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What to check/prep on an unknown engine ?


egret

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I have some questions for the depth of accumulated knowledge here.

To set the scene, I've recently picked up a mk3 1300 engine which I'm told ran before being pulled from the rather rotten car. It had a gearbox with overdrive attached, and I bought an oil cooler which I assume came with the car. The clutch friction plate and pressure plate both look new. Under the rocker cover the front of the assembly is quite black, the back not so much, I'm not certain if this is just from sitting (see image). I think this is everything I know about it!


The aim is to get this into my (currently 1500 engined) spitfire without doing a full engine re-build.
So my plan is to do the following:

Check plugs
check main bearings
check thrust washers
check big end bearings

check for rocker play then set the valve clearances
Swap oil pump with the on in my 1500 unit as it seems to be working well and I believe the pickup and capacity are better than the 1300 one.

So what things would you check on an unknown engine? What have I missed? 

I've deliberately not mentioned pulling the head off.  I've suffered with headgasket failure before on my 1500 from poor gaskets and heard rumours that payen gaskets have dropped in quality, so I'm currently of a mind to leave the head on. What items can (and should) I swap from my 1500 which I know for the most part to be good.



 

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Egret,

No doubt, you will get a range of opinions, so here's mine!

Your plan of checks falls little short of a rebuild, if you intend to take off the bearing caps and inspect them, and you have the engine on the bench anyway, so reconsider and bite the bullet of doing it completely?    That plan misses the opportunity to inspect the bores, as you don't want to remove the head (I think you are over cautious about Payens!), and failing rings might be a cause of the blackening at the front.   You can't really do a compression test on the bench, although I suppose you could fit the starter, charge up the battery and take a brave pill!

I'd remove the rocker gear competely, as that blackening could be a sign of poor rocker lubrication - it all comes from the rear, and the front rockers suffer first. Look inside the rocker shaft, the normally low oil flow means that all the grot falls out inside it, and lowers the flow even more.   With the gear assembly off, you can inspect the rocker faces far better for pitting.

Good luck!

John

PS do you have an engine stand?    Good investment, even if you do intend only a limited inspection.  J

 

 

   

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Thanks John,  I suspect it all boils down to each individuals appetite for risk and perception of the quality and state of wear of old parts vs the uncertainty of the new offerings!

It is now on an engine stand, an extremely useful thing.  Reinstalling the starter motor and connecting a battery is something I hadn't considered.

Removing the rocker gear is a good idea, and thanks for suggestion on possible oil starvation.  The issue with a full rebuild is that I'm trying to avoid replacing anything which I don't have to.  I'd love to do a full build and balance, but for now I don't have the resources.  It also seems like there's such a range of quality in parts that following an "if it aint broke" (and won't catastrophically break everything) mindset seems the lowest risk.

 

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I've bought old triumph 4 and 6 cylinder engines of unknown condition in the past. I just checked the crank end float, see how the plugs had been burning. After lubing  the bores with engine oil, I turned them over by hand to make sure there were no noises and not binding. Changed the oil and filter, and took a chance and installed them. Both ran ok. Difficult to gauge how good an engine is until it's hot and under load. 

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Egret,

Maybe I'm affected by previous experience!   When I acquired SofS, it had a 'race prepared' engine in it, with golden oil in the sump!    I knew nothing of the engine, but it seemed not to need a strip down, indeed that it had never been used!   So I used it, and we took it to a test day.    Got back from first stint and the tappets were rattling so Chief Engineer adjusted them.   A second stint and they were rattling worse!   I had great confidence in the CE so we withdrew, and went home.   And stripped the engine.

All, but ALL the camshaft bearing bores - it was 'race prepared but still with the camshaft running in the bare block - were worn to buggery!!!   The block was scrap, the wear was too great even to line bore and refit cam bearings!   The cause was that the DPO had fitted JAGUAR valve springs, at least twice as stiff as standard Triumph springs.  The extra stress had been withstood by the cam followers and valve train, but had just been too much for the poor Triumph block!

Now I ALWAYS strip an engine that is new to me.

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the rocker gear does and top of the head looks very grubby. That looks like very old oil so doesn't bode well if thats an indication of how its been maintained......
If it was mine I would take the rockers off and check for wear and take the head off and check the bores. 

mike
 

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I drained the oil, which was black and with a mild whiff of petrol, but no sign of coolant.  I also checked the plugs which were all pretty black, sooty, and eroded.

I took the rocker gear off but haven't had the time to inspect the rocker shaft.  This is a photo of the front most rocker (furthest from the oil supply) and it looks pretty worn to me.  It's probably somewhere around a 1/2mm recess worn into it at the worst point.  Also I just noticed that the screw to locate the rocker shaft in the first pedistal is missing.  Could this cause oil to come out this hole and not make it down the shaft causing the starvation issues?  I'll check for wear on the shaft and look at possibly replacing the badly worn rockers.  Maybe just swap out with the rocker assembly from my 1500 if that's possible.

I'll update when I've got the sump off and had a look at the bottom end.

