trigger up front and use the OB2 PCM with just CAT deletes and maybe speed density-probably what ever Corey wants to tune it to----Did I tell you that he is now working at Victor/Dana research center?


Duece-------putting one of these manifolds on the earlier engines allows a well designed EFI to be adapted to early engine however there is no thermostat housing at the front and you have to either weld some fitting bosses in place or use a fabricated piece on the front of the head as these are designed for a reverse flow coolant routing on the LTs.


And as far the appearance of the fab work-------there is a thin line to walk-------one goal is so its not ugly , another well fitted and nice professional looking work, and another---invisible to modification but maybe a slight trace of something a little different from anything the viewer has seen stock leading him to believe somethings been done----
For me-------it gets more difficult to live up to the bar that I have historily been compared to every year as I get older------but it will be good enough that I won't get docked any points at any show I might enter and may or not be pointed out in any Magazine article----

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Originally Posted by jerry clayton

Roger-----there are several ways of triggering the ignition , it might be just with a regular dist and coil with the advance curve set from weights /springs or up to being triggered by a system like the Fast stuff where actually the spark trigger is set at quite an advance setting( 50-60*) and the system retards the spark event to the setting programmed -------The minimum required is a crank position sensor which can be a simple pick up at the dampner or flywheel. Some of ( probably all) of the latest systems have reluctor wheels on one end of the crank ( most rear counterweight) of around 50-60 notches with one unique pattern to differentiate # 1 tdc-------
On Robins car I intend to use the trigger up front and use the OB2 PCM with just CAT deletes and maybe speed density-probably what ever Corey wants to tune it to----Did I tell you that he is now working at Victor/Dana research center?

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Thanks Jerry, I'm aware that there are lots of options for triggering the ignition, and my question was more to what's your plan, since you seemed to be glossing over that key point, but were saying that you're retaining the OEM EFI. As they say, the devil's in the details, and it sounds like the answer is that you're taking care of the distributor move and then looking to Corey for the details on what he'll need to make it work. If only we all had that Corey resource available!;)

Roger sorry if misleading but I've been discusting different options for the reason to do this-
On Robins car, it will stay pretty much stock except will have headers I'll build and no cats-------so delete cats, and also since its a 96 OB2 system and they run real good, I may only do away with a couple features and go speed density instead of the mass air flow which however works real good-----------In our family we've had 2 of these cars, I had a 92 vet and Corey had 94 Camaro-both got totaled with 2 miles of home-------


they ran good, torque, any gas you put in them, good milage, etc-------


However, the units that I do for someone else can do whatever they want they just have one common trait-gets rid of opti----------I'm moving mine so I can complete my bracket package for the low mount alternator and a/c-water pump is cam driven so no belt/pulley on it-cleans up the radiator to block area---and using the Tauras /Lincoln elect fan-------

To the top for answer to todays LT1 posts

Quote:

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Originally Posted by jerry clayton

Duece4------I usually get a clean, finished look to any mods I do on my stuff


Roger-------the manifold is a way to go if a person wants to just put a carb on an LT1 for some other era car, but the costs are a lot higher than the $300 ------you will need a carb, air cleaner, fuel pump and lines, regulator,etc plus of course the complete ignition system-a person going that route will be spending maybe as much as $2500?----


Now , not to say that he won't be spending $$ on this conversion, but it does allow the keeping of an excellent EFI system and basicly just getting rid of the opti. I myself never had any issues with an Opti but I want to move it out to get rid off the wires down there so I can mount the alt and a/c close to crank area-- However, on my wifes 33 I did move the engine back toward cowl for more room behind radiator and its tight where the dist goes----but the driveshaft is shorter!!!!!!!!!!!!!!!!

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A dumb question for you Jerry, could one work a crank trigger system onto an LT engine? I love their simplicity and easy of adjustment on the timing! Just curious and wondering if you have done one?

I thought I might throw my 2 cents into this conversation. I always read gen 2 LT1 stuff when posted because I own three of them. Two run('94 Z28 Camaro, '97 SS Camaro)and the third is going into to a project truck('57 Chevy) if I ever find the time to finish it.
As far as the optispark distributor, On the '94 I've changed the distributor twice in 110k miles. It has the older non-vented design which crap out at roughly every 50k miles. The last one I put in was a newer design MSD that includes venting and has gone about 10k miles trouble free. I also have an MSD unit on the '97 that is trouble free.
With regard to Dave's question, I have been considering going to a crank triggered coil on plug system in the '97. Not because the optispark is problematic but because it would allow me to use a PCM that is way more advanced than the original '97 PCM along with the precise spark energy and accuracy of coil on plug.
I know a engine tuner that told me the LT1 PCM's are dinosaurs compared to the newer LS PCM's in the sense of being smarter and faster. Makes tuning a big cammed LT1 possible. Here's a link to a setup I'm considering buying from what seems to be a very innovative company. A plug and play setup that can be done in a day.
https://www.torqhead.com/how-it-works.html
Nolan

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Originally Posted by JOATMON

I thought I might throw my 2 cents into this conversation. I always read gen 2 LT1 stuff when posted because I own three of them. Two run('94 Z28 Camaro, '97 SS Camaro)and the third is going into to a project truck('57 Chevy) if I ever find the time to finish it.
As far as the optispark distributor, On the '94 I've changed the distributor twice in 110k miles. It has the older non-vented design which crap out at roughly every 50k miles. The last one I put in was a newer design MSD that includes venting and has gone about 10k miles trouble free. I also have an MSD unit on the '97 that is trouble free.
With regard to Dave's question, I have been considering going to a crank triggered coil on plug system in the '97. Not because the optispark is problematic but because it would allow me to use a PCM that is way more advanced than the original '97 PCM along with the precise spark energy and accuracy of coil on plug.
I know a engine tuner that told me the LT1 PCM's are dinosaurs compared to the newer LS PCM's in the sense of being smarter and faster. Makes tuning a big cammed LT1 possible. Here's a link to a setup I'm considering buying from what seems to be a very innovative company. A plug and play setup that can be done in a day.
https://www.torqhead.com/how-it-works.html
Nolan

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Thanks for the link, great information there, looks like a fine product!