Can somebody measure a 3800 for me?

[carkhz316]

Title, basically. I'll send you some beverage money for your time. Firstly, for the 3800, I'm after the measurements on the transmission/ rear end of the motor. I don't have my MC ripped apart yet, and wanted to compare the crank to bellhousing depth difference. For example, on the LS4, the crank mounting/ hub surface is only recessed about .007" relative the the bellhousing/ engine mating surface. I cannot find these measurements for the 3800 for the life of me. If these measurements are similar, then it would be safe to assume the flywheel for the LS4 should be the same thickness (.840") for my trans swap to keep the clutch situation simple. Thanks for you time!

[pwmin]

I have an L67 torn down to the block, but won't be to where it is until Monday. 

[carkhz316]

That would be terrific and I don't mind waiting since I haven't been able to find any measurements at all. 

[pwmin]

I'll put something in my phone calendar so I remember

[pwmin]

I guess I'm just dumb, but could you help me out with what exactly you want me to measure?

[carkhz316]

So if you place a straight edge across the bellhousing flange on the motor, I just need to know the relative distance or recess of the crank flange hub (the outer portion the flywheel bolts to.) It should be nearly flush or only recessed a few thousandths of an inch.

[pwmin]

I believe this is what you're looking for?  If I'm measuring correctly, I get about 5/64" (~.008"). 

[carkhz316]

It's kinda hard to tell from the last picture but it sounds right. Hopefully my crude drawing helps (forgive me I just did it with my phone)

[carkhz316]

The red would be the air gap between the crank hub and your straightedge, but if you are seeing it almost flush it sounds right

[pwmin]

It's hard to get the right angle so it looks right especially with it on a stand.  This picture might give you better context. 

[carkhz316]

Here, another crappy drawing showing the two reference points

[carkhz316]

So on your last picture, that'd be the timing cover. If you go just inboard (to the left) of that, that the crank flange I'm referencing.

[pwmin]

The timing cover is flush with the engine bellhousing.  The crank flange sticks out very slightly from the bellhousing.   I'm fairly certain the measurement I took is correct.  I can't get a straight edge across the bellhousing with the stand in the way but putting it across the crank flange, the bellhousing is slightly recessed from the crank flange.

[carkhz316]

Here, one more. Hopefully this makes sense.

Green is the bellhousing mounting pattern, and the crank flange

White is your strsigted across the bellhousing (might be difficult with the engine stand I realize)

Red is the small gap in between the straightedge and the crank flange

 

[carkhz316]

Okay it sounds like you got it solved then. I was pretty sure it would be best flush and you've pretty much confirmed as such.

[pwmin]

I'm thinking the 3800 is opposite of the 5.3, as the crank flange is slightly out from the bellhousing instead of being recessed in relation to the bellhousing.  You might need a small spacer if I'm getting it right.

Edited February 8, 2021 by pwmin

[carkhz316]

That is perfectly fine, because it would allow running the flywheel a bit thicker than I expected. The LS4/ F40 flywheel is like 1.5 inches thick, so it'll still have to be machined down some. I appreciate your time and help. PM me your paypal and I'll send some beverage monies

[pwmin]

Okay, cool.  Glad I could help you get it figured out.  You don't have to do that, I'm more than glad to help with your project in any little way I can.  If you feel you must, my paypal is the same as my yahoo email in my profile.