 

PXL_20231011_073049401.jpg

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2 hours ago, egret said:

I took the rocker gear off but haven't had the time to inspect the rocker shaft.  This is a photo of the front most rocker (furthest from the oil supply) and it looks pretty worn to me.  It's probably somewhere around a 1/2mm recess worn into it at the worst point

Not great, but I have seen worse. The bigger issue is wear on the shaft which if left too long causes wear on the bores of the rockers themselves which is an issue as it messes up the oil supply. And makes everything much noisier.

3 hours ago, egret said:

Also I just noticed that the screw to locate the rocker shaft in the first pedistal is missing.  Could this cause oil to come out this hole and not make it down the shaft causing the starvation issues?  I'll check for wear on the shaft and look at possibly replacing the badly worn rockers.

Most definitely...

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1500 rocker assembly is identical, straight swap, definitely the one you have there has seen better days.

For the head gaskets, I don't know if what you're saying about quality applies to the non-recessed gaskets used on the earlier engines. How recently did the quality drop? In 2018 I used a reproduction Payen one in our Mongol Rally car, it didn't fail, and we definitely pushed it harder than most ever will, although compression of that engine was a bit lower - about 8:1.

I was advised by a certain former forum member that the single layer asbestos type ones (made by Coopers?) are the best for a 1300. If you search on evil bay you might be able to find ones cheaply (they look like this, price is way too much - https://www.ebay.co.uk/itm/162791637476). I have several of them in storage, but I'm sticking with the new Payen ones for now, I used a NOS gasket once before and it failed instantly (although that was a different type - Payen copper asbestos steel sandwich).

By the way, you're correct, 1500 oil pump is quite a bit bigger, and has a pickup with a strainer, but extra capacity won't help you much if your bearings are shot. I think there's nothing else besides the rocker gear that might be worth swapping. If it ends up that the head is bad, you can fit your 1500 head but it will need a substantial skim (from memory over 60 thou). 1500 has slightly bigger inlet valves too... Don't swap over the water pump, the pulleys are a different size and the 1500 one will spin too fast.

Unfortunately, I feel like you might end up taking the whole thing apart, at least if those black deposits on the rocker assembly are a sign of worn out valve guides. In for a penny, in for a pound...

Edited by JumpingFrog
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On 10/10/2023 at 2:58 PM, egret said:

Thanks John,  I suspect it all boils down to each individuals appetite for risk and perception of the quality and state of wear of old parts vs the uncertainty of the new offerings!

Exactly this. I usually whip the sump off and check/renew bearings and oil pump. Maybe timing chain/tensioner also. I’ve also tended not to pull the head off provided all cylinders are producing noticeable compression when turning by hand and not too much hissing from the ports in the process.

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@egret my two penn'orth: the suspect Payen gaskets were/are the recessed bore type, so probably not too much of a concern. However, I did recently have a bit of a head gasket weep after a hasty head removal + replacement on a new Payen. That would be the third or fourth in the last 4 years (on two cars, much messing about) and the only one that gave trouble, so it's most likely my slapdash rebuild to blame. 

This summer I couldn't find anyone with 1300 Payen gaskets in stock so plumped for NOS Unipart headset off eBay. Following Colin Escadrille Ecosse's detailed guide (below) I fitted that in August and it's just survived the RBRR with no sign of leakage.

If it was me, I'd take the head off. But understand your reluctance. 

 

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The sump came off last night.  Main bearing cap removed for inspection and looks ok to me.  The bores look ok too from what I can see below the piston skirts, however I'm pretty sure I could feel play when roking the most oil starved valve in it's guide, so I think its probably in need of new guides.

So this means existing head off, and rebuild my spare "big valve head" stamped 218141 which I belive is 8.5:1 on a 1300.  I don't currently have valves for this head so I'll need to get those, maybe new guides, unleaded seats, and get the valves multi angle cut.  Given that this head would drop the CR from the stock 9:1 of the engine, maybe I should have it skimmed for what CR I want to run (maybe 9.5-10.5? I'm running high octane stuff anyway to avoid ethanol) and checking piston popup and levels etc. https://www.teglerizer.com/triumphstuff/spitheads.htm gives advice on depth of skim.

One other observation is that I can turn the engine over (with the rocker gear off, so all valved closed) rather easily with only one hand on the front pulley, and I'm more the build of a racoon avatar than an ape!

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Egret,

You're worrying about piston popup and that your CR will drop with another head, so you're clearly wanting performance. Sorry, but a 'that'll do" attitude just won't do!

That main bearing looks as if the crank has been wobbling from other loose bearings.   Never use other sites to guess at CR, or trust that nonprevious work has been done, Measure your chamber volume, and calculate   the required skim, especially if you are aiming at 10.5 which is the highest you can use with pump fuel!

See my article ("How to skim your head") several years ago to see how!

John

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That bearing looks pretty good for the bottom half of the centre main - it takes the most thump. Copper just showing on one edge, so wants replacement really but crank probably still good.  Of course they may well have been replaced before. Pop the bearing out and see what make and whether there’s an undersize marked.

