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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 24 Jan 2022 : 21:49:36
| What does the collective think of these bore surfaces. There is a very small perceptible lip at the top. No vertical scratch marks in any of the bores.
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | Edited by - andydeans3 on 24 Jan 2022 21:50:15 |
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SAAB96L V4 Mad
United Kingdom 501 Posts | Posted - 25 Jan 2022 : 09:00:22
| Good Morning, Andy.
As far as a bore goes its knackered !! However, it will run and work but nowhere near its optimum, plus it will probably use oil. Depends what you want from the engine.
Sorry to be the bearer of such news.
Regards.
Richard. | |
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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 25 Jan 2022 : 11:45:30
| Richard Thanks for the info. It's not my engine, it's the engine of another 96er, in the county, that I'm helping out. Why exactly do you think it's knackered? The black ring at the top, though there is not a big step there, or the blotchy marks further down the bore.
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | |
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Derek V4 Guru
United Kingdom 2187 Posts | Posted - 25 Jan 2022 : 13:58:05
| If heavy honing gets rid of the black splodges/corrosion it might might be usable as is. Are all bores like that? Otherwise a rebore is on the cards. | |
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SAAB96L V4 Mad
United Kingdom 501 Posts | Posted - 25 Jan 2022 : 19:11:55
| Hello Andy,
The black spots are usually signs of water ingress into the cylinder bores, either as a result of a failed head gasket or poor storage allowing moisture to settle against the bores as the thin oil mist disappears. As a result the corrosion eats into the bore & becomes less smooth, then as the piston travels up and down it catches (picks-up) on this and accelerates the wear producing these permanent black spots.
The issue with heavy honing is that you enlarging the bore dimension and that will allow greater gapping between the rings and the bore with the inevitable burning of oil plus a reduction in performance due to a reduction of compression.
By all means go for the hone, but it will be a case of spending twice to properly rectify the issue.
What's the history of the engine ??
Regards.
Richard. | Edited by - SAAB96L on 25 Jan 2022 19:13:42 | |
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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 25 Jan 2022 : 19:51:57
| My mate bought the car as a part finished project, which he has completed, but I don't think he knows anything about the history of the engine.
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | |
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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 25 Jan 2022 : 19:54:17
| quote: Originally posted by Derek If heavy honing gets rid of the black splodges/corrosion it might might be usable as is. Are all bores like that? Otherwise a rebore is on the cards.
Derek I'll have a look at the other bores next time I'm up at my mate's place.
Andy
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | |
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Woody V4 Guru
United Kingdom 2758 Posts | Posted - 26 Jan 2022 : 10:11:57
| Might as well strip it down. Have block and crank and pistons checked at an engine shop. They will advise if light hone will do the trick. Good opportunity to check condition of Cam and balance shaft bearings. My 1971 block was stripped at 115000 miles as core plug rotted and the top end needed a decoke. Bores were glaze busted and new cam and balance shaft bushings were put it, and new piston rings after the pistons were cleaned up. Had new mains and big ends. This was in 1987 when parts availability was good. | |
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Derek V4 Guru
United Kingdom 2187 Posts | Posted - 26 Jan 2022 : 12:22:58
| I was saying heavy honing as apposed to just a glaze busting exercise. What's shown looks to be beyond the capabilities of multi ball hone. A rebore is never cheap but it will fix the problem. | |
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SAAB96L V4 Mad
United Kingdom 501 Posts | Posted - 26 Jan 2022 : 14:46:14
| Agreed, Derek, a rebore is the logical route and best option. | |
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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 26 Jan 2022 : 16:46:02
| Chaps Re-boring is an obvious answer, but where do you get the oversized pistons from? I'm led to believe, (please correct me if I'm wrong), that you would have more chance of finding a hen with teeth, (or hear a well known politician telling the truth), than be able to source decent, oversize pistons!
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | Edited by - andydeans3 on 26 Jan 2022 16:47:13 | |
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SAAB96L V4 Mad
United Kingdom 501 Posts | Posted - 26 Jan 2022 : 18:35:11
| If you are going for oversize, then I would suggest that the bore is taken out to accommodate alternative marque pistons - pinto might be an option ??
They are the pistons I will be using, albeit the engine is being increased in cc significantly; which may preclude pinto for what you want Andy.
I'm sure there is a pinto guru on here that can advise, if that is an option for your requirements.
Regards.
Richard
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christophe V4 Fanatic
France 224 Posts | Posted - 26 Jan 2022 : 20:03:20
| Motomobil got them, but at 129€ each. | |
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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 26 Jan 2022 : 21:39:39
| quote: Originally posted by SAAB96L If you are going for oversize, then I would suggest that the bore is taken out to accommodate alternative marque pistons - pinto might be an option ??
They are the pistons I will be using, albeit the engine is being increased in cc significantly; which may preclude pinto for what you want Andy.
I'm sure there is a pinto guru on here that can advise, if that is an option for your requirements.
Regards.
Richard
If I'm not mistaken, pinto pistons are only used in 1700 cc engines. For 1500 cc engines you cannot use Pinto pistons. I was hoping that Melle would come on, he's the guru on this sort of stuff!
I should point out that this is not my engine, it belongs to another 96er in the county.
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | Edited by - andydeans3 on 26 Jan 2022 21:46:32 | |
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andydeans3 V4 Guru
United Kingdom 1994 Posts | Posted - 26 Jan 2022 : 21:41:43
| quote: Originally posted by christophe Motomobil got them, but at 129€ each.
Pistons for 1500cc engines, or Pinto pistons?
1978 LHD SAAB 96 1978 MGB Roadster 2008 LHD "Classic" Renault Twingo 1991 Nissan Figaro | |
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christophe V4 Fanatic
France 224 Posts | Posted - 27 Jan 2022 : 07:16:06
| As far as I can say, they seem to have pistons for every iteration of the Cologne engine. Burton mentions the use of 94mm Pinto pistons, by the way. | |
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