A14 valve springs for stock rebuild

[femtnmax]

Hey out there....I'm new to this forum... I worked as a Datsun factory trained mechanic back in the 70's. They are great cars/trucks.

Right now busy rebuilding the drivetrain on a 1979 210 2dr with a beautiful body:) I'm setting the engine up with MPG cylinder head, compression is 10.0 with pistons flush with block deck, thinking of doing some head milling and going for 10.3:1. (set up my 74 B210 with 10:1 and .045 quench & get 49 mpg tops with 4speed). For the 210 have finished a 5spd trany, took 2 years to find the parts w/o paying excessive. Cannot find the 3.54 rear axle ratio, so will live with the 3.7 ratio.

The problem: valve springs are tired with 150,000 miles on the speedo. The lifters have been chattering off the tops of the cam lobes which has damaged most of the lobes. Cam/lifters need reground/resurfaced.

Found a A14 cam in the local parts yard off a 78 F10 with only 106K miles, but the cam lobes are starting to show the same problem. Maybe its the EPA oil being sold these days which is not good for flat tappet cams.

 

Where can the cam be reground to stock specs, can anyone recommend a cam grinder? I want a good job done, not quick and sloppy. Cam is the 248/256 seat duration dual pattern.

Anyone found replacement valve springs? I've searching thru several sources... I'm finding some possibilities with Sealed Power but not all the specs are listed so not completely sure they will work correctly.

Thanks for your help.

[RedBanner]

I havnt looked for new springs, I was fortunate to find new complete heads on several occations.

I am interested in wich pistons you used?

[femtnmax]

Pistons: I found some A15? pistons on ebay. My understanding is they reduced the piston dish in 1981-82? when they changed the cylinder head to the "deep" combustion chamber. The pistons I found are 0.20 inch overbore with shallow dish (4cc). With this combo it was easy to reach 10:1 static compression when using the quench combustion chamber; only milled the heads 0.008 inch so far to make them flat.

On the A12 thats in my 74 B210 the pistons had a much deeper dish. I had to deck the block for pistons 0.005 out of the block and mill the crap out of the head to reach 10:1. Head gaskets are coming out at around 0.05 inch thick.

More research today:

Cam grinding....Elgin Cams and Delta Cams both regrind cams. Elgin lists alot more lift, great for performance but not so good for long life. I'll phone Delta and see what profiles they offer.

Valve springs...Isky cams lists a dual spring for A-series Datsun. I'll be calling them, hope they still sell them.

[RedBanner]

They should all be dual spring, in my experiance they have ben.

[ggzilla]

Isky is good for HIGH rpm and high guide wear. Nissan still sell the stock springs, for up to 6000 rpm. Finally the factory twin springs are good for 7,000, sometimes higher.

 

A15 with the factory cam grind? Why not have isky grind you up a more modern, less emission grind?

[femtnmax]

What are the spring rates for the factory dual spring?

 

For my A14 the factory spec is 49-56 lb at 1.524 inch valve closed, and 120-138 lb at 1.189 inch valve open.

I bought a set of OEM Nissan springs, part # 13203-H1000. Both seat and open pressures were below the minimum spec in the factory service manual. Adding a 0.030 inch shim brought the seat spec up to 56 lb, the factory max, and 124 lb at valve open which is at the low end of the factory spec. With the .03 shim at max valve lift there was only 0.060 clearance to coil bind, so I would not add any more shim.

The Isky springs checked out with 80 lb seat pressure, and 150 lb open. The seat pressure is high, but the open pressure is only 12 lb over the factory max.

 

I can imagine the stiffer springs would wear the old style brass valve guides. Does anyone have experience with the newer steel guides that are in the 1979-1980 heads I'm working with. I would think the newer guides would hold up better. The head I'm working with has 140,000 miles on it, and all the valves had very little valve stem wear. Only the exhaust guides were worn enough to need replaced. So the factory valve springs are easy on the valve train, but become weak enough to cause cam lobe damage over time.

