cabbykarl

ok so I fit my head to the engine, timed it up nicely as it's easy, started it up n cyl#1 wasn't firing at all.

Did compression test n zero comp on that cylinder leading to me suspecting a stuck open valve.

Took head off and found that both the #1 inlet and exhaust valves were bent

So, this made sense as the head is off a fiesta rst which had chucked a rod through the block. Yup I did notice when I cleaned the head that a valve was open but assumed it was just the cam position it was taken off in.

Now my old engine was also a 1.6cvh but an old carb jobbie. I inspected the valves and measured them and found them to be the same diameter as the rst head.

One spring compressor fun time later and i'd put them in.
Head back on, inlet, exhaust, plumbing and wiring reconnected. Topped up with water and fired her up again......

Started up fine 1st time so i let it idle without touching the accelerator till it had warmed up a bit.

Weeeeeellll revved it up to about 2k really gently and it starts making a nasty clattering sound. Sticking my ear to a block off wood on the rocker cover tells me it's coming from cyl#1....

The question is have I made a bit of a mistake by fitting an inlet valve that isn't quite the same as the rst one?

It's the same diameter and obviously length etc but isn't as dished out as the turbo one.

Here's the pic of my old cvh head:


As you can see this pic of the rst's inlet valve shows how dished they are:


Now is it this machined away for the purpose of piston clearance or just compression or something??

I'm a bit lost and yeah I know I should have waited to buy another proper one but is was saturday and Ford quoted me £29 for 1 so I thought i'd chuck this one in and give it a whirl.....

Please help if you can as i've put this engine together twice now and ain't gonna test those head bolts a third time

DROPTOP

yeeehaaaaa

you sure all your rods are the same length and out of the same engine ? lol

seriously though , i dont know .

Tom Phillips

check your inbox just sent an answer to it by mistake i ment to post it

SafeChav

Without being rude that head looks in a right state!

Did you not have it skimmed before fitting it, shitloads of corrosion on there

The valve shape shouldnt make any odds, but did you lap it in with grinding paste, for one ........

SafeChav

And have you fitted new headgaskets both times? Thats a small fortune down the drain!

cabbykarl

Nope, i re-used the gasket. That's the old head lol. The one i put on is all nice n clean. in fact i think it had had a nice chemical wash not so long ago as there isn't even any oil discolouration.

Didn't lap the valve in as both it and the old one were in pristine nick. even the old carb head one was not pitted at all much to my surprise.

And nope I didn't rotate any of the engine without the belt all timed up properly. I took it off and put it on as per the Haynes manual's instructions ie set the engine to tdc 1st.

Soooo at a bit of a loss.

Turned the cam around a bit with the head off then put it back to it's marker at the top too. All valves and lifters seemed to be doing their job fine when i did that.

Wouldn't it be evident all the time instead of just when i rev it?

it's definitley something hitting something as it's just too rattly for anything else.

cabbykarl

off to watch jay n silent bob...

back after that

DROPTOP

the springs all ok ?

SafeChav

re-used gasket.

nice

Didn't lap the valves in.........

With all due respect mate, i'd find someone that knows what they are doing to finish the job for you.........................

cabbykarl

Ok fair enough opinion,

So you're telling me that Ford have produced an identical capacity 1.6 cvh engine but have cut different valve seat angles in? Like I said the mating faces were unmarked and when i popped the valves in it fit perfectly. I used the same spring and collet and retainer as was fit before.

As for the headgasket why not use it again if, which i didn't tell you i know, it had been on for 14 days but ran for only prob 100 secs? ie it came straight off and was still like new.

Any more ideas?

IANS2RST

iTrader: (1)

all the valves are slightly different due to manufacturing tolerances & should be lapped in to produce a perfect seal.
as for reusing a head gasket it gets compressed when u torque it down & will not seal proerly a secondtime.
think you should get help from someone who knows what they are doing
u may possibly get away with your bodges on a non turbo car but definately not with a turbo charged engine

cabbykarl

Reaches into pocket.....

SafeChav

You always should lap valves in when you change them, you can't guarntee the seat in the head has worn in the same way as the valve you are about to fit, and for what time it takes i would always do it, just for peace of mind.

As for the head/head gasket, HOW MESSY is that head to start with its covered in corrosion, the mating face isnt even clean. I also bet the bolt holes are full of oil and crud, which then means when its torqued you will get hydrauliuc lock and its not actually torqued down accurately. When doing things on engines generally everything needs to be as clean as possible!

You may well of got away with re-using the gasket if it hasnt got hot, i personally though wouldn't recommend it all, its just not worth it.

I did wonder whether you would take offence to what i said but i felt i needed to say it simply because you are going to end up costing yourself more money.

