MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Exhaust manifold

I just pulled the exhaust manifold off the TF to replace the exhaust flange studs and have noticed that the manifold is actually burnt through in one spot (casting fault ? ) I can weld the hole with a high nickel rod .
As an alternative I have a really good manifold to replace it with but the port sizes seem fractionally smaller ( about 2mm ) . Is it OK to grind these out or is the manifold for an earlier car ? ( It has the MG logo cast into it). The outlet at the flange seems the right size.
Also, I noticed that one of the core plugs in the block is weeping so I suppose I should replace them all. Are there any tricks to this on the TF ?
Regards, Rick.
R Payne

Rick,

There's quite a bit of meat on those old Hotckiss-designed heads. I would't worry too much about a paltry 2mm on the exhaust ports.

While at it, you may want to cut back the inlets, at the same time, done quite easily with a flat file. In fact, you can cut them back so that the metal in the siamese ports (inlet) can be flowed to a knife edge as I suspect, many of us have done.

If you have (access to a copy of) Philip H. Smith's book 'Tuning and Maintenance of MGs', you can find a good pic of this facing page 113.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

Rick,
While you have it off you might want to check this out:
http://www.ttalk.info/picture_this.htm#JetHot%20coated%20manifold
IMHO ...best $100 I ever spent on my TF.
Lowered operating temp by about 20 degrees.
My manafold had been "repaired" by a PO (as you can see in the pictures)...have had no trouble since I did this and after 6 years it looks about the same!
My TF was very prone to vapor-lock prior to doing this. (check archives for the whole story)
Also don't know how true this is (as work was done by a "shop" not myself)...last summer I had my XPEG re-built and was told they purchased core plugs from well known supplier. I do know that the large brass one behind the exhaust lasted about 250 miles before it "popped" and melted down 2 new pistons. The shop told me they were too small and on next go-around they purchased plugs from NAPA! I have about 500/600 miles on the new ones. Sorry I don't have more details, but the shop that re-did my engine is no longer in business.
Check the archives for more info on plugs!
Cheers,
David 55 TF 1500 #7427
David Sheward

Gord, I was unclear in my posting, I meant the manifold ports were too small - ,maybe someone has already worked on the head, as the ports you mentioned have been filed.
David, I might put some araldite or silastic around the housings before I put new plugs in. Will see if there is Jet Hot in Australia.
Thanks, Richard.
R Payne

Rick,
Re weeping core plugs.
When rebuilding TF motors I use stainless steel plugs together with a strong steaming sealant.From my experience,plugs "pop" out because many owners/mechanics think that a British car must have imperial sizing including the core plugs!They should of course be the slightly larger diameter in metric.
Touch wood,I have'nt had a replaced weeping core plug in owning TF's over thirty years!
Hope this helps.
Cheers
Rob.
Rob Grantham

Richard,

The Ceramic coating process is amazing. One of our Rockburnians has an MGB with a small block Ford and heat was a major problem, The ceramic coating of his headers was an almost-instant fix.

He did not use Jet Hot which is considered by many as more of a cometic coating (aluminized, bright silver appearance), but nonetheless quite effective. Rather, he used the Swain process which involves a heaver, white coating.

Evidently this is a whole new field of emerging technology. For an interesting story try:- http://www.swaintech.com/store.asp?pid=10969

I don’t know of anybody in OZ doing this process, but I can’t believe that the Yanks are the only ones in the game.

Also, try Googling ‘Ceramic coating of exhaust manifold’.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

Now you tell me. I just got mine back from the Jet Hot people. :)

Don't be fooled by the "cosmetic" propaganda, though. Jet hot type ceramic coatings do work. Us British V8'ers swear by them to keep under hood temps down. Do they work as well as this new product? Maybe not, but they do make a big difference.
Carl Floyd

I forgot to add, in Jet Hot's case, the headers don't come out shiney. They tumble them to make them shiney, if you want. Plus, they did my TF exhaust inside & out.
Carl Floyd

Carl, what was the cost on the jethot coating? BTW, got hats and pins today.

