Engine and Transmission Tech

Perry, great job ! What is your estimated hp ? What crankshaft is surviving this torture ? Rods ? Cheers, roverman.



Edited 1 time(s). Last edit at 07/21/2014 11:30AM by roverman.

Hi Art!
Sorry for the delay in replying. Work has been hectic and then I had my holiday and I'm just back in the UK now.

Dyno HP was 525 with 12psi and a 150 shot of gas. But the run was cut short as the slicks pretty much caught fire on the rollers with full power. So I guess its 525hp+ ? Since that time I have added another 25 shot of gas. My ESTIMATE is 600hp with 600 ft/lbs at this time.

The crankshaft is a stock Rover 3.9 that has been offset ground. The rods are stock Chevy 5700's.

The torque converter is only rated for "up to" 350hp so I'm not surprised thats its slipping a little now.

I spoke to Caon Racing and gave them all my specs and they said I need a converter that will handle over 800hp with a stall sped of 4200-4500 rpm. My present converter is a 3000 rpm stall item from B&M. So i know I wont get any better on the track until I swap out the converter and start testing again. I can see that this extra half a second on the track is going to be expensive now :)

Even tohugh the MG is suffering with tranny issues I took it out for a weekend at the Mopar Nats here in the UK. The MGB was given a warm welcome by the Mopar Muscle guys and I had a great weekend.

I was trying to make some adjustments with the nitrous and boost so as not to over power the converter and the results were good and not so good overall. On the Saturday she ran reasonably well but she struggled to get below 9.8 on the strip. And on one of my runs i got it all wrong and had the most odd launch which my friend caught in slo mo. I hit the pedal and she backfired and died for a split second. So I backed off and got back on the pedal again. By this time the car was all over the place. But I kept my foot in for a real funny launch as you can see in the vid. The run wasnt very good but the slo mo makes me laugh everytime I see it :) I even felt a litte tyre shake ??

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Then I got back on Sunday morning and ran a 9.62 straight off the trailer with no drama which made me smile and also set the tone for the day ahead. As the air temps rose the car got slower as usual and for 2 runs I was on my own as nobody in the queue wanted to race me ? WHAT!! I was in the RWYB queue and two times in a row the guys next to me in the queue held back when we were called forward? The first guy was in a really cool Dodge Dart that looked like it was pretty well tricked out. I had been talking to him for an hour in the queue. But when we got called forward he held back so I had a solo run. The next run was going to be with a Plymouth superbird. He did the same and let me go on my own. On my next run I got to the front to be called forward and the guy in the other lane held back as well ? I called to the guy who was running the queue and asked why I had to run on my own. So he called on one of the super street class cars forward and asked him if he would race me. And he obliged. So we had a really good side by side race for my last run of the day.

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I also did a side by side with the other car I have been working on for the last 3 years while he did some shakedown passes just before hte Mopars :)
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Perry, Cool videos! I have a question on your rear axle. Did you use the crush sleeve or solid spacer?

I'm still using the original 1975 crown wheel and pinion gears Jim. The car had 110,000 miles on when I bought it 16 years ago. So it has a few more miles now. The old crown wheel was re used on the spool as you know. The only work the diff has had was new pinion oil seal when I had it apart for the mods early this year.

Perry, I thought maybe you did a custom solid spacer as the crush sleeve will take a pounding and start to loosen up.

Hi Jim
I decided to leave the diff as is. Mainly to see what it will take in stock form. I had the prop shaft off last weekend to do a box and converter swap and could not feel any play in the pinion when I heaved on the diff flange? The pinion does try to push towards the front of the car when under acceleration. But this force is held in check by the very large inner pinion bearing. So i dont think the crush sleeve will suffer much even with 700hp being put into the diff :)

I will however keep checking the pinion play as the bearing will no doubt start to suffer in the future. The inner pinion bearing is a huge item which is why I am not worried about the potential crush sleeve issue. I've seen this discussed on forums and have wondered why folk think that the crush sleeve would be affected ?
My understandng is that the crush sleeve is there to set the pre load between the inner and outer bearings during assembly.

