69 replies to this topic

[wolfie]

decompression plates are a bodge its that simple, if compression needs lowering then use dished pistons and/or chamber the head, if you dont have the money to do forced induction properly you are better off not doing it at all as you will end up spending out on bodges

personally i would not buy from a company that a) uses its customers as a test bed like this b) supplies a bodged up decompression plate as part of a kit

See, this is kinda why I prefer only the people involved in the situation to reply!

Don't Vmax scart (who've been supplying kits for years), also use decompression plates?

having being doing forced induction now for some time i do have a little knowlege on the subject, its my personal opinion that decompression plates are a bodge, there only supplied as it makes it easier to sell a kit as people dont have to strip there engines, anyone whos had any forced induction experience will tell you that the head gasket is always your weak link decomppression plates mean double the possibility of failure

if you only posted about a sitution you are involved in there would be no posts on this forum, theres alot of people out there with alot of experience but clearly you know best jammy so ill let you carry on

[neil_g]

please can only KER781G and jonspeed post on this from now on.

Jake can you ask Jonspeed for a reply on this?

All other posts will be deleted.

everyones entitled to an opinion.

personally mine is that this is another example of an idea being ripped off and reproduced without the R&D that was done by the original creator. for example the copied KAD quickshifts, they dont always fit correctly.

i think theres been more than enough bad press on this subject for people to make up their minds about using particular companys.

i think thats worded quite diplomatically.. if not..

THIS IS MY OPINION AND DOES NOT REFLECT THE VIEWS OF THE MINI FORUM (before anyone throws their toys )

[Gr4h4m]

If both gaskets have gone, i can only assume the head torquing procedure has not been adheared to, many of the Vmax Scart boys run the decompression plate with out issue, though that kit is a different ball game and i cringe at the thought of mentioning Vmax Scart in comparison, there is none!

Dont forget that two head gaskets means that the gaskets will relax twice as much reducing the clamping force of the joint considerably, and most of us know, if the gasket is going to blow, its likely to be between the cylinders. I doubt hyour mating surfaces are to blame, or the decompression plate, its more a matter of procedure.

You are right though, the overall package is not well thought out. Just my opinion and is mine my own.

Sprocket I would love to know more about the procedure. or are you referring to the Haynes style or something more advanced

[Custom_Minis]

Having read into the other thread last week about Supercharger kits - I have been thinking:........

If people do go the route of a decompression plate and the head gasket is the weakest link in forced induction engines, are people spending upwards of a £1000 on a conversion and then using £7 gaskets????

If so, surely it would be beneficial to use 2 group A gaskets (or similar/better spec) - all be it a lot more expensive but more up to the job??


I may be completely wrong and might get shot down but I'll learn a little more about this conversion along the way.

Les.

Oh, and these my own words/views and not those of Custom Minis Ltd.

Edited by Custom_Minis_Ltd, 14 November 2007 - 06:17 PM.

[minisprint]

awaiting the reply from jonspeed!

[Bungle]

it should be on its way

[Sprocket]

If both gaskets have gone, i can only assume the head torquing procedure has not been adheared to, many of the Vmax Scart boys run the decompression plate with out issue, though that kit is a different ball game and i cringe at the thought of mentioning Vmax Scart in comparison, there is none!

Dont forget that two head gaskets means that the gaskets will relax twice as much reducing the clamping force of the joint considerably, and most of us know, if the gasket is going to blow, its likely to be between the cylinders. I doubt hyour mating surfaces are to blame, or the decompression plate, its more a matter of procedure.

You are right though, the overall package is not well thought out. Just my opinion and is mine my own.

Sprocket I would love to know more about the procedure. or are you referring to the Haynes style or something more advanced

If it were me, i would run the engine without coolant to get it to running temp, then i would let it cool fully, then retorque the head studs, fill with coolant, run it up to running temp, then again let it cool and re check the torque, dont forget to back off the nuts before retorquing. I wouldnt run the engine under load untill this was complete.

