I sent an email to British Car Conversions, got a reply from Bill Sinclair. Have a feeling he was also Killer B. His replies were minimal. I also found an email(from 2010) from someone(no company info) regarding the ECU changes. Sent them an email but no response yet. Digging further into the random left over bits box I found a manual from Advance Auto Wire for a complete MGB V8 conversion wiring harness. The car was completely rewired which makes me very happy.
This is not my first incomplete or abandoned project car, so I tend to do lots of research before digging in and doing something. This one is the best of these cars, all I had to do is put in a battery and fuel to get it running. The workmanship on the wiring is excellent, better than I could do. Thanks to all for your input.
Crank sensor is aftermarket. Can anyone id the engine size from this head shot?
wvumtnbkr said:
The cam sensors are all the same and in the same location as far as I can tell. I know they are on the la1, lx9, and lz9.
According to the people on msextra, there are two different cam sensor wheels/moons. Not sure where the year split is.
porschenut said:
Crank sensor is aftermarket. Can anyone id the engine size from this head shot?
That's a GM crank sensor, and it looks like there is a "7X" wheel (6 teeth, plus one) cut in to the damper. This would allow an old style ignition module to work. (Which I see against the firewall behind the intake manifold)
On that system, the ignition module read the 7X signal and IT controlled the timing and which coil to fire. The ignition module sent a signal to the engine computer for RPM/injection timing reasons, basically a generated distributor pickup signal. The computer sent a signal to the ignition module to tell it how much timing to run. I forget if it was PWM or what, but if you disconnect that signal from the ECM the engine will still run, just at base timing. The ignition module does all the heavy lifting.
This, again, was GM making distributorless ignition work with a computer designed around making a distributor work. 1980s kludging at its finest. (It did work rather well)
This makes me think you have an old GM ECM like a '730. That is the computer you'd find on an old front drive 2.8. It's thoroughly hacked and not a bad platform if you have a PROM burner.
As to your other question. The 7X wheel is normally part of the crankshaft, in the middle of the engine. If they had to add an external one, it is probably NOT an early engine.
I would think that one couldn't ID the engine size just from that head because all of the aluminum heads look kind of like that. But it is probably not a 3100 or 3400 because those had the 7X wheel internally.
The only difference between a 3900 and 3500 (second series) is the stroke. The first series 3500 was a big 3400, they opened up the deck for the 3900 to make room for larger bores, and the second series 3500 is a destroked 3900. Very large bore and short stroke.
I'm a pedant about nomenclature because there is a big difference between a 3.1/3.4 and a 3100/3400. Iron heads vs aluminum, and I think even the blocks were significantly different.
I tend to believe the PO on this, he did say it was a 3.9 from a G6 GTP. Never got an answer on the cam question though.
In reply to porschenut :
I haven't responded to your question, because the easy answer is the intake manifold. That is obviously a 3500 intake. But, they are swappable, so?
I believe my engine has a 3.9 cast into the block. Let me see if I can find a picture of it and where it is located.
Actually, I did find a pic. My block has both 3.5 and 3.9 cast into it.
This is on the passenger side under the head near the front of the block.
In reply to wvumtnbkr :
Just looked at the Rock auto parts pics, the 3.5 has exhaust studs in a vertical line. Mine are not.
In reply to porschenut :
That is true of the first series 3500. The second series 3500 shares exhaust manifolds with the 3900.
In reply to Pete. (l33t FS) :
Oh well, still think it is a 3.9 but this is my first V6.
I don't think it really matters as long as it's already spooky fast. At the end of the day you've got a late VVT GM 60 degree V6 that has had a fixed cam installed, been converted to OBD1 with a 7730 ECM, and it's been shoehorned into an MGB with a lot of well done craftsmanship and Quality Parts. Enjoy it for what it is. If there's no problems with it don't go hunting them
In reply to Dusterbd13-michael :
And tell people it's a 2.8 
Well it is a 3.9 but the valvetrain noise has me concerned. I changed the oil, no metal signs and new 10W30 had no effect. The noise seems to be loudest under the intake. Need to find out if there are any typical screwups when eliminating the VVT system. But in the meantime the turn signal switch died and there are a few small things to address. Oh, also found the tires have a 2011 date code so that got moved up to the top!
tires are here, spending some time polishing the rims before they get mounted. Also have a coolant leak, the rubber ends of all hoses will be replaced. But stuck on valvetrain noise. Want to check the preload on the lifters but have no idea what they should be. I am betting it is the stock cam with the VVT removed, stock rollers too, I would think get a cylinder to TDC, back off the adjuster then get the slop out and tighten, but how much? Half turn, full turn? Anyone have a clue?
porschenut said:
tires are here, spending some time polishing the rims before they get mounted. Also have a coolant leak, the rubber ends of all hoses will be replaced. But stuck on valvetrain noise. Want to check the preload on the lifters but have no idea what they should be. I am betting it is the stock cam with the VVT removed, stock rollers too, I would think get a cylinder to TDC, back off the adjuster then get the slop out and tighten, but how much? Half turn, full turn? Anyone have a clue?
There is no adjustment. You just tighten down the bolts to torque.
I'm thinking exhaust manifold leak. Sounds just like a lifter tick on these engines in my experience.
In reply to wvumtnbkr :
Well one cyl checked shows 012 intake, 017 exhaust
In reply to Pete. (l33t FS) :
lash, as in pushrod to rocker. Rocker pivots, alot more on some. Is there a shim to adjust?
I checked the rocker bolt, was tight. Checked a few more, all are the same numbers or more.
They should be preloaded, not have lash. Although, if the engine has not run in a while, you may be able to easily push the piston down in the lifter, making it feel like lash.
I am making the grand assumption that it has hydraulic lifters. I'm not sure that anyone even makes a solid for this engine.
There is no adjustment at all, you bolt the rocker down and that's that. At least, that's the way Chevy made it.
No this is real lash like an air cooled vw but no way to adjust. I suspect it sat for many years and something is up with oil pressure. The gage shows 30 regardless of rpms, fresh synthetic and new filter. It may be time to get a pontiac G6 manual so I have some info on the engine.
porschenut said:
No this is real lash like an air cooled vw but no way to adjust. I suspect it sat for many years and something is up with oil pressure. The gage shows 30 regardless of rpms, fresh synthetic and new filter. It may be time to get a pontiac G6 manual so I have some info on the engine.
If you have lash, you either have too short pushrods, or not pumped up lifters. Or short valves.
Either way, if you have run it for 5 mins and it didn't Clear up, I would be checking for bent pushods or collapsed lifters.
The lifters may be gummed up and stuck down if the engine hasn't run for a while. Running it may help but you may have to pull the lower intake so you can remove them and soak them in solvent.
It has more than 5 minutes but not by much. Will try some seafoam and an hour of driving. I do think it is getting better so hopefully some run time will help. Have been keeping the revs and speed down, tires were 2010 date code. New ones go on monday.