Mark
Mwhitt

Well, I started grinding out the pit in the manifold and found a network of cracks - basically the manifold is cactus. Will use the other manifold which seems OK. The port sizes in the manifold seem to match the gasket, so maybe someone has had a go at the head and then opened up the old manifold to match.
I took the manifold to be grit blasted and am just going to coat it with hi temp manifold paint - we live out away from the city and there is not much hi tech out here.
Will use some loctite pipe thread sealant around the core plugs.
Regards, Richard.
R Payne

Carl,

I'm told that the best results come from coatimg both inside and outside, as you have done.

I know the hot rod boys here swear by Jet Hot hence my comment " ..but nonetheless quite effective". I only know the results that my friend got with the Swain process.

I have a spare cast iron manifold, but am undecided which process to use.

Gord Clark
Rockburn, Qué.
Gordon A. Clark

Rob, are the stainless plugs readily available? Richard.
R Payne

My understanding from the boyz at Jet-hot when I did my first one there (6/7 years ago) was the "big differance" between them and others back then was that they "DO the INSIDE" of the manifold. (Check their website to see if this is still the case).
I have had several others done since and noticed an increase in HP (slight...maybe 5hp?) and operating temp (-20?) in all of them. Cost was right around $100 and turn-around about a week. The shinny finish (sterling) is the cheapest..they can do it to look just like orginial (kind of a dull white) for a slightly higher price.
Cheers,
David 55 TF1500 #7427
David Sheward

Hi Rick,
With regard to TF stainless steel core plugs,the last lot I bought was about 4 years ago from a WA Motor firm that is not here now. However,a company like Coventrys,Repco,or a motor reconditioner should be able to come up with these plugs.While you are doing the plugs,check to see that the 2 small holes located in the blocks "swollen" casting (under the exhaust manifold and opposite the 2 core plugs) are in fact clear of hardened muck.This helps to keep motor temperatures down.
Enjoy your TF no matter what the maintenance frustrations are.These cars are magnificent!
Cheers for now.
Rob. G.
Rob Grantham

Rick--- I have replaced 2 core plugs one small bottom front and also the large one behind the exhaust manifold I obtained brass ones from Sportsparts in Sydney however they where a tadge on the small size when hammered home so I replaced them again this time using a sealant all is fine now.All the other plugs look fine so I have not bothered to replace them. Be sure to get all of the muck out of the block and reverse flush the system when doing the job. Finally I added 500 mls of "Penrite Long Life Inhbitor Plus" which has anti corrosion properties.As a matter of interest I had previously replaced the same two plugs some 12 months prior those where made from pressed steel which I had obtained from Moss and fitted in the UK before shiping the car out here to Oz.
Good Luck
Richard MG 52 TD
Richard Hyde

David Sheward, what did you specify to get the "dull white" finish from Jet Hot? I sent my manifold this morning and they will call me to talk about finishes. Initially, I was told the sterling finish is sort of a shiney "Chromy Look".
Jim Merz

Dave posted a url above: http://www.ttalk.info/picture_this.htm#JetHot%20coated%20manifold
It shows the finish....
gordon lawson - TD 27667

Gordon,

The Swain coating sounds good & will look more original than the Sterling finish I did.

Mark,

Total bill from Jet Hot with return S&H was $122 plus what it cost me to ship it to them.
Carl Floyd

Anyone had a manifold done to know a price on the Swain process?
gordon lawson

Gord Lawson,

Give Swain a call. They're not far from you - Rochester - [585] 889-2786.

Gord Clark
Rockburn, Qué
Gordon A. Clark

Thanks for that, I have just about got all of the core plugs out - drilled a hole in each plug and then made up a little tool to hook them out. Some of them came out very easily - just as well the cooling system does not run much pressure! Quite a lot of garbage in there.Will look around for some stainless plugs.
Regards, Richard.
R Payne

Both the intake and exhaust manifolds of my MGB, MGC, and midget are Jet-Hot coated. Underhood temperatures are much lower as a result, and fuel economy improved in all cases. You can bet that the TF will get the same treatment.
Steve S.

