over boring questions

J

jester1341

topless and blown
Mar 30, 2005
319
0
16
39
Western Maryland
i've been out of the secne foe a bit but never ditched my baby['87T targa].....i did neglect her thoug:nono:

anyway.... i am going to be rebuilding the engine and am not going to ask all the typical questions[that i prob will later on] but i have some questions that i didn't really find answers too, but i may not be quite sure what i'm looking for either....

first off i am not sure why the car stopped running....never got around to it.....not enough time or money. the engine will be removed and stripped. i plan to have it prof cleaned and the head decked....but i was wondering about over boring.

i have never had a block bored out, and do not know what to expect, any special needs before during or after. one question i have is how big should i go with the bore?? i have an '87 with the stock block and internals, swapped out for a 3angle valve ground head and new stock gasket with ARP bolts.

so more or less the internals are all stock. i want a fast car, but not a car i feel should be trailered to the strip. i was running about 11-13lbs on my DDP, minimal shims, 2" IC piping, and12"x24"x3" FMIC....it was mean and loud and that is exactlly what i want again, but just a little more balls!

how big is gonna be 'too big' for me i want to run a CT-26, but may have it upgraded.

anyway, i'm kinda getting off my point....boring os to get a more optimal bore and stroke right? what is gonna give me a good medium??

any advice is helpful thanks,
john
 
pln

pln

Get the gate!
Apr 10, 2007
107
0
0
eskilstuna.SWEDEN
bore minimum. save as much material as possible. If something goes wrong i the future you may need to drill again.
drill a new cooling channal in the head, behind six:th pison. throw out EGR and put a big screw in the hole between cylinder 6 and the EGR cooling chamber, to get more efficiant cooling in the head.
use loctight black silicon for the oilpan and lots of it.
-check the straightness of your head not only underneth but ontop aswell and diagonal with a steel ruler. sometimes the hole head twists.
 
WhtMa71

WhtMa71

D0 W3RK
Apr 24, 2007
1,813
0
36
Macon, GA
pln;1184618 said:
throw out EGR and put a big screw in the hole between cylinder 6 and the EGR cooling chamber, to get more efficiant cooling in the head.
Click to expand...

Bad advice.

Like already stated..bore the least you can. Usually that would be .020 or .5mm.
Take the block to the machinist first, he'll tell you how much needs to be removed, then you can buy the correct pistons but make sure he has the pistons in his hands before he bores the block so he can get the correct piston-wall clearance. Get the head and the block resurfaced as smooth as possible for a MHG and use arp studs.

**Oh yea and this is very important!!!**
Install and torque the timing belt tensioner to spec(36ft/lbs if I remember correctly) before the block is bored/honed!!
 
jdub

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
1
38
Valley of the Sun
pln;1184618 said:
throw out EGR and put a big screw in the hole between cylinder 6 and the EGR cooling chamber, to get more efficiant cooling in the head.
Click to expand...


Very bad advice if you're planning on using a USDM ECU...that is unless you want to risk detonating your motor. And, it doesn't do squat to help keep the head cool...it's the opposite. The EGR keeps cylinder temps down.
 
gaboonviper85

gaboonviper85

Supramania Contributor
Jan 13, 2008
3,236
0
0
38
Northeast Philly
pln;1184618 said:
bore minimum. save as much material as possible. If something goes wrong i the future you may need to drill again.
drill a new cooling channal in the head, behind six:th pison. throw out EGR and put a big screw in the hole between cylinder 6 and the EGR cooling chamber, to get more efficiant cooling in the head.
use loctight black silicon for the oilpan and lots of it.
-check the straightness of your head not only underneth but ontop aswell and diagonal with a steel ruler. sometimes the hole head twists.
Click to expand...

this post should be deleted..
 
R

rawmk3

New Member
Jul 5, 2008
170
0
0
IL
gaboonviper85;1184700 said:
this post should be deleted..
Click to expand...

not true. its true to check the head for straitness, because a warped head before that was decked could still have cam journals that arent aligned correctly. But still have a flat mating surface on the bottom. Not good for that to happen. But the EGR removal is not good for a daily driven car.

IJ what happened there. It looked like a BHG. Is the auto tensioner install the same as using a tq plate on these, or are u guys referring to the machining of the timing cover to match the block? Cause im confused.
 
I

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
0
0
61
I come from a land down under
If the Cam Tensioner is over tightened it pulls the bore and the rings can't touch the cylinder wall.

Ditto when the block is bored as at 36ft/lbs I measured half a thou deflection so if you have a block bored without it in place the bore will be half a thou out of round when it's installed.

If you look at the pic the brown area has never been touched by the rings in 20,000 KM's and the motor had blowby from day 1.
 
hvyman

hvyman

Dang Dude! No Way Man.
Staff member
Apr 17, 2007
12,568
1
0
Fullerton,CA
and it only takes a small bead of fipg for the oil pan. gobs of it is just going to smush out on the sides.
 
jdub

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
1
38
Valley of the Sun
I use Permatex "The Right Stuff"...I've never had a pan leak with it. The TSRM says use FIPG and not a gasket. And, Hvyman is right...you don't need a huge bead, just enough to get a very small amount pushed out the side when the pan is torqued down so you can see it.
 
J

jester1341

topless and blown
Mar 30, 2005
319
0
16
39
Western Maryland
wow 15 responces, and some of them are even about over boring...haha j/k

good advice though, i would have never even thought about the cam tensioner...

thanks fellas

john
 
Zumtizzle

Zumtizzle

Can't Wait to Be King.
Oct 21, 2006
2,825
0
36
Sac-Town, NorCal
IJ.;1185891 said:
3bond 1207b, best RTV I've used in 30+ years of playing cars ;)
Click to expand...

In America

You can get it for 20 bux at any Suzuki Motor Bike Dealership.

http://www.suzukicycles.com/accesso...essoryId=802d9c5d-5688-4c4f-a61a-e027561e2a1f

I've read the data sheets of lots of sealants, this is no joke. It withstands high three digit temps, and low four digit pressures.

And wow, the forum is working quite efficiently. (talking about people chiming in.) :)

And going .20" over or .5 MM over is what i'd do op. :)

NPR (Fleabay) for your goals will be fine. :)

http://www.supramania.com/forums/showthread.php?t=5631
^read through that.
 
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