What is my redline?

[ditch68]

My car (though it is an earlier car) has a 1969 911T engine. The tach has an indicated redline of 7200 RPM (!)

There is NO WAY I plan to rev it that high...all the technical info for that engine I can find indicates max SAE HP at 5800 rpm.

I have only had it up to about 5500 rpm. (I have a slight fuel starvation issue above that at WOT.)

Can 7200 be correct? I doubt it. Or am I wrong? I'm not sure where the tach came from.

Jeff

[Rot 911]

You have a tach that belongs in a 911 with a "S" engine. Yours should show a redline of 6200. Someone with a 911S would give you some decent money for that tach.

[Shaun @ Tru6]

Let's see a pic of your engine.

[ditch68]

Thanks, Kurt. I didn't think that was right.

Shaun, here is a pic of the engine when I got it. I assure you, it does NOT look this ratty now, I have detailed it, and added air cleaner elements, etc.

I know the red fan shroud is an indication of an "S" engine, but it has Webers, and the shop I bought it from said the same thing - he saw the red shroud, thought it was an "S", but checked the numbers, and assured me it is a "T" engine. My car is truly a pile of parts...5 cars were donors, and counting.

FWIW, the engine number is 6196295.

Brace yourself...the engine looked horrible when I brought it home...

[Shaun @ Tru6]

Amazing what PO's will do. I'm guessing you don't have any sort of repair history? While it's easy to just pop on a red shroud, I'd be curious to see if any work was done to the motor that would necessitate the S tach.

Does is drive like a worn out T or does it have something extra?

[ditch68]

Well, I feel it pulls a lot harder than one would expect a tired T engine to.

My last car was a 1988 924S, the 160hp one with the 944 engine. This car feels much faster, especially in the higher RPM range, feels like more power to me.

I don't know, I guess it will be a mystery until I get the engine apart some day.

Someone did put a lot of work into this thing, all the body work, interior, all swapped for later replacements. Perhaps the "hot rodding " included the engine?

Jeff

[Shaun @ Tru6]

worth doing a compression check, and if dyno time is $100 or so, out of pure curiosity I'd take it for a couple of pulls, AFTER valves, timing, head studs, etc. have been checked.

[ditch68]

Will do. I will have to find a dyno in town. Shouldn't be a problem. I am planning on doing the valves, timing, etc. anyway.

Any other telltale signs I could look for externally, or with minor disassembly? (are cams marked where they could be seen with the chain covers off?)

Compression check, yes. I have checked for cross cylinder consistency...not sure how to do ratio.

The car does have headers, is this a stock exhaust? (however crumby it is)

Jeff

[Zeke]

I can't find it in a quick reference, but I think the redline on a T is 6500. IIRC, it's 6900 on an E and 7200 for the S.

[jluetjen]

At what engine speed does the engine "come on cam" and start to pull strongly?

Also, have you ever pulled off intake manifolds and measured the ID of the intake ports?

[Gogar]

Hey, make sure to pull your sump plate off and rotate it 90 degrees clockwise from where it is in that picture, so the drain plug is on the Driver's side of the car. You'll enjoy a psi or two of oil pressure that way.

[Flieger]

I thought that only applied to the 930 and 3.2 Carrera engines with the oil pumps with the integral pickup tube screen.

[slodave]

Originally Posted by Flieger

I thought that only applied to the 930 and 3.2 Carrera engines with the oil pumps with the integral pickup tube screen.

3.2's don't have a sump plate. Well, I think that there are a few really early ones that do.

Where's my burrito?

[Flieger]

Whoops, I was thinking of that photo in Wayne's engine rebuild book where he shows the sump plate without the drain plug.

[Matt Smith]

Give it a rev to 7200 under load and see if it still makes power. I doubt very, very much you'd kill it. There is a distinct possibility it has been rebuilt with mongrel S parts, so give it some booty and save yourself some dyno time. It will be obvious if it likes it, but my T will rev there no worries when asked- just stops making worthwhile power..

[Plavan]

What do the cylinders look like? Cast iron or aluminum?

[jluetjen]

Chad; I'm not sure if it will make any difference. The real key parts are the following:
1) Cams
2) Pistons
3) Ports

It's pretty hard to confirm the pistons without taking the engine apart. The ports can be measured by removing one of the intake manifolds. The cams can either be measured directly, or else by where the power band is in the car. If it pulls strong from 1500 RPM up to 5000 RPM, it's most likely got T cams. If it pulls strongly from 2500 - 6500 RPM it's most likely got E cams. If it pulls strongly from 3500 - 7000 RPM it's most likely got S cams.

Given that the engine has been rebuilt to non-original specs, such things as the shroud or the cylinder material don't really tell you what the builder put inside.

[ditch68]

John,

Driving home today, I paid close attention to the car as I drove it, I had plenty of opportunities to lean on it in all gears.

The cams turn on like a switch at almost exactly 3,000, (maybe 3,200?), and it pulls hard all the way to near 6,000. But I have a fuel starvation issue at WOT above that, so I let off because I have to...

If what you say about 1500-5000 being T cams, there is NO WAY that's what is in there. Not really even the "E" profile seems to fit, maybe 2,900 at the lowest it starts to pull. Like I said, around 3,000 RPM and it sets me in the seat, especially in second gear. Third puts it right back in that band, and woo hoo. It really is somewhat dramatic in second.

I would be just thrilled to find out I have something a little more special than a stock "T" engine. It may be looking thaty way. Maybe the Webers were not so good an indication. I don't plan on pulling the intakes soon, but if I have some free time I may next week.

I will look closer at the jugs, also.

Jeff

[jluetjen]

It sounds like you most likely have something like S cams, and I assume the appropriate pistons since it doesn't sound like the valves are hitting the pistons. So it sounds like you have a tuning problem.

1) I'd check the timing at both idle and 6000 RPM.
2) Pull off the intake manifolds and see what sort of intake port size you have. It would also be helpful to check the manifold size where it meets the heads.
3) Check the carbs to see what size venturi you have, as well as the jetting and emulsion tubes.

Your exhausts are the standard heat exchangers which are most likely fine for your application. They are good for upwards to 210 HP and I doubt that your engine is putting that out.