jamesmartin
Well-Known Member
presumably by zeroing you mean setting it near the piston and gently pulling the needle up then allowing it to drop, then twisting dti over to the piston then turning crank till tdc is achieved at the 4 quarters
neilly
Well-Known Member
That is the way I would do it. For each piston. Except it is not a DTI...................
..I know I am being pedantic.Cheers
jamesmartin
Well-Known Member
yes you areThat is the way I would do it. For each piston. Except it is not a DTI...................
Cheers
perhaps not but its the generic name used in any build shop ive been in
neilly
Well-Known Member
yes you are
Sorry, could not help it, A Dial Indicator is what is being used , not a Dial Test Indicator.......
As you say tho, it appears to have become a commonly used name for some reason.
Cheers
Not so much worried, mate. Obviously, I don't want to get it wrong but want to learn from this and hopefully get it as close to right as possible. Call it youthful curiosityIf your that worried Al stick a 0 hole gasket on !
No worries , neilly and if I'm doing something daft I'd rather you said. That was more me referring to my inexperience and knowing I could well be doing something wrong. If I thought you were being unreasonable I would politely tell you
Yes, James that what I was doing last night.
Second set of measurements and I obviously got something wrong with No3 last night.
I've used two methods tonight.
Zero'd on a spirit level like this to get a generic reading across the piston surface, as I think raywin was suggesting.
Then I did one reference to the head and took a reading either side of the piston hole (timing end & clutch end) like this.
This is what I got
Piston 1 Piston 2 Piston 3 Piston 4
spirit level 0.65 0.67 0.69 0.68
two readings 0.61 0.62 0.68 0.72 0.67 0.77 0.71 0.63
Don't know how I got those readings for piston 3 last night other than my back was aching from being bent over cleaning the big end bolt threads and nuts and it was late!
That's in to the three hole range, with a bit to spare on the three hole gasket. However, the stand down on the valves were slightly over tolerance (I'll have to go back and check exactly) So, the three hole should be just about right.
jamesmartin
Well-Known Member
its the highest point your looking due to contact not an averageNot so much worried, mate. Obviously, I don't want to get it wrong but want to learn from this and hopefully get it as close to right as possible. Call it youthful curiosity
No worries , neilly and if I'm doing something daft I'd rather you said. That was more me referring to my inexperience and knowing I could well be doing something wrong. If I thought you were being unreasonable I would politely tell you
Yes, James that what I was doing last night.
Second set of measurements and I obviously got something wrong with No3 last night.
I've used two methods tonight.
Zero'd on a spirit level like this to get a generic reading across the piston surface, as I think raywin was suggesting.
View attachment 122307
Then I did one reference to the head and took a reading either side of the piston hole (timing end & clutch end) like this.
View attachment 122308
This is what I got
Piston 1 Piston 2 Piston 3 Piston 4
spirit level 0.65 0.67 0.69 0.68
two readings 0.61 0.62 0.68 0.72 0.67 0.77 0.71 0.63
Don't know how I got those readings for piston 3 last night other than my back was aching from being bent over cleaning the big end bolt threads and nuts and it was late!
That's in to the three hole range, with a bit to spare on the three hole gasket. However, the stand down on the valves were slightly over tolerance (I'll have to go back and check exactly) So, the three hole should be just about right.
neilly
Well-Known Member
If you do get spurious readings, especially of such a thickness difference, then as said before, using a set of feeler gauges or the old mark one eyeball. Can help you keep your sanity.
Cheers
_______________________Piston 1________________ Piston 2___________ Piston 3___________ Piston 4
spirit level ________________0.65___________________0.67______________ 0.69______________ 0.68
two readings __________0.61 ____0.62__________ 0.68____ 0.72 _______0.67___ 0.77 _______0.71___ 0.63
I'd set the readings out per piston, with the space bar. The website took the spaces out So I've done it again with underscores. Edit that ya b@*****
Exhaust valve reading was 034 which is 002 over spec. That converts to 0.05mm If I take 0.77 (from above readings) as highest upstand and add the two I get 0.82mm which takes me in to a zero hole gasket.
I'll recheck the exhaust valve clearances on Saturday morning. (It's red wine Friday tomorrow night) just to be sure. I'll recheck that piston, probably all of them. It's such fine margins.
spirit level ________________0.65___________________0.67______________ 0.69______________ 0.68
two readings __________0.61 ____0.62__________ 0.68____ 0.72 _______0.67___ 0.77 _______0.71___ 0.63
I'd set the readings out per piston, with the space bar. The website took the spaces out
So I've done it again with underscores. Edit that ya b@*****Absolutely, JM. I've just found the valve stand down measurements anorl. Worse than I thought when I convert them to mm.
