Advice Needed Please.

[Tesstuff 222]

Before my head gasket went i could easily get to 105mph in 3rd and it revved quickly too,then one of the symptoms that something was wrong was that i suddenly couldnt get to 100mph in 3rd and it took its time getting there,one of my thoughts when i was booking my car in for its head gasket and skim was that i would get that performance back again, i have been 'running in' the engine since the head gasket job but the performance hasnt returned and now it struggles to get to 100mph and it takes its time doing it.Last night on a private farm road i once more tried and it got to around 95mph and i just felt like i was being mechanically cruel and backed off,it just doesnt rev so cleanly as before,i have to hang onto a gear and get to the speed rather than it getting there quickly and me needing to change gear.

 

What might be the reason ?

 

Might the car need 'setting up'?

[j_turnell 137 3 Cars]

Yeh sounds like the fueling needs adjusting and check the ignition timing. No need to run it in after doing a HG.

[steve@cornwall 100]

My money's on the cam timing being put 1 tooth out on reassembly.

To check, I'd mark the dizzy position then rotate dizzy fully clockwise, If it's been put back together right it should pink quite heavily under load - if it's out it won't pink

Edited June 17, 2008 by steve@cornwall

[simonb 0]

If the head has been given a skim then the std cam timing holes will no longer be correct and the cam will now be retarded depending on how much was taken off. The only way to correct this problem would be with an adjustable pulley.

[Tesstuff 222]

OK i think i need some proper help on this one.

 

I have rang the mechanic about this, who is Carl of C.G Cars(Mechanical Repairs) on the 306 Gti-6 forums and he is definite the cam timing etc will be fine as he had to put a pin? in somewhere to make sure all stayed good while the head was done.

 

He has asked me to bring it back for a look on Thursday morning.

 

Can you let me know what i should be asking him to check?

 

He replaced the dizzy cap as well but not the rotor arm would that make a difference?

 

I hate this , its being in the dark time and it just feels terrible

[gti-si 0]

I don't think a skim (dependant on how much of one) should make any difference to the cam timing. I doubt the timing will be a tooth out, heard he does alot of cambelts and is pretty reputable.

 

I would however, say the ignition timing could be retarded. Are you running different octane fuel? Ask him to make sure the ignition timing is bob on. Or have ago yourself, there's plenty of how-to's on here. Changing the cap won't make any difference.

 

Might be worth checking your ignition components? Might not of been the headgasket casuing the symptoms? Just a conincidence?

[Tesstuff 222]

Funny you should say that, V- Power was so cheap at the garage the other day i put a full tank of it in.

 

I did this to check out the mpg difference to be honest.

 

So yes i have V-Power in my tank at the moment and my top speed is down about 10mph!!

 

So am i to think that this fuel octane can make it struggle to rev to the redline and also knock that much off my top speed?

 

I will ask Carl to check anything ignition related.

 

Thankyou for the suggestions

[welshpug 1,657]

no, that fuel should do the opposite, especially if the ignition is setup on it.

[Gentrix 2 1 Cars]

no, that fuel should do the opposite, especially if the ignition is setup on it.

 

In theory fuel with less octane should burn stronger and more easily. To prevent selfingnition you raise the octane level but it becomes less responsive. So in a low comp. engine (you have a DFZ?) it´s contra produktive.

 

But if you had the problem before the HG - then my money is on the cat going tight. I had this with every single car now.

 

 

andi

[Tesstuff 222]

When i bought the car in May 2007, it had a 75mph top speed.After various mechanics looked at it, the final one diagnosed a collapsed and knackered cat and we replaced it.I then had a top speed around 110mph.It also did 105mph in 3rd gear.

 

It drove well until the steam started coming out the back and at the same time i noticed it struggled to reach the redline and top speed had also dropped.I thought this would all be cured with the head gasket job.

 

So i had the head gasket done, head was skimmed and i have been running it in for 500 miles.But i decided to see if all the performance had returned and it appears it hasnt.The car barely reaches 100mph and it cant get past 95mph in 3rd.

 

So something is making it not rev so freely and taking a good 10mph off my top speed.

 

It has a 10 month old cat, might this be a good excuse to decat it like the MOT chap said i should?

[simonb 0]

I don't think a skim (dependant on how much of one) should make any difference to the cam timing.

 

I disagree - if you shave some material off the face of the head the valves are moved closer towards the pistons meaning that the cam timing is retarded form its normal position if the standard timing holes are used. Obviously this depends on exactly how much is skimmed but if you have a head which has been done a couple of times in its life then this will become more of a problem. This will also have a direct effect on the ignition timing as the dizzy is driven by the camshaft and I doubt very much that the fueling would have been altered as a direct result of a head gasket replacement.

 

I would spend some time looking into this as logically the only things that could have changed are valve and ignition timing whilst the head was off. I also suppose that incorrect valve clearances could cause performance issues so it may be worth considering this also.

