Help me assemble my engine please! I'm using ARP hardware!

RemoteUzer · Sep 10, 2002

I've been searching around for torque specs when using ARP hardware and here's what I've basically found:

Mains: about 51lb.ft.
Heads: anywhere from 70-90 lb.ft.
Rods: ?

Can anyone give my more info than that? Or even perhaps a good source? I've read ARP's little tidbit of instruction: torque heads to 70lb.ft. w/Moly Lube, or 85lb.ft. w/ 30w oil. And my POS Chilton's is suspiciously low with 14lb.ft., 18lb.ft. and 14.5lb.ft. respectively.

What are torque specs anyway? They are in reference to the strength of the bolt right?

turbolover2 · Sep 10, 2002

Call ARP.

indy1979 · Sep 10, 2002

Use ARP's specs. ARP hardware has a higher tensile stregnth than stock so it can take the torque. Trust me you won't break anything. I've got my mains at 70, the head at 110, and the rods at about 50. I like to go tight on the mains and a little loose on the rods. Helps with oil pressure.

Sam

James92TSi · Sep 10, 2002

Straight from the 1G shop manual:

Head: 65-72 ft-lb
Mains: 47-51 ft-lb
Rods: 36 ft-lb

I see no reason to exceed the factory torque specs on the bottom end.. just because the ARP hardware is stronger doesn't mean you need more torque on it to take advantage of that strength.

The head can be torqued to whatever you need as long as you torque it in sequence and work up to the final torque in steps. I think Buschur runs 90 ft-lb on his, but don't quote me on that. You just need enough torque to keep the head from lifting and blowing your head gasket with high cylinder pressures. No need to overdo it if you don't need it.

Chilton's gives a lot of those torque specs as "x ft-lbs plus 1/4 turn," so the numbers in that manual will appear low. I don't trust that "plus 1/4 turn" crap anyway. Don't know why they couldn't just give you the real numbers like the factory manual does...

Nick 92 TSi AWD · Sep 10, 2002

Is this a 6 bolt or 7 bolt engine? They have different head stud diamaters and different torque specs.

Torque is the resitance to turning, but what it inderectly shows is bolt stretch and clamp load. Bolts all have a yield point, if you over torque them they stretch too far and you end up with a lower clamp load.

A tips on torqueing the mains and the thrust bearing:

• Tighten the main cap bolts to about 10 to 15 ft-lbs in order to seat the bearings; then loosen the cap bolts.
• Tap the main cap toward the rear of the engine with a soft faced hammer.
• Thread the main cap bolts in finger tight.
• Use a bar to force the crankshaft as far forward in the block as possible, to align the bearing rear thrust faces.
• While holding the crankshaft forward, tighten the main cap bolts to 10 to 15 ft-lbs.
• Complete tightening the main cap bolts to specifications in two or three equal steps.

This procedure should align the bearing thrust faces with the crankshaft, to provide the maximum bearing contact for load carrying.

RemoteUzer · Sep 10, 2002

Thanks so much guys. Sorry I forgot to mention I've got a 7-bolt. It sounds like the numbers aren't really set in stone, since I'm actually only using ARP heads and mains I think I'm gonna to do something like:

Heads: 70-80 ft-lb
Mains: 50-60 ft-lb
Rods: ~36 ft-lb

Sound good? Thanks for the reminder on aligning the thrust bearing faces, I had remembered to use that in my installation procedure. But are the steps the same for a 7-bolt which has one main girdle? Thanks again guys!

RemoteUzer · Sep 10, 2002

Well screw that idea. I just tried torqing the rods down to 36ft-lb and they weren't taking. So I took out the piston & rod only to find that the factory bolts were streching...time to get ARPs! The mains seem to be seated well though

Do ARP rod bolts require any special machining of the rods?

turbolover2 · Sep 10, 2002

Nick 92 TSi AWD said:
• Tap the main cap toward the rear of the engine with a soft faced hammer.

Tap each cap, or just the rear one?

