DRD Posted October 18, 2018 Report Share Posted October 18, 2018 (edited) Hi All, Before I proceed with a costly engine rebuild i would appreciate any advice on this. I have a newly refurbed head and excellent compression test readings, 200psi across all cylinders. However in a leak down test I'm loosing pressure, approx 20% on average. The engine does consume rather a lot of oil so there is an issue but not sure where. Also the hot oil pressure is reasonable, 25psi at idle and 60ish at 2000rpm. The engine doesn't overheat and the oil looks fine. Is it due to bore wear? Any ideas as I can't understand the contradicting pressure tests. Cheers Daz Edited October 18, 2018 by DRD Quote Link to post Share on other sites
Motorsport Mickey Posted October 18, 2018 Report Share Posted October 18, 2018 How long for the leak down test to lose the 20% ? and give us a clue, what are you using for carburation ? Webers or other carbs or PI ? Also have you tried a wet compression test and then a leak down ? Mick Richards Quote Link to post Share on other sites
DRD Posted October 18, 2018 Author Report Share Posted October 18, 2018 I'm running on SU's. Haven't tried a wet test yet. Quote Link to post Share on other sites
DaveN Posted October 18, 2018 Report Share Posted October 18, 2018 What sort of mileage has it got under its belt? Quote Link to post Share on other sites
DRD Posted October 18, 2018 Author Report Share Posted October 18, 2018 Only 35k! Its only done 10k in the last 23 years. Quote Link to post Share on other sites
DaveN Posted October 18, 2018 Report Share Posted October 18, 2018 Could the bores be glazed? When I got mine it had done 58k and did consume oil but after ragging it around the oil consumption improved and it hardly uses any now! Quote Link to post Share on other sites
Motorsport Mickey Posted October 18, 2018 Report Share Posted October 18, 2018 (edited) 1 hour ago, DRD said: I'm running on SU's. Haven't tried a wet test yet. Are you carrying out the test correctly with the pistons fully lifted ? your next test should be a wet one, obviously if the compression increase and the leak down test is vastly improved it points to a piston ring and bore problem. At 400 + miles per annum the engine isn't working, it could well be glazed bores, try some BMEP* running and try to break any glaze without stripping the engine. *Brake Mean Effective pressure Google it. Mick Richards OOpps quick draw McGraw Dave beat me to the post. Edited October 18, 2018 by Motorsport Mickey Quote Link to post Share on other sites
DRD Posted October 18, 2018 Author Report Share Posted October 18, 2018 55 minutes ago, Motorsport Mickey said: Are you carrying out the test correctly with the pistons fully lifted ? your next test should be a wet one, obviously if the compression increase and the leak down test is vastly improved it points to a piston ring and bore problem. At 400 + miles per annum the engine isn't working, it could well be glazed bores, try some BMEP* running and try to break any glaze without stripping the engine. *Brake Mean Effective pressure Google it. Mick Richards OOpps quick draw McGraw Dave beat me to the post. Hi Mick & Dave, I did wonder about glazed bores due to so little use and have tried some Bmep type running. Would that give these symptoms? Daz Quote Link to post Share on other sites
john.r.davies Posted October 18, 2018 Report Share Posted October 18, 2018 If I may, Mickey? The 'Oil Test' will always increase compression. It's if it doesn't that it indicates valve leak. JOhn Quote Link to post Share on other sites
Mike C Posted October 18, 2018 Report Share Posted October 18, 2018 Didn't by chance take any photo's of the bores when you replaced the head? Quote Link to post Share on other sites
Motorsport Mickey Posted October 19, 2018 Report Share Posted October 19, 2018 (edited) 2 hours ago, john.r.davies said: If I may, Mickey? The 'Oil Test' will always increase compression. It's if it doesn't that it indicates valve leak. JOhn Hi John yes correct, but I was suggesting the leak down test dry to wet, may show a difference in rate of loss which if large would encourage me to believe that the engine is losing it through loss of piston ring radial loading and sealing ie glazed bores. (clutching at straws). Daz, lots depend upon what condition the engine was in when the head work was done. I presume you haven't had the car for these last 10 years ? You said the head has been refurbed so with new valves cut in and new guides ? and maybe even skimmed so it would be unusual for the guides or valves to be the cause. Did you remove any/all pistons and glaze bust the bores (maybe not from your comments) or did you remove just one piston and measure bore and piston to confirm wear and ring condition ? The BMEP running needs doing on a gradient (motorway gradients are good for this, long and gentle) to load the engine, top gear and then 500 revs below max torque full throttle down to the floor and hold it there and when you are 2 0r 300 revs over max torque (standard camshaft approx. 