Hello everyone back again.
I recently got an aluminum flywheel from Fidanza to put on the 98 sc2 engine I rebuilt. But I am having a heck of a time trying to find the correct bolts to attach the flywheel onto the engine I ordered some bolts from Rockauto that were suppose to fit my Saturn and they were the wrong size and they only came in a pack of 6, also every jobber it telling me Saturn's only have 6 flywheel bolts. I have 8 threaded holes in the crankshaft. I have some M10x1.5 bolts and it really wont thread onto the crank very far....these were the bolts that held the flex plate to the converter of the doner 97 I pulled the engine from that and it is temporary in my 98. First off the flex plate bolts were to short and there is only 4. They are M10x1.5 will not thread in but a few turns. I have a bolt and nut size gage. Does anyone here know the correct pitch and length that I would need? I want new bolts class 10.9 so even if I could find a junker I would not trust them as I am sure they are torque to yield.
Thank you for your assistance
Radtek2

 

Your aluminum flywheel is probably thicker than a stock steel flywheel. Do you have a bolt that matches the threads in the crank? A 10 x 1.5 is a course thread bolt. 10 x 1.25 and 10 x 1 are standard pitch for fine threads. I would try a 10 x 1.25 first. Bolt length is usually in increments of 10mm. How long are the bolts you received from Rock Auto?
First thing to do is to determine diameter and pitch. Then determine what length you want to run, try to maintain factory bolt depth into the crank. You may have to purchase longer bolts than you need and have to trim them to the proper length.
This is the joy of not running factory parts, you have to determine exactly what you need.

I live in a small town of 10k people. A local Ace Hardware has a nice assortment of metric bolts in 10.9. If I need anything specialty I have to drive 30 miles to a larger city. There is a very nice hardware store that has just about anything I need.

 

Thanks for the reply
I live in small town also 20 miles to anywhere it seems. I don't have the bolts from Rockauto I sent them back but they were a much larger diameter. I know in my Haynes manual they show the flywheel with only 6 bolts and they must have been larger. Yes the aluminum flywheel is thicker the holes measure 10.8mm and the old flywheel from the 98 is 8.55mm. A difference of 2.3mm.The depth of the cranks bolt holes bottom out at 17.45mm so total of 28.25. So I am thinking I need an M10x25 but I don't know what the pitch is. I dont have a bolt that will thread into the crank to measure the pitch....I guess I will have to go buy separate bolts of each size pitch and bring them home and try them out to see what I need. If only there was a site or manual that had the listing of bolts needed for the flywheel to crankshaft I would not have to run back and forth to just bolt the flywheel to my engine! Do you think the M10x25 would be the correct length and still have enough grab with not bottoming out?
Radtek2

ek2

 

I would probably buy 10 x 30 and add a flat washer. Do you have your old bolts that are too short?

 

The flywheel manufacturer said not to use washers with this flywheel. I went to the local Tractor Supply and found some regular bolts M10x1.5 and M10x1,25 but they did not have any m10x1.0. The 1.5 and the 1.25 will only thread into the crankshaft about 1/8 of an inch. I did find some Flywheel bolts M10x1.0 on line and they do have a pack of 8 ....ARP for $50 ...no way am I going to spend that much on 8 bolts! I was able to buy from Amazon a single M10x1.0 bolt...I also bought 3 cleanup taps in the 1.5,1.25 and 1.0 size just in case I buggered the treads a bit trying try fit the wrong size into the holes. I do have every size from huge to small, fine thread to coarse in SAE, I've collected in the last 60 years but no metric. To address having old bolts, the bolts I had are now in the 98 with the donor engine. The 97 donor was an automatic, so I got a new standard flywheel and clutch components from LUX for that engine but had to use the bolts from the 98. I can order M10x? grade 10.9 flange type from other bolt manufactures' as soon as I find what size I need. Saturn's' you gotta love them to work on them!

 

Many of the folks over at sixthsphere.com fitted the Fidenza flywheels on their S cars back in the day..... Along with standalone controlled turbos and other mods

I'm confident someone there will have the answer. Maybe not off the top of their head but someone will know where to look it up.

They also have a sixthsphere Facebook group where most of the action happens.