 

The engine is an A14 with dual pattern cam. I'm building for fuel economy and want it to run over 100k miles without issue. So I wasn't thinking of adding much performance beyond a compression increase to 10:1. I know, the wimpy valve lift at .335 inch is not much to talk about, but it appears to be easy on the parts.

 

I have a 1989 Nissan Sentra with the GA1.6L 12 valve engine. That engine will run circles around the A14. I've toyed with the idea of putting the GA1.6 into the old 210, but havent worked thru the fit issues... That Sentra has 320,000 miles on it...its like just getting broke in...45-56 mpg and torque/power to really get around. The 56 mpg was a one time deal had a real good tank of gas, filled up at the Wyoming oil fields, you could just feel the power. 45-50 mpg is typical, not bad for an old beater. The fuel economy calcs are using highway marker miles, not the speedo, so no...I"m not cheating the numbers.

[datzenmike]

I could be wrong but valve spring pressure is felt on the valve seat when closed. The valve exerts this load longitudinally along the valve length, not sideways against the guides. I'm sure there is some slight side loading but it should be the same for any stiffness of valve spring.

 

Also not clear what your goal is here as you are running over 10 compression, stiffer springs for revving, and more cam yet are looking for a 3.54 ratio rear end??? I would think a 3.889 or even higher would make better use of the revs.

[ggzilla]

Unfortunately the spring pressure is at an angle on wedge heads like the A-series.

By contrast The OHC use cam followers so is more gentile. Yes, it wears sideways on the guides when the rockers push it down and a little sideways 3,000 times a minute.

 

I didn't realize the later heads had different guides. I know the earlier guides are the first things to wear out, long before the rings start to wear.

 

The isky springs are good for 8500 rpm (i think), factory twin springs good for 6,600 rpm, and stock for 6,000. So the factory twins are not very radical. The stock units will usually go to 7,000 but not guaranteed. Blueprinting as you are doing (to factory spec) is a very good idea. If the valve seats have been ground more than once shims are usually needed.

 

I'm building for fuel economy

Well then you certainly don't need dual springs. The MPG heads don't make any more power above 6000 RPM than they do below -- even with more cam & carb. Keeping the revs low is the fastest way to high fuel economy. You can easily get 50 mpg @ 55 mph with 3.7 gears and A14 with 5-speed.

 

GA16E has been done. Ditch the distributor and use MegaSquirt to do the spark and injection. GA16 will bolt to the B210 5-speed with most of the bolts lining up. The B210 5-speed is the only one strong enough.

[femtnmax]

Also not clear what your goal is here as you are running over 10 compression, stiffer springs for revving, and more cam yet are looking for a 3.54 ratio rear end???

I'm only looking for improved cam lobe life. All three A14 used cams I have are showing damage to the downslope off the lobe peaks, and some chattering on the upslope on some lobes...I assume its from lack of enough spring pressure because I tested all the springs and the higher mileage springs showed the worse cam lobe damage, along with progressively weaker valve spring pressure.

Sounds like I should go with shimmed OEM springs. Thanks for the feedback.

 

As you say GGZ, for the little MPG intake ports I wasn't sure more valve lift would help. I'm sure a better lobe profile would help performance, but the car is for my wife, and she hates it when I soup things up too much. She used to have a 396 SS chevelle, and it scared the BG's out of her...now she's gun shy.

So your saying the GA16 engine would bolt to a dog-leg B210 5 speed?? I have a 89 Sentra parts car w/ engine, a B210 sedan that needs engine OH, and a dogleg 5 spd under the bench. Sounds tempting.

[ggzilla]

That's what they tell me. I haven't seen it in person though.

 

 

The keys to cam life are two:

 

1. When installing new cam & lifters, use cam lube and immediately upon starting run it at 2000 rpm for 20 minutes. Do NOT let it idle.

 

2. Use 10W-30 (not 10W-40 or 20W-50) and change it regularly, every 5000 miles for 5 months.