grannyknot

Beautiful work.

I wish I had access to that kind of equipment or I would certainly give it a try. Nissan also says to inline hone the cam towers if they are removed and I've never seen anyone do that, I've always had good luck with spinning the cam, taping the towers and tightening the bolts method. People install new cams on old tower bearings all the time, the heads can't be that different from one another, or at least I'm hoping they are not.

I did what Zed Head suggested, flipped the head up side down, filled a large syringe with lamp oil and filled the head oil system, most of it poured straight out tower 3 & 4 . I've put the word out locally to see if any one has a spare set they can sell me. I had a couple of heads that would have been good candidates but they went for pennies on the dollar last fall when I started purging the storage areas.

Check, check and check, all the oil passages are flowing well with brake cleaner and compressed air, made up some new gaskets for the distribution blocks on the spray bar, even polished the cam tower hold down bolts( oil going to the spray bar has to flow around the outside of the those bolts to get where it is going) ATM, all fingers are pointing to the cam towers and too much clearance for the cam bearings.

Yeah, be doing that tomorrow, seems the running clearance between the cam journal and cam tower bearing is: 0.038-0.067 mm, on tower 3, 4 and 5 I have 0.11 mm.

Wow, $30 for 20ft

Definitely a table, make sure you also install the SS trim as well before installing in the hatch.

But it works fine just the same, I had that style of seal on the hatch of my 240z for years and never leaked.

I hoping, last time I did that test it was a dribble. It is kind of a convoluted route the oil has to take to get to the oil spray bar with changes in direction and obstructions. The head is going back on tomorrow so my fingers are crossed. Also figured out the oil pump is the stock variety, not the high volume type.

I've sold a couple of cars on BaT and you do get to review the ad and make changes/additions.

I got the carbs, header and cylinder head off this afternoon, there was some muck in the oil passage just above the oil jet, not sure if it was enough to cause the problem but I'll take anything I can get. I don't believe there is a a blockage in the block anymore considering how free and easy that jet of oil came out in the video, I did it several times to be sure, it even hit the ceiling on one try and never got the drill above 1000 rpm. The cam is new, the cam towers are not, the towers have some wear on the tops of the bearings, didn't have time today start measuring but will tomorrow, it could be I'm losing the pressure on the cam bearings. Do they still make those towers? MVI_2351.MP4

I have 5-6 mechanical pressure gauges but all of them are 1/8th-28BSP instead of 1/8th-27NPT, need to pick one up. I was told that the oil pump is the upgraded high flow variety but I think I should do some measuring while everything is apart, does anyone know what the internal differences are between the stock pump and the high flow? Thanks

Ok, I see what you and Jonbill are saying now, never thought of the low end like that. I did a plastigage test on 3 conrod and 3 crank journals and the gap was bang on so I guess I'm looking at an obstruction in one of the passages. Thanks guys

You're talking about adequate pressure to the cam bearings? I'm not sure I understand how forcing oil through a 1mm dia hole at the top of the block that then opens up to a 6mm hole in the head creates pressure. The oil passages in the 5 cam towers for the cam bearings and oil spray bar are, I believe, 4mm holes. It seems to be the opposite of pressure I know these engines have driven millions of miles in the past 50 years with this system but still can't see a reason for that 1mm restrictor in the middle of the block. I've got to do something, I can't run the engine for more than half a minute the way it is. I'm thinking about ordering one of these, https://www.yoesheadporting.com/product-page/datsun-240z-260z-280z-cam-oiler What is nice about his design is he is using the oil supply from 3 towers for the spray bar instead of 2 the way it came stock.

