MG MGB and MGB GT Tech Talk
What air filter are you guys using when you convert from the single ZS to dual HIF's? I bought two from VB and they are only 1" thick, but the rear one doesn't have enough clearance. I like the K&N filters but I really don't want to pay $66 for one and it may not fit either! Any suggestions would be greatly appreciated! BTW, I don't suppose that "massaging" the servo assembly is an option?
Thanks,
Frank
Frank, there are many options, but you might want to look at the top of this page for what some of the folks here have been talking about, http://www.cibolas7.net/17963.html .
Thanks, guys. Bob, I'm not real sure that one on your site will fit either - if I can find it. Also, I'd have to find a base. Chris, I used a K&N on my ZS and also on a Chevy truck I had and I do like them. I'm just not crazy about paying $120 for air filters and that's what they would cost from Moss. If I have to I will, but I was hoping for a less dear solution for the short term and then I may go with K&N later.
Frank
I use a set of chrome pancakes that came with a car I bought, they are a fraction over an inch thick and do have enough clearance;
Mine are the chrome pancakes from VB, that are almost exactly 1" and on the rear one the servo is inside the filter, so I can't put the cover on. You have HS4's on yours and I have HIF's. That may make a difference.
Thanks,
Frank
On the "other" board - UK MG Enthusiasts, I have recently posted my observations on these things. "Filtering oil, air, and Morons" and "new K&N filters". The summary is that the flat ones shown and the S&H repros are useless, kill performance, will kill your engine too as they don't filter worth squat. The K&N are acceptable, after you make spacers to allow them to be installed correctly. Why don't they come that way? Ask K&N!
FRM
Frank I have K&N on the 79 and jhave problems with the servo. I'll take a picture Tuesday when I am home and post here.
The K&N conical filters seem to be the only reasonble choice for a later car with the factory brake booster. There can still be a clearance issue if the motor mounts are not in good shape (especially the driver side).
They do need a bit of modification to the screw head on the back side of the mounting plate. It needs to be ground down a bit (and then Loctited back in) to fit between the mounting plate and the piston chamber. This is the case on both HIF and HS4. They come with a thick cork mounting gasket, but it is not enough to compensate. I will attach a photo of the back, and do note that this screw needs to be ground down to about 2/3 of it's original height (that still leaves a bit of a phillips slot).
Also, I have been buying these in quantity, and am about to place another order. I can give it about 3-4 days to add anyones wishes to my order. I can supply them at $52 ea. plus shipping.
My motor mounts could very well be the problem. I have a picture here of a late model B with those same filters on it and there doesn't seem to be a clearance problem in the picture. Anybody know off - hand what the thickness of the motor mount (the rubber part) should be?
Thanks,
Frank
There are commonly 1 to 3 spacer plates under the rubber mount, an adjustment by the factory to compensate for variation on chassis mount alignments. Adding a couple can help, but the problem is certainly in the brackets - the mounts don't squish that much even if broken.
Following I posted on other board a while ago:
"I have not found anything on the square spacers (shown in the Moss catalog between the rubber mount (item 91) and the washer and nut. My question is simple - does the square space go on top of the mount that is welded to the chassis(i.e., under the plate of the rubber mount, or inside the chassis mount? "
You will note that the square washer has an offset hole. The mount stud goes all the way at the bottom of the slot on the frame (tap it down with some weight on the mount), and the square washer offset is to keep it there so it can't move upward under any (loose) condition. Put the square piece in (yes, under the bracket - sorry)so that the widest part is uppermost, it just fits up against the top edge of the cavity. then figure out how to get the lockwasher and nut on!! Run a die over the threads before starting this so the nut is absolutely free-running - the threads are usually bunged up. Use anti-seize on the stud. It helps a bit if you can get the underside of the frame bracket clean (Brakleen or lacquer thinner) and use something sticky to hold the square washer up while you deal with the nut and lockwasher.
A further tip: Have you replaced the brackets on the engine? They commonly are broken, and if not near new are cracked and bent if not broken. Look very carefully at the 90deg bend at the front edge, and around the lower bolthole to the block. You DO NOT want to do this again soon! To greatly increase lifetime, Put 1/8" of spacers between the block and the lower bracket, and a heavy washer under the lower bolt head. You will have to grind this to fit securely in the channel at that point, and you need a slightly longer bolt. Be sure that the longer bolt will tighten against the stack of spacers and bracket without the lockwasher, then fit the lockwasher. If this bolt is bottomed in the hole the bracket WILL break, and the threads WILL be damaged when you remove it. This procedure prestresses the mount bracket and the rubber mount in a favorable direction and increases the life indefinitely. I've never replaced one I did like this, but have replaced dozens done as original.