Exhaust valve reading was 034 which is 002 over spec. That converts to 0.05mm If I take 0.77 (from above readings) as highest upstand and add the two I get 0.82mm which takes me in to a zero hole gasket. I'll recheck the exhaust valve clearances on Saturday morning. (It's red wine Friday tomorrow night) just to be sure. I'll recheck that piston, probably all of them. It's such fine margins.
jamesmartin
Well-Known Member
if so a no hole gasket is the correct choice, and you can take satisfaction that youve checked rather than guessed_______________________Piston 1________________ Piston 2___________ Piston 3___________ Piston 4
spirit level ________________0.65___________________0.67______________ 0.69______________ 0.68
two readings __________0.61 ____0.62__________ 0.68____ 0.72 _______0.67___ 0.77 _______0.71___ 0.63
I'd set the readings out per piston, with the space bar. The website took the spaces out
Absolutely, JM. I've just found the valve stand down measurements anorl. Worse than I thought when I convert them to mm.
I'll recheck the exhaust valve clearances on Saturday morning. (It's red wine Friday tomorrow night) just to be sure. I'll recheck that piston, probably all of them. It's such fine margins.
Hypothetical question, James.if so a no hole gasket is the correct choice, and you can take satisfaction that youve checked rather than guessed
I've read a lot of threads on different forums, where people have taken their heads off for various reasons, and put it back with a no hole just for ease really.
If the piston readings were such that a one hole gasket would have been perfect and you put a no hole in, do you think there would be a noticeable drop in performance due to a loss of compression? Or a theoretical drop that you couldn't tell? Or what?
jamesmartin
Well-Known Member
you can fit a too thick a gasket and probably not notice much difference unless you put it on a dyno or really cold mornings etc ,but you are reducing compression and go out of spec
Cheers. All this does get you thinking.
Yeah, me too. Suppose you could work out the difference in volume and then the compression ratio and compare that to the specified compression ration and see what % difference there is. No idea if that would have any relation to % change in power.
Hmmm, low end power. There's another factor
I'm hoping that at 180K mine was starting to show it's age in terms of performance. So, I'll hopefully notice a bit of an improvement when this one gets going again.
raywin
Well-Known Member
Sorry I was out of office last night (thirsty Thursday) I was worried about my description but you have it bang on and the readings now look pretty good, only 1.5 thou (inch) variaton between them. As James says you are looking for the highest piston so that you can choose a gasket which will keep the clearance between the piston and the valves and avoid a nasty bump.
Measuring like this avoids the possibility of a slip between reading on the block and reading on the piston.
Now you can go forward with more confidence.
Measuring like this avoids the possibility of a slip between reading on the block and reading on the piston.
Now you can go forward with more confidence.
Cheers, raywin. Great idea and another method to check average heights. Excellent! Looks like I'm buying another gasket tomorrow, which is no bother. I will double check measurements tomorrow thought.
We've git a Citroen C3 and a suspension spring has snapped, so that's priority job tomorrow. :-(
We've git a Citroen C3 and a suspension spring has snapped, so that's priority job tomorrow. :-(
raywin
Well-Known Member
Once again the dastardly French cause problems.
Ha, ha. Tbh we've had a C1 for 6 years as a 'pool' car, since the eldest lad past his test. All three are now driving and the C1's have been awesome. Not a jot of bother, cheap as chips, air con, electric windows, ABS, electric windows, not enough power to pull your hat off! Perfect for teenage lads.
Got the C3 two weeks ago, 09 plate with only 30k on the clock. This morning bottom coil of the rear, nearside spring was lying on the drive. Picked the springs up tonight on way home, so early start on them tomorrow. Engine after that.
Ok lads, another basic question. Gaskets! I've got a lot to fit from the top and bottom gasket sets.
Head gasket, manual says, block and head surfaces cleaned, gasket in dry. Other gaskets get a smear of clean oil. Of the ones I've got coming up, which ones get what treatment?
Head gasket, manual says, block and head surfaces cleaned, gasket in dry. Other gaskets get a smear of clean oil. Of the ones I've got coming up, which ones get what treatment?
jamesmartin
Well-Known Member
head gasket is dry , the others benefit from some blue hylomar to hold in place only a little as they will spread and split if wet or oiledOk lads, another basic question. Gaskets! I've got a lot to fit from the top and bottom gasket sets.
Head gasket, manual says, block and head surfaces cleaned, gasket in dry. Other gaskets get a smear of clean oil. Of the ones I've got coming up, which ones get what treatment?
