The ยฃ7700 Corvette C6

The ยฃ7700 Corvette C6

Author
Discussion

Fishy Dave

Original Poster:

750 posts

209 months

Wednesday 6th January
quotequote all
F1natic said:
Fantastic write up Dave, really enjoy reading about your work and the christmas presents you give yourself - I also admire your "get stuck in" approach, certainly paid off handsomely with those head studs. I am amazed the engine mounts were not thumping, they were tucked. Greatly appreciate you posting the how to pics for the bushes and the links to the suppliers, will be needing to do similar for mine in the near future but don't want to buy the shop manual as I am only using the C6 suspension, not the whole car. Looking forward to your review after driving, since you have such a good baseline to start from.
Thanks, I will certainly report back once the car is back on the road. Whilst we are locked down I am debating whether to carry out some preventative work in the engine, namely changing the valve springs and perhaps uprate the rocker bearings too whilst I'm in there. idea 'Janosh' started me thinking, as he'd experienced a broken spring in his VXR8 with the same engine.

Fishy Dave

Original Poster:

750 posts

209 months

Wednesday 6th January
quotequote all
daniel-5zjw7 said:
Some great work there, getting those studs out must of felt great smile regards the engine mount I had one just like that on my old e46, it suprised me too as i felt sure I would have noticed something not right, but i had no clue, only found it as was upgrading anyway.

How are you finding the new mounts? I need to put some new ones on my list at some point but not sure if i'll go standard or upgrade.

Keen to hear your thoughts on the dampers/bushes, any reason you decided against coilovers/removing the leafs?
Thanks, yes, I really felt good that I'd managed to get those studs out, mostly on the basis of some youtube videos. smile Glad I'm not the only one to have not felt a broken mount.
The car is still on the lift, so I'm not sure how they feel yet, but they do look faster when I peek at them biggrin

As for why I stuck with the leafs, well, I like the way the car handles on them, they are lighter than coiled springs, I don't have to use spring compressors, adjusting ride height couldn't be easier, it was as Chevrolet intended and I'm a bit stubborn rolleyes Many, many times I've read about how those who converted to coil overs noticed a massive improvement, therefore the leaf's must be rubbish. My suspicion is that what they are actually feeling is an improvement in damper and most likely a geometry set up at the same time. Oh, the final reason is that many unknowing Brits brought up on Clarkson expect the cars 'cart springs' to deliver an awful ride and handling, so it's gratifying to hear their positive reaction once they've had a few pax laps. wink

As mentioned above, I will certainly report back once I have driven the car. I have booked an OpenTrack trackday at Thruxton on 8th March for the Corvette and my E90 320si, that should be a good work out for both. I have to hope the Corvette will be quiet enough to pass noise with the NPP exhaust valves closed. shoutwhistle

MrNoisy

446 posts

105 months

Wednesday 6th January
quotequote all
Dave,

Got your email, all sounds very interesting and you can count me in biggrin

Amazing work on the studs, taking the heads off again would have been a right pain but welding in those confines - impressive. I would have set fire to the car for sure.

Be really interested in how you get on with the delrin as you use the car on the road so much. I did 2019s black friday deal and I know what you mean, the package is a work of art! That's my excuse for only getting around to fitting them last summer. Having done plenty of bushes (oor errr) on old landies and scoobies I was prepared for a big fight but mine literally wound out with a universal puller. I see your front uppers were beginning to walk as well. I'm not surprised with the way you brake biggrin I love how they changed the car but my originals had over 100k on them and were soft as you like. Much more controlled but not without compromise.

I fitted 'Hinson Supercar' Poly mounts way back when in the States as my fluid filled mounts had ceased to be fluid filled. The tell tale is the orange staining on the subframe. As you say, it's impossible to see normally and also very difficult to feel. I have to confess to taking them out and putting stock back in though, I didn't get on with them on the road and then was doing 12k a year commuting. I also did the tranny mounts in the same though so overall it got much stiffer. Lovely on the trackday I did on them but as my DD it was too much. As the car is basically a garage ornament/track toy now I have been scouring the ads in the USA for another set. Again, really interested in how you like those you have.

