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MG TD TF 1500 More Laystall head issues. TD4834 BBS discussion at MG-Cars.info
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MG TD TF 1500 - More Laystall head issues. TD4834
| I've been puttering in my TD a few minutes at a time as I continue to recooperate from my heart attack. Yesterday when I started the car there was a loud snapping popping sound from the engine. I immediately shut it down and began to investigate. Spun the motor over with the ignition off and it was still present. As I turned it over several times with my hand in the starter and the block I could feel a very sharp resonance from within. No windows in the block or oil pan so that was a good sign,I hoped. I then pulled the plugs. All were dry and dusty, sooty. Spun it again and the noise persisted. I then pulled the valve cover and found a rocker adjustment had backed off. Hmmm. Ran it down and spun it again. That's when I found the noise. The number one intake valve was sticking open and the noise was when it would slam shut. This morning I found number two doing it as well. I'm reasonably certain it is varnished race fuel causing the problem. I was hoping to find a way to unstick them by shooting brake clean or some other solvent onto the valve stems in situ to free them up but with my header there isn't a straight shot not could I get enough in the right spot to clean the stem. In addition I have a porosity issue to deal with as well so I am going to pull the top end apart and send it back to the machine shop for further inspection and repair Bill Chasser jr TD4834 |
| W. A. Chasser Jr |
| In addition , I realize that there has been no topside oiling for the few minutes that it has run. I was certain I installed the rocker assembly correctly but will pull the end pedestal and verify the shaft placement. Are all the pedestals drilled for oiling? I may have the wrong pedestal in place at the rear I was sure I placed the shaft correctly but will double check it again as well Bill Chasser jr TD4834 |
| W. A. Chasser Jr |
| Bill great that you are doing much better! Please call or E mail me. Best Len |
| Len Fanelli |
| Make sure the rear pedestal is drilled for oiling; stick a wire up it and verify that the shaft is correctly oriented. My opinion is that with their dimensional differences, and higher compression ratios, that Laystall heads should stay on the track. Tom Lange MGT Repai |
| t lange |
| Tom. This car will see competition from time to time. Certainly this head has given me ol enty of headaches through out this build. Though I have the original ironhead freshly rebuilt, I chose to put the stock valve springs back on it rather than install my roller kit springs which I still have boxed up. I didn't want to do port work on my original head and without it being reworked doubt it would work well with my choice of camshaft. "Make sure the rear pedestal is drilled for oiling". Are not all pedestals drilled or are they in fact positional? Regards Bill Chasser Jr. TD4834 |
| W. A. Chasser Jr |
| Hi Bill, I have never seen an undrilled pedestal but agree that you should check. I have come across some weird things .... some of which must have come from the factory! Have you had the rocker gear dissembled? The shaft can be fitted upside-down but that results in the supply hole (in the shaft itself) being at the top of the front pedestal, resulting in zero oil supply to the rockers. I actually run my shafts upside down to get the oil supply on the load side of the rocker bushes BUT to do this I have to drill a new oil supply hole in the shaft. Have the guides been reamed with insufficient clearance? I once had that problem. Good to hear you are recovering well. Good luck solving the problem. Bob Schapel |
| R L Schapel |
| Assuming you get the oil problem fixed, have a look at a few Youtubes on getting stuck and sticky valves to behave. You may not need to pull the head. http://www.youtube.com/results?search_query=stuck+valve ...... |
| MAndrus |
| What kind of valve guides are installed? It bronze guides were used, they need to be opened about an extra 0.001" to allow for expansion. Cheers - Dave |
| DW DuBois |
| Old timers had something to offer. An old mechanic told me that after installing valves in a head you should take a ball pein hammer and give each valve stem top a good rap. This does two things it proves the valves are free to travel in their guides and also ensures the valves are seating. |
| G Evans |
| Yes, When I had sticking valves, the guides were bronze and just needed a whisper more clearance. I found that common BMW bronze guides fit T-Types perfectly! They even come in a few over-sizes to cater for damaged alloy heads. The hardened XPAG shroud (inside the inner spring) needs to be cut back to clear the BMW guides but that is a common weight saving mod anyway. The BMW part number is 81-1148 and they fit older 6 cylinder models. They were $6 each when I fitted them to my TC in 1988. Bob Schapel |
| R L Schapel |
| Bob and Dave Though I can't tell you what the guide clearances were off hand they were reamed to fit the MK II valves. The new guides were not the standard TD pieces because if memory serves me correctly the previous guides were modified on the OD for some reason. We did not use bronze guides on the recommendation of both Lawrie Alexander and the machime shop. Both saying that the bronze guides would not hold up well. Guides were machined for the Perfect Seal valve stem seals. Mitchell. I went to the YouTube page you marked but found nothing on the page related to stuck valves. Because of the porosity issue the head will be coming off to address this issue as well I will know more tomorrow when I get the head off. Regards Bill Chasser jr Td4834 |
| W. A. Chasser Jr |
| Dunno... I couldn't get the You tube search link to work. http://www.youtube.com/watch?v=emZnew57Guc This one is absolute genius: http://www.youtube.com/watch?v=-ZQRqyTjuPc ...... |
| MAndrus |
| When using the bronze guides I enlarge them by .0003"- .0004". Also when installing a valve, before the spring is installed, it is good practice to put the head on its side, & smack the valve with your finger, it should bounce off the seat, if not it is jamming on the seat and not seating correctly. "An old mechanic told me that after installing valves in a head you should take a ball peen hammer and give each valve stem top a good rap. This does two things it proves the valves are free to travel in their guides and also ensures the valves are seating" It also ensures that the locks or keepers are not about to fly out. |
| Len Fanelli |
| Got the head off this morning and as I suspected the varnish had caused the valves to stick. Stick so much in fact the the shop reported that the guides had been forced up and down in the casting. Even though. I had flushed the tank out with solvent. The shop insist that it is old gas varnish though I find it very hard to believe. The tank has been empty for nearly 50yrs and I can't imagine that much varnish built up in the 7 odd years the car was actually in service. The inside looked visually clean and rust free prior to my solvent rinse. I still think it is the race fuel's toluene setting in the carbs For a lengthy period is the culprit as very little residue came out in the flush and it didn't smell like old fuel. Moral I guess is to boil the tank at the radiator shop before painting. The porosity issue is yet to be addressed and I haven't disassembled the roller rocker assembly yet. To hot outside and feeling flush Bill Chasser jr TD4834 |
| W. A. Chasser Jr |
Bill, I almost hate to comment because there are so many experts out there, but I would hate to see you have the same problem again. I've been there and done that. So, possibly consider: You reported lack of oil in rocker area (that's where the valve stem gets oiled). You reported using positive valve seals(They are great at stopping oil burning, but also are restrictive to oil flow to valve stems. Your fuel would really have to be sticky to stop valves from moving in an oiled guide. You reported that the valves in question are intakes, well, is the guide clearance the same for your intakes and exhausts? Normally the exhaust needs a little more clearance for heat expansion. So if the intakes are tighter, I'd guess they could be first to stick without oil. My thought is your problem is possibly more related to stem clearance and lack of oil getting to the valve stem. Finally Bill, I know your aware of the importance of cleaning engine parts before assembly but let me tell you from experience, ANY dirt or machine grit in the valve stem/guide area and your in trouble. After all these years, I refuse to let any machine shop assemble my valves to the head. I can tell you it is impossible for them to do perfectly clean assembly in the same place where they machine parts. It takes me a lot of time to check all of the parts fit and clean everything before putting in the valves, but not near as much time as I've spent over the years by tearing down engines when I let them do it and a valve stuck. |
| Richard Cameron |
| Len, and G Evans, You guy's are so right the "the old blokes were not stupid by giving the valve stem a hammer wack or 3 each . Have done that all the time during a head overhaul ( me 70 years old now LOL ) Gerard |
| Gerard Hengeveld |
| Richard, of course you are right in re to the lack of lubrication. With out oil to cool the valves and guides it certainly was a big contributing factor to the failure. I'm sure along with the lack of oil, the heated stems when in contact with fuel instantly evaporated the solvents and left the sticky goo clinging to the valve. I actually did the head assembly in the clean room when doing the engine build as we were still dealing with trying to get a suitable spring to work with our Laystall. It had an installed height of 1.50 vs the normal 1.750-1.830. Everything about this particular head setup has been frustratingly peculiar. You would need to do an archive search to get the whole story on it. But when the final assembly was done every individual piece was inspected, douched with BrakeKleen and dried with compressed air before moving parts were coated with moly lube prior to assembly. Had I relied solely on the oil impregnation of the rocker bushings I don't doubt they would have seized as well. Tomorrow I will disassemble the rocker shaft and inspect it to determine why there is an oiling issue. The passage in the head to the pedestal was clear. You also asked if the clearances on the guides were correct. To that I can only defer to the shops expertise on that one. This particular shop is the "go To' shop for MG machine work. They are very knowledgeable and probably get 2-3 xpags every month along with the B engines they get weekly. They are highly recommended and well trusted. Len and George, I'm not grasping the concept of the ball peen hammer. Len I will try to contact you tomorrow afternoon. Regards Bill Chasser Jr TD4834 |
| W. A. Chasser Jr |
| I've been thinking about this a bit. I remember something my auto shop teacher said back in the 70's (when auto shop was still taught in HS), leave race car parts on the track, use OEM to fix the family sedan. The reason is clear. Race car parts are designed to get beat to piss and replaced after a race or two, maybe a few thousand miles, family sedan manufacturers design parts to last a while longer (snickering aside). Valves are designed to be rotated as they work for a few reasons. Build-up is wiped off the mating faces, heat is evened out as different areas move to hotter/cooler spots in the head, wear is spread around the face evenly, build-up on the stem is less likely to cause linear scaring, oil is distributed on the stem more evenly. Rotating the valve requires a certain amount of friction that can only come from the rocker's mating face. Putting a roller at this critical interface is what they do in race cars to cut friction. In a race car engine designed to last a few hundred miles nobody cares about long term problems. But, both race car and street engines need oil to get to the guides. O rings, rubber caps, closing the small weep hole with a screw... all prevent oil from getting to the the valve stem. I don't know if you have rollers on the rockers, but I would think hard about using them long term. For the lack of friction, they are not going to turn the valves as they need to be turned. Flat tappets are also designed to rotate and cams are ground differently for flat vs roller tappets.... different discussion. Is there ANY way to get oil dependably to the valve guides in your setup? Weep holes, oil galley to the mating surface...? I think once you get the valve/guide clearance sorted (easily done) you must make sure you are rotating the valves and getting oil to the stems.... as the OEM parts do. ..... |
| MAndrus |
| As an aside, it may be impossible to stop a valve from rotating. Modern engines with better designed valve and seat materials may simply allow the valve to do it's thing as better compression chamber designs force gasses to assist this movement. There are some excellent papers available on this. .... |
| MAndrus |
| I am seething mad. Because my rockers weren't oiling properly the valves overheated and began seizing in the valve guides causing at least two guides to be pushed in and out of the head from the cam lift and then by the springs. The shop has told me my precious head is now certainly rendered junk. I spent an enormous amount of time, energy, busted knuckles not to mention money on this set up. Close to $3.5K out the window for 10 mins of run time. Now i'm without a head that matches my Arias pistons profile.. The car is dead until I can come up with another casting. I will call George Edney tomorrow to see if they are even still producing them. B & G says limited quantity on their site. I'm beginning to think this car hasn't been on the road for over 50 yrs for a reason. 3 POs couldn't make her run and now 4 owners. This car is Satan incarnate. AAARGH! If anyone has a spare Laystall that isn't a "POS" and has no need for it please get back with me. Bill Chasser Jr TD4834 |
| W. A. Chasser Jr |
Bill, I know your about to give up on it but there are a lot of viable solutions to correct problems with aluminum heads. Remember a lot of present day passenger car heads are aluminum and there are specialty shops that deal with them all the time. For example, your aluminum head guide bores may be bored over size for larger diameter bronze guides chilled and installed. Can you tell us on the forum why the head didn't get oil to the rockers in the first place? |
| Richard Cameron |
| Robert. Unfortunately the guides have been oversized +.010 already due to a POs previous machining. They will have the head completely stripped on my insistence tomorrow and give me a full assessment at that time but they a skeptical at this point given there initial findings. Re the oiling issue to the upper end. I had +60 psi at the gauge measured at the head port so naturally I assumed they were oiling properly. I can see four scenarios as to why oil wasn't reaching the valves and rocker assemblies. I will be disassembling the rocker system components over the weekend and will report back. Regards Bill Chasser jr TD4834 |
| W. A. Chasser Jr |
| Bill, I sympathize. Been there, done that, but it's a hobby, bring your checkbook and aspirin. Have you ever owned a boat? Sounds to me like you need to get an engine in that car pronto so you can enjoy driving it while you're getting this secondary project straightened out - over the winter, on a test stand that isn't a finished drivable car. Divide and conquer. You know... they are a hoot to drive. Building a custom engine, not a hoot. ...... |
| MAndrus |
| Step one is figure out why no oil. At next startup, spin engine over w/o plugs and visually watch for oil coming out from the rockers. Then start. George |
| George Butz |
| Bill, I feel your pain. If the Edney's don't have them, try contacting Manley Ford ( manley776@yahoo.com or call (cell) 734 634 0713) I believe he used to carry them but not sure where they came from...maybe from the Edney's? If worse comes to worse I'm not sure I'll ever use mine - if you exhaust everyone else, let's talk some day. Gene |
| Gene Gillam |
| Bill, Check with http://xpagengineering.co.uk/ as well as B&G. Gene |
| Gene Gillam |
| Unable to find a ready fix for my Laystall it has been shelved for the time being. I retrieved my stock iron head from the shop after having Len's roller springs fitted. A real bad choice in fitting this stock head back on an engine with all the mods I have involved in this project. Bad ports, small valves and a drsctically lower compression ratio. I didn't want to Modify my original Head But I want to try and enjoy this car for a bit this year as my search continues for another Laystall Bill Chasser Jr TD4834 |
| W. A. Chasser Jr |
| Bill, Sounds to me like you're using Castrol 'R; either as a lubricant, or a few drops in the gas for excitement. If so, Castrol 'R' is not a mineral oil, but rather, vegetable based (oil from the caster bean) Its main virtue was that it maintained viscosity at high temps, but if left in an engine too long, would cool and leave a hard varnish on most surfaces. The oil-ways in the cylinder head were particularly vulnerable. That was many years ago. (I still have a few gallons). Today's oils are much more stable and there is no need for vegetable-based racing oil. If I'm wrong, I'd love to know of the source of the varnish. Gord Clark Rockburn, Qué. |
| Gord Clark |
| Bill Sorry I did not read this prior to seeing you tonight. Have an early TD head that has been milled down quite a bit. It has O miles on it since a full rebuild. May be good for a higher compression engine. If you get up the hill, stop in and take a look. 3463 wedge hill placerville ca. |
| Bruce TD4139 Cunha |
| Bruce I was going to take a run up to your place after leaving Lawries this afternoon but became collateral damage with a distracted driver on Hwy 50. Im okay but Sarah (my Aussie got tossed around and shook up pretty badly. Luckily she seems to be okay physically as well. The HHR not so much but it's fixable with light damage. The car that hit me ... demolished after three over corrections, trying to PITT maneuver me, and then slamming into a sound wall. God, once again was watching over this family. Cheers Bill Chasser Jr TD4834 |
| W. A. Chasser Jr |
This thread was discussed between 19/07/2015 and 07/08/2015
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