Hi,
A couple of days ago I changed my Sprints timing chain with a complete kit (including a Jag tensioner) I'd purchased from Robsport.
Before the change the car was running perfectly (but with a noisy chain) and the ignition timing, set with a strobe, was at 10 degrees BTDC.
So after the change, I was driving it home and I noticed that the temperature was reading higher than it usually does and on hills it'd pink, indicating the timing was out. I expected this and the next day when I put the strobe timing light on the thing, it was running at 22-24 degrees BTDC. I reset it to 10 BTDC and today I took it out for a 70kms drive and its still running hotter than it did before the chain change. Its no way near overheating and its performing very well. Its just hotter by about a needle thickness, maybe two.
Any suggestions as to what's going on?
Cheers,
Rob
Timing
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gmsclassics
- TDC Member
- Posts: 670
- Joined: Fri Oct 06, 2006 9:57 am
- Location: Auckland, New Zealand
Re: Timing
I'm not an expert, but if the timing was at 10 before and 22 afterwards then I have a horrible suspicion that the sprockets weren't quite lined up as they should be when you fitted the new chain. I would remove the cam cover and at least double check that the cam sprocket marks are aligned at TDC (plugs out, screwdriver down the front plug touching the piston top, in gear and gently rock the car forwards). I'm not sure what the symptoms would be having the cam slightly out but something is causing it to run hotter.
If it was just the jackshaft out by a tooth or two then you've corrected that. Just having a new chain and tensioner, being tighter could conceivable create more friction and thus run hotter to start with, but I think relying on that as the answer would be clutching at straws.
I would be inclined to do further investigation before running it any more.
It will be interesting to see what thoughts others have.
Geoff
If it was just the jackshaft out by a tooth or two then you've corrected that. Just having a new chain and tensioner, being tighter could conceivable create more friction and thus run hotter to start with, but I think relying on that as the answer would be clutching at straws.
I would be inclined to do further investigation before running it any more.
It will be interesting to see what thoughts others have.
Geoff
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Sundowner
Re: Timing
Thanks for your answer Geoff,
I'm confident that all the points in "the book" were followed to the letter.
However, I do remember that there were some strange looking scratch marks on the jackshaft sprocket, indicating that maybe it was set wrong by a previous mechanic, and we've just corrected it.
I've just been through the book again and re-read it all, step by step and as I mentioned above, I'm confident that it was all done correctly.
Its dark here now but come tomorrow morning, I'll get out there and re-check everything.
Again, thanks for taking the time to answer. Its much appreciated.
Cheers,
Rob
I'm confident that all the points in "the book" were followed to the letter.
However, I do remember that there were some strange looking scratch marks on the jackshaft sprocket, indicating that maybe it was set wrong by a previous mechanic, and we've just corrected it.
I've just been through the book again and re-read it all, step by step and as I mentioned above, I'm confident that it was all done correctly.
Its dark here now but come tomorrow morning, I'll get out there and re-check everything.
Again, thanks for taking the time to answer. Its much appreciated.
Cheers,
Rob
Re: Timing
Rob if you get tdc up and take oil filler cap off camcover you can see the marks on the cam to cam cradle so no need to remover cover. If they are ok then the jackshaft is not important , only the position of the dizzy rotor which you have sorted it seems.
Tony
Tony
Membership 2014047
Re: Timing
Typical symptoms of a too much advanced waterpump.
When a camshaft is timed too early an engine does run slightly hotter but you would notice the engine running different as before.
Jeroen
When a camshaft is timed too early an engine does run slightly hotter but you would notice the engine running different as before.
Jeroen
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com
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Jon Tilson
- Guest contributor
- Posts: 11179
- Joined: Tue Oct 03, 2006 9:45 pm
- Location: Middlesex
Re: Timing
Just so we dont worry those down under I should point out that Jeroen was being humorous about the water pump....
Mind you I suspect down under you have a fair few dutch comedians about....they were with you on the death railway and you needed
a sense of humour to get through that....
Sorry about the historical digression....blame what I was just looking at online and a recent holiday...one of the survivors has just reached 100.
If the pointers all line up after a few rotations it should all be fine and its quite normal for the jackshaft to move a tooth during a t/c change and put the dizzie out a bit. The dizzie slots are about 1 and a half tooths worth so you shoud be able to get it on the timing mark ok.
Jonners
Mind you I suspect down under you have a fair few dutch comedians about....they were with you on the death railway and you needed
a sense of humour to get through that....
Sorry about the historical digression....blame what I was just looking at online and a recent holiday...one of the survivors has just reached 100.
If the pointers all line up after a few rotations it should all be fine and its quite normal for the jackshaft to move a tooth during a t/c change and put the dizzie out a bit. The dizzie slots are about 1 and a half tooths worth so you shoud be able to get it on the timing mark ok.
Jonners
Note from Admin: sadly Jon passed away in February 2018 but his humour and wealth of knowledge will be fondly remembered by all. RIP Jonners.
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Sundowner
Re: Timing
This morning I went over to the shed, and set about investigating the timing settings.
I rocked the car forward until the timing marker on the pulley was indicating 0 degrees, TDC.
Then, as Tony suggested, and with my heart in my mouth, I unscrewed the oil filler cap and checked the marks on the cam. Can you imagine how relieved I was when I found that everything lined up as it should and we don't have to do it all again?
I suppose I'll just have to get used to the NEW "normal" mark for the temperature gauge needle.
Again, thanks for your good advice, ideas and suggestions.
Cheers,
Rob
I rocked the car forward until the timing marker on the pulley was indicating 0 degrees, TDC.
Then, as Tony suggested, and with my heart in my mouth, I unscrewed the oil filler cap and checked the marks on the cam. Can you imagine how relieved I was when I found that everything lined up as it should and we don't have to do it all again?
I suppose I'll just have to get used to the NEW "normal" mark for the temperature gauge needle.
Again, thanks for your good advice, ideas and suggestions.
Cheers,
Rob