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MG MGB GT V8 Factory Originals Technical - Manifold Dilemma.

Hi,my block hugger manifolds have just about come to the end of their useful life [warped and cracked], i have had enough of struggling to get them off and more importantly trying to get the bl***y bolt holes to line up to get them back on again without blowing, [the manifolds not me], also on average one starter motor every two years.

Anyway i have trolled through the archives to see what might be the best long term ooption, it seems to me that nobody reccomends the block huggers exept for asthetic reasons [the reason i like them].

Now to my question [at last i hear you cry]. I am going to the classic car show at the N. E. C. this saturday and i am feeling a bit flush and i have 90% made my mind up to buy a set of rv8 manifolds [although i do not like the idea of cutting what seems to me huge holes in the inner wings],i am sure when i was at the show last year i saw some for sale on the Bhive stall which i thought were quite reasonable, but after going through the archives i noticed that one or two had problems with these fitting properly,i also read that clive has them for sale and that they are top notch quality but probably twice the price [i am not that flush]i know 'you get what you pay for'.

has anybody bought some of the Bhive ones recently?, did they fit ok? can you fit them without lifting the engine? quality ok?

Or has anybody any for sale that might be going to the show? I hope i havn't rambled on too much but any thoughts would be very welcome.

Thanks Graham.
gt young

Go for Clive's - this is what he does and if there are problems - he will see you right.
Roger

I have stuck with block huggers (stainless from Clive) and have no problems with R & R.

I am not after the ultimate power output and also have no real overheating problems despite the heat here.

I fixed the starter motor problem with a gear reduction job. This give an extra 1 1/2 inches of clearance from the exhaust pipes.

I can have the starter off in 10 minutes and either side manifold off in 20 minutes.

FWIW

cheers
Ian Buckley

Clives are well made and come in six sections which push together neatly to for quite a complex shape.
For each bank, The manifold off the heads, a right angled bit, another section and finally a join together bit (a siamese I think he calls it) which locates under the passenger seat at the standard "muffler join" location, ie you should be able to use your existing muffler.
This all adds up to lots of flexibility when fitting, which is the reason I got it/them.
My memory is cloudly on this , but I think they were around 400 pounds. There is also an muffler system availiable which was impractical to ship to Australia. If you have the later brakes then you may need to unbolt the master to get the RHS in, certainly to cut the holes, (unless you're double joined with prehensile toes). I occures to me now that it may be easier for you to cut these from the wheel side, not the engine side. Clive also sells the RV8 metal reinforcing hole surrounds, which would make locating/cutting the holes much easier I imagine. He seemed a decent sort of guy on the phone.
Peter

I have also had problems with warping of block huggers. I did replace them as they were cracking regularly too, but the new ones have also warped. I welded struts in between each flange to hopefully hold them in the right positions, haven't had them off since to see if it works. Not that they are currently without problems, within hours of refitting them after a top-end rebuild I had blown a couple of the gaskets. These were the single composition-metal-composition type and had blown the composition out. I reverted to double metal-composition-metal type as they are stronger but one is still leaking a bit. But the real problem is that the passages in the manifold are significantly bigger than those in the head. This does allow a certain amount of flexibility in lining up the passages without blocking the head ports, but it does mean that the overlaps on the gaskets can be very narrow and this is the problem with mine. The next time I have them off it will be to fill in part of the manifold ports to give a bigger overlap. Heat wrap on tubular (not cast iron) manifolds should help the starter, and I have also seen starters wrapped with heat insulation sheets. I use none, I did have to change the starter a couple of years ago but that was after 60k and 7 years or so in my ownership so I wasn't too bothered. I can alo get the (standard) starter off and on very rapidly and without removing anything else excpet the heat shield (you do have one I suppose?) but to remove the right-hand manifold I have to get the rack out. The reduction starter is so quiet the first time I used it I thought it was only spinning and not turning the engine, but it doesn't have the coil boost contact so might make the difference between starting and not starting under advers conditions. Can be simulated with a relay though.
Paul Hunt

Graham,

I'm just about to go this route. I understand the BH system just needs some fettling but in view of problems with Manifolds decided to go with similar to CW for easy fit and will use High temp Silicone for gasket and coat outside with Black Satin rather than go for coating by Camcoat.

Paul
Paul

Thankyou all for your input, i think that if Roger and Paul both prefer Clives manifolds then i would be a fool to ignore their advice.

Ian, i do not realy want to stay with the block huggers given the problems with fitting and removal, a gear reduction starter will be high on my shopping list if i have any more problems with the one i have now.