3500 revs ?) brake the speed down to the same as before and do it again, and again, and again. You'll probably get 2 or maybe 3 loadings on a gradient then come off at the junction and go back the other way and do again (gradient normally on both sides of motorway). Remember you are removing microns with the piston rings so it will take some time to expand the rings enough to scour the bores and bed in the rings and if you have synthetic oil in probably not even then (very bad for bedding items, too slippy). If I was doing this I'd try and do it every day for maybe 30-40 minutes (listen to the radio) and not expect measurable results until about a month has gone by. Alternatively pay your local rolling road to put it on the rollers and run it on there with the engine loaded down and bed the rings much easier taking maybe an hour. Mick Richards Edited October 19, 2018 by Motorsport Mickey Quote Link to post Share on other sites
DRD Posted October 19, 2018 Author Report Share Posted October 19, 2018 11 hours ago, Mike C said: Didn't by chance take any photo's of the bores when you replaced the head? Unfortunately no Mike, but I think they looked OK then. Daz Quote Link to post Share on other sites
DRD Posted October 19, 2018 Author Report Share Posted October 19, 2018 9 hours ago, Motorsport Mickey said: Hi John yes correct, but I was suggesting the leak down test dry to wet, may show a difference in rate of loss which if large would encourage me to believe that the engine is losing it through loss of piston ring radial loading and sealing ie glazed bores. (clutching at straws). Daz, lots depend upon what condition the engine was in when the head work was done. I presume you haven't had the car for these last 10 years ? You said the head has been refurbed so with new valves cut in and new guides ? and maybe even skimmed so it would be unusual for the guides or valves to be the cause. Did you remove any/all pistons and glaze bust the bores (maybe not from your comments) or did you remove just one piston and measure bore and piston to confirm wear and ring condition ? The BMEP running needs doing on a gradient (motorway gradients are good for this, long and gentle) to load the engine, top gear and then 500 revs below max torque full throttle down to the floor and hold it there and when you are 2 0r 300 revs over max torque (standard camshaft approx. 3500 revs ?) brake the speed down to the same as before and do it again, and again, and again. You'll probably get 2 or maybe 3 loadings on a gradient then come off at the junction and go back the other way and do again (gradient normally on both sides of motorway). Remember you are removing microns with the piston rings so it will take some time to expand the rings enough to scour the bores and bed in the rings and if you have synthetic oil in probably not even then (very bad for bedding items, too slippy). If I was doing this I'd try and do it every day for maybe 30-40 minutes (listen to the radio) and not expect measurable results until about a month has gone by. Alternatively pay your local rolling road to put it on the rollers and run it on there with the engine loaded down and bed the rings much easier taking maybe an hour. Mick Richards Mick - no I've had the car for the past 4 years. I have the complete history from 1990, but not earlier, so the car could have done 124k or 24k if the mileage reading is to believed. I've not had the pistons out but they looked OK last year. My local garage - who did the leak test - said it was bore wear not the rings. Cheers Daz Quote Link to post Share on other sites
Motorsport Mickey Posted October 19, 2018 Report Share Posted October 19, 2018 "My local garage - who did the leak test - said it was bore wear not the rings" How can you tell without measuring the bore ? I can't. 200 PSI on all cylinders doesn't sound like a bad fit between bore and piston ring, my money still on glazed bores (and burnished rings). If driven like a sports car with reasonable revs 4500/5000 it doesn't push out the rings enough to bed them into the bores (it's not revs it needs but the engine loading at max torque) without you carry out specific driving as per BMEP etc, and at an average of 400 miles a year it's not had enough use for you to devote time to bedding them. What oil are you using ? Mick Richards Quote Link to post Share on other sites
