MONZORA redux: ‘65 Corvair + ‘94 Corvette mashup for 2019 Challenge

In reply to AngryCorvair (Forum Supporter) :

I don't know hardly anything about LT1s, but my truck is a '97 L31 SBC, and several years ago I had some really slow cranking hot starts. Apparently sometime in '98, GM switched to a gear reduction starter that is much smaller and stronger that the direct drive starters in years previous. I switched to one of those (cross referencing parts for a '99 SBC truck) and my issues went away.

I assume that you may have the stock starter from the LT1 which may? be a direct drive unit. I don't know if you'd want to try to throw another starter at it, but i'd be happy to find a part number for you later today. I imagine it would fit on an LT1 the same as an SBC.

EDIT: L31 direct starter is AC Delco 3371018. Gear reduction hotness is AC Delco 3371022. Supposedly both are designed for 168 tooth flexplates, not sure how that compares to your flywheel

In reply to AngryCorvair (Forum Supporter) :

How well is your engine grounded to the chassis?

Wait I just re-read an earlier post of yours, are you using the Audi starter? or the LT1 starter?

RacetruckRon said:

In reply to AngryCorvair (Forum Supporter) :

How well is your engine grounded to the chassis?

Solid engine mounts, solid crossmember mounts, plus a 2ga cable about 24" long from block to chassis.

budget_bandit said:

Wait I just re-read an earlier post of yours, are you using the Audi starter? or the LT1 starter?

Audi starter (1.2 kW vs LT1 1.4 kW)

Audi flywheel ring gear, something like 117 teeth vs LT1 153 or 168, whichever it was. 

Obviously the only solution is 2 starters.

In reply to AngryCorvair (Forum Supporter) :

drat. There goes my advice!

Are your ground cables new/good condition? My Trans Am had a ground cable from the block to the body break inside, visually i couldn't tell anything was wrong, and it slow cranked really bad and smoked the little auxilliary ground wire to the fender lol

You have 30-40% less gear reduction with the Audi ring gear (depending how many teeth a LT1 has?) ..... and less oomph from the starter

AngryCorvair (Forum Supporter) said:

budget_bandit said:

Wait I just re-read an earlier post of yours, are you using the Audi starter? or the LT1 starter?

Audi starter (1.2 kW vs LT1 1.4 kW)

Audi flywheel ring gear, something like 117 teeth vs LT1 153 or 168, whichever it was. 

That is a lot less mechanical advantage for that Audi starter than the LT1 starter typically has.

I went all Department of Redundancy Department on the grounds on my truck. I have a 2ga ground on the driver's side of the block to the battery and frame and at least one of these on the passenger side block to frame.

I'm wondering if your trans/flywheel combo were offered in a diesel powered vehicle?  If so, that starter might have a higher kW motor to overcome higher diesel CR.

In reply to wawazat :

Not in North America, near as I can tell. But that was a great suggestion!

Dang

I had a great day in the garage today.

It's supposed to say 4:30 finish. Yeah, ok, so it was only a half-day. I'm retired.

I've decided to pull the transaxle to see if the behavior is any different when it's engine-only. If yes, I will investigate trans input concentricity to crank. If no, that effort is not wasted because I have to figure out how to make the LT1 starter and flexplate play nice with the adapter plate and Audi flywheel.

I also shot some regular and some time-lapse video, so maybe this weekend I'll be uploading my first YT content in a while.

So yeah, haven't even begun editing videos, but I did do some more work on the car. Transaxle is out, and it is clear that the starter is overshooting the available depth on the flywheel:

I haven't tried starting without transaxle in place, that's probably going to happen tomorrow. I sincerely hope there's no difference with vs without trans, because I don't want to go down the path of figuring that out. I kinda have an idea of how to get the SBC starter and flexplate back in the game.

That starter engagement depth looks like a problem that will eventually work itself out  

Can you space the starter back a hair and see what happens then

Dusterbd13-michael said:

Can you space the starter back a hair and see what happens then

I tried that and was met with the hellish noise of the starter spinning before engaging the flywheel.

So the solution would have to be to Bevel or cut a relief into that spacer. Damn.

Dusterbd13-michael said:

So the solution would have to be to Bevel or cut a relief into that spacer. Damn.

Yeah, I was thinking relief cut the flywheel where the starter teeth are crashing into it, see if that makes any difference. Should be easy enough to do.

I agree, just be sure to have it rebalanced afterward! 

Or just shorten the starter teeth.

AngryCorvair (Forum Supporter) said:

Dusterbd13-michael said:

Can you space the starter back a hair and see what happens then

I tried that and was met with the hellish noise of the starter spinning before engaging the flywheel.

I admittedly don't have a clear picture of the whole setup in my head but based on the picture and this comment it seems like the starter is both too deep and too far away from the flywheel laterally. 

SkinnyG said:

Or just shorten the starter teeth.

Wouldn't he need to Bevel the teeth for engagement with the flexplate still? I'm trying to picture the Machining operation in my head for that

Do not shorten the teeth. The failure to engage when spaced back proves all of the tooth length is required. Relief cut the aluminum flywheel sounds like the easy job, but did you confirm that the starter to engine ratio is adequit? Would be a shame to clearance the flywheel and still not have enough torque to keep the starter itself alive.

In reply to Dusterbd13-michael :

a grinding wheel, a file and an eyeball