Inspecting engine repairs

[mblake4u]

Hi All,

I'd like to know what checks would be good for an engine that's been repaired. I was having problems with my engine (no compression on one cylinder and then a blown gasket or water jacket) so I took it in for repair and I should be getting it back soon.

Apparently the van drives like a dream now but I'd like to make sure before I hand over the cash.

I was thinking the following things would be good checks:

1. Start the engine from cold to make sure the choke's working and it idles OK.
2. Check the timing they've set.
3. Take it for a drive till the engine is properly heated up.
4. Take out the spark plugs, check their colour etc.
5. Do a compression test.
6. Check for smoke coming out the exhaust.

Can anyone suggest any other checks I should do to know the engine's OK?

Cheers,
Michael

[Hacksawbob]

allow system runing up to temp so rad fan comes on. However this is not a good idea on a recon engine if it involves pistons/bores they need to bed in at 'normal' operating temperatures and rev ranges not over rev or prolonged sat at idle. so you cant really test over heating situation it is only possible in use. 1000 mile run in should tell you if there are problems a good engine builder/fitter will allow you at least this or 1 year to test it out.

but yes drive it for half an hour and look for dripping oil/coolant is best bet after that get a written warranty and pay with your credit card so you have some come back

[HarryMann]

Depends what they've actually done to repair it... what was originally wrong to a large extent.
Compression a good idea, plug colour (but don't let it idle, do a plug 'chop') for a good idea.

If it's had new rings, then that's another question, bores should have been glaze bust or cross-hatch honed... don't use fancy oils for the fiirst few hundred miles at least. So if so, should load it up in stages to get them to bed in. Wiki should have some running in practices written up

As Bob says, make sure both the fans stages are coming on if its got two, by shorting the pins. Change oil and filter after say 500 miles. Make sure air filter is OK.

[kev mc]

to be honest with you most garages wont let you take the vehicle away without getting paid. if they have done engine work then they should guarantee the work they have done, and supply the manufacturer of the parts guarantee, but this will be with limitations unless a complete engine rebuild has been performed. from the other side of the coin (and deffo not saying you) some people really do not know how to treat a fresh build/rebuild, even after detailed explanation. i have had customers return with air cooled motors and "all they did was turn the screw on the carbs a little to make it run better"
if you trusted the garage, which i guess you did as you took it there, then trust there guarantee, listen to there advise on running in.
good luck with it.
kev

[mblake4u]

Hi All,

Thanks for the advice. I took it for a drive and warmed her up, then checked:

Started well from cold, idled nicely, no smoke from the exhaust.
Didn't quite do a plug chop but the plugs were a decent colour. I'll check them again after a longer run (they replaced the newly bought 4 terminal Bosch 'Super 4' plugs with your standard ones so I'm going to set the gap on them soon).
Compression test was interesting (checked each cylinder twice):-
Cylinder 1: 125 & 150
Cylinder 2: 150 & 125
Cylinder 3: 125 & 125
Cylinder 4 125 & 140
No obvious oil/coolant leaks (but I'll have a look under the van tomorrow morning)

I would love to be able to say exactly what they did but these guys aren't very good.. first of all I don't trust the main point of contact. He always has a storey and an answer to everything... The reason I went back to them was this was where the reconditioned engine came from (last year December) and I thought they may take some responsibility as the engine was only just out of warranty when I took it back to them. Anyway, long storey short, they took the engine apart fixed the head gasket (or water sleeve) and the compression on cylinder 1. I know there was a broken stud.

This is what I've been told was completed but I think it should be taken with a pinch of salt (and they've probably added in some things to justify the price):

Remove & refit engine
Strip engine / assemble
Remove broken stud
Big end bearings
Cam followers
Rebored sleeves
New rings
2x recon cylinder heads
Gaskets, oil, coolant, plugs, oil filter

[HarryMann]

Rebored sleeves...

Is that overbored ?

Thus needing new (larger) pistons (not listed)

Cross-hatch honng would be expected, not reboring unless badly scored or heavily stepped at top ring

Pressures look OK, but certainly not great. They should be more consistent too, what is your technique.

Were the 1st and 2nd pressures taken on each cylinder sequentially, or all 1sts and then another go a round the whole engine for the 2nds? All plugs were out I take it. Throttle open or throttle closed?

Rgds

[mblake4u]

Hi,

Thanks for the reply. As I mentioned, I don't particularly trust these guys so he might have added some things in to justify the price. Cross-hatch honing vs overbored - I expect these guys would use the term interchangably.

Yes, I was a little surprised to see the values vary so much. I went round and checked each cylinder once and then went round again for the second values. I held the compression tester to the cylinder (all plugs out) and my friend gave about 3 turns of the engine each time. I'm not sure whether the throttle would be open but I assume it was closed - I can check with my friend.