Now where does it say that in the haynes manual? Its a similar procedure but its not the same

[Gr4h4m]

Thanks Sprocket I have tried similar before. I'm I correct in thinking this is best with the fiber style gaskets and not the copper ones or does it work with both?

[Sprocket]

I would do it on either

The copper ones are fibre as well, they are not really 'copper' gaskets.

Unless you have an anealed copper gasket, and that is a totaly different ball game altogether

[Jake Blues]

Apologies for the length, it's a bit of a saga...well a sequel really....communication, communication, communication...


The customer was told the Jonspeed car was nearly always available for test drive but it does need to go out with other customers and to the rolling road and on other duties. A phone call prior to leaving would have sorted this problem. I could not ring the customer has I had only spoke to him at a show.

The customer emailed me to tell me he had a problem with a supercharger kit he had purchased from me. I said no problem I would get the car collected and I intended to do this the very next day. When the customer called he did not speak to me but was told we were having problems with our trailer and would be over asap. When I say I will call in the morning I meant between 8 am and 12 not 8 am - 830 am and sometimes I get held up which I cannot help. He was also asked if could bring the car to the workshop instead and we would get onto it straight away. He called us and told one of my staff he would be there around 6.30 pm which was 1 hour after we closed but I thought well I will just wait. He then called back and told another member of staff that he would not arrive until about half past. That member of staff assumed he meant 6.30 and maybe the fault was with us that he actually meant 7.30 pm not 6.30 pm because if he had said 7.30 pm he would have been given him my home phone number so he could call me as I live 3 minutes from the garage. I do have a life outside of work and I also have young children that I want to see so I can not be open all the time. I also have lots of emails to answer to customers and member of the public wanting general help with their car.
I saw that the induction pipe had been battered to death with an hammer. I asked why and my customer’s mechanic said it does not fit with the servo. I said it’s a servo fitted to a car that did not have one as standard and they are slightly more over to the right. The customer’s mechanic then came at me very aggressively and said I was talking rubbish only not so politely. I said that the servo could be a much a 1 inch in either direction by time it gets to the point where the induction pipe was fitted and if he loosened the servo he could push it over to the left wing allowing clearance for the kit. This I personally showed the customer on collection. (I have seen this too..Jake)
I tried to calm his mechanic down because I did not want a confrontation but he was very aggressive and in the end he went outside. I then stayed behind until 10 pm to look at the problem he was having. When the servo was moved the pipe fitted no problem but looked a right mess so I decide to fit a new one which took 24 hours to make and get e-coated. I went home and the next day started sorting the other problem out which was the pulley touching the bracket not allowing it to turn. I looked at this problem and found the bracket just fouling the pulley. I relieved this by about 5-10 mm.
The problem with the bottom bracket is it was pressed out and comes in various shapes which are not always the same. I have now modified the instructions to make our customers aware this can be an issue. I have fitted many of these kits and was not aware of the problem until this kit. That is why I offered completely free of charge to fit the rest of kit as my way of an apology to the customer.
I had fitted the rest of the kit to the car when I realised that the rockers were seized solid and no amount of freeing oil was going to make them adjust. I tried for around 30 minutes to get two of them free and in the end the slot at the top of the adjuster broke. I replaced them with another set free of charge. The rockers are unfortunately bolted down with the head studs so if you let the head studs free it means the head needs to come off because it would not be professional to have just retorqued the head only at the back. I removed the head and noticed both faces had been cleaned with flatting paper. I assumed that due to the cleaning and the fact the customer was using a mechanic and he had fitted the head both faces had been checked. I popped two new head gaskets on and the decompression plate. I refitted and retorqued the head, refitted the exhaust and super charger. I then ran the car to make sure it was running ok and that there were no air pockets in the water system. I set the ignition timing and got the car to run ok up and down the drive but it still needed time to be set it up correctly before it was driven hard and the customer was informed of this on collection.
The customer had also told me that the car was going to the rolling road to be set up.
I was informed the car had broken down on the way home so I said we would come and collect the car and if it was down to us we would put it right free of charge. If it was not then there would be a charge. The only time that the car could be collected was 6.30 am in the morning. The workshop does not open until 8 am but to keep the customer happy I asked one of my staff if he would get up at 5 am and he could go home early to make up for it.

