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Any tips on breaking in a rebuilt engine? Pages: 12

pettaw on Fri April 08, 2005 1:29 PM User is offline

I'm having the engine in my Volvo rebored due to piston slap when cold, and am fitting new big ends, and crank mains too. Standard sizes all, because I detected virtually no wear in the bearings, although obviously I'm going with new +0.37mm oversize pistons (+0.015")

Any tips on break in? Go gently? Drive it hard? Which type of oil, synth? Mobil 1, or plain mineral oil.

BTW: The machine shop seemed a bit sniffy about boring to the clearance recommended in the factory manual (0.01mm-0.03mm, or 0.004"-0.001" I convinced them to hone to 0.02mm clearance, and the guy was like, well, I think that's tight but we'll do whatever you want.

meaux on Fri April 08, 2005 1:52 PM User is offlineView users profile

Well, when I installed a new 95 302HO in my 85 F-150 (orig. 300/6), I was told to prime the oil pump, start it, bring it up to 3000rpm for 10 minutes, shut it down, change the oil, next day drive it as normal. After 16K miles, it's been fine, hadn't had to touch it.

This may not apply to a Volvo, as the 302HO has a roller cam. I think you should ask the Volvo folks......Volvos (to me anyway), are strange cars. Back in the 70's when they used carbs, the most foolproof way to ensure the car would start, was to stand outside the car, open the door, lean in, pull the choke lever, and turn the key. This was to make sure the gas pedal was not touched. I'm sure that is not the case these days.......:-)

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Lazy bum who lives off his wife.

01 BMW 530i Sport, 92 Porsche 968, 85 F150, 72 911, 08 GM SUV, 01' Ford Lightnin'

Karl Hofmann on Fri April 08, 2005 2:02 PM User is offlineView users profile

I would say that every person has his / her own ideas and theories on how to run in an engine. I tend to make good progress without revving it hard or labouring the engine at low revs, but to give it a wide range of revs, IE drive normally. Oil is whatever the manufacturer reccomends, but I would change it after about 500 miles

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Never knock on deaths door... Ring the doorbell and run away, death really hates that!

NickD on Fri April 08, 2005 4:50 PM User is offline

You are a decimal point off 0.0003937 to 0.0011811 inches is very tight for an aluminum piston that expands greatly with combustion chamber temperatures, would recheck that.

pettaw on Fri April 08, 2005 5:09 PM User is offline

Sorry, first measurement should be 0.0004. Yeah, it is very tight, but that's what it says in the book.
Oversize 1 -
Piston size- 89.27-89.29mm
Bore size- 89.29-89.30mm
Clearance- 0.010-0.030mm

I don't know enough about these things to argue with the official Volvo manual.

Any tips on breaking in Nick?


Edited: Fri April 08, 2005 at 5:10 PM by pettaw

NickD on Fri April 08, 2005 6:32 PM User is offline

I always numbered and hand fitted each piston splitting the clearance specification and using a piston feeler gauge, for your engine would use 0.0008" and not even look at the overall tolerance. It's important that all the pistons have the same clearance. Would plastigauge each bearing as well splitting the tolerance specification.

Always told new engines use break in oil, but never found that on the shelve so just used convention oil. You want the engine to break in and would stay far away from any synthetic oil. While some negative things were said about Quaker State, that has been my oil of choice for years, and yes a Detroit engine if properly fitted can go well over 300,000 miles. Would also do a static balance test on each connecting rod/piston assembly. A dynamic balance is desired, but very expensive.

I like to rotate the engine, first by hand to check for smoothness with the spark plugs out, no ignition connected yet, then run it with the starter motor with a battery charger connected. Valve covers off and crank for up to 30 seconds wait a couple of minutes for the starter to cool down and repeat that several times. With a manual oil pressure gauge installed, should hit full pressures with this test and can see the oil coming up lubrication the valve train. This also pumps up the hydraulic lifters if you have them. The starter should turn the engine without much straining. I have already had the block acid cleaned or baked clean and checked all the oil and coolant passages.

Feel the first hundred miles should be driven without excessively revving the engine, normally 3,000 rpm is tops, but a lot depends upon what it sounds like and how easy it cranks when hot. Then a couple of hundred miles of city like driving, then hit the highways after that. I have never used synthetic oil, but normally change it after around 1,000 miles depending on the color of the oil, but mainly the filter.

