• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Heavy Tapping low in the Engine

Share this page

Don't wish to teach my grandmother to suck eggs but it is important to realise that bolts and set screws, although similar to look at, were designed with different purposes in mind. Bolts were designed to be used to clamp two or more components (usually with unthreaded holes) and usually with a nut on the end to do the clamping, although not in some cases as they are often used for attaching pulleys where advantage of the unthreaded end is used to give a "dowling" effect. Set screws are used on (usually blind) fully threaded holes and as the thread goes right to the underside of the head the clamping effect is achieved by torquing them up. So try not to use a set screw to clamp unthreaded holes, you might get some slop damaging the hole over time. Well that was the theory anyway.
Grub screws (well our grub screws anyway) do not have heads. They are threaded along their length and can be screwed deep into a threaded hole. They have recesses machined in the end so they can be tightened using an Allen key or small flat head screw driver. You normally find them on instruments.
AJ
ps I disagree with TOC. All that will be left after going thru his list will be the hole that the pistons fit into!
 
6. A professional who hears this noise will know pretty quickly if it is a rod rap or some other problem, so be it Bill​
 
Hi All,

Yesterday we took the car to a local friend who's is a nationally recognized builder of racing engines, as I understand, mostly of which are for LBCs. After a few simple tests, his initial suspect causing the heavy tap was a single crank bearing. However, due to his work load, he would not be able to get to the do a complete issue validation till the end of the month and would pull the pan and bearing caps to identify overall condition of the crank/wear of the bearings.

During our visit, he presented us with the fact that good bearing are very hard to find and good Led incorporated bearings, considered best for racing, impossible. Although his initial diagnosis was that only 1 bearing was at fault, he felt it would be a safe bet that, if caused by wear, all crank bearings should be replaced and the cost for all would not be substantially greater (i.e. a multiple of 6).

At this point, this Healey is parked until time to deliver it to the mechanic at the end of the month.

Ray(64BJ8P1)
 
I took an engine to a race engine builder... once. I knew it was going to be expensive. He also told me it would not be quick because all of his racing clients got priority. I told him I understood. However, at the end of 4 months all he had done was clean and inspect the parts. That cost me $300. Knowing the work was still months away I took the engine in pieces to a regular machine shop. They repeated the measurements and suggested what actions should be taken. Then they did the machining and I did the reassembly myself.
 
If a bearing is gone.....and if the specialist is not suggesting 90 degree crank journal micrometer readings, find someone else.

Once a bearing goes, and it's been driven, chances are high the crank is flat.

Which means engine out, crank out, crank turned.....then have the rod big ends sorted, then check the bores, new rings.....by the time you're done, you may just understand the reason for the suggestion for pulling the engine.

Checking crank journals on your back is no fun.
 
Hi All,

UPDATE
The BJ8 Phase 2 was driven to the garage where another friend and "Positive Earth Drivers Club" member and professionally builds/rebuilds of SBC racing engines initially diagnosed the issue to be connecting rod bearings (as so many of you have done also). After dropping the pan, it was found the #1 connecting rod bearing was shot but had not yet caused any issues with the crank and all crank journals are still in speck. All 6 journal bearings are now scheduled to b replaced with the engine remaining in the car.

After completion of my friends bearing replacement, I will be considering doing the same replacement as I have a tendency to aggressive shift at around 5K RPM and feel this change could be a good preventative action.

Thanks All for your comments and suggestions,
Ray(64BJ8P1)
 
Last edited:
Great! Let us know how things are going and how the engine runs after the new shells are installed.
 
There is always a reason.
There has to be a reason that your #1 rod bearing failed. Is the gallery plugged? Was there an initial torque issue? A defective bearing shell. The list goes on.
IMHO just replacing the bearings may be a temporary fix but knowing why there was a failure is critical for it not to happen a second time.
 
Hi Joe,

Yes, there must be a reason. Since the car was purchased not long ago from the latest owner after sitting for at least a decade, my friend does not know whether the engine had major replacements prior. However, since the engine had good compression, good oil pressure, and pulled hard, this issue seemed to appear from out of the blue and we intend to ask that question of the engine builder to determine what else to expect and prepare for.

This is not a unique issue, however. 2 weeks after accepting delivery of my new BJ8 P1, I also had a bang in the engine and had it towed back to the dealer. It turned out to be a loose connecting rod that allowed the piston to pop up and hit the valves. After disassembly, it turned out to be a loose connecting rod and the piston, bearing and valves were replaced under warranty... so I thought. A number of years and tens of thousands of miles later, I had a leaking head gasket and pulled the head. As it turned out, the piston was never replaced and you could see the valve marks on the piston. That was about 100K miles ago and the same piston is still in place. When changing the gasket, I had the head shaved 0.06" resulting in an increase in compression. This higher very good compression, combined with good oil pressure and general engine operation has stopped me from considering an engine rebuild or stopping my habit of shifting around 5K RPMs.

