Jump to content

Engine upgrade questions


Recommended Posts

Alternative to chalk and specialist products is a cheap pack of talcum powder from Poundland or market stall. Stuart suggested this when I had trouble tracking down a fuel leak and I've used it ever since.

 

Hi Brian,

now could you imagine me using a cheapo Poundland pack of talc on an aeroplane :P

 

It would have saved a fortune for BA.

 

Roger

 

PS - excellent idea.

 

It's a great idea guys, just as it was at post number 16...lol.

 

Mick Richards

Link to post
Share on other sites

Again, thanks to your input guys, we have an update:

 

Main leak cause is the head gasket! Either it's most broken at the rear lhd side, or that's where most of the leak piles up and gets down the block and onto the clutch housing, but that's the main issue. Also, the pushrod tubes get leaky as well as rocker cover gasket, then it seems that the sump gasket is rubbish, but also it seems like there's a sweat around the three bolts on the block in the oil gallery...

 

So, head is coming off this week, and then a decision is to be made - what's the state of the bores, what's the state of the head - just slight skimming, new valve guides and lapping valves or a full rebuild, perhaps porting...

 

With the baby powder, the car does smell now more of my baby boy's bottom and less of nasty oil, which is not such a bad thing :)

 

Cheers guys!

Link to post
Share on other sites

Rear left hand side is where the pressurised block oil feed upwards to the head and rocker shaft is, I've never had an oil leak come from there but as you say if a head gaskets gone in that area it could rupture the seal around it and you would have a severe leak if so.

 

Mick Richards

Link to post
Share on other sites

Alternative to chalk and specialist products is a cheap pack of talcum powder from Poundland or market stall. Stuart suggested this when I had trouble tracking down a fuel leak and I've used it ever since.

...and some folks use one of those sprays for althete's foot that goes ona s a dry white powder as an easy-to-source and easy-to-apply alternative for tracing leaks.

Link to post
Share on other sites

God know when was the gasket last replaced (or if ever), so i guess a head-off is a must.

 

Is there a sign on when to change the timing chain and sprockets - without removing the cover - like a ringing noise or something - or should i do that as i have absolutely no idea about its history? (i guess 4a is not an interference engine?)

 

Also, is there a way of removing the cam followers and inspecting cam lobes with just the head off? If so - does it make any sense replacing the followers with somewhat worn cam?

 

Cheers

Luka

Edited by Bulatovic
Link to post
Share on other sites

Hi Luka,

before you remove the head try tightening the head nuts. It may be that the previous owner did not have them tight.

It is odd that the oil gallery at the rear lefthand side is leaking without the #4 bore blowing the gasket.

Look for cracks in the block around the oil hole.

 

The timing chain and tensioner can become very noisy if the tensioner breaks - and it can.

The chain and tensioner can be done in situ - remove rad etc.

 

With the head off the followers can be lifted out. If the cam looks perfect then replacing the followers could be done but may induce premature wear in the cam.

You can use a piece of tight fitting wood into the followers to lift out - keep them in the order they were removed.

 

Good luck

 

Roger

Link to post
Share on other sites

Roger, that i haven't thought of! Could have tried the bolts... One thing that's actually making me slightly nervous is that i have absolutely no idea what's going on with the engine or if it's ever been properly serviced (hopefully yes), and if it actually is a dodgy gasket, i'd rather replace it now before it mixes coolant with oil...

 

Guys what are your opinions on exhaust systems - Stock 4A iron manifold with standard dual box exhaust (with front box removed) by Double S, or going full on with Phoenix and it's much higher bore 4-1 extractors and twin exit exhaust? Would the latter provide any significant benefits on stock or mildly tuned engine or perhaps make it worse due to lowering exhaust gas speed because of the bore diameter?

 

Cheers

 

Luka

Link to post
Share on other sites

Standard Triumph made quite a reasonable job of the production 4A manifolds, both inlet and exhaust, and any benefit to be derived from a four-branch manifold on an otherwise relatively standard engine is modest indeed.

 

Dyno testing of years ago clearly demonstrated to me that the potential exhaust gains, manifold and system alike, were minimal - until such time as the engine cr had been raised and the head seriously worked over.

 

I have found rather more benefit to be achieved simply from delivering both manifolds to the head man, and leaving him to make the best of them, matching manifolds to head and mildly porting as required.

 

A much better investment than shelling out loadsamoney for a bunch of bananas to do no more than overheat the engine bay . . . . . . or which in too many cases simply reduce mid range torque for minimalist top end power increment. There are a considerable amount of crapulous exhaust manifold designs littering the history of TR tuning . . . . . .

