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The only place for a coil spring is up Zebedee's
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Joined: Apr 29 2020
Posts: 39

Hi all -

In the past I've mentioned planning the rebuild of a spare engine of mine off my parts vehicle and swapping that into my daily driver. Unfortunately I don't have as much time as initially thought so I've settled for only rebuilding from the cam "up". The main items to be replaced are the cam, lifters, and pushrods as well as the oil pump gears, timing chain, and the water pump. My parts vehicle cylinder heads are right now at the machinist.

The daily driver engine gives off a sharp smell (I wouldn't call it sweet), drips from the exhaust pipes, and has a noticeable leak near cylinder 2.

What all should a machinist specifically do to these heads? Like, what should I tell the machinist to not miss doing.

I had the rocker assemblies with me at the the time I was dropping off the heads. He looked them over and said the wear points on the rockers (the pushrod cup and the point where the rocker touches the valve) looked great and could be reused as is. My pushrods got mixed up and since they're cheap I threw them away. As mentioned the lifters are getting replaced, so if the lifters and the pushrods aren't mated to the rocker (by common wear points) is it true the rockers can be reused? He'll also test the springs but again said it's not a common LR failure point and they could be reused. Frankly he gave the impression that short of failure every bolt, washer, and spring could be reused and not to spend money unnecessarily. His opinion was that it was a very low drama engine, but I'm not taking advice from my housekeeper on how to rebuild my house so to speak. The guy is well regarded, knew the engine well, and seemed knowledgeable in person but I have no direct experience with him.

The rockers need to be shimmed?

The plan is to tear down the rocker assemblies, clean everything with an ultrasonic cleaner, and reassemble them. Is this wise and necessary or am I just making work for myself? If I do that how do you get the rockers back in exactly the same place? I figured on lightly scoring the shaft where each rocker should go. The engine has had an intermittent tick since I bought it so figured best to get all those oil passages as clean as possible. If the tick is caused by a slipped sleeve so be it, but usually it happens when I'm low on oil.

How much extra work would it be to do the rings and rehone the cylinder walls with a drill attachment? Youtube videos make it look straightforward.

I planned to stick with OEM cylinder head bolts. They're cheap and they've done the job thus far just fine.

Last question (for now!): Please advise which camshaft brand to go with: $57.09 from 'Original Equipment' sounds like Britpart.

Cheers!

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Joined: Aug 05 2019
Posts: 159

As for the heads. Check in four directions with a steel straight edge. Along, across (in several places) and the diagonals. This will show how much, if at all, the heads are warped. Skim only the bear minimum to take out and any warp and marks.

Check the guides for wear and replace if needed otherwise it will have a thirst for oil. I don’t know if you are planning to go as far as lapping the valves, but it would be a good idea whilst you are that far in, budget permitting.

You will see, looking at the block if a liner has slipped, it is pretty obvious. Run your fingernail out from each bore and see if you get a catch.

Stripping the rocker shafts is a good idea. Get rid of the crud and see if the shafts are scored or worn. That could be your tick right there. Don’t score the shaft, the springs will locate the rockers. As you are using new rods, the order of reassembly is less important.

OE cam is fine and as you can see, cheap. At least if it is Britpart, it comes with a 2 year warranty, unlike LR which comes with a one year warranty.

Dropping the pistons, honing the bore, new rings and bearings etc will definitely brighten it up. Cover the exposed journals whilst honing the bores. You will of course be up for rings, big ends, big end bolts (I think from memory) and mains as you aren’t going to go that far and not do them. If budget doesn’t stretch that far, leave the whole lot together.

If the budget does stretch a little, go for as set of head studs and nuts as opposed to new stretch bolts.

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Joined: Dec 30 2015
Posts: 5213

As said, skim the minimum off the heads to get them flat. Take the valves out, clean the carbon off the top of the heads and give the seats a gentle lapping with grinding paste. Check for wear in the guides. Unless a lot has to be skimmed of the heads, it's unlikely that you'll need to shim the rocker pedestals but it's easy enough to check (see http://www.v8developments.co.uk/technical/valve_train/index.shtml). I'd also go for head studs as you've no way of knowing if the replacement head bolts will stretch as the original spec called for.

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Joined: Aug 07 2019
Posts: 220

if he takes 10 thou of one head he will take it off the other or they will be unbalanced , if he removes the valves he will most likely reface them and do the seats on the heads as well, and fit new valve stem seals
as for the rocker gear if you dismantle you will see the hard metal on the shafts has most likely worn while the rockers are most likely good(its strange how the hard steels wear against the softer alloys) so i would replace the shafts before the rocker gear unless the rocker gear has wear then do it all.
how is the appearance of the inside of the motor , is it black and crusty or oily and clean

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Joined: Dec 29 2015
Posts: 760

So if I was buying parts to refresh the camshaft, I should probably throw a couple of rocker shafts into the order too? But the rockers are likely to be okay?

Mine are all the "bad" castings where the seats are supposed to sink, but I figure they'd have done that by now if they were going to.

