spray bar gasket?

[steve91tt]

I'm in the process of assembling an engine and I need to know whether or not to put some sort of gasket material on the spray bar to cam tower joint. I want to make sure that I minimize the oil leaking out of the joint. However, RTV makes me nervous as it may break off and plug the spray bar holes. I wasn't able to find any mention of a gasket in the FSM. Anyone have any experience with this?

[240260280z]

I agree, blow out the oiler bar or spray-out with carb cleaner using a stray (I hit each hole to back flow then tip on end and spray from the inputs so that all 6 holes flow the same.

Just use the cheap felpro gasket paper from any autoparts shop and cut new gaskets to fit the margins of the tube with appropriate holes for oil flow..

[Zed Head]

I happen to have a 1976 spray bar in a box in the garage and just took a look at it. It does have a gasket at the interface. Not a precision piece, essentially a square of gasket material with two holes, one for the oil and one for the bolt. Pretty sure the head has never been touched.

p.s. don't forget the hole for the oil.

[30 Ounce]

There is no gasket between the towers and spray bar. I have had a couple of spray bars come apart on me and would recommend this:

[Zed Head]

I took a look here - http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Engine280Z/CamshaftValveMechanism/tabid/1603/Default.aspx - and here - http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Engine240Z260Z/CamshaftValveMechanism/tabid/1565/Default.aspx -

and see that the 240/260 spray bar is different from the 280Z. Doesn't show a stock gasket on either, so I'm not sure why mine has one (two actually).

30 ounce has a point though, you might do some preventative brazing on your stock tube while you have it out, if you don't want to spring for a custom billet bar.

[steve91tt]

After taking a closer look at the spray bar I don't think a gasket made from parts store gasket paper would work very well. The spray bar is only held on with one bolt per cam tower. If I put a semi rigid gasket material in the joint I'm afraid that it would compress at the bolt and not at the oil hole. It may even cause the oil bar to deform. If the oil hole had a bolt on either side then the gasket would likely work fine.

I'm considering removing the spray bar and blocking off the holes. The cam that I'm using is internally oiled. I bought it from Rebello. Dave recommended that I run both spray bar and internal oil system at the same time. However, after reading about several spray bar failures, I may be better off to use the internal oil system only. I'd rather have all of the oil going through the cam rather than risk having some or all of it leak out of a broken spray bar.

[madkaw]

Your probably better off with just the internally oiled. Somewhere in the archives here I have a thread where I experimented using both I couldn't get it to work. The internally oiled cam seemed to rob too much oil from the spray bar and the oil spray didn't even reach the lash pads. I'd like to know how rebello got both to work and proved they both worked

[madkaw]

Search- cam oil investigation

[240260280z]

Your probably better off with just the internally oiled. Somewhere in the archives here I have a thread where I experimented using both I couldn't get it to work. The internally oiled cam seemed to rob too much oil from the spray bar and the oil spray didn't even reach the lash pads. I'd like to know how rebello got both to work and proved they both worked

to

The "how to rebuild..." book references enlarging the oil passage to the head. Maybe that is what Reb. does to increase flow to both oilers.

[steve91tt]

Search- cam oil investigation

I'm not finding useful information using that search strategy. Do you have a link to a thread?

[Zed Head]

Blue might actually be referring to the book "How to Modify Your Nissan & Datsun OHC Engine" by Frank Honsowetz. On page 15 he describes enlarging the oil-jet from 2.0 mm to 3.17 mm to increase oil flow to the head, but it's in reference to big cams and high spring pressures.

Some people, over on Hybridz, have suggested that there is plenty of flow to support both spray-bar and internal oiling. Others suggest drilling out the oil-jet to be sure. Your oil pump condition is probably a factor also, considering the lower flow at low RPM.

Seems like Rebello would know about drilling out the oil-jet. Probably worth a discussion since he suggested it.

p.s. the flat head of a good bolt should (did, in my case) provide enough pressure to seal the spray bar, with gasket, to the tower. The pressure in the bar is reduced due to the oil-jet restriction. The gasket on my 1976 spray bar was well-compressed and showed no signs of distortion or leakage. It was smashed flat like a typical old gasket, very evenly. No signs of uneven load.

[madkaw]

I did enlarge the oil passage. I handed the how to modify book to my engine builder and he followed all the suggestions- including that one.

Steve, working off of a I phone so not any good at copying links. I found it by searching 'spray bar'