L18 re-build, pics and questions - long post

[zed]

So, I finally pulled and stripped my first L motor ... was a really interesting job and not difficult...

Battled to get the rear main bearing cap out - is there any trick to this, apart from hitting it with a block of wood? Also, how do I get the pilot bushing out? Honsowetz book says to replace it with a roller bearing?

Pistons, bores and head look ok - which is strange - the motor has done 400 000km/250 000 miles. There was also a bad rattle on start-up - maybe piston slap? But, I can't find any signs of the cause of this - where to look?

Number 3 rod bearing had a bad score on it

 

I've taken the head and block for a .020 skim and bore to 86mm - (gonna fit L28 flat tops!)

Questions: what stone grit number to use to hone the bores? Honsowetz says 400? Why was there piston slap - pistons are not scored or loose in the bores, there is hardly any ridge? Is there a trick to replace the rear main bearing cap? Can I lap new valves onto the old seats - the seats are fine, I don't want the machine shop to touch them, in case they mess up...they work mostly on tractors...

thanks for any advice

[pl521sss]

L18L28 Flats tops are hard to find

And if you do, it's expensive

There's a set in ebay and guy wanted $350

 

Have you considered doing L18 long rod?

Piston for that is also hard to find

[banzai510(hainz)]

pilot bushing?????a chinese hammer. Its a sliding handle/rod with claws at the end or screw(or what ever the method to pull the Part out)

I have the machine shop do it while its there.

 

PS save the old piot bushing to make sure the new one is the same. I ordered spares myself recently and 2 different ones showed up!!!!!!!!! same part on box.

No need to get the needle bearing race ones as per that book.

 

 

get nissan Main side seals they go in anywhich way as others have a funky spring set up. 12289-W0400

 

 

 

as for piston slap????? Could it be starter related or very loose timming chain htiing something. I like pull the front cover off so I can see how much the tensioer and chain slop there is while tearing down the motor. Bu you took the head off already.

 

 

Try to find a headgasket that is a little bigger in the bore dept. I got some 87mm from BAZ @ Datsport in Austrailia. mayb ethey have 4 cly l series gasket there that are bigger than 85mm

[zed]

I already got L28 flat tops here - cost R800, that's about US$90. Cheaper than L18 .040 oversize pistons...

[banzai510(hainz)]

PS That bearing is not that bad I would just RUN IT with new bearings

[LenRobertson]

Removing the rear main cap - at least on my L20B, there is a threaded hole in the bottom of the cap. I screwed in a bolt with flat washer, leaving enough room under the washer for the flat end of a small crow bar. Depending on the bar you use, you may need a thin block placed on the pan gasket surface to lever against.

If the engine has that many miles on it, I would be sure to check all the crankshaft journals with a micrometer. Rod journals can look smooth and yet be out of round.

If your machine shop has a hot tank to clean the block, that might be a good idea, due to the high miles. It cleans the gunk out of the coolant passages. At least I'm guessing you have hot summers there in SA.

 

Len

[zed]

thanks for the replies - appreciated.

Hainz - that rattle would stop when the motor warmed up??? I still can't find any wear in the motor to cause such a loud rattle...

 

So, I took the block and L28 pistons to the machine shop. Asked for 0.0015 clearance - from the Honsowetz book. This seems real tight - is it right?? They work on tractors out here....I doubt they can cut so close.

 

And, I tried to match the inlet manifold to the gasket and head ports. Those sharp edges always bother me. Used an old grinder and stones. Was real careful to stay inside the lines of the gasket. Suppose it won't make much difference, but it can't hurt any ...

[mklotz70]

The easiest way to get the bushing out of the end of the crankshaft.... Get a dowel(wood, steel, alum...whatever) that fits closely in the bore of the hole. Pack the hole about half full of wheel bearing grease(or any thick grease). Put the dowel in the hole and tap it with a hammer. The hydraulics of the grease not compressing will force the bushing out. Works really slick!