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Joined: Aug 07 2019
Posts: 220

its more about cost , if you can afford to replace, buy as a kit , thats a quality branded kit not some Chinese or unnamed white box ?you have to dismantle to see if its worn . the wear will be on the bottom of the shaft and rockers , just move the rockers around and look for wear , slide them half of the seat area and see if it has wear around these areas , turn the rocker upside down and see if the clearance is different , this will show the wear in the rocker . if you want to clean the shafts use something like brasso ( non abrasive liquid polish). in some cases its very obvious and other not so, its now up to your discretion or the repairer
PS whats the inside of the motor like?

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Joined: Mar 22 2016
Posts: 1227

As you’ve got it out and heads off, I’d throw a fresh set of rings in as well, there cheap enough, it gives you piece of mind that the oil rings are good at the same time

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Joined: Apr 29 2020
Posts: 39

I have an engine pulled from my old 1999 vehicle. The heads have been removed and I'm getting them machined. Still to be done is clean the 1999 rocker shafts up. The rocker arm surfaces look really good and I plan to reuse them.

There's also a 2001 that I daily drive. The problem with the 2001 is the head gaskets are going, it's drinking coolant, and I have a low oil pressure tick. I can't give a number but it goes through oil very quickly. I've not cracked the 2001 engine yet so I don't know how it looks inside.

Since I've not done this before and I have an engine free to rebuild how much more work is it to rebuild the bottom end of the engine? The cost breakdown from LRDirect it's not that much more... so maybe I should just do it all and then swap the entire engine over. If it's harder than it looks then I'll just stick to timing chain, water pump, cam, tappets / lifters, pushrods, cylinder heads on the 2001.

Thank you for the questions and advice. I'll get back to you on them all here shortly.

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Joined: Apr 29 2020
Posts: 39

Let's assume I want to rebuild my parts engine and swap it over rather than just use the cylinder heads for my running vehicle.
My question at this point is really just how much harder is it to do the bottom end of the engine. How about time wise?
I've been reading through it all and it doesn't seem particularly difficult. (Total arm chair response that!)
Cost wise the parts to do it all aren't really that big a deal considering the outcome.

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Joined: Dec 30 2015
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If it's out, it isn't any more difficult than it looks reading the overhaul manual. If I were doing it I'd hone the bores to get rid of any glaze and treat it to a set of piston rings and big end bearings. I'd pull a main bearing cap and see if there is any wear on that (unlikely unless it's been really neglected in the past) and, assuming there isn't, put it back. Treat it to a set of core plugs (dead easy with the engine out) while you are at it. If you get it right, you could end up with an engine that will be oil tight for a few weeks at least.....

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Joined: Aug 07 2019
Posts: 220

you will want mains, big ends and a set of rings . thats the minimum . if their is no lip at the top of the bore then a light hone and another set of rings , if their is a lip then i recommend boring to clean up the bore. it will be outer round? this will require pistons and rings(over sized usually 20 thou)
crank grind if worn or ruffed up
cam bearings replaced have this done when being bored
welsh plugs
if you not comfortable fitting the crank or any other part just ask the engine repairer how or if they can do it for you.
hope that helps, or a least confuses the crap out of you. its not hard , nothing money and time wont fix like all repairs, keep it clean.

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Joined: Apr 29 2020
Posts: 39

I really appreciate you guys tolerating me thinking out loud through all of this. It's best if I just stick to doing the top end of my running vehicle and next year I can do more if I need to.

Got my cylinder heads back today. Skimmed 0.002" off the deck. He also replaced the guides, valve stem seals, and did a valve regrind then pressure checked them. I went to buy some some valve honing compound from him and he said I don't need it as that's the purpose of the grind and pressure check. The springs all were to spec so none were replaced.

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Joined: Apr 29 2020
Posts: 39

Just started running my rockers through an ultrasonic cleaner. Is wear such as this from the rocker shaft considered acceptable?
Also the grooves in the last image are not deep but you can catch a few with your fingernail just a little bit. The zoom makes it a bit more dramatic than it is.

All the rockers I've done so far have them. Considering the engine ran well before I pulled it there probably isn't much of an issue here.

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Joined: Aug 05 2019
Posts: 159

Lurveelee!

I’ll get howled down for this, but I think I’d re-use them for a budget rebuild. The shaft condition would be more important, what do they look like?

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Joined: Apr 29 2020
Posts: 39

Haven't gotten the pillars off yet as they seam to be a friction fit. Once I get those off i'll pull the other rockers and inspect the shafts. I wanted to try out the ultrasonic cleaner so I just did the easy to access ones for now.

If it's better to just build new rocker assemblies I can do that no problem...

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Joined: Aug 19 2019
Posts: 241

I think he's probably right about not needing the valve lapping compound, but quite a number of years ago I worked in a shop that overhauled aircraft piston engines. We did 3 angle grinds, and then still lapped the valves in.

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Joined: Aug 07 2019
Posts: 220

i would use them to . the good thing about the rocker assembly is its 4 bolts and on the bench plus the cover of coarse, so if not happy easy to replace
when they do sets on heads they cut them with a tool now, no stones, so they are very accurate , no lapping in required
not shore about these heads but when i had the heads done on my old 3.5 L when they cut the seats they shone like mirrors because of the hi nickle content in the seats , i imagine these are the same. looks good .