VAC Torque plate-what bolts?

[medgingt]

I provided my machinist a VAC torque plate and factory head bolts. The bolts are too long to use even with the spacers the plate comes with. I tried calling VAC and they said their tech support guy is on vacation, so they were going to try the engine shop but just wondering if anyone here knew what to use for bolts. 8.8 with the right length? 12.9s?

Thanks

[moatilliatta]

Make some spacers that would work. Use the hardware you're going to use when assembling the motor. IE New head bolts or studs.

[medgingt]

That's what I was hoping to do, and why I provided the factory bolts. I suppose getting some spacers wouldn't be too bad. Why on earth didn't VAC just make them the right size...

[digger]

That's what I was hoping to do, and why I provided the factory bolts. I suppose getting some spacers wouldn't be too bad. Why on earth didn't VAC just make them the right size...

clearly the torque plate plus spacers should be the same as the head but you know.......cause VAC.

in any case you need fasteners that give the same clamp as what will actually be the case so you could potentially buy a different length bolts same grade as actuals if equivalent to what you are using but this is unlikely to be true unless using metric blues or similar

[ForcedFirebird]

Spacers and hardware in a lot is moot since you need to use the fasteners that will be on the end product. That's not on VAC, that's on the end user. That being said, I have played around with fastener and clamping force. As long as you have the length/type of fastener, and thread engagement, there will be negligible differences. So,if you are using a 1/2" (~12.5mm) plate, just use stand offs so that the threads engage as implemented, and torque values can be met.

[ForcedFirebird]

To add: Its much like that argument about changing from stock to ARP on main/rod caps.

Does it work if you "just slam them in there"? Sure, it will probably run fine. Is it correct?

I would say no, there are clear differences when measuring a big end or main when using a different fastener. Period. The. End.

[digger]

Spacers and hardware in a lot is moot since you need to use the fasteners that will be on the end product. That's not on VAC, that's on the end user. That being said, I have played around with fastener and clamping force. As long as you have the length/type of fastener, and thread engagement, there will be negligible differences. So,if you are using a 1/2" (~12.5mm) plate, just use stand offs so that the threads engage as implemented, and torque values can be met.

IMO it is on VAC. why provide spacers the wrong length just supply it with the proper ones so the bolts intended to be used can be used directly.

[medgingt]

IMO it is on VAC. why provide spacers the wrong length just supply it with the proper ones so the bolts intended to be used can be used directly.

I agree...I can't fathom any good reason the provided spacers shouldn't match the head height. Anything else can just lead to the wrong fasteners being used.

[ForcedFirebird]

The plate can be used for all baby sixes, and there's different fastener lengths. Well, from m20 to m54 anyways. The n5x motors have an asymmetrical pattern where the end cylinders don't match the centers. (Edit: m4x and m6x also have the same bolt pattern - they all fit on my flow bench adapter).

Stacking washers is fine, even. The most important thing is to have the thread engagement and TQ value mimicked. Granted, for what they charge, it should come with all sized spacers. Their site was the first time I saw mention of ”Intake and exhaust valves are balanced and blueprinted".

There's been a lot of discussion around this on machinist boards. One person was able to match the distortion just by putting the head bolts through wrist pins and torquing them down without any plate.

I made my plate. Wasn't difficult, scanned a head gasket, had it roughed out on water jet, then tuned in on the mill. It pulls double duty, honing and pressure testing. Had it for years, think I paid the water jet like $60 at the time.

[digger]

I agree...I can't fathom any good reason the provided spacers shouldn't match the head height. Anything else can just lead to the wrong fasteners being used.

This is why designed and got one built myself