Can any one tell me wether the rocker arms in l series are the same, i am rebuilding an l20b and need to get a couple of rockerarms as 2 of mine are stuffed.

thanks
luke

i swaped all running gear from a L18 a87 head on to a L20b head (not valves though). no probs with rocker arms

You should get them radius ground so you have a good clean new wipe from your cam. All of them should be of the same weight too.

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1928 Model A CC Pickup

Just built a rally engine, used second hand rockers, that were the best I had seen for a while. Downside - Cam lasted 4 stages b4 we retired with a loud knocking noise - and one damaged lobe.

One new CAM later and 8 new reground rockers and hopefully all will be fine.

So I agree with Yellowdat - one set of reground rockers for a new CAM, see Stewart Wilkins - he does an exchange.

Damn i wish i knew that earlier, the motor is going together this weekend. I bought 8 rocker arms second hand so have 16 in total, so hopefully can get a good 8 from that lot. I may send 8 to stuart wilkins just incase.

Thanks for your help everyone

Luke

Hey Luke. Do all of them mate. Just take them down to your local machine shop or engine building shop and they can do it for you. It will only cost you around $40 for the lot. If you want your valve train to stay in good nic and last for a long time this is the only way to go. Are you replacing the cam with a regrind? If so you will need larger lash pads as well to correct rocker ratio. Do not use shims. Your machine shop should be able to help you with these to. Brad

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1928 Model A CC Pickup

Looks like my problem was more than Rocker arms, exhaust valve has been hitting pistons, fortunately nothing broke and for some reason valves are not bent.

I wonder how much I have to replace, I guess I now have:

Cam
Rockers
Valves ?
Big ends ? guess they would have had a hard time

I bought a brand new Ivan Tighe cam, i bought new lash pads but they were to big. I managed to get another 8 rocker arms and we made the best of a bad bunch, all the ones on the cam side are fine but the lash pad side wasnt a priority. I have a mate who works at Nissan and he is going give me a price on 8 brand spanking new ones.

Do you know what size pads you need yet? You will need a micro meter to measure the thickness of the lash pad. Measure the pad from where it sit on up of the valve to where the rocker arm sits on the top. write this down. Now get some per blue and coat the rocker arm in it. With the lash pad in place and rocker at the right clearance to the cam rotate the cam clockwise and see where the wipe pattern is on the lash pad. You want it to be in the centre of the pad in the rocker. If it's not then get a set of feeler gauges and put one under the rocket tip where it sits on the lash pad. You have now raised the rocket a bit. Readjust the rocker to cam clearance and coat the rocker pad in per blue again. Rotate cam and see where the wipe pattern is. Ounce you get it right write down the feeler gauge size for the valve. Move to the next and do the same. It should be close if not exact on the next valve. Ounce you have written them all down you will be able to go to a performance shop and buy the right sized lash pads for you cam. I don't think Nissan will have them. Try datsport www.datsport.com Nissco www.users.bigpond.com/dat1600workshop or Stewart Wilkins http://www.swmotorsport.com/home.htm All these shops should have stock. Have fun dood. Brad

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1928 Model A CC Pickup

rocker adjstment.
I use a fat blk tip pen for the wear pattern.

Rememebr the lash pads that come with the cam kits are a best guess size wise. Pretty close with a new cam like .160. But a regrind will usaually take a bigger lash pad and hopefully you have a bigger retainer also and not a stock size retainer.

if head was milled valves grind,seats grind and valve stem seatted(all sticking out up top the same amount will detrimine lash pad size. If good machine ist it will be close enough to use all one size

Note on 3rd photo I could use a bigger lash pad but wear pattern is close to the pivit end(ball) with in .015(wear pad) which is still OK. This will cheat the system a little bit by giving a little higher lift. So 10-20(bigger) thou of the lash pad size is not going to be a big deal on this one and save some money on buying a assortment of lash pads

A good engine builder will have all the sizes avail .150 up to like .330 or buy one of each then write # down and note location then order correct size.

Remeber the taller the lash pad the wear patern will be closer to the valve stem. Shorter lash will be closer to the pivit ball of rocker.

When we put the motor together we tried the larger lash pads which were way too big and put the standard thin pads back in, so going off that i need to get the ones which are inbetween these to sizes( not sure of actual thickness). The ones i bought with the cam i will simply take back and get some smaller ones, then all i need to do is get some reground rockers and away we go again.

get the pads reground before you check the thickness of the pads you need. The removed metal from the pads will alter lash pad thickness required.

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A little knowledge is a dangerous thing.
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"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT