Pushrod Popped off*** UPDATE with PICs : MG Motorsports Forum : MG Experience Forums : The MG Experience

Re: Pushrod Popped off*** UPDATE with PICs #61
Benny Ben E San Diego, CA, USA 1961 Austin Mini 1964 Ford Cortina 1964 Land Rover Series IIA 1965 Ford Cortina 1965 MG MGB → more	Posted: August 19, 2012 02:53PM Registered: 7 years ago Posts: 3,465

I just looked an the Flowspeed head that I have bubble-wrapped, and waiting on-deck for my car. The keepers are sitting at several different heights, but none are as extreme as Paul's....none of mine sit down flush, yet none are protruding anywhere near as far as his worst offenders.

Out of interest, I pulled out my spare early head with stock (factory) early hardware, and there was a fair amount of variability in those also, including some pretty large gaps (see pic). This head was rebuilt by an unknown shop long before it fell into my hands.

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Re: Pushrod Popped off*** UPDATE with PICs #62
Filth and Greed Motors Paul Gaylo Corning, NY, USA 1959 MG MGA 1500 1970 MG MGB GT	Posted: August 19, 2012 06:32PM Registered: 5 years ago Posts: 1,379

I just got back from my engine guy. All of the guides have been reamed out to .003 clearance. Three of them were way too tight, less than a thou of clearance. They feel much beter now. I was advised that was insane to run the teflon seals on the exhaust and that is propably the root cause of a stuck valve. I was also given a different type of seal for the intake that lets a little oil through.

The keeper situation is a disaster. The keepers from moss must be for a 5/16" stem midget valve or something. I have a mix of parts, at least three different versions of the same cotter All the keepers, whether from flowspeed or moss, are unuseable.

My engine guy lapped in the valves again and they look okay. The contact area is larger than it needs to be but it will work.

The only good news was that the porting looks really good.

I will call APT in the morning and see if they can supply quality hardware, but I bet they are just using moss parts too.

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Re: Pushrod Popped off*** UPDATE with PICs #63
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: August 20, 2012 06:05AM Registered: 7 years ago Posts: 20,332

Paul, the teflon seals didn't cause the failure, a bronze guide could care less if it lubricated, or not, but there is no reason to run them on exhaust valves, none watsoever. What caused your failure is the guide clearance, or lack of it. I've see this many, many times on our cars at the race track, even one time I let a Chevy engine builder who is genius talk me into tighter guide clearance, and my trail of destruction was far worse that your's, I took out several push rods, lifters and destroyed a very nice race cam. This is the thing I talk to alot of machine shop people about for my engine rebuild kit customers with the most, and machinist often times want to argue with me about this, and I always tell them, if they are comfortable with doing a warranty for the customer to prove their point, to proceed, and do it their way, and that nomrally gets their attention. I deal with this issue with machinist nomrally several times each month, that's how common this is. You siezed an exhaust valve on the guide, plain, and simple, and you got away with it for the most part with minimumal damage, had the rpm been higher at the time of failure, the trail of damaged parts would have been much higher.

Hap Waldrop
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Re: Pushrod Popped off*** UPDATE with PICs #64
BlueMax1 Alan Gilbert Powdersville, USA	Posted: August 20, 2012 06:49AM Registered: 1 year ago Posts: 222

I agree with you Hap; Most machinist will install guides and not even think of the expansion coefficients of the alloy that their installing. Machinist install 95% of the time cast iron and the guide tolerance reference books instruct you to ream with X reamer. And here lies the problem and why. Clearly the difference in the expansion coefficients, big difference!! http://www.repairengineering.com/coefficient-of-thermal-expansion.html

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Re: Pushrod Popped off*** UPDATE with PICs #65
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: August 20, 2012 07:00AM Registered: 7 years ago Posts: 20,332

In reply to # 2149690 by BlueMax1 I agree with you Hap; Most machinist will install guides and not even think of the expansion coefficients of the alloy that their installing. Machinist install 95% of the time cast iron and the guide tolerance reference books instruct you to ream with X reamer. And here lies the problem and why. Clearly the difference in the expansion coefficients, big difference!! http://www.repairengineering.com/coefficient-of-thermal-expansion.html

Yep, it's not that bronze guides are new to them, they are not, it is the wall thickness that gets them, and the siamese exhaust port that fools them on heat. It's not that they are stupid, far from it, it just a booby trap waiting to get them, a booby trap that has already got most of us, and that's the only reason we know this, and they don't. A really smart person is he who can see a booby trap waiting for them, and react, and I have not met many people like that, we all almost learn from example. smiling smiley

Hap Waldrop
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Re: Pushrod Popped off*** UPDATE with PICs #66
Benny Ben E San Diego, CA, USA 1961 Austin Mini 1964 Ford Cortina 1964 Land Rover Series IIA 1965 Ford Cortina 1965 MG MGB → more	Posted: August 20, 2012 04:33PM Registered: 7 years ago Posts: 3,465

Hap,

What do you think the root cause of these variable keeper heights is....part quality? And if so, is it something to be highly concerned about?

Do you have a source for hardware that you have been happy with?

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Re: Pushrod Popped off*** UPDATE with PICs #67
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: August 20, 2012 05:12PM Registered: 7 years ago Posts: 20,332

In reply to # 2150108 by Benny Hap,

What do you think the root cause of these variable keeper heights is....part quality? And if so, is it something to be highly concerned about?

Do you have a source for hardware that you have been happy with?

Ben, I've never seen that before, I have a half dozen assembled heads in the shop right now, race and street and none of them have varying keeper heights like I'm seeing on Pauls's head, and my race head is on the head bench right now and I use the new steel late model MGB narrow groove collet style dual psring retainers , Gordon at the B Hive got them for me, and I'm sure they come from the same folks Moss gets them from as well. In the past I got keppers from BPNW, because they have really good price on them, and there again, I'm sure everyone is getting them from XRN ("County" winking smiley

, they are probably the only ones having them made for our cars, unless other cars use the same part. Dave H. uses a a different valve and retainer package,, different as, in non MGB, and I have one of Dave's head here as well, and they sit slightly coutersunk in the retainer Dave uses, and all seem to be the same height as well, also Scott's Huffaker heads are here as well, I just peaked at them, they are waiting to be crated and shipped to him,and I looked at them they have a big ole honking valve spring on them, that I put on them at the advice of Tim Mountjoy about 25 years ago, and while dfferent retainer,and all equal, sometimee the keeper are slightly different height from one head to the next depending on the retainer, everything on all of these given heads is the same, as for equal keeper heights on each head.

.

Hap Waldrop
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Re: Pushrod Popped off*** UPDATE with PICs #68
Filth and Greed Motors Paul Gaylo Corning, NY, USA 1959 MG MGA 1500 1970 MG MGB GT	Posted: August 20, 2012 07:43PM Registered: 5 years ago Posts: 1,379

I talked with ATP today and they agreed that the replacement cotters from county are pretty bad. They wouldn't sell me any originals as they needed them.

I wonder if Dave H. uses different valves with a different groove. If he uses MGB valves, maybe I can just get a set of springs and keepers from dave.

There is no way I am going to use the repro county stuff. I tried some chevy 350 stuff and it fits perfectly on the mgb valve, exactly how I want, however the retainers don't fit the spring.

I have 4 more days to figure this out.

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Re: Pushrod Popped off*** UPDATE with PICs #69
Steve64B Steve Opitz Phoenix, AZ, USA 1966 MG MGB	Posted: August 20, 2012 07:59PM Registered: 6 years ago Posts: 8,347

In reply to # 2150246 by Filth and Greed Motors I talked with ATP today and they agreed that the replacement cotters from county are pretty bad. They wouldn't sell me any originals as they needed them.

I wonder if Dave H. uses different valves with a different groove. If he uses MGB valves, maybe I can just get a set of springs and keepers from dave.

There is no way I am going to use the repro county stuff. I tried some chevy 350 stuff and it fits perfectly on the mgb valve, exactly how I want, however the retainers don't fit the spring.

I have 4 more days to figure this out.

Get springs to match the retainer! There are a TON of options with GM based parts. I would think it would be easier to find a spring that gave a seat and nose pressure that was acceptable. Hell the bottom of the spring just needs to be flat!

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Re: Pushrod Popped off*** UPDATE with PICs #70
FTD in an MGB Ed Sweeney Philadelphia, USA 1958 MG Magnette ZB 1968 MG MGB GT	Posted: August 21, 2012 07:11PM Registered: 8 years ago Posts: 2,454

I had the same problem with Moss parts not fitting my stainless valves from APT. Dave supplied me with cotters that were supposed to fit but they were also pretty poor and had to be returned. We ended up finding a small-block Chevy part from Pep that fit perfectly within the original retainers and solved the fit issue. I can look for a part # tomorrow. Forgive the appearance of the retainers, historically significant build so the owner wanted to retain as many original parts as possible.

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Re: Pushrod Popped off*** UPDATE with PICs #71
dickmoritz Dick Moritz Philly 'burbs, PA, USA	Posted: August 21, 2012 07:21PM Registered: 3 years ago Posts: 7,266

Ed,

Very pretty... thumbs up

It appears that you're using the early style valves with the wide keeper grooves, since some of your valves appear to have the early style collets with the hairpin clips, and these are characteristic of the early valve -- possibly MGA or Magnette? Paul is in need of the later style collets and retainers with the narrow groove for the keepers...

Dick

Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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Re: Pushrod Popped off*** UPDATE with PICs #72
Filth and Greed Motors Paul Gaylo Corning, NY, USA 1959 MG MGA 1500 1970 MG MGB GT	Posted: August 21, 2012 07:30PM Registered: 5 years ago Posts: 1,379

Ok, I think I secured a set of original keepers so that issue is solved for the moment. In the future I am not going to go down this road again. I talked with my engine guy and I think I would be much better off using different valves/springs/retainers/cotters and try to do the valve like a system...exactly what Dave H was saying earlier...

I am not going to run exhaust seals, and I have a non-teflon umbrella seal for the intake that was recommend by my engine builder friend.

I think I am set now. I will post pics this weekend.

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Re: Pushrod Popped off*** UPDATE with PICs #73
FTD in an MGB Ed Sweeney Philadelphia, USA 1958 MG Magnette ZB 1968 MG MGB GT	Posted: August 21, 2012 07:32PM Registered: 8 years ago Posts: 2,454

Dick,

Of course you are correct, my mistake! However I still think you should check out Pep - they have a good selection of valve components and most importantly, they fit! We went through this whole process with multiple retainers and cotters and Pep solved our problem immediately. Spec out your groove design, height, and taper and you should find the right one.

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Re: Pushrod Popped off*** UPDATE with PICs #74
Rick Starkweather Raleigh, NC, USA	Posted: August 21, 2012 08:55PM Registered: 8 years ago Posts: 697

From my crew chief:

We've had the following issues with 1.625 ratio H/S MGB rockers:

a) They cause the pushrods to rub on the head
b) We broke one at the machine/oil drilled hole (weak area)
c) We've trashed the bushings and had them rebushed.

They have since redone the 1.625 ratio rockers so that there is a little more tip length (and subequent adjuster end length) so that the pushrods clear. We now run this "redone" set, rather than the first set which had both problems "a & b".

Still not sure why one of the rockers broke. It's possible it was a consequence and NOT the cause of the failure. (There was a cam/lifter issue at the same time as well.)

They've done a very affordable rebush of the rocker set for us (~$50 for the 8). I don't think the failure of the bushes has much to do with H/S-- it is more likely there was some debris still trapped in the rocker shaft that worked itself loose. Still, knocking them out showed that the bushes weren't all drilled to line up with the oiling groove squarely.

Really, our only concern was the pushrod rubbing. I run the "redone" style of set in my own road car and have had no problems. (Though I rarely go much above 5K rpm...)

d) They take some "fettling" to get to fit correctly. But any performance rocker has the issues of proper geometry, and the "fettling" was mainly because we run the reinforced pedestals and the metal spacers (instead of springs). So, not sure that's a fair knock agains the H/S rockers themselves-- just something you kind of figure out for yourself when assembling your rockers!

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Re: Pushrod Popped off*** UPDATE with PICs #75
rhinsb Rich Hagon Santa Barbara, California, USA 1971 MG MGB GT "Money Pit"	Posted: August 21, 2012 10:34PM Registered: 6 years ago Posts: 1,168

Thanks Rick, I just checked my pushrod clearance with my machinest
and I can at least see light between the rocker and the PR. HS used
the original bushing material for mine. I hope that works out ok
with the hardened shaft. Thank God for this site and all of our pros
that help us through all the fixes we get into. smileys with beer

Sounds like you
have a handle on this Paul. Keep us up to date on how it works out.

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Re: Pushrod Popped off*** UPDATE with PICs #76
dickmoritz Dick Moritz Philly 'burbs, PA, USA	Posted: August 22, 2012 07:50AM Registered: 3 years ago Posts: 7,266

In reply to # 2151041 by FTD in an MGB Dick,

I still think you should check out Pep - they have a good selection of valve components and most importantly, they fit! We went through this whole process with multiple retainers and cotters and Pep solved our problem immediately. Spec out your groove design, height, and taper and you should find the right one.

Thanks for clarification and recommendation, Ed. Forgive my ignorance; are you referring to Philly's own Pep Boys, or is there another Pep around that I'm not familiar with. Apparently I have less "Pep" as I get older... eye popping smiley

Cheers,

Dick

Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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Re: Pushrod Popped off*** UPDATE with PICs #77
fast-MG.com Dave Headley Cortez, 4 corners, Colorado, USA	Posted: August 22, 2012 08:24AM Registered: 4 years ago Posts: 3,241

Dick, PEP=Precision Engine Parts, Las Vegas NV. www.precisionengineparts.com, 1 800 423 2202.

How to advertise on this website

Fast-MG.com Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.

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Re: Pushrod Popped off*** UPDATE with PICs #78
dickmoritz Dick Moritz Philly 'burbs, PA, USA	Posted: August 22, 2012 08:43AM Registered: 3 years ago Posts: 7,266

Thanks, Dave. I couldn't imagine a chain like Pep Boys having anything worthwhile other than fuzzy dice... cool smiley

Dick

Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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Re: Pushrod Popped off*** UPDATE with PICs #79
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: August 22, 2012 09:05AM Registered: 7 years ago Posts: 20,332

In reply to # 2151023 by FTD in an MGB I had the same problem with Moss parts not fitting my stainless valves from APT. Dave supplied me with cotters that were supposed to fit but they were also pretty poor and had to be returned. We ended up finding a small-block Chevy part from Pep that fit perfectly within the original retainers and solved the fit issue. I can look for a part # tomorrow. Forgive the appearance of the retainers, historically significant build so the owner wanted to retain as many original parts as possible.

FWIW, normal larger than stock valves for the MGB coming from the normal British parts vendors, if you go with a intake valve of 1.625, or the 1.690" on early head, you have to convert to the later narrow groove collet/keeper reatiners and collets, becasue the larger intake valves (which are common to all vendors, APT, or not) are only offered in the narrow groove later collet style. These parts cannot be interchanged. Every early MGB head I modify, get the later narrow groove style set up, so I can use the larger intake valves.

Hap Waldrop
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Re: Pushrod Popped off*** UPDATE with PICs #80
balloonfoot Lloyd Faust New Mexico, USA 1964 Porsche C Coupe 1967 MG MGB "MAX" 1985 Chevrolet Corvette "EASY 1ST" 1986 Chevrolet Corvette "Gas Mileage Special" 1989 Chevrolet Camaro ""I Rock""	Posted: August 22, 2012 09:58PM Registered: 4 years ago Posts: 8,291

I have read this entire thread and have a question. Are there some rules you guys adhere to where it says you must use valve train pieces that are made in England using the original BMC design? I have always found that English stuff is high priced, poor quality and outdate design. I don't get it. Please explain.

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