 

As for exhaust systems, again it's easy to spend a lot of dosh for a very small return, or worse . . . . . . the standard system isn't bad, and over the past 20 or so years the various boggo stainless systems I've purchased from TRGB have proved to be more than satisfactory. We are of course talking of relatively standard or mildly tuned engines here, not roadrunners or trackburners !!

 

Cheers

 

Alec

Link to post
Share on other sites

Cheers Alec,

 

So, basically not much benefit unless full upgrade to the engine (89mm, sportier cam, etc...) - so i'll keep the manifold stock for now - a mediablast and a coat of a VHT flameproof paint, so that's sorted!

 

I'll give it a test with re-torqued head, perhaps it stops leaking, so i can gather full info on what i really want to do to the engine and finish it in one go - head, cam, bearings, balancing, manifolds, etc...

Link to post
Share on other sites

Update - head nuts undone one flat the re-torqued to 105 lb-ft, unfortunately with no result... it did leak a little less, but still it showed oil through the powder after 3-4 minutes of running at -2'C outside... again, with oil at 90'c or more it would definitely make a puddle... and the pushrod tubes are still silly.

So a head-off job for sure - and then i'll see the state of the bores. I also plan to take the sump off for a clean and a re-seal, so i guess a cam inspection can be done also.

Only then i'll be able to make a final decision on what to do with the engine - a rebuild with modifications or just sorting the head and fitting new gaskets everywhere...

 

Cheers

 

Luka

Link to post
Share on other sites

Do you guys reckon that it'd be easier to get the block breather plug out with the sump down, knocking it from the inside of the engine, rather than trying to pry it out with a set of tools from the outside? - as i'm considering ordering a snorkel for the block...

 

Cheers

Luka

Link to post
Share on other sites

Do you guys reckon that it'd be easier to get the block breather plug out with the sump down, knocking it from the inside of the engine, rather than trying to pry it out with a set of tools from the outside? - as i'm considering ordering a snorkel for the block...

 

Cheers

Luka

No as there isnt direct access from underneath.

Stuart.

Link to post
Share on other sites

A decision too early, how did the retorque go ?

 

After you released the tension by 1 flat from the head nuts and started the incremental torqueing at 50-80-105 lbs ft at what point did the nuts start to tighten ? early or not until the final retorque ? this gives an indication of at what torque the head has been running at.

Now you've decided that the engine is to be reworked anyway why not remove the head and start from the beginning ie find why you have this blasted oil leak !

Where is it coming from, is it just a crumpled or damaged gasket ? or something more ? about 90 min work will have the head on the floor and then you can start diagnosing, inspect the gasket, obviously look for the blow and the oil track through to the outside, check over the head and it's running gear and valves and all the other bits and bobs as they come off including the inlet manifold. DON'T try and lift the head from the block by using the compression or stuffing rope into the cylinders for the piston to lift it, the liners need to be left in their seated position and doing either of these practices may break the seal at the bottom figure of 8 which they seat upon. Sometimes the head is reluctant to move, judicious tapping with a copper mallet or a "deadshot" hammer around the outside and corner areas especially and in an upward direction will do the trick. It's a heavy lump anyway so a friendly lift from a mate along with yourself may need to do the job, climb into the engine bay if necessary and straddle the block to lift, or if you can get the engine and car under an hoist connect the head and gently apply upward pull as you tap the head, that normally works.

After this is done noted and photographed clean the top of block surface and liners after removing the gasket and measure the protrusion of the liners in 4 positions around each liner top to the block (depth micrometer or feeler gauges if you can get consistent results). Write the protrusion onto the block or liner so you don't forget them or mix them up.

 

At this point some of the cruder assemblers amongst us may say " well it's going to have a rebuild anyway just rip it to bits quickly" but the idea of a careful dissemble is to diagnose what's been happening to help avoid the subsequent reassembly just duplicating any fault there but with new parts !

 

Mick Richards

Edited by Motorsport Mickey
Link to post
Share on other sites

Hi Mick,

 

Well, one or two nuts were off for a 50 lbs ft re-torque after being undone by a flat, the others needed be torqued up to 80 and then to 105.

It did seem to leak less though after tightening, but as i said - it was -2' C outside, and even after 3 or 4 minutes of running, there was a leak.

 

When i first got the car - in May 2015, it wasn't even close to how it leaks now, so something degraded with usage.

It may be that the gasket was never replaced (and since the car was sitting in the US for veeeery long time - i'd say more than a decade from it's state - and as i was informed by the PO it was checked and given an oil change and it ran ok) that wouldn't come as a surprise. So perhaps a crack?