If you were close by i'd happily pass through and give you a hand.

Just as an example when i took the head off my car, i spent a fair time cleaning the block face and the bolt holes etc, before refitting the head which was also skimmed, and to be honest i wanted to get it cleaner than that but it was getting dark

cabbykarl

Ta for the replies peeps.

Safechav you keep thinking that pic is the head i have on now when it says above it it's the OLD one lol. That's my old carb head which i pulled off my old engine whilst the whole lots been removed from the car as it's now got a efi turbo lump in.

I took considerable time to clean the block mating face. It was totally clean as a result ie no gasket material left and all thread holes cleaned out meticulously without leaving a trace of debris, oil or liquid of any kind in there! Last thing I wanted was to like you say try and compress water etc when tightening up the headbolts and possibly cracking the block!

Likewise the head had been chemically cleaned but ran for an unknown but <1000 miles on a fiesta rst running normal boost.

Again I took the head home and much to my wife's displeasure sat it on the living room table and proceded to spend approximatley 3 hours cleaning it with wrags, soapy water and a toothbrush!

I'm going to take the head back off tomorrow and get some pics up for you guys to ponder over.

Yep don't worry i'll buy another headgasket & bolts this time just to be safe!

I'll take the head home and take the valves out, labelling everything as I go so it's put back in exactly the same order. hmm a compartmentalised box will do.

Thanks very much for the offer of a hand!
Unfortunatley unless you fancy a holiday by the sea here in Scarborough I doubt you'd hop in ya car and drive up for the hell of it pmsl!

Bit of a bind all this as it's looking like i'll have to sort it by myself

If the worst comes to the worst and this heads shot then anyone got another? EFI type obviously....

PS Moi take offence??? Never.....hehe. Constructive criticisism I can just about handle

cabbykarl

An idea of how clean my EFI head is:


Turbo block going in.....this is before i cleaned it too:

SafeChav

I must of missed where you said it was the old one, so sorry

Above all, the head should make the engine make noises, UNLESS its been skimmed too much and the pistons are touching the combustion chambers, but there will be marks evident if this is the case!

I could do with getting away, how much are you offering lol

Standard Ford gasket or Payen is what you want

cabbykarl

Yeah i know about the overskimmed situation but don't think that's the prob. Taking the head off will tell me for sure though.

How much am I offering? Sheesh and I thought we all did this for the love of RS not for financial gain!!!!

J/k hell if you're ever up this way i'd stretch to at least a beer or two

SafeChav

Chavs dont come cheap, or at least i dont anyway

cabbykarl

I'm not worthy, i'm not worthy

lol

cabbykarl

Hmm another thing... I might be able to get hold of an EFI 90 spec xr3i head.

I know they're identical but are the cams the same as the turbo ones?

SafeChav

Heads/cams/valves all the same

But ive never pulled a cam out of a CVH that i'd want to re-use....they are always fucked.

cabbykarl

Yeah i agree but i'd just clean the head up and inspect the valves then try it as a whole and not bother swapping any bits to 'make a good 1'

I'll phone 'em up and have a laugh at how much they want...

cabbykarl

1st response.... 'we'll only sell you the complete engine sorry'
2nd response.... ' we just had a clearout of old escort engines, we chucked 'em all away'

sheeesh!

SafeChav

What did you ring up for

cabbykarl

Just a replacement efi head.

DROPTOP

loads of xr2i's in the scrap yards

cabbykarl

Took the head off today and didnt see anything obviously wrong.

I've searched this forum and found a topic about how high the pistons should project out of the block and mine dont seem to be any different than maybe up to 2mm over the block face. The valves, spings and rockers all seem fine. When i take the rockers off, the guides dont seem to have any play in them so i dont imagine the valves wobbling.

The head gasket was mounted correctly so it couldnt be that either.

How hard are the followers supposed to be? i.e i can push a couple of them down maybe a millimetre but the others are solid. Is this because they are only compressible until they fill with oil?

I roughly measured the height of this EFI head against my old carb head and it seems to be about 1 millimeter or so shorter in height. Surely this isnt too much material taken off?

Can anyone tell me what the uncompressed height of a normal spring is?

When i first ran the engine (before knowing it had 2 bent valves in the head) it obviously sounded like a lawn mower but i switched it off after 2mins messing max. Now taking the head off today i can see that the bent inlet valve had been hitting the piston causing a very slight i.e about 2 millimetres across mark. Could this have damaged either the small or big end bearing? I only ask as all i can think of is that the piston is able when revved to rise much higher out of the bore and actually is hitting the combustion chamber.

I think my next plan is to mock re build the engine but not tighten it up fully and use some plastercine on the crowns, put the belt on, use 19 mm on the pulleywheel for afew turns and see if there are any imprints.

