I see a lot of people posting with sigs saying "Vin C" etc. What is the differences in the VIN engine codes? I thought a 3800 Series I was a 3800 Series I?

Well.... with a 90 you've got a vin C 3800, not actually a Series 1.

The Vin 3 was the first, it had some little problems and only 150hp. I think you could only get it in 87..

The Vin C was a little update running 165hp, 88-91 I think...

Then we go to the Series 1 L67 (92-95) and the L27 (92-94)

Then the Series 2 L67 (96-04) and the L36 (95-04)


(Years are off the top of my head and may not be right)

Is it likely that if you had a Vin C engine completely die, they could easily replace it with a Vin L?

How could you tell?

Only reason I ask is because when my org engine in my 91 died in 2000, they said they put an "improved" 3800 in it. They gave me some technical details, bored out more(?) and other things, but I didn't pay attention really.

Have seen an 88 "C" replaced by an "L" and the original "C" computer and PROM still worked despite about a 30% increase in airflow capability between the "C" and "L". In that case the "L" was for a TranSport which did not have an EGR (quite surprising).

'88 "C" also received roller lifters.

Original cams were quite ded with "C" torque peak at 2000 rpm. As years went by, cams got hotter but even current ones are mild by '60s standards.

Exhaust manifolding of "C" engines was terrible. Front side was pretty good but rear to the head pipe is jus a ragged hole in the log with an effective flow area of about an inch and a half instead of the 2" pipe you see. I suspect this was for ease of installation into the car as a proper arrangement might not have been able to be dropped in from the top.

And just for *&G the 165hp was the same as the XK Jaguar DOHC 3.4 liter 6. Just forty years earlier.

Every time I post, I'm amazed by the collective knowledge these forums have . You've answered just about every question I had. Thanks!

Where would the torque peak with "L"?

From what I recall I find my power comes at 3000-3500rpm... ie.. that'* when the car starts to really move.
Anyway I can tell if it'* a C or L in there?

Easy way is the "C" engine has a log style plenium on the intake manifold (looks a lot like a 1957 Rochester FI) and the "L" engine has the "snakes" plenium (several curved tubes over the top).

I think I've got the "log" style....

Here'* a pic of my engine....

Yea I know I really need to clean it better.

I thought it was 210lb-ft @ 2000?

oh, and don't worry Merlin, my engine'* even worse



and what about that alternator? Mine looks practically the same as Merlin'*

Interesting spec info here. 3800 has a very mild (less than 300 degree) cam with a very broad and flat curve (how you can have 200 lb-ft at 2000 rpm and still 167 lb-ft at 5200 (84% of peak), a 3200 rpm torque band is very wide.

This makes sense since for maximum efficiency you want the torque peak at the maximum cruise speed and most Bonnevilles are barely turning over 2000 rpm at 70 mph in o/d lock-up.

Cars of the 60'* and 70'* had axles considerably longer, I had a '72 LeMans wagon with 400 cid and "economy" (3.0 axle and it was turning 3200 rpm at 70. This was a big part of the 15 mpg max. Correspondingly, the torque peaked somewhere between 3000 and 4500 rpm depending on the state of tune.

This meant when you jumped on it from a stop light, the torque converter jumped to the 2200 rpm stall speed and then began to wind with the torque constantly increasing until you hit the peak. This gave you that "feeling of accelleration" which was really feeling the *change* in acceleration.

OTOH the "C" engine jumps immediately to max torque (what gives you acceleration) and just holds it near there until time to shift (which is in the 4000s). That constant acceleration means it does not feel like it is going faster, it just does. This is why many people are surprised when they look down and see how far the speedo has wound around.

BTW "real world" 0-60 for a good running Bonne with a "C" engine is around eight and a half seconds which is really pretty quick, it just does not seem like it.