Now I have the car back and start looking at the problem straight away. I tried to turn it over and notice the starter motor had been burnt out. I fitted a new one so I could start the car. I soon realised it was down on compression between 1 and 2 and 3 and 4. I removed the head from the car and checked the faces and realised the head was not flat. It was down between 1 and 2 chamber and also down between 3 and 4 chambers. I then stripped and took the cylinder head to be checked and faced at our local engineering shop. The calibrated the head and faced it for me. Why this was going on and we were waiting for the conclusion so we could call the customer and tell him the problem. The customer called us before we had the results back from the engineers. We said we could not take responsibility for the head being warped as his mechanic should have checked this. We said the whole job to put right would cost £285 inc vat.

The customer then became irritated and asked me to put all the bits in the car and he would come and collect it has he did not want us to carry out this work. End of conversation.

The bits were then put back in the car. The head was then collected and put back together and put back in the car and the paperwork passed over to the person who does the bills as usual. They then informed the customer of the price.

I then had a phone call from the customers mechanic who said what’s going on. I then told him what the problem was which i had been told by an independent engineering shop that the head was down between the chambers as much as 8 thou. The mechanic then became abusive and said that he was coming to collect the car with some mates and I could not stop him and he was not paying the bill. I said bring as many mates as you like the car still is not going anywhere until the bill is paid. Down went the phone.

The customer then calls me and says he will collect the car on Saturday and pay the bill. I said look forward to seeing you.
The customer has been helped as much as possible in our opinion and where problems have arisen we have done our best to correct these and put them right but I cannot take responsibility for your mechanic that has never got it wrong. When the customer came to the workshop he was shown a copy of the independent report on the cylinder head which showed the head was down between the chambers by as much as 0.008". The mechanic assumed that the cylinder head was straight because it was running before and because he flatted it with sand paper and checked it with a steel ruler. This maybe ok for a standard 998 but when you are putting a super charger on this is not good enough. I did tell the customer the head was not warped but that it had been flatted down incorrectly causing the problem. Warped and not being flat a very similar things but caused by two different things. When we said warped that was our impression from experience but we had not received the report to say what the problem was exactly.
The super charger gasket went due to head gasket being blown
The stainless steel decompression plates have an excellent record and we have had no other problems with them other than this that I am aware of. We have run them on 1380s without problems and I personally have one on a 998. I was also very sceptical with them at first when we looked at lowering the compression but we use high grade stainless and are told by our engineers that the quality of the stainless material is very high quality. Payen now produce a similar one for the K series.

Thanks Carl @ Jonspeed

[pogie]

I might be out of turn here, so Jammy please feel free to delete this post if you feel it’s out of order.

I have been following this thread with interest, as a supercharger conversion is one of the options I have been looking at for when I rebuild my engine. I had a chat with one of the Jonspeed guys at Southern Mini Days and he came across as really genuine and enthusiastic and there seemed to have been a fair bit of thought put into keeping the conversion affordable. Some of the welding on the manifold was a bit poor and the bend in the inlet pipe could have been better, but these were just cosmetic issues.

I can’t help feeling that the problems here have been caused by Jonspeed marketing the kit as simply bolt on and away you go, and the poor working practices of ker781q and his mechanic. Why on earth did they feel that beating the carp out of the carb-charger pipe would help the install I don’t know, any sensible person would have stopped and sought advice.

