Lotus Elan

Disappointing Dyno results

PostPost by: jfornarola » Thu Mar 05, 2020 5:27 pm

I would be curious to know how you broke in the engine? What oil was used (mineral or synthetic). I had racer friend ( '70 BMW 2002 itb) who broke-in his engine with a synthetic. He was down on power by a very significant amount. Between qualifying and the race he changed back to a mineral oil and by the end of the race (20 minutes) he was able to pull me on the straights. As I mentioned it was a very significant increase in power.

I'd also be curious about the header. On my twin cam, during our break-in on the dyno we saw a big difference between the stock manifold and a header sold by Dave Bean - long tube - 4-2-1 to bring out the mid-range. Once we had the engine installed I got about 122 at the rear wheels on an +80 F day at 5200 ft (Denver).

There was a mention of a compression test. I'd suggest going a little further and perform a leak-down test as well. I think around 4% or less is a good target but others here will have some better numbers to target.

Just some ideas.
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PostPost by: ROADRUNNER » Thu Mar 05, 2020 7:10 pm

jfornarola wrote:I would be curious to know how you broke in the engine? What oil was used (mineral or synthetic). I had racer friend ( '70 BMW 2002 itb) who broke-in his engine with a synthetic. He was down on power by a very significant amount. Between qualifying and the race he changed back to a mineral oil and by the end of the race (20 minutes) he was able to pull me on the straights. As I mentioned it was a very significant increase in power.

I'd also be curious about the header. On my twin cam, during our break-in on the dyno we saw a big difference between the stock manifold and a header sold by Dave Bean - long tube - 4-2-1 to bring out the mid-range. Once we had the engine installed I got about 122 at the rear wheels on an +80 F day at 5200 ft (Denver).

There was a mention of a compression test. I'd suggest going a little further and perform a leak-down test as well. I think around 4% or less is a good target but others here will have some better numbers to target.

Just some ideas.



Carefully run in with standard good quality mineral oil - this is just a road car.

It has a TTR manifold.

A leak-down test will form part of the next stage of the investigation !
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PostPost by: collins_dan » Thu Mar 05, 2020 10:00 pm

Question to the group - how do you check cam timing with dial indicator with the engine in the car? I was under the impression there wasn't enough room, so the engine needed to come out. I would really like to have this done on mine for the same issue, but have put off as I don't want to pull engine. Timing marks line up fine, but hp on dyno is off 20% and it just feels less responsive than I remember it. Thanks, Dan
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PostPost by: nmauduit » Thu Mar 05, 2020 11:24 pm

collins_dan wrote:Question to the group - how do you check cam timing with dial indicator with the engine in the car? I was under the impression there wasn't enough room, so the engine needed to come out. I would really like to have this done on mine for the same issue, but have put off as I don't want to pull engine. Timing marks line up fine, but hp on dyno is off 20% and it just feels less responsive than I remember it. Thanks, Dan


I've drilled and tapped a spare crank pulley bolt to attach the dial, which I can read either from the top with a mirror, or through the radiator opening. I also rotate the crank via this bolt (needs a relatively flat wrench, that I extend beyond the disk to get leverage for fine positionning).
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PostPost by: Davidb » Fri Mar 06, 2020 2:36 am

I have done it by gluing an old small timing disc to the front pulley-I cut the centre of the disc out years ago for another car so I have to glue it on with silicone sealant.
Works very well.
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PostPost by: Craven » Fri Mar 06, 2020 2:20 pm

nmauduit wrote:
collins_dan wrote:Question to the group - how do you check cam timing with dial indicator with the engine in the car? I was under the impression there wasn't enough room, so the engine needed to come out. I would really like to have this done on mine for the same issue, but have put off as I don't want to pull engine. Timing marks line up fine, but hp on dyno is off 20% and it just feels less responsive than I remember it. Thanks, Dan


I've drilled and tapped a spare crank pulley bolt to attach the dial, which I can read either from the top with a mirror, or through the radiator opening. I also rotate the crank via this bolt (needs a relatively flat wrench, that I extend beyond the disk to get leverage for fine positionning).

If you can find the correct info for your cams you can use the ‘ Lift at top dead centre ‘ method where the only need is to slowly rotate the engine all checks can be done from above, no need for timing disc’s etc.
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PostPost by: collins_dan » Fri Mar 06, 2020 4:38 pm

Great, thanks for the tips.
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PostPost by: ROADRUNNER » Fri May 01, 2020 8:57 am

I finally seem to have got to the bottom of the mystery of my missing power, after additional significant expense and effort.