A lot depends upon how neat you are and how clean the insides are, some I let go 3,000 miles, then change normally. Have a lot to keep track of depending upon the quality of the work done, oil pressure and avoiding engine overheating are keys and checking constantly for any leaks, plus doing a sharp tune up. With a good job, all should go well.

TXAB on Fri April 08, 2005 9:43 PM User is offline

I agree with Nick. Balancing your engine (crank, pistons, rods) will make a big difference. I'd also suggest using a product put out by BG Products called Pre-Lube. It's great to use during assembly. Will stay on parts and not flow off. Especially great if you have to assemble your engine over a period of time. You'll be protected during any crank movements while assembling and starting. On all my engines I've re-built have always changed oil/filter at the 500 mile mark. I also analyze the filter, looking for any material that shouldn't be there.

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"Don't get stuck on stupid!"
---- Lt. Gen. Russel Honore

pettaw on Fri April 08, 2005 9:52 PM User is offline

Quote
Originally posted by: NickD
for your engine would use 0.0008"


You know what? That's exactly what I told the engineering firm to do! Split the spec in half- 0.02mm!. I've got a dial gauge and caliper so will be checking extremely carefully after it comes back. Checked a couple of big end clearances using Plastigage, used to the letter as in the book and seemed to be so well within spec, that I'm just using new standard main bearing shells, new standard big ends, and new standard thrust washers. Oil pump has done 125K miles so new oil pump too. Funny though, measured old spring and seemed about 1cm too LONG, supposed to shorten with age! somebody has been into this engine before me. Also, someone put double head gaskets on to lower compression to run on low octane unleaded. Head gasket didn't match properly, so they drilled holes in it....somebody has been into this engine before me.

Luckily head and block seemed unaffected by it and I had the engineering firm just skim off the minimal amount. Will also be checking head thickness when that comes back too, and if they overskimmed, they can expect bad words.

I'm expecting to spend this weekend cleaning and degreasing the insides before very carefully reassembling next weekend, if it all goes smoothly. Have bought new stretch bolts for big ends, mains, and head as well as full gasket sets and new seals top to tail. The way I see it, no point in spending loads of money on parts and then scrimping over a couple of 10 GBP oil seals and gaskets.

Intend to run semi-synth oil to break in, change after about 500miles and then run for about 10,000 miles to promote some wear before converting to Mobil 1 full synth.


Edit, I've also bought a small can of something called assembly lube, it looks pinkish, a bit like ATF, is this a good stuff to use? Seems so.

Edited: Fri April 08, 2005 at 9:53 PM by pettaw

NickD on Sat April 09, 2005 8:11 AM User is offline

What piston cylinder clearance does your machine shop want to use?

pettaw on Sat April 09, 2005 9:34 AM User is offline

the guy said normal clearance is about 0.0035"

Just got engine back, will be checking diameters soon.

Edited: Sat April 09, 2005 at 9:35 AM by pettaw

MikeH on Sat April 09, 2005 10:09 AM User is offline

I have rebuilt many, many race car and standard engines. I have never used a break-in procedure. When assembling the main, rod and cam bearings I use a mixture of half 30W oil and half STP applied to the bearing surfaces when I install them. There are commercial break in products that will do the same thing but at a much higher price. The first 90 seconds or so of an engine's life are critical. The initial startup pretty much establishes any bearing slippage and wear patterns especially if you do any reving which should be avoided at all costs for the first 5 minutes of engine life. It is so neat to hear that new engine rev up but please avoid the temptation if you can. After about 30 minutes of idle to make sure that oil flow is O/K you can drive as normal. The newer piston rings (oil) are much better than they used to be as well as the oils.

By the by, I agree with the .0035 that the machine shop suggested. It really isn't going to make much difference in overall performance as the rings will expand to accomodate if installed properly. Aluminum pistions really do expand as they get hot. The amount of expansion depends on the type of rod pins and the supply of water to the cylinder walls and head.

pettaw on Sat April 09, 2005 10:35 AM User is offline

Interesting, so you don't subscribe to the procedure of keeping revs at about 2,000 revs for 20 minutes after first start up to break cams in?

I've got some Comma "running in oil" from the machine shop, as well as assembly lubricant. Is this good to use, and when should I change to 'normal' oil. About 500 miles? and then when to convert to full synth.