However, a few months ago when i've done a compression test it showed somewhat steady 150psi +- 10% across all cylinders, so i'm not sure that liner protrusion has changed or that it might be the cause of the leak - correct me if i'm wrong - but i'll definitely check the measurments when i get the head off and clean the block surface.

Can you recommend a technique for cleaning the block after the gasket is off?

Also, what steps should i take if it turns out that the liners are off compared to the block top? i guess a visit to a machine shop then - like this -

http://www.tr-register.co.uk/forums/index.php?/topic/54919-problems-with-89mm-liners-and-fo-8-gaskets/&do=findComment&comment=456804

which would mean pretty much a full rebuild?

 

Cheers!

 

Luka

 

Link to post
Share on other sites

Liner and block cleaning I normally use a cellulose thinner and a sharp blade. The thinners will dilute, soften and help remove any sealant used the last time the engine was built, and the sharp blade will skim the surface and lift it from both items.

Don't forget to secure the liners down when the head is off, use large washers over the tops of both liners where they Siamese together slipped over the studs and with a tube (I use old gudgeon pins) in between them and the head stud nuts, torqued down to about 40lbs ft (not critical).

 

As I said on the last post this strip down needs to be forensic, it may well be something stupid and easily sorted and if the liners and pistons are decent without a huge amount of wear and the liner heights are reasonable it may be a tough call not to decide to just rebuild the core and zip it back up (I'd drop the sump and pull a mains and big end bearing also just to check) but if you're lucky and problems don't abound you could be driving it again in a couple of weeks.

If however you decide that it's going to be given "the beans" whilst you've got the head off then I'd pull the engine and gearbox complete and start jumping all over it, headwork leaking tubes, cam new followers, timing chain and tensioner , new liners and pistons etc, any exhaust or ancillary bolting on can be done afterwards...Oh and pull that block sealing plug for a breather in the block wall.

 

Mick Richards

Edited by Motorsport Mickey
Link to post
Share on other sites

I'm sort of hoping for the scenario where i would just clean the head, measure everything, and put it back on again with mild head service - skimming, new guides and a clean

If any more work is needed, i think it'd be best to do the whole engine in one go (pistons, liners, chain, tensioner, cam, followers, head...) and forget about it for a long time :)

 

I was hoping to be able to knock the crankcase breather plug from the inside - but i guess it'll be a rather long fight with it... (where does it sit when looking from the inside of the block? is it in a sort of a pocket or - i thought it was just a hole, like the one for the petrol pump...)

 

Cheers

 

Luka

Link to post
Share on other sites

+1 ^ with Roger. Many engines in decent nick will run happily with a PCV valve and unless you're going into a much more aggressive engine with revs use the PCV will do the job.

 

Mick Richards

Link to post
Share on other sites

I removed mine in situ a few years ago ,

Drilled a small hole in middle with dremil, angle drill would be better but I didn't have one.

Then used shortened chisel about 50 mm long with end sharpened like a fish hook.

Bang through hole, turn 90deg and prize out.

Use short greased stick to remove any swarf and just in case then change engine oil.

Snorkel is an easy hand push fit with a bit of sealer around OD.

Chris

Link to post
Share on other sites

Hi guys, a little update:

- level of frustration: Infinite.

 

Everything was unbolted in about 20 minutes - rocker cover, rockers, inlet manifold, exhaust manifold, thermostat housing, head nuts...

But the stupid bl**dy head is still on!!!

 

The right hand side studs must be soooo rusty that i've managed to lift the entire car by the cylinder head with not a single thing bolted. That's the power of rust i guess...

Decided to keep it soaked in WD40, under slight separating tension and come again tomorrow with a bigger hammer.

Really, i'm out of ideas... The other part of the head - where the rocker tubes are has separated, but i have no idea what to do with the other side. Torch maybe - getting the studs glowing then cooling them down? Keeping them soaked for days in WD40, and giving them light taps on the side to move them just a tiny amount but enough for the rust to separate, or something different..?

 

any advice highly appreciated!

 

Cheers

 

Luka

Link to post
Share on other sites

WD40 isn't much good for that. Better to use a proper penetrating oil or diesel. Lots of discussion about that in old topics on here.

Link to post
Share on other sites

+1 for diesel.

 

If you can build some reservoirs with plasticine or other product a few mm high around each stud and then keep topping it up with diesel as the level drops that will normally work. Careful with bashing the head with large hammers, you don't want to crack or even chip a piece off. You're doing the right thing keeping a separating pressure on the head, patience and perseverance will pay off here.

You say the head on the passenger side has lifted ? If you double nut any of the studs on the passenger side can you extract any of them through the head ? any wiggle factor gained can help breaking the rust seal on the other side.

 

Mick Richards

Edited by Motorsport Mickey
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.