hey guys,

i recently removed all the bolts on my intake plenum and runners to get to my EGR not realizing a few were different sizes!

does anyone have a layout of which size bolts go where? (assuming longer ones bolt runners to the manifold and shorter bolt the plenum to the runners but not sure which holes require a longer or shorter bolt)

thanks in advance!

 

Pictured above is the typical set up for a 1986-89 MAF based system. Speed density is similar. (A) Intake manifold. (B) EGR valve (C) EGR temp switch (maf only) (D) PCV fitting, to the left is orifice for cold start injector (maf only) (E) Thermostat housing neck and bolts (F) Bolts needed for top plenum and runners- 13- M8x1.25x30mm, 2- M8x1.25x40mm, 4- M8x1.25x50mm, 1- M8x1.25x30mm throttle bracket stud, 20 total, these use a T40 Torx head bit, NOTE these are metric. (G) Fuel rail typical for a "F" body, maf system, fuel lines for Corvette is on opposite side. Look at picture, as this is a complete system (H) cold start injector and fuel tube (maf only) (J) Fuel injectors-8 total (K) Intake runners, speed density will not have the cold start opening (L). (M) Intake air sensor (P) Intake plenum, with throttle body, be sure to get complete throttle body with no missing upper and lower cover plates, bottom plate has provisions for IAC and coolant tubes. (Q) Throttle bracket and bolts (R) Vacuum fittings for fuel regulator, heater control and brake booster, speed density will have a fitting for MAP sensor and mounting boss.[/QUOTE]

 

TY! the diagrams are very helpful and i see that the bolts include:

13- M8x1.25x30mm,
2- M8x1.25x40mm,
4- M8x1.25x50mm,

however i am still not sure which length bolts should go where. e.g. where do i put the two 40mm ones and the four 50mm? assuming base of the runners but not sure which holes!

 

IIRC the 2 50mm go through from the backside of the intake into the runners the picture above with the intake shown and the red lines . 40mm goes in the runner bottom side holes. because the only other longer ones are for the throttlebody but I think those are 65mm.

 

i see thank you, i will get out there and correct this!

thanks all!

 

I received my 89 iroc tpi unit in pieces can someone please show where each lower intake runner bolt goes......there are different sizes...thanks

 

see above photos

 

On more than one occasion I've held the runner in my hands and just placed the bolts in to see how far they stick out the other side, then moved them around as necessary. .....I'm pretty good at it now though, sheesh......pulled em off TOO many times!!!!!

 

TunedPerformance had the (2x)40s and (4x)50s reversed...

40mm (middle length) are the inside-out bolts. These are the only ones that screw into the runners. These are indicated by the red lines in post #2, middle picture.
50mm (long) - one for each runner pair. Between the tubes into the lower manifold.
30mm thread with stud - This is driver's side, middle, upper bolt. If you have everything, there is a plastic sleeve with a clip-arm to hold the cables for throttle, cruise, and possibly trans.
30mm bolts everywhere else.

And Abubuca x2... stick the bolts through the runner holes and figure out which goes where.

 

Thanks......I have one bolt that is a different length than the rest about a 1/4 inch longer than the 30mm...a little shorter than the "inside out" bolts...I guess I can shim it with washers for now...

 

x2 this helps
Nice diagram man brings back memories I hated working on those lol.

 

I coulda used this info when I did my job....ended up grinding one down a smidge...kinda like the three stooges putting a puzzle together..they would just cut pieces to fit!...

 

And I will be using this info on my first TPI build..thanks.

Rich

 

Does anyone know where to buy these crappy Torx bolts in a set? Half of mine are stripped out. I thought about just going to the local hardware but those probably aren't hardened properly. I'd rather buy the right ones.

 

Most cases it's easiest to get a kit of stainless bolts. Just make sure you use antiseize and NOT to torque them to factory specs, use stainless m8 torque spec. Significantly lower but hold just fine. They will tear up the intake if you go to stock spec. These guys have been making kits for years. https://alloyboltz.com/product/gm-30...F3SgnTeAnoj1e0

 

"Just make sure you use antiseize and NOT to torque them to factory specs, use stainless m8 torque spec. Significantly lower but hold just fine. They will tear up the intake if you go to stock spec."

That is an excellent point.

 

Anybody have an EGR valve for an 85 TPI WS6 available? Would appreciate all answers!!