[Tesstuff 222]

Ok i went to the mechanic today and here is what happened.

 

He said it had a 'cleaning skim' when he had it for the head gasket replacement.The whole head came back chemically clean.

 

As it is a Gentry and an auto, he wasnt able to see how to check the timing, he went to do it like he would with a manual 205 Gti and apparently there werent any notches on top of the gearbox.So he couldnt check my timing.

 

I made a suggestion about the dizzy being turned like someone in this thread said and he said he would turn it but i would maybe end up needing a new dizzy.

 

He turned it forward and the tickover got smoother and slightly faster and he suggested i took it up the road to see if it had improved matters.

 

I had a 7 mile run and that change did make it rev slightly cleaner to the redline and it seems better.

 

But he advised i would at some point need a new dizzy now.

 

So i still have no idea if my timing is correct and i need a new dizzy lol, gotta love these cars

[welshpug 1,657]

having the head skimmed "shouldn't" affect the timing, as you should fit a thicker gasket to suit.

 

unsure why you would need a new distributor, but if you do get in touch with H&H ignition solutions, they can rebuild them and adjust them to suit any modifications at very reasonable cost.

[Tom Fenton 1,542]

All this "new dizzy" stuff sounds like rubbish to me. By the sounds of it, it just needs the ignition timing setting up properly by someone that knows what they are doing.

[mattmk1 0]

All this "new dizzy" stuff sounds like rubbish to me. By the sounds of it, it just needs the ignition timing setting up properly by someone that knows what they are doing.

 

Unless the vac advance has gone for a crap.

[simonb 0]

Agreed that diagnosis sounds pap to me too. you dont need marks on the flywheel to set the timing. My money is still on the cam timing and ignition timing being off the mark. Sounds like you just need to give it a go yourself and try the obvious first. How about a spare (with working vac advance) dizzy from another motor to rule that out first?

[steve@cornwall 100]

Agreed that diagnosis sounds pap to me too. you dont need marks on the flywheel to set the timing. My money is still on the cam timing and ignition timing being off the mark. Sounds like you just need to give it a go yourself and try the obvious first. How about a spare (with working vac advance) dizzy from another motor to rule that out first?

 

Has the vac advance pipe been refitted - they are fiddly ....... "new dizzy" seems to be suggested by too many garages, I think because they are so expensive (they'll quote you new pug list price) it's pretty certain you won't have it done.

 

I all honesty, if the guy can't set the ig. timing without timing marks

[lagonda 42]

Must say I've never heard the phrase "cleaning skim" before. A head skim is shaving some metal from your cylinder head, to ensure that it is perfectly flat, so that your new head gasket doesn't blow, and a chemical clean is to clear old oil & corrosion from the head. As others are suggesting, it sounds a bit like he's trying to blarney you.

[Tesstuff 222]

And yet he is the top man on the 306 Gti6 forums, they all go to him and treat him like a 'god'!!

 

It just doesnt make sense.

[Alastairh 47]

All this "new dizzy" stuff sounds like rubbish to me. By the sounds of it, it just needs the ignition timing setting up properly by someone that knows what they are doing.

 

I agree.

 

He may well be the top guy on the 306 forum, but he might not be use to the older stuff like 8v 205s.

 

Al

[M_R_205 5 1 Cars]

Must say I've never heard the phrase "cleaning skim" before.

Apparently they do it when fitting a new gasket to save them cleaning all the old gasket of the mating surface, its just a fannys hair of a skim just to make the surface shiney, and ensure a good seal, probabaly less than a 1/4mm, but even so will affect cam timing slightly,

 

Sounds to me like you need to find a better mechanic, stick a new rotor arm in to go witht he cap and get it timmed up properly, also might be worth some new plugs if the HG went and water/steam was getting in

 

Paul

[Baz 421]

And yet he is the top man on the 306 Gti6 forums, they all go to him and treat him like a 'god'!!

 

It just doesnt make sense.

 

Ahh, now i think i know who you mean...

 

Most skims are only a few thou, so a 'cleaning skim' unless it needs more for a reason of course!!

[Tesstuff 222]

Would anyone check my car over for me? I am prepared to travel.

 

Just want to know the timing and rotor arm and plugs are all good.

 

After spending all the money on the head gasket it would be stupid to not make sure all the other bits are performing as they should.

 

Let me know cheers.

[simonb 0]

I think you just need to meet with someone nearby and compare their car with yours (providing that theirs is on form). Just having that initial comparisan will confirm in your mind if there is an obvious problem or not. Remember that 1.9's are generally very temprimental and it doesn't take much to throw them off.

 

TBH, I would just experiment yourself unless you feel that this is not an option and just try the basics like advancing the cam / ignition timing to see if you notice a difference. Until you have checked these items and know for sure that they are out then you could spend forever trying to get to the bottom of it. I would have a look for you myself but I'm right down in Hampshire and so it's not really an option. I am more than willing to offer as much advice as I can though....