When all is correct, the top and bottom plates of the mount will be parallel, and the rubber will be straight-cylindrical, not angled.
FRM
Thanks, Fletcher. I'll take a look at the bracket tomorrow. If I remember right, the rubber is slightly angled on mine. I worked for GM for twenty years in parts and service, and while I have seen rubber mounts compress with age, they do more commonly separate from the mounting plate. I didn't know if B's did the same, or if the rubber used in LBC mounts was easier to compress.
Thanks,
Frank
I was looking through some photos I took at a British Car Show. I took photos of engine bays that had two carb conversions so I could see how other people routed their hoses and lines. There is a picture of an MGB that has hif's and the exact pancake air filters that I have. It still has the original master cylinder and booster assembly. There looks to be about 2" of clearance between the rear hif and the booster. Those pictures are the reason I bought these air filters. My car has less than 1" clearance and nothing I have done will give enough clearance to get the top on that rear filter. I have jacked up the engine from both sides. I have tried using a pry bar to roll the engine slightly to the right so I can put the cover on. What can I do to get that clearance? With the engine sitting where it is now, I don't believe those high dollar K&N's will fit either - and I'm not going to spend $120+ to find out. Are there any other ideas? I'm fresh out. Oh yeah, the engine mounting brackets appear to be intact.
Thanks,
Frank
Frank-
If you look at the clearance, you will see that it is least at the bottom back corner. Some filters, including the tapered K&N, are offset up, or up and forward. So a one inch filter might or might not fit, depending on offset.
But a one inch filter is not worth a damn - see my thread "VERY IMPORTANT...", so take Jimmy up on his offer. I do not like the thick gasket that K&N supply - it cannot be tightened securely without distorting the back plate, it still doesn't leave clearance between the screw and vacuum chamber - which may irretrievably damage the carb; and when the gasket fails as it will, where are you gonna get another one? I made 1/4 phenolic spacers to fit between carb & filter, and used two OE gaskets.
If you have too little clearance to fit the K&N's, then your engine mounts ARE screwed up. Take a well lit close-up of the mounts from the side, directly parallel to the mount steel plats, and post it for me to see.
FRM
Thanks, Fletcher. I'll try to get you a good picture when I get home today. The car I took a picture of at the car show seems to have at least two inches of clearance at the rear hif. Mine doesn't have half that much. If I put on a new mount on the left side, won't that raise the engine and give even less clearance? On the older Buick Regals, the maintenance procedure for changing the back spark plugs (transverse engine), was to disconnect the upper torque strut and roll the engine forward for clearance. That was possible even with brand new motor mounts. My MG doesn't have anywhere near that much play in the mounts. I tried to roll it to the right enough to put the cover on the filter and it wouldn't move more than about 1/2 inch. That makes me think the mounts are good.
Frank
Frank, What year is your car?I've been told the 75 model year had a different booster that was larger in diameter. I had a 77 that the PO converted and used the thinner spacers intended for use with the induction heaters in cold climates and everything cleared well.I don't think those spacers are available any longer, but you could have yours machined.
John
Mine is a '75, John. That would definitely make a difference. I hadn't thought of machining the spacers. I knew there had to be a simple answer. If you look at the photo of the car I saw at the show, the spacers look like the full size ones.
I took 3/16" off of the spacers and it's still no go. I can't take off any more without changing out the intake studs. I really don't want to go back to the ZS and I don't want to order $130 worth of air filters and then find out that they won't fit either. The weather's been beautiful and my LBC is on jackstands. I'm really getting frustrated with this. I appreciate all the suggestions, but I'm still carless. Any more ideas?
Thanks,
Frank
MAybe you should consider taking pics or a 60 sec Youtube video so we can clearly see what you are up against...
Good Luck
Frank, those filters looker thicker than 1" to me. I just went and took these photos for you, there is 1 3/4" clearance between the carb and the brake booster, even with my 1 1/4" filters I can only just get the cover on the rear one, if yours are thicker it will be impossible. If that is the case the only thing I can suggest is to modify them to make them thinner, cut the mesh, foam and studs down.
OK, so it should fit. Now, my engine mount has a shim under it that lifts that side of the engine slightly. The shim is shaped the same as the metal plate attached to the rubber engine mount and twice as thick. That will raise the engine slight that side. The next thing you need to do is crawl under the car and look at your tranny mounts, maybe they have collapsed and the back of the engine is sitting low and to one side?
