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TR2/3/3A Engine refresh
- Thread starter Hamish Racing
- Start date
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OP
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I found reference to using 48ftlb for the big end arp 3/8”bolts
105ftlb to do the head is a bit scary !!!
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TR4nut
Yoda
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Thanks! The TR6 rods use 5/16" so torque is quite a bit less - also scary for me as I don't have a strain gauge, don't want the bolts too loose and don't want them too tight! I've settled on 29 ftlbs, less than 32 ftlbs which ARP quotes but more than 26-28 which is what I found on the MaxSpeeding rods website.
OP
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I’m guessing this post is in the wrong place ?
mastaphixa
Jedi Trainee
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I feel like I came in half way thru this movie.
OP
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Nice Picks Hamish. Leaving the crank in is the beauty of these cars. I have done it that way and the engine came back to life just fine. I have no insight of why the piston broke, and I am looking forward to hear what is said.
Do I see 2 coils? Is the one coil a spare? Moreover, are the larger hoses for water circulation?
I am building motor also so this post really helps. I have some of those rods I bought used, and cannot decide if I should use them or go with original rods. Please keep posting
Steve
Do I see 2 coils? Is the one coil a spare? Moreover, are the larger hoses for water circulation?
I am building motor also so this post really helps. I have some of those rods I bought used, and cannot decide if I should use them or go with original rods. Please keep posting
Steve
OP
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The conclusion from wiser people than I on the piston break is
A. Over revved (6250rpm Rev limiter
B. Rings too tight ( not sure on this as they did 3+ seasons
C. Just used up the strength and durability capacity on what are essentially road tune pistons
I think it’s a combination of A and C
Yes 2 coils - one is a spare
Big pipe on left (with copper bends) are my crank case breather into an oil catch tank and a vent out of this tank. There is a smaller bore breather from the rocker cover.
Certainly use the MaXpeeding rods they are great. New big end shells and the little end shouldn’t have much wear so the wrist pins should fit.
My head has been worked on for gas flow with bigger valves and ported.
I take the inlet and exhaust studs out to aid head removal as my sports exhaust manifold won’t move clear of them. To aid stud refitting I put a simple cut across the end do I can screw them back in with a screw driver. With a little copper grease on the threads.
This is later on with the exhaust and carbs fitted.
Yet to fit sump and set tappets/valves and fill with oil and coolant.
A. Over revved (6250rpm Rev limiter
B. Rings too tight ( not sure on this as they did 3+ seasons
C. Just used up the strength and durability capacity on what are essentially road tune pistons
I think it’s a combination of A and C
Yes 2 coils - one is a spare
Big pipe on left (with copper bends) are my crank case breather into an oil catch tank and a vent out of this tank. There is a smaller bore breather from the rocker cover.
Certainly use the MaXpeeding rods they are great. New big end shells and the little end shouldn’t have much wear so the wrist pins should fit.
My head has been worked on for gas flow with bigger valves and ported.
I take the inlet and exhaust studs out to aid head removal as my sports exhaust manifold won’t move clear of them. To aid stud refitting I put a simple cut across the end do I can screw them back in with a screw driver. With a little copper grease on the threads.
This is later on with the exhaust and carbs fitted.
Yet to fit sump and set tappets/valves and fill with oil and coolant.
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Last edited:
CJD
Yoda
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If the rings were set to tight, you would have noticed a loss of power and increase in engine heat as you warmed up on the long straights. Also would have caused worse problems shortly after installation...so not likely this far down the road.
I doubt the overspeed hurt the lands, so my money would be cast pistons and occasional detonation. Forged would survive a bit longer, but same result eventually.
I doubt the overspeed hurt the lands, so my money would be cast pistons and occasional detonation. Forged would survive a bit longer, but same result eventually.
OP
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I have skimmed the pistons an extra 5thou to reduce compression a bit. And I’ll check timing.
But I’m sure the ring landing went first and then the detonation started as the only piston damage from detonation is only on the one with ring landing damage.
No pinking or any signs eg smoke but perhaps that one pot was running like a 2 stroke ?
It ran very well with the piston landing damage just like the end of last year
But I’m sure the ring landing went first and then the detonation started as the only piston damage from detonation is only on the one with ring landing damage.
No pinking or any signs eg smoke but perhaps that one pot was running like a 2 stroke ?
It ran very well with the piston landing damage just like the end of last year
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OP
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Update
it runs
after a lot of hours over the week, I was able to do about 5 hours this evening. Block cleaned for sump fitting. Gasket fitted to sump. Struggled to lift sump on to block despite using a jack. New oil filter.