James92TSi · Sep 10, 2002

Man I wish I had come back to this topic sooner, I could have saved you some grief with the rod bolts. The numbers I gave were for a 6-bolt. I don't have a manual that covers 7-bolts here.

Not sure if the numbers are the same or not.

I'm not sure specifically what has to be machined, but yes you'll have to have the rods machined to use ARP rod bolts. From talking with Tym over at Buschur's, the stock rod bolts can be reused once and that's it. After that they stretch too mucn and should be replaced.

Turbolover2 - just the thrust bearing cap. The rest of the main bearings don't have thrust faces. Thrust bearing is the only one you need to mess with to align.

indy1979 · Sep 11, 2002

Or if you're using the arp main stud kit. Its a very good idea to have a machine shop align hone the mains.

Sam

Nick 92 TSi AWD · Sep 11, 2002

turbolover2 said:
Tap each cap, or just the rear one?

The thrust bearing cap, it's the one in the middle. With the full girdle it is very hard. I'd say keep on tapping all the mains repeatidly, or I would even go so far as to actually cut the girdle, and make it like a 6 bolt.

For the ARP rod bolts you need to press them in with a hydraulic press, then the machine shop needs to take a little material off the rod caps, install, torque to spec, and re-size the bore. You should measure the rod journals with a micrometer, then measure your rod bearings DIRECTLY at the top, do not measure at the sides of the bearing. Decide what clearance you want to run, do the math and tell the shop to re-size the rod bore to give you the right oil clearance. Always check it with plastigage afterwards, machine shop are run by humans, and humans make mistakes sometimes.

RemoteUzer · Sep 11, 2002

Well, it's alright about the rod bolts, I should go with ARPs anyway. As for the machining procedure, I understand the line-honing because you're moving from bolts to studs which twist the caps etc. differently (and I did have this done) but when moving from weaker bolts to stronger bolts something needs to be done? Is it absolutely necessary? I talked to someone over at Buschur (didn't get the name) and they didn't think anything needed to be done to the rods. If I were to put the things together, throw some plastiguage in, torque them to spec (whatever the heck that is) and the clearances end up being OK, couldn't I just keep it like that?

indy1979 · Sep 11, 2002

If your going to go thru all the work of building this block, go ahead and blueprint it. There are only 2 size bearings for these engines (I know, I looked) standard and .25mm oversized. Its best to machine the crank journals, unless its brand new, cause you never know if its out of round. If its not out of round there is a trick I used to bring the oil clearance down to where I like it. I'm using standard bearings and all I did was shave the caps down and plasti-gauged it until I had .00175 on the mains and .002 on the rods. I did this cause it will bump up my oil pressure a little bit.

As for the rods, I'd have them shot peened and cryo treated to get them strong again. If your looking for the .25mm oversized bearings I have a set still in the box.

Sam

RemoteUzer · Sep 12, 2002

Well, I can appreciate making things as perfect as possible, but there are limits to how perfect I'm going to make them, the first being money and the second being time

I do have a new crank and when I checked the rod bearing clearances, before the streching, they were all the same and all within spec. The question stills stands: how necessary is this 'rod machining process' just for ARP bolts?

Nick 92 TSi AWD · Sep 12, 2002

indy1979 said:
Its best to machine the crank journals, unless its brand new, cause you never know if its out of round.

4G63 crank journals are nitrided stock. Ideally during the tufftride heat treatment (crank is heated to about 800 degrees F and put in cyanide salt) surface penetration will be .200" into the metal. It is a very inconsistent treatment though and some times simply polishing can go right through it. Turning the crank will definetly go through it.
Unless you find a crank shop that will perform the nitriding procedure do not turn a dsm crank. I have seen one car with a turned crank, snapped the crank at the #4 rod journal.

Help me assemble my engine please! I'm using ARP hardware!

RemoteUzer

turbolover2

indy1979

James92TSi

Nick 92 TSi AWD

RemoteUzer

RemoteUzer

turbolover2

James92TSi

indy1979

Nick 92 TSi AWD

RemoteUzer

indy1979

RemoteUzer

Nick 92 TSi AWD

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