Although I do believe in preventative maintenance, my father, a non-mechanically astute individual, commonly quoted "If the car runs good, don't lift the Hood", and his family cars were used with little issue for multi-decades. In my case, I have followed this path with respect to the engine and have addressed the issues that have been defined and obvious. Replacing my crank bearings is still a question in my mind as too many seem to have had issues after major work has been completed by trusted mechanics. Why, I don't know but …

Ray(64BJ8P1)
 
And you don't know history. One of the reasons to pull the engine.
Strip it down. Clean out the crank and block oil galleries and ports.
Have the big ends of the rods checked for size and roundness.

It's a new line in the sand. Now you know.

Your buddies cross mic'ed the throw?
You have no idea how badly a thumping bearing can pound a machined surface.

Your car. Your money.
 
TOC,

Yes, you can draw a new line in the sand (or snow at Floe Ice, Antarctica) by knowing the true specifics of your engines condition...especially in a Healey you have recently purchased and had multiple owners. However, there are many issues that have been reported in the Threads of this Forum by those who have taken this approach...and paid for a full rebuild? Additionally, as mentioned by many, the quality of replacement parts has deteriorated over the years and many of the installed parts are far better then those that can be acquired. So, when considering component replacements, I am more apt to addressing only those part replacements that have demonstrated issues.

I do see you point and thank you for making it. I will ask the professional race engine rebuilder if he has cross mic'ed the throw and report his response.

Again thank you for your thoughts as your question demonstrates a level of experience and knowledge in this area that is far greater then I possess and have benefited from.

Ray(64BJ8P1)
 
Last edited:
When I became the custodian of a bj8 over three years ago I was paranoid about a tapping noise and low oil pressure once the engine was up to temperature, firstly pulled all the followers and found three to be badly pitted obviously causing a hammering effect, This rectified the tapping or heavy ticking whatever you want to call it. The rocker bearings were then replaced, still low oil pressure. Oil pan removed lube pump inspected and big end caps removed to my horror found a po had put the caps on the wrong cylinder on two. Shells showed wear with two cylinders just down to the copper stuff plasigauged the crank and got away with it. New shells and she has done several thousand miles now with no issues. I will pull the engine soon as I am sure the mains need inspecting/replacing and this is not possible without a full strip down. But having just brought the car at the time this was an expense that had to wait. I would love to get hold of a spare engine and rebuild it myself from scratch knowing that everything was perfect. But hey ho finding one ......
 
Hi All,

Update:

We drove down to retrieve the Healey BJ8P2 form the engine rebuilder today and learned what the issue was. It seemed that the engine was once before rebuilt in the late 1990s or early 2000s using a good grade of led/copper bearings at the time. This was verified by the bearing manufacturer's mark on the underside of the bearing which was different from those originally installed when manufactured. It turned out that, although 6 bearing would be replaced by the rebuilder, only the # 1 bearing showed excessive signs of ware down to the copper strata and was the cause of the low engine tick. Upon careful examination, all journals were found to be round and in spec and were well cleaned and polished before new journal shells installed. The engine ran responsive with no exhaust smoking on the homebound trip and is scheduled to go back to the rebuilder for a 50 mile oil and filter change. A follow-up phone call was received from the rebuilder checking on conditions experienced during the homebound drive.

Although I consider myself reasonably knowledgeable and familiar with upper engine internals, I have had very little real experience addressing issues in the lower section so my comments are more reflective of the thoughts of others. As I understand, the #1 connecting rod bearing is the last to be oiled as it is furthest from the pump. This condition, combined with cold start oil deprivation, could explain why the #1 connecting rod bearing showed the greatest amount of ware, however, I also understand that a mispositioned or blocked shell oil port can also be a common cause of premature bearing ware on our engines. This condition was not found during the in-car examination and bearing replacement.

The rebuilder suggested considering a change from the original filter system to a spin-on filter adapter sporting a drain-back valve cartridge for quicker cold-start oil distribution. A while back, I believe Randy mentioned a vertically mounted spin-on filter adapter that would be advantageous for oil change pre-filling before mounting. However, I have not been able to find a further reference or an adapter with this configuration and would appreciate any assistance.

Finally, the rebuilder recommended using Amsoil 20W50 synthetic and has found this oil to have sufficient ZDDP for older classic engines and superior viscosity maintaining performance under stress and temperature. Additionally, he suggests eliminating the addition of a led additive to the fuel and brought up the use of Marvel Mystery Oil as a gas additive to eliminate led-induced plug fouling and improve upper seal and ring performance.

Although I appreciate the rebuilder's knowledge and extensive experience to the point of my following his suggestions, I do not have sufficient knowledge to justify his suggestions to others and intend to do further research toward that end. I will continue to provide updates.

Ray(64BJ8P1)
 
Last edited:
AFAIK, there are no 'lead additives' sold today, being that it's illegal and all (note that teta-ethyl lead is EXTREMELY toxic, since it's an organic compound made with a toxic metal that is easily absorbed by animal tissue--that's why it's illegal). All are 'lead substitutes' using sodium or other light metals to (try to) perform one of the jobs lead did (protecting exhaust valve seats). If you don't drive your Healey often and hard I wouldn't worry about it; if you do you really need a 'no lead' head rebuild (pretty much automatic if a shop rebuilds heads). If you don't use leaded gas--avgas is the only fuel remaining that has lead in it--then you cannot possibly have lead plug fouling (it is common in lower compression aircraft piston engines but, of course, they usually use 100LL fuel, when the older 87-octane leaded fuel and even 91-octane autogas would be sufficient). That statement alone makes me question your mechanic's knowledge. I've never heard of Marvel Mystery Oil even claiming to prevent pinging; it's usually recommended as 'top end lubrication,' and I'm not sure that's necessary at all.

