OK, its time for exteme trivia here, but a question I really need answered so I don't have to run all over town. I am adapting an LT1 Trottle body to my TPI motor. The Throttle positione sensor is different so I had to buy an LT1 TPS. The bolts of the TPI stock TB are too long and I cant find any shorte bolts that fit in there. They are apparently a wierd size or thread. Who know what size and thread the TPS mounting bolts are on a stock L98 TB?

help?

 

I'm really not sure, but the best advice i have for ya would be to go to a dealer and get a throttle body bolt kit for an lt1. it comes with the tb top plate bolts, bottom iac housing and coolant housing bolts, and the tps sensor bolts. oh, and atleast they're expensive too. i did this for my tpi and dished out 25$ for these stupid little screws. Thats probably your best bet, unless you bring the tb to a hardware store and go through all the little bolts to find the ones yo need. just and idea.

 

Ive been to 2 hardware stores and two auto parts stores. I also called a GM dealer and yeah they said they would sell me a fastener kit for $23 with a bunch of stuff I dont need. The problem with that is I would have to buy the LT1 kit to get the right length bolts,then other stuff might not fit. Also they would have to order it of course they dont have it in stock. I guess the next steip is to pull out the TB and go to a special bolt fastener store. Thats what I meant by running all over town. Another option would be to drill out the holes then retap them with the next common size you can get at hardware stores. I could do that at my local hardware store and I'd be saving trouble in the future if I needed more bolts the same size. Hey! I just solved my problem. Should be planty of aluminum around that area

 

Do you still have the old ones? Why not just cut em down so they arnt that long anymore?

 

Sure its not just M6?

Maybe 4 - Its not a "special thread" I can almost assure you.

You bought a Lt1 TPS, why not use the screws that Came with it ?

 

Didnt get any bolts with the new one. I could maybe cut the old ones down, but I think it would mess up the threads

 

I forgot completely about cutting the screws. I've done it hundreds of times, cause i was in similar situations. what i did was when i cut the screw shorter, i made sure the end was as flat as possible, as in, its surface would be 90 degrees to the length of the screw. then i grind the "corners" (if you look at it like a rectangle) around the cut end to sort of make the threads blend into the end. If you look at it before cutting, i think you'll know what i mean. this is so the screw can sort of "screw its self" into the threads without crossing them. If not, it can just be like any other road block when doing a mod. just a suggestion. good luck.

 

I cut mine down thats whay I said it. If you dont fell comffy doing it send em my way and Ill do it and send em back to ya.

Let me look around I might still have my cut ones also.

 

I brought the TB with me to work today and Im going to take it down to a bolt place near here. I could cut them down but there still is another problems. The TB is missing one of the two bolts that hold the round TB blades in place. The other one will certainly hold the blade all right but this leaves a bolts sized hole in the TB blade, causing the car to idle too high. This hole appears to be the same size/thread as the other. Ideally I would like to get three bolts that are the right size and length, hopefully I can find them at the bolt place. If not its cuttings down the two tps bolts, and looking for a self tapping bolt and loctiting it into the tb blade hole

Thanks to the people that replied seriously to this thread. I appreciate this site a lot, its been very helpful to me.

 

Larry, Another idea, look in the yellow pages under fastners and call to see if they help match up bolts. Most companies will help, Dorman, Kar Products, Bowman are some that come to mind. Just my two pennies, Dave.

 

Well thats what I plan to do. When I say I going to a bolt place I mean a store that I found in the yellow pages under bolts/fasteners. I assume they have every kink of bolt and nut known to man, Ive got the TB with me at work and there are several of these places near where I work. Thanks

 

In the interim, you could make some spacers from short sections of steel brake tubing (flared end toward the TPS to minimize localized stress).

Incidentally, the screws are M4.5-0.7 x 12. The O.E.M. screws are a T-20 cheese head with a Sems washer and short lead-in shank on the starting end. You don't need the lead-in, nor the specific head style, just the correct thread and length. You're going to have a bitch of a time finding them, however, since some mutherfrackin' genius at Rochester decided to use the proprietary M4.5 instead of either M4.0 or M5 threads. If it were mine, I'd get M5-0.7 x 10 and a tap (or 10-32), and fix their vertically-fornicated problem forever.

Either way, make sure you apply an anti seize compound to the threads before installing the screws, or you'll have the same issue as many others (do a search for TPS + SCREW + BROKEN).

 

Bort,

Unfortunately, it isn't a very common thread. Fastenal, Service Supply, and most other suppliers don't even list the thread, and taps for it are just as hard to come by.

You could take your T-20 bit to the bone yard and find an older cop car, Caprice, 'F' car, etc., and get what you need for a lot less than $23.

 

Well I thought I was going crazy here, not finding that bolt, but I forgot about the genuises at GM. Why make it so you can buy a 50Cent piece at a hardware store when you can charge $20 and have to wait a week to get in the special order.? Anyway, went to a fastener place at lunch and no dice so I guess Im going to go the tap out to either m5 or 10/32. I read this guys thread


https://www.thirdgen.org/techbb2/sho...s+screw+broken

after doing the search and got a lot of good info. I do have the additional problem or a broken bolt in the top hole so Im going to drill both out with the #21 bit, then tap to 10/32.
I really appreciate you help on this, I heard you were the man on this site and Id have to agree. thanks again


:hail:

 

Two other quick questions concerning adapting this LT1 TB to the TPI motor

1. the throttle cable is too short due to the slightly moved forward position of the conector on the TB. I have been wiring it up with come little cable but it keeps on slipping and looks like $hit anyway. I ordered a Lokar throttel cable on summit (41" i believe) that is for "early and late model GM tuned Port injection cars". Hopefully this will be longer and is to be adjusted and will fit. The connectors in the picture look wierd though. Will this bolt right on and work do you think.

