Derek's 308 engine rebuild

I took my distributor apart today. I have the single electronic SM805A distributor and first thing I did is read Adrian's excellent thread on this (seach SM805A.)

The VR sensors were 737 and 752 Ohms and gave a healthy pulse when the shaft was turned. I could also feel the slight magnetic resistance as they pulsed. The rotor bolt was tight and needed some PB Blaster and a few light taps with the impact screwdriver.

Inside the centrifugal advance has a few degrees of play due to the bushes in the advance mechanism being a bit loose. One of the shorter bullet-nosed plungers was stuck in place so not resisting advance at all. I gave it a bit of a push and it did move so the spring inside is probably shot.

Has anyone done a programmable ignition that keeps the original look? I'd prefer to keep the distributor if I can but most systems seem to be crank triggered with coil packs and no distributor.
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Scott, I didn't know Pertronix made a programmable ignition, I thought they were just triggers that relied on the mechanical advance curve. Do you have a link as I couldn't find any mention on their website.

Paul, yes the inner bearings that are oil lubricated are standard. I have the later setup with the sealed outer bearings pushed further out-- thus the effort to find a good or better solution than the old SKF HT51 C4 bearings.

My VR sensor wires' insulation crumbled when removed so if I don't change to a programmable system I'm considering cleaning up the oxide on the wires with some weak acid and coating the wires with liquid electrical tape. Maybe I'll just replacing the complete wires as they are stiff and may be crumbling inside the white sheath.

Does anyone know the bearing numbers for the SM805A? Mine seem ok-- tiny amount of play-- but worth replacing them and the seals while it's apart.
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Thanks Arvid,

I was thinking of using the 6AL-2 along with the BSM distributor cap/rotor from Superformance and machining a new 8-tooth ferrous wheel for the distributor. Maybe the two VR sensors can be run in parallel with the stock 4-tooth wheel? Then the two cylinder banks can be timed separately to compensate for slack in the timing system.

Another option might be using two single cylinder programmable modules to use with the two sensors/coils. Something like the Ultima, Dynatek, or even the nanoEFI once it is ready.

 

Brian, the great thing about thinking aloud and being wrong on here is that people will try to help and the mistakes will be caught (for me and others down the road.)

Has anyone put 4 ferrous "teeth" on the flywheel or damper for magnetic ignition triggering? I was thinking 4 small lugs onto the flywheel (very little space) or machine a thin ring for behind the damper.

 

The body is finally ready to bring home but I first need to get the 2 meter high snow hill in front of the garage I have borrowed to be removed.

I have pretty much decided on an MSD 6AL-2 for the programmable ignition and I'll start with using the two stock VR sensors in parallel with a couple of diodes to stop each sensor's pulses looping through the other. If that doesn't work well I can get an 8 tooth wheel for the distributor or put a 4-tooth wheel on the damper.

I ordered a few hundred viton stem seals because the usual sources had high shipping costs. Let me know if you need some ($16/16 incl. post)
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I checked the oil pressure relief valve spring using a scale and micrometer. I found it easier to use a valve to retain the spring and give a decent surface area to push on. The free length was good, 18kg at 53,5mm, but only 26kg at 42mm. I checked when the plunger passes the "relief" passage and it happens at 50,5mm so checked this pressure and it was 17,2kg which over 2,54cm sq (18mm diameter) gives an opening oil pressure of 6.77kg/cm which is fine. The spring specs are from the 308/328 WSM, nothing in the GT4 manual.

The crank and block are ready for pick up but I'm stuck at home with sick kids and a mountain of snow to move so I'll put the timing cover back together and maybe start on taking apart and cleaning the carbs.
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I got the timing cover back together. Held the oil pump gear with a clamp to torque it to 4.5kgm and found a socket to tap in the bearings. Now I just have to find the gears that drive the cam drive pulleys. I have boxes in two garages and various parts of my basement. Don't forget the thin cup washers under the front bearings (against the inside clips.)
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I found the timing gears and pulled them through the new seals and bearings using some washers and the old nut. Once it was though enough I used a wrist pin bush as a spacer. I don't have a press and my vice was just not wide enough.