Which side is the engine mount shim on? If it's on the drivers side, won't it lessen the clearance? Wouldn't it have to be on the passenger side to tilt the engine slightly higher on that side? I'm really hoping my reasoning is right, because to remove the mount on the left (driver) side, you have to remove the steering shaft that runs through the mount! I'm fairly certain the tranny mounts need to be replaced because the underside in pretty well oil soaked. This car has been marking it's territory for a while. I'm tracking down leaks one at a time.
Frank
Offset conical K&N filters is what I supply to all my customers whe've made the conversion - never known of anybody having a problem with them.....but, there are copycat filters out there - make sure you get original K&N.
The shim is on the drivers side, but it goes on top of the rubber part, you would just have to undo that from the engine and insert the shim. However, have a look at your tranny mounts first.
If you put it on the driver's side, won't that raise the driver's side of the engine? The clearance problem is at the bottom of the rear air filter and raising the driver's side will bring it even closer, won't it? Am I looking at this backwards? Also, can I jack up the rear of the tranny to check that?
Thanks for your patience,
Frank
Frank -
Pay attention, please! I already wrote all of this above - there ARE NO MORE IDEAS.
And I was assuming, perhaps wrongly, that you would have read my posting " VERY IMPORTANT - Filtering Air, OIL, and Morons" - read it again.
Your engine mounts ARE JUNK - the top and bottom plates are parallel if the mount and brackets are good. That will raise the engine considerably, and if the (current) left mount is worse than the right one, fixing them WILL tilt the engine to the right.
The K&N will fit just fine, but note my suggestion of a spacer behind the filter instead of the stupid thick gasket.
Those foam filters are not as bad as the S&H ones, but they are a near second, They are very little better than NO filters and kill performance. I have a lot of experience cleaning carbs on routine maintenance - the filth from these is the same as with NO filters. You have $ xxxx in your car, and it will cost you more than that to replace the engine when this junk kills it - spend the $130 to save the poor thing's life, save you gas. wear, and aggro.
FRM
Thanks so much for that reply, Fletcher. The plates on the right side mount are parallel. The left side mount lacks about 3/16" of being parallel. Is that too much? I did read your posting on filters, and I respect your opinion and your experience - however, I know of many MG's down here that are running the type of filters I bought with no problems over a period of years. Once I get this car running again, I plan to invest in the K&N's. I had one on the ZS and I have used them on other vehicles as well. I also know that regular maintenance is the lifeblood of any vehicle and I planned to clean the foam filters regularly until I could get the K&N's. BUT, I am not paying that kind of money until the car is up and running and I can be reasonably assured that they will fit. If you read the whole thread, you will see that one other member had a problem with K&N's fitting.
Frank
Frank,
If it is helpful, I can mail you one of the conical filters to test fit. That way you can get your car setup correctly while you are working on it. Once satisfied, just send the filter back to me.
Thank you, Jimmy. That's a very generous offer. Let me see if I can get this one to fit. I know it should. I've seen them on many other RB cars.
Thanks again,
Frank
FRank,
I think you should buy a new set of engine mounts and replace the old ones.....I didn't find the project too difficult but there are tricks to making replacing them easier....
Frank-
I did read the whole thread - we are not interested in how many cars are wrong, we want to fix yours. I've done a hundred mount repairs, and it fixes the problem. Think of the engine as pivoting on the RH mount; if the LH is low, it brings the carb down and left,- I've seen them in contact with the booster, and that's where yours will be when the mount bracket breaks as it will. Replace the brackets and mounts in accordance with my instructions above.
I've been caring for these cars since 1966, the foam filters DO NOT filter, for the reasons given in my post on that. I know there are many people running them with "no problem" and there are equally many rebuilding engines at 25% of the mileage you can reasonably expect on a B.
FRM
Just to be ornery, I suppose you could get along without the power brake system. Removing the Booster and M/C and replacing with the previous dual line cylinder doesn't seem like it would be too hard to do. And then, you'd have your clearance. But then, I never quite understood why MG felt obliged to install power brakes on the non V-8 cars in the first place.
Thanks again, Fletcher. The idea of the engine pivoting on the RH mount makes sense to me. I just wasn't looking at it from that perspective before and it seemed like raising the left had side would bring the bottom of the filter even closer to the booster. On the '75, the steering shaft runs through the bracket that the mount bolts to. Is it necessary to remove the steering gear to replace the mount? Will I cause myself even more time and trouble trying to work around it?