SafeChav

Unlikely the valve hitting has damaged the big/little ends!

A mm is a lot for a head to be skimmed by, you need to find the original heaght of the head casting.

You sure the cam your using isnt fucked? The lifters will compress as they are sprung loaded, oil pressure makes them solid.

cabbykarl

Hmm I agree about the bearings, was just throwing ideas about.

Is there an easy way to see if cams over worn? ie can I just take a lifter out and feel the lobe or do I have to remove the cam as a whole?

Ordered a new inlet valve today so I won't be trying to lap the old one in to what appears to be a nice unworn new seat. The other three inlet valves are like brand new without even any deposits on the stem or under side.

Going back to where I briefly mentioned the springs....another theory maybe; the head has been unused for about two years. Is it possible that with both the inlet and exhaust valves on cyl#1 been stuck open about <5mm for that length of time the springs have compressed to a smaller size permanently. ie they've been weakened and are now not returning the valves to their normal closed position. This would account for normal operation at tickover when the spring doesn't have to work so fast, then when revved it can't keep up creating a gap between the lifter and the cam lobe too large for oil to gap so it's audible as a rattle when the slacks taken up again on the next lift phase?

I've never read or been told the effects of weak springs but i'd expect that sort of behavour??

Here's to clutching at straws!

SafeChav

Well for a start 99.9% of the time if the cam is worn significantly the lifters wont want to pull ouot of their bores, and forcing them out will wreck the head!

Any dishing on the lifters face also indicates significant cam wear, hard to see wear on the cam without removing it.

I doubt the sprigs have gone weak, everytime you stop the engine there will always be a valve open.

cabbykarl

The lifters pop out of the bores nice and easy, just pull with your fingers.
Im just lapping all the valves in as we speak. Lifters are totally flat at the bottom, no dishing at all.

How bad an idea is it to use 2 springs out of my old head?

SafeChav

Sounds like the cam is in a good state then if they are all perfectly flat and shiny.

Springs off your other head should be ok, can't see any problem with that.

cabbykarl

Thanks, will put them in and dummy build the engine back up tomorrow and wind it over as i said previously. New gasket and bolts arriving on friday.
Still lapping the valves in and cleaning the head at the moment, ill post pics up when im done.

SafeChav

Lapping valves in shouldnt take long.

And you don't need to lap the ones already in there in

No harm in doing them though i suppose

gup

iTrader: (1)

when you put the cam in did you check to see if the woodruff key is in and the pulley is located on it correctly
as it sounds like its not thus beliving you have it on t.d.c ( when fitting the timing belt) when the cam could be anywere (spelling)
also are you timing it up correctly

iansoutham

Throw the cylinder head in the bin.

I had exactly the same problem with an XR3i MFi cylinder head once. Kept bending valves every time it was revved. Turned out to be a dodgy guide, even though they looked fine and lapped in okay.

Changed the cylinder head for another one, was fine ever since. Still got the engine infact, even though the shell died from metal moth.

SafeChav

A dodgy guide bent your valves

iansoutham

No, not quite, A valve moves in a guide, if the guide is slightly out of shape / cracked / bent, the valve can catch on an imperfection in the guide when revved which can cause it to momentarily slow, allowing the piston to catch it up with the inevitable result.

It is not that common with CVH engines, but I have had it happen personally, and know of @ least one other with the same problem.

There is the same problem with Ford 8v TwinCam engines. If a valve gets bent, it almost always disturbs a guide, which will mean that any replacement valves seem to end up suffering damage further down the line.

If you think about the symptoms being described, it does make sense.

A new valve is fitted in a used cylinder head. When started, it is fine. As soon as it is revved, the valve bends. The only way a valve can bend is if it is smacked by something to alter its angle of travel, in this case, a piston. The only way a piston can hit a valve when revving is if the valve is suddenly moving slower than the piston, hence the getting caught up on a guide.

SafeChav

Ah ok.......i see what you mean, that must be a VERY uncommon occurence though

cabbykarl

Is it easy to pull a guide out of my old engine then or are they pressed in at manufacture?

Just something that if it's reasonably easy to do then i'd do it just in case.

Hmm but still a guide that was bent enough to 'slow' a valve moving through it would be quite apparent wouldn't it? They seem ok to me upon inspection so i'm going to change a couple of springs anyway as those, if they're weak, would surely cause the same effect at speed.

Like I said though i'll build it up tomorrow with old bolts etc, time it up and manually turn the pulley wheel, take the head back off and see if there are any imprints in the stuff i'll stick on the crowns. Yup i know this'll only emulate slow rotation but it'll eliminate what someone else mentioned before about the cam possibly being wrongly positioned on it's pulley.

Nighty night peeps, catch you tomorrow!