The list of faults from the original Myers rebuild is lengthy and depressing. I'm at a loss to understand how the car could have been handed back to me with any degree of confidence, particularly given the size of Neil's bill.

Cam timing way out - cam chain badly worn, adjuster screw all the way in, suggesting this was never replaced. Cam chain quadrant bent and cracked. Leaking and elderly water pump, again supposed to have been replaced during the rebuild.

Front cover oil leaks due to it being badly sealed and fitted - stripped threads in the block securing it, and incorrect bolts fitted between the head and the front cover. As a result, neither the front cover or the sump were ever properly secured.

Elderly oil pump leaking and clearly not replaced.

Poor valve guide clearance, and little indication that any porting had been done whatsoever, despite this being charged for.

All these faults have now been rectified, and a second rebuild will hopefully transform this engine and liberate the missing power. I'm very much looking forward to my first run out in it, and will report back once it has revisited the dyno.
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PostPost by: 661 » Fri May 01, 2020 2:22 pm

It's good to hear that you appear to have light at the end of the tunnel, but without all the information I'm probably slightly wrong to allow my blood to boil at the way you appear to have been treated.
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PostPost by: richardcox_lotus » Fri May 01, 2020 8:34 pm

Sad to hear. Are you planning to go back to the Myers for a partial refund ? It’s always tricky when you’ve had to have someone else take it apart.

Let us know how you got on - hope the rebuild is to your satisfaction.

Regards
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PostPost by: elanfan1 » Fri May 01, 2020 9:41 pm

ROADRUNNER wrote:I finally seem to have got to the bottom of the mystery of my missing power, after additional significant expense and effort.

The list of faults from the original Myers rebuild is lengthy and depressing. I'm at a loss to understand how the car could have been handed back to me with any degree of confidence, particularly given the size of Neil's bill.

Cam timing way out - cam chain badly worn, adjuster screw all the way in, suggesting this was never replaced. Cam chain quadrant bent and cracked. Leaking and elderly water pump, again supposed to have been replaced during the rebuild.

Front cover oil leaks due to it being badly sealed and fitted - stripped threads in the block securing it, and incorrect bolts fitted between the head and the front cover. As a result, neither the front cover or the sump were ever properly secured.

Elderly oil pump leaking and clearly not replaced.

Poor valve guide clearance, and little indication that any porting had been done whatsoever, despite this being charged for.

All these faults have now been rectified, and a second rebuild will hopefully transform this engine and liberate the missing power. I'm very much looking forward to my first run out in it, and will report back once it has revisited the dyno.


You are not the first and won’t be the last.
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PostPost by: mark030358 » Fri May 01, 2020 10:33 pm

If true that is totally $ hit. Fell for you, hope this one is better.
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PostPost by: ROADRUNNER » Sat May 02, 2020 8:50 am

richardcox_lotus wrote:Sad to hear. Are you planning to go back to the Myers for a partial refund ? It’s always tricky when you’ve had to have someone else take it apart.

Let us know how you got on - hope the rebuild is to your satisfaction.

Regards
Richard


Myers dissolved his limited company (Portuni) last year because there were others after him for compensation, but there are other legal recourses available, which I'll be seeking.
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PostPost by: ROADRUNNER » Sat May 02, 2020 8:51 am

elanfan1 wrote:
ROADRUNNER wrote:I finally seem to have got to the bottom of the mystery of my missing power, after additional significant expense and effort.

The list of faults from the original Myers rebuild is lengthy and depressing. I'm at a loss to understand how the car could have been handed back to me with any degree of confidence, particularly given the size of Neil's bill.

Cam timing way out - cam chain badly worn, adjuster screw all the way in, suggesting this was never replaced. Cam chain quadrant bent and cracked. Leaking and elderly water pump, again supposed to have been replaced during the rebuild.

Front cover oil leaks due to it being badly sealed and fitted - stripped threads in the block securing it, and incorrect bolts fitted between the head and the front cover. As a result, neither the front cover or the sump were ever properly secured.

Elderly oil pump leaking and clearly not replaced.

Poor valve guide clearance, and little indication that any porting had been done whatsoever, despite this being charged for.

All these faults have now been rectified, and a second rebuild will hopefully transform this engine and liberate the missing power. I'm very much looking forward to my first run out in it, and will report back once it has revisited the dyno.


You are not the first and won’t be the last.



Specifically relating to Myers ?
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PostPost by: elanfan1 » Sat May 02, 2020 10:33 am

We’ve had discussions already!
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