Regards
Perry

Perry, With your auto trans you probably won't have issues. Probably the racers with manual trans dumping the clutch is what hammers the crush sleeve in some rear ends. Keep us posted!

That should be interesting Jim!
I've just swapped out the stock TH350 for a race version with transbrake fitted. And a new 4500 stall converter to replace the old 3000 stall converter so I can give it some more power on the launch :)

I'm going to take it easy while I learn how to use the transbrake though. I do not have a launch rev limiter setup yet. So it will have to be "seat of my pants" launches for the time being !

So in anticiaption of the harder hits off the line I'm going to wind up the slapper bars so they are pretty tight on the rear springs to make the rear end a bit more solid to improve the 60 foot times if I can. I have a wheelie bar kit ready to fit if required, but I would love to run 9.5 or quicker without wheelie bars if I can. ??

Perry

Well !!
I went out last weekend and did some testing. And what a fool I am :)

I did 5 test passes and 4 of those test passed saw me shifting from 1st to N ?? I had real problems teaching myself to pull the stick backwards on the new gearbox after the launch. At least i know that my rev limiter works I guess :)

On the one pass where I actually got the gear shift right, the tyres let go in 2nd gear so the run was quite slow.

As I tried each pass on the T Brake I increased the launch rpm. On runs 4 and 5 I held 4000 on the T brake and made 1.4 and 1.5 in the 60 foot (these were non nitrous passes) and still hit 10.9's with the missed gear shifts. It was 1st gear off the line, and then neutral, and then hear the limiter popping and pull back twice to 2nd and then again to 3rd gear. I'm hoping that when I go out again I will get it right and run a 10.7 on boost only. When I do that I will turn the gas back on ??

Perry, Thanks for keeping us posted!

I forgot to post a video :)

This is me missing 2nd gear again !

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Its nearly time to go racing again :)

I have been practicing my gear shifts and if all goes well I will find my 10.7 with no gas on Saturday.

If i can do a couple of pulls and get my shifts right I will turn the gas back on. Then i will be wanting to come home with a 9.5 timing ticket in my pocket !

Wow, Perry. A nine second quarter in a Rover powered MGB! Wouldn't that be spectacular.

Jim

Can't wait to watch the video!

Jim!!

I've been running mid 9's for a year now. The norm is a 9.6 when all goes ok. I've done around fifteen 9.6 passes now :)

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I'm acutally hunting an 8 second pass from now on !

The new torque converter may be the key to having my Rover V8 engine power matched to the transmission now. I did a test pass last weekend with the new converter and the same old nitrous settings. The launch was, well ! quite exciting to say the least :)

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Perry, Looks like it is time for wheelie bars!

Looked like you peddled it a bit. The crowd always loves it when the front end reaches for the sky. :) Don't beak anything, though.

You Big Game hunter, you!

All I can say Perry is WOW!
Your little MGB has got it "goin on"
I know it goes against everything proper and right. But have you thought about moving the driver to the left side?
On every launch that I have seen, your car is really light on the left. To the point that the right rear tire is having trouble carrying the entire weight of the launch.
This can be tuned out of course, but at a detriment to high speed stability and reaction time, generally.
Moving the driver over is cheap, and costs nothing in power.
Just a thought.
And again "go get em man" I'm thoroughly impressed!

Live like you mean it.
Fred

Thanks for the comments guys!
That launch took me by surprise I must say. I backed right off until the car had got back on 4 wheels and then put my foot back in again. Bit I had been off the pedal for 1-2 seconds I think. I'm more than happy that this would no doubt have been my sub 9.5 pass for sure :)

I'm going to take a little time out to re think things now. I have wheelie bar parts in the garage. I know that I now need to back off the nitrous onnthe launch as well.

I do need to do some checks on the suspension and the landing was quite hard and I can see some slight damage underneath. But thats drag racing eh?

I'll figure out all the problems I have now developed with this new found power and then I'll be back out gunning for my 9.0 pass :)

Perry