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I started a post (https://www.yotatech.com/forums/f114...akdown-286395/) and got some great advice but now I know more of what's going on and have some specific questions so I'm starting a new one about the engine specifically. This is kind of long and probably boring but I've got some questions at the end I would love some advice on. Until a week ago I've never done more than replace some brake pads so bear with me if I ask some dumb questions...
I have a '75 Pickup with a 20R that I just got. It sounded like it was running great except it was going through a ton of oil (like 1qt+ in 100 miles) so I took the engine out and tore it down. There was no oil on the ground and not a lot of oil smoke except a puff at startup but it did smell a bit in the exhaust and I think it was basically going out every way it could: valve seals, main seals, and through the rings...
Here are a couple shots of the truck and of the engine coming out:
You can see gunk all over the valves. The plugs were pretty black too. I took the head to a shop to get hot tanked and checked over and I started taking the engine apart. Here's the rear main seal:
Bad news there- it had a spring in the seal that had partially popped out and wore a groove like 1/16” into the crankshaft!
Then I tried to measure what I could with a feeler gauge. The crankshaft rod clearance supposed to be max of 12thou. It was like 10 or 11 on pistons 2, 3 and 4 and on number 1 it was like 11 or 12 or maybe even 13. It was kind of hard to tell, I could get the gauge in a little bit but it didn't feel like it was going all the way down to the shaft. I'm not a precision guy...
Next I pulled the pistons. They had some vertical scuffing on them (also on the cylinders). The bearings had some straight scuff marks but didn't look too bad (to my untrained eye) except on piston no. 1 where there were chunks flaked off.
Pistons:
Chunks coming off bearing no. 1:
The crankshaft shaft looks pretty good, to my untrained eye:
I don't know if this bit of scuffing on the pistons is bad news or normal. Obviously the flaked bearing is not good...
Next I pulled the top ring off of piston 1 and put it in the top of the cylinder then pushed it down about halfway with the piston and measured the ring gap. Holy smokes:
That ˟˟˟˟ is like 1/32”! There's also visible wear on the ring, kind of like the top was shaved off wwith a little ridge left. At this point I took everything to a good motor shop to get some advice. They were pretty busy but very helpful considering. They mic'ed two of the cylinders and both looked awesome, I think they were 3.484 and 3.482 or something and spec is 3.484. Pretty incredibly for a 40 year old engine. Almost seems too good to be true, considering that the ring gap is terrible and also that the pistons wiggle a lot front and back (not side to side) in the cylinder. Also he only took one measurement (at the top)... But these guys have been doing engines for decades and are known around town for being really good so I'm sure they know a hell of a lot more than me. I think he just figured if that one measurement was so nearly perfect and it looked good to his eye he didn't need to take any more. Is that reasonable? He did say that the front to back wiggle is normal because the pistons aren't actually round. He didn't bother mic'ing the other two cylinders at that point he just glanced at em. Then he checked the ring gap and it was like 25 or 30 thou – really, really worn. He only checked the one ring since it was obvious at that point that I needed rings. He also told me that he could put a sleeve or a bushing or something on the crankshaft where the groove was. I forget exactly what he said, just that he could fix it without needing to replace. He didn't check anything else or ask more questions, just said I needed rings and the crank fixed and also that I needed to get a new timing tensioner. The timing chain managed to half eat the heads off a couple of bolts in the timing case!
So here's where I'm at:
-Once I get the head back I'm going to replace the valve springs and seals
-Replace the rings and rod bearings and get the crankshaft fixed
-New timing chain tensioner\
-New front and rear main seals and gaskets of course
Hopefully this will get me running smooth again. I have some questions though:
Should I check or replace the main crankshaft bearings while I'm at it? I guess to get the groove fixed I'm going to have to pull the crankshaft anyway? It spins by hand butter smooth right now.
Do I need to worry about replacing piston no. 1 (or all the pistons)? If the rod clearance is right at the max or even a thou over is that a big deal on a work truck? What I can find online makes it seem like bearing oil clearance is the big one and side to side clearance on the rod is a lot more forgiving unless maybe you're racing. The clearance between piston and ring seemed mostly within spec except on that super worn ring.
Do I need to mic the pistons? I forgot to ask the shop to, but isn't the point of that mainly to be sure that new pistons aren't too big for the block? I don't have a micrometer.
Is it foolish to just replace the timing chain guides and tensioner ($15) and not get a whole kit with chain and sprockets ($50?). I hear these double chains often last longer than the engines. The chain looks good visually and the sprockets have a lot of tooth on them, they don't seem very pointy but maybe a tiny bit sharp.