NickD on Sat April 09, 2005 11:24 AM User is offline

We use to use as much as ten thousandths clearance on racing engines, but that is kind of history for todays cars. The average clearance today is more like one thousandths and ring gap clearances have also dropped substantially. Maybe your machinist is from the old school and hasn't kept up on emission requirements.

MikeH on Sat April 09, 2005 4:53 PM User is offline

Nick may be right about the ring clearance. I had my Explorer machined .002 clearance and hand lapped the bearings using Plastigage so I knew what I had. For some reason, I thunk that Volvo used looser tolerances. You know the Swedes - always keep the Yanks wondering. I still don't think you need break-in oil. Today's ring/bearing products don't really need any real break-in time. What type of assembly lubricant - GelLube, MPZ, E.O.S., Childs & Albert or some other? All are good. Be sure to also coat the cylinder walls before putting the pistons - keeps the walls from scoring if you start the piston in wrong.

pettaw on Sun April 10, 2005 3:06 AM User is offline

I got those clearances from the offcial Volvo service/workshop manual for my car, so surely I can only go by that: 0.010-0.030mm clearance. They even put the extra 0 in at the end for some reason.

The assembly lube I got was MPZ, it looks reddish, not unlike ATF actually. So this is good stuff to use?

Maybe I should only use the 'running in' oil for the first run up to temperature and the first run on the road, and then drain off straight away and put in a good semi-synth? Apparently some car manufacturers are so confident about their machining processes that they use Mobil 1 to break their engines in. I won't be doing that, but maybe semi-synth would be good.

Also, the intermediate shaft on this car does nothing except drive the rotor arm round and the oil pump gear, so how much strain is going to be put on it? I ask because there seems to be a slight nick in the middle bearing surface, either from dirt or possibly I scratched it getting the shaft out. I don't really want to take it back to the machining shop again. The shaft turns over really smoothly with no scraping or scratching noises, is it OK do you think? Or do I need to bite the bullet and take it back again? How much extra is it going to cost me to get the new bearings installed and line honed?

NickD on Sun April 10, 2005 6:49 AM User is offline

All measurements are made with dry parts, otherwise you are adding in the thickness of the oil, Would carefully insert a dry piston in a dry hole and use a piston feeler gauge. Don't turn the crank when checking the main and rod bearings with plastigauge.

Yeah, I talked to guys about assembling an engine using anything from talon to Roman chariot axle wheel grease, and ask the question, do you put that stuff in with every oil change? Talk about adding snake oil, just freely lubricate all the parts with the engine oil of your choice, wont' get into what engine oil is best, but not synthetic for breaking in. Course that could be a wives tale too, heard of guys changing engine oil in brand new vehicles before putting on a couple of miles and got oil burners, maybe they had oil burners for other reasons, I just don't use synthetic oil as I don't race my daily drivers.

Would pour on a half of quart all over the crankshaft with the engine upsidedown before installing the pan, you also want the oil inside the engine if you want to paint the block and pan, paint doesn't stick to an oily surface, same with the camshaft and rockers. Have the cylinders well oiled, but wipe the excess oil off the top of the piston, otherwise you will load your neighborhood up with smoke when you first start it.

Really can't comment about that nick in your bearing, but if it brothers you and will think about it a thousand miles up the road, would repair that.

MikeH on Sun April 10, 2005 9:33 AM User is offline

Nick is right about the nick. Fix it now or how much $$$ later? Nobody know the trouble you might see

NickD on Sun April 10, 2005 11:17 AM User is offline

Will never learn that, with my snow thrower engine, had to wait a week for the new connecting rod bearing to come in, when it did saw a tiny gap in the connecting rod cap where the old one put in a dent. The bearing has a thick steel sleeve measured true, and I convinced myself that by filling that tiny gap with a high temperature epoxy it would last forever. After all, ice cold air is entering the crankcase from the carb.

Forever was three hours of hard use, in that same exact spot, the epoxy had disappeared and the new steel insert was pounded right in that tiny gap and split into two pieces. Now there is a new connecting rod, piston, bearing, and rings in that engine, ha, so far it lasted seven hours and still going strong, but hopefully I won't find out again until next year. I am out four hours work and 15 bucks for the new old needle bearing, so I didn't cuss that much. But would hate to have to pull and engine out again. Probably would say the heck with it and push the car off a high cliff, LOL.

pettaw on Sun April 10, 2005 3:42 PM User is offline

Yeah, you're right. I'll get the machine shop to install the new bearing shells, and then hone/ream them to the correct clearances.