Looks like any chance I was dreaming of hanging on for a few corners has just gone up in smoke biggrin

Fishy Dave

Original Poster:

750 posts

209 months

Friday 8th January
quotequote all
MrNoisy said:
Dave,

Got your email, all sounds very interesting and you can count me in biggrin

Amazing work on the studs, taking the heads off again would have been a right pain but welding in those confines - impressive. I would have set fire to the car for sure.

Be really interested in how you get on with the delrin as you use the car on the road so much. I did 2019s black friday deal and I know what you mean, the package is a work of art! That's my excuse for only getting around to fitting them last summer. Having done plenty of bushes (oor errr) on old landies and scoobies I was prepared for a big fight but mine literally wound out with a universal puller. I see your front uppers were beginning to walk as well. I'm not surprised with the way you brake biggrin I love how they changed the car but my originals had over 100k on them and were soft as you like. Much more controlled but not without compromise.

I fitted 'Hinson Supercar' Poly mounts way back when in the States as my fluid filled mounts had ceased to be fluid filled. The tell tale is the orange staining on the subframe. As you say, it's impossible to see normally and also very difficult to feel. I have to confess to taking them out and putting stock back in though, I didn't get on with them on the road and then was doing 12k a year commuting. I also did the tranny mounts in the same though so overall it got much stiffer. Lovely on the trackday I did on them but as my DD it was too much. As the car is basically a garage ornament/track toy now I have been scouring the ads in the USA for another set. Again, really interested in how you like those you have.

Looks like any chance I was dreaming of hanging on for a few corners has just gone up in smoke biggrin
I will confess to having a powder extinguisher on standby. furiouseek
I had no idea you had the same kit fitted, I should have thought to ask you. Good that you like that change, but presume the compromise is a harsher ride? Did you make any other changes at the same time as fitting them?

Worrying about what you've reported about the engine mounts, the AMT mounts don't look especially cushioned. bounce I just need to man up and remember my hardcore days of running a Caterham as my daily.

Don1

14,323 posts

172 months

Saturday 9th January
quotequote all
Loving the stud removal work.

MrNoisy

446 posts

105 months

Sunday 10th January
quotequote all
Fishy Dave said:
I will confess to having a powder extinguisher on standby. furiouseek
I had no idea you had the same kit fitted, I should have thought to ask you. Good that you like that change, but presume the compromise is a harsher ride? Did you make any other changes at the same time as fitting them?

Worrying about what you've reported about the engine mounts, the AMT mounts don't look especially cushioned. bounce I just need to man up and remember my hardcore days of running a Caterham as my daily.
The ride was significantly harder following fitting the Delrin but for me that was overall a good thing. My front bushes were so worn the car darted about on B roads.

I swapped out the bars and shocks for Pfadt Johnny o Connell stage 1 back in 2012. This tightened things up significantly. As we chatted about before I put as new Z06 springs on in 2013, another level of stiffening. I think it was about 2014/15 I did the engine and tranny mounts (having noticed the orange staining).

The engine/driveline noise transferred to the cabin was just too much for a car I was spending over two hours a day in.

I’m glad you went for the same kit as me, makes me feel the research paid off if we both independently came to the same conclusion 😎

Fishy Dave

Original Poster:

750 posts

209 months

Tuesday 12th January
quotequote all
Whilst I can't really drive the Corvette during the winter lockdown, it's the right time to carry out some preventative work on the car. It's hard to throw away and replace items that are working ok, but the potential costs from a valve spring or rocker failing at full throttle on track would be far more expensive. There are so many options for LS engines, it makes it quite difficult to work out what to chose on a budget.

In the end I went for this little lot:
https://www.summitracing.com/parts/sme-k-14300
This upgrade kit includes
Trick Flow Specialties TFS-16918-16 - Trick Flow® by PAC Racing Beehive Valve Springs
Summit Racing SME-143002 - Summit Racing® LS Series Retrofit Rocker Bearing Trunnion Upgrade Kits and installation tool
Summit Racing SME-143008 - Summit Racing® Viton Valve Seals
Summit Racing SME-143009 - Summit Racing® Valve Locks (Collets)

A valve holder https://www.summitracing.com/parts/lil-19700 just a simple air line that screws into the spark plug hole, compressed air then stops the valves from dropping into the cylinders when the valve locks and springs are removed.