I've cleaned the lower belt pulleys and now have them sitting in that mild rust disolver. Has Anyone plated them? I might just soda blast them and paint with rust converter which leaves a protective blue/black finish.

Ordered the .010" rod bearings from Dinos for 254 euros delivered. That made me wince, knowing I could have ground to 5 thou and used the King bearings which are $48 for two 4-cyl sets.
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After a soak and a brush the lower pulleys looked presentable so I'll skip coating them and maybe just clean up a little pitting on the fences with some water paper and paint some high temp black to give some protection.
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Pete, I used two thin coats of high temp enamel and once it is baked hard I don't think it can have any affect on the rubber of the belts. It will wear off and cause a bit of dust but I don't think it is a problem. I could remove it with aircraft stripper if needed-- I recall a thread where someone painted the whole pulley so will ask them. Has anyone else done this?

 

Pick a number and place a bet. I'd pick 60k miles, makes sure the belts and tensioners are good and changed every 5 years, remove the air injection if you can and it's still on, and then enjoy the car and pull the engine for a full rebuild at whatever number you pick. Worst case it will add a few grand to your rebuild. If you will rebuild yourself do it when you have time. If you're going to sell the car soon don't do it at all. Just my two ngwe.

 

Things are happening fast here. Yesterday I picked up the car from the body shop and the bored block as well. If anyone wants to borrow my torque plate, send me a PM.

Enzo did the crank personally and it is now perfect on the mains and today I finished putting the pulleys on the timing case. The heads are also ready so I'll try to pick them up over the weekend (new valves, lined and honed guides, seats cut etc. After a lot of waiting it is now moving a bit faster.
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This morning I filed the end gaps of my Total Seal rings using the bored/honed block to measure them in. A simple and mundane task but has to be done. Most were .014-.017 so I filed the tighter rings up to .016"

What was interesting was sliding a piston down into the bores with the torque plate off. The sleeves are definitely not round and not the same without the torque plate on and you can feel it as you slide the piston in and out and rotate it. Before the re-bore I would have said the torque plate was bordering on the pedantic and perhaps not essential. Now I am a zealot.

 

Last night I cleaned up and insulated the VR sensor wires. First I got all of the crumbling old insulation off and then separated and sealed the wires where they go into the molded white block (I pushed some of the insulation goo into the block between the wires.) Once that insulation was dry I wound up the wires into a tight "dreadlock" strand and insulated them.

The viton seals arrived yesterday and I baked a few at 400F for 3 hours this morning. No noticeable change so I'm sure they are not NBR. They are a dark puke-green colour and have VZR embossed on the side of the rubber.

I ordered an MSD 6AL-2 programmable (6530) and a blaster SS coil and will test it with the original VR sensors in parallel. If I can get that to work with good accuracy (i.e. not too much timing variation at the crank) then I'll skip the crank trigger.
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My rods were all within 4g of each other in total weight which is the range for a letter group but 6.6g from lightest to heaviest small end. Usually on crank-guided rods like these I would match the small ends by grinding off some material next to the pin holes and then match the total weight by removing material next to the rod bolts. I can see some grinding marks from the factory around the ramps to the BE thrust faces which may have been for balance-- no sign of any end to end balancing. Anyone know if it's worth doing the end to end or is this overkill?
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Ron, from the two sensors, do you know how much the crank and cam timing get out of sync and at what rpms?

 

The heads are back and he skimmed 4 thou off to clean up the corrosion from the coolant spread. He sleeved the guides and cut the seats. Today I'm going to lap in the valves but need to buy a suction-cup stick as I can't find mine. After lapping the seats Ill back-cut the inlet valves at 30 degrees just inside the seats.

I checked the inlet manifolds and they are actually quite a good fit to the ports. This photo was the worst one. I'm not doing much porting-- just matching the manifolds and smoothing the ports with an 80 grit roll. Having read how badly these ports flow I figured I can't polish a turd and I don't want to get into welding.
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