How much can I trust rockauto to have the right parts as far as bearings and stuff? Like if I order these 'standard' rod bearings: http://www.rockauto.com/catalog/more...382&cc=1277074 can I just throw them in or do I really need to measure everything and first? If so, how do I measure it? Remember this is a work truck, not a race engine...
What about the quality of stuff on there? I can get main seals for $1.50 http://www.rockauto.com/catalog/more...248&cc=1277074 or $10: http://www.rockauto.com/catalog/more...146&cc=1277074 . I'm inclined to get the $10 ones because I would really feel like an idiot if I had to pull the transmission to replace the rear seal cause I wanted to save $8.50. But generally there's this huge range of price for parts and I usually just order something in the middle. Is there a better way to do that, like a list somewhere of quality parts manufacturers?
Is this “Conversion (Lower) Gasket Kit” what I need?: http://www.rockauto.com/catalog/more...960&cc=1277074 'Lower' sounds right but 'conversion' sounds wrong... When I thought I was just doing the head I got a head gasket and intake and exhaust gaskets and I think all I need it the seal cover, oil pan, and timing chain gaskets but I'm probably forgetting one or two... Seems like a waste to spend $50 if I'm only going to use half of an engine gasket set...
Should I replace the freeze plugs while I have the engine out? I hear sometimes they rust through on old truck but I don't want to open a can of worms if it's hard to put new ones in and get a good seal...
1-you have it appart, might as well do it all.
2-replace all the pistons
3-a good machine shop will fit the bore to the pistons for a perfect fit.
4-replace the whole timing set - I brand new double row set laying around here somewhere if you are interested.
5-DO NOT BUY REBUILD PARTS FROM ROCK AUTO. Go to LCE or Engnbldr to get a rebuild kit. If you go with Engnbldr (that's who I use) you can get every thing you need in one place for the best price.
6-Again, no no
7-The engnbldr rebuild kit comes with all the gaskets you need for a complete rebuild.
8-yep
9-Do you ever see the idiots on youtube driving to cars with the engine they just hone? No? Do you wonder why? LOL Honing is not something you should do without a) the right skils, b) the proper stones and c) the proper measuring tools. Do you have all three of those? No? Then take it to a machinist.
10-by hand
Here's the deal dude... It sounds like you are trying to go with a budget rebuild. While rebuilding an engine can be done rather economically, you CANNOT cut corners and expect to save money in the long run. I have a rebuild thread on my last rebuild that goes through the steps you need to take. Follow that and you'll do just fine. Get a FSM too - don't rely on Chiltons or Haynes manuals.
Problem with engnbldr is that he doesn't seem to carry much (anything?) for pre-81 trucks. 20Rs in general. But send him an email or give him a call. He's typically very helpful. But very busy.
I agree...I don't know much, but once you're talking about an engine in need of a rebuild, you're talking about an engine in need of a rebuild. Not an engine in need of "well, let's replace this, but leave this...replace this, but leave this..." etc. You'll wonder why, a few thousand miles down the road when something isn't right, you didn't just do it all when it was apart.
I know what you mean with it just being a work truck. And if it was an old functioning beater, you could just tool around in it till died sometime years down the road.
But it's looks like it ain't that...
You can buy parts from rockauto, but I agree with Dave. If you're going rebuild kit, get it from a Toyota specific source.
If you know how to look at rockauto, you can find the parts that are OEM quality or better, and what aren't, and just don't buy the ones that aren't. I got my oil and water pumps from rockauto and they had Aisin stamped on them. Stock Toyota parts.
But they also sell felpro and other cheap crap parts.
Ok Ok, point taken. Thanks for pointing me to that rebuild thread, that's really helpful. Same with lce/engnbuilder, I was definitely feeling wary about rockauto but it's just so damn easy to find parts there... Like 83 said it doesn't look like engnbuilder has much for the 20R which sucks cause lce is really expensive, like twice the price of engnbuilder for a lot of stuff...
Looking at your rebuild it seems like you want to do everything perfect the first time and never have to worry about it. Wish I could do that but I straight up don't have the money to do a total rebuild right now. I'm not trying to cut corners but this is my only vehicle and I have to get this truck back on the road with the resources I've got. At least it's easy to work on this engine if I have to redo some of this stuff in a couple years...
So I'm not going to bore the cylinders if they're within wear limits but I am a little wary of how quick that guy checked em. I think I'll ask around about another shop and get a second check.