Not knowing a lot about new engines, I was basically checking that there was compression on all cylinders and that it was better than when I took it in (roughly 110 on all four except for cylinder 1 which was 45). I was thinking that I also need to run the engine in a bit to get proper values - am I right?

I would like to check the pressures again, gap the plugs and just check things over again at my leisure.. rather than parked outside on the street..

Regards, Michael

[HarryMann]

Yes, depending on what was done, the pressures would increase for a while early on.. though developing good pressures does require running under high load from time to time, unlike many notions of running in lightly.. its a matter of igh load and cylinder pressures without local overheating, in stages. See 80-90 Wikipedia...

Well compared to 110's and a 45 psi, they seem to have sorted the problem
...as they are now probably all around 150.

I'm sure you have an engine that will idle nicely now (a good guide) and pull a lot better, with reasonable economy.

Here's a post about running-in new rings or pistons from the 80-90Tech archive 3 years ago

http://archive.club8090.co.uk/viewtopic ... ilit=honed

"My engine builder used to say "drive it/ride it like the throttle cable is down to a single strand"

He was wrong then...

It'll never run-in like that and probably glaze the bores... you need pressure and increasing heat, till it will stand full heat after say 1,000 to 1500 miles or so.

As said above correctly, if the bores have been properly cross-hatch honed, and the pistons and rings are correctly sized (check the ring gaps as per works manual down the bores at various places, to give an idea of bore wear and profile) then all will be OK

You couldn't drive an NA Diesel on a whisper of throttle everywhere anyway.

Drive it normally, but gently to start with... but with these provisos:

Heat is a function of throttle position and time...

Heat it can stand needs to be gradually extended, not gently for 1000 miles and then everything

So, can use plenty of throttle for a few seconds initially to get moving, then back off... so it forces rings out so they actually bed in.

Extend the time at larger throttle openings over a period of 500 to 1000 miles, from a few seconds to start with to a minute, then to a couple of minutes etc

Don't cruise at a large throttle setting for long to start with, go up to 50 ior so then lift off and let it settle where it wants with your current level of throttle, say 1/4 or 1/2, or 3/4

Don't use full revs to start with, but quite early, you can for a few seconds if it wants to rev freely, then tens of seconds etc

To restrict heat up hills change down earlier and go up on a lower setting, in,lower gear more slowly

Don't be frightened of it, if you feel you're pushing it's capabilities, lift off and/or change down..

The things to be careful of early are not around town, but on the main road or M-way, try to avoid M-way for a few hundred miles, as this is a low powered engine and always will have to work hard... take the A road.

If into wind or on a climb on M-way, be very aware of the load (throttle position) and every now and again back off for a minute or two where possible and then get back up to speed gently, use downslopes to build up speed and then see if she's happy to hold it on the level...

But every now and again, use some throttle to accelerate briskly, and as time goes on for longer and longer... to start with zip up in 2nd and then 3rd and then take it easy in top... then after a few hundred start giving it a minute or two of good acceleration in top (if that's possible!)

Do not worry too much, just keep it spinning and don't labour it toomuch or for too long, keep changing down if worried, steady as you go, accelerate and then back into top - modulate the throttle, a minute at one setting, then a minute at another. Let it build up speed if it wants to... but don't hold foot on floor for very long till a few hundred miles...

Don't carry heavy loads if you can help it to start with.

Don't idle it for more than a minute or two very early on - drive it or turn it off!

Change oil at 2 or 3 hundred miles, then after another 500 and then after say 1000 and that should be it. Use good quality diesel mineral oil up to 1,000-~1500 miles. Change the filter every time you change the oil

Provided it's been honed and you don't 'drive like there was nly one strand of throttle cable left', it will soon be going quite well.

Remember, accelerate briskly in the lower gears but change up earlier than usual

Good luck, there should be few hard and fast rules, you have to drive along with the rest of the traffic, it's just hills and M-ways that are a challenge at the very early stages, so avoid where possible in such a low powererd and heavy vehicle. Make sure tyre pressures are corerct too, so it rolls along easily.

I ran a set of rings in nicely in one weekend, but it was a 1,000 mile weekend... it was going rather well after 500 miles!

[mblake4u]

Hi,

Thanks for the reply - there are a lot of things to take into consideration. But I think I get the gist of it.

Just to confirm some of the things you've mentioned, when you talk about heat, you're talking about localised heat of the sleeves, rather than the overall heat of the engine as measured by the temperature gauge. Obviously sitting in idle in heavy traffic or labouring up a hill on a hot day would be bad - is that right?

This may seem like a really basic question, but I'd just like to make sure I'm on the right track.. Can you describe the feeling when the engine's struggling and you should back off the throttle?

You're right, the engine is running much better. I've noticed the change in the tone of the engine as it accelerates - it sounds so much nicer (if I were to describe it; smoother, higher pitch, less clack clack clack or put put put).

