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MG Midget and Sprite Technical - Burned through intake valve on cyl #2

Not sure why or how but its just as teh title says. The head is going to come off soon and I'll take tons of pictures. The head will then get sent to apex engineering in bensenville for a rebuilt. I plan on doing more than that though. I figure this may be a great chance to get teh head upgraded somewhat with larger valves, bronze valve guides, hardened seats, larger than stock stellite valves, a port and polish job etc. I am not sure exactly what is optimal so if you guys have suggestions I'm all ears.
S.A. Jones

That's a tough run of luck...1st. the rear end job (But that's why they call it marriage) then the car wreck, now a busted head.

What caused the intake valve to burn up???

what are you driving while its down???

Id take the head to a good local machine shop and have it striped, cleaned, & Magnafluxed before you do anything, Id buy all the parts your self and have the shop assemble them...that will save a chunk of change also.


have you looked into minimania/7 enterprise/etc. and see what a stage 2 head would cost ready to bolt and go. that might be an option

BTW..make sure you buy payen gasket set, its really high quality and wont have to worry about any defects

and don't forget to rebuild your rocker assembly with all new fresh bushings.

Prop
Prop

Yeah I've had a series of disappointments. by now I don't care. its a learning opportunity each time. The cosmetic stuff is more dishreartening than anything else. mechanical stuff is the stuff I can repair reletively easily. body damage looks awful and I am not equipped to repair it right. Still, im learning that no matter what happens there is always a chance at making it live again (barring the complete total destruction of the car leaving little more than a few bits and pieces)

Stage 2 head from 7 will run into the thousands. However, an unported big valve unleaded smog head would be 500-600 bucks. The problem with 7 is that they don't machine everything, they import the stage 2 stuff from England so there is a lot of shipping costs to recoup. Commonly they are more expensive than an aluminum head. I think the same is true of Minimania but I could be wrong. Apex engineering is close to where I am and they come with good reccomendations. I called them and they quoted me at 350-500 depending on how much is done. I just wondered what the best valve sizes are etc. That is a great point about the bushes on the rocker arms. hadn't thought of that. Any pointers?
S.A. Jones

I dont think you can go wrong with the mini cooper valve size...its a bigger balanced valve size and yet it wont crack heads like a bigger valve combination


intake 1.4, exhaust 1.15

Another thought on the rockers, go to APT and get the offset bushings, that way you can get some extra lift ratio...I think there just a few dollars more then the standard bushings, the benifit is like adding a hotter cam.

In this economy, Id certianly call the supplier like 7 and mini mania, and others as well. Ask about a better deal "Just because your "The Seth Man"" no doulbt they will play ball to make a sale


Prop
Prop

Sounds like you were either running the front carb too lean or had the gap too small on that valve (or both). What do the other valves look like?

There are some benefits to the aluminum head, but some report that the actual flow is not that great.
David "light-headed" Lieb
David Lieb

Prop, What was the stock size for midgets?

David, I'll have the head off soon, and take plenty of pictures.
S.A. Jones

I took the head off and this is what I found!


S.A. Jones

More of the damage


S.A. Jones

Last but not least!


S.A. Jones

Doesn't look too bad in the photos, Seth. Is there really a valve problem or just the usual HGF between 2 and 3?
David "use Payen next time" Lieb
David Lieb

Payen? I used fel-pro whats the payen part number and where do I get it?
S.A. Jones

ps, not so sure about the valve problem anymore
S.A. Jones

Part # CF473P

British parts northwest


http://www.bpnorthwest.com/.sc/ms/dd/Sprite%5E2FMidget/9779/HeadSetPayen1275


Prop
Prop

Doesnt look any different than my gasket set. On the box it says that the head asket itself was made in england
S.A. Jones

"Out of stock"...
:-(

but Payen IS the way to go

Payens for Metro Turbos have been recommended here at times too
Bill sdgpm

Seth, Sorry to hear about your engine trouble. Was your car the subject of the front suspension rebuild at Barney's house this weekend ? Will the tech session be cancelled ?

Tim
TMc

The metro turbo head gasket is excellent, never had one go.
Brad (Sprite IV 1380)

The tech session is still on. It will get there no matter what it takes!
S.A. Jones

I see that you have not yet learned rule number one of club tech sessions... NEVER let them operate on YOUR car. Tech sessions are fine for observing (especially for learning what NOT to do), but I would not want my car to be the victim.
David "you should have seen the MGB windshield installation the NEXT day..." Lieb
David Lieb

The Right way, The Wrong way, The Better way....hand me that piece of bailing wire and the ball pen Hammer

Prop
Prop

BTW...Have you put a straight edge across the face of your cly. head...it may be suffering from some minor warpage at the #2/3 cly. area...Id do that to the deck of the block as well

esp. if your "blowing thur" Hg at a fast rate

Prop
Prop

"esp. if your "blowing thur" Hg at a fast rate"

Hg as in mercury? The clyninder head is in the capible hands of the machine shop now. Having larger intake valves put in along with hardened seats etc.
S.A. Jones

Hg as in HGF, Head Gasket Failure.
David Lieb

thanks david,

I didnt know how to spell Head Gasket so I just used the "abv." LOL.


