What should I do differently?
Discussion
Hi,
My Midget 1500 (Triumph) engine was professionally rebuilt at a very good rate (ie no returns) by a Triumph specialist. He rebuilt it to the same spec as always except it was balanced - which should help bearing life. I used correct grade Penrite Oil and a Fram filter.
For various last minute reasons I only had a few evenings to run it in before its first event - a road rally. I did drive it gently for about 400 miles before the first time I used it in anger. It was driven hard for about 8 minutes in total and another 200 miles fairly gently. On the way home it started to develop a big-end knock and the big end I checked has marked-up. I've ordered a set of top quality, heavy duty, big end shells and mains (which I had asked the first guy to do but he didn't as his normal ones never fail) and my man is fiting them as we speak but it won't be ready till tommorow (Wednesday). I could add maybe 100 miles per night from then on.
I'm supposed to be competing on a rally this Saturday and then at something every weekend for the next few weeks. I havn't got the time, money or patience to go through a failure again so I'm thinking of cancelling Saturday and doing more running in. Alternatively, I could do the rally and go slowly on the tests.
What should I do?
My Midget 1500 (Triumph) engine was professionally rebuilt at a very good rate (ie no returns) by a Triumph specialist. He rebuilt it to the same spec as always except it was balanced - which should help bearing life. I used correct grade Penrite Oil and a Fram filter.
For various last minute reasons I only had a few evenings to run it in before its first event - a road rally. I did drive it gently for about 400 miles before the first time I used it in anger. It was driven hard for about 8 minutes in total and another 200 miles fairly gently. On the way home it started to develop a big-end knock and the big end I checked has marked-up. I've ordered a set of top quality, heavy duty, big end shells and mains (which I had asked the first guy to do but he didn't as his normal ones never fail) and my man is fiting them as we speak but it won't be ready till tommorow (Wednesday). I could add maybe 100 miles per night from then on.
I'm supposed to be competing on a rally this Saturday and then at something every weekend for the next few weeks. I havn't got the time, money or patience to go through a failure again so I'm thinking of cancelling Saturday and doing more running in. Alternatively, I could do the rally and go slowly on the tests.
What should I do?
I think I would want to know why the big ends have failed in such a new engine before running it at full chat again? What did the engine builder recommend as a running in period and what oil did they say to use and have you checked the oil pressure with engine warm? If you have just re-built the bottom end of the engine I would cancel the event and make sure the engine is sound and has a good chance to run at light loads without overheating. After a few hundred miles re-torque the cylinder head and replace the oil. The gradually build up the revs and be aware of any untoward noises as well as coolant temp and oil pressure before running at full revs otherwise you maybe doing this job again soon!!
If it was me, I'd do the event, drive steadily but cleanly round the tests and make sure the regularities are right.
It's the East Anglian I'm guessing??. I've not done that one to be fair but most HRCR rounds are heavily regularity based and as long as you have no wrong tests you won't drop much more than 10 seconds a test. One navigation error on a regularity would drop you more than that.
From memory a lot of crews went very very wrong on private land regularity tests on Airfields last year, get those right and you could get a good result.
It's the East Anglian I'm guessing??. I've not done that one to be fair but most HRCR rounds are heavily regularity based and as long as you have no wrong tests you won't drop much more than 10 seconds a test. One navigation error on a regularity would drop you more than that.
From memory a lot of crews went very very wrong on private land regularity tests on Airfields last year, get those right and you could get a good result.
Running in the engine gently just allows things to bed in and throw up any problems that can be sorted before you work the engine hard. Also re-torqueing CH bolts makes sense to keeep the engine working efficiently and prevents CH gasket failure and I think most manufacturers recommend this. Changing the engine oil after a few hundred miles helps to get rid of any engine assembly lubricant and excess gasket material that can contaminate the oil. I am no expert and agree that the lack of running in may not have affected the big ends but with an oil pressure at constant 40psi then something is amiss and should be looked into before running the engine at all. If the oil pump is new then check the relief valve is the correct one. I think you can alter these by changing the spring but seek proper advice first.
Jefftav said:
I think I would want to know why the big ends have failed in such a new engine before running it at full chat again? What did the engine builder recommend as a running in period and what oil did they say to use and have you checked the oil pressure with engine warm? If you have just re-built the bottom end of the engine I would cancel the event and make sure the engine is sound and has a good chance to run at light loads without overheating. After a few hundred miles re-torque the cylinder head and replace the oil. The gradually build up the revs and be aware of any untoward noises as well as coolant temp and oil pressure before running at full revs otherwise you maybe doing this job again soon!!
Agreed, I would think something is wrong with the initial build. When these cars were new, some people ran them in, some did not and they didn't knock their ends out in the first 1000 miles. Back in the '60's/'70's the OEM where I worked would often run engines at full chat on the test bench with minimal running in, they survived although their longevity would be compromised.Gassing Station | Classic Cars and Yesterday's Heroes | Top of Page | What's New | My Stuff