If I'm not boring the block, do I really need new pistons? If they're within spec why replace them? Or are you saying that because of the questionable rod clearance numbers I got? But then it looks like the lce kits don't even come with piston rods...
So what if I do this?
Main seals, bearings, and rings from LCE
Decent Fel-Pro gasket kit and Sealed Power valve springs from rockauto ($100+ double racing springs is all LCE carries for the 20R)
New double timing kit, probably from rockauto to be honest because it's $150 from lce versus $70 for the 'expensive' one (Cloyes) on rockauto which has a lifetime warranty. Ok that doesn't mean much if it breaks and everything goes to ˟˟˟˟ but I'm guessing if they're willing to put a lifetime warranty on it it's probably reasonably well built.
I'll take the crankshaft out get a shop to properly measure the block to make sure it is within wear limits and do the same to the crankshaft which I'll have them repair. Will they tell me what size bearings I need when they check the crankshaft?
I'll have the shop do the honing and I'll put the rings in myself.
I would like to re-use the pistons if at all possible.
Oh, and how do I figure out if I need shallow or deep oil groove rings? Can I measure the depth with a dial caliper or do I need to get that done by the machine shop with something more accurate?
No more than pistons cost, I would replace them even if your's are in good condition. Think about it... Pistons are constantly beat up and down and heated up. Metal (especially aluminum can only take so much abuse. They may look Ok, but there is no true telling when they are about to detonate. You can reuse your old rods - that is perfectly normal to do unless they are bent which is unlikely if you didn't experience total engine failure.
Here are the steps to the rebuild:
1- have the machine shop check the bore to figure out if you a) have severe scratches in the cylinder walls and b) have excessive wear. It is really quick and easy for them to do with a bore micrometer. They will tell you if it needs to be just hone or bored (and how much to bore)
2- you can usually visually inspect the crank for wear, but you'll have to break out the plastigage for clearance. Check the clearances on the mains and rod bearings. Get an FSM to get the tolerances for each. Unless you have extreme wear, most of the time you can go with STD bearings on the rods and mains.
3-order your parts according to your findings BEFORE any machinist touches that block.
4-take the block, pistons, rods and bearings to the machine shop and they will machine everything to fit perfectly. Make sure that you take all your rod caps and main caps to the machine shop and provide them with the proper torque specs per the FSM. If they deck your block without the main caps you can get a "twisted" deck from where the torque wasn't present when the machining was done. It's the little things that make a difference. You'll need the timing cover and rear seal retainer too since they will need to be decked with the block.
5- Have the machine shop fit your wrist pins and bushings.
6- Pick everything up and start assembling.
7- if you decide to do the head, you'll be in for a big bill from the machine shop. Cutting valves is typically not cheap. A full head job bill from a machinist will run you at least $350 and that is considered cheap. See what is worth savig and/or needs to be replaced. Sometimes a new valve seals and valve lapping is all you really need.
8- DO NOT USE FelPro gaskets! Get a quality gasket kit from LCE or Engnbldr.
I called engnbuilder, turns out he does have the rebuild kit for the 20R at about the same price as the 'economy' kit from lce that comes with some bull˟˟˟˟ single timing chain. That guy is awesome. When I do the math I guess I'm looking at 250 or so for my half-ass approach versus 350 for the full kit, so I guess you're absolutely right about doing it all. Any idea what a block honing or boring is likely to cost me? The guy at engnbuilder said he charges almost the same to mic and hone vs. bore and hone because it takes almost the same amount of time, but I dunno if that's standard practice. Between what I'm hearing here and from him I am thinking about boring oversize to be sure I get it right, I just don't want to run out of money before I put the damn thing back together!
edit - that was a dumb question. I just called the shop to ask and it's only $25/hole to bore and hone. Way cheaper than I thought. Awesome.
As for the head, I'm not getting it done, they're just hot tanking it and looking over it for me. Said it would be like $40 which seemed worth it versus hours of hand cleaning! Then I'm going to lap the valves and put in new seals. Hopefully that's all it needs. I do have a spare head from a corolla sitting around so if I need parts hopefully I can pull em off that.
One more question. What is the procedure for measuring the bearing clearances? The FSM (which I've got) shows how to do it with bearings in in order to check if you need new bearings, but if I'm measuring to decide what size bearings do I take the bearings OUT in order to know the amount of space I'm trying to fill? It seems like if I leave the bearings in and plastigage it would be telling me the gap but not telling me how much of that gap is crank wear versus how much is bearing wear? Can I measure the plastigage with a dial caliper or do I need a micrometer?