Trick Flow® Chromoly Pushrods TFS-21407400 https://www.summitracing.com/parts/tfs-21407400

I also ordered a set of cooler, LS7 spark plugs and replacement AC Delco RR silicone leads, to replace a few I had broken when trying to remove them (I'll change them all).



Had my budget been greater I'd have gone for titanium springs caps too, but decided to stick with the stock ones. None of these parts will gain me any extra power, but all the ingredients are in place should I choose to add a hotter camshaft at a later date (no plans to though).

The spark plugs and leads were still out due to removing the broken exhaust studs. I removed the rocker covers, rockers and pushrods. The original springs are yellow.





With my fingers constantly covered in oil my photo taking was a bit limited. This shows part of the 'Three Mirrors' brand spring compressor (excellent) having removed the old spring and collets and I've just pulled off an old valve stem seal.



Every part I removed was in perfect condition, no wear visible after 214,000 miles. There was some carbon/oil build up under some of the seals, but no harm seems to have come of it.



New and old valve springs.



Spring specs. They are fine with my stock cam and will support a 'warm' cam, but nothing too wild.



New and old pushrods.




Some of the guides had described using a blob of grease to stick the new collets in place to the shaft of the valve, so that as you release tension on the spring compressor tool they stay in place. I didn't need to do that, they stayed pretty well, I used my drill/driver to slowly unwind the nut on the tool. A magnet caught the odd one that fell out.

The rocker upgrade kit comprised of new centres, roller bearings and clips on each end to keep everything in place. The oem rocker bearings by comparison are pressed in and can walk their way out in extreme cases. I am very glad the Summit kit I bought came with their bearing removal and refitting tool. Used with a vice the job was straightforward, if a little production line like. The instructions recommended a particular grease for bedding in, I wish they'd included some, instead i used thick moly grease for CV joints.





A finished rocker, with clips on the ends to keep the roller bearings in place.


A box of old bits removed from the engine.


Last night I bolted the rockers back in to the correct 22lbft torque with locktite, that's as far as I've got. I'll hopefully finish the car at the weekend and report back. smile

Edited by Fishy Dave on Tuesday 12th January 22:55

SturdyHSV

7,881 posts

131 months

Wednesday 13th January
quotequote all
Some good sensible upgrades there, the LS valvesprings aren't a particular issue with a standard cam (Janosh's isn't) but it can't hurt to replace them after 214,000 miles given you work it hard smile

From my reading, the stiffer pushrods and springs will effectively mean more of what the cam asks for will make it to the valve, it sort of makes the cam act a touch 'bigger' but will be curious to see if it's vaguely noticeable. You might find it's a little stronger above 6,000rpm or so although starting to move out of the cam's comfort zone up there of course.

Sensible job on the rocker arms too, and going for the 'top hat' style valve stem seals. I used those 2 piece ones with separate spring seats and (presumably due to installation error) found they let some oil by, so swapped to a new set of the top hats and was sorted.

In the spirit of bodgery / lazyness, if you don't have the spark plug air tool, just turn the engine over by hand so the piston is at / near TDC (I just popped a straw in the spark plug hole and rotated until the piston pushed the end of it), the valves then can't drop enough to fall in so you can just carry on with the spring / seal swap in safety. To be fair with only a 3.622" stroke they probably wouldn't be able to fall in enough unless it was right at BDC but who wants to test that theory wink

I did the engine mounts on my LS2 Monaro, went with the Hinson Supercar ones and yep, mine were exactly the same as yours, after only about 60,000 miles yikes

I replaced the trans mount with a new OEM one that I then did the 'window weld' mod on, basically filling the gap in the mount with a rubber compound that dries hard called window weld. It made very little difference to NVH (a harsh trans mount is main the thing to avoid to keep it civil) but it transformed the gear shift as the stick was no longer jumping about when you lifted off to change gear! That's obviously not with a torque tube / transaxle set-up though so will be curious to see how it feels.

I suspect it was placebo but it felt like there was a little more urgency in throttle response, just a little less slop in the drivetrain, but I don't imagine I could actually feel that, and was just imagining it hehe

Fishy Dave

Original Poster:

750 posts

209 months

Monday 1st February
quotequote all
Well, my two trips to collect the shopping from Sainsburys are hardly a comprehensive review, but it's given me enough to go on.