I think I'm going to use the 'running in' oil just for the first start up, cool down and then the first run, and then drain to get rid of swarf, then put Castrol GTX Magnatec 10w-40 in which IMO is a top quality semi-synthetic. I'm still in two minds as to whether to use any assembly lubricant on the bearings at all, or whether just to use plenty of clean oil.

Thanks anyways. Hopefully it won't be too big a bill for the machining. Close to 2000 USD as it is with all the new gaskets, and stretch bolts, pistons, con-rods etc.

MikeH on Mon April 11, 2005 1:06 PM User is offline

You shouldn't feel too bad about the cost. When I rebuilt my explorer the cost for machining, all new parts including oil pump, timing chain, lifters, injectors, etc + Borla Heeaders was over $4,000.

NickD on Tue April 12, 2005 6:49 AM User is offline

In 1958, I had my 54 Olds bored out 1/16" oversize, crank turned, all new valve, piston, lifters, plus parts to rebuild the carburetor, starter, generator, new front end parts, brakes, paint for the underhood, and engine block with a static balance. The total bill when I was done doing the labor myself with exception of the machining came to $146.00. But the firewall forward was all brand new. My peers told me I was crazy putting that kind of money in an older car, but I liked the 54 Olds, and wouldn't be caught dead in the overly burdened chrome monsters they came out in 1958. I also dechromed my 54 and it was a real head turner at the time.

Today, $146.00 won't even buy a cracked headlamp lens.

MrBillPro on Wed April 13, 2005 1:46 AM User is offlineView users profile

Man in 1958 I was 7 years old dreaming of a 55 Chevy, and I got one in 1965 when I got my drivers license at 14 years old man that was a nice ride wished I still had it never had any a/c problems with that car it didn't have any a/c.

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Don't take life seriously... Its not permanent.

NickD on Wed April 13, 2005 5:27 AM User is offline

It was either in 1955 or 1956 that Chevy introduced AC and back then it darn near doubled the price of the car. A fully loaded 56 without AC ran about $2,700.00. I drove a 56 a short time ago, swore my hands were spread out like on a cross putting them on the steering wheel. Did overhaul several 265's and 283's, first thing was to pull the factory studs that were press fit in, and get threaded ones that screwed in.

Also the castings on the Chevy blocks was crude, lots of flashing left in the lower crankcase, but as long as they cleared the counter weights by a fraction of an inch, they left those on, use to break those off. The combustion chambers in the heads looked like creators in the moon. The Buick and Caddy blocks at the time were much cleaner with machined combustion chambers, but were not supported by the aftermarket, had to get a 283 block if you wanted to buy aftermarket goodies, that never made sense to me.

Can't quite recall the AT in the 56, but do recall the 55 had a two speed Powerglide, a really slow gear plus and almost as slow gear. The Olds, Buick, and Caddies had four speed Hydramatics that you could drain off a couple quarts of AT fluid and really get some quick start offs from the line.

Lets see, in 1955, think I was two years old at the time.

MrBillPro on Wed April 13, 2005 1:59 PM User is offlineView users profile

Quote
Originally posted by: NickD

Can't quite recall the AT in the 56, but do recall the 55 had a two speed Powerglide,

Nick, Mine was a 3 speed on the column and I took a 4 speed out of a 64 chevy impala from the junk yard, new car had just been wrecked"on the floor" and I put tranny shifter shift on the floor, tranny was like new and I put that behind a rebuild 283 bored 30 over about a 288 CU. IN. 4 barral carb and hooker headers, mallory duel point dist. and I changed my ring and pinion to a 411 that thing would scoot about 13.00 to 13.5 seconds in the 1/4 mile but now gas milage was terrible but at 26 cents a gallon and gas wars at 23 cents a gallon it was no concern.

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Don't take life seriously... Its not permanent.

pettaw on Sat April 16, 2005 3:54 AM User is offline

Well, the machine shop came back to me, they said the intermediate shaft bearing shells that I ordered from Volvo are unfinished and require boring, so they have to do that and it'll cost another 110 GBP, approx 200USD?

Still as you guys say, its not worth putting that much money and effort into it to scrimp over something that might well give trouble in the future.

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