Discussion
If you are going to open the engine then go all the way and get it refurbished throu out. Get it bored to first over size +0.020 and give it new bearings, pistons etc. Would be roughly 1000£ in total, and you have a spinning and smoke free engine (and the work is mor or less the same)
Fiscracer said:
No need for a rebore unless its scored just hone it. Also check valves seals and seats cos if compression is OK its unlikely to need rings. How well is the crankcase vented?
R
No idea about that. I've got the rocker cover going to a separate vent chamber. R
How do you vent that?
Stevo302 said:
No idea about that. I've got the rocker cover going to a separate vent chamber.
How do you vent that?
If the lower crankcase is pressurising it will make the engine breathe heavily. On my Chevy V8 we have used the hole for the mechanical fuel pump; on my MGB and TVRs it's from the tappet chest; on my Midget it's the timing cover and on my Volvo B18 there is a standard breather. They're all race engines ;-). How do you vent that?
Neil may have an alternative suggestion for a Ford V8
Not saying that's the cause but if you are going to pull it apart anyway, I would certainly put a breather on the bottom end.
Fiscracer said:
If the lower crankcase is pressurising it will make the engine breathe heavily. On my Chevy V8 we have used the hole for the mechanical fuel pump; on my MGB and TVRs it's from the tappet chest; on my Midget it's the timing cover and on my Volvo B18 there is a standard breather. They're all race engines ;-).
Neil may have an alternative suggestion for a Ford V8
Not saying that's the cause but if you are going to pull it apart anyway, I would certainly put a breather on the bottom end.
I am getting confused…Are we talking crossflows or straight 6's V8's or general engines..Neil may have an alternative suggestion for a Ford V8
Not saying that's the cause but if you are going to pull it apart anyway, I would certainly put a breather on the bottom end.
Engines can breathe for a number of reasons..fuming from the rocker cover can mean piston wear or valve guide wear..
On my V8 both rockers are vented to a tank and the tank has a foam filter…It still breathes but not heavily..
If you have good compression and all even then you may have valve guide issues
Lower crank pressure is almost always blow bye past the rings…
On v8's you may have little perceived wear in terms of scoring but ovality in the bore may be preventing rings doing their job efficiently, this may not always be noticeable on a cranked compression test
On any engine, how heavily it breathes, what the idle and 3000rpm oil pressure reads and general oil consumption is all a factor..
Engines that are just generally worn have probably been honed and re-ringed before.. Only way to make the correct decision is to strip and measure the clearances and ovality present..
Don't be too keen to bore a ford block..they aren't like heavy chevy's. Thin wall castings mean you should never bore beyond 40 thou..You will find some out to 60 thou, alright for a banger but not a performance engine
Straight 6's are old fashioned and can be re-built fairly easily since plenty scope for boring. The crank is also a meaty item Before you buy a re-build kit you need to see whether it has been bored before?? only way is to strip and measure..
if your engine has had thrust washer issues or has crank thrust now then expect to find oval bores.
This is interesting..
http://t2000.kvaleberg.org/t_tune.html
http://www.triumphowners.com/registry.cgi?sectionI...
N.
Edited by Dollyman1850 on Saturday 7th February 10:20
Edited by Dollyman1850 on Saturday 7th February 10:27
Edited by Dollyman1850 on Saturday 7th February 10:30
Edited by Dollyman1850 on Saturday 7th February 10:40
Sorry, I didn't read the opening post thoroughly, until now. Even though I don't know, what you mean by heavy breather, I will wager that it's blowing blue smoke out of the exhaust, and oil vapor, out of the valve cover breather. As compression is good, the bottom end may need no work, at all.
You will have to replace the valve seals, but in all likelihood, also the guides* and valves**. TR6 heads are steel, not cast Iron, so you won't have to install inserts, but you can use larger valves, while you're at it, and gain performance. Have a competent machine shop cut a multi-angle valve seat, at the same time. Porting is a big factor, in gaining performance.
The TR6 heads came in different guises, and I'd research which one you have, before investing too heavily, in one. Look for the large intake port version. There are casting marks***, which identify the various versions, and some would try to pass off GT6 heads as TR6. Don't bother, with those. The port diameter and spacing are less than ideal.
Best regards,
Bernard.
* There are a couple of different Bronze (alloys) guides available, each is somewhat better, i.e. longer lasting, than the stock cast iron type.
** Stainless Steel versions are more durable.
*** I seem to remember a diamond, with a letter in it, near the back of the head, under the valve cover, as being a distinguishing mark of one large port versions.
You will have to replace the valve seals, but in all likelihood, also the guides* and valves**. TR6 heads are steel, not cast Iron, so you won't have to install inserts, but you can use larger valves, while you're at it, and gain performance. Have a competent machine shop cut a multi-angle valve seat, at the same time. Porting is a big factor, in gaining performance.
The TR6 heads came in different guises, and I'd research which one you have, before investing too heavily, in one. Look for the large intake port version. There are casting marks***, which identify the various versions, and some would try to pass off GT6 heads as TR6. Don't bother, with those. The port diameter and spacing are less than ideal.
Best regards,
Bernard.
* There are a couple of different Bronze (alloys) guides available, each is somewhat better, i.e. longer lasting, than the stock cast iron type.
** Stainless Steel versions are more durable.
*** I seem to remember a diamond, with a letter in it, near the back of the head, under the valve cover, as being a distinguishing mark of one large port versions.
I see that you have the extra oil line in the cylinder head which is not a bad thing to do, but by doing this there will be much more oil pushed in the cylinder head if you don't convert the valve guides with proper valve seals a t least at the intake valves your engine will start to smoke, original they are using just an O-ring as a seal which kind of works.
All the engines I have done we convert them to bronze valve guides with seals and the heads are cast by the way.
All the engines I have done we convert them to bronze valve guides with seals and the heads are cast by the way.
Gassing Station | TVR Classics | Top of Page | What's New | My Stuff