I have to agree with Kawa for the most part here...
When I rebuilt my 20R I bought a kit from Northern Auto Parts. It was pretty cheap. ITM makes good usable components in my experience.
The hate for Fel-pro I don't understand. Fel-pro is one of if not the best gasket maker in the world. I use Fel-pro on everything. So do guys building turbo/supercharged engines going into sub-10 second 1/4 mile cars. I have rebuilt FE's, SBC's, 20/22R's, etc... Never had a problem with Fel-pro. However, there are alternatives that work well too. Am I missing something? Did they recently begin outsourcing and their quality has dropped? Haven't built an engine in about 4 years...
At a minimum disassembling an engine will require what is known as a 're-ring' kit. I have honed cylinders and 're-ringed' engines before. Even for someone who has a lot of experience a general rebuild is still usually best. I wish there were an easier answer for you, but I have to agree with Kawa in that you really ought to have a machine shop handle boring it out. There are corners you can cut, but realistically there aren't any you should cut and that you won't regret later if you do. I wonder if you even had appropriately sized pistons. That ring gap was massive. That was not a flaw, that was the wrong size ring.
At a minimum I recommend a crank polish with fine emery cloth. You can do that yourself. Just polish each journal evenly until the shine is somewhat dulled to break the glaze. This is assuming your crank mic's out and has no deep gouges in any of the journals.
I've done this myself. Wasn't smart enough to use the shoelace though...
Replace all crank and rod bearings. Absolutely. I have rebuilt engines without machining/turning or truing the crank and rods. You should measure them so the poor thing isn't slapping itself to death.
Plastigauge with your old bearings. Mic the bearings and see how much they've worn from the stock spec. Use that to tell the difference. If it's usable, slap the new ones in and go. No crank turning necessary. Measure first, polish the crank later.
Edit - About your head. Make sure it's flat. Real flat. These aluminum heads warp when you look at them cock-eyed. If it needs to be cut ask the machinist if he recommends a shim. You should be able to do all of your own assembly if you have the torque specs. Pistons go in a certain way. Ask the machinist to label each piston with it's proper hole and an arrow to indicate which direction it needs to face. There are oil galleys inside rods that need to face a certain way to oil properly. Your pistons are probably going to be notched, but just ask the machinist to sharpie it for you. Torque rods and mains in steps, from the center out. Just like a head. You don't want to fully torque one side of a rod or main cap with the other side fully loose.
Ugh, more stuff comes to me all the time. Boring is usually 15-30 bucks a hole aound here. Honing is exactly the same. When getting new pistons boring is the way to do it. I try to take the bare minimum necessary but if you want a 2.3L bore it out .060. My 20R was on its third rebuild before it went to .060 over.
Edit 2 - Everybody giving you advice in the thread thus far is pretty well spot on, calderp. Something I think you need to have impressed upon you is that engines are complex mechanical devices that operate under extremely adverse and challenging circumstances at the best of times. Engines are precision instruments, this goes triple for the rotating assembly. You MUST have proper surfaces, clearances, tolerances and specifications to allow an engine to last for any kind of appreciable life or reliability. Different parts of the same engine are different temperatures all the time, and the clearances have to remain such to allow it to last and function. The last thing you want is to have gone to all this trouble to do a repeat of what your friend who sold you the truck did. That ring gap was unreal. All that oil you were burning was doing the job of the compression ring, squeezing up in that gap and filling it so that the engine actually could even produce compression inside that cylinder.
Take your time, do it right and DO NOT be afraid to ask lots and lots of questions. Your intelligence is not in question here. Take pictures and keep us updated.
I'm learning from this thread a lot more than I have to contribute, but having done a few "deep" projects like you're doing, here's my 2 cents on cutting corners:
By default, don't. But if it's something that's not hard to replace later AND isn't likely to lead to other problems, then it's ok.
Pistons, internal bearings, rear main seal? Absolutely do them 100%; not a gram of skimping here.
Valvecover gasket and exhaust manifold gaskets? They're trivial to replace with the engine fully installed, and aren't likely to hurt anything else, so I'd say it's ok to leave them out of this build.
Undamaged/stretched timing chain and front main seal? Grey area. How much of your time is the $45 you'd save worth to you?
For seals, I've had good experiences with SKF, Victor Reinz, National/Federal Mogul, and Timken. I've used FelPro here and there and don't have anything bad to say about their stuff, either. Actually the only companies whose rubber parts I've had problems with are Karlyn and Beck Arnley, though I've never had a problem with anything else BA make.
