Two new racecars in NZ
- Thread starter Frans
- Start date
Sorry to hear of your misfortune. Hope it can be fixed without too much grief.
Sorry about that news Frans. Look forward to the post mortem anyway!
So right.Thanks for the sympathybut I guess that is racing. There are times when you're the windscreen and then there are times when you're the bug.
Frans.
I always thought it was a tree and a dog Fran's
The post mortem on the race car's blown engine turned out to be the cylinder head. While the dry-sump engine components are at the engine shops, I was feeling a bit bored, so I took the engine out and stripped it halfway. The gasket was blown at no.3 and then I backtracked history and realised it is the 3rd time since 2017 and at the same spot. In hindsight, I should have checked more closely the first time. Hindsight means less than zero.
I cleaned the block and did a protrusion check. It checked out okay with .003" protrusion each of the 4 sleeves plus the .004" of the ridge that I normally cut in on the top. I feel like shimming the sleeves another .001" for safety sake.
Then I shifted my attention to the head. I think it is wasted. I would like some insights from others. The head cannot be skimmed any more unless a spacer is used. Has anybody used spacers on a wet sleeve motor? If it can be skimmed with a spacer I still think the head has seen better days because it has warped between the head bolts along all 4 combustion chambers. ie. the straight edge gives me a good reading from the front head bolt right through the middle ones to the rear. That means the head is straight on average but at each combustion chamber, there is a hollow. Is that because the head went soft?
At every head bolt along the head, the .001" blade got stuck
In between the head bolts is a gap that is about equivalent to the sleeve protrusion.
The worst one measures .004" but it looks like I never took a photo or else deleted it accidentally.
I think that this distortion over such a short distance is "throw away time." I have had a lot of fun with it and it was in use for 12 years. The first race being 2009. So depending on a brilliant idea from someone, I will dig into my spares and get no. 2 sorted.
Regards, Frans
I cleaned the block and did a protrusion check. It checked out okay with .003" protrusion each of the 4 sleeves plus the .004" of the ridge that I normally cut in on the top. I feel like shimming the sleeves another .001" for safety sake.
Then I shifted my attention to the head. I think it is wasted. I would like some insights from others. The head cannot be skimmed any more unless a spacer is used. Has anybody used spacers on a wet sleeve motor? If it can be skimmed with a spacer I still think the head has seen better days because it has warped between the head bolts along all 4 combustion chambers. ie. the straight edge gives me a good reading from the front head bolt right through the middle ones to the rear. That means the head is straight on average but at each combustion chamber, there is a hollow. Is that because the head went soft?
At every head bolt along the head, the .001" blade got stuck
In between the head bolts is a gap that is about equivalent to the sleeve protrusion.
The worst one measures .004" but it looks like I never took a photo or else deleted it accidentally.
I think that this distortion over such a short distance is "throw away time." I have had a lot of fun with it and it was in use for 12 years. The first race being 2009. So depending on a brilliant idea from someone, I will dig into my spares and get no. 2 sorted.
Regards, Frans
Beyond my pay grade Frans but it doesn't look good, does it? I'll await Mr Geckoeng's opinion. I presume the localised warping took the compression off the gasket around the sleeve top.
I have heard of these heads being built up with welding and refaced to bring back thickness. I've also heard of the them getting too hot and softening, which I presume could be reversed with the right heat treatment but I don't know.
You can be relied upon for teaching many of us interesting lessons!!
I have heard of these heads being built up with welding and refaced to bring back thickness. I've also heard of the them getting too hot and softening, which I presume could be reversed with the right heat treatment but I don't know.
You can be relied upon for teaching many of us interesting lessons!!
I thought you could have these heads loaded with weld and re-machined? I mean it is such an important and expensive item I am not sure you would want to give it up.
What is it like on the intake side? Asking because it looks like you measured on the exhaust side and I guess if the intake side is good, it may be that your exhaust temperatures are too high. Which would suggest any future head would suffer the same fate unless you can bring temperatures down with a re-design of the cooling system or something like that. Not sure how, but if you could rig an electric coolant pump directly from the radiator across the exhaust side of the head maybe it would help. That is if the current system doesn't do it that way already.