Has your mechanic performed the complex chemical analysis necessary to determine how much ZDDP is in Amsoil oil? Some of that info is online, or maybe even on the bottle (bobistheoilguy.com used to have a lot of that, but I haven't visited in a while). There are now quite a few 20W-50 oils on the market claiming 'extra ZDDP;' Hemmings sells it, I saw an ad for Brad Penn 20W-50 that claims 'high levels,' Moss, I believe, sells one and Valvoline 20W-50 claims to have sufficient ZDDP. I put 110K miles on my BJ8's engine using various mineral 20W-50 oils (Castrol at first, Chevron for many years when Costco sold it, then Valvoline for the last few years). We had a little bit of spalling on a couple of the lifters and cam lobes, but nothing major. Note that too much ZDDP is bad, as it can be corrosive to metals--not good--at higher levels. Many of the problems with cams in solid lifter cars can be attributed to improper break-in procedure, I believe.

Frankly, I think your mechanic should stick to machining and assembly, and leave the chemistry to, well, the people that know something about it.
 
Bob,

Frankly, I find the engine rebuilder's experienced perspective to have more credibility then the limited views of others. So what is your problem? If you don't like his suggestions, don't follow them.

We have discussed ZDDP in oils as something to look for when selecting an oil for your Healeys. I happen to prefer Mobil1 15W50 which promotes its containing ZDDP on the container as a benefit for Classic engines. If its ZDDP content was not sufficient to provide the added classic engine protection promoted, I would say it was falsely advertised. Since Amsoil 20W50 also indicates it contained ZDDP, I would expect it to be in sufficient quantity to provide the desired protection to a classic engine.

There are a number of lead substitute additives and even one called ReLead that is chemically supposed to provide the lead benefits eliminated from our fuels. Some, if not all, of these additives seem to deposit an orange colored film on the plugs that seem to have caused plug fouling. His suggestion is that you do not need these additives and he uses and suggest the
Marvel Mystery Oil as being a better fuel additive alternative.

Keep in mind that he builds and rebuild engines meant for the stresses incurred during racing. These engines are often torn down and rebuild every season and show the result of heat and stress not experienced by our engines over decades of common use. As a result, his perspectives and conclusions have been drawn from a high number of actual experiences that show practical results.

Bob, I appreciate your perspective and often value it. However, this time I frankly do not appreciate the manor in your response.
Ray(64BJ8P1)



​
 
Last edited:
Ray,

My response was based solely on his (reported) comment that "Additionally, he suggests eliminating the addition of a led additive to the fuel and brought up the use of Marvel Mystery Oil as a gas additive to eliminate led-induced plug fouling and improve upper seal and ring performance."

Unless you're using leaded fuel--avgas, or I suppose some of the race fuels may still have it--there is no way you will get lead fouling of the plugs--none of the 'alternates' or 'substitutes' have it--hence my skepticism.

Bob
 
Joe Schlosser said:
There is always a reason.
There has to be a reason that your #1 rod bearing failed. Is the gallery plugged? Was there an initial torque issue? A defective bearing shell. The list goes on.
IMHO just replacing the bearings may be a temporary fix but knowing why there was a failure is critical for it not to happen a second time.
Click to expand...

I just remembered going through a bearing selection process when I had the engine in my BJ8 rebuilt. I had bought 0.020" over crankshaft bearings a long time ago when somebody on a forum or list had them for sale, and I assumed my crank would need turning, but not more than 0.020 (if they needed 0.010 turning I figured I could just go ahead and do 0.020, not knowing that turning more than absolutely necessary may not be a good idea--I'm still learning). Anyway, the crank mic'd fine and did not need any work--except polishing, maybe, but I don't know if that was done--at nearly 200K not-easy miles! So, I offered up the 0.020 bearings from a highly-respected brand--someone here or on the mailing list snatched them up immediately, and I think I took a loss on them--and bought STD bearings from one of the 'usual suspects.' After that I heard--IIRC from the guy who bought the 0.020s that the brand I'd bought might be suspect (I think they were Vanderwall (sp?), which at one time, at least, was quality and possibly OEM; my fear is that they might be re-branded County brand).

In a nutshell, it sounds like it might have been a defective bearing. I'm not aware of any issues where some bearings get starved in the Austin engine, but of course a bearing could be installed with its oil channel misaligned or other mistake. My engine builder, who I felt was competent and extremely meticulous told me my bearings looked OK, but one did have a slightly different coloring from the others. He felt it was likely a batch-to-batch variance, but that gives me cause for concern (does not give the 'warm and fuzzies' WRT QA processes). The engine now has about 10K miles of mostly highway miles, good oil analysis and no other potential issues (so far).
 
Back
Top