Rockauto is a parts distributor, not a parts maker. They list the actual manufacturer in their catalog - anything from garbage made in Wheretheƒuckistan to OEM parts and better. Have I used them heavily for years and had consistently great experiences with their customer service in particular? Yes. Would I install something mission-critical just because they sell it? Absolutely not.
Just a question, why not buy a good running 22r, a 66$ engnbldr gasket set, put in the 22r block on your 20r head, sell the 22r head, and enjoy the slight torque increase and oem reliability? I mean, rebuilding an engine is better if done properly, and more fun, but I was just curious since money and time seem to be an issue.
Just a question, why not buy a good running 22r, a 66$ engnbldr gasket set, put in the 22r block on your 20r head, sell the 22r head, and enjoy the slight torque increase and oem reliability? I mean, rebuilding an engine is better if done properly, and more fun, but I was just curious since money and time seem to be an issue.
Maybe his situation is different but around here in the land where you can't escape old Toyotas 81-84 22R bottom-ends in good repair aren't exactly hanging out on every street corner. He'd also need to tweak or replace the 20R carb to get it running right. It's just enough of a displacement increase to matter.
As a beginner in a time crunch with a need for reliability over all else I think he's making the right call. Can always look on the local CL and see if you get lucky but a used engine can be a ticking time bomb and introduces an unknown variable. This way he knows what the condition is.
Well the car shop is uptown and my house is downtown and when it's Mardi Gras I don't even try going from downtown to uptown. But now Mardi Gras is over, so back to work. I plastigauged the bearing today:
Rod 1 - .0015-.002
Rod 2 - .003
Rod 3 - .0015-.002
Rod 4 - .002
Main1 - .002
Main 2 - .002
Main 3 .002
Main 4 -.002
Main 5 - .0025
They're mostly just on the upper end of spec (spec is .0010-.0022 for both rod and mains) but some are over. is it normal to have variations like that in the rod clearance?
Now I need to check the crank, right? Is this something I can reasonably do myself with a good caliper, or something I need to get the shop to do? I don't have a dial gauge for measuring runout. With the installed bearings the crank did turn very very smoothly without any spots where it was catching.
I do things a tiny bit different, but trying to explain it over typeface is difficult. This is a good video.
I wouldn't have a problem reassembling that engine with those specs if I had to, but cutting a crank usually isn't very expensive and bearings cost the same regardless of oversize.
Oh, thank Jimby, I just saw this. Journals mic'ed out ok, luckily. The mains have been ground .030 so it's polish it up or get a new crank. I think I've got it all sorted now except one last problem. I dropped the head off at a motor shop to get tanked and asked them to check it for me. They did and told me it needed shaving, but it's now .1" (maybe even .15", I haven't checked it with a really accurate tool yet) shorter than spec! Can I work with this, or am I going to have trouble with piston clearance or setting the timing? I'm kind of pissed that the shop shaved it and charged me $60 without bothering to check how much it had already been decked since this seems like such a huge amount.
I'm with 83. Used a shim on my last 20R without any problems. Some folks are scared of them for reasons unbeknownst to me. Probably heard horror stories from someone who didn't install it right. Ask your machinist if they recommend a shim or not, and for installation instructions.
Sorry, I should have been more thorough in explaining the problem. I did look for head shims and all I can find online is a .020 shim from either LCE or rockauto. Won't help much for my .100 problem, unfortunately. This is what had me concerned to begin with cause if .020 is enough deck for people to recommend a shim, then five times more than .020 seems like something to worry about. Would a machinist have access to a larger catalogue of shims, or is this something that would be made custom? That seems prohibitively expensive.
It does seem weird to me that the only shim easily available for a 40-year old engine known for hard use would be .020. Seems logical that there would be a lot of 20R heads out there that have been decked a few times, right? Maybe you're supposed to throw 'em out after a decking or two? Or maybe you can throw 'em right back on without worrying about how much it's been decked? I have no idea. I know that piston clearance and timing is an issue, theoretically, when you over-deck a head but I don't know if it's specifically a problem with the 20R. Hoping someone with more experience can weigh in on that.
This is something you should take up with the head shop that cut your head. I don't know the max that can be taken off these heads before chain slop and valve clearance can become issues. It's usually more than people think, but I do not have numbers. You can try searching this or other boards as well.
02-10-2015, 09:08 PM
