A Texas 320

[difrangia]

2 hours ago, Stoffregen Motorsports said:

Since I am a British car owner once again, I have been thinking about the parts interchangeability between these motors and BMC motors. I wonder if one of the aluminum MGB heads would bolt up to this block. They make the aluminum heads in crossflow too.

 

Dammit, Matt, now ya went and burned up a couple hours of my weekend time tieing me up on the net searching knowledge on the crossflow heads. 

 

What I've seen initially is that the MSX Crossflow head for the British motor is marked by Pierce Manifolds who many on this forum are quite aware of. Seems the heads are manufactured by PBS Engineering in Garden Grove CA. I became acquainted with Paul B. Swenson (PBS) about twenty five years ago when I started building a modified engine for our 1961 FIAT 500D. I believe that Paul has now passed on, but a lengthly phone conversation in the early 90's resulted in one of my FIAT 500 cams getting shipped to California for a reprofiling for $25 and a pair of 40 HP Volkswagen cylinders receiving extensive machining to fit into the FIAT two-cylinder engine resulting in 650cc. I could now kick my own ass for not gathering all my 500 cams up and having them done at the time. PBS was heavy into FIAT racing in the 70's - 90's and were Highly respected in the culture. The trinkets manufactured/modified by PBS are highly sought after now. They were also into Whizzer motorbikes back in the day.

 

Not trying to hijack the thread but your mention of the crossflow heads got me going. 

 

Steve

[jetattblue]

No problem at all. I think any 320 discussion is helpful!

[Stoffregen Motorsports]

Always trying to push the envelope. Developing vintage cars and trucks in a way that actually improves on them is a way of life. And it provides me a steady income...

[jetattblue]

Quick question about rocker assemblies. As part of my engine tear down, I removed the rocker assembly last night and started cleaning it up. When I removed the pedestals and rockers from the shaft, I noticed that the rocker shaft was badly scored in many places. I'm going to inspect the rocker bushings today and see what kind of condition they are in. Assuming that I need to replace some of these parts: is there a replacement for the rocker shaft - perhaps one from an MGB? Also, where should I get the bushings for the rockers? Thank you. 

[Charlie69]

A good head rebuild shop should be able to recondition or replace as needed during head rebuild.

[jetattblue]

Here's a quick update and question for you all.

 

First, the cylinder head has been sent to a machine shop. They found no issues with magnaflux. But, the valve seats were pitted, so the shop is going to rectify them.

 

Second, I am SO close to having the engine taken down to the block. I am doing this so that I can send it to the machine shop, too. The tappets and cam shaft are the only things remaining in the block. Does anyone have any advice on removing the cam shaft? I keep reading to pull it out and turn as you go, but I cannot figure out how to grab it to pull it out. Any helpful hints? I have the same issue with the tappets; I want to grab them, but I don't want to mar them in the process.

 

I also hope to have some pictures to update here very soon.

[Stoffregen Motorsports]

I haven't had a stock 320 motor apart before, so I don't know exactly what the cam situation looks like. If the engine block has lifter covers in the side of the block, then this means they probably come out the top. If it doesn't, they may come out they may have a wide foot at the base, which means that they can't come out the top.

 

To pull the cam, just install the gear back on it and use it to gently wiggle it out of the block.

 

Once you get the cam out, then the lifters come out. Keep track of their exact location, because if they are in good shape (and the cam is too), then they need to go back onto the same cam lobe they were on before. You can use a piece of cardboard with holes punched in it to store the lifters out of the block.

 

Maybe this link will help - http://www.mossmotoring.com/disassembling-british-engine/

 

Beware that not every machine shop is good at oddball engines. I need to trust a shop before I give them my unique engine parts to work on. That said, inspect everything as it comes apart. If the cam bearings, lifters and cam surfaces look good, leave them alone and re-use them.

 

 

 

 

[difrangia]

Side covers off first. Lifters lifted straight up and out of their bores second. Drive shaft for the distributor out second or third ( there's a tapped hole in the top of the driveshaft, 5/16 - 18 NC if I remember correctly but maybe 5/16/ - 24 NF possibly). Screw a longer bolt down into the distributor driveshaft and pull it out the opposite side of the block as the cam. If I remember correctly there is a plate with a spud that goes down into the block under the distributor that is secured with a flathead screw or two to the side of the block where it is machined for the distributor between the distributor and the block that must be removed before the driveshaft will come out. The spud goes down in the distributor driveshaft bore and holds the dirveshaft down. I'm thinking that you may need to remove the oil pump also.Then the cam should slide out. You can use the camshaft drive gear to pull the cam as Matt said.

 

Refer to the factory shop manual that can be accessed at this link:

 

https://nicoclub.com/FSM/Datsun 320 Factory Service Manual.pdf

 

The tappet removal is on page 38 and the distributor removal is on page 45 (page numbers are PDF page numbers and not the shop manual page numbers).

[jetattblue]

Thank you for the info! I've got everything out except the tappets and camshaft. I'm going to try them both again tonight and see if I can get them all out.

[difrangia]

Tappets will lift straight up and out the left side if the heads are not mushroomed. After the tappets, oil pump, & distributor drive shaft are out the cam will pull straight out the front after the cam retainer plate is removed.

 

When I rebuilt Mighty Mouse, I had the cam reground with same basic profile and .050 more lift added. I had a couple of cams done at a shop in Oklahoma City, one for me and one for Andy up in Kansas. Also had a couple sets of lifters refaced. Learned a bit in the process. The lobes are not perfectly parallel to the camshaft axis, but infinitesimally out of parallel. Also the lifters are very slightly dished. This causes the lifters to rotate slightly when the engine is running so they will wear evenly and not develop abnormal wear patterns. My dad was a Chevy dealer mechanic and it always fascinated me to see a Chevy running with the valve cover off and see the pushrods rotating.

 

Something else that I would recommend, at least during break-in period is using an oil that is high in ZDDP or adding a little ZDDP addative to the oil. I use Rotella-T diesel oil in most all of my old flat-tappet vehicles and I believe that it has a decent level of ZDDP. I'd have to look, but I believe that I used Rislone ZDDP addative till first oil change. Good chance that it's probably gonna start a discussion, but ZDDP has been gradually removed from most motor oils due to emission regulations and the changing structure of engine design. Roller cam followers and low friction materials have reduced the need for the lubrication qualities that the ZDDP provides. These old engines still have half a century old engineering and materials.

Edited July 30, 2019 by difrangia

[jetattblue]

Steve, that's excellent information as usual! What does the .050" of added lift do? I'd be interested in knowing if that helps out somehow. I really don't know anything about different grinds or shapes on the cam shaft.

 

My cam shaft is entirely disconnected, but I was not sure if it just slides out or if it requires significant force. It feels pretty tight in there to me, and I certainly don't want to break anything.

[difrangia]

I personally can't attest to the change that the extra lift made. The original E1 (number matches cowl tag) was pretty much worn out (replaced the crank as it was well worn and would run for 15-20 seconds before oil pressure would pick up enough to extinguish light so I didn't drive too briskly for the year that I drove it while I was gathering rebuild parts) and was column shift. I also changed the carbueration to Weber 32/36, bored cylinders .060 over, and changed transmission to floor shift. At the same time I replaced all the shocks and changed to dual circuit with front discs, so the driving experience is much better.

 

The lobe profiles were kept pretty much the same except for the extra lift and the overlap and duration were not changed. The cams were re-parkerized also. Andy has bout half dozen 320''s and says the cam made a pretty noticable difference in performance in the one he put it in and also compared to his other pickups.

Edited July 31, 2019 by difrangia