I feel that Jonspeed are making a rod for their own back by leading people to believe that they can bolt a supercharger onto any old engine without causing any problems. You may be lucky and your engine may be in fantastic condition, but on the other hand it could be and old nail in need of complete overhaul. We haven’t been told the mileage or the state of tune of ker781q’s engine, but the head could have been leaking across the bores for ages and it may have been days away from head gasket failure for all he or Jonspeed knew. Fitting a charger to an engine with a head in this state will always have led to gasket failure.

Just my 2p worth, but if I was to bolt a charger to an engine without giving it a rebuild, I would always have a huge nagging doubt in the back of my mind hoping that it was not going to go pop at any second.

[Bungle]

i said something similar in the staff room

it sound as if its not a problem with the kit its self but maybe the fitting instructions need looking at a bring points like above to the installers mind

jake are you going to give feed back to the jonspeed guys ?

[Jake Blues]

Some of the welding on the manifold was a bit poor and the bend in the inlet pipe could have been better, but these were just cosmetic issues.

That was the original prototype and long since superceded.

On your post, I think you have a very valid point but the kit isn't really marketed as just a bolt on, you are always told that you do need to have a degree of mechanical knowledge. That is also pretty clear from the article in MiniMag a few months ago and also the other very similar Vmaxscart kit that is featured in last month's MiniWorld. I think though that your point about the state of the engine is extremely valid and perhaps one which hasn't been taken on board by one or two (from the 70 odd) customers who have bought the kit from Jonspeed at least. It is worth stating that if you want a really professional job with all the pre and post checks done then you really need to have these kits fitted professionally by the supplier in my opinion. I am a time-served, apprenticed and qualified mechanic with 25 years of experience from motorbikes to tanks (in the REME) but I wouldn't undertake this conversion myself.

jake are you going to give feed back to the Jonspeed guys ?

Carl will be reading this himself!

[minisprint]

Hi carl thanks for the reply as i said at the end of the last post on this subject thanks for doing what you could with the mini and for suppling the correct parts which were missing from the kit.and for meeting us out of work hours. As for being aggressive towards you sorry if i came accross that way!never been told this before?. I said i had never came across this with the servo on my minis! and said I would find it hard to believe as it would make the pedals out also! As for hammering the intake pipe near the servo the customer asked me to do this and in my opinion the customer is always right! Also you admitted that we should have had instructions on modding the lower engine mount which the instructions we had had no reference and you said jonspeed had changed them to include this info..as for the phone conversation think it got a bit out of hand and the threat from you. came from a miss understanding that all i was doing was picking the car up from you on saterday and i had no bearing in which david was going to do regarding payment etc.after that spoke to sean skurvydog? and agreed to remove the post i had made!and agreed to just leave it at that!
I also agree that the h/gasket has gone causing the charger gasket to fail! But for the head gasket to fail in 5 miles?Did you do a road test?if this mini was in my work i would have been sacked for sending a car out that only managed five miles after a h gasket! you told david that the car was going to be tested.It is a known way to test head surfaces using a straight edge and feeler blades! as for never getting it wrong we anit perfect! i would admit to making mistakes where needed!I think as some people have said it appears to people that you can bolt one of these kits to any mini and make it go well when the truth is it is far from that simple.In mine and looks like so many others opinion the decompression plate is a quick fix to a problem not a cure!

The spacer that is used on the k series rover engine is bonded to the block using some thing like well seal. Ive used these too and they work!But they only use one h/gasket!and whey are used also to lower the compression back down to reasonable levels when skimming the heads after over heating usually down to the plastic dowels!

I think it is best to agree to disagree on this so no ones going to fall out with any one! and we can get on with what we like minis! Proberly see you at a show soon regards chris (the mechanic) p.s will leave any further posts to david (ker781g).sorry to the mod and admin!

Edited by minisprint, 15 November 2007 - 07:51 PM.

[neil_g]

IN MY OPINION the only reliable way to lower the compression is to build the engine with the relevent pistons and/or headwork.