What is it like on the intake side? Asking because it looks like you measured on the exhaust side and I guess if the intake side is good, it may be that your exhaust temperatures are too high. Which would suggest any future head would suffer the same fate unless you can bring temperatures down with a re-design of the cooling system or something like that. Not sure how, but if you could rig an electric coolant pump directly from the radiator across the exhaust side of the head maybe it would help. That is if the current system doesn't do it that way already.
Right. Now we're cookin'.
That is very good info, Frans.
I think with a cleverly designed system you can beat the heat (ha!). How is the cooling system circulating the coolant through the head? Is it going out of the pump and into the exhaust side or is it going into the intake side?
Does the pump have one of those auxiliary outlets like say on the 807 engine? Or can you put one in? You know, drill/thread, screw in an outlet?
That is very good info, Frans.
I think with a cleverly designed system you can beat the heat (ha!). How is the cooling system circulating the coolant through the head? Is it going out of the pump and into the exhaust side or is it going into the intake side?
Does the pump have one of those auxiliary outlets like say on the 807 engine? Or can you put one in? You know, drill/thread, screw in an outlet?
Your machine shop should be able to do a hardness test on it for you Frans 
Just a question more than a suggestion with the slight difference between intake side warpage and exhaust side warpage can these heads be angle milled slightly not necessarily into perfection but into gasket tolerances ?? if to high of compression ratio's are a problem can a copper head gasket the right thickness be water jetted out that well bring compression ratio's back into line ? With the extra machined ring protrusion already on the top of the sleeves a good seal should be easily accomplished .
As I said it is just a thought ??
Manic gt
As I said it is just a thought ??
Manic gt
I think you are right, you could cut a thicker gasket but the trick is to find someone who does that. Down here specialist machine shops like that are few and far between. Buying off the shelf might be an option too because I am sure Frans is not the first with this problem and the world seems to like the R8G.
The problem of cooling however is not going to go away. I would be reluctant to move on to a new head before that was sorted given the certainty this is going to go the same way.
I found the same problem is present in many block/head designs where the pump outlet goes over the exhaust side, but being at one end of the head/block, you can only guarantee the first cylinder is cooled properly. Ideally you want four pumps, each for one cylinder, supplied directly from the bottom of the radiator. Ideally.
Second best would be a manifold with four outlets, each delivering coolant from the pump directly to one cylinder only. That is what I would look into. If the pump can have some machining done to install an extra outlet, one could imagine a pipe with four outlets calibrated depending how far away form the pump they are such that all supply the same volume flow and plumbed into the head externally. Not that hard to accomplish but it depends greatly on the head architecture how this idea could be implemented.
The problem of cooling however is not going to go away. I would be reluctant to move on to a new head before that was sorted given the certainty this is going to go the same way.
I found the same problem is present in many block/head designs where the pump outlet goes over the exhaust side, but being at one end of the head/block, you can only guarantee the first cylinder is cooled properly. Ideally you want four pumps, each for one cylinder, supplied directly from the bottom of the radiator. Ideally.
Second best would be a manifold with four outlets, each delivering coolant from the pump directly to one cylinder only. That is what I would look into. If the pump can have some machining done to install an extra outlet, one could imagine a pipe with four outlets calibrated depending how far away form the pump they are such that all supply the same volume flow and plumbed into the head externally. Not that hard to accomplish but it depends greatly on the head architecture how this idea could be implemented.
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Prossibly because of different temperature at each cylinder the 12G had a different Weber DCOE at the hot end of the motor. Also a mechanic involved with the R16 rally cars told me that the hot end cylinder ran different jetting on the Weber DCOE that was fitted to them. Can only assume due to the different temperatures.
Frans IS the machine shop, at least for many things.Your machine shop should be able to do a hardness test on it for you Frans
I'm looking forward to seeing his new cave.
If Frans was local, I'd be able to do it. We have the tester at work for Liaison jobs/reports.Frans IS the machine shop, at least for many things.