Bringing this thread back because I'm having the same problems, in my case I know the head and all passages are clean and free of debris, same with the oil spray bar. I even made small gaskets for the cam tower oil ports and put a bead of flexible Motoseal around the wiggly spray bar where it enters the cast aluminum C housing. Any oil that is entering the spray bar is exiting through the 12 holes but as you'll see from the video it's more of a dribble than a jet. The oil was cold when I did that test on the video but even when I was running the engine yesterday and the oil was hot there still wasn't enough oil to lubricate the cam. Where I'm thinking the problem lies is the 2 restricted oil ports in the top of the block, They are tiny and when I was reconditioning the block I didn't want to screw them up so I left them in place but couldn't really be sure those passages were clean. Even if I remove the head again I can't drill those tiny holes bigger without introducing metal filings into the oil passage, I guess I could use an awl and of mash them wider. In fact I'm not even sure why those restricters are there in the first place, in the head the oil bar already has a restricted orifice going in. Any suggestions? MVI_2347.MP4

I sprayed it out with brake cleaner before reassembly but maybe I should hit it with a butane torch to burn off what might be inside. I have to resolder one of the joints anyway because it's loose. Looking at the design of the oil spray bar, the 2 holes that supply all 12 cam holes hardly seem large enough to do the job, wondering a slightly larger supply hole wouldn't up the pressure for the cam holes. Or maybe a thin gasket, the cam tower is machined flat but the face with the supply hole sure isn't. Good point, I might pull the cam just to have a look at the rockers, make sure they weren't damaged, I think I was seconds away from wiping those cam lobes.

I sprayed it out with brake cleaner before reassembly but maybe I should hit it with a butane torch to burn off what might be inside. I have to resolder one of the joints anyway because it's loose. Looking at the design of the oil spray bar, the 2 holes that supply all 12 cam holes hardly seem large enough to do the job, wondering a slightly larger supply hole wouldn't up the pressure for the cam holes. Good point, I might pull the cam just to have a look at the rockers, make sure they weren't damaged, I think I was seconds away from wiping those cam lobes.

Well not quite but the engine did start right up after repositioning the oil pump shaft, it moved the rotor to where it is suppose to be in relation to where it was. So, engine is running, revs are at 1200-1400rpm, the synchrometer is read about 7kg/hr on all horns, the distributor is turned all the way to retard and the timing light is reading 40 degrees! So something still needs tweaking in the timing. All the spark plugs are looking a little lean. What has me concerned ATM is the stock oil gauge is reading 0, the oil filter is hot though, I opened the oil cap and everything wet with oil but no oil is flinging about. So I turned off the engine and removed the valve cover and the cam is showing signs of minimum lubrication, the black marks on the cams cleans off with a piece of fine Scotch pad. @Patcon and the valve lash had tightened up so re set that. I took the oil spray bar off and it had oil in it. So, I'm thinking of lathering the cam and rockers with assembly lube again and start the engine to see if oil is coming out of the cam tower holes, then reattach the oil bar and see if the stream of oil is hitting the cam. The oil pump is new and is the upgraded one used in the later Z's Opinions?

The front and rear fender wheel lips can be rolled up to help get you a bit more room, what size are the tires?

Oooo, that's a useful tidbit, I'm going to write that down and pin it to the shop wall.

That prediction of automatic trans cars starting to go up in price looks like it may be coming true.

Oh Lord let it be that easy, 12:35 I just pulled from memory and I should know better. Looking at it again I think you guys are right, I'm one tooth over from where I should be, it will have to wait until the morning now, I'll have to drop the sway bar first.

I did that during reassembly, In .20mm Ex .25mm

OK, I've hit a wall and need someone else's eyes, I can't get the engine started and I'm afraid the gas is pouring down the slope of manifold and into the cylinders like it was when I opened the engine. Weber triples, specs on the first post, DCOE made in Spain with plastic floats, float levels set at 12mm from the top of float to carb lid, 1.5mm droop, butterflies set covering the first progression hole closest to the intake, Idle mixture screws 1.5 turns out. With the #1 piston at TDC, #1 cams pointing out, oil pump shaft set at 12:35 on the clock dial, distributor set at slightly advanced, firing order 153624, quadruple checked all leads going to the right sparkplug. I didn't check all the sparkplugs but #1 is sparking well. Just won't start, any ideas? Thanks

Agree, it's not a great seal, if you keep the hatch closed and let the car sit out in the sun it will start to relax over time. I used a Kia Sportage door seal on my the hatch for years and it worked well.