6.5L oil in. Coolant in.
tappets set.
engine turned over and over on the solenoid button to get oil pressure and oil flow out of rockers.
plugs in. Dizzy cap on etc.
i must be very slow as I didn’t stop and it all took ages.
i then bit the bullet and it fired right up. Gave it a short run no nasty noises and it seems to Rev ok. Some smoke but just from oily hand prints etc.
all off and happy. Final check round and a pool of oil under the car.
it was just the sump drain bolt. I hadn’t tightened it up phew.
need to juggle camper and Alvis to get the tr out for road test snd a bit of ring bedding in.
I’m still keeping my fingers crossed.
it runs
after a lot of hours over the week, I was able to do about 5 hours this evening. Block cleaned for sump fitting. Gasket fitted to sump. Struggled to lift sump on to block despite using a jack. New oil filter.
6.5L oil in. Coolant in.
tappets set.
engine turned over and over on the solenoid button to get oil pressure and oil flow out of rockers.
plugs in. Dizzy cap on etc.
i must be very slow as I didn’t stop and it all took ages.
i then bit the bullet and it fired right up. Gave it a short run no nasty noises and it seems to Rev ok. Some smoke but just from oily hand prints etc.
all off and happy. Final check round and a pool of oil under the car.
it was just the sump drain bolt. I hadn’t tightened it up phew.
need to juggle camper and Alvis to get the tr out for road test snd a bit of ring bedding in.
I’m still keeping my fingers crossed.
OP
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The intention was to have less so aimed for 9.5 / 9,8 with a slightly less piston height.
It was 10
I may also be moving to 123 ignition to get more reliable and accurate timing. Just in case the detonation issues came first.
I’ll check the pure compression once it’s all run in.
OP
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I managed some road time this evening just up and down a local bypass with mainly 50mph limits and lots of roundabouts.
I have had much advice about running in. As mine is not a full rebuild the crank and cam don’t need anything much the old big end bearing where reused as they were ok and only had a few hundred miles on them so it’s mainly the rings and bores.. the bores where quite heavily hones tho.
Bill my old mate who has over 60 decades of race car experience suggested only minimal light running.
other tr racers has suggested a lot of high gear WOT preferably up a long hill and then some over run.
i have done 30 miles tonight only up to 3.5k revs a lot of wot in 4th and 4th od.
and with the roundabouts it was dispersed with lots of through the gears variable speeds revs. But nothing crazy.
no clouds of smoke out the back, revs nicely and pulls well in 4th.sounds good (as usual) oil pressure is the same usually high level, and coolant temps in the usual range 185-200f the elec fan didn’t cut in whilst moving.
on my return I pulled a couple of plugs and it’s running really rich, very sooty. I do run it rich as it’s safer than lean but I think too rich.
I have had much advice about running in. As mine is not a full rebuild the crank and cam don’t need anything much the old big end bearing where reused as they were ok and only had a few hundred miles on them so it’s mainly the rings and bores.. the bores where quite heavily hones tho.
Bill my old mate who has over 60 decades of race car experience suggested only minimal light running.
other tr racers has suggested a lot of high gear WOT preferably up a long hill and then some over run.
i have done 30 miles tonight only up to 3.5k revs a lot of wot in 4th and 4th od.
and with the roundabouts it was dispersed with lots of through the gears variable speeds revs. But nothing crazy.
no clouds of smoke out the back, revs nicely and pulls well in 4th.sounds good (as usual) oil pressure is the same usually high level, and coolant temps in the usual range 185-200f the elec fan didn’t cut in whilst moving.
on my return I pulled a couple of plugs and it’s running really rich, very sooty. I do run it rich as it’s safer than lean but I think too rich.
Last edited:
CJD
Yoda
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If seating rings is the priority, this is the break-in recommended by my 1974 Auto-class Manual for old-school cast iron rings and cylinders:
Take it out in a higher gear and floor it between about 2000 and 5000RPM. Then, come off the gas and let it coast back down to 2000RPM in the same gear. Repeat about a dozen times and that should do it for the rings. The book says that flooring it loads the rings against the cylinder walls, thereby accelerating the break-in time. Coasting creates high vacuum in the cylinder to draw oil into the rings and cool them back down.
If your rings are moly-faced on a finely honed cylinder, then break in is not necessary. Finally, if the rings or cylinder are chrome plated...then break-in may take months!
Take it out in a higher gear and floor it between about 2000 and 5000RPM. Then, come off the gas and let it coast back down to 2000RPM in the same gear. Repeat about a dozen times and that should do it for the rings. The book says that flooring it loads the rings against the cylinder walls, thereby accelerating the break-in time. Coasting creates high vacuum in the cylinder to draw oil into the rings and cool them back down.
If your rings are moly-faced on a finely honed cylinder, then break in is not necessary. Finally, if the rings or cylinder are chrome plated...then break-in may take months!