I'm supposed to be going on holiday this weekend and would love to go in the van - it's about 300 miles away but it's on the motorway and there's a horrible section where it's up and down hills for quite a stretch. I'm happy to take it slowly and I can force myself to alter the throttle position on the level but I'm worried about the hills - I know I'll have to drop to third and even second to make it up them without labouring.. there may be an alternate route but unfortunately maps aren't going to tell me the gradient of the roads. I guess what I'm asking is if there's a way to tackle these hills or should I just go away in another car..

It would be great if I could make it there, do my first oil change, potter about there for a week and then make my way home. I'll be getting up to 700/800 miles by then..

Regards,
Michael

[HarryMann]

when you talk about heat, you're talking about localised heat of the sleeves, rather than the overall heat of the engine as measured by the temperature gauge.

Yes exactly, heat in the cylinder walls, rings, piston cron etc etc.

Load... really this translates to cylinder pressures too, require to bed the rings in, no pressure they don't bed

===========

Yes, whilst loading up the engine to accustom it to pressures and local heat, do it for short periods and then progressively longer. If at any time you feel it really is labouring (typically this is into a wind (& particularly when you aren't aware of it) or up hills (when you should be aware), then back off and if necessary go down a gear.
The accelerator pedal is almost a direct guide to load, so if its down a long way and vehicle not accelerating, think why. Hill, weight or wind, and until its nicely borken in, give it a break so the heat can be dissipated and the revs and load change a bit.

Don't be afraid to use brisk acceleration. In fact, mostly drive normally, just being aware that you should be progressively upping the length of time its under load... for the first few hundred miles.

After all, even a fully run-in engine, shouldn't really be laboured at max load for long periods, unless you have prepared it for it.. by breaking it into that over thousands of miles and you know that everything is spot-on... esp. ign.timing; mixture; cooling system, lubricant temperature and pressures.

Anyway, doesn't sound like your engine has been completely rebuilt, so enjoy you trip, just if she's not flying up those hillz in top easily, then come down a gear as the speed falls back and ease it over the top. Good to let the speed build up down the other side too... loosen it up on a lighter throttle and let the speed drop toward the top of the next rise. Here, we see so many backing off ('cos of speed limits) down a long hill and then gunning it up the other side... complete opposite of what should be doing for economy and engine life. I call that the Rover driver syndrome, or did....but today modern cars and engines take it all in their stride !

[mblake4u]

Well I took her for the drive and she did quite well, except she did get really hot during the middle of the day.. and at times there was a headwind and hills, but I took a break when she got hot and waited till later in the day finishing off the journey at night. She's running very well when she's cool so I'm going to double check the cooling (also going to find out if it's possible for the fan to blow in the wrong direction) and then go over the timing, mixture etc.

Thinking about it - do you know what it means when she starts to get hot and then the oil pressure light flickers when you're changing gear? I'm thinking I should change the oil soon (as if I'm running her in). Maybe I should go for a higher viscosity (but I'm not sure what's currently in her). I suppose I could figure it out through trial and error.

Thanks again for your advice,
Michael

[HarryMann]

The oil pressure light flickers when you're changing gear?

They don't have oil pressure lights, do they... ? They have VW'ss DOPWS equivalent

Could you please describe your van, year, type, body, engine size, type etc... completely. I am confused what you are driving, thanks

[mblake4u]

Sorry, I assumed it was a simple oil pressure sensor.

The van is a camper conversion, T25, 1984, 1.9l (although the engine block says it's a 2.1l DJ).

I've attached some pictures if that helps..

IMG_20111221_102654a.JPG

IMG_20111221_102624a.JPG

IMG_20111221_102705a.JPG

Thanks again, M

[ghost123uk]

Well I took her for the drive and she did quite well, except she did get really hot during the middle of the day...

Do you mean the temperature gauge showed that it was "really hot" ?

Thinking about it - do you know what it means when she starts to get hot and then the oil pressure light flickers when you're changing gear?

Yes many of us know what that means and it ain't good I am afraid. If it comes on when the revs drop it usually means the big ends or main bearings are shot

I'm going to double check the cooling (also going to find out if it's possible for the fan to blow in the wrong direction) and then go over the timing, mixture etc. I'm thinking I should change the oil soon (as if I'm running her in). Maybe I should go for a higher viscosity (but I'm not sure what's currently in her). I suppose I could figure it out through trial and error.

In view of the oil light issue, I would not touch ANYTHING as they might use that as an excuse to get out of any guarantee !

Would you agree Harry ?

[HarryMann]

Yes.

Best thing though is to connect up a proper mechanical oil pressure gauge to an oil pressure port, and check the actual pressures, hot (80C)/cold (15c); idle 2,000 rpm.
Compare to book values... and the oil pressure switch settings