2. One of the two small bolts holding one TB plate to the center shaft is missing, creating a vaccum leak. It is apparently a wierd size too, Can I just silicone it. Will it get too hot and with the air flow get sucked into the engine?. Might it be better to get a self tapping bolt and lock tight it in there?

thanks

btw, the car runs great, I ran a 8.68 in the 1/8mile last weekend with my jury rigged setup (wired up cable and spacers on the tps bolts), best I ever ran

 

Lary,
Did you order the Lokar bracket also or just the cable?
I have the bracket, tranny cable and throttle cable.
They are pleanty long enough and have lots of adjustment. I can take a good pic of the cable ends and bracket to show you.

I also broke a top D plate bolt befor and just used some silicon to fit that problem.(temp soution that works)

 

shoot, I just ordered the cable, I dont guess it will work with the stock bracket? then Ive got to order teh tranny cable and cruise control cable too? jeez now we are getting expensive
I would love to see the pic
thanks

 

:shrug:

Find a nut that will fit on the threads... put nut on bolt past the part where ya wanna cut. Cut bolt as flat as possible (can use the side of the nut as a guide). Remove the nut. If the threads were jacked when cutting, the nut wil usually straighten them out as it comes off.

Dat's it!

 

Vader, YOU ARE THE MAN !!!:hail: :hail: :hail: Never to old to learn, Dave

 

This is the only old pic I can find of em. Hope this Helps.

 

Well obviously the bracket is completely different than the OEM one. So I am right that I would have to buy the bracket and a tranny cable from Lokar right? I noticed you dont have any cruise control connected. I was thinking of just disconnecting mine since I never use it. Shoot, that means Ive got to spend probably another $50 on bracke and tranny cable. Add that to the $40 for the throttle cable, $20 for the LT1 TPS, and $190 for the 52mm TB on ebay, and I could have bought a brandt new Holley 52mm TB with nothing to adapt. Im going to have to stay away from ebay, I cant afford all the money Im saving on there, LOL.

 

Just checked Summit, make that $50 for the tranny cable and $26 for the bracket. I guess it will be a nicer setup though. Is there any problem to just remove all that cruise control stuff. I don't really need it at the drag strip, ha

 

I belive you can get a 3post one for cruise also. I didnt since I janked mine out anyways.

The cables/bracket are well worth the $$ That look 100x better then the stock crap.

 

Yeah I guess so. I might try to make the throttle cable work with the old bracket until I can afford the other. Do you happen to know the part number for the bracket? Look on this link and see if this looks right

http://store.summitracing.com/defaul...rchType%3DBoth

the part I think is called "bracket aluminum double stud". the part number ends with TP which I assume is for TPI as the tranny and throttle cable parte numbers for TPI end with TP as well. There is single stud, double stud, and triple stud, Im assuming for one, two or three cables (throttel, tranny and Cruise right?). I was going to go with the double and get rid of cruise like you did.

I guess I should call summit and talk to some one to be sure that is right, I just hate waiting on the phone then talking to someone who oftentimes knows less than me

 

LOK-TCB40TP2

I think thats It.

Call Summit and ask for BRANDON.
I forget the ext. #'s 5128 maybe.

He's one of the guys who posts on 3rdGen. His real name is Jeremy. He's not just another of the morons that work there.

 

i'm bringingt this one back, Larry , or anybody who else did this. was it worth it and how much of a PITA was it. other than the screw problem. cause it sounds like you spend around $100+ in parts alone to get it to fit

 

Im glad you asked really because this was a major learning experience. The bolt problem wasnt´that bad in the end. The best thing to do is just drill em out and tap em the next common size. The throttle cable was a major disaster. I put on the lokar throttle cable, bracket and kickdown cable. The throttle cable was a pain because you cant use the little plastic piece that holds the stock cable housing in the firewall. The plastic one just snaps into place in the hole. So I improvised using some large washers. The main problem then is that the cable is at an angle from the firewall to the throttle pedal because the washers don´t hold the cable at the proper angle when it passed through the firewall like the stock plastic piece did. YOu feel a significand resistance on the throttle pedal because the cable is rubbin on the side of the housing. In time it might even cause it to wear and break

Secondly, and really the biggy problem, is the TV cable. You cant use the old one because it doesnt fit in the bracket. THe new one is kind of a bitch to install, at least where it connects to the TV in the transmission, but I got it in. then the real problems started. I never, never, could get the TV cable adjusted right. I finally took it to a tranny guy and he pulled of the tranny pan to be able to look at the TV lever when pushhing on the accelerator to make sure it was extended at WOT. After setting it this way, then pushing the accelerator up and down a few times, it was out of adjustment again. He concluded that the cable was stretching, and suggested I jerk the whol frickin thing off and replace it with the stock stuff.

so finally I sold the LT1 TB, got a proper 52mm one, sold the Lokar crud for 25% of what I paid for it, and it worked good. The TV cable adjustment apparently is very critical on thes cars and it is easy to do with the stock bracket-ratchet deal

Finally, shortly after that, my tranny went, the 2 to 3 shift is now completely gone, like putting it into nuetral. I am positive that at least part of that was driving it, and even racing at the strip with the TV cable out of adjustment.

So starting with the TPS bolts, and ending up with a trashed transimission, I would recommend, DONT DO IT!!!!

Ive got a th350 ready to put on, no more tv cable adjustment for me

:lala:

 

I did not read the entire thread. So if I'm late with the correct answer, give me a back.

The stock TB bolts on my '87 IROCZ are M8x1.25mm, and are 70mm in length. It is definately a metric bolt.

M8x1.25mm