DRD Posted October 19, 2018 Author Report Share Posted October 19, 2018 15 minutes ago, Motorsport Mickey said: "My local garage - who did the leak test - said it was bore wear not the rings" How can you tell without measuring the bore ? I can't. 200 PSI on all cylinders doesn't sound like a bad fit between bore and piston ring, my money still on glazed bores (and burnished rings). If driven like a sports car with reasonable revs 4500/5000 it doesn't push out the rings enough to bed them into the bores (it's not revs it needs but the engine loading at max torque) without you carry out specific driving as per BMEP etc, and at an average of 400 miles a year it's not had enough use for you to devote time to bedding them. What oil are you using ? Mick Richards Thanks Mick you're confirming my thoughts. I will do a wet test but I suspect I won't see much difference, I didn't hot to cold. Currently using Valvoline VR1 20W/50, but it probably does need an oil change now. Daz Quote Link to post Share on other sites
Motorsport Mickey Posted October 19, 2018 Report Share Posted October 19, 2018 VR1 20W/50... if it's the mineral oil it should be ok, but if it's the synthetic it won't help your bedding in of rings, it's very slippy. . If you are changing it I would put a flushing oil in to try and remove as much as you can and then your choice of oil, given that you are trying to remove old oil and can stand a little wear when only doing 400 miles per annum I'd fit one of the well known ones, Halfords or Comma (effectively the same oil I believe). It has about 700 ppm Zinc as ZDDP in it but importantly it's well priced so you can change it again if needed to get you onto a mineral oil base. When and if the engine beds in ok with rings to bores and glazing is removed you could go use whatever oil you wish, your choice. Me I use Classic Oils Heritage range, it's 20-50, it's a mineral oil and shows the correct ZDDP range even printing it on the plastic container. Mick Richards Quote Link to post Share on other sites
Richard71 Posted October 19, 2018 Report Share Posted October 19, 2018 48 minutes ago, Motorsport Mickey said: VR1 20W/50... if it's the mineral oil it should be ok, but if it's the synthetic it won't help your bedding in of rings, it's very slippy. . Interesting & concerning, that's what I have in my engine right now. The packaging doesn't say either way if it's mineral or synthetic, I assume(d) mineral? Richard. Quote Link to post Share on other sites
Richard71 Posted October 19, 2018 Report Share Posted October 19, 2018 Seems it's "non-synthetic", see bottom of this page...………………...https://www.valvoline.com/about-us/faq/racing-oil-faq Quote Link to post Share on other sites
Motorsport Mickey Posted October 19, 2018 Report Share Posted October 19, 2018 (edited) Richard, It's worse than you think, as I understand it that spec oil is for the US and is NOT available in Europe. I would check very carefully what you have (or think you have). Is Valvoline vr1 Racing Oil synthetic? Valvoline's advanced synthetic, Valvoline® Racing Synthetic (VR1) Motor Oil, is easily distinguished by its sapphire blue color, but the real difference is the track-proven, high zinc additive package engineered to increase horsepower and provide extreme wear protection. Mick Richards Edited October 19, 2018 by Motorsport Mickey Quote Link to post Share on other sites
Motorsport Mickey Posted October 19, 2018 Report Share Posted October 19, 2018 (edited) 22 minutes ago, Motorsport Mickey said: Richard, It's worse than you think, as I understand it that spec oil is for the US and is NOT available in Europe. I would check very carefully what you have (or think you have). Is Valvoline vr1 Racing Oil synthetic? Valvoline's advanced synthetic, Valvoline® Racing Synthetic (VR1) Motor Oil, is easily distinguished by its sapphire blue color, but the real difference is the track-proven, high zinc additive package engineered to increase horsepower and provide extreme wear protection. Mick Richards Richard, Just done a swift search on it, and this is what I THINK you need. https://www.opieoils.co.uk/p-73741-valvoline-vr1-racing-20w-50-highly-refined-mineral-engine-oil.aspx SCRATCH THIS, JUST FOUND THE SPEC AND IT'S API RATHER THAN ZDDP RATED. Is there ANY possible reason why oil companies can't CLEARLY state what the ZDDP is on the specs ? what possible advantage could be in woolly specs which hint at but don't say the oil is to the ZDDP spec required ? I wonder. Mick Richards Edited October 19, 2018 by Motorsport Mickey Quote Link to post Share on other sites