Interesting idea, Bob. I had a '67 B and never had any trouble stopping it. Sometimes simple is better!
Thanks all,
Frank
Marc, I'd be glad to hear anything that might make this job easier. It looks to me like it's going to be a knuckle buster.
Frank
Frank-
You can usually change the mount with the rack in place, but not fun. 6 of one and the other half dozen of the other... Sometimes the rack mounts are bent and the rack MUST come out, OK because you have to remove it to fix the rack mounts anyway.
Be sure to read my instructions on prestressing the new mounts, and the correct position of the lower stud in the slot, posted earlier. And DO NOT try to save by not replacing the brackets!!
I just looked at a car with a header - the mounts/brackets are so bad that the steering shaft is holding the engine up - must be fun to drive!
FRM
I was just re-reading your earlier post about prestressing the bracket. I did order the bracket, too. There's not a whole lot of room to work, is there? I'm going to spray everything down with penetrating oil and let it sit while I wait for the parts.
Frank
Here is how they fit in my '78:
I also added the APT stub stacks inside, note the modification to the bottom so that the air filter could be put in place.
Eric, I think that is as good as a car with SU's and a brake booster can be set up. That is exactly how I have both my 79 and 80, although both have HS4's.
Gofanu Wrote:
JimmyHilton Wrote:
Has anyone ever made a box to bolt to the carbs with a filter mounted somewhere near the front with the air fed through a tube? What would be the disadvantages of this set-up?
The Wiz Wrote:
JimmyHilton Wrote:
Mike,
Well, you didn't even have a brake booster on that car. Now there is is the real solution!! That would be far easier to get rid of than trying to figure out where to mount the steering wheel on the other side ........
I have pondered endlessly on how to make a decent air box, that was fed by a forward mounted filter. I don't think it is impossible, but an economical and reproduceable solution has not hit yet. A big part of the problem is that even in mounting the carbs, there can be 1/16" or so difference every time they are mounted. Makes a nice backplate kind of a moving target. I think the only viable solution would be using the original SU filter backplates/stubstacks and making a backplate that integrated with them. And then a very unusual shaped cover.
JimmyHilton Wrote:
JimmyHilton Wrote:
Eric-
Well my home is my shop, and there's a lot of junk, including machine tools and materials.
Certainly, I'd love to sell some, but I'd probably have to make you some stub stacks to go with - I didn't on the one I just had because he is cheap and drives slow. Can be aluminum or Phenolic (or gold!), depends on what you want and what I got - or get.
If I could get just the K&N elements, I'd make the whole filter backplates, correctly.
In any case, it'll be cheaper than just the stub stacks from others.
PM if you or anybody really want some - I'd be more than glad to make a couple pence to spend on more toys! Toys are like children, but they hang around longer staring at you with sad eyes - "I need some goodies".
Mike -
Not a big problem to make an airbox, with remote filter, and some good reasons to do so. It takes some space and a 4" hole in the Rad support panel. Like most things, a bad one is easy, a better one is harder, and a really great one could be a lifetime task. The OE filters are effectively free, work just fine, and are easily modified for more air, but that's only necessary for really hot engines.
FRM
Okay, I've nearly got everything off. I'm letting one stubborn bolt soak in the GM penetrant for a while longer and I still need to crawl under the car to get the mount off, but there's nobody home but me right now. Even with jack stands and chocked wheels, I like to have someone else here if at all possible before I get under a car. If for no other reason, I don't want to be the only one screaming if it falls! Now, to business. When I get ready to put this back together, is it easier to put the mount on the body side bracket and try to line it up with the engine - or put it on the engine side first and try to lower it gradually until it lines up with the body side?
Thanks,
Frank
Frank-
You must bolt the mount to the engine bracket, making sure the offset stud is down, then lower the engine so the stud goes in the slot. Then put a little weight on it and tap the stud to the bottom of the slot, and fit the square washer, again hole offset to the bottom. That loads the mount correctly, and it would not be possible to get the bolts in the mount to bracket holes in that position. If the stud is not at the bottom. you can't fit the square washer and the mounts will fail quickly - and the damn engine will not be in the right place STILL!
We wanna see pics of it all together!
FRM
Thanks, Fletcher. I was wondering which way the offset bolt went. I was gonna put a paint dot on top of the old mount to make sure the new one went in the same way - but there's no guarantee it's in right! Now I know the right way. I was going to leave the mount to engine bracket bolts loose to facilitate positioning the mount, but it sounds like that might not be necessary.
