1973 Rebuild

[Zed Head]

I think that madkaw has gleaned your objective.  You're trying to replace the hydraulic (oil) pivots with solid.  Therefore, working with a P90 head.  I thought you had a P79.  Regardless, the common method involves timesert thread replacements.  "timesert p90 hydraulic pivot" should pull somersetting up.  Or lifter in place of pivot.  There's a proven method.

[Zed Head]

Here's an entertaining one from old Big Phil.

https://www.youtube.com/watch?v=Gnn84tyeWSc

 

[Matthew Abate]

No, I have two p90as that came with hydraulics and one p90 that came with solid/mechanicals. Four of my mechanical rocker pivots (lifters/tappets) are rounded from being seized to the cylinder head and I want to replace the rocker pivot bushing on those before I reinstall them so they are torqued correctly.

When it comes to the ZX heads, I have read and watched all of this stuff. I know what goes in what and what's compatible and not compatible with what and how to swap the hydraulics for mechanical/solids. I was trying to find the part number to make sure that the parts Courtesy Nissan has listed as "lifters" are in fact what I need, and it seems they aren't, but I'm going to call them anyway.

In the mean time I need to find another source. I found a couple of n47 heads for under $30 so I might grab those. Looking locally first.

[Zed Head]

I see, clear now.  You might try cleaning up the corners and torquing them in damaged just to see.  33-40 ft-lbs is the number which really isn't huge.  They might be fine except for the ugliness.

[madkaw]

You have too many heads- .
I'll take any left over p90a - you want to get rid of


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[Matthew Abate]

You have too many heads- .
I'll take any left over p90a - you want to get rid of [emoji4]


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Once I have a running motor I will let you know. I'm waiting for the numbers to come back from the machinist and for this conversation with Isky to happen before we move forward with one.

In other news, I just got off the phone with Courtesy and they confirmed that the rocker pivot they have is just the skinny pivot itself and not the entire assembly. When I mentioned that I'll try to get some from a junk yard they suggested finding a machine shops that might replicate them. Not sure if it's worth the effort, but I know of one so I might ask.

[Matthew Abate]

UPDATE:

We talked to Ron Iskendarian this afternoon and had a really good talk.
- Told him we wanted to stay under .460-inch lift at the valve so that we could use the stock springs, but that we were willing to do the extra work needed if a cam wasn't available.
- Let him know we were after a really strong low-end and mid range, and that I didn't want to worry about bogging down off the line in traffic; that I wouldn't be tracking the car but would be in hilly terain on two-lane highways and wanted "spirited" performance; that durring long distance traveling I would be on the freeway.
- Told him we were looking for a mild performance hydraulic cam if we could get one but had not found one yet, and that if need be we would use a mechanical but still wanted to stay under .460-inch lift.
- Asked for a suggested camshaft to fit our build.

Also talked about the build in general, letting him know we were increasing compression and freshening up the top end; that we would use the SU carbs. If we needed more carburetion because of the cam, then I would look at tripple Mikunies on the Harada manifold, suplemented with a good header and free flowing exhaust.

He asked about the condition of the cams we have and suggested that, even though I thought they were trashed, he might be able to clean them up. The Hydraulics will be harder to re-grind (he didn't say why) but I might be able to have hydraulic lifters after all.

In fact, he suggested using one of the stock cams unless they were all wasted. He thinks that with the increased compression and displacement in the L28, the car will act wonderfully for my purposes with either the mechanical or hydraulic cam. But once he looks at them, he might also be able to regrind the cams to give me a more agressive profile. Depends on the condition of the cams.

Cost wise, he told me that it would be more important to make certain the cam towers were in the best condition possible, to prevent variations in the cam timing. That is something I have Our machinist looking into.

Ron mentioned, also, that its important to use the stock rockers with any cam because its the rocker that's harder than the cam - even the original Datsun camshaft - and the stock Datsun rockers give the best performance with the least wear to the cam/rocker surfaces, regardless of the cam I buy. He was glad to hear that I bought new rockers from Nissan.

So...
Soon, probably before week's end, I'll send all three cams to Isky, addressed to Ron, himself. He told us to address the package to him personally so he could handle the evaluation, then get back to me.

I imagine turnaround will be about three weeks.

[madkaw]

Drivability will not be an issue with a performance cam. Go with as much performance as you want. Go 490 lift !!
My point is don't limit the cam size based on what you think will be street friendly . My 490 /290 idles at 750rpm and pulls around town in 5th gear at 1500rpm just fine.
If looking to keep stock springs and valve guide seals , then that's a different story . Sounds like you caught Ron on a good day, but I have seen 2 times that he sent the wrong cam card with the cam. Not much support after the purchase also.
Stock cam regrinds are common and best . I would make sure I go with an internally oiled cam .


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[Diseazd]

24 minutes ago, madkaw said:

Drivability will not be an issue with a performance cam. Go with as much performance as you want. Go 490 lift !!
My point is don't limit the cam size based on what you think will be street friendly . My 490 /290 idles at 750rpm and pulls around town in 5th gear at 1500rpm just fine.
If looking to keep stock springs and valve guide seals , then that's a different story . Sounds like you caught Ron on a good day, but I have seen 2 times that he sent the wrong cam card with the cam. Not much support after the purchase also.
Stock cam regrinds are common and best . I would make sure I go with an internally oiled cam .


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I couldn't agree more......Isky Stage III (.490 lift) is no problem for the street......or with SU's. You'll love it! You do need a performance spring so they don't stack, but Rebella sells an outer spring that can be used with your stock inner spring and retainers for about $100.00. You'll need to geometry the rockers with thicker lash pads regardless of a .460 or .490 used.

[Matthew Abate]

Madkaw, what's your power and look like? Where does your car really start to pull?

Diseazd, I think we'll end up sending him a cam to regrind based on that conversation, so it'll be internally oiled.


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[Diseazd]

Matthew......My L28's with the shaved P79 heads and Isky Stage III cams build about 170 h.p. To the wheels (200 to the flywheel), with SU carbs. They pull hard through all rpm ranges.

[Matthew Abate]

I was talking to a paint shop this morning and they asked me how the factory did the underside of the car. Am I right that it was primer, then undercoat, and then they DID NOT paint the underside in the body color? It should just be oversprayed, right?

Does this extend to the wheel wells, too?


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