DRD Posted October 20, 2018 Author Report Share Posted October 20, 2018 11 hours ago, Motorsport Mickey said: Richard, Just done a swift search on it, and this is what I THINK you need. https://www.opieoils.co.uk/p-73741-valvoline-vr1-racing-20w-50-highly-refined-mineral-engine-oil.aspx SCRATCH THIS, JUST FOUND THE SPEC AND IT'S API RATHER THAN ZDDP RATED. Is there ANY possible reason why oil companies can't CLEARLY state what the ZDDP is on the specs ? what possible advantage could be in woolly specs which hint at but don't say the oil is to the ZDDP spec required ? I wonder. Mick Richards I thought this had the right levels of ZDDP, 1200ppm from what I can remember. Are you saying this is not the case. Daz Quote Link to post Share on other sites
Motorsport Mickey Posted October 20, 2018 Report Share Posted October 20, 2018 Daz, I can't tell. If you open the advert up it says Extreme wear protection Strong oil film in combination with specialized additives provide high resistance against extreme pressure and high operating temperatures. Break down resistance High thermal and oxidation stability resists oil breakdown and even the Specification description Specifications: Specifications API SL Ford M2C-153E ACEA A3/B4 GM 6094M I can't find what these specifications define as being the Zinc portion of ZDDP which is why I asked the question why do the oil companies NOT make this important information freely available when you buy the product. Instead you'll find claims that it is "optimised" for ZDDP but not stating it, well that's the equivalent of a family member patting you on the back and saying don't worry we've taken care of all the nasty stuff, comforting but not ultimately provable. If you search the TR forum under ZDDP you'll find dozens of different viewpoints on whether it's required or not and what levels are optimum. What I would say is I would not be running my TR engine on synthetic, but that's my choice, an individual one which we all have to make. Sorting your engine out, comes to in car strip head off and pull a piston and measure piston to bore clearance, if within limits (about 3 thou) for long term road use (can go up to 4 thou for competition ) just rering the pistons, hone all the cylinder bores to remove glazing and refit back together. Then carry out BMEP running to bed the rings, (a good few times) and continue using the car. Avoid 50mpg cruising (I've just had my hair done !) restrictions and make sure there are top gear full accelerations using the maximum torque range carried out on an ongoing basis. OR Just carry out serious BMEP running once a day for a month as itemised and see if there is a reduction in oil consumption, don't be surprised if there's a fair amount of smoke pushed out during the running as oil is scrapped off and burnt. Mick Richards Quote Link to post Share on other sites
Richard71 Posted October 20, 2018 Report Share Posted October 20, 2018 2 hours ago, DRD said: I thought this had the right levels of ZDDP, 1200ppm from what I can remember. Are you saying this is not the case. Daz Hi Daz, If you click on the link I posted earlier to Valvoline's FAQ page, it states .1300ppm Zinc & 1200ppm Phosphorous (they show these figures as a percentage). Hope that helps. I agree with Mick, why is it so difficult for these manufacturers to clearly state the amount of ZDDP present on the packaging, it would save us the trouble of researching a particular product. Richard. Quote Link to post Share on other sites
DRD Posted October 20, 2018 Author Report Share Posted October 20, 2018 On 18 October 2018 at 7:48 PM, Motorsport Mickey said: How long for the leak down test to lose the 20% ? and give us a clue, what are you using for carburation ? Webers or other carbs or PI ? Also have you tried a wet compression test and then a leak down ? Mick Richards Mick, I've just done another compression test on a hot engine both dry and wet. Apart from no. 4 which was 150psi dry and 155psi wet, all the other cylinders were around 195psi dry and 203psi wet. Also the engine seems to be using a bit of coolant as I've had to top up the bottle 200ml. I'm wondering whether it's a head gasket problem for no. 4 cylinder. Daz Quote Link to post Share on other sites
Peter Cobbold Posted October 20, 2018 Report Share Posted October 20, 2018 1 hour ago, Richard71 said: Hi Daz, If you click on the link I posted earlier to Valvoline's FAQ page, it states .1300ppm Zinc & 1200ppm Phosphorous (they show these figures as a percentage). Hope that helps. I agree with Mick, why is it so difficult for these manufacturers to clearly state the amount of ZDDP present on the packaging, it would save us the trouble of researching a particular product. Richard. That is the correct units for describing the level of ZDDP. "1300ppm ZDDP" is about 7-fold lower level. There's a long thread a year or so ago where we uncovered many classic oils using what is, to me, sheer trickery. As a rule of thumb if an oil is catalyst-friendly it has a much lower ZDDP concentration that the oils our TR engines were designed to use.. Peter Quote Link to post Share on other sites
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