L28 Rebuild Advice

[Howdy]

That is some fantastic advice. That is the sort of thing I am looking for. I think I will try my hand at some light porting, but like you said, mostly just cleaning it up and matching it to the manifolds.

 

I am starting to think it may not be worth the hassle of upping the compression. It sounds like just bolting on the N42 head. Possibly just do the light head porting, and a cam, with my current head and see how it goes. 

 

Where should I send my cam to be re-ground, and if I keep the current head what grind (72 degree still)? Obviously to still match up with webers and an exhaust to match.

Agree with Dat2kman, Clive is good and has the Wade grinds plus some old racing grinds which cover most situations. Usually you can have the choice of grinding your cam which will probably require thicker lash pads or welding up your cam then grinding. I can't tell you how good welded cams are because I have never used one but the ground cams I have used have been good. Need to make sure you run any cam in properly. If it was me I'd use the 72 with your combo. I have used a 663 grind on a stock standard 240K motor with twin SUs and extractors only and it worked great. Also built a few other higher spec motors with big porting, high comp and 45 DCOEs and it also worked great for the street. I thought it was a good all rounder. Please someone correct me if I'm wrong but from memory I think the 663 is a 72 deg cam so was 288 duration and 0.335" lift at the lobe. I thought it was a grind used in some Datrally motors but might be wrong. I may even still have it somewhere because that motor died at Winton after being thrashed to within an inch of it's life then just one more inch.  The 240K was a one make series but there was only one 240K and lots of Drivers. It spat the lash pads a couple of times so I'd definitely run some new heavier valve springs.

[HomeBuiltByJeff]

Agree with Dat2kman, Clive is good and has the Wade grinds plus some old racing grinds which cover most situations. Usually you can have the choice of grinding your cam which will probably require thicker lash pads or welding up your cam then grinding. I can't tell you how good welded cams are because I have never used one but the ground cams I have used have been good. Need to make sure you run any cam in properly. If it was me I'd use the 72 with your combo. I have used a 663 grind on a stock standard 240K motor with twin SUs and extractors only and it worked great. Also built a few other higher spec motors with big porting, high comp and 45 DCOEs and it also worked great for the street. I thought it was a good all rounder. Please someone correct me if I'm wrong but from memory I think the 663 is a 72 deg cam so was 288 duration and 0.335" lift at the lobe. I thought it was a grind used in some Datrally motors but might be wrong. I may even still have it somewhere because that motor died at Winton after being thrashed to within an inch of it's life then just one more inch.  The 240K was a one make series but there was only one 240K and lots of Drivers. It spat the lash pads a couple of times so I'd definitely run some new heavier valve springs.

I will follow that cam up.

 

I checked, as best I could, the wear on my valves, valve guides, cam housings and crank and everything looks to be well within spec. 

 

What is the best place to get standard rebuild parts, e.g. gaskets, bearings, water pump, etc? Nissan? Rare Spares? 

[C.A.R.]

Stewart Wilkins: https://www.swmotorsport.com.au/

Edited October 25, 2017 by Lurch ™

[gav240z]

By the way p90a lifters look like this.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F401412087106

[HomeBuiltByJeff]

Ok. An update on this front.

 

I travelled out to see Stewart Wilkins today and I dropped off my head and block. After some inspection of the head, Stewart pointed out some corrosion around some of the water galleries. This will need to be welded up to repair it. While he is there he is going to also weld up the grooves on the edges of the inlet ports which were originally to accomodate the injectors for this fuel injected head. He is also going to shave around 1mm off the head to raise compression. He does hate doing it though, as he says, once you take it off you can't ever put it back on.

 

The block is just going to be cleaned and honed. 

 

I am going to give the head a mild tidy up of the ports when I get it back.

 

I have ordered a Kameari manifold and triple 45mm OER carbs, and I have already got my cam back from Clive cams with a 72 degree grind, so it is full steam ahead.

 

Stewart said the head and block should be done around the end of January, so hopefully there will be some detailed engine build videos in the near future.

[gav240z]

OERs seem to be a good option if you don't want to pay the Solex/Mikuni tax.

 

Usually later heads don't need welding up due to corrosion, but perhaps the previous owner of your head ran it without enough coolant for a long period of time? My E31 needed welding up, but it's about 10 years older compared to your P90. Not cheap to do, but only way to do it properly and the P90s are a good flowing head.

 

Car should go good!

[HomeBuiltByJeff]

I have no idea about the history of this head, but as soon as he pointed it out you could see the edges of some of the holes were quite corroded, some of them starting to encroach on the inner seal of the head gasket around the cylinders. 

 

He also gave me some nice tips on how best to give it a light porting job, so I think it should come out quite nicely.

[gav240z]

He also gave me some nice tips on how best to give it a light porting job, so I think it should come out quite nicely.

Eagerly waiting for that video, have some idea of what this might entail but keen to see it in practice.

[Scotty_Rah]

Ok. An update on this front.

 

I travelled out to see Stewart Wilkins today and I dropped off my head and block. After some inspection of the head, Stewart pointed out some corrosion around some of the water galleries. This will need to be welded up to repair it. While he is there he is going to also weld up the grooves on the edges of the inlet ports which were originally to accomodate the injectors for this fuel injected head. He is also going to shave around 1mm off the head to raise compression. He does hate doing it though, as he says, once you take it off you can't ever put it back on.

 

The block is just going to be cleaned and honed.

Are you able to pm me with a estimated cost of this sort of work Jeff? I too am looking to do the same thing soon.

[blu260z]

Are you able to pm me with a estimated cost of this sort of work Jeff? I too am looking to do the same thing soon.

Scotty I had my head done recently and lucky no welding had to be done. The head got hardness tested, leakdown test, wash, new valves and seats, Welch plugs, a deck on 3 faces all holes re-tapped a few helicoils put in and an upper engine gasket kit all up $1400

 

I took my builder 2 cylinder heads and 1 needed to be welded in the same spots as Jeff's. My builder said the heat put in can distort the metal and cause more issues so went with the other.

Edited April 2, 2018 by blu260z

[HomeBuiltByJeff]

My head had apparently warped previously and someone had shaved it flat again so that the face of the head was flat, but the cam side was warped. The welder straightened it back out again with the welding and then I had 3 faces machined.

[HomeBuiltByJeff]

Ok, time for another update on this front. As I mentioned previously, I got my head machined, and had the corrosion around some of the water galleries welded up. I also had the injector grooves in the inlet ports welded up. As some may have seen I had the head shaved originally .8mm and when I CC's the head and the compression was not where I wanted it. I took it back up to Rams and had them take off another 1mm making it a total of 1.8mm (2mm is common). I CC'd the head again and the compression ration was much better (I can't remember the exact figure, off the top of my head, but it is in one of my videos). I have port matched the inlet and outlet ports, but I didn't really touch them internally, as I didn't want to mess things up too much.

I found a couple of dodgy valves (one was bent and a couple were badly pitted). Stewart gave me a couple of used ones to replace those and I have lapped them all. 

It is getting closer to assembly time, just going through now and checking that everything is still within spec.

Well I am quite happy, I just went through and measured the clearances of my pistons and the bores including the taper and it is all well within spec which is a relief.

I actually thought the bores would have more taper than they do, but the largest taper is 0.05mm. As for the piston to bore clearance they area all around 0.11mm where standard is 0.05 and max is 0.22. The crank is also well within spec, so I can still use standard bearings. Hopefully this should all go together nicely.

I have got myself new rod bolts, and I have to have a look at getting some new head studs (I was considering reusing them, but it sounds like it is not worth the risk). The rest I am planning on reusing.