First time I drove the car I actually thought I had a fault, the vibration pulling away and at low revs made me think the engine or transmission was actually touching the chassis. No, the engine mounts are just as good at transmitting vibrations as you'd reported Mr Tidy. headache The sum of the changes combined actually make it feel like a different car, it's going to take a few laps to get used to it again.

The ride is firmer, but is not bad at all. I wish I could have changed just the shocks or the bushings and driven it for a while, to have better appreciated their individual contributions. For now I am using the factory recommended settings on the KW's, but will experiment in the warmer months when/if the lockdown ends. I'm currently awaiting a reply from KW UK, having passed on detailed feedback about instructions, settings and 'ease' of adjustment.......

There is slightly less popping from the exhausts on deceleration, which was expected now that the manifolds seal correctly, still enough to bring on a childish grin though.

I'd like to report a bit more power SturdyHSV, but with greasy roads and the car likely to attract the wrong kind of attention I didn't go too crazy. Oh and the gear lever barely moves, perhaps down the the torque tube as you mentioned. Thanks for your suggestion about using the TDC method to stop the valves falling in the cylinders, the challenge with the C6 is that the steering rack blocks access to the main pulley bolt and the rack is a PITA to move.

Nice to see a bit of snow last week, first time I've seen any in Wiltshire for two years.



My spending to finish the month of January has thankfully been restricted, to just £11 of finest Chinese ebay produce. To protect the spark plug leads the Corvette comes with alloy tubes. Sure enough, they have done their job, only they get in the way when trying to remove the plug leads, with the leads almost always tearing. This time I replaced the tubes with some heat resistant socks.




SturdyHSV

7,881 posts

131 months

Wednesday 3rd February
quotequote all
Fishy Dave said:
heat resistant socks.
You look to have the original exhaust manifolds so this is likely not an issue, but keep an eye on the socks.

I have aftermarket exhaust manifolds and they bring the primary a bit closer to the plug lead and I had some issues with boot / leads cracking due to the heat.

I thought some socks would help, got some apparently high temp red ones from Summit, all this turned out to do was remove the air gap between the pipe and the boot, and ultimately meant it burnt through the boot even quicker and more successfully...

The MSD style HT lead boots are flexible and can be bent away from the header and I've found the air gap more successful in protecting the leads than the socks were.

Your mileage may vary of course and as I say, stock manifolds means it's less likely to be an issue, but something to cast an eye over after a track day perhaps, and maybe keep a couple of spare leads in the boot! hehe

Fishy Dave

Original Poster:

750 posts

209 months

Wednesday 3rd February
quotequote all
Yes, still the original manifolds. Oh dear, that doesn't make for very good reading about the socks, then again, the stock alloy shields probably weren't the greatest either? I'll certainly keep an eye on the leads, thanks for the warning. smile

F1natic

259 posts

20 months

Saturday 6th February
quotequote all
Completely random question but I don't suppose any of you C6 guys happen to know the length of the C6 fuel pump? I am using one in my build and am struggling to find any decent dimensional info on the web. Thanks.

Fishy Dave

Original Poster:

750 posts

209 months

Saturday 6th February
quotequote all
F1natic said:
Completely random question but I don't suppose any of you C6 guys happen to know the length of the C6 fuel pump? I am using one in my build and am struggling to find any decent dimensional info on the web. Thanks.
No, sorry, a quick question on the US Corvette forum would probably get you an answer though. Like you, I've googled for ten minutes but can't find dimensions. frown What is the build?

SturdyHSV

7,881 posts

131 months

Saturday 6th February
quotequote all
Fishy Dave said:
What is the build?
Oh you're in for a treat, he's effectively building a McLaren F1 but a touch more technical.

This thread delivers:

https://www.pistonheads.com/gassing/topic.asp?h=0&...

JulianPH

9,079 posts

78 months

Saturday 6th February
quotequote all
Absolutely brilliant journey and thread. I doff my cap to you!


Fishy Dave

Original Poster:

750 posts

209 months

Tuesday 9th February
quotequote all
JulianPH said:
Absolutely brilliant journey and thread. I doff my cap to you!
Thank you, I've been happy to share the journey. I'm currently dreaming up the next adventures for the car. smile

Edited by Fishy Dave on Tuesday 9th February 18:01

DaveCWK

1,501 posts

138 months

Tuesday 9th February
quotequote all
Love this; great thread.