Prop
Prop

ALright, so with some help it was roadworthy in time for the tech session. Then 90 miles later the head gasket blew again. We thought we made sure the block was flat with a sharpening stone but I guess it wasnt. The new gasket didnt look that great to me when I put it in. I guess they make them in saudi arabia with bad quality controls these days. I'll try payen next.
S.A. Jones

>>>>>>>We thought we made sure the block was flat with a sharpening stone<<<<<<<<<<


Well, Its NO longer a rebuild, thats for sure.

Seriously, You are money and HUGE RISK ahead just getting another 1275 engine. Put in a new cam, lifters, oil pump, all gaskets, bearing shells and pistons w/rings and a good hone on the cly. and ARP hardware... call it a day. and you will have a good engine for years to come.

rebuilding the current engine is doable but WOW, the risk is super high, like in OFF the Charrt scale. you could always take the current engine apart and (really clean it good) and keep as spares or "god forbid" sell on ebay....How you will ever get all that "Wet sanding stone" grit out of the engine is beyound me, its got to be everywhere by now, in the oil gallerys, the water passages the crankshaft, camshaft crevisios all the bearing, I cant even imagine, its got to be like oil, a little bit goes a really long way, esp. at 4500rpms

NOW, Im SOOOOoooo glad I thoughly wash all my used parts I buy from ebay.

Im so sorry to hear this seth, I truly feel for yeah, I guess you can take solice that you didnt use a dry stone, I doublt you would have gotten 50 miles before a Ba-boom

Prop

If I can help let me know, I may have a lead on a couple 1275s locally

Prop
Prop

Well Prop, the stone idea was at barney's insistance and FWIW he's done this on engines that have gone on to last another 100,000 miles. There really isnt any grit or anything anywhere on any bearings, besides now the block is being hot tanked and pressure washed etc.
S.A. Jones

Seth,
Look at it this way... IF the stone did any good for levelling the block, grit and metal were displaced. Where did they go? Just because you can't see it does not mean it isn't there. Could be a very expensive mistake. I sincerely DOUBT that any engine that had this done to it went "on to last another 100,000 miles" without a rebuild or two along the way. LBC engines don't tend to do 100,000 between rebuilds very often and a stone is not usually a part of a REAL rebuild. OTOH, since it didn't help your situation at all anyway, the engine did not last long enough to injure itself any more. Might be a lucky thing...
David "better to be lucky than good" Lieb
David Lieb

>>>>>>>besides now the block is being hot tanked and pressure washed etc.<<<<<<<<<<<<<

It seems extremely high risk to me, id ask the shop to allow you to be there and take part in the cleaning process, Id spend hours upon hours with a case of pipe cleaners and tooth brushes with heavy focas in the oil and water ways followed by just massive amounts of high pressure washing in the those galley ways, I still think you are 12 future rebuilds ahead just getting another engine, how your going to get ALL that super fine stuff out, I just dont know, just remember any of that stuff left behind after a shop 1 hour of clean up of soak and pressure wash is going straight into the all your engine bearings and between your head gasket.

perhaps there is a filtation company like fram or K&N that has a super fine filter that can filter something that super fine from the engine. you will need something for both oil and water


Id seriously talk to old gray norm about a block and head, at the vary least. you can get something really good at a great price...if not ask the shop if you can spend a saterday doing all the cleaning of the block and head and plan on a long day of extreme small detail cleaning.

Prop
Prop

Prop I did the same blesed thing with the knife stone about 5 years ago and 5 years later all the bearings look fresh, the bores are smooth, and there isnt anything wrong with it as far as excessive wear. teh fact is that more grit results from honing cylinders and reboring everything than results from running a knife sharpening stone over the top of the block to clean things up, and yet engines somehow survive being honed and bored out. Just make sure you wipe everything down and wash out stuff with laquer thinner. The rest is taken care of by oil filters and the magnetic drian plug. If you are really worried about this ask the expert at www.mgaguru.com
S.A. Jones

This thread was discussed between 25/04/2009 and 08/05/2009

MG Midget and Sprite Technical index

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