well the Cummins motors they put in the 1 ton Dodge pickup trucks, had a mechanical injection untill around '97, one of my buddy's had one, we just cranked up the injector pump, and the thing ran like a raped ape!....for a diesel anyways! yea, I know it's alot of plumbing, I would only go that route for the coolness of it all.....mechinacal injection.....old school......sounds like fun!
motor questions
- Thread starter ckouba
- Start date
I admit I am not an engine/induction expert (which is one reason I read this forum!!!!! TO LEARN!!!) Anyways on the topic of mech injection... Jim (J6) in one of his awesome threads about the "rebirth" of a P4 said the following,
"They are pretty close sizewise but the P4 is a little smaller and a lot lighter. It's a touch lower as well.
They're quite different. The MK-IV has much more low end torque but the P4 feels faster through the turns. On the street the P4's mechanical FI takes some heal and toe to keep from stalling and it's sequential gear box, you have to go 3,2,1 to get 1 takes remembering. The MK-IV will pull away from a stop in almost any gear but under 4K the P4 makes little torque.
Best"
And he is a very fortunate gentleman to have a lot of seat time in beautiful cars.
Based on that, I would either choose EFI or carbs, not mech inj.
As for motors.. It seems to me that the general consenus here is that for the weight of a '40 that a mild/medium crate motor is more than enough for general road use and motor like Sandy's is.....well kinda like taking a bazooka to a knife fight!
(BTW Sandy... I LOVE IT!!!!)rockonsmile When I finally get the chance to build one (DARN YOU FRAN) I will prob. be in between (w/ webers
)
"They are pretty close sizewise but the P4 is a little smaller and a lot lighter. It's a touch lower as well.
They're quite different. The MK-IV has much more low end torque but the P4 feels faster through the turns. On the street the P4's mechanical FI takes some heal and toe to keep from stalling and it's sequential gear box, you have to go 3,2,1 to get 1 takes remembering. The MK-IV will pull away from a stop in almost any gear but under 4K the P4 makes little torque.
Best"
And he is a very fortunate gentleman to have a lot of seat time in beautiful cars.
Based on that, I would either choose EFI or carbs, not mech inj.
As for motors.. It seems to me that the general consenus here is that for the weight of a '40 that a mild/medium crate motor is more than enough for general road use and motor like Sandy's is.....well kinda like taking a bazooka to a knife fight!
(BTW Sandy... I LOVE IT!!!!)rockonsmile When I finally get the chance to build one (DARN YOU FRAN) I will prob. be in between (w/ webers
)
Howard Jones
Supporter
Here's my advice. If you buy a crate motor take it apart and rebalance the rotating assembly to your flywheel and clutch of choice. Even if you use the 5.0 flywheel that comes with the crate motor, rebalance it (the whole thing) anyway. This will be the best 500 dollars, or so, you ever spent.
You can make measurements of all the bearing clearances and ring gaps etc. and when you are done you will KNOW exactly what you have. If you do this right away you can reuse all the rings and bearings, assuming all the specs are correct and you are careful when you take it apart.
Crate motors are a good way to get a complete set of all new parts. Much less money than buying everthing piece by piece. Also with all new parts you won't need to replace anything such as worn pistons or cracked heads, block etc. as you reassemble it. All you will need is a gasket set.
You can make measurements of all the bearing clearances and ring gaps etc. and when you are done you will KNOW exactly what you have. If you do this right away you can reuse all the rings and bearings, assuming all the specs are correct and you are careful when you take it apart.
Crate motors are a good way to get a complete set of all new parts. Much less money than buying everthing piece by piece. Also with all new parts you won't need to replace anything such as worn pistons or cracked heads, block etc. as you reassemble it. All you will need is a gasket set.
Jim Rosenthal
Supporter
Mechanical FI versus EFI w/ EMS.....in the sixties and seventies Mercedes probably had more experience with MFI than any other manufacturer. I have had several older MBs with Bosch FI. For their time, they run very well and hold their tune very well...but times have changed.
You can get some idea of this by looking at the website of Karl Middelhauve, who is the Mercedes M100 guru and the original German looney tuner. (www.mbgrand600.com)The M100 V8 is the SOHC engine that powered the 600, 6.3, and 6.9. Very underrated at 300hp and made huge torque. Karl has built several of these engines which he converted to EFI. Even as good as the OEM Bosch system was, the difference is night and day. Incredible gains in hp, economy, driveability. Definitely the way to go. He has also devised modern EFI systems for vintage Mercedes V8s which had early Bosch Jetronic EFI, and reports great improvements in performance, economy, and driveability with those engines as well (3.5, 5.0, V8s)
Bottom line? you can't beat an intelligent engine management system, honestly. I will get my GT40 running, and work out the bugs in the chassis and electricals, and then think about an EFI system. The MassFlo system has some intuitive pluses- if you are actually measuring the air going through, you have better data to figure the fuel requirement. And a hot-wire sensor adds no obstruction to flow at all.
Oh, and FWIW, the new crop of marine diesels and truck diesels are all common-rail high pressure electronics as well- they've given up mechanical FI as well. That's a little different to me, though- if the engine quits out there you can't call AAA to come get you.
You can get some idea of this by looking at the website of Karl Middelhauve, who is the Mercedes M100 guru and the original German looney tuner. (www.mbgrand600.com)The M100 V8 is the SOHC engine that powered the 600, 6.3, and 6.9. Very underrated at 300hp and made huge torque. Karl has built several of these engines which he converted to EFI. Even as good as the OEM Bosch system was, the difference is night and day. Incredible gains in hp, economy, driveability. Definitely the way to go. He has also devised modern EFI systems for vintage Mercedes V8s which had early Bosch Jetronic EFI, and reports great improvements in performance, economy, and driveability with those engines as well (3.5, 5.0, V8s)
Bottom line? you can't beat an intelligent engine management system, honestly. I will get my GT40 running, and work out the bugs in the chassis and electricals, and then think about an EFI system. The MassFlo system has some intuitive pluses- if you are actually measuring the air going through, you have better data to figure the fuel requirement. And a hot-wire sensor adds no obstruction to flow at all.
Oh, and FWIW, the new crop of marine diesels and truck diesels are all common-rail high pressure electronics as well- they've given up mechanical FI as well. That's a little different to me, though- if the engine quits out there you can't call AAA to come get you.
The original Lotus 47GTs used a Lucas (The Prince of Darkness) mechanical injection set up. After the inital successful outing, the cars seemed not to finish, and I believe the team switched to Webers. I think I'd shy away from a Lucas system simply from a reliability standpoint. I think the best advice you've gotten is to go with a 4bbl until the car is sorted out, then play with the induction/carbs.LedheadELH said:
John
Jim Rosenthal
Supporter
I neglected to mention that my 302 SBF was assembled and dynoed with a Holley 4bbl and made 360 hp. That is enough to push a GT40 as fast as I want to go while I am sorting it out. Time enough for EFI later on, once the bugs are worked out.
EFI ? Are there no MEN left anymore ? Here it is... 4 Webers , long connecting rods , high compression and lots of lift and duration...works every time.
I like to get my hands dirty and mechanical systems are the bomb. The 26 million dollar jet I work on all week just dosen't do it for me anymore. To much electronics keyboard fondling. As I get older I find I need to constantly smell 100LL or race gas burning, mixed with a little engine oil and sweat. Thats why I need Webers.
Similar threads