Peter, i am not at the moment after any more than the actual manifolds as i have a twin exhaust system, i just hope that i can make it fit the rv8 manifolds, but thanks for input.

Paul, i have to admit that i have never had a heat sheild fitted, the starter is that close to the manifold that i cannot see how i could fit one in the available space without risking it shorting out the starter, maybee they were a poor set of manifolds in the first place, i have seen you mention the high temp silicone in previous threads, i have tried to find this in places like Halfords etc. but with no success any pointers would be appreciated.
I agree with you on the size of the ports in the flanges on the manifold, way too big IMO not much clamping surface for the gasket, i only hope that the rv8 ones are better.

Thankyou again for all your inputs.

Graham.
gt young

Graham,

I've got MGBHive manifolds on mine, I was one of the people who had difficulty getting them to fit, they had not been jigged correctly, but BHive sorted them and they are now excellent, and they were much the cheapest ones on the market at the time.

You can come and check them out and take measurements if you wish, I've got a pit in my garage. You can't be far away.

I also have a full set of 'spectacle' exhaust gaskets which I bought to replace the single gaskets I have on , but as they are no longer leaking, I probably won't need them in the near future, so I could let you have these at whatever they cost me from MGOC.

Mike
Michael barnfather

I don't want to start false rumours but I was under the impression that all silicon was high temp., even that which seals your bath. Even if special high temp. silicon is sold (and I haven't seen any) it would not surprise me if it was a scam. Does anybody know any different?
ian thomson

Ian,

A selection
http://www.mgchemicals.com/products/silicones/hightemp.html#

I understand designed re Space Shuttle but is now available even in my local Auto shop.

Paul
Paul

gt young - Clive sells a heatshield that although shiny is almost certainly constructed of a non-conducting material. I used to have a metal one which *did* short out to the solenoid stud once, now I have Clive's. It is possible to remove and replace these by just slackening the securing bolt (battery ground-strap disconnected!), I would think complete removal then trying to get the bolt back in *with* the heat shield over a standard starter is nigh-on impossible.
Paul Hunt

Michael,

Thankyou for your positive note on the Bhive manifolds, i priced Clives manifolds up today £360.00 + vat + about £75.00 + vat for the re-enforcing rings.

So what i have decided to do is have a good look at the Bhive ones at the N E C, I have took all the measurements, bolt centres etc. You never know i might find a used pair for sale {we all live in hope}.

As for the manifold gaskets, i am affraid that i have bought a gasket set off Ebay £5.00 + p+p {not bad eh?}. But thanks for the offer, I will look you up, probably in the new year, i am only 30 miles away.

Paul,

If i decide to go the RV8 rout i should not need the heat sheild, but it is nice to know that if i need one they are available i was just worried about it shorting but seems that clives got the answer with his sheild.

Thanks for the link for the silicon site, very interesting at least i know now what to look out for. Do you use it with or without gaskets? Thanks again, Graham.
gt young

No Gasket required.

The most common prob with Manifolds appears to be right rear (real pain) and left front therefore looks like a prob with jig, although always used standard thin gaskets with no probs on 3.5. the 4.6 was a diff story so changed to RTV.

Never used a heat shield and even the 4.6 with block huggers has never caused a prob. The RV8 system should add a few bhp and allow better cooling in engine bay.

Paul
Paul

............provided you remember to lag 'em before you fit 'em.

Mike
Michael barnfather

Mike i will be very wary of lagging my manifolds in the future, the one that i did lag [off side] split in three different places, [hence my thread] though they are mild steel, that may have a lot to do with it, maybe stainless steel would'nt have split.
Thanks Graham.
gt young

There is s stunning set of manifolds made by a company in South Australia. They are affiliated with RPI and you can buy through them or direct. They appeared in a car in the magazine MG world March last year
I didn't get them because at the time I thought stainless wouldn't discolour (I particularly like the look of stainless) There is a photo somewhere in the archives.
Peter

Graham......that's surprising. I had a set of lagged m/s block huggers for about 12000 miles that were OK when I swapped them, these SS ones have done maybe 15000 miles so far with no problems.

I know the cast manifolds had problems, but that was because they touched the engine block, and people didn't file back the engine number casting to clear.

Lagging does considerably reduce underbonnet temperature, I've used 1" fibreglass tape (available from plumbers merchants) painted with black heatproof paint.....I'm told TVR use the same plumbers merchants for their lagging !!.That's good enough for me.

Mike
Michael barnfather

This thread was discussed between 05/11/2003 and 11/11/2003

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