BlackDuk98

iTrader: (34)

:this regards to a '98 LS1:

Well, I purchased a TCI 399753 flexplate to use an aftermarket th400 torque converter. The side of the flexplate that goes against the crank would have the head of the torque converter bolts sticking out. The TCI plate has these points recessed. If I use a washer under the head of the bolt, the bolt will stick out .300 above the flexplate. I don't think that I need a washer under the head, but I will need one under the nut which is on the top of the TC pads. If I decide not to use a washer under the head of the bolt, the head will only stick up .200.

I originally purchased a set of ARP 7/16-20 torque converter bolts, but they were a half an inch too short. So I purchased some grade 8 7/16-20 bolts from the hardware store to use. The ARP's only have 1 washer per bolt to go under the nut. This is the reason that I am thinking that I don't need one under the head of the bolt. Only under the nut.

I have searched for about 2 hours and cannot find a post on here about the heads sticking out too far, and when starting the car, the heads would hit the back of the motor and cause damage. I don't want this to happen.

So.... If I don't use a washer under the head, .200 will sticking up like in the first picture, is this bolt sunk in enough to avoid being hit? I know that there will be some movement in and out of the crank which could cause the bolt heads to get closer or further from the back of the motor.

Also, when I finally mount the flexplate, then the tranny, then spin the converter around to line the bolt holes up, how much can I pull the bolt out of the flexplate before it hits the back of the motor so I can add the washer and nut for the converter pads?

If anyone possibly has some pics, that would really help me out. Here are the pics that I took of how far the bolt head sticks out w/ and w/out the washer. Thank you for any help.

mark jr.

.200 protrusion w/out washer

.300 protrusion w/ washer

calongo_SS

iTrader: (7)

Looks like it's sticking out a little far, the first one might be ok, but that 2nd doesn't look right. I think you're just going to have try to turning the motor over by hand when you get the first bolt in and see how much clearance you have.
You actually have to put a nut on the back of the converter pad? The bolt doesn't just thread right into the pad?
Never seen a converter like that, the pads have always been threaded. Just may have to put a washer between the converter and flex plate if there is a big gap.

BlackDuk98

iTrader: (34)

a lot of aftermarket torque converters that I have seen aren't threaded. Every factory one I have seen is threaded. I can always have the bolt head on top of the pad, but w/ a nut and washer on the flexplate side, it is going to stick out way more than how it's pictured now.

I'm not worried about the gap between the converter pad and the flexplate. Thats a very simple fix. I am just worried about the bolt heads hitting the back of the engine and causing damage. There was a post on here once before, but the search function seemed to have changed and the keywords don't come up correctly, so I haven't been able to find it.

Anyone running one of these flexplates know the distance that I can safely have bolt heads sticking out on the engine side? Also, how much can I pull a bolt back towards the engine so I can add a washer and nut?

thanks

mark jr.

veee8

iTrader: (40)

I have had as much as .230" of the head of the bolt stick through. 1/2" grade 8 bolt. No washer is needed, loctite is a good idea though.

BlackDuk98

iTrader: (34)

Well I feel good about the dimension now. I plan on using loctite. I also picked up some grade 8 aircraft nuts. Thanks for the info. I appriciate it

mark jr.

steve40

iTrader: (18)

question for you guys, just put my converter bolts in today, and they catch the bolt heads for the rear cover. did you guys have this issue? i'm using arp bolts on the converter and stock gm bolts for the rear cover.

209ryder

iTrader: (2)

Yes i had the same problem i ditched the arp and went grade 8 with nuts on the back side

forcd ind

iTrader: (7)

i thought i had answered someone on here with a meas of the block to the flywheel-i found it, i meas from where the bellhousing hits the block to the back of the starter teeth, its aprx 7/16"-so the .300 would clear, how ever the rear cover bolts will have to be watched
i got some 10.9 metric bolts which have a washer head, or whatever you call them, and it fits in the recess-however you need American bolts, but maybe you could drill out the converter holes and use the metric bolts w/nuts if needed
you could always grind some of the head down, if your careful and get then even, balance might not be an issue

209ryder

iTrader: (2)

I tried to grind the heads off teh arp ones and beforei knew it the head was damm near gone before it would clear. So i went and got some grade 8 bolts with a nut on the back side and trqd them down and used loctite and i dont think i will have any problems with them at all. Cause i didnt feel like grinding the heads off the rear cover either and the arp ones were still reall close so i wanted to just eleviate all the stress and concerns with those bolts. But I had no problems with teh flexplate arp bolts what so ever! Good luck

bad6as

iTrader: (17)

so use no washer on the flexplate side. but use a washer on the converter side?