Compression…. If the engine has been sat for a while then rings may be stuck, but would probably free off with a couple of heat cycles / dosing with ATF.  Little bit of rock in the valve guides…. Meh…

Depends what the ultimate goal is? Standard 1300 will feel a bit limp after a 1500 due to the substantial drop in low-end torque, especially if the car is on 1500 gearing (3.63 diff). Is this to be a stop gap while a 1500 is rebuilt or is it the intended end-game?

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On 10/10/2023 at 12:36 PM, egret said:

I've suffered with headgasket failure before on my 1500 from poor gaskets and heard rumours that payen gaskets have dropped in quality

I've heard similar things, however I run a 1500 built in 2020 to "fast road" spec. CR is 10.2:1 and I haven't (so far) had head gasket issues apart from trouble sealing the oilway at the rear of the head (it weeps very slightly). I've put a few thousand easy and hard miles on the engine (most recently the RBRR, checking history indicates about 5.5k miles since the engine build) - so my anecdotal experience is that the payen gaskets are "good enough". (I used ARP studs and nuts for the build)

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I'm doing the silly thing and not defining the brief before I get carried away with fears of exploding engines and dreams of horsepower :laugh:

The end goal is for this engine to be build to a good fast road spec for the car.  I have aspirations of light trackday work, but really I want something with a bit of reliability so eeking every last bit of power isn't what I'm after.  With that said I'm not looking to reach the end goal just yet.  I don't have the time or money to do it justice. 

A low expense rebuild (ideally without too much abortive cost) that allows me to run the engine for a year or so to confirm it's not a lemon is the target.  I'm not going to change the camshaft or do any major head flow work,  just unleaded valve seats, a skim, and hopefully some fancy 3 angle valve seat cutting.  Replacing the bearings, maybe upgrading to duplex timing chain, then get the new head on are about the limit of where I'm going.

To get there will require a fair bit of measuring and checking.  I need to get the pistons and combustion chambers measured to check compression ratio to specifcy the skim required, check the bearing sizes so I can order replacments of the correct size (tri-metal).  Check the timing chain and tensionser and possibly replace/upgrade with duplex ready for a new cam in the future.

All this has just been slightly derailed becuase I can't get the conrod caps off so can't check what bearings are in there.  Main bearings are marked VP 4921  & 140111 which I think is standard sizing, so that bodes well.

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42 minutes ago, egret said:

The end goal is for this engine to be build to a good fast road spec for the car.  I have aspirations of light trackday work, but really I want something with a bit of reliability so eeking every last bit of power isn't what I'm after.  With that said I'm not looking to reach the end goal just yet.  I don't have the time or money to do it justice. 

A low expense rebuild (ideally without too much abortive cost) that allows me to run the engine for a year or so to confirm it's not a lemon is the target.  I'm not going to change the camshaft or do any major head flow work,  just unleaded valve seats, a skim, and hopefully some fancy 3 angle valve seat cutting.  Replacing the bearings, maybe upgrading to duplex timing chain, then get the new head on are about the limit of where I'm going.


Just my two cents, but, I wouldn't worry so much about the duplex timing set right now, the simplex timing gear on the 4-cylinder is adequate, it isn't a thing I'd prioritise spending money on until you fit your new cam. By all means throw a new chain on it if it's slack though, but you'll have to contend with the front pulley nut first, and they're usually well and truly tight.

If you want reliable and low-expense, it's probably best not to change much, just what's worn. On the flip side, if you're thinking of track use, I would start by thinking about balancing and maybe tuftriding the crank. Watching with interest either way, I like these engines.

Edit: Get in touch with https://the-chain-man.co.uk/ if you want a decent timing chain, the Rolon ones on sale are a bit rough. If you want a decent tensioner though, I can't help, I also need one.

Edited by JumpingFrog
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42 minutes ago, egret said:

The end goal is for this engine to be build to a good fast road spec for the car.  I have aspirations of light trackday work, but really I want something with a bit of reliability so eeking every last bit of power isn't what I'm after.  With that said I'm not looking to reach the end goal just yet.  I don't have the time or money to do it justice. 

A low expense rebuild (ideally without too much abortive cost) that allows me to run the engine for a year or so to confirm it's not a lemon is the target. 

This is a good clarification. In which case, it wouldn't be totally daft to leave the bottom end as-is, and also leave the head undisturbed. New main and BE bearings might be sensible but from your photo I wouldn't say it was chronic. Big ends might be a different story though. What's the crankshaft end-float like? 

Your main bearings are standard size Vandervell which does bode well. No way of knowing but they could even be original - especially if the cylinder bores look in good condition. 

I don't think there's such a thing as "light trackday" driving but maybe others can resist temptation to thrash! In my limited experience it's perfectly possible to do a home rebuild and come up with a fun trackday engine which is also reliable. Balancing the rotating + reciprocating parts is worth the effort when you get to that stage. 

One other thing - duplex timing sets for small crank engines seem very thin on the ground. Maybe they're back in stock now but I couldn't find any last year or year before. So if you see one, snaffle it and save for later. 

Edit: JumpingFrog makes a good point about duplex vs simplex - my cars are both simplex. I would have gone duplex on the Spit if I could find one - new chains have a mixed reputation. But I haven't had any issues so far. 

Edited by PeteStupps
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