'51 GMC,4200 Vortec DOHC - Turbocharged

[seanm]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Cool project. Is this the same type engine that was in that blue Nova wagon that ran on Dragweek and the pump gas drags a few years ago. Not trying to start the controversy about the wagon owner, just wanting to know if this is the same engine.

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Cool project. Is this the same type engine that was in that blue Nova wagon that ran on Dragweek and the pump gas drags a few years ago. Not trying to start the controversy about the wagon owner, just wanting to know if this is the same engine.

Yes it is.

[seanm]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Thanks. Thought that combo was trick too. Lots of potential.

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Has a little setback ( and no I didn't move the engine rearward.. ) The freaking oil pump pick seal partially failed, at >3000 rpm when the engine was hot, the pump would cavitate - oil pressure would drop to 0 spike to 80# drop to 0, dropping the rpm 35# oil pressure at 2000. 100 psi cold with 15-40 rotella..


> > > > engine had to come out - its on its way back in now.

[CTX-SLPR]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

How hard is it to set one of these things up to run stock with a MSq? The wife is warming up to the idea of a 67-72 Suburban as a kid hauler with some distiction and this would be a cool and powerful enough powerplant.

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

How hard is it to set one of these things up to run stock with a MSq? The wife is warming up to the idea of a 67-72 Suburban as a kid hauler with some distiction and this would be a cool and powerful enough powerplant.

I have a msq file for a stock engine so that part is covered. The '02 to'06 engine use an oddball 7 notch crank trigger - earlier this year I was able to get MSextra (with help from James) running on it - I haven't been successful in repeating that feat.. otherwise you can install a 36-1 timing wheel/bracket on the front of the balancer. I have made 2 of them and the kinks are worked out of the design. I have to have them made. Email me if you interested.

If you can find a '08 or '09 they use a 60-2 wheel like the late model LS series.

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Well the turbo's on the built engine and does it ever like the added airflow from the cams and ported '06 head!


Stay tuned ...

[milner351]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Thanks for keeping us updated efi - man this engine is impressive.

I think I can answer your question about why this mill didn't find it's way into the camaro --- crash testing.

You'll notice all modern cars engines are being set further and further back, for crash safety - that's really tough to do with a long engine like an inline six.

That's the same reason the mighty 300 ford inline died after 97 - the F150 body that came out in '96 wouldn't accept the long engine and pass crash, so - we got shafted with the 4.2 V6 as the base :'(

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Yeah....

My intake is finally complete..

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Intakes mocked up on the test fit motor... going on the good engine tomorrow, followed by charge air piping.

[milner351]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

NIIIIIICE

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

• Intake install
  
  
  22 hours and counting....
  
  Just 1 small thing after another... :
  
  • the purchased intake flange bolt hole spacing was off had to file fit each hole...
    
    -finish port matching the runners to the flange..
    
    -took the plenum off to de-burr and clean everthing - the top of the runners pulled from welding at the flange - had to figure out how to get them back where they were..
    
    -the purchased intake flange didn't have the full grooves milled in to take the stock GM
  intake gasket - 3 hours trimming the gasket.
  
  -in one of the supplemental fuel injector retainers - the counter bore was off 1/16 ( I don't have a mill) so a square end burr in the die grinder had to do. Very carefully nibbled at it..
  
  -finally got the intake on - go to put the alternator on the adapters ( I knew this was going to be a headache..) it hits the inner fender... big bar move the sheet metal - it doesn't move any more... air hammer with a panel ripper - clang sheetmetals on the floor - then I see the real problem -- the front pivot bushing for the upper control arms interfering - crap .. can't move the alternator, can't move the UCAB... !@#$!@!#$ ^ grind the alternator - a bit better -still not enough.. will try a 3500 alternator on the the 4200 in the morning - local napa has one in stock @#$%@# $200
  
  - the tapped bolt hole in the manifold flange were off just enough to prevent one TB bolt from starting.
  
  - plus 50 more nitty gritty BS items that slow progress down...
  
  /li]

Prototyping is exciting and frustrating at the same time. Once the alternator is in - still have the charge air piping to do at least I have a way forward on that, sure wish I had a TIG here instead of driving 30 miles....

[SpiderGearsMan]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

the 4.2 alternator is huge and takes up insane space

[efi-diy]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

Your right - 150 amp - the 3500 is a 100 amp so hopefully it fits better.

[horsewidower]

Re: '51 GMC,4200 Vortec DOHC - Turbocharged

25 little things always seem to take longer than 1 big thing. Prototyping is satisfying...and a pain in the ass.

Thanks for the updates. Pics soon??