4,000 rpm + driving?

[Dale .D]

Hi guys.Just had my 32\36 dgev weber rejetted very close to takenaars suggested jetting.Finally found a very expierienced carb guy that specialized in european vehicles.Feels really good but haven,t had a chance yet to really put it through it's paces.This guy does Rolls Royce & Jags & all the fancy stuff & said he had a real ball with mine. He increased my timing by 5 % & said besides the jetting my secondaries were barely being opened.He also said that you don't really feel the power untill after 4000 rpm! Heck after doing a bunch of motor work last winter ( sprint ,ported intake ,Chroming ect)I've been treating it kind of gently,Rarely going over 4000 rpm.My question is is it abuseing my car to regularily go over that rpm. Did it yesterday & it was a blast but want to know if it's going to damage it.Any advise would be great . Thanks Eh

[hrcollinsjr]

Originally Posted by Dale .D ...I've been treating it kind of gently,Rarely going over 4000 rpm.My question is is it abuseing my car to regularily go over that rpm. Did it yesterday & it was a blast but want to know if it's going to damage it.Any advise would be great . Thanks Eh

When I had a running daily driver my wife use to abuse it regularly. She called school volleyball matches and they couldn't start until she arrived. I use to worry that the ticket would be more than the match paid. If the engine is sound it should be fine.

Harold

[newman27]

FWIW, 3.5K - 4K is about where I shift each gear on a regular basis (normal driving) while going over 4K occasionally such as when trying to get around someone in a hurry. That may be why I average 18 - 19 MPG though. I've always thought that four cylinder cars liked the RPMS...

Matt

[Dennis Texas]

if I'm not mistaken 4000 rpm ~ 70 mph or about that.

[Anonymous D]

Experience on other European cars, does not necessarily mean comprehensive knowledge of an Opel. If your secondaries aren't opening, that likely means that either you need to install an "L-shaped" linkage bracket adaptor to the Weber (instead of swapping over the Solex linkage, as so many so), or you need to re-adjust your mechanical throttle linkage (lengthen the adjustment on the vertical rod that's connected to the gas pedal, shown as "4d"). Info is on pages 4 & 5 at:

http://www.opelclub.com/TuneUpPart1bJune2006.pdf

[kwilford]

Originally Posted by Dennis Texas if I'm not mistaken 4000 rpm ~ 70 mph or about that.

3500 rpm at 70 mph in a GT, to be precise, with the stock transmission and tires and the 3.44:1 differential.

These engines are "over-square", meaning bigger bore than stroke. Also meaning they NEED to be revved to attain decent power, not to mention decent fun. Rev away, McDuff

[Dale .D]

Eh "A" Had the L shaped adapter & I guess it needed some adjustment.An experienced Opel carb guy up here in the great white north except for Calgary of course is as rare as two tits on you know what so we treasure what works..

[Dale .D]

Originally Posted by kwilford 3500 rpm at 70 mph in a GT, to be precise, with the stock transmission and tires and the 3.44:1 differential. These engines are "over-square", meaning bigger bore than stroke. Also meaning they NEED to be revved to attain decent power, not to mention decent fun. Rev away, McDuff

Eh my ( jamaican Bob sled team.)( Eddie they eagle,I remember it well in the Bowness hotel) I would like to learn more about bigger bore than stroke.Please explain??

[Phoenix]

Mine is a daily driver and is regularly at 4000 rpms. 80mph cruising and sometimes shifting through the gears.

[Paul]

4000 is no problem even for a stock low compresson engine. 1st and 2nd have enough power to warrant shifting at 5500. You can't hurt anything except gas milage... To me, for the normal driving 4500 is a better shift point.

I frequently shift at 6500+, but I've done a bit more work to mine... I just like the sound as it begins to wind up

[hrcollinsjr]

Originally Posted by Paul 4000 is no problem even for a stock low compresson engine. 1st and 2nd have enough power to warrany shifting at 5500. You can't hurt anything except gas milage... To me, for the normal driving 4500 is a better shift point. Watch the tach and when the rate of acceleration starts slowing down probably in the 5K to 5.5K range that's probably has high has you need to shift. I frequently shift at 6500+, but I've done a bit more work to mine... I just like the sound as it begins to wind up

On a stock engine at 6500+ RPM, all he'd be getting out of it would be sound!

Harold

[RallyBob]

As with almost any German car....you can run it at max speed all day long.

[Dale .D]

Can anyone explain the over square or larger bore than stroke principle for the 1.9 .Why would the bulk of the power be in the higher rpm.Not questioning it ,just want to understand it?

[RallyBob]

Originally Posted by Dale .D Can anyone explain the over square or larger bore than stroke principle for the 1.9 .Why would the bulk of the power be in the higher rpm.Not questioning it ,just want to understand it?

Oversquare engines have less torque generally, but they're more proficient in the higher rpm ranges IF you have the breathing/camshaft upgraded to suit it. It mostly has to do with the inefficiency of the short stroke engine to 'pull' air and fuel into the engine...imagine filling your bicycle tire with a hand pump but only using half the travel available to you...you need to pump it twice as fast to do the same filling.

The big performance advantage of the smaller stroke engine is that it has a lower piston speed, therefore it tends to be more reliable at high rpms and has less wear.