Frank
It looks like there's bad news and worse news for me. I got the engine bracket off. Other than having a lot of dirt and grease that I had to clean off, it is fine. There are no cracks or bends. It exactly matches the new one. The worse news is that when I reach into the underside of the chassis bracket to feel for the mount stud and nut, all I feel is steering shaft, and the mount has separated from the backing plate ( the one with the offset stud).
Frank
Frank-
From your picture way back, the mount bracket IS bent, or the frame bracket is - they must be dead parallel with the engine at the design position. Is there sign of accident damage?
Couldn't say where the stud and nut are - jack up the engine and the lower mount plate should just fall out - if not, then the stud must be there - or it's been glued! Hopefully not electric wrench glued...
Leaving the two upper bolts loose can help in fitting the thing, but the bolts should be in place when the bracket is bolted to the engine.
FRM
You won't be able to feel the stud with your fingers, it's behind the steering column. Poke a 9/16 spanner up in there and you'll be able to feel it then.
Wiz, if I can't feel it with my fingers, how in the world am I supposed to get the nut on the new mount?
Fletcher, I'll send a couple of new pictures.
I really appreciate you guys sticking with me this long.
Frank
Like this:
http://www.mgexperience.net/phorum/read.php?1,555837
Unless you want to pull the steering rack put the mounts on the body first, leave them a little loose so you can move them around then tighten them fully once the engine is in and everything is settled into position.
Don't throw those old mounts away yet, you may need some shims to get everything to sit right and the top plates on the mounts are perfect once you have cut them off the rubber.
Thanks, Mike. I was going to put silicone on the plate to hold it in place. I like the duct tape on the wrench idea. That sounds like it might work. I don't see how he did it without putting it up on stands though! I can barely get my shoulder under mine without stands. I especially like the neighborhood kid idea.
Frank
Frank-
Hard to see in the 004pic, but that frame mount looks bent - examine carefully and maybe give us some more pics??
FRM
It's possible, Fletcher. I know it was hit in the front at one time, but I don't know how hard. Still, it's all I've got to work with. I saved the old mount so I can try Mike's advice about using the old backing plate for a shim. I'll see what I can do about getting a better picture. I've been fighting bronchitis all week or I would have answered sooner.
Thanks,
Frank
Frank-
What, can't type with bronchitis? - just kiddin', get well fast!
The area where the mount sits should be flat, and in the pic it looks maybe not so.
Another issue raised in another post on the subject is that the '75 only may have something different about the booster size/position. I haven't run into this, so can't say for certain, but the servo for 74 1/2-75 cars is different than the later ones. Might have to get a later servo or throw the thing out and revert to the perfectly good non servo system.
FRM
The only way that the method in the link works is with the engine out. With the engine in, every time you try to thread the mount onto the nut, you hit the plate on the front of the engine. I've just been trying that method for the the last two hours. I'm about ready to sell this thing and get a nice 4cyl Chevy.
Frank
Oh yeah, there isn't a square washer inside the body bracket, and if there were, there's no way to get a wrench up there with a nut taped to it. The wrench almost doesn't fit now.
Frank
The more I look at that pic, the more I think the frame bracket is bent. And maybe cracked, and looks to have had heat on it.
If there's no square washer, just make sure to follow my instructions - the stud winds up all the way at the bottom of the slot.
If anything is bent, then you won't be able to get in there. Pull the rack out, save yourself all this aggro. Look for more bent parts, check that the steering shaft is more or less centered in the hole in the frame bracket - I've had cars where the rack mounts were bent sideways, making it flat impossible to get the motor mounts in. The rack mounts bend laterally very easily, and straighten the same. Check the rack mount welds for cracks too.
FRM
If you're going to pull the steerring shaft, here's how I do it, it's a 15 minute job and you don't have to deal with the tie rod ends or alignment issues, un-do the bolt on the steering u-joint right after the steering shaft exits the firewall, un-do the sterring rack mount bolts and instead of messing with the PITA tie rods, un-do the the steering arms from the uprights/spindles.
Fletcher, I just checked the rack mounts and they are straight . The shaft appears to be more or less centered as best I can see from the front of the car. I believe you are right about removing the rack. I've tried to work around it long enough. I could have been through by now if I had removed it to begin with. I did think about it but thought I could avoid it. I really do know better than that. One thing I learned working in parts and service for GM was that if something is in the way it's usually quicker and less stress to remove it than to try and work around it. It's a shame I had to relearn it!
Thanks again,
Frank