I've yet to try my new Jet-Hot coating, as I'm still assembling my car. However, for a few dollars extra I choose a dull gray coating, much nicer on a TD than the shiny one. It is a darker gray than the original very light gray, but it looks good to me.

warmly,
dave
Dave Braun

Dave Braun, would you be able to provide a picture of the gray finish on your manifold? Mine is still on the way to Jet Hot and the color is yet to be decided. I agree that the chrome color finish seems a bit bright.
Jim Merz

Jim,

When you talk to JetHot ask them about leaving the outside unpolished. I've had quite a few things done there and I've noticed that some of the smaller items like bolts aren't polished to the sheen that the larger item are. When they're left like that they look a lot like the original aluminized manifolds do. They've also mentioned a "sparkle" finish that sounds interesting also - it's not polished like the normal JetHot coating is. I work about 5 miles from the factory and have been there a number of times.

Gene

Gene Gillam

Hi Gene, I'm confused about the location of Jet-Hot. I sent my anifold to Tempe, AZ. Mabye they have several branches. Thanks for the tip about leaving the exterior unpolished. I'll ask when they call.
Jim Merz

I found that there is a Jet Hot in Melbourne Aust ,so have got the manifold back from the grit blaster ( he had not done the job) and am sending it to Jet Hot.
When the bottom core plugs came out the entire gallery to the top of the plugs was choked with garbage, so it was worth removing them. Will refit with stainless plugs.
Thanks for your advice, regards, Richard.
R Payne

Jim,

I understand your confusion...I'm talking about their Pascagoula, MS., location.

Gene
Gene Gillam

Thanks Gene, I didnt know they had more than one facility. Perhaps I could have sent my manifold there faster and cheaper.
Jim Merz

They have several facilities. I sent my manifold to Pascagoula. Their headquarters is located in King of Prussia, PA. That is where you send the money.
Carl Floyd

Hi again Rick,
Re core plugs and cleaning block.
Now that you have the plugs all out,just to more clearly reiterate-look into,via the 2 small core plug holes, the rectangular gallery on the right hand side of the engine block.
With late XPAG AND XPEG motors,(ie round hole blocks),directly behind the 2 core plugs,you should see 2, 3/16ths inch size holes connecting the
rectangular water gallery on the side of the block to the cylinder water jackets.MAKE SURE THESE 2 HOLES ARE CLEAR.Use a small scew driver or 1/8th drill as I had to do to eventually break through the accumulated often hardened muck. Initially,there may be no evidence of these holes but continual pressure will eventually allow a break-through.(a little like the Tassie miners rescue!!)
"Banana holed blocks" usually have 1 drilled passage behind the rear core plug.
I have known owners to rebuild a motor completely,often for overheating problems at high speed,to find that they were unaware of these 2 holes and still overheating after the rebuild!
Cheers
Rob.
Rob Grantham

Thanks Rob, I found these two holes and ran a 5mm drill through them. You are right, they were rusted up and covered with gunge!
Regards, Richard.
R Payne

Hi Rick,
Good stuff finding and then clearing the holes.This forum is an excellent place to extend knowledge of both TD's and TF'S.MG people the world over are a well nit bunch and only too happy to assist.The forum often also stops you having to do every job on your car twice!!
Cheers
Rob.
Rob Grantham

I read an article some years ago, I dont remember where, that said we can improve the cooling of our XPAGs by cleaning out the casting residue behind the forward and aft core plugs. I used a straight punch and hammmer to loosen them One by one and put a mechanics magnetic tool in the hole after knocking each particle loose. That way, I was reasonably assured that I had removed the loose pieces. You can see/feel these pieces that obstruct the coolant flow. I am about to put this engine into service so I will soon learn if there are any benefits.
Jim Merz

This thread was discussed between 24/05/2006 and 31/05/2006

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.