For example, a 1.9 litre engine has a 69.8 mm stroke (2.748"). In one revolution of the crank, the piston goes up 2.748", and down 2.748", so it travels 5.496" is one crank revolution. At 8000 rpms, that equates to 43,968" (3664 feet) of travel in one minute! By comparison, a 350 Chevy has a 3.48" of stroke, and at 8000 rpms the pistons travel 4640 fpm. That's over 25% higher piston speed at the same rpms. This is why large displacement high rpm racing engines need VERY strong parts to cope with extreme rpms.

[bigjim5551212]

on my Lemans (opel kadett E) i rev it till it hits the rev limiter. It loves it

[DennisGardiner]

Originally Posted by Dale .D ...going over 4000 rpm.My question is is it abuseing my car to regularily go over that rpm...

If you have bigger cam, and you plan to take advantage of the HP,... drive it hard.

I had a built engine (with a huge cam) yeasr ago that did not even come to life until I went past 3000 rpm. From 3000 to 7500 rpm that engine was 'all-go'.

Under 3000 she felt like I was towing a trailer.

With my L98 V8 she screams at 5400 rpm,... and I do mean screams!
Have not been pulled over,... yet. But then I don't drive in Opelwasp beat.

[opelwasp]

I wouldn't pull ya over either. As far as by fellow officers, if you're driving the Opel you'll probably be fine.

[Dale .D]

Originally Posted by RallyBob Oversquare engines have less torque generally, but they're more proficient in the higher rpm ranges IF you have the breathing/camshaft upgraded to suit it. It mostly has to do with the inefficiency of the short stroke engine to 'pull' air and fuel into the engine...imagine filling your bicycle tire with a hand pump but only using half the travel available to you...you need to pump it twice as fast to do the same filling. The big performance advantage of the smaller stroke engine is that it has a lower piston speed, therefore it tends to be more reliable at high rpms and has less wear. For example, a 1.9 litre engine has a 69.8 mm stroke (2.748"). In one revolution of the crank, the piston goes up 2.748", and down 2.748", so it travels 5.496" is one crank revolution. At 8000 rpms, that equates to 43,968" (3664 feet) of travel in one minute! By comparison, a 350 Chevy has a 3.48" of stroke, and at 8000 rpms the pistons travel 4640 fpm. That's over 25% higher piston speed at the same rpms. This is why large displacement high rpm racing engines need VERY strong parts to cope with extreme rpms.

Great info Bob.Thanks.I remember in shop about 30 years ago seeing a boss 302 & comparing it to my rebuild of my 283 ,seeing the big difference in the length of the con rods.Totally different animal.My 71 gt only has 60000 miles on it now & for the most part is mostly stock.If i ever do a rebuild I'll do the cam change then.So am I right to conclude that because of the lack of sucktion do to the short stroke ,it parcially a factor in having to crank a little more than you want to start ther car when it is hot? or am I way off base.

[jeff denton]

My Opel seems to enjoy my driving method. Which is to gear it for the speed I want, and run it wide open throttle at just over 7000 rpm. Let up on the gas a tad for the corners and put her to the wood again.
It's a little rough on tires and fuel mileage isn't what it should be, but it's fun.

Oh, both your spelling teacher and your physics teacher might have a problem with the "sucktion" thing. Engines don't suck. They reduce the pressure inside the cylinder so that atmospheric pressure can push air into it.

[wrench459]

Originally Posted by Dale .D .He also said that you don't really feel the power untill after 4000 rpm! Heck after doing a bunch of motor work last winter ( sprint ,ported intake ,Chroming ect)I've been treating it kind of gently,Rarely going over 4000 rpm.My question is is it abuseing my car to regularily go over that rpm. Did it yesterday & it was a blast but want to know if it's going to damage it.

IMOA don't start it up..thats where the most wear occurs.Very little oil film to protect the mating surfaces.
Looking at your mods I would twist that little motor. It does have a nice rod ratio to bad the driveline is so weak.

[kwilford]

Originally Posted by jeff denton Oh, both your spelling teacher and your physics teacher might have a problem with the "sucktion" thing. Engines don't suck. They reduce the pressure inside the cylinder so that atmospheric pressure can push air into it.

I am starting to suspect that the combination of a faked Jamaican accent and some genuine British Columbian 'shrooms (or maybe just Columbian cannabis?) have conspired to create a whole new version of Canadian spelling rules

[lezliewk]

I came back from Springfield last year at about 78 mph at 3850 rpm's
I have pictures in my photo's showing it. It used a bit more gas coming home than it did on the way over. only made about 60 going over

[Dale .D]

Originally Posted by kwilford I am starting to suspect that the combination of a faked Jamaican accent and some genuine British Columbian 'shrooms (or maybe just Columbian cannabis?) have conspired to create a whole new version of Canadian spelling rules

Sorry. Guess I better start useing the spell check. Mushroom season on the coast is over now bud there's another season of harvesting happening now.Have you heard Bob & Doug & Cheech & Chong are both going on tour. Should be good Eh! Car's working great now with the new jetting & with the secondaries .fully opening

[jeff denton]

I did hear Cheech and Chong are making a comeback. I hope they're putting out a better message this time. What was funny then just isn't now.

[West Coast GT]

I don't normally run my car at 4000 rpm. It just doesn't feel right to run an old engine that high.

But I took it out for a quick run (all freeway driving) to go look at an old Volkswagen show in Vacaville. Round trip was between 50 and 60 miles and I kept it at 4000 rpm most of the time. I've got to admit it runs smooth, very smooth at the higher rpm.